Efficacy and safety of programmable shunt valves for hydrocephalus: A meta-analysis

Influence of distal insertion technique, valve selection, and patient demographics on shunt survival in ventriculoperitoneal shunt insertion: A retrospective analysis of an Australian case series

BACKGROUND

Ventriculoperitoneal (VP) shunt insertion is a means of diverting cerebrospinal fluid (CSF) for management of hydrocephalus. Revision rates, operating time, and length of stay (LOS) following laparoscopic insertion of the distal catheter have been mixed. There are limited data on the role of adhesiolysis during VP shunt insertion. Valve characteristics have also been shown to influence patient outcomes. There is a paucity of Australian data reporting on the effect of these variables on shunt outcomes. We aimed to study patient demographics, indications, and surgical and instrument variables in the Australian context.

METHODS

We performed a retrospective, multi-surgeon, single-centre analysis of VP shunts inserted in adults via an open or laparoscopic technique. Data on patient demographics and surgery characteristics were collected from the hospital medical records and the Australasian Shunt Registry. The primary outcome was shunt revision rate and secondary outcomes were postoperative complications, operating time and LOS, and shunt survivability.

RESULTS

Fifty-six participants were eligible for analysis. The overall revision rate was 14.3 %, which was lower than the national average. The distal catheter revision rate was 0 %. Laparoscopic insertion of the distal catheter was shown to significantly reduce operating time (70.4 min in the open group and 50.7 min in the laparoscopic group, p < 0.001). This was demonstrated across different aetiologies, and when controlling for age and valve-type (p < 0.05). The revision rate of non-programmable was higher than programmable valves (42.9 % versus 2.9 %, respectively). There were no differences between previous abdominal surgery, LOS, complication, or revision rate between open and laparoscopic insertion. VP shunt survivability was greater in the laparoscopic group (90-day shunt survival of 96.7 % and 92 % in the laparoscopy and open groups, respectively; p > 0.05). We did not find any significant difference in operating time or length of stay for age, sex, or previous abdominal surgery, even when accounting for surgical technique. Indication and shunt survivability varied widely between age groups. The use of laparoscopic insertion increased over time, though surgeons did not crossover techniques.

CONCLUSIONS

The overall distal revision rate of VP shunts is low. Laparoscopic insertion of the distal catheter reduces operating time and may improve shunt survivability. Larger studies are needed to confirm differences in shunt survivability in open versus laparoscopic distal catheter insertion, between age groups, clinical indications, and valve type on patient outcomes.

Ventricular CSF proteomic profiles and predictors of surgical treatment outcome in chronic hydrocephalus

BACKGROUND

By applying an unbiased proteomic approach, we aimed to search for cerebrospinal fluid (CSF) protein biomarkers distinguishing between obstructive and communicating hydrocephalus in order to improve appropriate surgical selection for endoscopic third ventriculostomy vs. shunt implants. Our second study purpose was to look for potential CSF biomarkers distinguishing between patients with adult chronic hydrocephalus benefitting from surgery (responders) vs. those who did not (non-responders).

METHODS

Ventricular CSF samples were collected from 62 patients with communicating hydrocephalus and 28 patients with obstructive hydrocephalus. CSF was collected in relation to the patients' surgical treatment. As a control group, CSF was collected from ten patients with unruptured aneurysm undergoing preventive surgery (vascular clipping).

RESULTS

Mass spectrometry-based proteomic analysis of the samples identified 1251 unique proteins. No proteins differed significantly between the communicating hydrocephalus group and the obstructive hydrocephalus group. Four proteins were found to be significantly less abundant in CSF from communicating hydrocephalus patients compared to control subjects. A PCA plot revealed similar proteomic CSF profiles of obstructive and communicating hydrocephalus and control samples. For obstructive hydrocephalus, ten proteins were found to predict responders from non-responders.

CONCLUSION

Here, we show that the proteomic profile of ventricular CSF from patients with hydrocephalus differs slightly from control subjects. Furthermore, we find ten predictors of response to surgical outcome (endoscopic third ventriculostomy or ventriculo-peritoneal shunt) in patients with obstructive hydrocephalus.

