fluid

Cerebrospinal fluid fistula

Cerebrospinal fluid fistula

A cerebrospinal fluid leak (CSFL) is a medical condition when the cerebrospinal fluid of a person leaks out of the dura mater.

There is a incomplete sealing of the dura mater and is a major complication of intradural procedures.

Classification

Cerebrospinal fluid fistula classification

Etiology

Cerebrospinal Fluid Fistula Etiology.

Diagnosis

see Cerebrospinal fluid fistula diagnosis.

Complications

Cerebrospinal fluid fistula complications

Prevention

Dural closure‘s reinforcement using different new dural sealants plays an important role in prevention. Moreover, the use of neuronavigation systems in skull base and posterior fossa surgery can help to minimize the size of approach and reduce the incidence of CSF leak. New minimally invasive spinal approaches, such as minimally invasive decompression for spinal degenerative disorders or performing selective laminotomy over laminectomy for intradural spinal pathology are very useful techniques to prevent CSF leak in this kind of surgery. In conclusion, although CSF leak remains a risky complication in neurosurgery, its prevention and treatment significantly benefited from advances in biomaterials and surgical technique 1).

Treatment

see Cerebrospinal fluid fistula treatment.

Bibliometrics

Ramos-Rincon et al. aimed to analyze research activity on cerebrospinal fluid (CSF) leaks in general and CSF cerebrospinal fluid rhinorrhea and cerebrospinal fluid otorrhea in particular and to identify the main topic clusters in these areas.

They identified all relevant documents, using the medical subject headings (MeSH) term “Cerebrospinal Fluid Leak”, that are indexed in the MEDLINE database between 1945 and 2018. They performed a descriptive bibliometric analysis and analyses of networks and research clusters in order to identify the main topic areas of research.

From 1945 to 2018, a total of 4,130 records were published with the term CSF leak, including 2,821 documents (68.1%) with the term CSF rhinorrhea and 1,040 documents (25.8%) with CSF otorrhea. The number of documents published increased from 10 in 1945-49 to 642 in 2010-14. Articles represented the dominant document type (86.8% of the documents analyzed), while case reports were the main type of study (37.4%). In terms of geographical distribution, researchers from the USA led in the number of signatures (39.1%), followed by those from the UK (7.5%). The most active areas of research in the field were “Postoperative Complications,” “Tomography, X-Ray Computed,” and “Magnetic Resonance Imaging.” The terms “Adults,” “Young Adult,” and “Middle-Aged” were most common in CSF rhinorrhea research; and the terms “Infant,” “Child, Preschool,” “Child,” and “Adolescent” were more common in CSF otorrhea.

Based on these findings, articles and case reports related to “Surgery” and “postoperative complications” associated with the cerebrospinal fluid fistula diagnosis are the main topics of study, highlighting the importance of this document type in advancing knowledge in the field 2).

1)

Rapisarda A, Orlando V, Izzo A, D’Ercole M, Polli FM, Visocchi M, Montano N. New Tools and Techniques to Prevent CSF Leak in Cranial and Spinal Surgery. Surg Technol Int. 2022 Apr 20;40:sti40/1577. Epub ahead of print. PMID: 35443285.
2)

Ramos-Rincon JM, Monjas-Canovas I, Abarca-Olivas J, Gras-Albert JR, Bellinchón-Romero I, Gonzalez-Alcaide G. Research in Cerebrospinal Fluid Leak (Rhinorrhea and Otorrhea): A Bibliometric Analysis From 1945 to 2018. Cureus. 2022 Feb 3;14(2):e21888. doi: 10.7759/cureus.21888. PMID: 35265419; PMCID: PMC8898118.

Cerebrospinal fluid shunt malfunction diagnosis

Cerebrospinal fluid shunt malfunction diagnosis

The diagnosis of cerebrospinal fluid shunt malfunction based on a careful clinical history, examination, and investigations such as computed tomography (CT) scanning and plain X-ray shunt series is not always straightforward 1).

For example, ventricular size may not change in cases with a blocked shunt. Pumping a shunt prechamber is notoriously unreliable and potentially dangerous 2).

Admission for observation is expensive and excessive CT scanning carries a radiation burden. Many patients may be admitted and subjected to CT scanning on multiple occasions. There is a need to develop more reliable methods of assessing shunt function and monitoring intracranial pressure (ICP) 3) 4) 5) 6) 7) 8).

Optic nerve sheath diameter may be assessed using ultrasound or magnetic resonance imaging (MRI). Implantable ICP sensors within a shunt system have been blighted by poor long-term stability. Long-term studies of the recently introduced Raumedic NEUROVENT-P-tel and the Miethke SENSOR RESERVOIR are awaited with a keen interest 9).

Several attempts have been made to measure the cerebrospinal fluid flow velocity utilizing different Phase contrast magnetic resonance imaging techniques. In a study, König et al. evaluated 3T (Tesla) MRI scanners for their effectiveness in determining of flow in the parenchymal portion of ventricular shunt systems with adjustable valves containing magnets.

At first, an MRI phantom was used to measure the phase-contrasts at different constant low flow rates. The next step was to measure the CSF flow in patients treated with ventricular shunts without suspected malfunction of the shunt under observation.

The measurements of the phantom showed a linear correlation between the CSF flow and corresponding phase values. Despite many artifacts resulting from the magnetic valves, the ventricular catheter within the parenchymal portion of shunt was not superimposed by artifacts at each PC MRI plane and clearly distinguishable in 9 of 12 patients. Three patients suffering from obstructive hydrocephalus showed a clear flow signal.

