An intracranial succussion splash is a rare (occurring in ≈ 7%) but pathognomonic finding. Tension pneumocephalus may additionally cause signs and symptoms just as any mass (may cause focal deficit or increased ICP).
A minority of patients describe ‘bruit hydro-aerique’ (a splashing noise on head movement, equivalent to the succussion splash of pyloric stenosis) 3).
This noise may also be audible to the examiner with the aid of a stethoscope.
In a prospective observational study of patients undergoing craniotomy with dural opening. Eligible patients completed a questionnaire preoperatively and daily after surgery until discharge. Subjects were followed up at 14 days with a telephone consultation.
One hundred fifty-one patients with various pathologies were included. Of these, 47 (31 %) reported hearing sounds in their head, lasting an average 4-6 days (median, 4 days, mean, 6 days, range, 1-14 days). The peak onset was the first postoperative day and the most commonly used descriptors were ‘clicking’ [20/47 (43 %)] and ‘fluid moving’ in the head [9/47 (19 %)]. A significant proportion (42 %, 32/77) without a wounddrainage experienced intracranial sounds compared to those with a drain (20 %, 15/74, p < 0.01); there was no difference between suction and gravity drains. Approximately a third of the patients in both groups (post-craniotomy sounds group: 36 %, 17/47; group not reporting sounds: 31 %, 32/104), had postoperative CT scans for unrelated reasons: 73 % (8/11) of those with pneumocephalus experienced intracranial sounds, compared to 24 % (9/38) of those without pneumocephalus (p < 0.01). There was no significant association with craniotomy site or size, temporal bone drilling, bone flap replacement, or filling of the surgical cavity with fluid.
Sounds in the head after cranial surgery are common, affecting 31 % of patients. This is the first study into this subject, and provides valuable information useful for consenting patients. The data suggest pneumocephalus as a plausible explanation with which to reassure patients, rather than relying on anecdotal evidence, as has been the case to date 4).
Rapid neurologic deterioration following craniofacial resection may be caused by the development of tension pneumocephalus5).
Kim TK, Yoon JR, Kim YS, Choi Y, Han S, Jung J, Park IS. Pneumocephalus and headache following craniotomy during the immediate postoperative period. BMC Surg. 2022 Jun 29;22(1):252. doi: 10.1186/s12893-022-01701-0. PMID: 35768812.
Markham JW. The clinical features of pneumocephalus based upon a survey of 284 cases with report of 11 additional cases. Acta Neurochir (Wien). 1967;16(1):1-78. PubMed PMID: 6032371.
Sivasubramaniam V, Alg VS, Frantzias J, Acharya SY, Papadopoulos MC, Martin AJ. ‘Noises in the head’: a prospective study to characterize intracranial sounds after cranial surgery. Acta Neurochir (Wien). 2016 Aug;158(8):1429-35. doi: 10.1007/s00701-016-2872-7. Epub 2016 Jun 21. PubMed PMID: 27328839.
Accurate preoperativediagnosis is essential because they are highly vascular with a high tendency for intraoperative bleeding.
Management of aggressive VHs involves pre-op embolization, spinal surgery, and reconstruction. Pain management, physical rehabilitation, and close neurological follow-up are imperative to near-total recovery 1).
Surgery
Surgery is required in cases of rapid or progressive neurological symptoms like compressive myelopathy or radiculopathy.
Vertebral hemangioma resection can be a real challenge for spine surgeons, given the high potential of massive intraoperative bleeding. For this reason, preoperative transarterial embolization of this tumor is supported by the available literature 2).
A navigation-guided drill is highly helpful for real-time monitoring of ongoing tumor resection. It enables safely resection of the tumor, especially in the anterior cortical surface of the vertebral body, and easily resections even hard tumors. This method results in reducing residual tumors and maintaining safe resection 3).
Radiotherapy
Radiotherapy can be used in patients with slowly progressive neurological deficits.
CT guided alcohol injection
While CT-guided direct alcohol injection is effective in the management of symptomatic and aggressive vertebral hemangiomas, spinal angiography and trans-arterial embolization of the blood supply to the vertebral body hemangioma, prior to the direct transpedicular alcohol embolization of the lesion, improves the safety of the procedure 4).
Radiofrequency ablation
Other emerging options in cases of aggressive hemangiomas include radiofrequency ablation with a hemostatic agent (e.g. FLOSEAL, Baxter, USA), and bone autograft placement 5).
Minimally invasive procedures may be successful in smaller lesions 6).
Case reports
The case of a pregnancy who was diagnosed with an aggressive vertebral hemangioma that further led to progressive paraparesis. We had to take the fact that she was pregnant into account in the diagnostic procedure, the choice of examination method, and also the method of therapy. The goal of this case report is threefold: (1) provide an overview of the possible methods of management, specifically imaging, which will aid in diagnosis and based on that, (2) determine the appropriate therapy, and (3) review the risks and benefits of each will be presented when choosing individual approaches 7).
Goraya GS, Singhal S, Paul BS, Paul G. Aggressive Vertebral Hemangioma: The Mystery of Spastic Legs Unveiled by a Purple Shoulder. Cureus. 2022 Jan 24;14(1):e21568. doi: 10.7759/cureus.21568. PMID: 35228927; PMCID: PMC8873442.
Fiore G, Bertani GA, Tariciotti L, Borsa S, Paolucci A, Taramasso L, Locatelli M, Pluderi M. Vertebral Body Infarction after Transarterial Preoperative Embolization of a Vertebral Hemangioma. J Neurol Surg A Cent Eur Neurosurg. 2021 Dec 12. doi: 10.1055/s-0041-1739215. Epub ahead of print. PMID: 34897610.