Long-term follow-up and comparison of programmable and non-programmable ventricular cerebrospinal fluid shunts among adult patients with different hydrocephalus etiologies: a retrospective cohort study

BACKGROUND

Programmable valve (PV) has been shown as a solution to the high revision rate in pediatric hydrocephalus patients, but it remains controversial among adults. This study is to compare the overall revision rate, revision cause, and revision-free survival between PV and non-programmable valve (NPV) in adult patients with different hydrocephalus etiologies.

METHOD

We reviewed the chart of all patients with hydrocephalus receiving index ventricular cerebrospinal fluid (CSF) shunt operations conducted at a single institution from January 2017 to December 2017. Patients included in the study were followed up for at least 5 years. Statistical tests including independent t-test, chi-square test, and Fisher's exact test were used for comparative analysis, and Kaplan-Meier curve using log-rank test was performed to compare the revision-free survival between the PV and NPV groups.

RESULTS

A total of 325 patients were included in the study, of which 181 patients were receiving PVs and 144 patients receiving NPV. There were 23 patients (12.8%) with PV and 22 patients (15.3%) with NPV receiving initial revision. No significant statistical difference in the initial revision rate was observed between the two groups (p = 0.52). No survival difference was found between the PV and NPV groups. However, better revision-free survival was noted in the PV group among idiopathic normal pressure hydrocephalus (iNPH) (p = 0.0274) and post-traumatic hydrocephalus (p = 0.017).

CONCLUSIONS

The combination of the different etiologies of hydrocephalus and the features of PV and NPV results in different outcomes-revision rate and revision-free survival. PV use might be superior to NPV in iNPH and post-traumatic hydrocephalus patients. Further studies are needed to clarify the indications of PV use in adult hydrocephalus patients.

Programmable Versus Differential Pressure Ventriculoperitoneal Shunts for Pediatric Hydrocephalus: A 20-Year Single-Center Experience From Saudi Arabia

Background Shunt malfunction is the most common complication after ventriculoperitoneal shunt (VPS) insertion for pediatric hydrocephalus. The incidence of shunt malfunction and the need for VPS revision may be related to the type of valve used in the shunt. Therefore, we aimed to compare the outcome of VPS in the pediatric age group stratified by differential pressure valves (DPV) and programmable shunt valves (PSV). Materials and methods This ethics-approved retrospective study was conducted at a tertiary care hospital in Saudi Arabia. We included 175 children with congenital hydrocephalus who underwent a shunt insertion or revision between 2003 and 2018 and followed them up to December 2022. The VPS complication and revision rates were compared with the patient's demographics and shunt valve types. The Kaplan-Meier method, log-rank test, and univariate and multivariate Cox proportional hazards regression were used to analyze several variables and subsequent shunt revisions. Results Females represented 52% of the study participants, and the mean age of the patients was 21.7 ± 38.4 months. The main indication for VPS was congenital hydrocephalus due to aqueductal stenosis (40%). The differential shunt valve was used in 78.9% and the PSV in 21.1% of the patients. Surgical complications occurred in 33.7% of the patients. Shunt malfunction and infection occurred in 16% and 11.4% of the patients, respectively. The VPS revision rate was significantly lower when PSV was used (odds ratio = 0.39, P < 0.05). Conclusion Overall, one-third of the studied pediatric cohort required shunt revision at some point during the 15-year follow-up. However, children with PSV had fewer revision rate-related complications compared to children with DPV during the first five years of follow-up.

Fixed versus Adjustable differential pressure valves in case of idiopathic normal pressure hydrocephalus treated with ventriculoperitoneal shunt. A systematic review and meta-analysis of proportion

INTRODUCTION

Idiopathic normal pressure hydrocephalus is a common cause of communicating hydrocephalus in adult age, presenting with classic Hakim-Adam's triad. Ventriculoperitoneal shunting is the treatment of choice in these cases. The main objective of this study is to compare the complication rate of Adjustable differential pressure valves with fixed differential pressure valves in these cases.

LITERATURE SEARCH

We systematically searched PubMed/Medline, Embase, LILACS, and ClinicalTrials.gov from their date of inception to 30th Jan 2023. We included observational studies, Randomized Controlled Trials (RCTs), and comparative and noncomparative studies in the search. The literature search resulted in 1394 studies, and only 22 studies were eligible to be included in the meta-analysis. We performed the meta-analysis of proportion to compare incidence rates by performing a Freeman-turkey double arcsine transformation.

