Ventriculoatrial Shunt Versus Ventriculoperitoneal Shunt: A Systematic Review and Meta-Analysis

Neurosurgery 94:903–915, 2024

Ventriculoperitoneal shunt (VPS) is usually the primary choice for cerebrospinal fluid shunting for most neurosurgeons, while ventriculoatrial shunt (VAS) is a second-line procedure because of historical complications. Remarkably, there is no robust evidence claiming the superiority of VPS over VAS. Thus, we aimed to compare both procedures through a meta-analysis.

METHODS: Following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, the authors systematically searched the literature for articles comparing VAS with VPS. The included articles had to detail one of the following outcomes: revisions, infections, shunt-related mortality, or complications. In addition, the cohort for each shunt model had to encompass more than 4 patients.

RESULTS: Of 1872 articles, 16 met our criteria, involving 4304 patients, with 1619 undergoing VAS and 2685 receiving VPS placement. Analysis of revision surgeries showed no significant difference between VAS and VPS (risk ratio [RR] = 1.10, 95% CI: 0.9-1.34; I 2 = 84%, random effects). Regarding infections, the analysis also found no significant difference between the groups (RR = 0.67, 95% CI: 0.36-1.25; I 2 = 74%, random effects). There was no statistically significant disparity between both methods concerning shunt-related deaths (RR = 2.11, 95% CI: 0.68-6.60; I 2 = 56%, random effects). Included studies after 2000 showed no VAS led to cardiopulmonary complications, and only 1 shunt-related death could be identified.

CONCLUSION: Both methods show no significant differences in procedure revisions, infections, and shunt-related mortality. The literature is outdated, research in adults is lacking, and future randomized studies are crucial to understand the profile of VAS when comparing it with VPS. The final decision on which distal site for cerebrospinal shunting to use should be based on the patient’s characteristics and the surgeon’s expertise.

Radionuclide shuntography for cerebrospinal fluid shunt flow evaluation in adults

J Neurosurg 140:621–626, 2024

Radionuclide shuntography (RS) performed using 99m Tc-DTPA injected into the reservoir of CSF shunts enables evaluation of CSF flow for suspected shunt malfunctions. The goal of this study was to report the authors’ institutional experience with RS and evaluate its utility and associated complications.

METHODS The authors retrospectively reviewed all RS studies performed between November 2003 and June 2022. Patients with shunted hydrocephalus who were ≥ 18 years of age were included. Patients undergoing RS for evaluation of Ommaya reservoirs were excluded. Demographics, hydrocephalus etiology, presenting symptoms, study results, subsequent management, complications, and intraoperative diagnoses were recorded. Chi-square tests were reported for categorical variables and standard 2 × 2 contingency methods were used for sensitivity/specificity analysis.

RESULTS The authors identified 211 RS procedures performed in 142 patients. The mean age at procedure was 55.6 ± 20.9 years (mean ± SD). Normal pressure hydrocephalus was the most common hydrocephalus etiology (37.0%), followed by congenital malformations (26.1%) and idiopathic intracranial hypertension (15.6%). Successful radionuclide injection was achieved in 207 studies (98.1%). Shunt patency was confirmed in 63.8% of successful injections, whereas malfunction was demonstrated in 27.1% and abnormally slow flow was seen in 9.2%. RS studies demonstrating shunt malfunction were more likely to result in subsequent revisions than were studies showing patency (86.6% vs 2.9%; p < 0.0001). The overall sensitivity and specificity of RS for detecting shunt malfunction was 92.3% and 96.2%, respectively. The median follow-up time was 29 months, with 151 cases having ≥ 6 months of follow-up. There were no complications or infections attributable to RS in this cohort.

CONCLUSIONS RS is a useful and safe tool in the workup of shunt malfunction.

 

Dorsum Sellae as Key Landmark in ETV With Disminished Prepontine Cistern

Operative Neurosurgery 26:188–195, 2024

One of the key aspects in the surgical technique of endoscopic third ventriculostomy (ETV) is the perforation of the floor of the third ventricle because of the high risk of injuring vital structures located in that region. According to the standard technique, this perforation should be performed in the midline halfway between mammillary bodies and the infundibular recess to avoid damage to the structures. This can be performed without excessive complications when the diameter of the prepontine cistern is wide. However, in situations where the diameter is reduced (defined in the literature as having a prepontine interval [PPI] ≤1 mm), the probability of complications increases exponentially. In this article, we propose using dorsum sellae as a key point to safely perform ETV in patients with a decreased PPI, guiding the trajectory and its marking using neuronavigation.