Srinivasan G, Moses V, Padmanabhan A, Ahmed M, Keshava SN, Krishnan V, Joseph BV, Raju KP, Rajshekhar V. Utility of spinal angiography and arterial embolization in patients undergoing CT guided alcohol injection of aggressive vertebral hemangiomas. Neuroradiology. 2021 Nov;63(11):1935-1945. doi: 10.1007/s00234-021-02788-7. Epub 2021 Aug 24. PMID: 34427707.
Ridzoňová L, Fedičová M, Andráš T, Urdzík P, Gdovinová Z. Lower-limb progressive paraparesis management and diagnosis overview in a pregnant woman with vertebral haemangioma. Womens Health (Lond). 2022 Jan-Dec;18:17455057221099018. doi: 10.1177/17455057221099018. PMID: 35574823.
A significant proportion of patients with significant neurovascular compression fail to achieve long-term pain relief after technically successful surgery. Neuroimaging using magnetic resonance imaging (MRI) provides a non-invasive method to generate objective biomarkers of eventual response to TN surgery 1).
Younger patients with TN had worse long-term pain outcomes following MVD. Additional factors associated with postoperative recurrence included poor preoperative pain control (BNI score > IV) and multivessel compression. Furthermore, SCA combined with PV was confirmed to be associated with a worse outcome 2).
Not all patients with TN manifest unequivocal neurovascular compression (NVC). Furthermore, over time patients with an initially successful MVD manifest a relentless rate of TN recurrence.
It does not achieve 100 % cure rate. Re-exploration of the posterior fossa may carry increased risk over first-time MVD and is not always successful, so other treatments are needed.
Wang Z, Zhao Z, Song Z, Wang Y, Zhao Z. The application of magnetic resonance imaging (MRI) for the prediction of surgical outcomes in trigeminal neuralgia. Postgrad Med. 2022 May 3:1-7. doi: 10.1080/00325481.2022.2067612. Epub ahead of print. PMID: 35503235.
Shi J, Qian Y, Han W, Dong B, Mao Y, Cao J, Guan W, Zhou Q. Risk factors for outcomes following microvascular decompression for trigeminal neuralgia. World Neurosurg. 2020 Jan 17. pii: S1878-8750(20)30100-5. doi: 10.1016/j.wneu.2020.01.082. [Epub ahead of print] PubMed PMID: 31958591.
Mastronardi L, Caputi F, Rinaldi A, Cacciotti G, Roperto R, Scavo CG, Stati G, Sufianov A. Typical Trigeminal Neuralgia: Comparison of Results between Patients Older and Younger than 65 Operated on with Microvascular Decompression by Retrosigmoid Approach. J Neurol Surg A Cent Eur Neurosurg. 2019 Aug 29. doi: 10.1055/s-0039-1693126. [Epub ahead of print] PubMed PMID: 31466107.
Postoperative morbidity included common side effects such as facial numbness in 66 (97.1 %) patients, masseter muscle weakness in 19 (27.9 %) patients, paresthesia in 7 (10.3 %) patients, and diplopia secondary to abducens nerve weakness in 1 (1.5 %) patient 2)
The main reason for ineffective or short-term recurrence of PBC in trigeminal neuralgia patients is the ineffectively compressed of trigeminal ganglion.According to the different types of patients,the use of individualized modified surgical scheme can improve the efficacy of PBC surgery 3).
Extracranial complications
Bloody saliva Stensen duct puncture
Facial hematoma/A-V fistula Puncture of internal MA and pterygoid plexus
Injury to ICA, jugular vein Excessively medial displacement of the needle causing injury to the ICA in the FL,
posterolateral displacement causing injury to the jugular vein
Injury to Eustachian tube Posterior displacement of the needle
Blindness Needle inserted anteriorly and medially passing through inferior orbital fissure to the orbital apex
Intracranial complications
Carotid-cavernous fistula ICA injury in the CS
Temporal lobe hematoma Dura mater penetration and intradural balloon inflation
Brainstem lesion Guiding stylet/balloon catheter far from the petrous ridge
Diplopia Compression of CN VI (most common) or CN IV
Meningitis Oral mucosa puncture, contamination or improper sterility 4).
Lichtor and Mullan from one hundred patients treated by this method that have been followed for 1 to 10 years; treatment has been technically successful in 97% of cases. Relief persisted at five years in 80%, and it is estimated that at 10 years the figure will be 70%. There were no deaths, no cerebral damage, no keratitis, and no analgesia dolorosa; 4% of the patients reported dysesthesia 5).
Most of the minor surgical complications observed were also related to avoidable technical errors 6)
Wang CM, Guan ZY, Wang QC, Zhang J, Ma Y, Zhao P. The Effect of Depth of Anesthesia on Hemodynamic Changes Induced by Therapeutic Compression of the Trigeminal Ganglion. J Neurosurg Anesthesiol. 2019 May 27. doi: 10.1097/ANA.0000000000000612. [Epub ahead of print] PubMed PMID: 31145173.
Chong YL, Xu W, Wang J, Jiang CR, Liang WB. [The ineffective or short-term recurrence of trigeminal neuralgia after microballoon compression:different causes and management strategies]. Zhonghua Wai Ke Za Zhi. 2022 May 1;60(5):473-478. Chinese. doi: 10.3760/cma.j.cn112139-20210825-00391. Epub ahead of print. PMID: 35359090.
Radiofrequency ablation for Spinal osteoid osteoma
Complete excision With osteoid osteomas, only complete surgical excision ensures the least risk of local recurrence, and effectively provides immediate pain relief and early mobilization. Newer, minimally invasive methods, including. percutaneous CT-guided radiofrequency ablation (RFA), are gaining popularity internationally for the treatment of extra spinal tumors 1).