RESULTS

The summary of the proportions of the incidence rate of complications was less for Adjustable Differential Pressure Valves (ADPV) as compared to Fixed Differential Pressure Valves (FDVP) but the confidence intervals overlapped. The summary proportion of surgical revision of shunt in the case of ADPV was 0.081 (95% CI (0.047, 0.115)), and in the case of FDPV was 0.173 (95% CI (0.047, 0.299)). Similarly, the summary proportion of subdural fluid collection in the case of ADPV was 0.090 (0.058, 0.122), and in the case of FDPV was 0.204 (0.132, 0.277). The incidence of complication was low in population implanted with DPV along with gravitational or anti-siphon unit (GASU).

CONCLUSION

Complication rates in the case of ADPV plus GASU were the lowest. Though the summary proportion of complication rate in the case of ADPV was low as compared to FDPV, the statistical significance of this difference is doubted due to overlapping confidence intervals.

Determination of Programmable Shunt Setting Using CT: Feasibility Study

BACKGROUND

Programmable shunts can be adjusted to optimize CSF diversion in patients with hydrocephalus without the need for re-operation. Currently, all shunts incorporate radiopaque markers so that their setting can be determined on skull X-ray images. The purpose of this study was to evaluate whether the shunt setting could also be determined ex vivo and in vivo using the data from a standard head CT scan since one is nearly always obtained when patients with VP shunts present with new symptoms that could be due to shunt malfunction.  Materials and Methods: Four commonly used programmable shunts were attached to a dried skull and scanned using a variety of CT techniques. The shunts imaged were the CertasTM Plus (Codman, Raynham, Massachusetts), Polaris® (Sophysa, Orsay, France), proGAV 2.0® (Braun, Bethlehem, Pennsylvania), and Hakim® (Codman, Raynham, Massachusetts). Each shunt was scanned at two different valve settings using multiple CT techniques: CTDIvol 75, 140kVp, 330mAs, CTDIvol60, 120kVp 390mAs, CTDIvol40, 80kVp with 430mAs, 140kVp with 215mAs. Image reconstruction with and without CT metal suppression software was used for all scans, and the data was reconstructed into volume-rendered images. We enlisted ten observers to review the volume-rendered images only. After a short set of training slides viewed by all observers, they were asked to predict the shunt setting for each valve along with their level of confidence. One clinical case of a patient with a programmable valve was evaluated on a CT scan.

RESULTS

 Using the volume-rendered images only, the two shunt settings of the Polaris shunt were correctly predicted by all the observers and in nine of 10 settings for the CertasTM Plus valve. For the Hakim® shunt and the proGAV 2.0® shunt, setting prediction accuracy was 0% and 10%, respectively. In one clinical case, the programmable valve setting could be determined from the CT scan data.

CONCLUSION

 The valve setting of at least two currently available programmable shunts can be determined using volume-rendered images generated from CT data. Reconstructions using metal suppression software were rated as superior and may be necessary for some valve designs.

In vitro testing of explanted shunt valves in hydrocephalic patients with suspected valve malfunction

Diagnosis of symptomatic valve malfunction in hydrocephalic patients treated with VP-Shunt (VPS) might be difficult. Clinical symptoms such as headache or nausea are nonspecific, hence cerebrospinal fluid (CSF) over- or underdrainage can only be suspected but not proven. Knowledge concerning valve malfunction is still limited. We aim to provide data on the flow characteristics of explanted shunt valves in patients with suspected valve malfunction. An in vitro shunt laboratory setup was used to analyze the explanted valves under conditions similar to those in an implanted VPS. The differential pressure (DP) of the valve was adjusted stepwise to 20, 10, 6, and 4 cmH₂O. The flow rate of the explanted and the regular flow rate of an identical reference valve were evaluated at the respective DPs. Twelve valves of different types (Codman CertasPlus valve n = 3, Miethke Shuntassistant valve n = 4, Codman Hakim programmable valve n = 3, DP component of Miethke proGAV 2.0 valve n = 2) from eight hydrocephalic patients (four male), in whom valve malfunction was assumed between 2016 and 2017, were replaced with a new valve. Four patients suffered from idiopathic normal pressure (iNPH), three patients from malresorptive and one patient from obstructive hydrocephalus. Post-hoc analysis revealed a significant difference (p < 0.001) of the flow rate between each explanted valve and their corresponding reference valve, at each DP. In all patients, significant alterations of flow rates were demonstrated, verifying a valve malfunction, which could not be objectified by the diagnostic tools used in the clinical routine. In cases with obscure clinical VPS insufficiency, valve deficiency should be considered.