METHODS: A review was conducted on the latest 100 ETV procedures performed by our team in the past 5 years. The measurement of the PPI was conducted using archived preoperative MRI imaging studies, specifically between the dorsum sellae and the basilar artery. In cases where the PPI was ≤1 mm and, therefore, the use of the dorsum sellae was applied as a reference point, the technical results and procedural functions were documented.

RESULTS: In the cohort, 7 patients with a PPI ≤1 mm were identified. In all 7 cases, fenestration of the tuber cinereum was successfully performed without causing vascular damage or associated complications. ETV was successful in 6 patients, with only one experiencing ETV failure necessitating the placement of a ventriculoperitoneal shunt.

CONCLUSION: The utilization of the dorsum sellae as a reference point to perform ETV in reduced PPI constitutes a safe alternative to the classical technique.

Use of cortical volume to predict response to temporary CSF drainage in patients with idiopathic normal pressure hydrocephalus

J Neurosurg 139:1776–1783, 2023

Temporary drainage of CSF with lumbar puncture or lumbar drainage has a high predictive value for identifying patients with suspected idiopathic normal pressure hydrocephalus (iNPH) who may benefit from ventriculoperitoneal shunt insertion. However, it is unclear what differentiates responders from nonresponders. The authors hypothesized that nonresponders to temporary CSF drainage would have patterns of reduced regional gray matter volume (GMV) as compared with those of responders. The objective of the current investigation was to compare regional GMV between temporary CSF drainage responders and nonresponders. Machine learning using extracted GMV was then used to predict outcomes.

METHODS This retrospective cohort study included 132 patients with iNPH who underwent temporary CSF drainage and structural MRI. Demographic and clinical variables were examined between groups. Voxel-based morphometry was used to calculate GMV across the brain. Group differences in regional GMV were assessed and correlated with change in results on the Montreal Cognitive Assessment (MoCA) and gait velocity. A support vector machine (SVM) model that used extracted GMV values and was validated with leave-one-out cross-validation was used to predict clinical outcome.

RESULTS There were 87 responders and 45 nonresponders. There were no group differences in terms of age, sex, baseline MoCA score, Evans index, presence of disproportionately enlarged subarachnoid space hydrocephalus, baseline total CSF volume, or baseline white matter T2-weighted hyperintensity volume (p > 0.05). Nonresponders demonstrated decreased GMV in the right supplementary motor area (SMA) and right posterior parietal cortex as compared with responders (p < 0.001, p < 0.05 with false discovery rate cluster correction). GMV in the posterior parietal cortex was associated with change in MoCA (r 2 = 0.075, p < 0.05) and gait velocity (r 2 = 0.076, p < 0.05). Response status was classified by the SVM with 75.8% accuracy.

CONCLUSIONS Decreased GMV in the SMA and posterior parietal cortex may help identify patients with iNPH who are unlikely to benefit from temporary CSF drainage. These patients may have limited capacity for recovery due to atrophy in these regions that are known to be important for motor and cognitive integration. This study represents an important step toward improving patient selection and predicting clinical outcomes in the treatment of iNPH.

Neuronavigated foraminoplasty, shunt removal, and endoscopic third ventriculostomy in a 54‑year‑old patient with third shunt malfunction episode

Acta Neurochirurgica (2023) 165:3289–3296

The application of endoscopic third ventriculostomy (ETV) for the treatment of obstructive hydrocephalus in shunt malfunction represents a paradigm shift, as it allows hydrocephalus to be transformed from a chronic condition treated with an artificial device to a curable disease.

Methods We present a 54-year-old male with a diagnosis of idiopathic Sylvian aqueduct stenosis treated with shunt. The patient presented to our institution with symptoms of shunt malfunction and an increase in ventricular size on imaging, which was his third episode throughout his life. Through a right precoronal approach, with prior informed consent from the patient, we performed foraminoplasty, endoscopic third ventriculostomy, and finally removal of the shunt system.

Conclusion ETV shows promise as a viable treatment option for shunt malfunction in noncommunicating obstructive hydrocephalic patients. Its potential to avoid VPS-related complications, preserve physiological CSF circulation, and provide an alternative drainage pathway warrants further investigation.