Complete surgical excision of the nidus is curative, providing symptomatic relief, and is the traditionally preferred treatment. However, surgery has disadvantages, including the difficulty of locating the lesion intraoperatively, the need for prolonged hospitalization, and the possibility of postoperative complications ranging from an unsatisfactory cosmetic result to a fracture. Percutaneous radiofrequency (RF) ablation, which involves the use of thermal coagulation to induce necrosis in the lesion, is a minimally invasive alternative to surgical treatment of osteoid osteoma. With reported success rates approaching 90%, RF ablation should be considered among the primary options available for treating this condition 2).
PubMed, Scopus, and CENTRALdatabases were searched in accordance with PRISMA guidelines. Studies with available data on safety and clinical outcomes following RFA for spinal OO were included.
In the 14 included studies (11 retrospective; 3 prospective), 354 patients underwent RFA for spinal OO. The mean ages ranged from 16.4 to 28 years (Females = 31.3%). Lesion diameters ranged between 3 and 20 mm and were frequently seen in the posterior elements in 211/331 (64%) patients. The mean distance between OO lesions and neural elements ranged between 1.7 and 7.4 mm. The estimated pain reduction on the numerical rating scale was 6.85/10 (95% confidence intervals [95%CI] 4.67-9.04) at a 12-24-month follow-up; and 7.29/10 (95% CI 6.67-7.91) at a >24-month follow-up (range 24-55 months). Protective measures (e.g., epidural air insufflation or neuroprotective sterile water infusion) were used in 43/354 (12.1%) patients. Local tumor progression was seen in 23/354 (6.5%) patients who were then successfully re-treated with RFA or open surgical resection. Grade I-II complications such as temporary limb paresthesia and wound dehiscence were reported in 4/354 (1.1%) patients. No Grade III-V complications were reported.
RFA demonstrated safety and clinical efficacy in most patients harboring painful spinal OO lesions. However, further prospective studies evaluating these outcomes are warranted 3).
Case series
Percutaneous Radiofrequency Ablation Using a Navigational Bipolar Electrode System 4).
Between 2002 and 2012, a total of 61 patients (46 male and 15 female, mean age 26.4 ± 12.7 years) were subjected to RFA for spinal OO. The diagnosis of OO was made after a period of pain and symptoms of 20.6 ± 14.4 months. RFA was performed under conscious sedation and local analgesia. Clinical symptoms were evaluated at 3, 6, and12 months, and at the end of the time of the present investigation. Mean follow-up was 41.5 ± 7.1 months.
Results: The primary efficacy of RFA, complete regression of symptoms, was obtained in 57 out of 61 patients (93.4%). Four out of 61 (6.5%) patients showed a relapse of OO (after 3 months); 2 out of 4 were subjected to a second RFA, the remaining ones were subjected to surgery. There was one complication (case of lower limb paresthesia for 30 days after the ablation) and one possible complication (a disc herniation).
Conclusion: CT-guided RFA is an excellent treatment for spinal OO. Our data suggest that this procedure should be considered for the first stage of therapy for this disease 5)
Between March 2009 and July 2016, 8 consecutive patients with spinal osteoid osteomas were enrolled in the study and underwent 9 CT-guided RFA procedures. All patients presented with spinal pain (median preoperative visual analog scale [VAS] score 7.55, range 6-8.8) predominantly during the night, and they all had normal neurological examination results before the procedure. Pain (according to the VAS score) and neurological status were reassessed immediately before discharge, with further follow-up at 1, 6, and 12 months after the procedure. At the final follow-up, VAS score, neurological examination, patient satisfaction, and a radiological control (CT scan) were documented (median 48 months, range 12-84 months). VAS scores before and after the procedure were compared during the 3 days before surgery (D0), on the day of the surgery, Day 1 (D1), and at the final follow-up. RESULTS No neurological deficit was documented following the procedure or at the final follow-up. A statistically significant reduction in the VAS score was observed on Day 1 (mean 2.56 ± 0.68, p = 0.005) compared with D0. At the final follow-up, all patients reported a VAS score of 0 and a satisfaction rate of 100%. Only 1 patient had recurrent symptoms (pain, VAS score 8.1) 6 months after the initial RFA. A second procedure was performed, and the patient was subsequently symptom free at the final follow-up. CT scanning performed in all patients (12-84 months post-RFA) showed residual sclerosis in 4 patients and complete resolution of the radiological lesion in the remaining 4 patients. CONCLUSIONS CT-guided RFA appears to be a safe and effective method for the management of spinal osteoid osteoma and can be safely performed for lesions close to the dura or exiting nerve root based on the motor response threshold testing performed during the procedure. It should be considered the treatment of choice for spinal osteoid osteomas refractory to conservative treatment, thus avoiding more aggressive spinal approaches with subsequent potential morbidity 6).
The records of all patients with osteoid osteomas of the spine managed with thermal ablation at two academic centers from 1993 to 2008 were reviewed.
Results: Seventeen patients (13 male patients, four female patients; mean age, 25.9 years) had lesions in the lumbar (seven patients), thoracic (six patients), cervical (three patients), and sacral (one patient) regions of the spine. Two lesions were in the vertebral body, one was within the dens, and the others were in the posterior elements. The mean lesion diameter was 8.8 mm, and the mean distance between the lesion and the closest neural element was 4.3 mm. The lesions were managed with laser (13 lesions) or radiofrequency (four lesions) ablation. Special thermal protection techniques involving the epidural injection of gas or cooled fluid were used. Pain levels were assessed immediately before the procedure and on the day after the procedure. Long-term follow-up findings were available for 11 patients. No complications were encountered, and all patients reported relief of pain. The 11 patients who participated in long-term follow-up reported continued relief of pain.