Cerebrospinal fluid flow detected within the parenchymal portion of the shunt by phase contrast magnetic resonance imaging may reliably provide information about the functional status of a ventricular shunt. Even in patients whose hydrocephalus was treated with magnetic adjustable valves, the CSF flow was detectable using PC MRI sequences at 3 T field strength 10).

Non-invasive techniques to assess ‘semi-quantitatively’ whether intracranial pressure is raised or not include optic nerve sheath diameter (ultrasound or MRI), tympanic membrane displacement and transcranial Doppler but none have yet been shown to be sufficiently accurate for routine clinical use in patients with potential shunt malfunction. Provision of a separate subcutaneous CSF reservoir is of proven benefit in allowing access to the cerebral ventricles to measure ICP and allow removal of CSF in an emergency

Various invasive diagnostic test procedures for the verification of shunt function have been described:

Invasive CSF pressure and flow measurements

CSF tap test and drip interval test

Infusion tests

Radioactive shuntogram.

By comparison, publications addressing the noninvasive pumping test are rare.

Noninvasive pumping test of all formerly published results are values derived from tests with a variety of reservoirs and valves (at least 2 types).

In a few reports, the shunt/reservoir type used is not even specified, although the technical parameters of such reservoirs and valves are obviously essential.

To judge occlusions distally from the reservoir other authors have had to close the pVC transcutaneously by manual compression.

This is never possible with a sufficient certainty and, if ever undertaken, it usually does provide a source of error.

Rapid cranial MRI was not inferior to CT for diagnosing ventricular shunt malfunction and offers the advantage of sparing a child ionizing radiation exposure 11).

References

1)

Spirig JM, Frank MN, Regli L, Stieglitz LH (2017) Shunt agerelated complications in adult patients with suspected shunt dysfunction . A recommended diagnostic workup. 1421–1428
2)

Bromby A, Czosnyka Z, Allin D, Richards HK, Pickard JD, Czosnyka M (2007) Laboratory study on “intracranial hypotension” created by pumping the chamber of a hydrocephalus shunt. Cerebrospinal Fluid Res 9:1–9
3)

Dupepe EB, Hopson B, Johnston JM, Rozzelle CJ, Oakes WJ, Blount JP, Rocque BG (2016) Rate of shunt revision as a function of age in patients with shunted hydrocephalus due to myelomeningocele. Neurosurg Focus 41(November):1–6
4)

Korinek AM, Fulla-Oller L, Boch AL, Golmard JL, Hadiji B, Puybasset L (2011) Morbidity of ventricular cerebrospinal fluid shunt surgery in adults: an 8-year study. Neurosurgery 68(4):985–994
5)

Paulsen AH, Lundar T, Lindegaard KF (2015) Pediatric hydrocephalus: 40-year outcomes in 128 hydrocephalic patients treated with shunts during childhood. Assessment of surgical outcome, work participation, and health-related quality of life. J NeurosurgeryPediatrics 16(6):633–641
6)

Richards H, Seeley H, Pickard J (2009) Who should perform shunt surgery? Data from the UK Shunt Registry. Cerebrospinal Fluid Res 6:S31
7)

Spiegelman L, Asija R, Da Silva SL, Krieger MD, McComb JG (2014) What is the risk of infecting a cerebrospinal fluid–diverting shunt with percutaneous tapping? J Neurosurg Pediatr 14(4):336– 339
8)

Tamber MS, Klimo P, Mazzola CA, Flannery AM (2014) Pediatric hydrocephalus: systematic literature review and evidence-based guidelines. Part 8: management of cerebrospinal fluid shunt infection. J Neurosurg Pediatr 14(Suppl1):60–71
9)

Antes S, Stadie A, Müller S, Linsler S, Breuskin D, Oertel J (2018) Intracranial Pressure–Guided Shunt Valve Adjustments with the Miethke Sensor Reservoir. World Neurosur 642–650
10)

König RE, Stucht D, Baecke S, Rashidi A, Speck O, Sandalcioglu IE, Luchtmann M. Phase-Contrast MRI Detection of Ventricular Shunt CSF Flow: Proof of Principle. J Neuroimaging. 2020 Nov 4. doi: 10.1111/jon.12794. Epub ahead of print. PMID: 33146931.
11)

Boyle TP, Paldino MJ, Kimia AA, Fitz BM, Madsen JR, Monuteaux MC, Nigrovic LE. Comparison of rapid cranial MRI to CT for ventricular shunt malfunction. Pediatrics. 2014 Jul;134(1):e47-54. doi: 10.1542/peds.2013-3739. Epub 2014 Jun 2. PubMed PMID: 24918222.

Cerebrospinal fluid leak after endoscopic skull base surgery

Cerebrospinal fluid leak after endoscopic skull base surgery

Although rates of postoperative morbidity and mortality have become relatively low in patients undergoing transnasal transsphenoidal surgery (TSS) for pituitary adenoma, cerebrospinal fluid fistulas remain a major driver of postoperative morbidity. Persistent CSF fistulas harbor the potential for headache and meningitis.

Staartjes et al., trained and internally validated a robust deep neural network-based prediction model that identifies patients at high risk for intraoperative CSF. Machine learning algorithms may predict outcomes and adverse events that were previously nearly unpredictable, thus enabling safer and improved patient care and better patient counseling 1).

