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).


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

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

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

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

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

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

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

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

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

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.

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 adenomacerebrospinal 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.



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.

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.

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.

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).



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.

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.

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.

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.

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.
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