Cerebrospinal Fluid-Venous Fistula

Cerebrospinal Fluid-Venous Fistula

CVFs can arise from various causes, including:

Trauma: Head or spinal injuries can disrupt the normal barriers between the CSF space and venous structures, leading to a fistula.

Iatrogenic: Certain medical procedures, such as lumbar punctures or spinal surgeries, can inadvertently create CSF-venous connections.

Congenital: Some individuals may have anatomical abnormalities or developmental defects that predispose them to CVFs.

Idiopathic: In some cases, the exact cause of the CVF remains unknown.

Patients with CVFs may experience a range of symptoms, which are primarily related to the altered dynamics of CSF circulation and pressure.

Only 1 patients with CVF with cognitive abnormalities was identified. The most common symptom was headache in both reviews. Brain sag was identified in all patients, whereas CSF leak was identified in only 2 patients with SIH with FTD or dementia (4.9%). An epidural blood or fibrin glue patch was used in all patients with CVF and in 33 patients with SIH with FTD or dementia. Fifty-five patients with CVF (79.7%) and 27 patients with SIH with FTD or dementia (65.9%) had surgery.

Conclusions: The 2 cases and literature reviews show the difficulty in diagnosis and treatment of CVF with cognitive decline. Novel imaging techniques should be used in patients with cognitive decline in whom a CSF leak is suspected. Transvenous embolization or surgery should be considered before patching for treatment of CVF-induced brain sag and resulting dementia 2).

To diagnose CVFs, various imaging techniques are used. These may include digital subtraction myelography (DSM), CT myelography (CTM), magnetic resonance imaging (MRI). CSF-venous fistulas (CVFs), first described in 2014, are an important cause of spontaneous intracranial hypotension. CVFs can be challenging to detect on conventional anatomic imaging because, unlike other types of spinal CSF leak, they do not typically result in pooling of fluid in the epidural space, and imaging signs of CVF may be subtle. Specialized myelographic techniques have been developed to help with CVF identification, but these techniques are not yet widely disseminated. This article reviews the current understanding of CVFs, emphasizing correlations between venous anatomy and imaging findings as well as potential mechanisms for pathogenesis, and describes current imaging techniques used for CVF diagnosis and localization. These techniques are broadly classified into fluoroscopy-based methods, including digital subtraction myelography and dynamic myelography, and cross-sectional methods, including decubitus CT myelography and MR myelography with intrathecal injection of gadolinium. Knowledge of these various options, including their relative advantages and disadvantages, is critical in the care of patients with spontaneous intracranial hypotension. Investigation is ongoing, and continued advances in knowledge about CVFs as well as in optimal imaging detection are anticipated 3)

Lateral decubitus digital subtraction myelography (LD-DSM) and CT myelography (LD-CTM) are mainly used for detection, but the most sensitive method is yet unknown.

Patients with spontaneous intracranial hypotension diagnosed with a Cerebrospinal Fluid-Venous Fistula between January 2021 and December 2022 in which the area of CVF(s) was covered by both diagnostic modalities were included. LD-CTM immediately followed LD-DSM without repositioning the spinal needle, and the second half of the contrast agent was injected at the CT scanner. Patients were awake or mildly sedated. Retrospectively, two neuroradiologists evaluated data independently and blinded for the presence of CVF.

Twenty patients underwent a total of 27 combined LD-DSM/LD-CTM examinations (4/20 with follow-up and 3/20 with bilateral examinations). Both raters identified significantly more CVFs with LD-CTM than with LD-DSM (rater 1: 39 vs 9, P<0.001; rater 2: 42 vs 12, P<0.001). Inter-rater agreement was substantial for LD-DSM (κ=0.732) and LD-CTM (κ=0.655). The results remained significant after considering the senior rating for cases of disagreement (39 vs 10; P<0.001), and no CVF detected on LD-DSM was missed on LD-CTM.

In this study, Lateral decubitus CT myelography has a higher diagnostic yield for the detection of CVFs than LD-DSM and should supplement LD-DSM, but further studies are needed. LD-CTM can be easily acquired in awake or mildly sedated patients with the second half of contrast injected just before CT scanning, or it may be considered as a stand-alone investigation 4).

The study provides valuable insights into the diagnostic yield of LD-DSM and LD-CTM for CVF detection in SIH patients. However, it has limitations related to sample size, study design, and the need for further validation. The findings support the potential role of LD-CTM as a more sensitive diagnostic tool, but its clinical implications and safety considerations should be explored in more detail.

Ultrahigh-Resolution Cone-Beam Computed Tomography 5)

Direct intraoperative visualization of CVF using intrathecal fluorescein. CVF can be identified intraoperatively using fluorescein dye, which can be a valuable adjunct for the surgeon confronted with this disease 6).

DSM had a 90% detection rate of visualizing the exact site of the dural breach in patients with extensive postoperative spinal CSF leaks. The coexistence of a CSF-venous fistula in addition to the primary dural tear was present in about one-fifth of patients. The presence of a CSF-venous fistula should be considered if CSF leak symptoms persist in spite of successful repair of a durotomy 7).

The management of CVFs typically involves interventions aimed at closing or repairing the abnormal communication between the CSF space and the venous system. Treatment options may include:

Blood Patches: In some cases, a targeted epidural or intrathecal blood patch is used to seal the fistula and restore normal CSF pressure.

Embolization: Minimally invasive procedures can be performed to occlude the abnormal connection through the use of embolic materials. Transvenous embolization of CSFVF in SIH patients is safe and effective with a 95% treatment response, significant improvement in imaging outcomes, and a very low rate of complications 8)

Transvenous embolization is independently validated as a highly effective and safe treatment for CVF and is feasible using upper-extremity venous access. Dual-microcatheter and balloon/coil pressure cooker techniques may be used to optimize distribution of embolic material and potentially, treatment efficacy 9).

Surgery: Surgical repair may be necessary in complex cases where other methods are not effective.

Cerebrospinal Fluid-Venous Fistula are increasingly identified as a cause of spontaneous intracranial hypotension (SIH).


Schievink WI, Moser FG, Maya MM. CSF-venous fistula in spontaneous intracranial hypotension. Neurology. 2014 Jul 29;83(5):472-3. doi: 10.1212/WNL.0000000000000639. Epub 2014 Jun 20. PMID: 24951475.

Stuebe C, Jones BA, Syal A, Rahme RJ, Turcotte EL, Toussaint LG 3rd, Ross JS, Bendok BR. Cerebrospinal Venous Fistula Presenting with Cognitive Decline: Systematic Literature Review and Report of Two Cases. World Neurosurg. 2023 Aug;176:74-80. doi: 10.1016/j.wneu.2023.03.056. Epub 2023 Mar 17. PMID: 36934870.

Kranz PG, Gray L, Malinzak MD, Houk JL, Kim DK, Amrhein TJ. CSF-Venous Fistulas: Anatomy and Diagnostic Imaging. AJR Am J Roentgenol. 2021 Dec;217(6):1418-1429. doi: 10.2214/AJR.21.26182. Epub 2021 Jun 30. PMID: 34191547.

Lützen N, Demerath T, Würtemberger U, Belachew NF, Barvulsky Aleman E, Wolf K, El Rahal A, Volz F, Fung C, Beck J, Urbach H. Direct comparison of digital subtraction myelography versus CT myelography in lateral decubitus position: evaluation of diagnostic yield for cerebrospinal fluid-venous fistulas. J Neurointerv Surg. 2023 Nov 2:jnis-2023-020789. doi: 10.1136/jnis-2023-020789. Epub ahead of print. PMID: 37918908.

Lützen N, Beck J, Urbach H. Cerebrospinal Fluid Venous Fistula Imaging with Ultrahigh-Resolution Cone-Beam Computed Tomography. JAMA Neurol. 2023 Aug 1;80(8):870-871. doi: 10.1001/jamaneurol.2023.1640. PMID: 37306975.

Häni L, El Rahal A, Fung C, Volz F, Kraus LM, Lützen N, Urbach H, Schnell O, Beck J. Intraoperative Visualization of Flow in Direct Cerebrospinal Fluid-Venous Fistulas Using Intrathecal Fluorescein. Oper Neurosurg (Hagerstown). 2023 May 1;24(5):e336-e341. doi: 10.1227/ons.0000000000000625. Epub 2023 Feb 10. PMID: 37068025.

Schievink WI, Maya MM, Chu RM, Perry TG, Moser FG, Taché RB, Wadhwa VS, Prasad RS. Postoperative Spinal Cerebrospinal Fluid-Venous Fistulas Associated With Dural Tears in Patients With Intracranial Hypotension or Superficial Siderosis-A Digital Subtraction Myelography Study. Neurosurgery. 2023 Aug 1;93(2):473-479. doi: 10.1227/neu.0000000000002444. Epub 2023 Mar 1. PMID: 36856442.

Brinjikji W, Madhavan A, Garza I, Whealy M, Kissoon N, Mark I, Morris PP, Verdoorn J, Benson J, Atkinson JLD, Kobeissi H, Cutsforth-Gregory JK. Clinical and imaging outcomes of 100 patients with cerebrospinal fluid-venous fistulas treated by transvenous embolization. J Neurointerv Surg. 2023 Oct 28:jnis-2023-021012. doi: 10.1136/jnis-2023-021012. Epub ahead of print. PMID: 37898553.

Parizadeh D, Fermo O, Vibhute P, Gupta V, Arturo Larco JL, Grewal SS, Quinones-Hinojosa A, Erben YM, Clendenen S, Rozen TD, Huynh TJ. Transvenous embolization of cerebrospinal fluid-venous fistulas: Independent validation and feasibility of upper-extremity approach and using dual-microcatheter and balloon pressure cooker technique. J Neurointerv Surg. 2023 Jan 23:jnis-2022-019946. doi: 10.1136/jnis-2022-019946. Epub ahead of print. PMID: 36690439.



Multiple-Choice Test

  1. What is the primary purpose of the ProGav Miethke shunt?
    1. [ ] a. To measure intracranial pressure
    2. [ ] b. To drain cerebrospinal fluid
    3. [X] c. To adjust shunt settings
    4. [ ] d. To detect magnetic fields
  1. How can the setting of the ProGav Miethke shunt be adjusted?
    1. [ ] a. By changing the valve’s diameter
    2. [X] b. By using external magnetic adjustment
    3. [ ] c. By applying pressure to the scalp
    4. [ ] d. By adjusting the gravitational unit
  1. What is the role of the brake system in the ProGav Miethke shunt?
    1. [X] a. To hold the rotor in place during MRI scans
    2. [ ] b. To prevent the shunt from draining cerebrospinal fluid
    3. [ ] c. To adjust the shunt’s opening pressure
    4. [ ] d. To measure the patient’s intracranial pressure
  1. What is the main concern regarding the interaction between the iPhone 12 and programmable ventriculoperitoneal (VP) shunts?
    1. [X] a. Re-programming of shunt settings
    2. [ ] b. Magnetic interference with shunt function
    3. [ ] c. Risk of overdrainage
    4. [ ] d. Pressure changes in the shunt
  1. How did the study find the iPhone 12’s interaction with programmable VP shunts, such as the ProGav Miethke?
    1. [ ] a. The iPhone 12 caused re-programming of shunt settings
    2. [X] b. The iPhone 12 had no effect on the shunt settings
    3. [ ] c. The iPhone 12 increased the risk of overdrainage
    4. [ ] d. The iPhone 12 was not tested with VP shunts
  1. What is the significance of the MRI compatibility of medical implants and devices?
    1. [ ] a. It allows for shunt settings to be determined using MRI scans.
    2. [X] b. It enables patients to undergo MRI scans without shunt interference.
    3. [ ] c. It reduces the risk of re-programming shunt settings during MRI.
    4. [ ] d. It makes MRI scans safer for patients with VP shunts.
  1. What did the study conclude regarding the MRI safety of programmable VP shunt valves for 7T MR systems?
    1. [ ] a. Programmable shunt valves are safe for all 7T MR systems.
    2. [X] b. All programmable shunt valves are MR-unsafe for 7T systems.
    3. [ ] c. Novel programming mechanisms can make shunt valves conditional for 7T MR systems.
    4. [ ] d. The safety of programmable shunt valves for 7T MR systems needs further evaluation.
  1. What is the primary purpose of the Birmingham standardized IIH shunt protocol?
    1. [ ] a. To increase the diameter of the shunt valve
    2. [ ] b. To reduce the use of adjustable shunt valves
    3. [X] c. To standardize CSF shunting in IIH patients
    4. [ ] d. To eliminate the need for VPS insertion
  1. What is the primary focus of the study related to the determination of programmable shunt settings using CT scans?
    1. [ ] a. To assess the compatibility of shunt settings with CT scans
    2. [ ] b. To validate the MRI safety of programmable shunt valves
    3. [X] c. To evaluate the feasibility of determining shunt settings using CT scans
    4. [ ] d. To determine the brake mechanism of programmable shunts
  1. What is the key finding of the study on programmable shunt settings and CT scans?
    1. [ ] a. The shunt settings cannot be determined using CT scans.
    2. [X] b. The shunt settings can be determined accurately using CT scans.
    3. [ ] c. The brake mechanism in programmable shunts is ineffective during CT scans.
    4. [ ] d. The MRI compatibility of programmable shunt valves is not affected by CT scans.

