Cisternal Score: A Radiographic Score to Predict Ventriculoperitoneal Shunt Requirement in Aneurysmal Subarachnoid Hemorrhage

Neurosurgery 93:75–83, 2023

Persistent hydrocephalus requiring a ventriculoperitoneal shunt (VPS) can complicate the management of aneurysmal subarachnoid hemorrhage (aSAH). Identification of high-risk patients may guide external ventricular drain management.

OBJECTIVE: To identify early radiographic predictors for persistent hydrocephalus requiring VPS placement. METHODS: In a 2-center retrospective study, we compared radiographic features on admission noncontrast head computed tomography scans of patients with aSAH requiring a VPS to those who did not, at 2 referral academic centers from 2016 through 2021. We quantified blood clot thickness in the basal cisterns including interpeduncular, ambient, crural, prepontine, interhemispheric cisterns, and bilateral Sylvian fissures. We then created the cisternal score (CISCO) using features that were significantly different between groups.

RESULTS: We included 229 survivors (mean age 55.6 years [SD 13.1]; 63% female) of whom 50 (22%) required VPS. CISCO was greater in patients who required a VPS than those who did not (median 4, IQR 3-6 vs 2, IQR 1-4; P < .001). Higher CISCO was associated with higher odds of developing persistent hydrocephalus with VPS requirement (odds ratio 1.6 per point increase, 95% CI 1.34-1.9; P < .001), independent of age, Hunt and Hess grades, and modified GRAEB scores. CISCO had higher accuracy in predicting VPS requirement (area under the curve 0.75, 95% CI 0.68-0.82) compared with other predictors present on admission.

CONCLUSION: Cisternal blood clot quantification on admission noncontrast head computed tomography scan is feasible and can be used in predicting persistent hydrocephalus with VPS requirement in patients with aSAH. Future prospective studies are recommended to further validate this tool.

Effect of topical and intraventricular antibiotics used during ventriculoperitoneal shunt insertion on the rate of shunt infection—a meta‐analysis

Acta Neurochirurgica (2022) 164:1793–1803

The ventriculoperitoneal shunt is one of the most commonly performed neurosurgical procedures. One of the avoidable complications of shunt surgery is shunt infection. This PRISMA-compliant meta-analysis analysed the effectiveness of topical and/or intraventricular antibiotics in preventing shunt infections in patients undergoing shunt surgery.

Methods Four databases were searched from inception to 30th June 2021. Only original articles comparing the rate of shunt infection with and without antibiotics were included. Random-effects meta-analysis was used to compare the effect of the use of antibiotics in preventing infection and subgroup analysis for finding differences in various antibiotics.

Results The rate of shunt infection was 2.24% (53 out of 2362) in the topical antibiotic group in comparison to 5.24% (145 out of 2764) in the control group (p = 0.008). Subgroup analysis revealed that there is no significant difference between the antibiotics used.

Conclusions Our meta-analysis found that the risk of shunt infection is significantly reduced with the use of topical and intraventricular antibiotics without any serious adverse effect. No side effects of topical or intraventricular antibiotics were reported in the included studies. Further prospective studies are required to establish the safety and optimal dosage of topical antibiotics for them to be used routinely in neurosurgical practice. They can be used in patients at high risk of developing shunt infections till such studies are available.

Cerebrospinal fluid shunting protocol for idiopathic intracranial hypertension for an improved revision rate

J Neurosurg 136:1790–1795, 2022

Cerebrospinal fluid (CSF) shunting in idiopathic intracranial hypertension (IIH) is associated with high complication rates, primarily because of the technical challenges that are related to small ventricles and a large body habitus. In this study, the authors report the benefits of a standardized protocol for CSF shunting in patients with IIH as relates to shunt revisions.

METHODS This was a retrospective study of consecutive patients with IIH who had undergone primary insertion of a CSF shunt between January 2014 and December 2020 at the authors’ hospital. In July 2019, they implemented a surgical protocol for shunting in IIH. This protocol recommended IIH shunt insertion by neurosurgeons with expertise in CSF disorders, a frontal ventriculoperitoneal (VP) shunt with an adjustable gravitational valve and integrated intracranial pressure monitoring device, frameless stereotactic insertion of the ventricular catheter, and laparoscopic insertion of the peritoneal catheter. Thirty-day revision rates before and after implementation of the protocol were compared in order to assess the impact of standardizing shunting for IIH on shunt complications.