Ventriculosinus shunt: a pilot study to investigate new technology to treat hydrocephalus and mimic physiological principles of cerebrospinal fluid drainage

J Neurosurg 139:1412–1419, 2023

Devices draining CSF to the intracranial venous sinus for the treatment of hydrocephalus have been tested in the past, and while clinically effective, have not shown efficacy in the long term. The majority of these devices become obstructed within 3 months due to endothelial overgrowth. In this study, the authors investigated a newly developed ventriculosinus (VS) shunt outlet device with the objective of showing it would remain patent for at least 6 months.

METHODS Twelve patients in need of shunting for hydrocephalus underwent an operation using the investigational device and were followed for 6 months to record patency of the shunt.

RESULTS In 10 patients, the shunt was patent at 6 months, with the outlet device remaining unobstructed. In the remaining 2 patients, one died just before reaching the 6-month endpoint, and in the other the outlet was misplaced during surgery and therefore ceased to function after 3 months. No occlusion of the internal jugular vein or thrombus formation was noted in any of the 12 cases.

CONCLUSIONS These findings indicate that the outlet device can remain patent and has the capability to mimic physiological drainage by diverting CSF to the intracranial sinus. Additional confirmation of its potential as part of a new VS shunt system and ultimately as a viable alternative for ventriculoperitoneal and ventriculoatrial shunting to reduce complication rates requires further clinical trials.

Retrospective comparison of long‑term functionality and revision rate of two different shunt valves in pediatric and adult patients

Acta Neurochirurgica (2023) 165:2541–2549

The most frequent therapy of hydrocephalus is implantation of ventriculoperitoneal shunts for diverting cerebrospinal into the peritoneal cavity. We compared two adjustable valves, proGAV and proGAV 2.0, for complications resulting in revision surgery.

Methods Four hundred patients undergoing primary shunt implantation between 2014 and 2020 were analyzed for overall revision rate, 1-year revision rate, and revision-free survival observing patient age, sex, etiology of hydrocephalus, implantation site, prior diversion of cerebrospinal fluid, and cause of revision.

Results All data were available of all 400 patients (female/male 208/192). Overall, 99 patients underwent revision surgery after primary implantation. proGAV valve was implanted in 283 patients, and proGAV 2.0 valves were implanted in 117 patients. There was no significant difference between the two shunt valves concerning revision rate (p = 0.8069), 1-year revision rate (p = 0.9077), revision-free survival (p = 0.6921), and overall survival (p = 0.3232). Regarding 1-year revision rate, we observed no significant difference between the two shunt valves in pediatric patients (40.7% vs 27.6%; p = 0.2247). Revision operation had to be performed more frequently in pediatric patients (46.6% vs 24.8%; p = 0.0093) with a significant higher number of total revisions with proGAV than proGAV 2.0 (33 of 59 implanted shunts [55.9%] vs. 8 of 29 implanted shunts [27.6%]; p = 0.0110) most likely due to longer follow-up in the proGAV-group. For this reason, we clearly put emphasis on analyzing results regarding 1-year revision rate.

Conclusion According to the target variables we analyzed, aside from lifetime revision rate in pediatric patients, there is no significant difference between the two shunt valves.

The Management of Hydrocephalus in Midline Posterior Fossa Cystic Collections

Neurosurgery 93:576–585, 2023

Hydrocephalus frequently occurs with midline posterior fossa cystic collections. The classification of this heterogeneous group of developmental anomalies, including Dandy–Walker malformation, persisting Blake’s pouch, retrocerebellar arachnoid cysts, and mega cisterna magna, is subject of debate. The absence of diagnostic criteria is confusing regarding the ideal management of PFCC-related hydrocephalus.

OBJECTIVE: To decipher the surgical strategy for the treatment of children with PFCC-related hydrocephalus through a retrospective analysis of the surgical outcome driven by their clinical and radiological presentation.

METHODS: This study enrolled patients operated of symptomatic PFCC-related hydrocephalus. Clinical and MRI features were examined, as well as the surgical outcome. Unbiased subgroup classification of the patients was performed with multiple component analysis as a function of imaging characteristics and hierarchical clustering on principal component. Outcome was assessed with binomial logistic regression and Kaplan–Meier analysis.

RESULTS: Fifty-four patients were included between 2007 and 2021. Multiple component analysis suggested that cerebellar and vermian hypoplasia, vermian rotation, basal–tentorial angle, and fastigial angle were strongly correlated. Hierarchical clustering and the distribution of the patients in the bidimensional plot showed the clear segregation of 3 major clusters, which correlated with the radiological diagnosis (P < .01). Binomial logistic regression and survival analysis showed that endoscopic third ventriculostomy was an effective treatment for patients with persisting Blake’s pouch, while failing to control hydrocephalus in most of patients with Dandy–Walker malformation.