The objective of a study of Umamaheswaran et al., was to assess the incidence of CSF leak following pituitary surgery and the methods of effective skull base repair. This retrospective observational study conducted in a tertiary care hospital after obtaining due clearance from the Institutional ethics committee. The charts of patients who underwent endonasal pituitary surgery between 2013 and 2018 were studied and details noted. Patients undergoing revision surgery or with history of preoperative radiotherapy were excluded from the study. 52 patients were included in the study. Based on the type of CSF leak, the patients were grouped into four. 19 patients (36.5%) had an intraoperative CSF leak. 3 patients developed a postoperative CSF leak. Based on the histopathology, 4 patients had ACTH secreting tumor. 8 patients had growth hormone secreting tumor, 22 had gonadotropin secreting tumor, 9 patients had a non-functioning tumour and 9 patients had prolactinoma. The type of skull base repair performed in these patients were grouped into 4.18 patients underwent type I repair, 21 patients underwent type II repair, 8 patients underwent type III repair and 5 patients underwent type IV repair. They observed that the pedicled nasoseptal flap is particularly advantageous over other repair techniques, especially in low pressure leaks. The strategy for skull base repair should be tailored to suit each patient to minimise the occurrence of morbidity and the duration of hospital stay 2).

Cerebrospinal fluid leakage is always the primary complication during the endoscopic endonasal skull base surgery.

Dural suturing technique may supply a rescue method. However, suturing and knotting in such a deep and narrow space are difficult. Training in the model can improve skills and setting a stepwise curriculum can increase trainers’ interest and confidence.

Xie et al. constructed an easy model using silicone and acrylic as sphenoid sinus and using the egg-shell membrane as skull base dura. The training is divided into three steps: Step 1: extracorporeal knot-tying suture on the silicone of sphenoid sinus, Step 2: intra-nasal knot-tying suture on the same silicone, and Step 3: intra-nasal egg-shell membrane knot-tying suture. Fifteen experienced microneurosurgical neurosurgeons (Group A) and ten inexperienced PGY residents (Group B) were recruited to perform the tasks. Performance measures were time, suturing and knotting errors, and needle and thread manipulations. The third step was assessed through the injection of full water into the other side of the egg to verify the watertight suture. The results were compared between two groups.

Group A finishes the first and second tasks in significantly less time (total time, 125.1 ± 10.8 vs 195.8 ± 15.9 min) and fewer error points (2.4 ± 1.3 vs 5.3 ± 1.0) than group B. There are five trainers in group A who passed the third step, this number in group B was only one.

This low cost and stepwise training model improved the suture and knot skills for skull base repair during endoscopic endonasal surgery. Experienced microneurosurgical neurosurgeons perform this technique more competent 3).

In-Hospital Costs

All endoscopic transsphenoidal approach for pituitary surgeries performed from January 1, 2015, to October 24, 2017, with complete data were evaluated in a retrospective single-institution study. The electronic medical record was reviewed for patient factors, tumor characteristics, and cost variables during each hospital stay. Multivariate linear regression was performed using Stata software.

The analysis included 190 patients and average length of stay was 4.71 days. Average total in-hospital cost was $28,624 (95% confidence interval $25,094-$32,155) with average total direct cost of $19,444 ($17,136-$21,752) and total indirect cost of $9181 ($7592-$10,409). On multivariate regression, post-operative cerebrospinal fluid (CSF) leak was associated with a significant increase in all cost variables, including a total cost increase of $40,981 ($15,474-$66,489, P = .002). Current smoking status was associated with an increased total cost of $20,189 ($6,638-$33,740, P = .004). Self-reported Caucasian ethnicity was associated with a significant decrease in total cost of $6646 (-$12,760 to -$532, P = .033). Post-operative DI was associated with increased costs across all variables that were not statistically significant.

Post-operative CSF leak, current smoking status, and non-Caucasian ethnicity were associated with significantly increased costs. Understanding of cost drivers of endoscopic transphenoidal pituitary surgery is critical for future cost control and value creation initiatives 4).

Case series

see Cerebrospinal fluid leak after endoscopic skull base surgery case series.

References

1)

Staartjes VE, Zattra CM, Akeret K, Maldaner N, Muscas G, Bas van Niftrik CH, Fierstra J, Regli L, Serra C. Neural network-based identification of patients at high risk for intraoperative cerebrospinal fluid leaks in endoscopic pituitary surgery. J Neurosurg. 2019 Jun 21:1-7. doi: 10.3171/2019.4.JNS19477. [Epub ahead of print] PubMed PMID: 31226693.
2)

Umamaheswaran P, Krishnaswamy V, Krishnamurthy G, Mohanty S. Outcomes of Surgical Repair of Skull Base Defects Following Endonasal Pituitary Surgery: A Retrospective Observational Study. Indian J Otolaryngol Head Neck Surg. 2019 Mar;71(1):66-70. doi: 10.1007/s12070-018-1511-4. Epub 2018 Oct 15. PubMed PMID: 30906716; PubMed Central PMCID: PMC6401034.
3)

Xie T, Zhang X, Gu Y, Sun C, Liu T. A low cost and stepwise training model for skull base repair using a suturing and knotting technique during endoscopic endonasal surgery. Eur Arch Otorhinolaryngol. 2018 Jun 1. doi: 10.1007/s00405-018-5024-2. [Epub ahead of print] PubMed PMID: 29858924.
4)

Parasher AK, Lerner DK, Glicksman JT, et al. Drivers of In-Hospital Costs Following Endoscopic Transphenoidal Pituitary Surgery [published online ahead of print, 2020 Aug 24]. Laryngoscope. 2020;10.1002/lary.29041. doi:10.1002/lary.29041

Craniopharyngioma Cyst Fluid

Craniopharyngioma Cyst Fluid

The dense oily fluid content of craniopharyngioma CPs is reported to cause brain tissue damage, demyelination and axonal loss in the hypothalamus; however, its exact effect on different cell types of CNS is still unexplored.