Latest PubMed Related Articles

The ProGav Miethke shunt is a adjustable pressure valve composed of an adjustable balloon-spring valve unit and an integrated overdrainage compensating gravitational valve known as the ShuntAssistant®

Diagrams of the Miethke proGAV® shunt adapted from with the permission of authors. A: Adjustable unit in ‘closed’ state. The ball-in-cone valve is closed and drainage is blocked. B: Adjustable unit in ‘open’ state. Differential pressure overcomes the spring force. The ball moves out of the cone and the gap opens, allowing drainage. C: Gravitational unit in vertical position. When patient is upright unit closes, increasing effective opening pressure of the valve. Drainage occurs when the differential pressure exceeds the combined opening pressures of both unit. D: Gravitational unit in horizontal position. The unit is open and the opening pressure of the valve is determined only by the adjustable unit. E: Internal adjustment mechanism of the shunt with details of profiled rotor controlling pre-load of the spring supporting ball F: The magnetic tool is used to turn the rotor. In neutral position rotor cannot move even in a presence of very strong magnetic field (up to 3T) as the brake is engaged. G: The turning is only possible when the central part of valve’s casing is depressed, releasing the brake.

Mentions: The adjustable unit uses a ball-in-cone valve system. The tension of the spring holding the ball in place can be adjusted by turning the rotor (torsion bar) using the external magnetic adjustment tool, thus changing the operating pressure. The valve has a brake system that holds the rotor in place to prevent unwanted re-adjustment when the shunt is exposed to an external magnetic field. To release the brake, a downward force (800 to 1600 gram-force) is applied to the unit using the adjustment tool (Figure 1). The valve has a diameter of 18 mm. It has a relatively large internal volume compared to other models, which is intended to minimize the risk of obstruction 1).

ProGAV combines the advantages of an adjustable valve with unsurpassed overdrainage protection of the ShuntAssistant® valve antisiphon device.

With this combination, physiological drainage can be maintained in any body position-from supine to upright.

The in-line combination of adjustable differential pressure valves with fixed gravitational units is increasingly recommended in the literature. The spatial positioning of the gravitational unit is thereby decisive for the valve opening pressure. Proven, integrated gravitational unit provides increased resistance as the patient moves to an upright position. 0-20 cm H2O pressure range in 1 cm increments.

Enables the surgeon to provide different opening pressures for the supine and standing positions, managing overdrainage complications and patient discomfort.

Titanium housing allows the proGAV valve to be made very small, but still have large flow paths to help reduce the risk of obstruction.

Portable, hand-held instruments for quick and easy adjustments of pressure. – See more at: http://www.aesculapusa.com/products/neurosurgery/hydrocephalus-shunts/progav#sthash.oGByTPFH.dpuf

The iPhone 12 model has elicited concerns over its interaction with medical devices such as pacemakers due to its integrated MagSafe technology. Historically, programmable ventriculoperitoneal (VP) shunts have been demonstrated to readjust when exposed to magnetic objects. Yet, the presence of interactions between the iPhone 12 and shunts is unknown. In this in-vitro study, we examined the effect on the programming of three VP shunts, Medtronic Strata II, Miethke ProGAV 2.0, and Codman Hakim, when exposed to the iPhone 12 model. We found that all three valves did not re-program when the iPhone was held near or moved in a swiping or rotational motion above the valves. Therefore, the risk of re-programming of these three shunts when exposed to iPhone 12 appears to be low. However, patients should take care until further work is undertaken to examine the complex interplay between programmable VP shunts with magnetic devices 2).

Given the potential implications for patient safety, further research in real-world clinical settings with larger sample sizes and long-term follow-up is warranted. The study raises awareness of the need to understand the complex interplay between programmable VP shunts and magnetic devices and highlights the importance of continued vigilance regarding medical device interactions with evolving technology. Until further research is conducted, patients and healthcare providers should remain cautious and vigilant when using magnetic devices around programmable VP shunts.

Three proGAV 2.0 and 3 CODMAN CERTAS® Plus programmable VP-shunt valves were tested in three steps. 1) Deflection angle tests close to the bore opening at the location of a static magnetic field gradient of 3-5 T/m. 2) Valves were fixed on a spherical phantom in 3 positions (a. lateral, b. cranial, c. cranial with 22.5° tilt anteriorly) and assessed for keeping the programmed pressure setting and re-programmability. 3) Valves were fixed on the phantom and positioned laterally in a radiofrequency head coil. MRI scans were performed for both models, including MPRAGE, GRE, and SE sequences.

Results: Deflection angles were moderate (13°, 14°, 13°) for the proGAV valves and close to critical (43°, 43°, 41°) for the CODMAN valves at the test location. Taking a scaling factor of 2-3 for the maximum spatial magnetic field gradient accessible to a patient within the magnet bore into account renders both valves MR unsafe regarding ferromagnetic attraction. The proGAV valves kept the pressure settings in all positions and were reprogrammable in positions a. and b. In position c., reprogrammability was lost. The CODMAN valves changed their pressure setting and reprogrammability was lost in all positions. MR image signal homogeneity was unaltered in the phantom center, artifacts limit the assessability of structures in close vicinity to the valves.

Both tested programmable VP-shunt valves are MR unsafe for 7T systems. Novel programming mechanisms using permanent magnets with sufficient magnetic coercivity or magnet-free mechanisms may allow the development of programmable VP-shunt valves that are conditional for 7T MR systems 3).

In adjustable or programmable valves, the settings may be changed by external magnetic fields of intensity above 40 mT (exceptions: ProGAVPolaris, and Certas).

The MR-compatibility of medical implants and devices becomes more and more important with the increasing number of high-field MR-scanners employed. Until the end of 2004, about twenty 3T MR in Germany will be in clinical practice. Patients with hydrocephalus need frequent follow-up MR-examinations to assure correct functioning of a shunt.

There is strong evidence for maintenance of function of the valve after exposure to 3T. This also implies the programmable valve, as long as the brake mechanism is properly adjusted during MR-examination.

Unique “Active-Lock” MR Brake prevents inadvertent pressure changes by environmental or MR magnetic fields of 3 Tesla or less 4) 5) 6) 7).

The iPad 3 can not change the pressure settings at a distance comparable to the thickness of certain regions of the scalp. Although the specific rotational motion described may be uncommon in real life, it is nevertheless recommended that children with hydrocephalus, caregivers, educators, and therapists are informed of the now-apparent risks of close contact with this increasingly popular technology 8).

The components of the Birmingham standardized IIH shunt protocol are evidence-based and address the technical challenges of CSF diversion in patients with IIH. This protocol is associated with a low revision rate, and the authors recommend standardization for CSF shunting in IIH.

The protocol comprises the following: shunt surgery by neurosurgeons with expertise in CSF disorders; a frontal VPS usually right-sided but left-sided if the left ventricle is bigger; use of the proGAV 2.0 valve with gravitational unit, set at 10 and the M.scio telemetric sensor; cannulation of the ventricle with StealthStation EM navigation system; and laparoscopic insertion of the peritoneal catheter. The authors describe the protocol rationale and evidence behind each component and present the results of a prospective analysis of revision rates.

The protocol has been implemented since 1 July 2019, and by 28 February 2022, sixty-two patients with IIH had undergone primary VPS insertion. The 30-day revision rate was 6.5%, and overall 11.3% of patients underwent revision during the study period, which compares favorably with the literature. The etiology for early failures was related to the surgical technique 9).

Programmable shunts can be adjusted to optimize CSF diversion in patients with hydrocephalus without the need for re-operation. Currently, all shunts incorporate radiopaque markers so that their setting can be determined on skull X-ray images. The purpose of this study was to evaluate whether the shunt setting could also be determined ex vivo and in vivo using the data from a standard head CT scan since one is nearly always obtained when patients with VP shunts present with new symptoms that could be due to shunt malfunction. Materials and Methods: Four commonly used programmable shunts were attached to a dried skull and scanned using a variety of CT techniques. The shunts imaged were the CertasTM Plus (Codman, Raynham, Massachusetts), Polaris® (Sophysa, Orsay, France), proGAV 2.0® (Braun, Bethlehem, Pennsylvania), and Hakim® (Codman, Raynham, Massachusetts). Each shunt was scanned at two different valve settings using multiple CT techniques: CTDIvol 75, 140kVp, 330mAs, CTDIvol60, 120kVp 390mAs, CTDIvol40, 80kVp with 430mAs, 140kVp with 215mAs. Image reconstruction with and without CT metal suppression software was used for all scans, and the data was reconstructed into volume-rendered images. We enlisted ten observers to review the volume-rendered images only. After a short set of training slides viewed by all observers, they were asked to predict the shunt setting for each valve along with their level of confidence. One clinical case of a patient with a programmable valve was evaluated on a CT scan.

Results: Using the volume-rendered images only, the two shunt settings of the Polaris shunt were correctly predicted by all the observers and in nine of 10 settings for the CertasTM Plus valve. For the Hakim® shunt and the proGAV 2.0® shunt, setting prediction accuracy was 0% and 10%, respectively. In one clinical case, the programmable valve setting could be determined from the CT scan data.

Conclusion: The valve setting of at least two currently available programmable shunts can be determined using volume-rendered images generated from CT data. Reconstructions using metal suppression software were rated as superior and may be necessary for some valve designs 10).

The study’s findings suggest that the setting of certain programmable shunts can be determined using volume-rendered images generated from CT data. This non-invasive approach has the potential to reduce the need for invasive procedures and additional radiation exposure, which is beneficial for patients with hydrocephalus. However, the study’s limitations, including the small observer group and variability in accuracy among different shunt models, indicate that further research is needed to validate the method’s effectiveness. Additionally, a broader clinical evaluation involving more patient cases would enhance the practical application of this technique. The consideration of metal suppression software highlights the importance of optimizing image reconstruction for different valve designs. In conclusion, the study offers a promising avenue for non-invasive shunt setting assessment, but more research is needed to confirm its reliability and clinical utility.


Kumar A, Pervaiz A, Borg A, Abdul-Hamid A, Jeyaretna S, MacKeith S, Qureishi A. Effect of exposure from iPhone 12 on programmable ventriculoperitoneal shunts. Br J Neurosurg. 2022 Jun;36(3):415-419. doi: 10.1080/02688697.2022.2028724. Epub 2022 Jan 21. PMID: 35062838.

Chen B, Dammann P, Jabbarli R, Sure U, Quick HH, Kraff O, Wrede KH. Safety and function of programmable ventriculo-peritoneal shunt valves: An in vitro 7 Tesla magnetic resonance imaging study. PLoS One. 2023 Oct 11;18(10):e0292666. doi: 10.1371/journal.pone.0292666. PMID: 37819939; PMCID: PMC10566673.

Lindner D, Preul C, Trantakis C, Moeller H, Meixensberger J. Effect of 3T MRI on the function of shunt valves–evaluation of Paedi GAV, Dual Switch and proGAV. Eur J Radiol. 2005 Oct;56(1):56-9. PubMed PMID: 16168265.

Allin DM, Czosnyka ZH, Czosnyka M, Richards HK, Pickard JD. In vitro hydrodynamic properties of the Miethke ProGAV hydrocephalus shunt. Cerebrospinal Fluid Res. 2006 Jun 29;3:9. PubMed PMID: 16808836; PubMed Central PMCID: PMC1552084.

Allin DM, Czosnyka M, Richards HK, Pickard JD, Czosnyka ZH. Investigation of the hydrodynamic properties of a new MRI-resistant programmable hydrocephalus shunt. Cerebrospinal Fluid Res. 2008 Apr 21;5:8. doi: 10.1186/1743-8454-5-8. PubMed PMID: 18426562; PubMed Central PMCID: PMC2365935.

Lavinio A, Harding S, Van Der Boogaard F, Czosnyka M, Smielewski P, Richards HK, Pickard JD, Czosnyka ZH. Magnetic field interactions in adjustable hydrocephalus shunts. J Neurosurg Pediatr. 2008 Sep;2(3):222-8. doi: 10.3171/PED/2008/2/9/222. PubMed PMID: 18759607.

He Y, Murphy RK, Roland JL, Limbrick DD Jr. Interactions between programmable shunt valves and the iPad 3 with Smart Cover. Childs Nerv Syst. 2013 Apr;29(4):531-3. doi: 10.1007/s00381-013-2053-4. Epub 2013 Feb 20. PubMed PMID: 23423659.

Tsermoulas G, Thant KZ, Byrne ME, Whiting JL, White AM, Sinclair AJ, Mollan SP. The Birmingham Standardized Idiopathic Intracranial Hypertension Shunt Protocol: Technical Note. World Neurosurg. 2022 Nov;167:147-151. doi: 10.1016/j.wneu.2022.08.154. Epub 2022 Sep 9. PMID: 36089279.

Slonimsky E, Zacharia B, Mamourian A. Determination of Programmable Shunt Setting Using CT: Feasibility Study. Cureus. 2021 Nov 22;13(11):e19818. doi: 10.7759/cureus.19818. PMID: 34963836; PMCID: PMC8702386.

Hürthle cell carcinoma

Hürthle cell carcinoma

Hameed et al. from the Departments of Neurosurgery and Hillman Cancer Center, University of Pittsburgh Pennsylvania. present the case of a patient with HCC metastasis to the skull base, cortex, and spine with recent tibial metastasis.

Despite the presence of metastasis to the cortex, skull base, and spine, the patient responded very well to radiation therapy, sellar mass resection, and cervical spine decompression and fixation and has made a remarkable recovery.