CONCLUSION: Preoperative MRI in patients with PFCC-related hydrocephalus is essential to better define the diagnosis. The choice of treatment strategy notably relies on correct radiological diagnosis.

Initial Clinical Experience and Biomechanical Analysis of a Novel Gravity Unit–Assisted Valve (M.blue) in Pediatric Patients With Hydrocephalus

Neurosurgery 93:555–562, 2023

Overdrainage is a widely reported complication representing common indication for shunt revision. Despite recent advances in valve design, repeated shunt revisions represent burden on healthcare systems.

OBJECTIVE: To investigate the efficiency of a novel gravity unit–assisted programmable valve “M.blue” in pediatric hydrocephalus using clinical and biomechanical analyses.

METHODS: This retrospective single-center study included pediatric patients who received M.blue valve between April 2019 and 2021. Several clinical and biomechanical parameters were documented including complications and revision rates. Flow rate, functional assessment in vertical and horizontal positions, and extent of depositions inside valve were analyzed in explanted valves.

RESULTS: Thirty-seven M.blue valves in 34 pediatric patients with hydrocephalus (mean age 2.82 ± 3.91 years) were included. Twelve valves (32.4%) were explanted during a follow-up period of 27.3 ± 7.9 months. One-year survival rate of 89% and overall survival rate of 67.6% with a valve survival average of 23.8 ± 9.7 months were observed. Patients with explanted valves (n = 12) were significantly younger, with 0.91 ± 0.54 years of age in average (P= .004), and showed significantly more adjustments difficulties (P= .009). 58.3% of explanted valves showed deposits in more than 75% of the valve surface despite normal cerebrospinal fluid findings and were associated with dysfunctional flow rate in vertical, horizontal, or both positions.

CONCLUSION: The novel M.blue valve with integrated gravity unit is efficient in pediatric hydrocephalus with comparable survival rate. Deposits inside valves could affect its flow rate in different body positions and might lead to dysfunction or difficulties in valve adjustments.

Cerebral Microbleeds—Long-Term Outcome After Cerebrospinal Fluid Shunting in Idiopathic Normal Pressure Hydrocephalus

Neurosurgery 93:300–308, 2023

Cerebral microbleeds (CMBs) are common in idiopathic normal pressure hydrocephalus (INPH) and have been suggested as radiological markers of a brain prone to bleeding. The presence of CMBs might be relevant when selecting patients for shunt surgery.

OBJECTIVE: To evaluate whether CMBs increases long-term risk of hemorrhagic complications and mortality or affects outcomes after cerebrospinal fluid shunt surgery in a cohort of patients with INPH.

METHODS: One hundred and forty nine shunted patients with INPH (mean age, 73 years) were investigated with MRI (T2* or susceptibility-weighted imaging sequences) preoperatively. CMBs were scored with the Microbleed Anatomic Rating Scale. Patients were observed for a mean of 6.5 years (range 2 weeks to 13 years) after surgery. Hemorrhagic events and death were noted. Improvement in gait was evaluated 3 to 6 months after surgery.

RESULTS: At baseline, 74 patients (50%) had CMBs. During follow-up, 7 patients (5%) suffered a hemorrhagic stroke and 43 (29%) suffered a subdural hematoma/hygroma with a median time from surgery of 30.2 months (IQR 50). Overall, having CMBs was not associated with suffering a subdural hematoma/hygroma or hemorrhagic stroke during follow-up with 1 exception that an extensive degree of CMBs (≥50 CMB) was more common in patients suffering a hemorrhagic stroke (P = .03). CMBs were associated with increased mortality (P = .02, Kaplan-Meier, log-rank test). The presence of CMBs did not affect gait outcome (P = .28).

CONCLUSION: CMBs were associated with hemorrhagic stroke and mortality. CMBs do not seem to reduce the possibility of gait improvement after shunt surgery or contribute to the risk of hemorrhagic complications regarding subdural hematoma or hygroma.

Neuronavigated endoscopic aqueductoplasty with panventricular stent plus septostomy for isolated fourth ventricle in complex hydrocephalus and syringomyelia associated with myelomeningocele

Acta Neurochirurgica (2023) 165:2333–2338

Isolated fourth ventricle (IFV) is a challenging entity to manage. In recent years, endoscopic treatment for aqueductoplasty has been on the rise. However, in patients with complex hydrocephalus and distorted ventricular system, its implementation can be complex.