RESULTS The 81 patients included in the study were predominantly female (93%), with a mean age of 31 years at primary surgery and mean body mass index (BMI) of 37 kg/m2. Forty-five patients underwent primary surgery prior to implementation of the protocol and 36 patients after. Overall, 12 (15%) of 81 patients needed CSF shunt revision in the first 30 days, 10 before and 2 after introduction of the protocol. This represented a significant reduction in the early revision rate from 22% to 6% after the protocol (p = 0.036). The most common cause of shunt revision for the whole cohort was migration or misplacement of the peritoneal catheter, occurring in 6 of the 12 patients. Patients with a higher BMI were significantly more likely to have a shunt revision within 30 days (p = 0.022).

CONCLUSIONS The Birmingham standardized IIH shunt protocol resulted in a significant reduction in revisions within 30 days of primary shunt surgery in patients with IIH. The authors recommend standardization for shunting in IIH as a method for improving surgical outcomes. They support the notion of subspecialization for IIH shunts, the use of a frontal VP shunt with sophisticated technology, and laparoscopic insertion of the peritoneal end. https:

Prediction of Shunt Responsiveness in Suspected Patients With Normal Pressure Hydrocephalus Using the Lumbar Infusion Test: A Machine Learning Approach

Neurosurgery 90:407–418, 2022

Machine learning (ML) approaches can significantly improve the classical Rout -based evaluation of the lumbar infusion test (LIT) and the clinical management of the normal pressure hydrocephalus.

OBJECTIVE: To develop a ML model that accurately identifies patients as candidates for permanent cerebral spinal fluid shunt implantation using only intracranial pressure and electrocardiogram signals recorded throughout LIT.

METHODS: This was a single-center cohort study of prospectively collected data of 96 patients who underwent LIT and 5-day external lumbar cerebral spinal fluid drainage (external lumbar drainage) as a reference diagnostic method. A set of selected 48 intracranial pressure/ electrocardiogram complex signal waveform features describing nonlinear behavior, wavelet transform spectral signatures, or recurrent map patterns were calculated for each patient. After applying a leave-one-out cross-validation training–testing split of the data set, we trained and evaluated the performance of various state-of-the-art ML algorithms.

RESULTS: The highest performing ML algorithm was the eXtreme Gradient Boosting. This model showed a good calibration and discrimination on the testing data, with an area under the receiver operating characteristic curve of 0.891 (accuracy: 82.3%, sensitivity: 86.1%, and specificity: 73.9%) obtained for 8 selected features. Our ML model clearly outperforms the classical Rout based manual classification commonly used in clinical practice with an accuracy of 62.5%.

CONCLUSION: This study successfully used the ML approach to predict the outcome of a 5-day external lumbar drainage and hence which patients are likely to benefit from permanent shunt implantation. Our automated ML model thus enhances the diagnostic utility ofLIT in management.

Permanent Cerebrospinal Fluid Diversion in Adults With Posterior Fossa Tumors: Incidence and Predictors

 

Neurosurgery 89:987–996, 2021

Posterior fossa tumors (PFTs) can cause hydrocephalus. Hydrocephalus can persist despite resection of PFTs in a subset of patients requiring permanent cerebrospinal fluid (CSF) diversion. Characteristics of this patient subset are not well defined.

OBJECTIVE: To define preoperative and postoperative variables that predict the need for postoperative CSF diversion in adult patients with PFTs.

METHODS: We surveyed the CNS (Central Nervous System) Tumor Outcomes Registry at Emory (CTORE) for patients who underwent PFT resection at 3 tertiary-care centers between 2006 and 2019. Demographic, radiographic, perioperative, and dispositional data were analyzed using univariate and multivariate models.

RESULTS:We included 617 patients undergoing PFT resection for intra-axial (57%) or extraaxial (43%) lesions. Gross total resection was achieved in 62% of resections. Approximately 13% of patients required permanent CSF diversion/shunting. Only 31.5% of patients who required pre- or intraop external ventricular drain (EVD) placement needed permanent CSF diversion. On logistic regression, size, transependymal flow, use of perioperative EVD, postoperative intraventricular hemorrhage (IVH), and surgical complications were predictors of permanent CSF diversion. Preoperative tumor size was only independent predictor of postoperative shunting in patients with subtotal resection. In patients with intra-axial tumors, transependymal flow (P = .014), postoperative IVH (P = .001), surgical complications (P = .013), and extent of resection (P = .03) predicted need for shunting. In extra-axial tumors, surgical complications were the major predictor (P = .022).