The authors’ multidisciplinary approach to the patient’s care, including a diverse team of specialists from oncology, neurosurgery, orthopedic surgery, radiology, endocrinology, and collaboration with clinical trial researchers, was fundamental to her successful outcome, demonstrating the utility of intersecting specialties in successful outcomes in neuro-oncological patient care 1)

An 81-year-old man who had undergone total thyroidectomy for goiter in the past and presented with metastatic papillary thyroid carcinoma (PTC) to the neck after a gap of 16 years. After two years, the patient developed a solitary cystic brain PTC metastasis associated with raised thyroglobulin (Tg) inside the cystic lesion aspirated during brain surgery. He was admitted for a space-occupying brain lesion in the right frontal lobe. The patient’s history included metastatic disease of PTC to the neck with cervical lymph node metastasis and local recurrence after surgery and radioactive iodine-131 treatment. The patient underwent craniotomy and removal of the lesion. The aspirated fluid was sent for cytological examination and measurement of Tg levels, which were interestingly high. Pathology of the brain lesion revealed infiltration of brain parenchyma from a metastatic lesion characterized by eosinophilic cells with irregular contours forming grooves, resulting in cytoplasmic pseudo-inclusions, an oncotic variant of PTC. This report has shown that residual tissue may be present following total thyroidectomy and may be the origin of PTC with metastasis to the brain. The patient in this study suffered from a brain lesion that could be excised. However, aspiration of cystic compartments could provide a rapid diagnosis in patients with non-removable brain lesions 2).

The first reported patient with an isolated Hurthle cell papillary thyroid carcinoma metastasis to the choroid plexus of the lateral ventricle. Unresponsive to iodine ablation and refusing surgery, the patient underwent Gamma Knife radiosurgery (Elekta AB, Stockholm, Sweden), receiving 15Gy to the 50% isodose line. The lesion regressed until 5 years later at which time it was unresponsive to 18Gy and required surgical resection. Although extraneural metastatic cancers are recognized as potential sources for the single choroid plexus mass, we must consider even the unusual culprit in patients with a history of cancer 3).

McWilliams RR, Giannini C, Hay ID, Atkinson JL, Stafford SL, Buckner JC. Management of brain metastases from thyroid carcinoma: a study of 16 pathologically confirmed cases over 25 years. Cancer. 2003 Jul 15;98(2):356-62. doi: 10.1002/cncr.11488. PMID: 12872357.


Hameed NUF, Hoppe MM, Habib A, Head J, Shanahan R, Gross BA, Narayanan S, Zenonos G, Zinn P. Surgical management of metastatic Hürthle cell carcinoma to the skull base, cortex, and spine: illustrative case. J Neurosurg Case Lessons. 2023 Oct 9;6(15):CASE23263. doi: 10.3171/CASE23263. PMID: 37910014.

Ntotsikas K, Lazarioti S, Daraki V, Drakos E, Tsakalomatis PN, Syntzanaki EK, Moustakis N, Marinis AI, Salapatas-Gkinis A, Xekouki P, Vakis A, Tsitsipanis C. Thyroglobulin as a Rapid and Cost-Effective Biomarker for Diagnosis of Thyroid Carcinoma Brain Metastasis: A Case Report of a Patient with Metastatic Hurthle Cell Thyroid Carcinoma. Am J Case Rep. 2023 Oct 19;24:e939025. doi: 10.12659/AJCR.939025. PMID: 37853680; PMCID: PMC10598507.

Healy AT, Otvos B, Schroeder J, Hamrahian AH, Angelov L, Kamian K. Hurthle cell carcinoma presenting as a single choroid plexus metastasis. J Clin Neurosci. 2014 Aug;21(8):1448-50. doi: 10.1016/j.jocn.2013.12.012. Epub 2014 Jan 24. PMID: 246567

Moyamoya Disease Pathogenesis

Moyamoya Disease Pathogenesis

There is a strong genetic component to Moyamoya disease. It can run in families, and specific genetic mutations have been associated with the condition. Mutations in certain genes, such as the RNF213 gene, are more prevalent in individuals with Moyamoya disease. These genetic factors can contribute to the development of the abnormal blood vessels characteristic of the disease.

see RNF213 in Moyamoya Disease Pathogenesis.

One of the hallmarks of Moyamoya disease is the development of small, fragile blood vessels (called “moyamoya vessels”) to compensate for the lack of blood flow through the narrowed or blocked arteries. These new blood vessels are often disorganized and prone to bleeding, which can lead to the symptoms and complications of Moyamoya disease.

Angiogenic factors associated with Moyamoya disease (MMD) are overexpressed in M2 polarized microglia in ischemic stroke, suggesting that microglia may be involved in the pathophysiology of MMD; however, existing approaches are not applicable to explore this hypothesis. Herein we applied blood-induced microglial-like (iMG) cells. We recruited 25 adult patients with MMD and 24 healthy volunteers. Patients with MMD were subdivided into progressive (N = 7) or stable (N = 18) groups whether novel symptoms or radiographic advancement of the Suzuki stage within 1 year was observed or not. We produced 3 types of iMG cells; resting, M1-, and M2-induced cells from monocytes, then RNA sequencing followed by GO and KEGG pathway enrichment analysis and qPCR assay was performed. RNA sequencing of M2-induced iMG cells revealed that 600 genes were significantly upregulated (338) or downregulated (262) in patients with MMD. Inflammation immune-related factors and angiogenesis-related factors were specifically associated with MMD in GO analysis. qPCR for MMP9, VEGFA, and TGFB1 expression validated these findings. This study is the first to demonstrate that M2 microglia may be involved in the angiogenic process of MMD. The iMG technique provides a promising approach to exploring the bioactivity of microglia in cerebrovascular diseases 1)

While genetic factors play a significant role, environmental factors may also contribute to the development of Moyamoya disease. Some studies suggest that certain environmental factors, such as viral infections or radiation exposure, may trigger or exacerbate the condition in genetically susceptible individuals.

Some researchers believe that an autoimmune or inflammatory component may be involved in the pathogenesis of Moyamoya disease. Autoimmune reactions or chronic inflammation could contribute to the narrowing of blood vessels and the formation of moyamoya vessels.

Abhinavet al. investigated 62 secreted factors in both MMD subtypes (ischemic and hemorrhagic) and examined their relationship with preoperative perfusion status, the extent of postoperative angiographic revascularization, and functional outcomes. Intraoperative CSF was collected from 32 control and 71 MMD patients (37 ischemic and 34 hemorrhagic). Multiplex Luminex assay analysis showed that 41 molecules were significantly elevated in both MMD subtypes when compared to controls, including platelet-derived growth factor-BB (PDGF-BB), plasminogen activator inhibitor 1 (PAI-1), and intercellular adhesion molecule 1 (ICAM1) (p < 0.001). Many of these secreted proteins have not been previously reported in MMD, including interleukins (IL-2, IL-4, IL-5, IL-7, IL-8, IL-9, IL-17, IL-18, IL-22, and IL-23) and C-X-C motif chemokines (CXCL1 and CXCL9). Pathway analysis indicated that both MMD subtypes exhibited similar cellular/molecular functions and pathways, including cellular activation, migration, and inflammatory response. While neuroinflammation and dendritic cell pathways were activated in MMD patients, lipid signaling pathways involving nuclear receptors, peroxisome proliferator-activated receptor (PPAR), and liver X receptors (LXR)/retinoid X receptors (RXR) signaling were inhibited. IL-13 and IL-2 were negatively correlated with preoperative cerebral perfusion status, while 7 factors were positively correlated with the extent of postoperative revascularization. These elevated cytokines, chemokines, and growth factors in CSF may contribute to the pathogenesis of MMD and represent potential future therapeutic targets 2).

An HLA imputation was conducted to explore the relationship between HLA and patients with moyamoya disease (MMD) in the Chinese Han population.

In this study, Wan et al. performed an association analysis of the major histocompatibility complex region in 2,786 individuals of Chinese Han ancestry (2,031 controls and 755 patients with MMD), through a widely used HLA imputation method.

They identified that the variant rs3129731 (odds ratio [OR] = 1.79, p = 3.69 × 10-16) located between the MTCO3P1 and HLA-DQA2 is a major genetic risk factor for MMD. In addition to this variant, found in the conditional association analysis, we also detected another independent signal, rs1071817 (OR = 0.62, p = 1.20 × 10-11), in HLA-B.

This research suggests that the genetic polymorphism of HLA-DQA2 and HLA-B could be a genetic predisposing factor for MMD in Chinese Han. This may provide some evidence for further HLA-related studies of patients with MMD of Chinese Han ethnicity and indicates that MMD is an autoimmune disease 3).

Endothelial cells lining the blood vessels play a crucial role in regulating blood flow and vessel health. Dysfunction of these cells can contribute to the narrowing of arteries and the development of Moyamoya disease.

In cases of endothelial dysfunction, the endothelium may produce less nitric oxide, a molecule that helps relax blood vessels and regulate blood flow. Reduced nitric oxide production can lead to vasoconstriction, or the narrowing of blood vessels, contributing to reduced blood flow in the affected arteries.

FLNA (filamin A) and ZYX (zyxin) proteins were significantly higher in Moyamoya Disease serum compared with those in health controls (Log2FC >2.9 and >2.8, respectively). Immunofluorescence revealed an intimal hyperplasia in the superficial temporal artery and middle cerebral artery specimens of MMD. FLNA and ZYX proteins increased the proportion of endothelial cells in the S phase and promoted their proliferationangiogenesis, and cytoskeleton enlargement. Mechanistic studies revealed that AKT (serine/threonine kinase)/GSK-3β (glycogen synthase kinase 3β)/β-catenin signaling pathway plays a major role in these FLNA- and ZYX-induced changes in endothelial cells.

This study provides proteomic data on a large sample size of Moyamoya Disease. The differential expression of FLNA and ZYX in patients with MMD and following in vitro experiments suggest that these upregulated proteins are related to the pathology of cerebrovascular intimal hyperplasia in MMD and are involved in Moyamoya Disease pathogenesis, with diagnostic and therapeutic ramifications 4).

Abnormal blood flow patterns in the brain, such as increased turbulence or changes in blood pressure, may contribute to the development of Moyamoya disease. Hemodynamic stress can lead to vascular remodeling and the formation of moyamoya vessels.

The precise interplay of these factors and the underlying mechanisms leading to Moyamoya disease are still the subject of ongoing research. While genetic factors are clearly involved, the condition is likely to result from a complex interplay of genetic and environmental factors. Treatment for Moyamoya disease often involves surgical procedures to improve blood flow to the brain, such as indirect bypass surgeries or direct revascularization procedures. Early diagnosis and intervention are crucial to prevent severe complications like strokes.


Shirozu N, Ohgidani M, Hata N, Tanaka S, Inamine S, Sagata N, Kimura T, Inoue I, Arimura K, Nakamizo A, Nishimura A, Maehara N, Takagishi S, Iwaki K, Nakao T, Masuda K, Sakai Y, Mizoguchi M, Yoshimoto K, Kato TA. Angiogenic and inflammatory responses in human induced microglia-like (iMG) cells from patients with Moyamoya disease. Sci Rep. 2023 Sep 8;13(1):14842. doi: 10.1038/s41598-023-41456-z. PMID: 37684266; PMCID: PMC10491754.

Abhinav K, Lee AG, Pendharkar AV, Bigder M, Bet A, Rosenberg-Hasson Y, Cheng MY, Steinberg GK. Comprehensive Profiling of Secreted Factors in the Cerebrospinal Fluid of Moyamoya Disease Patients. Transl Stroke Res. 2023 Feb 6. doi: 10.1007/s12975-023-01135-7. Epub ahead of print. PMID: 36745304.

Wan J, Ling W, Zhengshan Z, Xianbo Z, Lian D, Kai W. Association of HLA-DQA2 and HLA-B With Moyamoya Disease in the Chinese Han Population. Neurol Genet. 2021 Jun 2;7(3):e592. doi: 10.1212/NXG.0000000000000592. PMID: 34095496; PMCID: PMC8176556.

He S, Zhang J, Liu Z, Wang Y, Hao X, Wang X, Zhou Z, Ye X, Zhao Y, Zhao Y, Wang R. Upregulated Cytoskeletal Proteins Promote Pathological Angiogenesis in Moyamoya Disease. Stroke. 2023 Oct 27. doi: 10.1161/STROKEAHA.123.044476. Epub ahead of print. PMID: 37886851.

Opioids for chronic pain treatment

Opioids for chronic pain treatment

Efficacy: Opioids can be highly effective for managing certain types of chronic pain, especially when other treatments have failed. They are typically reserved for severe pain, such as cancer-related pain or pain following major surgery.

Risks and Side Effects: Opioids come with significant risks and side effects. These can include physical dependence, tolerance (requiring higher doses for the same effect), withdrawal symptoms, constipation, drowsiness, and the potential for overdose, which can be fatal.

Alternative Treatments: Many alternative treatments are available for chronic pain, depending on the underlying cause. These may include physical therapy, non-opioid medications, lifestyle modifications, cognitive-behavioral therapy, and interventional procedures like nerve blocks.

Opioid Prescribing Guidelines: To address the opioid epidemic, many countries, including the United States, have established stricter guidelines for opioid prescribing. These guidelines aim to limit the use of opioids for chronic pain and promote safer prescribing practices.

Patient Education: Patients and healthcare providers should engage in open and honest discussions about the benefits and risks of using opioids for chronic pain management. It’s essential for patients to be informed about the potential side effects and risks, as well as to have a clear understanding of the treatment plan and goals.

Monitoring and Follow-Up: Opioid therapy for chronic pain should be closely monitored by a healthcare provider. Regular check-ups are important to assess the effectiveness of the treatment, monitor for any signs of misuse or dependence, and adjust the treatment plan as necessary.