One cause of postoperative morbidity, and indeed mortality, is aseptic meningitis from spill-out of craniopharyngioma cyst contents.

Halliday and Cudlip from the John Radcliffe Hospital, developed a surgical technique for the management of large craniopharygngioma cysts extending into the third ventricle, to reduce this risk.

They described a technique of using an epidural catheter, inserted into the working channel of a neuroendoscope, to decompress the cystic portion of a craniopharyngioma cyst before opening the cyst wall widely, preventing spill-out of large volumes of cyst content into the ventricular system.

They had no cases of aseptic meningitis, nor any complications, from use of the described technique.

They believe that this is a safe and effective technique of decompression and fenestration of large suprasellar craniopharyngioma cysts that reduces rates of aseptic meningitis and the associated morbidity and mortality from this 1)

In a study, Ghosh et al. from Bangalore, collected CP cyst fluid (CCF) from mostly young patients during surgical removal and exposed it 9-10 days in vitro to the primary cultures derived from rat brain hypothalamus for 48 hours. A gradual decline in cell viability was noted with increasing concentration of CCF. Moreover, a distinct degenerative morphological transformation was observed in neurons and glial cells, including appearance of blebbing and overall reduction of the cell volume. Further, enhanced expression of Caspase-3 in neurons and glial cells exposed to CCF by immunofluorescence imaging, supported by Western blot experiment suggest CCF induced apoptosis of hypothalamic cells in culture.

They demonstrated the deleterious effects of the cyst fluid on various cell types within the tumors originating region of the brain and its surroundings for the first time. Taken together, this finding could be beneficial towards identifying the region specific toxic effects of the cyst fluid and its underlying mechanism 2).

Craniopharyngiomas (CPs) are cystic, encapsulated, slow-growing epithelial tumors. CPs can be aggressive forms invading and resorting surrounding structures of adjacent brain tissue, where Rosenthal fibers (RFs) are expressed. The aim of this study was to investigate the ultrastructure of these fibers in human biopsies and compare it with an experimental toxic model produced by the cortical infusion of the oil cyst fluid (“Oil machinery” fluid or OMF) from CPs to rats. For this purpose, the CPs from ten patients were examined by light and electron microscopy. OMF was administered to rats intracortically. Immunohistochemical detection of glial fibrillary acidic protein (GFAP) and vimentin was assessed. In both freshly obtained CPs and rat brain tissue, the presence of abundant cellular debris, lipid-laden macrophages, reactive gliosis, inflammation and extracellular matrix destruction were seen. Ultrastructural results suggest focal pathological disturbances and an altered microenvironment surrounding the tumor-brain junction, with an enhanced presence of RFs in human tumors. In contrast, in the rat brain different degrees of cellular disorganization with aberrant filament-filament interactions and protein aggregation were seen, although RFs were absent. Our immunohistochemical findings in CPs also revealed an enhanced expression of GFAP and vimentin in RFs at the peripheral, but not at the central (body) level. Through these findings we hypothesize that the continuous OMF release at the CPs boundary may cause tissue alterations, including damaging of the extracellular matrix, and possibly contributing to RFs formation, a condition that was not possible to reproduce in the experimental model. The presence of RFs at the CPs boundary might be considered as a major criterion for the degree of CPs invasiveness to normal tissue. The lack of RFs reactivity in the experimental model reveals that the invasive component of CPs is not present in the OMF, although the fluid per se can exert tissue damage 3).

Fifteen samples of cyst fluid and 14 samples of blood serum were collected from 14 patients with cystic forms of craniopharyngiomas and studied biochemically regarding total protein, albumin, immunoglobulins G and M contents, lactate and pH. Analysis of the data obtained for cyst fluids according to Felgenhauer and comparing them to those obtained for the corresponding blood sera led us to prove the hypothesis of blood-brain barrier impairment in patients with cyst formations in craniopharyngioma.

Arefyeva et al. have also revealed an elevated lactate content and decreased pH in cyst fluids compared with blood sera. Thus the pathogenesis of craniopharyngiomal cyst appears to be much more akin to those described for cysts accompanying other brain tumours than it was believed earlier 4).

A prospective study of cystic fluid in craniopharyngiomas in 10 patients was performed to correlate signal intensity on T1-weighted magnetic resonance (MR) images and biochemical analysis. Within 2 days before surgery, each patient underwent MR imaging before and after administration of gadopentetate dimeglumine. Five patients had cystic fluid lower in signal intensity than white matter, with protein levels less than 9,000 mg/dL (90.00 g/L) and no free methemoglobin. One of the five patients had the highest triglyceride concentration (84 mg/dL [0.95 mmol/L]) of all 10 patients; another of these five had the highest cholesterol concentration of all (270 mg/dL [6.98 mmol/L]). It is concluded that the increased signal intensity of cystic fluid in craniopharyngiomas on T1-weighted MR images can be caused by a protein concentration greater than or equal to 9,000 mg/dL (90.00 g/L), the presence of free methemoglobin, or both. In the ranges of concentrations measured in this study, cholesterol and triglyceride did not increase signal intensity 5).