Conclusion: Percutaneous thermal ablation can be used to manage spinal osteoid osteomas close to the neural elements. Special thermal protection techniques may add a margin of safety 7).
A prospective study on 24 patients with spinal osteoid osteoma treated with radiofrequency ablation (RFA).
Objective: To determine if and when computed tomography (CT)-guided RFA is a safe and effective treatment for spinal osteoid osteomas.
Summary of background data: Surgery has been considered the standard treatment for spinal osteoid osteomas. Surgery may cause spinal instability, infection, and nervous injury. We evaluated CT-guided RFA as an alternative treatment.
Methods: A total of 28 RFA procedures in 24 patients with spinal osteoid osteoma were performed, using a 5-mm noncooled electrode. Clinical symptoms and spinal deformity were evaluated before and after the procedure. Unsuccessful treatment was defined as the presence of residual or recurrent symptoms. The mean follow-up was 72 months (range: 9-142 months).
Results: Nineteen (79%) patients were successfully treated after 1 RFA, and all except one after repeat RFA. One patient with nerve root compression needed further surgery. No complications were observed. Spinal deformity persisted in 3 of 7 patients after successful RFA.
Conclusion: CT-guided RFA is a safe and effective treatment for spinal osteoid osteoma. Surgery should be reserved for lesions causing nerve root compression 8).
Gasbarrini A, Cappuccio M, Bandiera S, Amendola L, van Urk P, Boriani S. Osteoid osteoma of the mobile spine: surgical outcomes in 81 patients. Spine (Phila Pa 1976). 2011 Nov 15;36(24):2089-93. doi: 10.1097/BRS.0b013e3181ffeb5e. PMID: 21304430.
Rybak LD, Gangi A, Buy X, La Rocca Vieira R, Wittig J. Thermal ablation of spinal osteoid osteomas close to neural elements: technical considerations. AJR Am J Roentgenol. 2010 Oct;195(4):W293-8. doi: 10.2214/AJR.10.4192. PMID: 20858792.
For this procedure, different potential operative and technical nuances exist.
Puncture of the foramen ovale by conventional single-plane fluoroscopy can be difficult in cases of local anatomic abnormalities.
Mendes et al. presented the case of a 49-year-old woman diagnosed with idiopathic trigeminal neuralgia refractory to pharmacological treatment. After failure of puncture by conventional fluoroscopy for percutaneous gasserian ganglion balloon compression due to a narrow foramen ovale, the patient was submitted to puncture guided by computed tomography.
Alternative imaging methods, such as computed tomography, should be considered when Percutaneous Foramen Ovale Puncture by conventional single-plane fluoroscopy fails, to minimize the risk of potential complications triggered by frustrated puncture attempts 1).
Between March 2018 and February 2021, 20 peroral balloon compression rhizotomy procedures with a 3D-PSGT were performed in 18 consecutive trigeminalpain patients (13 female, mean age 58 yr). We registered the procedure duration, side effects, complications, and trigeminal function. The therapeutic effect was gauged from reduction of TP and use of analgesics.
Results: All catheter insertions and rhizotomy procedures were successful at the first attempt. Apart from fluoroscopy, no auxiliary material was necessary. The average length of surgery was 19 min (range, 11-27 min). In total, 8 patients indicated complete analgesia and 6 patients pain relief; in 4 patients, persistence of TP was observed during follow-up examinations of up to 20 mo. In total, 6 patients reported of new mild to moderate facial hypesthesia affecting the trigeminal branches V2, V3, or V1-3. No masticatory musculature or corneal affections and device-related complications occurred.
The peroral 3D-PSGT trigeminal rhizotomy is straightforward for the neurosurgeon. This operative approach allows for rapid, safe, and simple foramen ovale puncture cannulation in TP patients and reduces the use of additional equipment, radiation exposure, and procedure time 2).
Cannulation procedures, including those utilizing neuronavigational technology, are occasionally complicated by anatomical variation of the FO, sometimes resulting in miscannulation and subsequent adverse events. The FO, while commonly thought of as oval-shaped, has also been described as “almond,” “banana,” “D shape,” “pear,” and “triangular.” 3).
Forty-five patients were included in the study. All patients underwent a computed tomography examination. Among them, the simulated preoperative puncture pathway was reconstructed on the basis of computed tomography scan examination for 22 patients. Procedures were performed by 2 surgeons: one experienced surgeon and another young surgeon with surgical qualification. The puncturing time and cumulative radiation exposure dose, from start of the puncturing until reaching the foramen ovale, were recorded. Postoperative pain relief, facial hypoesthesia, masticatory muscle weakness, and other complications were recorded.
Results: In all cases, the procedure of cannulation was completed successfully. The puncturing time for both the experienced and young surgeon with the use of preoperative image simulation seemed to be time-saving. The young surgeon had less cumulative radiation exposure with the use of preoperative image simulation. Moreover, the intraoperative puncture pathways were almost consistent with the preoperative simulated images. The rest of the process went smoothly. Short-term outcomes of all the 45 patients were satisfactory.
Based on our preliminary experience, the preoperative image simulation-guided technique is useful during these cases 5).
Guo et al., described a technique that includes a stereotactic approach in the preoperative plan in cases where the foramen ovale is difficult to access for radiofrequency thermocoagulation of the Gasserian ganglion.
The study included 395 patients for whom three-dimensional computed tomographic reconstruction of the skull base, maxilla, and mandible was conducted before surgery. Accessibility of the foramen ovale was defined using numerical data from the three-dimensional computed tomographic reconstruction images. In those patients for whom accessibility of the foramen ovale was considered difficult, the authors used a stereotactic frame to design an individual operative plan. Adjustments of a single point of data,-that is, a change in X axis, Y axis, or an arc angle-were guided by radiographic fluoroscopy images. After verifying successful cannulation and electroneurophysiology, thermocoagulation targets-especially multiple targets recorded as data on the Z axis of the stereotactic approach-were identified and treated.