Risk Assessment: Healthcare providers should conduct a thorough assessment of each patient’s risk factors for opioid misuse, addiction, and overdose before prescribing opioids for chronic pain. This may involve screening tools and discussions about the patient’s medical history and substance use history.

Multi-Disciplinary Approach: Chronic pain management often benefits from a multidisciplinary approach, which can include a combination of therapies, treatments, and support from different healthcare professionals, such as pain specialists, physical therapists, and mental health professionals.

It’s important to note that the use of opioids for chronic pain is a complex issue that should be approached with caution and care. In recent years, there has been a growing emphasis on reducing opioid prescriptions and promoting alternative treatments due to the opioid epidemic and the associated risks. Patients with chronic pain should work closely with their healthcare providers to develop a personalized pain management plan that considers their specific needs, circumstances, and the potential benefits and risks of opioid therapy.

The risk of addiction associated with the use of opioids for chronic pain treatment is a significant concern and a topic of extensive research and clinical consideration. It’s crucial to understand that while opioids can be effective at managing pain, they also carry a substantial risk of addiction, especially when used for an extended period. Here are some key points to consider regarding the risk of addiction associated with opioids for chronic pain treatment:

Dependence vs. Addiction: It’s important to differentiate between physical dependence and addiction. Physical dependence occurs when the body becomes accustomed to the presence of the opioid, leading to withdrawal symptoms when the medication is discontinued. Addiction, on the other hand, involves compulsive drug use, cravings, and a loss of control over drug-seeking behavior.

Risk Factors: Several risk factors can increase the likelihood of developing an opioid addiction, including a personal or family history of substance use disorders, a history of mental health issues, and a history of previous substance misuse.

Duration of Use: The longer opioids are used, the greater the risk of developing addiction. While they may be appropriate for short-term pain management, using them for an extended period increases the likelihood of dependence and addiction.

Dosing and Tolerance: Opioid tolerance can develop over time, leading individuals to require higher doses to achieve the same level of pain relief. This can contribute to the risk of addiction, as increasing doses can heighten the potential for dependence.

Prescribing Practices: Prescribing practices play a crucial role in the risk of opioid addiction. Healthcare providers should carefully assess patients for their suitability for opioid therapy, prescribe the lowest effective dose, and monitor patients for signs of misuse or addiction.

Alternative Treatments: For chronic pain management, there are often alternative treatments available that carry a lower risk of addiction, such as non-opioid medications, physical therapy, acupuncture, and behavioral interventions. These options should be considered before resorting to opioids.

Opioid Epidemic: The opioid epidemic in many countries, including the United States, has raised awareness of the risks associated with opioid use. Stricter guidelines and regulations have been put in place to reduce opioid prescribing, especially for chronic pain.

Education and Monitoring: Patients and healthcare providers should engage in open and honest communication about the risks associated with opioids. Regular monitoring and evaluation of the patient’s condition and pain management plan are essential to identify any early signs of misuse or addiction.

Treatment for Addiction: If addiction does develop, it’s crucial to provide access to appropriate treatment and support. Medications like buprenorphine and methadone, along with counseling and behavioral therapies, can be effective in managing opioid addiction.

In summary, while opioids can be effective in managing chronic pain, their potential for addiction is a substantial concern. The risk of addiction is influenced by various factors, including the duration of use, dosing, personal history, and prescribing practices. It’s essential for both patients and healthcare providers to be informed about these risks and to carefully weigh the benefits and potential harms of using opioids for chronic pain treatment. In many cases, alternative, less addictive treatments may be more suitable for managing chronic pain.

A qualitative descriptive study used a content analysis of semistructured interviews. Themes were identified through a reflective, iterative coding process. Consolidated criteria for reporting qualitative research guidelines were followed.

Setting: West Virginia.

Participants: Twenty people who used opioids to treat a CP condition, 10 pharmacists, 10 primary care providers, and 10 specialists.

Intervention: Semistructured interviews.

Main outcome measure: To better understand the impact of restrictive prescribing measures on people who used opioids for CP.

Results: Patients initiated opioids for acute, painful conditions and described how long-term use led to physical dependence and, for some, opioid use disorder. Restrictive opioid prescribing laws led to care interruptions and decreased access and availability of prescribed opioid pain medication, driving some patients to seek illicit drugs. Economic considerations influenced drug use as the price of purchasing prescription opioids on the street went up, making heroin a cheaper alternative. Patients who transitioned to buprenorphine/naloxone as a treatment for pain or opioid use disorder viewed it as a positive change and a “life saver.”

Conclusions: Opioid use for CP is complex and multifaceted. The continuum of pain and opioid use disorder can begin with a prescription for acute pain and continue for the treatment of CP. Patients described how continued opioid use was not to “get high” but for pain control to improve their quality of life, continue to work, and be productive. For those who experience physical dependence on opioids, access to treatment is vital to recovery and pain management.

Key message: Without individualized managed care, people confronted with a sudden interruption in prescription opioids may turn to illicit drugs to mitigate symptoms of opioid withdrawal and physical dependence 1).

In conclusion, the study offers valuable insights into the challenges faced by individuals using opioids for chronic pain and the unintended consequences of restrictive prescribing measures. It emphasizes the importance of tailored, comprehensive care and access to appropriate treatments, taking into account the complex interplay of chronic pain, opioid use, and opioid use disorder. The findings have relevance not only in West Virginia but also in regions grappling with similar issues related to opioids and chronic pain management.

There is no evidence to support the use of epidural injections of steroids, local anesthetics and/or opioids for low back pain without radiculopathy

Opioid may be required for severe pain, usually severe radicular pain. For non-specific back pain, there was no earlier return to full activity than with Nonsteroidal anti-inflammatory drug or APAP 2) Opioids should not be used > 2–3 weeks, at which time NSAIDs should be instituted unless contraindicated

see Opioid for low back pain.

Opioids remain a mainstay in the treatment of acute and chronic pain, despite numerous and potentially dangerous side effects. There is a great unmet medical need for alternative treatments for patients suffering from pain that do not result in addiction or adverse side effects.

Since 2016, 35 of 50 USA states have passed opioid-limiting laws.

Implementation of mandatory opioid prescribing limits effectively decreased 30-day postoperative opioid utilization following ACDF without a rebound increase in prescription refills, ED visits, unplanned hospital readmissions, or reoperations for pain 3).

Intrathecal (IT) opioid pumps are one therapeutic cornerstone of refractory non-malignant pain syndromes. The aim of this study was to evaluate efficacy, surgical and pharmacological complications of IT pumps beyond a time span of 10 years.

In this retrospective single-center cohort study, 27 patients (14 female, 13 male, age 64.0 ± 8.9 (median, 1 SD) yrs) were identified. Pain intensity using the numerical rating scale (NRS), pain and IT pump characteristics, and complications were analyzed. The German Pain Questionaire was used to investigate the physical and mental health status.

Overall time of IT therapy from first implantation to last follow-up was 20.4 ± 6.0 yrs. Time to implantation of the second pump (n=18) was 10.0 ± 5.3 yrs, between the second and third pump (n=6) 6.5 ± 2.7 yrs, and two patients received their 4th pump six years later. Before implantation, NRS was 9.0 ± 0.9, one year after implantation 7.0 ± 1.8 and 4.0 ± 2.3 at the last follow-up. IT drug dose remained stable after 3 years. Opioid intoxications occurred in three patients (10%). One patient (3%) underwent revision surgery due to a catheter infection. Drug side effects occurred in 4 patients (14%). Our patient group has pain-related restrictions in physical activities with menial impact regarding mental and emotional stress.

Even after a time span of over 15 years and several exchanges of pump systems, pain intensity is still reduced. After 3 years, IT drug dose remained unchanged with low side-effects and complication rates 4).


Sedney CL, Dekeseredy P, Davis M, Haggerty T. A qualitative study of chronic pain and opioid use: The impact of restrictive prescribing. J Opioid Manag. 2023 Special-Issue;19(7):95-102. doi: 10.5055/jom.2023.0803. PMID: 37879664.

Bigos S, Bowyer O, Braen G, et al. Acute Low Back Problems in Adults. Clinical Practice Guideline No.14. AHCPR Publication No. 95-0642. Rockville, MD: Agency for Health Care Policy and Research, Public Health Service, U.S. Department of Health and Human Services; 1994

Reid DBC, Patel SA, Shah KN, Shapiro BH, Ruddell JH, Akelman E, Palumbo MA, Daniels AH. Opioid-Limiting Legislation Associated with Decreased 30-Day Opioid Utilization Following Anterior Cervical Decompression and Fusion. Spine J. 2019 Sep 2. pii: S1529-9430(19)30960-X. doi: 10.1016/j.spinee.2019.08.014. [Epub ahead of print] PubMed PMID: 31487559.

Sommer B, Karageorgos N, AlSharif M, Stubbe H, Hans FJ. Long-term outcome and adverse events of intrathecal opiod therapy for non-malignant pain syndrome. Pain Pract. 2019 Jul 10. doi: 10.1111/papr.12818. [Epub ahead of print] PubMed PMID: 31291509.

Intraoperative Angiography

Enhancing Surgical Precision with Intraoperative Angiography: Real-time Visualization in Vascular and Neurosurgical Procedures

Multiple Choice Test: Intraoperative Angiography

  1. [ ] What is the primary purpose of intraoperative angiography?
    1. [ ] To monitor the patient’s vital signs during surgery.
    2. [x] To provide real-time visualization of blood vessels during surgery.
    3. [ ] To administer anesthesia to the patient.
    4. [ ] To remove blood clots from the bloodstream.
  1. [ ] Which imaging equipment is commonly used for intraoperative angiography?
    1. [ ] Magnetic resonance imaging (MRI)
    2. [ ] Ultrasound machine
    3. [x] C-arm fluoroscopy machine
    4. [ ] Electrocardiogram (ECG) machine
  1. [ ] How does intraoperative angiography contribute to surgical outcomes?
    1. [ ] It speeds up the surgery.
    2. [ ] It reduces the need for postoperative physical therapy.
    3. [x] It allows for immediate assessment and intervention, reducing complications.
    4. [ ] It eliminates the need for contrast dye injection.
  1. [ ] Which access site options are mentioned for intraoperative angiography?
    1. [ ] Transverse thoracic access
    2. [x] Transfemoral, transradial, and transulnar access
    3. [ ] Transcatheter aortic access
    4. [ ] Transcranial access
  1. [ ] What is the significance of using transradial and transulnar access sites for neuro-interventional procedures?
    1. [ ] They are more cost-effective.
    2. [ ] They provide better image quality.
    3. [x] They are safer and preferred by patients.
    4. [ ] They are only suitable for cardiac procedures.
  1. [ ] In which patient positions can intraoperative angiography be safely performed?
    1. [ ] Supine position only
    2. [x] Prone, three-quarters prone, and park-bench positions
    3. [ ] Sitting position
    4. [ ] Lateral decubitus position
  1. [ ] What are the indications for using intraoperative angiography?
    1. [ ] Diagnosis of diabetes
    2. [x] Aneurysm surgery and arteriovenous malformation surgery
    3. [ ] Orthopedic surgery
    4. [ ] Cosmetic surgery
  1. [ ] Which contrast agent can be used for intraoperative angiography to visualize surface vessels?
    1. [ ] Iodinated contrast
    2. [ ] Gadolinium
    3. [ ] Barium sulfate
    4. [x] Indocyanine green
  1. [ ] What is the main advantage of intraoperative digital subtraction angiography (ioDSA) in neurovascular procedures?
    1. [ ] It has a lower cost.
    2. [ ] It has a higher availability.
    3. [x] It is highly efficient and has a low risk of complications.
    4. [ ] It is suitable for all patients.
  1. [ ] Why might ioDSA be best suited for selected patients with complex neurovascular pathologies?
    1. [ ] Due to its lower cost and higher availability.
    2. [ ] Because it eliminates the need for other imaging modalities.
    3. [ ] Because it is faster than other angiography techniques.
    4. [x] Because it can potentially detect perfusion rests and remnants, leading to changes in the surgical strategy.

Intraoperative angiography is a valuable medical imaging technique used in vascular and neurosurgical procedures to provide real-time visualization of blood vessels. It involves the injection of contrast dye into the bloodstream and the use of specialized imaging equipment, such as C-arm fluoroscopy machines. Intraoperative angiography allows for immediate assessment of blood vessels, detection of abnormalities, and on-the-spot interventions to ensure optimal blood flow. It offers real-time feedback to surgical teams, reducing postoperative complications and improving surgical outcomes. The choice of access site, whether transfemoral, transradial, or transulnar, is influenced by safety and patient satisfaction considerations. Studies have shown that these alternative access sites are safe and effective for neuro-interventional procedures. Furthermore, the use of intraoperative angiography in various patient positions, such as prone or park-bench, has been found to be feasible and safe, with a notable rate of surgical adjustment/revision. Indications for intraoperative angiography include aneurysm surgery and arteriovenous malformation surgery, with options for contrast agents including traditional iodinated contrast and indocyanine green. The value of intraoperative angiography is particularly evident when used in combination with other imaging modalities, such as indocyanine green videoangiography. A risk-benefit analysis has shown that intraoperative digital subtraction angiography (ioDSA) is efficient, with low complication rates. IoDSA can potentially detect perfusion rests and remnants, leading to changes in the surgical strategy. However, due to its higher costs and lower availability compared to indocyanine green angiography, ioDSA may be best suited for selected patients with complex neurovascular pathologies.*

Overall, intraoperative angiography is a powerful tool that enhances surgical procedures, improves patient outcomes, and contributes to the safety and efficacy of neurovascular surgeries.