Methods We present a 3-year-old patient with myelomeningocele and postnatal hydrocephalus treated by ventriculoperitoneal shunt. In follow-up, a progressive IFV and isolated lateral ventricle with symptoms of the posterior fossa developed. An endoscopic aqueductoplasty (EA) with panventricular stent plus septostomy guided with neuronavigation was decided due to the complexity of the ventricular system.

Conclusion In IFV associated with complex hydrocephalus with distortion of the ventricular system, navigation can be of great help for planning and as a guide for performing EA

From white to blue light: evolution of endoscope-assisted intracranial tumor neurosurgery and expansion to intraaxial tumors

J Neurosurg 139:59–64, 2023

Intraoperative use of the endoscope to assist in visualization of intracranial tumor pathology has expanded with increasing surgeon experience and improved instrumentation. The authors aimed to study how advancements in endoscopic technology have affected the evolution of endoscope use, with particular focus on blue light–filter modification allowing for discrimination of fluorescent tumor tissue following 5-ALA administration.

METHODS A retrospective analysis of patients undergoing craniotomy for tumor resection at a single institution between February 2012 and July 2021 was performed. Patients were included if the endoscope was used for diagnostic tumor cavity inspection or therapeutic assistance with tumor resection following standard craniotomy and microsurgical tumor resection, with emphasis on those cases in which blue light endoscopy was used. Medical records were queried for patient demographics, operative reports describing the use of the endoscope and extent of resection, associations with tumor pathology, and postoperative outcomes. Preoperative and postoperative MR images were reviewed for radiographic extent of resection.

RESULTS A total of 52 patients who underwent endoscope-assisted craniotomy for tumor were included. Thirty patients (57.7%) were men and the average age was 52.6 ± 16.1 years. Standard white light endoscopes were used for assistance with tumor resection in 28 cases (53.8%) for tumors primarily located in the ventricular system, parasellar region, and cerebellopontine angle. A blue light endoscope for detection of 5-ALA fluorescence was introduced into our practice in 2014 and subsequently used for assistance with tumor resection in 24 cases (46.2%) (intraaxial: n = 22, extraaxial: n = 2). Beyond the use of the surgical microscope as the primary visualization source, the blue light endoscope was used to directly perform additional tumor resection in 19/21 cases as a result of improved fluorescence detection as compared to the surgical microscope. No complications were associated with the use of the endoscope or with additional resection performed under white or blue light visualization.

CONCLUSIONS Endoscopic assistance to visualize intracranial tumors had previously been limited to white light, assisting mostly in the visualization of extraaxial tumors confined to intraventricular and cisternal compartments. Blue light– equipped endoscopes provide improved versatility and visualization of 5-ALA fluorescing tissue beyond the capability of the surgical microscope, thereby expanding its use into the realm of intraaxial tumor resections.

The benefits of automated CSF drainage in normal pressure hydrocephalus

Acta Neurochirurgica (2023) 165:1505–1509

The commonly used cerebrospinal fluid (CSF) drainage system remains the manual drip-chamber drain. The LiquoGuard (Möller Medical GmbH, Germany) is an automated CSF management device with dual functionality, measuring intracranial pressure and automatic pressure- or volume-led CSF drainage. There is limited research for comparison of devices, particularly in the neurosurgical field, where it has potential to reshape care.

Objective This study aims to compare manual drip-chamber drain versus LiquoGuard system, by assessing accuracy of drainage, associated morbidity and impact on length of stay.

Method Inclusion criteria consisted of suspected normal pressure hydrocephalus (NPH) patients undergoing extended lumbar drainage. Patients were divided into manual drain group versus automated group.

Results Data was analysed from 42 patients: 31 in the manual group versus 11 in the LiquoGuard group. Volumetric overdrainage was seen in 90.3% (n = 28) versus 0% (p < 0.05), and under-drainage in 38.7% (n = 12) versus 0% (p < 0.05), in the manual and automatic group, respectively. Symptoms of over-drainage were noted in 54.8% (n = 17) of the manual group, all of which had episodes of volumetric over-drainage, versus 18.2% (n = 2) in automated group, of which neither had actual over-drainage (p < 0.05). Higher over-drainage symptoms of manual drain is likely due to increased fluctuation of CSF drainage, instead of smooth CSF drainage seen with LiquoGuard system. An increased length of stay was seen in 38.7% (n = 12) versus 9% (n = 1) (p < 0.05) in the manual and LiquoGuard group, respectively.