CONCLUSION: Our study demonstrates that presence of preoperative hydrocephalus in patients with PFT does not necessarily entail the need for permanent CSF diversion. We report the major predictive factors for needing permanent CSF diversion.

Comparison Between Flow-Regulated and Gravitational Shunt Valves in the Treatment of Normal Pressure Hydrocephalus: Flow-Grav Study

Neurosurgery 89:413–419, 2021

Normal pressure hydrocephalus (NPH) is frequently treated with ventriculoperitoneal shunt (VPS) surgery. However, VPS implantation can lead to overdrainage and complications such as headaches, hygroma, and subdural hematoma due to a siphon effect in an upright position. Gravitational valves prevent overdrainage through positiondependent adjustment of valve resistance. Flow-regulated valves that increase resistance in presence of high cerebrospinal fluid flow may provide similar protection against overdrainage and present an alternative to gravitational valves.

OBJECTIVE: To compare gravitational and flow-regulated shunt valves in patients with symptomatic NPH.

METHODS: We performed a retrospective analysis of 97 patients suffering from NPH who underwent VPS implantation with a gravitational or a flow-regulated valve. The primary endpoint was the occurrence of hygroma or subdural hematoma. Secondary endpoints were neurological outcome (Kiefer score, Stein and Langfitt score, and NPH recovery rate), frequency of valve adjustments, and reoperations.

RESULTS: No significant differences in the occurrence of hygroma and subdural hematoma (11.4% for flow-regulated valves vs 5.7% for gravitational valves, P = .462) or response to treatment (77.3% vs 81.1%, P = .802) were found. Patients with flow-regulated valves required fewer valve adjustments (1.12 vs 2.02, P < .001) to reach their optimal neurological outcome and underwent fewer surgical revisions (11.4% vs 28.3%, P = .047).

CONCLUSION: Our data suggest that shunt therapy in NPH patients with a flow-regulated instead of a gravitational valve is safe and effective with a comparable clinical outcome and risk of overdrainage complications. Moreover, patients with flow-regulated valves may need fewer valve adjustments and reoperations.

Freehand stereotactic ventricular catheter insertion for ventriculoperitoneal shunts based on individualized radio-anatomical landmarks

Acta Neurochirurgica (2021) 163:1103–1112

The accurate placement of the ventricular catheter (VC) is critical in reducing the incidence of proximal failure of ventriculoperitoneal shunts (VPSs). The standard freehand technique is based on validated external anatomical landmarks but remains associated with a relatively high rate of VC malposition. Already proposed alternative methods have all their specific limitations. Herein, we evaluate the accuracy of our adapted freehand technique based on an individualized radio-anatomical approach. Reproducing the preoperative imaging on the patient’s head using common anatomical landmarks allows to define stereotactic VC coordinates to be followed at surgery.

Material and methods Fifty-five consecutive patients treated with 56 VPS between 11/2005 and 02/2020 fulfilled the inclusion criteria of this retrospective study. Burr hole coordinates, VC trajectory, and length were determined in all cases on preoperative computed tomography (CT) scan and were accurately reported on patients’ head. The primary endpoint was to evaluate VC placement accuracy. The secondary endpoint was to evaluate the rate and nature of postoperative VC-related complications.

Results Our new technique was applicable in all patients and no VC-related complications were observed. Postoperative imaging showed VC optimally placed in 85.7% and sub-optimally placed in 14.3% of cases. In all procedures, all the holes on the VC tip were found in the ventricular system.

Conclusions This simple individualized technique improves the freehand VC placement in VPS surgery, making its accuracy comparable to that of more sophisticated and expensive techniques. Further randomized controlled studies are required to compare our results with those of the other available techniques.

Free-hand stereotactic ventricular catheter insertion technique based on radio-anatomical landmarks

Acta Neurochirurgica (2021) 163:1097–1102

Accurate ventricular catheter (VC) placement plays an important role in reducing the risk of ventriculoperitoneal shunt failure. Free-hand VC insertion is associated with a significant misplacement rate. Consequently, several expensive alternative methods that are unfortunately not available worldwide have been used. To overcome these limitations, we developed a simple surgical technique based on radio-anatomical landmarks aimed at reducing VC’s misplacements.

Method We reproduce the preoperative imaging on the patient’s head using common anatomical landmarks. This allows defining stereotactic VC coordinates to be followed during the surgical procedure.

Conclusion This simple and cost-effective method improves VC insertion accuracy.