Keywords: Intraoperative angiography, medical imaging, real-time visualization, vascular surgery, neurosurgery, contrast dye, imaging equipment, real-time assessment, complications, outcomes, access, transfemoral approach, transradial access, transulnar access, safety, efficacy, prone position, indocyanine green, arteriovenous malformation, aneurysm, arteriovenous fistula, surgical microscope, robotic c-arm, risk-benefit analysis.

Intraoperative angiography is a medical imaging technique that is performed during surgery to visualize blood vessels in real time. It is particularly useful in various surgical procedures, especially those involving vascular surgery and neurosurgery. The goal of intraoperative angiography is to assess the patency, location, and integrity of blood vessels and make necessary adjustments or corrections during the surgical procedure.

Here’s how intraoperative angiography works:

Preparation: Before the surgery, the patient may be prepared by injecting a contrast dye into the bloodstream. This dye helps to make the blood vessels more visible on X-ray or fluoroscopy images.

Imaging Equipment: During the surgery, the surgeon uses specialized imaging equipment such as a C-arm fluoroscopy machine or a mobile angiography unit. The C-arm is a movable X-ray machine that can be positioned over the surgical area to capture real-time images.

Real-Time Imaging: The surgeon or a radiologic technologist can take X-ray images or perform fluoroscopy (continuous X-ray imaging) to visualize the blood vessels. The contrast dye in the bloodstream makes the vessels stand out on the images.

Assessment: Intraoperative angiography allows the surgeon to assess the blood flow, detect any obstructions or abnormalities, and ensure that the surgical procedure is proceeding as planned. For example, in vascular surgery, it can help identify stenoses (narrowing of blood vessels) or blockages.

Intervention: If a problem is identified, such as a blockage or aneurysm, the surgeon can take immediate corrective action, such as placing stents, removing clots, or reshaping blood vessels.

Confirmation: After the necessary adjustments or repairs have been made, another round of angiography is performed to confirm that the blood vessels are functioning properly. This step is crucial for assessing the success of the surgical procedure.

Intraoperative angiography has several advantages:

Real-time assessment: It provides immediate feedback to the surgical team, allowing them to adjust their actions as needed. Minimized complications: Identifying and addressing issues during surgery can reduce the risk of postoperative complications. Improved outcomes: Ensuring optimal blood flow can lead to better surgical outcomes, especially in procedures involving critical organs or vascular structures. However, it’s important to note that the use of X-ray radiation and contrast dye carries some inherent risks, so the benefits of intraoperative angiography must be carefully weighed against potential risks, and the procedure should be performed by skilled professionals with appropriate safety measures in place.

Historically, the transfemoral approach (TFA) has been the most common access site for cerebral intraoperative angiography (IOA). However, in line with trends in cardiac interventional vascular access preferences, the transradial access (TRA) and transulnar access (TUA) have been gaining popularity owing to favorable safety and patient satisfaction outcomes.

Tudor et al. compared the efficacy and safety of TRA/TUA and TFA for cerebral and spinal IOA at an institutional level over a 6-year period.

Methods: Between July 2016 and December 2022, 317 angiograms were included in our analysis, comprising 60 TRA, 10 TUA, 243 TFA, and 4 transpopliteal approach cases. Fluoroscopy time, contrast dose, reference air kerma, and dose-area products per target vessel catheterized were primary endpoints. Multivariate regression analyses were conducted to evaluate predictors of elevated contrast dose and radiation exposure and to assess time trends in access site selection.

Results: Contrast dose and radiation exposure metrics per vessel catheterized were not significantly different between access site groups when controlling for patient position, operative region, 3D rotational angiography use, and different operators. Access site was not a significant independent predictor of elevated radiation exposure or contrast dose. There was a significant relationship between case number and operative indication over the study period (P<0.001), with a decrease in the proportion of cases for aneurysm treatment offset by increases in total cases for the management of arteriovenous malformation, AVF, and moyamoya disease.

TRA and TUA are safe and effective access site options for neuro-interventional procedures that are increasingly used for IOA 1).

Vivanco-Suarez et al reviewed (between January 1960 and July 2022) all studies in which IOAs were performed during neurosurgical procedures with patients in either prone, three-quarters prone, or park-bench positions. Additionally, a cohort of patients from self-institutional experience was included. Efficacy outcomes were the rate of successful angiography and the rate of surgical adjustment/revision after IOA. Safety outcomes were the rate of angiography-related complications and mortality. Data were analyzed using a random-effects meta-analysis of proportions, and statistical heterogeneity was assessed.

A total of 26 studies with 142 patients plus 32 subjects from their own institutions were included in the analysis. The rate of successful intraoperative angiography was 98% (95% CI 94% to 99%; I2=0%). The rate of surgical adjustment/revision was 18% (95% CI 12% to 28%; I2=0%). The rate of complications related to the angiography was 1% (95% CI 0% to 5%; I2=0%). There were no deaths associated with IOA.

They found that IOA performed with patients in prone, three-quarters prone, and park-bench positions is feasible and safe with a non-negligible rate of intraoperative post-angiographical surgical adjustment/revision. The findings suggest that the performance of IOA to complement vascular neurosurgical procedures might have a valuable role in favoring patient outcomes 2).

Typically used in aneurysm surgery to confirm exclusion of the aneurysm from the circulation and to verify patency of critical adjacent vessels, and during AVM surgery to confirm total elimination of the nidus.

1. using traditional iodinated contrast and fluoroscopy. Requires use of Radiolucent Head Frame. Typically the introducer sheath is placed in the femoral artery at the time of initial pre-op angio, and is left in place for intraoperative use.

2. indocyanine green (ICG3) 4) : can be visualized under normal light, or sometimes to better advantage when illuminated with near-infrared light. Use is restricted to surface vessels. May be less reliable with giant or wide necked aneurysms or with thick walled atherosclerotic.

Among the different arterial accesses, the femoral access is the main approach for intraoperative angiography (IOA) performed in a prone position. Without a standardized protocol, however, the application of prone IOAs in intracranial arteriovenous malformation (AVM) or arteriovenous fistula (AVF) surgery remains limited by its procedural complexity 5).

Surgical microscope-integrated intraoperative angiography with intravenous injection of indocyanine green (ICG) has been widely used during bypass or aneurysm surgery. Instead of intravenous injection of ICG.

Intraoperative digital subtraction angiography (ioDSA) allows early treatment evaluation after neurovascular procedures. However, the value and efficiency of this procedure has been discussed controversially. Durner et al. from Günzburg, evaluated the additional value of hybrid operating room equipped with an Artis Zeego robotic c-arm regarding costefficiency and workflow. Furthermore, they performed a risk-benefit analysis and compared it with indocyanine green videoangiography.

For 3 consecutive years, they examined all neurovascular patients, treated in the hybrid operating theater in a risk-benefit analysis. After using microdoppler and ICG angiography for best operative result, every patient received an additional ioDSA to look for remnants or unfavorable clip placement which might lead to a change of operating strategy or results. Furthermore, a workflow-analysis reviewing operating steps, staff positioning, costs, technical errors or complications were conducted on randomly selected cases.

54 patients were enrolled in the risk-benefit analysis, 22 in the workflow analysis. The average duration of a cerebrovascular operation was 4 h 58 min 2 min 35 s accounted for ICG angiography, 46 min 4 s for ioDSA. Adverse events occurred during one ioDSA. In risk-benefit analysis, ioDSA was able to detect a perfusion rest in 2 out of 43 cases (4,7%) of aneurysm surgery, which could not have been visualized by ICG angiography before. In arterio-venous-malformation (AVM) surgery, one of 11 examined patients (7,7%) showed a remnant in ioDSA and resulted in additional resection. The average cost of an ioDSA in Ulm University can be estimated with 1928,00€.

According to the results ioDSA associated complications are low. Relevant findings in ioDSA can potentially avoid additional intervention, however, due to the high costs and lower availability, the main advantage might lie in the treatment of selected patients with complexes neurovascular pathologies since ICG angiography is equally safe but associated with lower costs and better availability 6).


Tudor T, Sussman J, Sioutas GS, Salem MM, Muhammad N, Romeo D, Corral Tarbay A, Kim Y, Ng J, Rhodes IJ, Gajjar A, Hurst RW, Pukenas B, Bagley L, Choudhri OA, Zager EL, Srinivasan VM, Jankowitz BT, Burkhardt JK. Intraoperative angiography in neurosurgery: temporal trend, access site, and operative indication considerations from a 6-year institutional experience. J Neurointerv Surg. 2023 Oct 18:jnis-2023-020709. doi: 10.1136/jnis-2023-020709. Epub ahead of print. PMID: 37852753.

Vivanco-Suarez J, Sioutas GS, Matache IM, Muhammad N, Salem MM, Kandregula S, Jankowitz BT, Burkhardt JK, Srinivasan VM. Intraoperative angiography during neurosurgical procedures on patients in prone, three-quarters prone, and park-bench positions: tertiary single-center experience with systematic review and meta-analysis. J Neurointerv Surg. 2023 Aug;15(8):793-800. doi: 10.1136/jnis-2022-020035. Epub 2023 Apr 17. PMID: 37068942.

Raabe A, Nakaji P, Beck J, Kim LJ, Hsu FP, Kamerman JD, Seifert V, Spetzler RF. Prospective evaluation of surgical microscope-integrated intraoperative near-infrared indocyanine green videoangiography during aneurysm surgery. J Neurosurg. 2005; 103:982–989

Dashti R, Laakso A, Niemela M, Porras M, Hernesniemi J. Microscope-integrated near-infrared indocyanine green videoangiography during surgery of intracranial aneurysms: the Helsinki experience. Surg Neurol. 2009; 71:543–50; discussion 550

Wang C, Hsu SK, Chang CJ, Chen MH, Huang CT, Huang JS, Su IC. Transfemoral Approach for Intraoperative Angiography in the Prone or Three-quarter Prone Position : A Revisited Protocol for Intracranial Arteriovenous Malformation and Fistula Surgery. Clin Neuroradiol. 2019 Apr 29. doi: 10.1007/s00062-019-00783-3. [Epub ahead of print] PubMed PMID: 31037364.

Durner G, Wahler H, Braun M, Kapapa T, Wirtz CR, König R, Pala A. The value of intraoperative angiography in the time of indocyanine green videoangiography in the treatment of cerebrovascular lesions: Efficacy, workflow, risk-benefit and cost analysis A prospective study. Clin Neurol Neurosurg. 2021 Apr 2;205:106628. doi: 10.1016/j.clineuro.2021.106628. Epub ahead of print. PMID: 33895619.

Olfactory groove schwannoma

Olfactory Groove Schwannoma: A Rare Intracranial Tumor – Case Studies and Review

Olfactory Groove Schwannoma Test

  1. What is the primary location of Olfactory Groove Schwannomas?
    1. [ ] a) Temporal lobe
    2. [x] b) Frontal lobe
    3. [ ] c) Occipital lobe
    4. [ ] d) Parietal lobe
  1. Which of the following is NOT a common symptom of Olfactory Groove Schwannoma?
    1. [ ] a) Anosmia
    2. [ ] b) Visual disturbances
    3. [x] c) Auditory hallucinations
    4. [ ] d) Headaches
  1. What is the primary treatment option for Olfactory Groove Schwannomas?
    1. [ ] a) Radiation therapy
    2. [ ] b) Chemotherapy
    3. [x] c) Surgical resection
    4. [ ] d) Medication
  1. Which of the following statements is true regarding Olfactory Groove Schwannomas?
    1. [x] a) They often originate from Schwann cells in the olfactory groove.
    2. [ ] b) They primarily affect the optic nerve.
    3. [ ] c) They are associated with frequent auditory deficits.
    4. [ ] d) They cannot be treated surgically.
  1. Olfactory Groove Schwannomas can sometimes be confused with which other tumors?
    1. [ ] a) Glioblastomas
    2. [x] b) Olfactory groove meningiomas
    3. [ ] c) Medulloblastomas
    4. [ ] d) Astrocytomas
  1. What is the typical outcome after complete surgical resection of an Olfactory Groove Schwannoma?
    1. [ ] a) Poor prognosis
    2. [ ] b) Neurological deficits
    3. [x] c) Favorable prognosis
    4. [ ] d) Olfactory dysfunction
  1. What is the primary goal of surgical resection in treating Olfactory Groove Schwannomas?
    1. [ ] a) Complete removal of the tumor with no concern for neurological function
    2. [x] b) Partial removal of the tumor while preserving neurological function
    3. [ ] c) Eliminating olfactory function
    4. [ ] d) None of the above
  1. According to the provided information, what is the controversial aspect of Olfactory Groove Schwannoma origin?
    1. [ ] a) They always originate from the olfactory nerve.
    2. [x] b) Their origin remains unknown.
    3. [ ] c) They originate from the optic nerve.
    4. [ ] d) They develop due to hormonal imbalances.
  1. In which cranial fossa are Olfactory Groove Schwannomas predominantly located?
    1. [ ] a) Middle cranial fossa
    2. [ ] b) Posterior cranial fossa
    3. [x] c) Anterior cranial fossa
    4. [ ] d) Inferior cranial fossa
  1. Which specific cells are responsible for the formation of Schwannomas?
    1. [ ] a) Oligodendrocytes
    2. [x] b) Schwann cells
    3. [ ] c) Neurons
    4. [ ] d) Astrocytes

Olfactory groove schwannoma is an uncommon intracranial tumor originating in the olfactory groove and is primarily associated with benign schwann cells. This review aims to provide insights into the clinical characteristics, diagnosis, treatment, and prognosis of this rare entity. Olfactory groove schwannomas are predominantly located in the anterior cranial fossa, often resulting in symptoms such as headaches, anosmia, visual disturbances, personality changes, and cognitive deficits. Diagnosis typically involves neuroimaging studies like MRI and CT scans. Surgical resection is the primary treatment option, with the goal of preserving neurological function, and sometimes complemented with radiation therapy for inoperable cases. While olfactory groove schwannomas are generally benign, each case presents unique challenges, and a multidisciplinary approach is essential for comprehensive patient care. Additionally, there is an ongoing debate about their origin, with both developmental and non-developmental hypotheses being proposed. Differential diagnosis should consider other tumors, such as olfactory groove meningiomas and esthesioneuroblastomas. This review also discusses case reports to shed light on the complex nature of olfactory groove schwannomas. Understanding the diverse aspects of this rare tumor is crucial for accurate diagnosis, management, and patient outcomes.