Guidelines for Management of Idiopathic Normal Pressure Hydrocephalus (Third Edition): Endorsed by the Japanese Society of Normal Pressure Hydrocephalus

Among the various disorders that manifest with gait disturbance, cognitive impairment, and urinary incontinence in the elderly population, idiopathic normal pressure hydrocephalus (iNPH) is becoming of great importance. The first edition of these guidelines for management of iNPH was published in 2004, and the second edition in 2012, to provide a series of timely, evidence-based recommendations related to iNPH. Since the last edition, clinical awareness of iNPH has risen dramatically, and clinical and basic research efforts on iNPH have increased significantly. This third edition of the guidelines was made to share these ideas with the international community and to promote international research on iNPH. The revision of the guidelines was undertaken by a multidisciplinary expert working group of the Japanese Society of Normal Pressure Hydrocephalus in conjunction with the Japanese Ministry of Health, Labour and Welfare research project. This revision proposes a new classification for NPH. The category of iNPH is clearly distinguished from NPH with congenital/developmental and acquired etiologies. Additionally, the essential role of disproportionately enlarged subarachnoid-space hydrocephalus (DESH) in the imaging diagnosis and decision for further management of iNPH is discussed in this edition. We created an algorithm for diagnosis and decision for shunt management. Diagnosis by biomarkers that distinguish prognosis has been also initiated. Therefore, diagnosis and treatment of iNPH have entered a new phase. We hope that this third edition of the guidelines will help patients, their families, and healthcare professionals involved in treating iNPH.

Ventriculo-peritoneal shunting devices for hydrocephalus

BACKGROUND

Hydrocephalus is a common neurological disorder, caused by a progressive accumulation of cerebrospinal fluid (CSF) within the intracranial space that can lead to increased intracranial pressure, enlargement of the ventricles (ventriculomegaly) and, consequently, to brain damage. Ventriculo-peritoneal shunt systems are the mainstay therapy for this condition, however there are different types of shunt systems.

OBJECTIVES

To compare the effectiveness and adverse effects of conventional and complex shunt devices for CSF diversion in people with hydrocephalus.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (2020 Issue 2); Ovid MEDLINE (1946 to February 2020); Embase (Elsevier) (1974 to February 2020); Latin American and Caribbean Health Science Information Database (LILACS) (1980 to February 2020); ClinicalTrials.gov; and World Health Organization International Clinical Trials Registry Platform.

SELECTION CRITERIA

We selected randomised controlled trials or quasi-randomised trials of different types of ventriculo-peritoneal shunting devices for people with hydrocephalus. Primary outcomes included: treatment failure, adverse events and mortality.

DATA COLLECTION AND ANALYSIS

Two review authors screened studies for selection, assessed risk of bias and extracted data. Due to the scarcity of data, we performed a Synthesis Without Meta-analysis (SWiM) incorporating GRADE for the quality of the evidence.