The Role of Prophylactic Intraventricular Antibiotics in Reducing the Incidence of Infection and Revision Surgery in Pediatric Patients Undergoing Shunt Placement

Neurosurgery 88(2)2021: 301–305

Ventriculoperitoneal shunt placement remains the primary treatment modality for children with hydrocephalus. However, morbidity and revision surgery secondary to infection remains high, even while using antibiotic-impregnated shunts.

OBJECTIVE: To determine whether intraoperative injection of antibiotics is independently associated with reduced rates of infection and revision surgery in children undergoing shunt placement.

METHODS: This is an analysis of a prospectively collected, multicenter, shunt-specific neurosurgical registry consisting of data from over 100 hospitals collected between 2016 and 2017. All patients under 18 yr of age undergoing first-time shunt placement for the definitive treatment of hydrocephaluswere included. The primary exposure of interest was injection of intraventricular antibiotics into the shunt catheter following shunt placement and prior to closure. The use of additional surgical adjuncts, such as antibiotic-impregnated shunts, stereotactic guidance, and endoscopy was collected. The primary outcome metric was the need for additional intervention because of an infection.

RESULTS: A total of 2007 pediatric patients undergoing shunt placement for hydrocephalus were identified. Postoperatively, 97 (4.8%) patients had additional intervention secondary to infection. In a multivariable regression model controlling for patient characteristics, etiology of hydrocephalus, prior temporizing measures, and placement of an antibiotic-impregnated shunt, injection of intraventricular antibiotics was associated with a significant reduction in postoperative infections (odds ratio = 0.29, 95% CI: 0.04-0.89, P=.038). Of those receiving intraventricular antibiotics, only 2 (0.38%)went on to undergo re-intervention due to infection.

CONCLUSION: These data suggest that for this select group of patients, use of intraventricular antibiotics was associated with decreased rates of re-intervention secondary to infection.

Revision and complication rates in adult shunt surgery

Acta Neurochirurgica (2021) 163:447–454

CSF diversion with shunt placement is frequently associated with need for later revisions as well as surgical complications. We sought to review revision and complication rates following ventriculoperitoneal, ventriculoatrial and cystoperitoneal shunt placement in adult patients, and to identify potential risk factors for revision surgery and postoperative complications.

Method Included patients were adults (≥ 18 years) who underwent primary shunt insertion at St. Olavs Hospital in Trondheim, Norway, from 2008 through 2017. The electronic medical records and diagnostic imaging from all hospitals in our catchment area were retrospectively reviewed. Follow-up ranged from 1 to 11 years. Complications were graded according to the Landriel Ibañez classification system.

Results Of the 227 patients included, 47 patients (20.7%) required revision surgery during the follow-up. In total, 90 revision surgeries were performed during follow-up. The most common cause for the first revision was infection (5.7%) and for all revisions proximal occlusion (30.0%). A total of 103 patients (45.4%) experienced ≥ 1 complication(s). Mild to moderate complications (grade I and II) were detected in 35.0% of all procedures. Severe or fatal complications (grade III and IV) were observed in 8.2% of all procedures. Urinary tract infections and pneumonia were common postoperatively (13.9% and 7.3%, respectively), and the most common IIb complication was shunt misplacement (proximally or distally). Two out of fourteen deaths within 30 days were directly associated with surgery. We did not find that aetiology/indication, age or gender influenced the occurrence of revision surgery or a grade III or IV complication.

Conclusions Shunt surgery continues to be a challenge both in terms of revision rates and procedure-related complications. However, the prediction of patients at risk remains difficult. A multidimensional focus is probably needed to reduce risks.

Ultra-low-pressure hydrocephalic state in NPH: benefits of therapeutic siphoning with adjustable antigravity valves

Acta Neurochirurgica (2020) 162:2967–2974

Idiopathic normal-pressure hydrocephalus (NPH) is a condition of the elderly treated by ventriculoperitoneal shunt (VP) insertion. A subset of NPH patients respond only temporarily to shunt insertion despite low valve opening pressure. This study aims to describe our experience of patients who benefit from further CSF drainage by adding adjustable antigravity valves and draining CSF at ultra-low pressure.

Methods Single-centre retrospective case series of patients undergoing shunt valve revision from an adjustable differential pressure valve with fixed antigravity unit to a system incorporating an adjustable gravitational valve (Miethke proSA). Patients were screened from a database of NPH patients undergoing CSF diversion over 10 consecutive years (April 2008– April 2018). Clinical records were retrospectively reviewed for interventions and clinical outcomes.