Keywords: Olfactory groove schwannomaanterior cranial fossadiagnosissurgical resectionprognosisdifferential diagnosiscase reports.

Olfactory groove schwannoma is a rare type of tumor that arises in the olfactory groove of the skull. Schwannomas are typically benign tumors that originate from Schwann cells, which are responsible for the formation of the myelin sheath covering nerves. When a schwannoma develops in the olfactory groove, it usually arises from the olfactory nerve or its branches.

Here are some key points about olfactory groove schwannomas:

Location: Olfactory groove schwannomas are found in the anterior cranial fossa, where the olfactory bulb and tract are located. They can grow and compress nearby structures, including the frontal lobes of the brain.

Symptoms: The symptoms of an olfactory groove schwannoma can vary depending on its size and location. Common symptoms may include headaches, changes in smell (anosmia), visual disturbances, personality changes, and cognitive deficits.

Diagnosis: Diagnosis often involves neuroimaging studies, such as magnetic resonance imaging (MRI) or computed tomography (CT) scans. These tests can help visualize the tumor and its impact on adjacent structures.

Treatment: The primary treatment for olfactory groove schwannomas is surgical resection. The goal of surgery is to remove the tumor while preserving neurological function. In some cases, a combination of microsurgery and endoscopy may be used to access and remove the tumor. Radiation therapy may be considered for residual or inoperable tumors.

Prognosis: Olfactory groove schwannomas are typically slow-growing and benign, which generally results in a favorable prognosis after surgical removal. The long-term outcome depends on factors such as the extent of tumor resection and the patient’s overall health.

Differential Diagnosis: Olfactory groove schwannomas may be mistaken for other tumors, such as olfactory groove meningiomas, which are more common in this region. A precise diagnosis is essential for determining the most appropriate treatment plan.

Multidisciplinary Approach: Managing olfactory groove schwannomas often requires a multidisciplinary approach involving neurosurgeons, otolaryngologists, and neurologists to provide comprehensive care.

It’s important to note that while olfactory groove schwannomas are generally benign, each case is unique, and treatment decisions should be made in consultation with a medical team specializing in neurosurgery and neuro-oncology.

According to past reports, subfrontal schwannomas are occasionally described as olfactory schwannomas or olfactory groove schwannomas.

Schwannoma arising from the olfactory system, often called olfactory groove schwannoma (OGS), is rare, as the olfactory bulb and tract, belonging to the central nervous system, should lack Schwann cells. Another rare entity called olfactory ensheathing cell tumor (OECT) has been reported, which mimics clinical and radiological characteristics of OGS.

They are very rare tumors, leaving the issue of their origin controversial.

In 94 patients with anterior skull base (ASB) and sinonasal schwannomas, 44 (46.8%) were exclusively sinonasal, 30 cases (31.9%) were exclusively intracranial, 12 (12.8%) were primarily intracranial with extension into the paranasal sinuses, and 8 (8.5%) were primarily sinonasal with intracranial extension 1).

Li et al. gathered previous literatures and reported that results in 35 cases of olfactory schwannomas (between 1974 and 2010) has shown that 14 out of 30 cases (47%) (with the exclusion of five cases due to unknown olfactory function) had preserved olfactory function, but that the remaining 16 (53%) experienced either anosmia or hyposmia. Regarding the attachment sites of the schwannomas, they summarized that 12 cases were on the cribriform plate, 10 cases were on the olfactory groove, and 5 cases were on the skull base and skull base dura. When the tumor was attached to the cribriform plate, the rate of olfaction preservation was relatively high [9 of 11 cases (82%), excluding one case due to unknown olfactory function], compared to olfactory groove attachment [2 of 7 cases (29%), excluding three cases due to unknown olfactory function].

Figueiredo et al. systematically reviewed the literature concerning the anterior cranial fossa schwannomas to understand their pathogenesis, determine their origin, and standardize the terminology. They performed a MEDLINE, EMBASE, and Science Citation Index Expanded search of the literature; age, gender, clinical presentation, presence or absence of hyposmia, radiological features, and apparent origin were analyzed and tabulated. Cases in a context of neurofibromatosis and nasal schwannomas with intracranial extension were not included. Age varied between 14 and 63 years (mean = 30.9). There were 22 male and 11 female patients. The clinical presentation included seizures (n = 15), headache (n = 16), visual deficits (n = 7), cognitive disturbances (n = 3), and rhinorrhea (n = 1). Hyposmia was present in 14 cases, absent in 13 cases (39.3%), and unreported in five. Homogeneous and heterogeneous contrast enhancement was observed in 14 and 15 cases, respectively. The region of the olfactory groove was the probable site in 96.5%. Olfactory tract could be identified in 39.3%. The most probable origin is the meningeal branches of trigeminal nerve or anterior ethmoidal nerves. Thus, olfactory groove schwannoma would better describe its origin and pathogenesis and should be the term preferentially used to name it 2).

Because the olfactory and optic nerves lack a Schwann cell layer, these are not prone to develop into a schwannoma.

Some hypotheses about the genesis of olfactory groove schwannoma are centered on its developmental and non-developmental origins.

The developmental hypotheses suggest whether mesenchymal pial cells to transform into ectodermal Schwann cells or neural crest cells to migrate within the substance of the central nervous system .

The non-developmental hypotheses postulate that intracranial schwannomas arise from the Schwann cells normally presenting in the adjacent structures, such as the perivascular nerve plexus, the meningeal branches of the trigeminal and anterior ethmoidal nerves innervating the anterior cranial fossa and olfactory groove 3) 4).

Yasuda et al. 5) proposed the concept of an olfactory ensheathing cell (OEC) tumor in 2006. Olfactory ensheathing cells are glial cells that ensheath the axons of the first cranial nerve. Microscopically, both olfactory ensheathing cells and Schwann cells have similar morphological and immunohistochemical features. However, immunohistochemically olfactory ensheathing cells are negative for Leu7 and Schwann cells positive 6).

Often, these tumors can be confused for other entities, especially olfactory groove meningiomas and esthesioneuroblastoma7).

Because most olfactory region schwannomas have a benign nature, a complete resection of the tumor is the treatment of choice, and adjunctive therapy is not usually required 8) 9).

With the recent advances in endoscopic skull base surgery, various anterior skull base tumors (ASB) can be resected successfully using an expanded endoscopic endonasal transcribriform approach through a “keyhole craniectomy” in the ventral skull base. This approach represents the most direct route to the anterior cranial base without any brain retraction. Tumor involving the paranasal sinuses, medial orbits, and cribriform plate can be readily resected. In a video atlas report, Liu and Eloy demonstrate their step-by-step techniques for resection of an ASB olfactory schwannoma using a purely endoscopic endonasal transcribriform approach. They describe and illustrate the operative nuances and surgical pearls to safely and efficiently perform the approach, tumor resection, and multilayered reconstruction of the cranial base defect. The video can be found here: http://youtu.be/NLtOGfKWC6U 10).

Endoscopic Endonasal Anterior Cranial Fossa Approach 11)

The prognosis after complete resection is known to be favorable 12).

When the tumor is attached to the cribriform plate, the preservation rate of olfactory function is higher compared to nearby structures 13).

A 65-year-old male patient who presented with olfactory groove meningioma and non-functioning pituitary adenoma as a collision tumor. The patient was admitted with a headache and right-sided vision loss. The patient’s first neurologic examination was consistent with temporal anopsia in the right eye. Subsequent contrast-enhanced cranial MRI revealed a 65x55x40 mm heterogeneously contrast-enhanced lesion in the anterior skull base extending from the sellar region to the corpus callosum. Because of the tumor size, a two-staged operation was planned. First, the tumor was partially excised via a right frontal craniotomy with a transcranial approach, and the tumor in the sellar region was left as a residue. The pathology reports after the first surgery showed pituitary adenoma and meningeal epithelial type meningioma (WHO Grade I). The residual tumor tissue was resected seven months later via an endoscopic endonasal approach, except for the part that invaded the right anterior cerebral artery. The optic nerve was decompressed. The patient was then referred to the radiation oncology clinic for radiosurgery. Collision tumors should be considered in the differential diagnosis in preoperative evaluation and surgical planning when heterogeneously contrast-enhanced areas significantly localized adjacent to each other are seen on cranial MRI. On the other hand, when the surgeon encounters sudden changes in the appearance or consistency of the tumor during the surgery, they should suspect these tumor complexes. The diagnosis of collision tumors is quite challenging but is of great importance regarding the patient’s need for postoperative radiation therapy or the recurrence characteristics of tumors. However, more studies are needed on these complexes’ etiology, surgical planning, and postoperative management 14).

A 59-year-old woman who presented with a paroxysmal headache for 1 year. The tumor appeared as hypointensity on T1-weighted images, hyperintensity on T2-weighted, and exhibited strong, heterogeneous enhancement. The tumor was removed through a lateral supraorbital approach. The final pathologic diagnosis was schwannoma. The postoperative period was uneventful after 4 months, and the headache disappeared 15).


Bohoun et al report two rare cases of schwannoma-like tumor in the anterior cranial fossa that showed negative staining for Leu7, but positive staining for Schwann/2E, and discuss their origin. Two cases of mass lesions in the anterior cranial fossa in a 26-year-old man and a 24-year-old woman were successfully removed. Morphological examination of these tumors was compatible with a diagnosis of schwannoma. Immunohistochemically, both cases were negative for Leu7, yielding a diagnosis of olfactory ensheathing cell tumor (OECT), but were positive for the schwannoma-specific marker, Schwann/2E. Immunohistochemical staining results in this two cases question the current assumption that OGS and OECT can be distinguished only by Leu7 staining pattern. In conclusion, the origins of OGS and OECT remain to be determined, and further studies in larger numbers of cases are needed to characterize these rare tumors in the anterior cranial fossa 16)


A case of a 49-year-old woman with an olfactory groove schwannoma attached to the cribriform plate without olfactory dysfunction. She had no specific neurological symptoms other than a headache, and resection of the tumor showed it to be a schwannoma. About 19 months after the operation, a follow-up MRI showed no evidence of tumor recurrence. Surgical resection through subfrontal approach could be one of the curative modality in managing an olfactory groove schwannoma. An olfactory groove schwannoma should be considered in the differential diagnosis of anterior skull base tumors 17).


Okamoto et al. report two cases of subfrontal schwannomas treated with surgical resection. In one case, the tumor was located between the endosteal and meningeal layers of the dura mater. This rare case suggests that subfrontal schwannomas may originate from the fila olfactoria 18).

A 24 year old lady presented with hemifacial paraesthesias. Radiology revealed a large olfactory region enhancing lesion. She was operated through a transbasal approach with olfactory preservation. 19).

One patient had intradural intracranial extension and required an extended endoscopic endonasal transcribriform approach with anterior skull base resection 20).


A 66-year-old woman presented with a 1-year history of progressive headaches. Clinical examination revealed hypoesthesia of the nasal tip. CT-scan and MRI studies revealed a large subfrontal tumor thought preoperatively to be a meningioma. Intraoperatively, a large extra-axial tumor arising from the floor of the right frontal fossa was encountered. Histopathology identified the tumor as a schwannoma. This current case gives strong clinical presumption of an origin from the anterior ethmoidal nerve. We reviewed the literature in order to establish the epidemiology of these tumors, from which there appear to be divergent profiles depending on tumor origin and histology. Despite close similarities with olfactory groove meningiomas, patient history and radiological findings provide substantial evidence for differential diagnosis 21).


Liu and Eloy demonstrate their step-by-step techniques for resection of an ASB olfactory schwannoma using a purely endoscopic endonasal transcribriform approach.

A case of schwannoma arising from the olfactory groove in a 16-year-old girl who presented with generalized seizures without olfactory dysfunction or other neurologic deficits. Computerized tomography (CT) scan showed a large mass with abundant calcification located in the olfactory groove, which was confirmed as a schwannoma by histology and totally resected via basal subfrontal approach.

The tumor was attached to the cribriform plate, and achieved gross total resection without compromising her olfactory function 22).

In conclusion, understanding the diverse aspects of olfactory groove schwannomas is crucial for accurate diagnosis, effective management, and improved patient outcomes. This rare tumor entity serves as a reminder of the complexity of intracranial pathologies and the need for ongoing research to better comprehend its origin and pathogenesis.