There were 24 patients who met the predetermined criteria for having a difficult-to-access foramen ovales-that is, they had at least two contributing factors and/or involvement of division V1 . Twenty-one of the 24 patients required a single satisfactory puncture; three patients required two to three punctures to successfully access the foramen ovale. There were no permanent complications from the procedure.
The authors conclude that this stereotactic approach combined with three-dimensional computed tomographic reconstruction model can improve the accuracy, safety, and efficiency of percutaneous radiofrequency thermocoagulation in patients with trigeminal neuralgia for whom the foramen ovale is difficult to access 6).
Ding et al., assessed the feasibility of accessing the Gasserian ganglion through the FO from a mandibular angle under computed tomography (CT) and neuronavigation guidance.A total of 108 patients with TN were randomly divided into 2 groups (Group G and Group H) using a random number table. In Group H, anterior Hartel approach was used to puncture the FO; whereas in Group G, a percutaneous puncture through a mandibular angle was used to reach the FO. In both groups, procedures were guided by CT imaging and neuronavigation. The success rates, therapeutic effects, complications, and recurrence rates of the 2 groups were compared.The puncture success rates in Group H and Group G were 52/54 (96.30%) and 49/54 (90.74%), respectively (P = 0.24). The 2 procedural failures in Group H were rescued by using submandibular trajectory, and the 5 failures in Group G were successfully reapproached by Hartel method. Therapeutic effects as measured by Barrow Neurological Institute Pain Scale (P = 0.03) and quality of life (QOL) scores (P = 0.04) were significantly better in Group G than those in Group H at 36 months posttreatment. Hematoma developed in 1/54 (1.85%) cases in Group H, and no cases of hematoma were observed in Group G (P = 0.33). In Group H, RFT resulted in injury to the unintended trigeminal nerve branches and motor fibers in 27/52 (51.92%) cases; in Group G, it resulted in the same type of injury in 7/49 cases (14.29%) (P < 0.01). In Group H, the 24- and 36-month recurrence rates were 12/51 (23.53%) and 20/51 (39.22%), respectively; in Group G, these recurrence rates were 7/49 (12.24%) and 9/49 (16.33%, P = 0.03), respectively.CT- and neuronavigation-guided puncture from a mandibular angle through the FO into the Gasserian ganglion can be safely and effectively used to deliver RFT for the treatment of pTN. This method may represent a viable option to treat TN in addition to Hartel approach 7).
The goals of a study of Peris-Celda et al., were to demonstrate the anatomical basis of complications related to FO puncture, and provide anatomical landmarks for improvement of safety, selective lesioning of the trigeminal nerve (TN), and optimal placement of electrodes.
Both sides of 50 dry skulls were studied to obtain the distances from the FO to relevant cranial base references. A total of 36 sides from 18 formalin-fixed specimens were dissected for Meckel cave and TN measurements. The best radiographic projection for FO visualization was assessed in 40 skulls, and the optimal trajectory angles, insertion depths, and topographies of the lesions were evaluated in 17 specimens. In addition, the differences in postoperative pain relief after the radiofrequency procedure among different branches of the TN were statistically assessed in 49 patients to determine if there was any TN branch less efficiently targeted.
Most severe complications during FO puncture are related to incorrect needle placement intracranially or extracranially. The needle should be inserted 25 mm lateral to the oral commissure, forming an approximately 45° angle with the hard palate in the lateral radiographic view, directed 20° medially in the anteroposterior view. Once the needle reaches the FO, it can be advanced by 20 mm, on average, up to the petrous ridge. If the needle/radiofrequency electrode tip remains more than 18 mm away from the midline, injury to the cavernous carotid artery is minimized. Anatomically there is less potential for complications when the needle/radiofrequency electrode is advanced no more than 2 mm away from the clival line in the lateral view, when the needle pierces the medial part of the FO toward the medial part of the trigeminal impression in the petrous ridge, and no more than 4 mm in the lateral part. The 40°/45° inferior transfacial-20° oblique radiographic projection visualized 96.2% of the FOs in dry skulls, and the remainder were not visualized in any other projection of the radiograph. Patients with V1 involvement experienced postoperative pain more frequently than did patients with V2 or V3 involvement. Anatomical targeting of V1 in specimens was more efficiently achieved by inserting the needle in the medial third of the FO; for V2 targeting, in the middle of the FO; and for V3 targeting, in the lateral third of the FO.
Knowledge of the extracranial and intracranial anatomical relationships of the FO is essential to understanding and avoiding complications during FO puncture. These data suggest that better radiographic visualization of the FO can improve lesioning accuracy depending on the part of the FO to be punctured. The angles and safety distances obtained may help the neurosurgeon minimize complications during FO puncture and TN lesioning 8).
Koizuka et al., presented a new method for percutaneous radio-frequency thermocoagulation of the Gasserian ganglion, in which computed tomography (CT) fluoroscopy is used to guide needle placement.
In the present study, 15 patients with trigeminal neuralgia underwent percutaneous radio-frequency thermocoagulation of the Gasserian ganglion guided by high-speed real-time CT fluoroscopy.
RESULTS: Trigeminal neuralgia was improved in all patients after treatment without any severe complications. Moderate dysesthesia occurred in only one case.
CT fluoroscopy-guided percutaneous radio-frequency thermocoagulation of the Gasserian ganglion was safe, quick, and effective for patients with intractable idiopathic trigeminal neuralgia 9).