References

1)

Halliday J, Cudlip S. A new technique of endoscopic decompression of suprasellar craniopharyngioma cyst. Acta Neurochir (Wien). 2019 Aug 4. doi: 10.1007/s00701-019-04024-x. [Epub ahead of print] PubMed PMID: 31377958.
2)

Ghosh M, Das S, Rao KVLN, Pruthi N, Ramesh VJ, Raju TR, Sathyaprabha TN. Effects of Craniopharyngioma Cyst Fluid on Neurons and Glial Cells cultured from rat brain hypothalamus. J Chem Neuroanat. 2018 Oct 16. pii: S0891-0618(18)30086-3. doi: 10.1016/j.jchemneu.2018.10.005. [Epub ahead of print] PubMed PMID: 30339791.
3)

Tena-Suck ML, Morales-Del Ángel AY, Hernández-Campos ME, Fernández-Valverde F, Ortíz-Plata A, Hernández AD, Santamaría A. Ultrastructural characterization of craniopharyngioma at the tumor boundary: A structural comparison with an experimental toxic model using “oil machinery” fluid, with emphasis on Rosenthal fibers. Acta Histochem. 2015 Oct;117(8):696-704. doi: 10.1016/j.acthis.2015.09.006. Epub 2015 Oct 26. PubMed PMID: 26515050.
4)

Arefyeva IA, Semenova JB, Zubairaev MS, Kondrasheva EA, Moshkin AV. Analysis of fluid in craniopharyngioma-related cysts in children: proteins, lactate and pH. Acta Neurochir (Wien). 2002 Jun;144(6):551-4; discussion 554. PubMed PMID: 12111487.
5)

Ahmadi J, Destian S, Apuzzo ML, Segall HD, Zee CS. Cystic fluid in craniopharyngiomas: MR imaging and quantitative analysis. Radiology. 1992 Mar;182(3):783-5. PubMed PMID: 1535894.

Update: Cerebrospinal fluid shunt complication

see Lumboperitoneal shunt complication.
see Ventriculoperitoneal shunt complication.
Ventricular shunts for pediatric hydrocephalus continue to be plagued with high failure rates. Reported risk factors for shunt failure are inconsistent and controversial. The raw or global shunt revision rate has been the foundation of several proposed quality metrics.
The most common problems related to cerebrospinal fluid shunt are shunt obstruction, shunt infection and shunt overdrainage. The incidence of shunt complications is higher when less time has elapsed since the previous shunt surgery. Nearly all shunt patients end up with one or multiple reoperations. Thorough history, head scan (ultrasound, CT or MRI) and plain x-ray (shunt series) are the corner stones when reviewing shunt problems.
Wong et al. performed a PubMed search using search terms “cerebral shunt,” “cerebrospinal fluid shunt,” “CSF shunt,” “ventriculoperitoneal shunt,” “cerebral shunt AND complications,” “cerebrospinal fluid shunt AND complications,” “CSF shunt AND complications,” and “ventriculoperitoneal shunt AND complications.” Only papers that specifically discussed the relevant complication rates were included. Papers were chosen to be included to maximize the range of rates of occurrence for the adverse events reported. RESULTS: In this review of the neurosurgery literature, the reported rate of mechanical malfunction ranged from 8% to 64%. The use of programmable valves has increased but remains of unproven benefit even in randomized trials. Infection was the second most common complication, with the rate ranging from 3% to 12% of shunt operations. A meta-analysis that included 17 randomized controlled trials of perioperative antibiotic prophylaxis demonstrated a decrease in shunt infection by half (OR 0.51, 95% CI 0.36-0.73). Similarly, use of detailed protocols including perioperative antibiotics, skin preparation, and limitation of OR personnel and operative time, among other steps, were shown in uncontrolled studies to decrease shunt infection by more than half. Other adverse events included intraabdominal complications, with a reported incidence of 1% to 24%, intracerebral hemorrhage, reported to occur in 4% of cases, and perioperative epilepsy, with a reported association with shunt procedures ranging from 20% to 32%. Potential management strategies are reported but are largely without formal evaluation.
Surgery for CSF shunt placement or revision is associated with a high complication risk due primarily to mechanical issues and infection. Concerted efforts aimed at large-scale monitoring of neurosurgical complications and consistent quality improvement within these highlighted realms may significantly improve patient outcomes 1).

Infection

see Cerebrospinal fluid infection.
see Shunt infection.

Shunt dysfunction

see Shunt dysfunction.

Shunt overdrainage

see Shunt overdrainage.
Solid noninfectious growing mass
Shunt-related craniocerebral disproportion.
Slit ventricle syndrome and secondary craniosynostosis are late-onset complications after shunt placement these 2 conditions occasionally occur together.
see Tension pneumocephalus after shunt insertion.
The results of shunt testing are helpful in many circumstances, such as the initial choice of shunt and the evaluation of the shunt when its dysfunction is suspected 2).
Shunting procedures for syringomyelia have been criticized due to the inconsistent long-term outcomes.
This is largely the result of small volume flow at a very low-pressure profile leading to occlusion or malfunction of the shunts.

 Noises
Patients have reported anecdotally on noises associated with their shunts 4).

Diagnosis

Radionuclide shuntogram is important in the evaluation of cerebrospinal fluid shunt complications such as mechanical failure, malpositioning, pseudocyst, or overdrainage. Bermo et al present a case of congenital hydrocephalus and posterior fossa cyst with multiple shunt procedures and revisions with breakage of the proximal tube of the ventriculoperitoneal shunt but preserved CSF drainage through the patent fibrous tract. Careful correlation with SPECT/CT images helped confirm the breakage and exclude CSF leak outside of the tract, which was suspected on planar images 3).