Conclusion The LiquoGuard device is a more superior way of CSF drainage in suspected NPH patients, with reduced morbidity and length of stay.

The value of ventricular measurements in the prediction of shunt dependency after aneurysmal subarachnoid hemorrhage

Acta Neurochirurgica (2023) 165:1545–1555

Chronic hydrocephalus requiring shunt placement is a common complication of aneurysmal subarachnoid hemorrhage (SAH). Different risk factors and prediction scores for post-SAH shunt dependency have been evaluated so far. We analyzed the value of ventricle measurements for prediction of the need for shunt placement in SAH patients.

Methods Eligible SAH cases treated between 01/2003 and 06/2016 were included. Initial computed tomography scans were reviewed to measure ventricle indices (bifrontal, bicaudate, Evans’, ventricular, Huckman’s, and third ventricle ratio). Previously introduced CHESS and SDASH scores for shunt dependency were calculated. Receiver operating characteristic analyses were performed for diagnostic accuracy of the ventricle indices and to identify the clinically relevant cut-offs.

Results Shunt placement followed in 221 (36.5%) of 606 patients. In univariate analyses, all ventricular indices were associated with shunting (all: p<0.0001). The area under the curve (AUC) ranged between 0.622 and 0.662. In multivariate analyses, only Huckman’s index was associated with shunt dependency (cut-off at ≥6.0cm, p<0.0001) independent of the CHESS score as baseline prediction model. A combined score (0–10 points) containing the CHESS score components (0–8 points) and Huckman’s index (+2 points) showed better diagnostic accuracy (AUC=0.751) than the CHESS (AUC=0.713) and SDASH (AUC=0.693) scores and the highest overall model quality (0.71 vs. 0.65 and 0.67), respectively.

Conclusions Ventricle measurements are feasible for early prediction of shunt placement after SAH. The combined prediction model containing the CHESS score and Huckman’s index showed remarkable diagnostic accuracy regarding identification of SAH individuals requiring shunt placement. External validation of the presented combined CHESS-Huckman score is mandatory.

Internal Ventricular Cerebrospinal Fluid Shunt for Adult Hydrocephalus: A Systematic Review and Meta-Analysis of the Infection Rate

Hydrocephalus is a common neurological condition that usually requires internal ventricular cerebrospinal fluid shunt (IVCSFS). The reported infection rate (IR) varies greatly from below 1% up to over 50%, but no meta-analysis to assess the overall IR has ever been performed.

OBJECTIVE: To determine the IVCSFS overall IR in the adult population and search for associated factors.

METHODS: Six databases were searched from January 1990 to July 2022. Only original articles reporting on adult IVCSFS IR were included. Random-effects meta-analysis with generalized linear mixed model method and logit transformation was used to assess the overall IR. RESULTS: Of 1703 identified articles, 44 were selected, reporting on 57259 patients who had IVCSFS implantation and 2546 infections. The pooled IR value and its 95% CI were 4.75%, 95% CI (3.8 to 5.92). Ninety-five percent prediction interval ranged from 1.19% to 17.1%. The patients who had IVCSFS after intracranial hemorrhage showed a higher IR (7.65%, 95% CI [5.82 to 10], P-value = .002). A meta-regression by year of publication found a decreasing IR (À0.031, 95% CI [À0.06 to 0.003], P-value = .032) over the past 32 years.

CONCLUSION: IVCSF is a procedure that every neurosurgeon should be well trained to perform. However, the complication rate remains high, with an estimated overall IR of 4.75%. The IR is especially elevated for hydrocephalic patients who require IVCSFS after intracranial hemorrhage. However, decades of surgical advances may have succeeded in reducing IR over the past 32 years.

Neurosurgery 92:894–904, 2023

Placebo-Controlled Effectiveness of Idiopathic Normal Pressure Hydrocephalus Shunting

Neurosurgery 92:481–489, 2023

Multiple prospective nonrandomized studies have shown 60% to 70% of patients with idiopathic normal pressure hydrocephalus (iNPH) improve with shunt surgery, but multicenter placebo-controlled trial data are necessary to determine its effectiveness.

OBJECTIVE: To evaluate the effectiveness of cerebrospinal fluid shunting in iNPH through comparison of open vs placebo shunting groups at 4 months using a pilot study.