Mendes PD, Martins da Cunha PH, Monteiro KKO, Quites LV, Fonseca Filho GA. Percutaneous Foramen Ovale Puncture: Usefulness of Intraoperative CT Control, in the Eventuality of a Narrow Foramen [published online ahead of print, 2020 Sep 16]. Stereotact Funct Neurosurg. 2020;1-4. doi:10.1159/000509821
Zdilla MJ, Fijalkowski KM. The Shape of the Foramen Ovale: A Visualization Aid for Cannulation Procedures. J Craniofac Surg. 2016 Dec 23. doi: 10.1097/SCS.0000000000003325. [Epub ahead of print] PubMed PMID: 28027173.
Kaplan M, Erol FS, Ozveren MF, Topsakal C, Sam B, Tekdemir I. Review of complications due to foramen ovale puncture. J Clin Neurosci. 2007 Jun;14(6):563-8. Epub 2006 Dec 13. PubMed PMID: 17169562.
Guo W, Shi H, Wen X, Qian T. A Simple Method for Foramen Ovale Puncture Based on Preoperative Image Simulation in Percutaneous Microcompression of the Trigeminal Ganglion. Oper Neurosurg (Hagerstown). 2022 Mar 3. doi: 10.1227/ONS.0000000000000123. Epub ahead of print. PMID: 35240674.
Guo Z, Wu B, Du C, Cheng M, Tian Y. Stereotactic Approach Combined with 3D CT Reconstruction for Difficult-to-Access Foramen Ovale on Radiofrequency Thermocoagulation of the Gasserian Ganglion for Trigeminal Neuralgia. Pain Med. 2016 Sep;17(9):1704-16. doi: 10.1093/pm/pnv108. Epub 2016 Feb 13. PubMed PMID: 26874883.
Ding W, Chen S, Wang R, Cai J, Cheng Y, Yu L, Li Q, Deng F, Zhu S, Yu W. Percutaneous radiofrequency thermocoagulation for trigeminal neuralgia using neuronavigation-guided puncture from a mandibular angle. Medicine (Baltimore). 2016 Oct;95(40):e4940. PubMed PMID: 27749549; PubMed Central PMCID: PMC5059051.
Lesions in the cavernous sinus involve cranial nerves III, IV, VI, and V1 & V2 (ophthalmic and maxillary divisions of the trigeminal nerve), and spare II and V3.
In Sturge-Weber syndrome: Ipsilateral port-wine facial nevus (nevus flammeus) usually in the distribution of 1st division of trigeminal nerve (forehead and/or eyelid) (rarely bilateral): not always present, alternatively sometimes in V2 or V3 regions 1).
Postoperative trigeminal nerve symptoms occur transiently in 22% and permanently in 11% following microsurgery, similar to the results of SRS 2).
Microvascular decompression for trigeminal neuralgia
Microvascular decompression is a first-line neurosurgical approach for classical trigeminal neuralgia with neurovascular conflict, but can show clinical relapse despite proper decompression. Second-line destructive techniques like radiofrequency thermocoagulation have become reluctantly used due to their potential for irreversible side effects. Subcutaneous peripheral nerve field stimulation (sPNFS) is a minimally invasive neuromodulatory technique which has been shown to be effective for chronic localised pain conditions.
Teflon™ and Ivalon® are two materials used in MVD for TN. It is an effective treatment with long-term symptom relief and recurrence rates of 1-5% each year. Ivalon® has been used less than Teflon™ though is associated with similar success rates and similar complication rates 2)
Although microvascular decompression (MVD) is the most effective long-term operative treatment for TN, its use in older patient populations has been debated due to its invasive nature. The symptoms and surgical findings presented in a cohort for young-onset TN are similar to those reported in elderly adults. MVD appears to be a safe and effective treatment for young patients with TN 3).
Compared with the standard microscope-assisted techniques, the 3D exoscopic endoscope-assisted MVD offers an improved visualisation without compromising the field of view within and outside the surgical field 4).
Fully endoscopic microvascular decompression for trigeminal neuralgia via keyhole approach
97 patients with primary trigeminal neuralgia (PTN) underwent fully endoscopic microvascular decompression (MVD) via keyhole approach in Capital Medical University Affiliated Beijing Shijitan Hospital from December 2014 to February 2019 was collected. During fully endoscopic MVD in PTN via keyhole approach, performer use natural clearance without grinding except developed rock bone crest or excessive retraction of the brain tissue, visually and panoramically observe and evaluate the CPA area, accurately identify the responsible vessels, to avoid the omission of responsible vessels or insufficient decompression. And the use of preplaced technology, bridging technology and submersible technology, ensure the efficacy of surgery and reduce the surgical side injuries. Barrow Neurological Institute Pain Intensity Score was used to evaluate the efficacy and identify the recurrence. The surgical efficacy was analyzed. The offending vessels were identified under endoscope in 96 cases. Among them, arterial compression was found in 77 cases, venous compression in 6 cases, and both arterial and venous compression in 13 cases. About the pain outcomes, 87 cases had immediate and complete relief of pain, 5 cases had almost relief of pain, 4 cases had partial relief of pain, and still needed medication control, but the dose was lower than that before operation, and 1 case had no obvious relief of pain. About complications, there were 4 cases of temporary facial numbness, 1 case of temporary hearing loss, both of them recovered after symptomatic treatment. There was no cerebral infarction or hemorrhage, intracranial or incision infection. All cases were followed up for 3.0-38.0 months with a median period of(22.4±2.2) months. During the follow-up periods, postoperative recurrence occurred in 3 cases. Fully endoscopic MVD for PTN through keyhole approach, provides panoramic view to avoid omission of offending vessels and reduce complications, seemed to be a safe and effective surgical method 5).