Books

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Case series

2017

Kaestner et al. from the Department of Neurosurgery, Klinikum Kassel, Germany, identified all patients who had been treated or followed in our neurosurgical department within a 15-year period from January 2000 up to the end of 2014. After approval of the local ethics committee all patients who were cognitively intact were explored by a questionnaire and by personal interview about acoustic phenomena related to their shunts.
Three hundred forty-seven patients were eligible for the survey, and 260 patients completed the questionnaire. Twenty-nine patients (11.2%) reported on noises raised by their shunts. All of them experienced short-lasting noises while changing body posture, mainly from a horizontal to an upright position, or while reclining the head. Most of the patients reported on soft sounds, but loud and even very loud noises occurred in some patients. Seventy-six percent of the patients were not bothered by these noises as they considered it as a normal part of the therapy or as proof that the shunt device was functioning. Modern valves with gravitational units are prone to produce noises in young adults, but nearly all valve types can evoke noises.
Noises caused by a shunt do occur in a considerable number of patients with shunts. One should be aware of this phenomenon, and these patients must be taken seriously 5).

2016

Rossi et al undertook a study to determine risk factors for shunt revision within their own patient population.
In this single-center retrospective cohort study, a database was created of all ventricular shunt operations performed at the authors’ institution from January 1, 2010, through December 2013. For each index shunt surgery, demographic, clinical, and procedural variables were assembled. An “index surgery” was defined as implantation of a new shunt or the revision or augmentation of an existing shunt system. Bivariate analyses were first performed to evaluate individual effects of each independent variable on shunt failure at 90 days and at 180 days. A final multivariate model was chosen for each outcome by using a backward model selection approach.
There were 466 patients in the study accounting for 739 unique (“index”) operations, for an average of 1.59 procedures per patient. The median age for the cohort at the time of the first shunt surgery was 5 years (range 0-35.7 years), with 53.9% males. The 90- and 180-day shunt failure rates were 24.1% and 29.9%, respectively. The authors found no variable-demographic, clinical, or procedural-that predicted shunt failure within 90 or 180 days.
In this study, none of the risk factors that were examined were statistically significant in determining shunt failure within 90 or 180 days. Given the negative findings and the fact that all other risk factors for shunt failure that have been proposed in the literature thus far are beyond the control of the surgeon (i.e., nonmodifiable), the use of an institution’s or individual’s global shunt revision rate remains questionable and needs further evaluation before being accepted as a quality metric 6).

2015

A study aims to review the imaging findings of distal (thoracic and abdominal) complications related to ventriculo-peritoneal (VP), ventriculo-pleural (VPL), and ventriculo-atrial (VA) cerebrospinal fluid (CSF) shunt catheter placement. Institution review board-approved single-center study of patients with thoracic and abdominal CSF catheter-related complications on cross-sectional imaging examinations over a 14-year period was performed. Clinical presentation, patient demographics, prior medical history, and subsequent surgical treatment were recorded. The presence or absence of CSF catheter-related infection and/or acute hydrocephalus on cross-sectional imaging was also recorded. There were 81 distal CSF catheter-related complications identified on 47 thoracic or abdominal imaging examinations in 30 patients (age 5-80 years, mean 39.3 years), most often on CT (CT = 42, MRI = 1, US = 4). Complications included 38 intraperitoneal and 11 extraperitoneal fluid collections. Extraperitoneal collections included nine abdominal wall subcutaneous (SC) pseudocysts associated with shunt migration and obesity, an intrapleural pseudocyst, and a breast pseudocyst. There were also two large VPL-related pleural effusions, a fractured catheter in the SC tissues, and a large VA shunt thrombus within the right atrium. Ten patients (33.3 %) had culture-positive infection from CSF or shunt catheter samples. Ten patients (33.3 %) had features of temporally related acute or worsening hydrocephalus on neuroimaging. In four of these patients, the detection of thoracic and abdominal complications on CT preceded and predicted the findings of acute hydrocephalus on cranial imaging. Thoracic and abdominal complications of CSF shunts, as can be identified on CT, include shunt infection and/or obstruction, may be both multiple and recurrent, and may be predictive of concurrent acute intracranial problems 7).

2011

From January 1999 to December 2006, Korinek et al., conducted a prospective surveillance program for all neurosurgical procedures including reoperations and infections. Patients undergoing CSF shunt placement were retrospectively identified among patients labeled in the database as having a shunt as a primary or secondary intervention. Revisions of shunts implanted in another hospital or before the study period were excluded, as well as lumbo- or cyst-peritoneal shunts. Shunt complications were classified as mechanical dysfunction or infection. Follow-up was at least 2 years. Potential risk factors were evaluated using log-rank tests and stepwise Cox regression models.
During the 8-year surveillance period, a total of 14 275 patients underwent neurosurgical procedures, including 839 who underwent shunt placement. One hundred nineteen patients were excluded, leaving 720 study patients. Mechanical dysfunction occurred in 124 patients (17.2%) and shunt infection in 44 patients (6.1%). These 168 patients required 375 reoperations. Risk factors for mechanical dysfunction were atrial shunt, greater number of previous external ventriculostomies, and male sex; risk factors for shunt infection were previous CSF leak, previous revisions for dysfunction, surgical incision after 10 am, and longer operating time.
Shunt surgery still carries a high morbidity rate, with a mean of 2.2 reoperations per patient in 23.3% of patients. Our risk-factor data suggest methods for decreasing shunt-related morbidity, including peritoneal routing whenever possible and special attention to preventing CSF leaks after craniotomy or external ventriculostomy 8).