Results Nineteen (10F:9M) patients underwent elective VP shunt revision to a system incorporating an adjustable gravitational valve. Mean age 77.1 ± 7.1 years (mean ± SD). Eleven patients (58%) showed significant improvement in walking speed following shunt revision. Fourteen patients/carers (74%) reported subjective improvements in symptoms following shunt revision.

Conclusions Patients presenting symptoms relapse following VP shunting may represent a group of patients with ultra-low pressure hydrocephalus, for whom further CSF drainage may lead to an improvement in symptoms. These cases may benefit from shunt revision with an adjustable gravitational valve, adjustment of which can lead to controlled siphoning of CSF and drain CSF despite ultra-low CSF pressure.

Diagnostic Accuracy of Non-Invasive Thermal Evaluation of Ventriculoperitoneal Shunt Flow in Shunt Malfunction

Neurosurgery 87:939–948, 2020

Thermal flow evaluation (TFE) is a non-invasive method to assess ventriculoperitoneal shunt function. Flow detected by TFE is a negative predictor of the need for revision surgery. Further optimization of testing protocols, evaluation in multiple centers, and integration with clinical and imaging impressions prompted the current study.

OBJECTIVE: To compare the diagnostic accuracy of 2 TFE protocols, with micropumper (TFE+MP) or without (TFE-only), to neuro-imaging in patients emergently presenting with symptoms concerning for shunt malfunction.

METHODS: We performed a prospective multicenter operator-blinded trial of a consecutive series of patients who underwent evaluation for shunt malfunction. TFE was performed, and preimaging clinician impressions and imaging results were recorded. The primary outcome was shunt obstruction requiring neurosurgical revision within 7 d. Noninferiority of the sensitivity of TFE vs neuro-imaging for detecting shunt obstruction was tested using a prospectively determined a priori margin of −2.5%.

RESULTS: We enrolled 406 patients at 10 centers. Of these, 68/348 (20%) evaluated with TFE+MP and 30/215 (14%) with TFE-only had shunt obstruction. The sensitivity for detecting obstruction was 100% (95% CI: 88%-100%) for TFE-only, 90% (95% CI: 80%-96%) for TFE+MP, 76% (95% CI: 65%-86%) for imaging in TFE+MP cohort, and 77%(95% CI: 58%- 90%) for imaging in the TFE-only cohort. Difference in sensitivities between TFE methods and imaging did not exceed the non-inferiority margin.

CONCLUSION: TFE is non-inferior to imaging in ruling out shunt malfunction and may help avoid imaging and other steps. For this purpose, TFE only is favored over TFE+MP.

Ventriculostomy with subsequent ventriculoperitoneal shunt placement after subarachnoid hemorrhage: the effect of implantation site on postoperative complications

Acta Neurochirurgica (2020) 162:1831–1836

Patients suffering from aneurysmal subarachnoid hemorrhage (SAH) with shunt-dependent hydrocephalus require subsequent placement of a ventriculoperitoneal shunt (VPS) after ventriculostomy. However, in patients with previous ventriculostomy, the site for proximal VPS catheter placement is still controversial.We investigated the effect of catheter placement on postoperative complications by analyzing patients with ventriculostomy and subsequent VPS placement after SAH.

Methods From January 2004 to December 2018, 164 of 1128 patients suffering from SAH underwent subsequent VPS placement after ventriculostomy in the authors’ institution. Patients were divided into two groups according to the position of the ventriculostomy and the site of the proximal VPS catheter (“same site” group versus “contralateral site” group). VPS-related infectious and bleeding complications following VPS placement were assessed and analyzed.

Results Overall, VPS-related infections occurred in 11 of the 164 patients (7%). Furthermore, five of the 164 patients (3%) suffered from VPS-related hemorrhage. However, VPS infection rate was lower 5% (6/115) in the same site compared to 10% (5/49) in the contralateral site group, although without reaching statistical significance (OR = 0.48 (0.14, 1.67) 95% confidence interval, p = 0.3). VPS-related hemorrhage rate did not differ significantly between patients in the same site group (3.5%, 4/115) and the contralateral site group (2.0%, 1/49; OR = 1.73 (0.18, 15.9), p = 1.0).

Conclusions Our study suggests that the use of the ventriculostomy site for VPS placement does not significantly increase the risk of either VPS-related infections or VPS-related hemorrhages.

Effect of fixed-setting versus programmable valve on incidence of shunt revision after ventricular shunting for idiopathic normal pressure hydrocephalus

J Neurosurg 133:564–572, 2020

Although ventricular shunting is an effective therapy for idiopathic normal pressure hydrocephalus (iNPH), the effect of shunt valve type on the incidence of revision surgery is not well defined. To address this issue, shunt revision rates between patients with iNPH receiving a fixed-setting valve (FSV) versus a programmable valve (PV) were compared.