Systematic Review and Meta-Analysis
Using preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, PubMed, Cochrane Library, and Scopus were queried for primary studies examining pain outcomes after MVD for TN published between 1988 and March 2018. Potential biases were assessed for included studies. Pain freedom (ie, Barrow Neurological Institute score of 1) at last follow-up was the primary outcome measure. Variables associated with pain freedom on preliminary analysis underwent formal meta-analysis. Odds ratios (OR) and 95% confidence intervals (CI) were calculated for possible predictors.
Outcome data were analyzed for 3897 patients from 46 studies (7 prospective, 39 retrospective). Overall, 76.0% of patients achieved pain freedom after MVD with a mean follow-up of 1.7 ± 1.3 (standard deviation) yr. Predictors of pain freedom on meta-analysis using random effects models included (1) disease duration ≤5 yr (OR = 2.06, 95% CI = 1.08-3.95); (2) arterial compression over venous or other (OR = 3.35, 95% CI = 1.91-5.88); (3) superior cerebellar artery involvement (OR = 2.02, 95% CI = 1.02-4.03), and (4) type 1 Burchiel classification (OR = 2.49, 95% CI = 1.32-4.67).
Approximately three-quarters of patients with drug-resistant TN achieve pain freedom after MVD. Shorter disease duration, arterial compression, and type 1 Burchiel classification may predict a more favorable outcome. These results may improve patient selection and provider expectations 6).
Sivakanthan S, Van Gompel JJ, Alikhani P, van Loveren H, Chen R, Agazzi S. Surgical management of trigeminal neuralgia: use and cost-effectiveness from an analysis of the medicare claims database. Neurosurgery. 2014 Sep;75(3):220-6. doi: 10.1227/NEU.0000000000000430. PubMed PMID: 24871139.
Pressman E, Jha RT, Zavadskiy G, Kumar JI, van Loveren H, van Gompel JJ, Agazzi S. Teflon™ or Ivalon®: a scoping review of implants used in microvascular decompression for trigeminal neuralgia. Neurosurg Rev. 2019 Nov 30. doi: 10.1007/s10143-019-01187-0. [Epub ahead of print] Review. PubMed PMID: 31786660.
Yu F, Yin J. Young-onset trigeminal neuralgia: a clinical study and literature review. Acta Neurochir (Wien). 2021 Apr 17. doi: 10.1007/s00701-021-04848-6. Epub ahead of print. PMID: 33864143.
Li Ching Ng A, Di Ieva A. How I do it: 3D exoscopic endoscope-assisted microvascular decompression. Acta Neurochir (Wien). 2019 May 29. doi: 10.1007/s00701-019-03954-w. [Epub ahead of print] PubMed PMID: 31144166.
Dental pain may have another origin than teeth. It may be caused by myofascial, neurovascular, cardiac, neurological, sinusal or psychological factors.
Trigeminal neuralgia
A high percentage of patients that are surgically treated for trigeminal neuralgia consult their dentist first and receive possibly unjustified dental treatment. Differential diagnoses include odontogenic pain syndromes as well as atypical orofacial pain. The present literature acknowledges difficulties in correctly diagnosing trigeminal neuralgia, but seems to underestimate the extent 1).
Treatment
It is notoriously difficult to treat. To date, there are no deep brain stimulation (DBS) studies on this specific pain condition and no optimal target or “sweet spot” has ever been defined.
To determine the optimal thalamic target for improving this condition by utilizing the steering abilities of a directional DBS electrode (Vercise CartesiaTM Model DB-2202-45, Boston Scientific).
A literature search and review of the database identified 3 potential thalamic targets. A directional lead was implanted in a patient with NDP and its current steering used to test the effects in each nucleus. The patient reported her pain after 2 wk of stimulation in a prospective randomized blindedclinical trial of one. Quality of life measurements were performed before and after 3 mo on their best setting.
They identified 3 potential nuclei: the Centromedian nucleus (CM), Ventral posteromedial nucleus (VPM), and Anterior pulvinar nucleus. The best results were during VPM stimulation (>90% reduction in pain) and CM stimulation (50% reduction). Following 3 mo of VPM-DBS in combination of lateral CM stimulation, their pain disability index dropped (from 25 to 0) and short form 36 improved (from 67.5 to 90).
VPM stimulation in combination with CM stimulation is a promising target for NDP. DBS electrode directionality can be used to test multiple targets and select a patient specific “sweet spot” for NDP treatment 2).
Case reports
Imholz et al. discuss 2 rare cases of patients who presented with a cerebellopontine angle tumor, who initially manifested with symptoms of dental pain.
The first patient, male, 44 years of age presented to his dentist with toothache (47), which led to its extraction. Five months later, a second painful episode, more characteristic, revealed the presence of a vestibular schwannoma, which was successfully treated and led to the disappearance of the pain. The second case, a 43-year-old female presented to her dentist with toothache (46), which lead the dentist perform a root filling. Two years later, with a 3rd episode of dental pain, more relevant of a trigeminal nevralgia, a epidermoid cyst of the right cerebellopontine angle was identified and successfully treated leading to the disappearance of the pain.
Cerebellopontine angle tumors of this type may lead, in exceptional cases to symptoms of dental pain. Therefore, in face of atypical tooth or facial pain, both a detailed medical history and a detailed examination are necessary, in order to investigate any neurological signs and symptoms, before undertaking any non-essential dental treatment, which may be detrimental for the patients 3).
von Eckardstein KL, Keil M, Rohde V. Unnecessary dental procedures as a consequence of trigeminal neuralgia. Neurosurg Rev. 2015 Apr;38(2):355-60; discussion 360. doi: 10.1007/s10143-014-0591-1. Epub 2014 Nov 25. PubMed PMID: 25418511.