Case reports

James et al. describe 3 children who presented with progressively enlarging skin-covered solid masses over the shunt catheter in the neck/clavicular region. The authors reviewed the clinical, laboratory, pathological, radiographic, and follow-up data for all 3 patients and reviewed the literature on the subject. The patients had no clinical evidence of an infectious process. Surgical exploration revealed that masses were surrounding and encasing the shunt tubing to which they were strongly attached. Pathological studies of the tissues demonstrated varying degrees of exuberant chronically inflamed granulation tissues, interstitial fibrosis, and dystrophic calcification. One patient had associated thinning of the skin overlying the mass and subsequently developed ulceration. No infectious organisms were observed. The cerebrospinal fluid aspirates from the shunts did not yield any organisms. There has been no recurrence of the masses. The presence of a growing mass over the shunt tube in the neck or the chest region without clinical evidence of infection does not indicate that the mass should be treated with antibiotics and complete shunt removal. Rather, the mass can be cured by extirpation and with “bypass” new shunt tubing locally 9).
1)

Wong JM, Ziewacz JE, Ho AL, Panchmatia JR, Bader AM, Garton HJ, Laws ER, Gawande AA. Patterns in neurosurgical adverse events: cerebrospinal fluid shunt surgery. Neurosurg Focus. 2012 Nov;33(5):E13. doi: 10.3171/2012.7.FOCUS12179. Review. PubMed PMID: 23116093.
2)

Chari A, Czosnyka M, Richards HK, Pickard JD, Czosnyka ZH. Hydrocephalus shunt technology: 20 years of experience from the Cambridge Shunt Evaluation Laboratory. J Neurosurg. 2014 Jan 3. [Epub ahead of print] PubMed PMID: 24405071.
3)

Bermo M, Leung AS, Matesan M. A Case of Discontinued Proximal Limb of a Ventriculoperitoneal Shunt With Patent Fibrous Tract. Clin Nucl Med. 2016 Feb 24. [Epub ahead of print] PubMed PMID: 26914568.
4)

Kaestner S, Fraij A, Deinsberger W, Roth C. I can hear my shunt-audible noises associated with CSF shunts in hydrocephalic patients. Acta Neurochir (Wien). 2017 Apr 14. doi: 10.1007/s00701-017-3179-z. [Epub ahead of print] PubMed PMID: 28411322.
5)

Kaestner S, Fraij A, Deinsberger W, Roth C. I can hear my shunt-audible noises associated with CSF shunts in hydrocephalic patients. Acta Neurochir (Wien). 2017 Jun;159(6):981-986. doi: 10.1007/s00701-017-3179-z. Epub 2017 Apr 14. PubMed PMID: 28411322.
6)

Rossi NB, Khan NR, Jones TL, Lepard J, McAbee JH, Klimo P Jr. Predicting shunt failure in children: should the global shunt revision rate be a quality measure? J Neurosurg Pediatr. 2016 Mar;17(3):249-59. doi: 10.3171/2015.5.PEDS15118. Epub 2015 Nov 6. PubMed PMID: 26544083.
7)

Bolster F, Fardanesh R, Morgan T, Katz DS, Daly B. Cross-sectional imaging of thoracic and abdominal complications of cerebrospinal fluid shunt catheters. Emerg Radiol. 2015 Nov 26. [Epub ahead of print] PubMed PMID: 26610766.
8)

Korinek AM, Fulla-Oller L, Boch AL, Golmard JL, Hadiji B, Puybasset L. Morbidity of ventricular cerebrospinal fluid shunt surgery in adults: an 8-year study. Neurosurgery. 2011 Apr;68(4):985-94; discussion 994-5. doi: 10.1227/NEU.0b013e318208f360. PubMed PMID: 21221037.
9)

James HE, Postlethwait RA, Sandler ED. Solid noninfectious growing masses over cerebrospinal fluid shunts: report of 3 cases. J Neurosurg Pediatr. 2015 Jan 30:1-4. [Epub ahead of print] PubMed PMID: 25634820.

Increase in FLAIR Signal of the Fluid Within the Resection Cavity as Early Recurrence Marker: Also Valid for Brain Metastases?

Fluid attenuation inversion recovery (FLAIR), is a special inversion recovery sequence with long T1 to remove the effects of fluid from the resulting images.

The T1 time of the FLAIR pulse sequence is adjusted to the relaxation time of the component that should be suppressed. For fluid suppression the inversion time (long T1) is set to the zero crossing point of fluid, resulting in the signal being ‘erased’.
This type of sequence is particularly useful in the detection of subtle changes at the periphery of the hemispheres and in the periventricular region close to CSF.
upload.wikimedia.org_wikipedia_commons_thumb_8_88_gliomatosis_cerebri2.jpg_220px-gliomatosis_cerebri2.jpg
Axial fluid-attenuated inversion recovery MRI image demonstrating tumor-related infiltration involving lenticular nucleus.
The usefulness of FLAIR sequences has been evaluated in diseases of the central nervous system such as:
infarction
multiple sclerosis
head injuries, and others

Increase in FLAIR signal of the fluid within the resection cavity is described as a highly specific and early sign for tumor recurrence in gliomas.
An increase in FLAIR signal of the fluid within the resection cavity might be a highly specific and early sign of local tumor recurrence/tumor progression also for brain metastases 1).