METHODS Patients with iNPH treated with ventricular shunting between 2001 and 2017 were included for analysis. The incidence of shunt revision was noted and risk factors for revision were identified using a Cox proportional hazards model. Costs associated with admission for ventricular shunt procedures were obtained from the Vizient national database.

RESULTS There were 348 patients included for analysis, with 98 patients (28.1%) receiving a PV. Shunt revision occurred in 73 patients (21.0%), with 12 patients (3.4%) undergoing multiple revisions. Overall revision rates were lower in patients receiving a PV (13.3% vs 24.0%; p = 0.027), as was the incidence of multiple revisions (0.0% vs 4.8%; p = 0.023). Patients with initial placement of an FSV were also more likely to undergo valve exchange during follow-up (12.4% vs 2.0%; p = 0.003). Patients with a PV were less likely to undergo revision due to persistent symptoms without obstruction (2.0% vs 8.8%; p = 0.031) and distal obstruction (1.0% vs 6.8%; p = 0.030). In a multivariate Cox proportional hazards model, initial placement of a PV was associated with reduced risk of revision due to persistent symptoms without obstruction (OR 0.27, 95% CI 0.04–0.93; p = 0.036). PVs were associated with more frequent shunt series (1.3 vs 0.6; p < 0.001) and head CT scans (3.6 vs 2.7; p = 0.038) during follow-up. There was no significant difference in mean total costs between patients receiving an FSV and a PV ($24,282.50 vs $24,396.90; p = 0.937).

CONCLUSIONS The authors’ results suggest that PVs lead to reduced rates of shunt revision in patients with iNPH, and decreased risk of revision due to persistent symptoms of iNPH, thereby justifying the higher upfront cost of PVs despite similar overall treatment costs between these devices.

 

Clinical outcomes of normal pressure hydrocephalus in 116 patients: objective versus subjective assessment

J Neurosurg 132:1757–1763, 2020

Objective assessment tests are commonly used to predict the response to ventriculoperitoneal (VP) shunting in patients with normal pressure hydrocephalus (NPH). Whether subjective reports of improvement after a lumbar drain (LD) trial can predict response to VP shunting remains controversial. The goal in this study was to compare clinical characteristics, complication rates, and shunt outcomes of objective and subjective LD responders who underwent VP shunt placement.

METHODS This was a retrospective review of patients with NPH who underwent VP shunt placement after clinical improvement with the LD trial. Patients who responded after the LD trial were subclassified into objective LD responders and subjective LD responders. Clinical characteristics, complication rates, and shunt outcomes between the 2 groups were compared with chi-square test of independence and t-test.

RESULTS A total of 116 patients received a VP shunt; 75 were objective LD responders and 41 were subjective LD responders. There was no statistically significant difference in patient characteristics between the 2 groups, except for a shorter length of stay after LD trial seen with subjective responders. The complication rates after LD trial and VP shunting were not significantly different between the 2 groups. Similarly, there was no significant difference in shunt response between objective and subjective LD responders. The mean duration of follow-up was 1.73 years.

CONCLUSIONS Reports of subjective improvement after LD trial in patients with NPH can be a reliable predictor of shunt response. The currently used objective assessment scales may not be sensitive enough to detect subtle changes in symptomatology after LD trial.

Natural history of ventriculomegaly in adults: a cluster analysis

J Neurosurg 132:741–748, 2020

Chronic ventriculomegaly in the absence of raised intracranial pressure (ICP) is a known entity in adult hydrocephalus practice. The natural history and indication for treatment is, however, poorly defined. A highly heterogeneous group, some adults with ventriculomegaly are asymptomatic, while others have life-threatening deteriorations. The authors hypothesized that the various presentations can be subtyped and represent different stages of decompensation. A cluster analysis was performed on a cohort of patients with chronic ventriculomegaly with the aim of elucidating typical clinical characteristics and outcomes in chronic ventriculomegaly in adults.

METHODS Data were collected from 79 patients with chronic ventriculomegaly referred to a single center, including demographics, presenting symptoms, and 24-hour ICP monitoring (ICPM). A statistical cluster analysis was performed to determine the presence of subgroups.