Imholz B, Lombardi T, Scolozzi P. [Toothache: At what point has a pontocerebellar angle tumor to be evoked?]. Rev Stomatol Chir Maxillofac Chir Orale. 2015 May 19. pii: S2213-6533(15)00068-3. doi: 10.1016/j.revsto.2015.04.002. [Epub ahead of print] French. PubMed PMID: 26001346.
Possible pathways for facial pain include: trigeminal nerve (portio major as well as portio minor (motor root).
Supratentorial sensory perception, including facial pain, is subserved by the trigeminal nerve, in particular, by the branches of its ophthalmic nerve, which provide an extensive innervation of the dura mater and of the major brain blood vessels. In addition, contrary to previous assumptions, studies on awake patients during surgery have demonstrated that the mechanical stimulation of the pia mater and small cerebral vessels can also produce pain. The trigeminovascular system, located at the interface between the nervous and vascular systems, is therefore perfectly positioned to detect sensory inputs and influence blood flow regulation. Despite the fact that it remains only partially understood, the trigeminovascular system is most probably involved in several pathologies, including very frequent ones such as migraine, or other severe conditions, such as subarachnoid hemorrhage. The incomplete knowledge about the exact roles of the trigeminal system in headache, blood flow regulation, Blood-brain BarrierPermeability, and trigemino-cardiac reflex warrants for an increased investigation of the anatomy and physiology of the trigeminal system 1).
Anatomy
The trigeminal nerve complex is a very important and somewhat unique component of the nervous system. It is responsible for the sensory signals that arise from the most part of the face, mouth, nose, meninges, and facial muscles, and also for the motor commands carried to the masticatory muscles. These signals travel through a very complex set of structures: dermal receptors, trigeminal branches, Gasserian ganglion, central nuclei, and thalamus, finally reaching the cerebral cortex. Other neural structures participate, directly or indirectly, in the transmission and modulation of the signals, especially the nociceptive ones; these include vagus nerve, sphenopalatine ganglion, occipital nerves, cervical spinal cord, periaqueductal gray matter, hypothalamus, and motor cortex. But not all stimuli transmitted through the trigeminal system are perceivable. There is a constant selection and modulation of the signals, with either suppression or potentiation of the impulses. As a result, either normal sensory perceptions are elicited or erratic painful sensations are created 2).
Originating in the posterior fossa of the brain stem, it follows a long and complex course towards its distribution territory, crossing several regions with a complex anatomy and establishing important relationships with several structures.
The nerve fibers originate in the brainstem and are part of several grey matter nuclei occupying all the brainstem and even the first spinal cervical segments.
Each of these sensitive and motor nuclei represents different processing centers, and there is a true systematization of the information this nervous tract is responsible for conducting.
The sensitive nucleus is the largest, comprising 3 true sub-nuclei, each responsible for each aspect of the general sensitivity. The highest is the mesencephalic nucleus, located in the tegmentum close to the midline and to the grey matter close to the Sylvian aqueduct. The neurons that form this nucleus are in charge of the propioceptive integration in the Vth nerve territory, high level information for correct mastication. The main nucleus is in the pons, it is also situated in the depth of the tegmentum, and is responsible for the tactile integration of the territory of this nerve. Finally, the inferior nucleus occupies the tegmentum of the medulla, extending caudally to the first segments of the cervical spine, and is in charge of thermal and pain information. Its location explains the possible appearance of symptoms in the facial territory in patients with a degenerative/inflammatory disorder of the upper cervical spine. There is one single motor nucleus, located in the pons tegmentum supplying mastication muscles, and is correspondingly called mastication nucleus. The fibers related with all these nuclei gather in the pons and emerge through the lateral sector of its anterior aspect, forming a thick nervous tract with two roots: a thicker and lateral sensitive root and a thinner more medial motor root.
The only intra-axial segment of the Vth ends there and initiates its long course to its distribution territory; it is formed by different sub-segments before dividing itself into its terminal branches (the cisternal and Gasserian or transdural segments).
The point where the roots emerge in the brainstem is called “REZ” (Root Entry Zone), an anatomical landmark of great functional hierarchy.
The trigeminal nerve as the name indicates is composed of three large branches. They are the ophthalmic nerve (V1, sensory), maxillary nerve (V2, sensory), and mandibular nerve (V3, motor and sensory) branches. The large sensory root and smaller motor root leave the brainstem at the mid-lateral surface of pons.
Function
The trigeminal nerve (the fifth cranial nerve, or simply CN V) is a nerve responsible for sensation in the face and certain motor functions such as biting and chewing. It is the largest of the cranial nerves. Its name (“trigeminal” = tri- or three, and -geminus or twin, or thrice twinned) derives from the fact that each trigeminal nerve, one on each side of the pons, has three major branches: the ophthalmic nerve (V1), the maxillary nerve (V2), and the mandibular nerve (V3). The ophthalmic and maxillary nerves are purely sensory. The mandibular nerve has both cutaneous and motor functions.
Sensory information from the face and body is processed by parallel pathways in the central nervous system. The motor division of the trigeminal nerve is derived from the basal plate of the embryonic pons, while the sensory division originates from the cranial neural crest.
Terrier LM, Hadjikhani N, Velut S, Magnain C, Amelot A, Bernard F, Zöllei L, Destrieux C. The trigeminal system: The meningovascular complex- A review. J Anat. 2021 Feb 18. doi: 10.1111/joa.13413. Epub ahead of print. PMID: 33604906.
Goellner E, Rocha CE. Anatomy of Trigeminal Neuromodulation Targets: From Periphery to the Brain. Prog Neurol Surg. 2020 Oct 6;35:1-17. doi: 10.1159/000511257. Epub ahead of print. PMID: 33022684.