METHODS: Patients were randomized to a Codman Certas Plus valve (Integra LifeSciences) set at 4 (open shunt group) or 8 (“virtual off”; placebo group). Patients and assessors were blinded to treatment group. The primary outcome measure was 10-m gait velocity. Secondary outcome measures included functional scales for bladder control, activities of daily living, depression, and quality of life. Immediately after 4-month evaluation, all shunts were adjusted in a blinded fashion to an active setting and followed to 12months after shunting.

RESULTS: A total of 18 patients were randomized. At the 4-month evaluation, gait velocity increased by 0.28 ± 0.28m/s in the open shunt group vs 0.04 ± 0.17m/s in the placebo group. The estimated treatment difference was 0.22 m/s ([P = .071], 95% CI 0.02 to 0.46). Overactive Bladder Short Form symptom bother questionnaire significantly improved in open shunt vs placebo (P = .007). The 4-month treatment delay did not reduce the subsequent response to active shunting, nor did it increase the adverse advents rate at 12 months.

CONCLUSION: This multicenter, randomized pilot study demonstrates the effectiveness, safety, and feasibility of a placebo-controlled trial in iNPH, and found a trend suggesting gait velocity improves more in the open shunt group than in the placebo group.

First Experience With Postoperative Transcranial Ultrasound Through Sonolucent Burr Hole Covers in Adult Hydrocephalus Patients

Neurosurgery 92:382–390, 2023

Managing patients with hydrocephalus and cerebrospinal fluid (CSF) disorders requires repeated head imaging. In adults, it is typically computed tomography (CT) or less commonly magnetic resonance imaging (MRI). However, CT poses cumulative radiation risks and MRI is costly. Ultrasound is a radiation-free, relatively inexpensive, and optionally point-of-care alternative, but is prohibited by very limited windows through an intact skull.

OBJECTIVE: To describe our initial experience with transcutaneous transcranial ultrasound through sonolucent burr hole covers in postoperative hydrocephalus and CSF disorder patients.

METHODS: Using cohort study design, infection and revision rates were compared between patients who underwent sonolucent burr hole cover placement during new ventriculoperitoneal shunt placement and endoscopic third ventriculostomy over the 1-year study time period and controls from the period 1 year before. Postoperatively, trans-burr hole ultrasound was performed in the clinic, at bedside inpatient, and in the radiology suite to assess ventricular anatomy.

RESULTS: Thirty-seven patients with sonolucent burr hole cover were compared with 57 historical control patients. There was no statistically significant difference in infection rates between the sonolucent burr hole cover group (1/37, 2.7%) and the control group (0/57, P = .394). Revision rates were 13.5% vs 15.8% (P = 1.000), but no revisions were related to the burr hole or cranial hardware.

CONCLUSION: Trans-burr hole ultrasound is feasible for gross evaluation of ventricular caliber postoperatively in patients with sonolucent burr hole covers. There was no increase in infection rate or revision rate. This imaging technique may serve as an alternative to CT and MRI in the management of select patients with hydrocephalus and CSF disorders.

Vascular risk profiles for predicting outcome and long-term mortality in patients with idiopathic normal pressure hydrocephalus: comparison of clinical decision support tools

J Neurosurg 138:476–482, 2023

Vascular risk factors (VRFs) may act synergistically, and clinical decision support tools (CDSTs) have been developed that present vascular risk as a summarized score. Because VRFs are a major issue in patients with idiopathic normal pressure hydrocephalus (INPH), a CDST may be useful in the diagnostic workup. The objective was to compare 4 CDSTs to determine which one most accurately predicts short-term outcome and 10-year mortality after CSF shunt surgery in INPH patients.

METHODS One-hundred forty INPH patients who underwent CSF shunt surgery were included. For each patient, 4 CDST scores (Systematic Coronary Risk Evaluation–Older Persons [SCORE-OP], Framingham Risk Score [FRS], Revised Framingham Stroke Risk Profile, and Kiefer’s Comorbidity Index [KCI]) were estimated. Short-term outcome (3 months after CSF shunt surgery) was defined on the basis of improvements in gait, Mini-Mental State Examination score, and modified Rankin Scale score. The 10-year mortality rate after surgery was noted. The CDSTs were compared by using Cox regression analysis, receiver operating characteristic curve analysis, and the chi-square test.