RESULTS Four main subgroups and one highly dissimilar group were identified. Patients with ventriculomegaly commonly have a perinatal event followed by one of four main presentations: 1) incidental ventriculomegaly with or without headache; 2) highly symptomatic presentation (including reduced consciousness) and raised ICP; 3) early presenting with symptoms of headache and nausea (with abnormal pulsatility); and 4) late presenting with features common to normal pressure hydrocephalus. Each symptomatic group has characteristic radiological features, ICPM, and responses to treatment.

CONCLUSIONS Cluster analysis has identified subgroups of adult patients with ventriculomegaly. Such groups may represent various degrees of decompensation. Surgical interventions may not be equally effective across the subgroups, presenting an avenue for further research. The identified subtypes provide further insight into the natural history of this lesser studied form of hydrocephalus.

Lumboperitoneal and Ventriculoperitoneal Shunting for Idiopathic Intracranial Hypertension Demonstrate Comparable Failure and Complication Rates

Neurosurgery 86:272–280, 2020

Idiopathic intracranial hypertension results in increased intracranial pressure leading to headache and visual loss. This disease frequently requires surgical intervention through lumboperitoneal (LP) or ventriculoperitoneal (VP) shunting.

OBJECTIVE: To compare postoperative outcomes between LP and VP shunts, including failure and complication rates.

METHODS: A retrospective analysis was conducted using a national administrative database (MarketScan) to identify idiopathic intracranial hypertension (IIH) patients who underwent LP or VP shunting from 2007 to 2014. Multivariate logistic and Cox regressions were performed to compare rates of shunt failure and time to shunt failure between LP and VP shunts while controlling for demographics and comorbidities.

RESULTS: The analytic cohort included 1082 IIH patients, 347 of whom underwent LP shunt placement at index hospitalization and 735 of whom underwent VP shunt placement. Rates of shunt failure were similar among patients with LP and VP shunt (34.6% vs 31.7%; P=.382). Among patients who experienced shunt failure, the mean number of shunt failures was 2.1±1.6 and was similar between LP and VP cohorts. Ninety-day readmission rates, complication rates, and costs did not differ significantly between LP and VP shunts. Patients who experienced more than two shunt failures tended to have an earlier time to first shunt failure (hazard ratio 1.41; 95% confidence interval 1.08-1.85; P = .013).

CONCLUSION: These findings suggest that LP and VP shunts may have comparable rates of shunt failure and complication. Regardless of shunt type, earlier time to first shunt failure may be associated with multiple shunt failures.

Accuracy and safety of 1-day external lumbar drainage of CSF for shunt selection in patients with idiopathic normal pressure hydrocephalus

J Neurosurg 131:1011–1017, 2019

Three to five days of external lumbar drainage (ELD) of CSF is a test for ventriculoperitoneal shunt (VPS) selection in idiopathic normal pressure hydrocephalus (iNPH). The accuracy and complication rates of a shorter (1-day) ELD procedure were analyzed.

METHODS Data of patients with iNPH who underwent 1-day ELD to be selected to undergo VPS placement with a programmable valve in the period from 2005 to 2015 were reviewed. Patients experiencing VPS complications, valve malfunctioning, or with less than 1 year of follow-up were excluded. The ability of 1-day ELD to predict VPS outcome at 1- and 12-month follow-up was assessed by calculating sensitivity, specificity, and positive and negative predictive values.

RESULTS Of 93 patients who underwent 1-day ELD, 3 did not complete the procedure. Of the remaining 90 patients, 2 experienced transient nerve root irritation. Twenty-four patients had negative test outcomes and 66 had positive test out- comes. Nine negative-outcome patients had intraprocedural headache, which showed 37.5% sensitivity (95% confidence interval [CI] 19.5%–59.2%) and 100% specificity (95% CI 93.1%–100%) as predictors of negative 1-day ELD outcome. Sixty-eight patients (6 with negative and 62 with positive outcomes) underwent VPS insertion, which was successful in
0 and 58 patients, respectively, at 1-month follow-up. Test sensitivity and specificity in predicting surgical outcome at 1-month follow-up were 100% (95% CI 92.3%–100%) and 60% (95% CI 27.4%–86.3%), respectively, with 94.1% accu- racy (95% CI 85.6–98.4%). Among the 1-day ELD–positive patients, 2 showed no clinical benefit at 12 months follow-up. Test sensitivity and specificity in predicting surgical outcome at 12-month follow-up was 100% (95% CI 92.5%–100%) and 75.0% (95% CI 35.6%–95.5%), respectively, with 97.1% (95% CI 89.8%–99.6%) accuracy.