Single dose gadolinium (Gd) enhanced fluid-attenuated inversion recovery (FLAIR) is helpful for visualizing superficial parenchymal metastases.

Subarachnoid hemorrhage

Cerebral MRI may be proposed if the patient’s clinical condition allows it. FLAIR imaging is more sensitive than CT to demonstrate a subarachnoid hemorrhage and offers greater degrees of sensitivity for the diagnosis of restricted subarachnoid hemorrhage in cortical sulcus 2).

Low grade glioma

Fluid-attenuated inversion-recovery (FLAIR) imaging has established its utility in neuroimaging.
Bynevelt et al.propose this imaging sequence as a replacement for proton density image (PD) and T2-weighted spin-echo sequences in the follow-up of low-grade glioma.
Magnetic resonance imaging (MRI) with T2-weighted and Fluid Attenuated Inversion Recovery (FLAIR) images best delineates the extent of insular glioma infiltration, which can be limited to the insular lobe (Yasargil type 3a) or reach the perisylvian opercula (type 3b) and other paralimbic areas, namely the orbitofrontal and temporopolar regions (type 5), with or without involvement of core limbic structures 3).
MRI examinations of 18 patients with such tumours were reviewed by three neuroradiologists and a neurosurgeon. FLAIR was found to be superior for appreciation of the lesion (91% of studies) and for demonstration of its margin (92%). FLAIR was also better at showing different tumour components, particularly in regions difficult to demonstrate in some planes, such as the vertex in axial imaging. The sequence also defines the postoperative cavity, shows the least amount of susceptibility effect associated with surgical clips, and demonstrates local spread (to white matter tracts, subependymal and capsular) more distinctly.
FLAIR can replace PD and T2-weighted spin-echo imaging in radiological follow-up of low-grade glioma 4).
Lee et al. that measures of spatial diversity from point pattern analysis of intensity habitats from T1 post-contrast and T2 fluid-attenuated inversion recovery images are associated with both tumor subtype status and 12-month survival status and may therefore be useful indicators of patient prognosis, in addition to providing potential guidance for molecularly-targeted therapies in Glioblastoma multiforme 5).

http://www.intechopen.com/source/html/45292/media/fig1.png
A, B,C: Preoperative FLAIR MR images of a low grade glioma infiltrating the left operculo-insular region and the fronto-orbital, including the perforated substance (white arrow), temporopolar and hyppocampal regions, type 5 B of Yasargil classification (Yasargil et al, 1992). D: Postoperative T1 gadolinium-weighted and E,F: Postoperative FLAIR MR images, showing the subtotal removal of the lesion. The boundaries of the resection are set based on anatomical (perforated substance, white arrow) as well as neurofunctional (subcallosal fasciculus, yellow arrow; inferior occipitofrontal fasciculus, green arrow; arcuate fasciculus, blue arrow) criteria.

A study supports the established association between extent of resection (EOR) and survival and presents additional data that pushing the boundary of a conventional 100% resection by the additional removal of a significant portion of the FLAIR abnormality region, when safely feasible, may result in the prolongation of survival without significant increases in overall or neurological postoperative morbidity. Additional supportive evidence is warranted 6).

1) Bette S, Gempt J, Wiestler B, Huber T, Specht H, Meyer B, Zimmer C, Kirschke JS, Boeckh-Behrens T. Increase in FLAIR Signal of the Fluid Within the Resection Cavity as Early Recurrence Marker: Also Valid for Brain Metastases? Rofo. 2017 Jan;189(1):63-70. doi: 10.1055/s-0042-119686. PubMed PMID: 28002859.
2) Edjlali M, Rodriguez-Régent C, Hodel J, Aboukais R, Trystram D, Pruvo JP, Meder JF, Oppenheim C, Lejeune JP, Leclerc X, Naggara O. Subarachnoid hemorrhage in ten questions. Diagn Interv Imaging. 2015 Jul-Aug;96(7-8):657-66. doi: 10.1016/j.diii.2015.06.003. Epub 2015 Jul 2. PubMed PMID: 26141485.
3) Yasargil, MG.; von Ammon, K.; Cavazos, E.; Doczi, T.; Reeves, JD. & Roth, P. (1992). Tumors of the limbic and paralimbic systems. Acta Neurochirurgica, Vol.116, No.2-4, (March 1992), pp.147-149, ISSN 0001-6268
4) Bynevelt M, Britton J, Seymour H, MacSweeney E, Thomas N, Sandhu K. FLAIR imaging in the follow-up of low-grade gliomas: time to dispense with the dual-echo? Neuroradiology. 2001 Feb;43(2):129-33. PubMed PMID: 11326557.
5) Lee J, Narang S, Martinez J, Rao G, Rao A. Spatial Habitat Features Derived from Multiparametric Magnetic Resonance Imaging Data Are Associated with Molecular Subtype and 12-Month Survival Status in Glioblastoma Multiforme. PLoS One. 2015 Sep 14;10(9):e0136557. doi: 10.1371/journal.pone.0136557. eCollection 2015. PubMed PMID: 26368923.
6) Li YM, Suki D, Hess K, Sawaya R. The influence of maximum safe resection of glioblastoma on survival in 1229 patients: Can we do better than gross-total resection? J Neurosurg. 2015 Oct 23:1-12. [Epub ahead of print] PubMed PMID: 26495941.