Sunaryo PL, Svider PF, Husain Q, Choudhry OJ, Eloy JA, Liu JK. Schwannomas of the sinonasal tract and anterior skull base: a systematic review of 94 cases. Am J Rhinol Allergy. 2014 Jan-Feb;28(1):39-49. doi: 10.2500/ajra.2014.28.3978. Review. PubMed PMID: 24717879.

Figueiredo EG, Soga Y, Amorim RL, Oliveira AM, Teixeira MJ. The puzzling olfactory groove schwannoma: a systematic review. Skull Base. 2011 Jan;21(1):31-6. doi: 10.1055/s-0030-1262945. PubMed PMID: 22451797; PubMed Central PMCID: PMC3312416.

Shenoy SN, Raja A. Cystic olfactory groove schwannoma. Neurol India. 2004;52:261–262.

Li YP, Jiang S, Zhou PZ, Ni YB. Solitary olfactory schwannoma without olfactory dysfunction: a new case report and literature review. Neurol Sci. 2012;33:137–142.

Yasuda M, Higuchi O, Takano S, Matsumura A. Olfactory ensheathing cell tumor: a case report. J Neurooncol. 2006;76:111–113.

Yamaguchi T, Fujii H, Dziurzynski K, Delashaw JB, Watanabe E. Olfactory ensheathing cell tumor: case report. Skull Base. 2010 Sep;20(5):357-61. doi: 10.1055/s-0030-1249572. PubMed PMID: 21359000; PubMed Central PMCID: PMC3023328.

Khandwala K, Alam MM, Ashfaq Z, Hilal K. Olfactory schwannoma masquerading as esthesioneuroblastoma. BMJ Case Rep. 2023 Oct 18;16(10):e257847. doi: 10.1136/bcr-2023-257847. PMID: 37852667.

Carron JD, Singh RV, Karakla DW, Silverberg M. Solitary schwannoma of the olfactory groove: case report and review of the literature. Skull Base. 2002;12:163–166.
9) , 12)

Choi YS, Sung KS, Song YJ, Kim HD. Olfactory schwannoma-case report- J Korean Neurosurg Soc. 2009;45:103–106.

Liu JK, Eloy JA. Expanded endoscopic endonasal transcribriform approach for resection of anterior skull base olfactory schwannoma. J Neurosurg. 2012 Jan;32 Suppl:E3. PubMed PMID: 22251251.

Candelo E, Otamendi-Lopez A, Chaichana KL, Donaldson AM. Endoscopic Endonasal Anterior Cranial Fossa Approach for Rare Giant Olfactory Schwannoma Resection. Oper Neurosurg (Hagerstown). 2023 Sep 25. doi: 10.1227/ons.0000000000000921. Epub ahead of print. PMID: 37747334.
13) , 17)

Kim DY, Yoon PH, Kie JH, Yang KH. The olfactory groove schwannoma attached to the cribriform plate: a case report. Brain Tumor Res Treat. 2015 Apr;3(1):56-9. doi: 10.14791/btrt.2015.3.1.56. Epub 2015 Apr 29. PubMed PMID: 25977910; PubMed Central PMCID: PMC4426280.

Aydin MV, Yangi K, Toptas E, Aydin S. Skull Base Collision Tumors: Giant Non-functioning Pituitary Adenoma and Olfactory Groove Meningioma. Cureus. 2023 Sep 5;15(9):e44710. doi: 10.7759/cureus.44710. PMID: 37809125; PMCID: PMC10552590.

Guo W, Liu Z, Wang Z, Tian H, Zi X. Olfactory Groove Schwannoma or Olfactory Ensheathing cell Tumor? J Craniofac Surg. 2023 Aug 29. doi: 10.1097/SCS.0000000000009705. Epub ahead of print. PMID: 37643126.

Bohoun CA, Terakawa Y, Goto T, Tanaka S, Kuwae Y, Ohsawa M, Morisako H, Nakajo K, Sato H, Ohata K, Yokoo H. Schwannoma-like tumor in the anterior cranial fossa immunonegative for Leu7 but immunopositive for Schwann/2E. Neuropathology. 2016 Dec 7. doi: 10.1111/neup.12357. [Epub ahead of print] PubMed PMID: 27925298.

Okamoto H, Mineta T, Wakamiya T, Tsukamoto H, Katsuta T, Nakagaki H, Matsushima T. Two cases of subfrontal schwannoma, including a rare case located between the endosteal and meningeal layers of the dura. Neurol Med Chir (Tokyo). 2014;54(8):681-5. Epub 2013 Dec 5. PubMed PMID: 24305023.

Salunke P, Patra DP, Futane S, Nada R. Olfactory region schwannoma: Excision with preservation of olfaction. J Neurosci Rural Pract. 2014 Jul;5(3):281-3. doi: 10.4103/0976-3147.133600. PubMed PMID: 25002774; PubMed Central PMCID: PMC4078619.

Blake DM, Husain Q, Kanumuri VV, Svider PF, Eloy JA, Liu JK. Endoscopic endonasal resection of sinonasal and anterior skull base schwannomas. J Clin Neurosci. 2014 Aug;21(8):1419-23. doi: 10.1016/j.jocn.2014.03.007. Epub 2014 May 5. PubMed PMID: 24810934.

Sauvaget F, François P, Ben Ismail M, Thomas C, Velut S. Anterior fossa schwannoma mimicking an olfactory groove meningioma: case report and literature review. Neurochirurgie. 2013 Apr;59(2):75-80. doi: 10.1016/j.neuchi.2013.02.003. Epub 2013 Apr 13. Review. PubMed PMID: 23587626.

Li YP, Jiang S, Zhou PZ, Ni YB. Solitary olfactory schwannoma without olfactory dysfunction: a new case report and literature review. Neurol Sci. 2012 Feb;33(1):137-42. doi: 10.1007/s10072-011-0573-9. Epub 2011 Apr 12. Review. Erratum in: Neurol Sci. 2012 Feb;33(1):217. PubMed PMID: 21484358; PubMed Central PMCID: PMC3275737.

Anterior communicating artery aneurysm 

Anterior communicating artery aneurysm


Deep Transcranial magnetic stimulation for obsessive-compulsive disorder treatment

Deep Transcranial magnetic stimulation for obsessive-compulsive disorder treatment

  1. What is the main target region in the brain for dTMS when treating OCD?
    1. A. Temporal lobe
    2. B. Prefrontal cortex
    3. C. Anterior cingulate cortex (ACC)
    4. D. Occipital lobe
  1. What is the proposed mechanism of action for dTMS in the treatment of OCD?
    1. A. Regulating sleep patterns
    2. B. Modulating brain activity in the prefrontal cortex
    3. C. Enhancing sensory perception
    4. D. Modulating brain activity in the ACC to reduce obsessive thoughts and compulsive behaviors
  1. How is a typical dTMS treatment protocol for OCD structured?
    1. A. One session per month
    2. B. Multiple sessions administered in a single day
    3. C. Multiple sessions administered over several weeks
    4. D. Single session with high intensity
  1. What are some common side effects associated with dTMS treatment for OCD?
    1. A. Nausea and dizziness
    2. B. Severe and long-lasting headaches
    3. C. Mild discomfort or temporary headache at the stimulation site
    4. D. Memory loss and visual disturbances
  1. In terms of efficacy, what have research findings on dTMS for OCD shown?
    1. A. Consistently significant benefits for all individuals
    2. B. No impact on OCD symptoms
    3. C. Mixed results with some individuals experiencing a reduction in symptoms
    4. D. A complete cure for OCD
  1. Why is individualized treatment evaluation important when considering dTMS as a treatment option for OCD?
    1. A. To determine the color of the treatment device
    2. B. To streamline the treatment process
    3. C. To ensure a one-size-fits-all approach
    4. D. Because the effectiveness of dTMS varies from person to person
  1. Who conducted a study to evaluate the current research on the effectiveness of dTMS therapy for individuals with treatment-resistant OCD?
    1. A. Dr. John Smith
    2. B. Dr. Emily Johnson
    3. C. McCathern et al.
    4. D. Roth et al.
  1. In a study by Smárason et al., what was the primary focus regarding the relationship between dTMS and OCD symptoms?
    1. A. The impact of dTMS on anxiety symptoms
    2. B. The relationship between dTMS and depression symptoms
    3. C. The impact of dTMS on sleep patterns
    4. D. The effects of dTMS on cognitive functioning
  1. What was the conclusion of the study by Smárason et al. regarding the impact of dTMS on depression symptoms during the treatment of OCD?
    1. A. dTMS significantly worsened depression symptoms
    2. B. dTMS had no effect on depression symptoms
    3. C. dTMS significantly improved depression symptoms
    4. D. Changes in depression symptoms were unpredictable
  1. In a case series by Ikawa et al., what was the response rate to dTMS treatment for OCD, and what were the key findings in terms of symptom improvements?
    1. A. 100% response rate; no symptom improvements observed
    2. B. 75% response rate; moderate symptom improvements
    3. C. 53.9% response rate; significant improvements in Yale-Brown Obsessive Compulsive Scale (Y-BOCS) scores
    4. D. 30% response rate; slight symptom improvements

—- Answers:

C. Anterior cingulate cortex (ACC)

D. Modulating brain activity in the ACC to reduce obsessive thoughts and compulsive behaviors

C. Multiple sessions administered over several weeks

C. Mild discomfort or temporary headache at the stimulation site

C. Mixed results with some individuals experiencing a reduction in symptoms

D. Because the effectiveness of dTMS varies from person to person

C. McCathern et al.

B. The relationship between dTMS and depression symptoms

D. Changes in depression symptoms were unpredictable

C. 53.9% response rate; significant improvements in Yale-Brown Obsessive Compulsive Scale (Y-BOCS) scores

Deep Transcranial Magnetic Stimulation (dTMS) has been explored as a potential treatment for Obsessive-Compulsive Disorder (OCD). OCD is a mental health condition characterized by recurrent, distressing obsessions and repetitive, often ritualistic compulsions. While conventional treatments such as cognitive-behavioral therapy and medication are effective for many individuals with OCD, some people do not respond adequately or experience significant side effects. This has led to the investigation of alternative approaches, including dTMS.

Here are some key points regarding dTMS for OCD treatment:

Targeted Brain Regions: In the context of OCD treatment, dTMS typically targets the anterior cingulate cortex (ACC), a brain region associated with the regulation of cognitive and emotional processes. Dysfunction in this area is believed to play a role in the development and persistence of OCD symptoms.

Mechanism of Action: The idea behind dTMS for OCD is to modulate brain activity in the ACC and normalize its functioning. By applying magnetic pulses to this region, the hope is to reduce obsessive thoughts and compulsive behaviors.

Treatment Protocol: A typical dTMS treatment protocol for OCD involves multiple sessions administered over several weeks. The specific parameters, such as the frequency, intensity, and duration of each session, will be determined by the healthcare provider based on the patient’s needs and response to treatment.

Safety and Side Effects: dTMS is generally considered safe with relatively mild side effects, such as mild discomfort or headache at the stimulation site. These side effects are typically temporary and well-tolerated. However, the treatment should be administered by trained professionals to ensure safety and effectiveness.

Efficacy: Research on the use of dTMS for OCD is still evolving, and the results have been mixed. Some studies have shown promising outcomes, with a reduction in OCD symptoms, while others have not demonstrated significant benefits. Response to dTMS can vary among individuals.

Individualized Treatment: The effectiveness of dTMS for OCD, like other treatment options, can vary from person to person. The suitability of dTMS as a treatment for a specific individual should be determined through a comprehensive evaluation by a qualified mental health professional.

McCathern et al. evaluate the current research on the effectiveness of dTMS therapy for individuals with treatment-resistant OCD. This review also investigates shortcomings in current dTMS research and the hypothesized future of dTMS therapy 1)

Roth et al. analyzed data from a double-blind multicenter dTMS study and found the efficacy of this novel treatment even in OCD patient cohorts who previously failed to respond to multiple medications and CBT 2).

Whether dTMS affects depression symptoms similarly to cognitive behavioral therapy (CBT) remains to be examined.

The study employed a random intercept cross-lagged panel model (RI-CLPM) to examine the relationship of OCD and depression symptoms in 94 treatment-refractory patients, undergoing dTMS or sham treatment.

Both OCD and depression symptoms improved significantly. However, a stable, cross-lagged relationship between the variables was not supported. Changes in one symptom domain could not be used to predict the other.

The present study was conducted in a treatment-refractory population, meaning the present findings may not generalize to treatment patients or those with less severe OCD symptoms. It is unclear whether the study was sufficiently powered to detect the effects of interest, and this concern also meant that examining the dTMS and sham groups independently was not feasible.

When treating OCD with dTMS, depression symptoms appear likely to diminish but should be monitored throughout, and additional interventions applied if needed 3).

The study provides valuable insights into the potential benefits of dTMS for treatment-refractory patients with OCD and comorbid depression symptoms. However, it also highlights limitations related to generalizability and statistical power, emphasizing the need for further research to better understand the interplay between OCD and depression symptoms in various patient populations. Additionally, it underscores the importance of ongoing monitoring and a holistic approach to mental health treatment.