CONCLUSIONS One-day ELD is a reliable tool in iNPH management, with low complication risk and short trial duration. The test is very consistent in predicting who will have a positive outcome with VPS placement, given the high chance of successful outcome at 1- and 12-month follow-up; negative-outcome patients have a high risk of unsuccessful surgery. Intraprocedural headache is prognostic of 1-day ELD negative outcome.

Noninvasive Thermal Evaluation of Ventriculoperitoneal Shunt Patency and Cerebrospinal Fluid Flow Using a Flow Enhancing Device

Neurosurgery, Volume 85, Issue 2, August 2019, Pages 240–249

While a noninvasive flow determination would be desirable in the diagnosis of cerebrospinal fluid shunt malfunction, existing studies have not yet defined a role for thermal flow detection.

OBJECTIVE: To evaluate a revised test protocol using a micropumper designed to transiently enhance flow during thermal testing to determine whether thermal detection of flow is associated with progression to shunt revision surgery.

METHODS: Eighty-two unique tests were performed in 71 shunts. The primary outcome, need for revision within 7 d of testing, was compared with results of micropumper-augmented thermal flow detection. Statistical analysis was based on blind interpretation of test results and raw temperature data recorded during testing.

RESULTS: The test was sensitive (73%) and specific (68%) in predicting need for revision, with 5.6-fold higher probability of revision when flow was not detected. Negative predictive value in our sample was 94.2%. The probability of not requiring revision increased with increasing total temperature drop. Analysis of various possible thresholds showed that the optimal temperature cutoff may be lower than suggested by the manufacturer (0.125◦C vs 0.2◦C).

CONCLUSION: This is the first study to report a strong association between thermal flow evaluation and a clinical impression that a shunt is not malfunctioning. The current recommended threshold may increase the false positive rate unnecessarily, and as clinicians gain experience with the method, they may find value in examining the temperature curves themselves. Multicenter studies are suggested to further define a role for this diagnostic test.

Value of whole-body low-dose computed tomography in patients with ventriculoperitoneal shunts: a retrospective study

J Neurosurg 129:1598–1603, 2018

The gold standard for evaluation of ventriculoperitoneal (VP) shunt position, dislocation, or disconnection is conventional radiography. Yet, assessment with this modality can be challenging because of low image quality and can result in repetitive radiation exposure with high fluctuation in the radiation dose. Recently, CT-based radiation doses have been significantly reduced by using low-dose protocols. Thus, whole-body low-dose CT (LDCT) has become applicable for routine use in VP shunt evaluation. The authors here compared image quality and approximate radiation dose between radiography and LDCT in patients with implanted VP shunt systems.

METHODS Ventriculoperitoneal shunt systems have been investigated with LDCT scanning at the authors’ department since 2015. A consecutive series of 57 patients (70 investigations) treated between 2015 and 2016 was retrospectively assessed. A historical patient cohort that had been evaluated with radiography was compared with the LDCT patients in terms of radiation dose and image quality. Three independent observers evaluated projection of the valve pressure level and correct intraperitoneal position, as well as complete shunt projection, using a Likert-type scale of 1–5, where 1 indicated “not assessable” and 5 meant “assessable with high accuracy.” Descriptive statistics and the Mann-Whitney U-test were used for analysis.

RESULTS Twenty-seven radiographs (38.6%) and 43 LDCT scans (61.4%) were analyzed. The median dose-length product (DLP) of the LDCT scans was 100 mGy·cm (range 59.9–183 mGy·cm). The median total dose-area product (DAP) of the radiographic images was 3177 mGy·cm2 (range 641–13,833 mGy·cm2). The estimated effective dose (EED) was significantly lower with the LDCT scan (p < 0.001). The median EED was 4.93 and 1.90 mSv for radiographs and LDCT, respectively. Significantly better identification of the abdominal position of the distal shunt catheter was achieved with LDCT (p < 0.001). Simultaneously, significantly improved visualization of the entire shunt system was realized with this technique (p < 0.001). On the contrary, identification of the valve settings was significantly worse with LDCT (p < 0.001).

CONCLUSIONS Whole-body LDCT scanning allows good visualization of the distal catheter after VP shunt placement. Despite the fact that only a rough estimation of effective doses is possible in a direct comparison of LDCT and radiography, the data showed that shunt assessment via LDCT does not lead to greater radiation exposure. Thus, especially in difficult anatomical conditions, as in patients who have undergone multiple intraabdominal surgeries, have a high BMI, or are immobile, the use of LDCT shunt evaluation has high clinical value. Further data are needed to determine the value of LDCT for the evaluation of complications or radiation dose in pediatric patients.