RESULTS For 3 CDSTs, increased score was associated with increased risk of 10-year mortality. A 1-point increase in the FRS indicated a 2% higher risk of death within 10 years (HR 1.02, 95% CI 1.003–1.035, p = 0.021); SCORE-OP, 5% (HR 1.05, 95% CI 1.019–1.087, p = 0.002); and KCI, 12% (HR 1.12, 95% CI 1.03–1.219, p = 0.008). FRS predicted short-term outcome of surgery (p = 0.024). When the cutoff value was set to 32.5%, the positive predictive value was 80% and the negative predictive value was 48% (p = 0.012).

CONCLUSIONS The authors recommend using FRS to predict short-term outcome and 10-year risk of mortality in INPH patients. The study indicated that extensive treatment of the risk factors of INPH may decrease risk of mortality.

The positive impact of cisternostomy with cisternal drainage on delayed hydrocephalus after aneurysmal subarachnoid hemorrhage

Acta Neurochirurgica (2023) 165:187–195

Hydrocephalus is one of the major complications of aneurysmal subarachnoid haemorrhage (aSAH). In the acute setting, an external ventricular drain (EVD) is used for early management. A cisternal drain (CD) coupled with the micro-surgical opening of basal cisterns can be an alternative when the aneurysm is clipped. Chronic hydrocephalus after aSAH is managed with ventriculo-peritoneal (VP) shunt, a procedure associated with a wide range of complications. The aim of this study is to analyse the impact of microsurgical opening of basal cisterns coupled with CD on the incidence of VP shunt, compared to patients treated with EVD.

Methods The authors conducted a retrospective review of 89 consecutive cases of patients with aSAH treated surgically and endovascularly with either EVD or CD between January 2009 and September 2021. Patients were stratified into two groups: Group 1 included patients with EVD, Group 2 included patients with CD. Subgroup analysis with only patients treated surgically was also performed. We compared their baseline characteristics, clinical outcomes and shunting rates.

Results There were no statistically significant differences between the two groups in terms of epidemiological characteristics, WFNS score, Fisher scale, presence of intraventricular hemorrhage (IVH), acute hydrocephalus, postoperative meningitis or of clinical outcomes at last follow-up. Cisternostomy with CD (Group 2) was associated with a statistically significant reduction in VP-shunt compared with the use of an EVD (Group 1) (9.09% vs 53.78%; p < 0.001). This finding was confirmed in our subgroup analysis, as among patients with a surgical clipping, the rate of VP shunt was 43.7% for the EVD group and 9.5% for the CD group (p = 0.02).

Conclusions Cisternostomy with CD may reduce the rate of shunt-dependent hydrocephalus. Cisternostomy allows the removal of subarachnoid blood, thereby reducing arachnoid inflammation and fibrosis. CD may enhance this effect, thus resulting in lower rates of chronic hydrocephalus.

Keywords Cisternostomy · Cisternal drain · External ventricular drain · Aneurysmal subarachnoid haemorrhage · Hydrocephalus · Ventriculo-peritoneal shunt

Failure of Internal Cerebrospinal Fluid Shunt: A Systematic Review and Meta-Analysis of the Overall Prevalence in Adults

World Neurosurg. (2023) 169:20-30

Reported rates of failures of internal cerebrospinal fluid shunt (ICSFS) vary greatly from less than 5% to more than 50% and no meta-analysis to assess the overall prevalence has been performed. We estimated the failure rate after ICSFS insertion and searched for associated factors.

METHODS: Six databases were searched from January 1990 to February 2022. Only original articles reporting the rate of adult shunt failure were included. Random-effects meta-analysis with a generalized linear mixed model method and logit transformation was used to compute the overall failure prevalence. Subgroup analysis and meta-regression were implemented to search for associated factors.

RESULTS: Of 1763 identified articles, 46 were selected, comprising 70,859 ICSFS implantations and 13,603 shunt failures, suggesting an accumulated incidence of 19.2%. However, the calculated pooled prevalence value and its 95% confidence interval (CI) were 22.7% (95% CI, 19.8e5.8). The CI of the different estimates did not overlap, indicating a strong heterogeneity confirmed by a high I 2 of 97.5% (95% CI, 97.1e97.8; P < 0.001; s 2 [ 0.3). Ninety-five percent prediction interval of shunt failure prevalence ranged from 8.75% to 47.36%. A meta-regression of prevalence of publication found a barely significant decreasing failure rate of about 2% per year (e2.11; 95% CI, e4.02 to e0.2; P [ 0.031).

CONCLUSIONS: Despite being a simple neurosurgical procedure, ICSFS insertion has one of the highest risk of complications, with failure prevalence involving more than 1 patient of 5. Nonetheless, all efforts to lower this high level of shunt failure seem to be effective.