Ikawa et al. conducted an FDA-approved dTMS protocol for 26 patients with OCD. In addition, individual exposure stimulation that elicited each patient’s obsessive thoughts was also combined during dTMS treatment. Before and after 30 sessions of TMS treatment, the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) was used to assess changes in the severity of each patient’s obsessive-compulsive disorder. Response to dTMS treatment in patients with OCD was determined by whether the total score on the Y-BOCS after a course of treatment was reduced by 30% or more compared with the score at baseline. The percentage of responders in this case series following the 30 sessions of dTMS treatment was 53.9%. In addition, total Y-BOCS scores and scores on each item were significantly improved. The percent changes in total Y-BOCS scores did not differ between the sexes or between on- and off-medication patients. No obvious adverse events were observed in this case series. In line with the results of TMS studies for OCD patients reported overseas, dTMS treatment for Japanese patients with OCD may have a favorable therapeutic effect 4)

The study conducted by Ikawa et al. presents promising results for the use of dTMS in the treatment of OCD. The response rate, improvements in Y-BOCS scores, and the absence of adverse events are positive indicators. However, further research with larger sample sizes, control groups, and long-term follow-up is needed to confirm the efficacy of dTMS for OCD and to understand its place in the broader spectrum of OCD treatments.


McCathern AG, Mathai DS, Cho RY, Goodman WK, Storch EA. Deep transcranial magnetic stimulation for obsessive compulsive disorder. Expert Rev Neurother. 2020 Oct;20(10):1029-1036. doi: 10.1080/14737175.2020.1798232. Epub 2020 Aug 1. PMID: 32684005.

Roth Y, Barnea-Ygael N, Carmi L, Storch EA, Tendler A, Zangen A. Deep transcranial magnetic stimulation for obsessive-compulsive disorder is efficacious even in patients who failed multiple medications and CBT. Psychiatry Res. 2020 Aug;290:113179. doi: 10.1016/j.psychres.2020.113179. Epub 2020 Jun 3. PMID: 32540588.

Smárason O, Boedeker PJ, Guzick AG, Tendler A, Sheth SA, Goodman WK, Storch EA. Depressive symptoms during deep transcranial magnetic stimulation or sham treatment for obsessive-compulsive disorder. J Affect Disord. 2023 Oct 16:S0165-0327(23)01257-0. doi: 10.1016/j.jad.2023.10.075. Epub ahead of print. PMID: 37852581.

Ikawa H, Osawa R, Sato A, Mizuno H, Noda Y. A Case Series of Deep Transcranial Magnetic Stimulation Treatment for Patients with Obsessive-Compulsive Disorder in the Tokyo Metropolitan Area. J Clin Med. 2022 Oct 18;11(20):6133. doi: 10.3390/jcm11206133. PMID: 36294453; PMCID: PMC9605577.

Carotid cavernous fistula coil embolization

Carotid cavernous fistula coil embolization

Carotid cavernous fistula (CCF) coil embolization is a crucial medical procedure designed to address the abnormal connection between the carotid artery and the cavernous sinus, often resulting in abnormal blood flow and elevated pressure within the cavernous sinus. This connection can lead to various neurological symptoms and potential complications.

This review discusses the key steps involved in CCF coil embolization, including diagnostic angiography, guidewire placement, catheter insertion, coil placement, and post-procedure monitoring. The primary objective of this procedure is to effectively close the abnormal connection, restoring normal blood flow and alleviating CCF-related symptoms.

Furthermore, the review highlights complications associated with different venous approaches, such as cranial nerve injury, vascular dissections, and perforations. It emphasizes the significance of careful patient selection and technique to minimize these complications.

The use of detachable balloons in the treatment of direct CCFs is also explored, providing insights into their role in achieving successful embolization. Clinical outcomes and angiographic cure rates are discussed based on case series and reports, offering valuable information for healthcare practitioners and researchers.

In conclusion, carotid cavernous fistula coil embolization is an essential intervention performed by specialized medical professionals. This review provides a comprehensive overview of the procedure, its complications, and outcomes, facilitating a better understanding of the treatment and its effectiveness in managing CCF.

Carotid cavernous fistula (CCF) coil embolization is a medical procedure used to treat a carotid cavernous fistula, which is an abnormal connection between the carotid artery and the cavernous sinus in the brain. This connection can lead to abnormal blood flow and pressure in the cavernous sinus, which can cause a range of neurological symptoms and potential complications.

The goal of coil embolization is to close off the abnormal connection between the carotid artery and the cavernous sinus, thus restoring normal blood flow and relieving the symptoms associated with the CCF. Here’s how the procedure typically works:

Diagnostic Angiography: The first step is usually a diagnostic angiography, during which a contrast dye is injected into the blood vessels, and X-ray imaging is used to visualize the blood vessels in the head and neck. This helps the medical team locate the exact site of the CCF and assess its size and characteristics.

Guidewire Placement: A thin, flexible guidewire is threaded through a catheter and advanced through the blood vessels to reach the site of the CCF.

Catheter Insertion: A catheter, which is a long, thin tube, is then inserted into the blood vessel and guided to the location of the CCF.

Coil Placement: Platinum coils or other embolic devices are delivered through the catheter to the site of the CCF. These coils are designed to create a barrier that blocks the abnormal blood flow and encourages the formation of a blood clot to seal off the fistula.

Check and Repeat: The medical team will use imaging, typically fluoroscopy, to ensure that the coils are properly placed and that the CCF is effectively blocked. In some cases, additional coils may be needed to achieve complete closure.

Removal of Catheter: Once the CCF is successfully embolized, the catheter and guidewire are removed from the blood vessels.

Post-procedure Monitoring: After the procedure, patients are typically observed in a recovery area and monitored for a period to check for any immediate complications. They may also receive anticoagulant medications to prevent clot formation at the coil site.

Recovery time and the specific details of the procedure can vary depending on the individual case and the severity of the CCF. Patients may need to stay in the hospital for a period of observation, and they will be closely monitored for potential complications. Long-term follow-up is essential to assess the effectiveness of the coil embolization and to ensure that the CCF does not reoccur.

It’s important to note that this procedure is performed by interventional radiologists or neurosurgeons with expertise in vascular malformations, and the choice of treatment method depends on the specific characteristics of the CCF and the patient’s overall health.

Complications associated with different venous approaches are injury of the cranial nerves due to the dense packing of the CS with coils as well as vascular dissections and perforations 1).

One case (3.2%) experienced procedure-related complication presented with transient oculomotor nerve palsy 2)

The use of Onyx is not exempt from complications such as transient compressive neuropathies or cranial nerve ischemia/infarction caused by post-embolization CS thrombosis and penetration within arterial collaterals, respectively 3)

Acquired proptosis and progressive abducens nerve palsy due to overpacked coiling material: rare sequelae of carotid cavernous fistula embolization 4).

Plasencia and Santillan report ther experience using the endovascular technique in 24 patients harboring 25 CCFs treated between October 1994 and April 2010, with an emphasis on the role of detachable balloons for the treatment of direct CCFs.

Of the 16 patients who presented with direct CCFs (Barrow Type A CCFs) (age range, 7-62 years; mean age, 34.3 years), 14 were caused by traumatic injury and 2 by a ruptured internal carotid artery (ICA) aneurysm. Eight patients (age range, 32-71 years; mean age, 46.5 years) presented with nine indirect CCFs (Barrow Types B, C, and D). The clinical follow-up after endovascular treatment ranged from 2 to 108 months (mean, 35.2 months). In two cases (8%), the endovascular approach failed. Symptomatic complications related to the procedure occurred in three patients (12.5%): transient cranial nerve palsy in two patients and a permanent neurological deficit in one patient. Detachable balloons were used in 13 out of 16 (81.3%) direct CCFs and were associated with a cure rate of 92.3%. Overall, the angiographic cure rate was obtained in 22 out of 25 (88%) fistulas. Patients presenting with III nerve palsy improved gradually between 1 day and 6 months after treatment. Good clinical outcomes [modified Rankin scale (mRS) ≤ 2] were observed in 22 out of 24 (91.6%) patients at last follow-up 5)

Teoh et al. reported a acquired proptosis and progressive abducens nerve palsy due to overpacked coiling material: rare sequelae of carotid cavernous fistula embolization 6).

An 84-year-old woman presented to her local emergency room for diplopia and loss of visual acuity. Computed tomography (CT) of the head and CT angiography (CTA) showed no infarction, but the CTA revealed enlarged superior ophthalmic veins, suggesting a CCF (Figure 1). The emergency department referred her to Interventional Neuroradiology for treatment options. Physicians in the oculoplastics service also saw her before the procedure. Cerebral angiography was performed via the right femoral approach, demonstrating an indirect CCF supplied by small branches of both the right and left ICAs as well as ECA branches with primary venous drainage into the right superior ophthalmic vein. Immediately after the diagnosis of CCF was confirmed on diagnostic transfemoral arterial angiogram, a transfemoral venous approach was used in an attempt to treat the CCF via the jugular veins and the inferior petrosal sinus (IPS). This approach was unsuccessful because the IPS was completely occluded bilaterally. The patient returned for definitive treatment with the assistance of the ophthalmology department. In the angiography suite, the oculoplastic surgeon performed a cut down to expose the right superior ophthalmic vein.3 The neurointerventionalist then punctured the exposed vein with a micropuncture needle to advance an 0.018-inch guidewire into the cavernous sinus. A 4-French sheath was placed over the wire into the vein with its tip terminating at the midportion of the dilated superior ophthalmic vein. A Penumbra PX SLIM (Alameda, CA) microcatheter was then advanced over a microwire, and coils were used to occlude the cavernous sinus starting in the posterior cavernous sinus and extending forward into the superior and inferior ophthalmic veins. The neurointerventionalist deployed 150 cm of Penumbra 0.020-inch caliber detachable coils to occlude the CCF. During follow-up clinic visits, the patient’s vision showed continued improvement. Her visual acuity improved on postoperative day 1, and she showed further improvement on later clinic visits. Her diplopia slowly improved, and her proptosis also decreased. She had a cranial nerve VI palsy that improved by 50% at 3 months. Her chemosis resolved with treatment as well. 7).

What is the primary objective of carotid cavernous fistula (CCF) coil embolization?

a. To diagnose CCF-related symptoms b. To create an abnormal connection between the carotid artery and the cavernous sinus c. To close the abnormal connection between the carotid artery and the cavernous sinus d. To monitor blood flow within the cavernous sinus

Which of the following is NOT one of the key steps involved in CCF coil embolization?

a. Diagnostic angiography b. Guidewire placement c. Catheter insertion d. Direct intracranial surgery

What is the role of platinum coils or embolic devices in CCF coil embolization?

a. To diagnose the size of the CCF b. To block the abnormal blood flow and encourage blood clot formation c. To provide anticoagulant medications to patients d. To monitor the patient’s recovery

Why is post-procedure monitoring important in CCF coil embolization?

a. To assess the effectiveness of the coils b. To determine the size of the catheter c. To ensure the patient is comfortable during recovery d. To create a direct connection between the carotid artery and the cavernous sinus

What type of medical professionals typically perform CCF coil embolization?

a. General practitioners b. Cardiologists c. Interventional radiologists or neurosurgeons d. Ophthalmologists

Which of the following complications can be associated with CCF coil embolization?

a. Improved vision b. Cranial nerve injury c. Reduced blood pressure d. Normal blood flow in the cavernous sinus

What is the significance of detachable balloons in CCF coil embolization?

a. They are used to inflate the patient’s blood vessels. b. They help diagnose complications. c. They assist in achieving successful embolization. d. They are used to monitor cranial nerve function.

What is the purpose of a comprehensive review of CCF coil embolization?

a. To create a detailed treatment plan for patients b. To assess the cost of the procedure c. To provide a thorough examination of existing literature on the topic d. To promote awareness of CCF coil embolization among the public


c. To close the abnormal connection between the carotid artery and the cavernous sinus d. Direct intracranial surgery b. To block the abnormal blood flow and encourage blood clot formation a. To assess the effectiveness of the coils c. Interventional radiologists or neurosurgeons b. Cranial nerve injury c. They assist in achieving successful embolization. c. To provide a thorough examination of existing literature on the topic


Oishi H, Arai H, Sato K, Iizuka Y. Complications associated with transvenous embolisation of cavernous dural arteriovenous fistula. Acta Neurochir (Wien). 1999;141(12):1265-71. doi: 10.1007/s007010050429. PMID: 10672296.

Ma Y, Li Z, Zhang T, Chen H, Chen X, Zhao W. Efficiency of endovascular management with a combination of Onyx and coils for direct and indirect carotid cavernous fistula treatment: Experience of a single center. Clin Neurol Neurosurg. 2023 May;228:107700. doi: 10.1016/j.clineuro.2023.107700. Epub 2023 Mar 27. PMID: 36996671.

Elhammady MS, Wolfe SQ, Farhat H, Moftakhar R, Aziz-Sultan MA. Onyx embolization of carotid-cavernous fistulas. J Neurosurg. 2010 Mar;112(3):589-94. doi: 10.3171/2009.6.JNS09132. PMID: 19591548.
4) , 6)

Teoh RJJ, Ain Masnon N, Bahari NA, Ch’ng LS. Acquired proptosis and progressive abducens nerve palsy due to overpacked coiling material: rare sequelae of endovascular treatment for carotid cavernous fistula. BMJ Case Rep. 2023 Oct 10;16(10):e255406. doi: 10.1136/bcr-2023-255406. PMID: 37816571.

Plasencia AR, Santillan A. Endovascular embolization of carotid-cavernous fistulas: A pioneering experience in Peru. Surg Neurol Int. 2012;3:5. doi: 10.4103/2152-7806.92167. Epub 2012 Jan 21. PMID: 22363900; PMCID: PMC3279962.

Pansara A, Milburn JM, Perry M, Eubanks B. Clinical images – a quarterly column: transorbital coil embolization of a carotid cavernous fistula. Ochsner J. 2013 Fall;13(3):295-7. PMID: 24052755; PMCID: PMC3776501.