MAIN RESULTS

We included six studies with 962 participants assessing the effects of standard valves compared to anti-syphon valves, other types of standard valves, self-adjusting CSF flow-regulating valves and external differential programmable pressure valves. All included studies started in a hospital setting and offered ambulatory follow-up. Most studies were conducted in infants or children with hydrocephalus from diverse causes. The certainty of the evidence for most comparisons was low to very low. 1. Standard valve versus anti-syphon valve Three studies with 296 randomised participants were included under this comparison. We are uncertain about the incidence of treatment failure in participants with standard valve and anti-syphon valves (very low certainty of the evidence). The incidence of adverse events may be similar in those with standard valves (range 0 to 1.9%) and anti-syphon valves (range 0 to 2.9%) (low certainty of the evidence). Mortality may be similar in those with standard valves (0%) and anti-syphon valves (0.9%) (RD 0.01%, 95% CI -0.02% to 0.03%, low certainty of the evidence). Ventricular size and head circumference may be similar in those with standard valves and anti-syphon valves (low certainty of the evidence). None of the included studies reported the quality of life of participants. 2. Comparison between different types of standard valves Two studies with 174 randomised participants were included under this comparison. We are uncertain about the incidence of treatment failure in participants with different types of standard valves (early postoperative period: RR 0.41, 95% CI 0.13 to 1.27; at 12 months follow-up: RR 1.17, 95% CI 0.72 to 1.92, very low certainty of the evidence). None of the included studies reported adverse events beyond those included under "treatment failure". We are uncertain about the effects of different types of standard valves on mortality (range 2% to 17%, very low certainty of the evidence). The included studies did not report the effects of these interventions on quality of life, ventricular size reduction or head circumference. 3. Standard valve versus self-adjusting CSF flow-regulating valve One study with 229 randomised participants addressed this comparison. The incidence of treatment failure may be similar in those with standard valves (42.98%) and self-adjusting CSF flow-regulating valves (39.13%) (low certainty of the evidence). The incidence of adverse events may be similar in those with standard valves (range 0 to 1.9%) and those with self-adjusting CSF flow-regulating valves (range 0 to 7.2%) (low certainty of the evidence). The included study reported no deaths in either group in the postoperative period. Beyond the early postoperative period, the authors stated that nine patients died (no disaggregated data by each type of intervention was available, low certainty of the evidence). The included studies did not report the effects of these interventions on quality of life, ventricular size reduction or head circumference. 4. External differential programmable pressure valve versus non-programmable valve One study with 377 randomised participants addressed this comparison. The incidence of treatment failure may be similar in those with programmable valves (52%) and non-programmable valves (52%)  (RR 1.02, 95% CI 0.84 to 1.24, low certainty of the evidence). The incidence of adverse events may be similar in those with programmable valves (6.19%) and non-programmable valves (6.01%) (RR 0.97, 95% CI 0.44 to 2.15, low certainty of the evidence). The included study did not report the effect of these interventions on mortality, quality of life or head circumference. Ventricular size reduction may be similar in those with programmable valves and non-programmable valves (low certainty of the evidence).

AUTHORS' CONCLUSIONS

Standard shunt valves for hydrocephalus compared to anti-syphon or self-adjusting CSF flow-regulating valves may cause little to no difference on the main outcomes of this review, however we are very uncertain due to the low to very low certainty of evidence. Similarly, different types of standard valves and external differential programmable pressure valves versus non-programmable valves may be associated with similar outcomes. Nevertheless, this review did not include valves with the latest technology, for which we need high-quality randomised controlled trials focusing on patient-important outcomes including costs.

Comparative durability and costs analysis of ventricular shunts

OBJECTIVE

Ventricular shunt (VS) durability has been well studied in the pediatric population and in patients with normal pressure hydrocephalus; however, further evaluation in a more heterogeneous adult population is needed. This study aims to evaluate the effect of diagnosis and valve type-fixed versus programmable-on shunt durability and cost for placement of shunts in adult patients.

METHODS

The authors retrospectively reviewed the medical records of all patients who underwent implantation of a VS for hydrocephalus at their institution over a 3-year period between August 2013 and October 2016 with a minimum postoperative follow-up of 6 months. The primary outcome was shunt revision, which was defined as reoperation for any indication after the initial procedure. Supply costs, shunt durability, and hydrocephalus etiologies were compared between fixed and programmable valves.

RESULTS

A total of 417 patients underwent shunt placement during the index time frame, consisting of 62 fixed shunts (15%) and 355 programmable shunts (85%). The mean follow-up was 30 ± 12 (SD) months. The shunt revision rate was 22% for programmable pressure valves and 21% for fixed pressure valves (HR 1.1 [95% CI 0.6-1.8]). Shunt complications, such as valve failure, infection, and overdrainage, occurred with similar frequency across valve types. Kaplan-Meier survival curve analysis showed no difference in durability between fixed (mean 39 months) and programmable (mean 40 months) shunts (p = 0.980, log-rank test). The median shunt supply cost per index case and accounting for subsequent revisions was $3438 (interquartile range $2938-$3876) and $1504 (interquartile range $753-$1584) for programmable and fixed shunts, respectively (p < 0.001, Wilcoxon rank-sum test). Of all hydrocephalus etiologies, pseudotumor cerebri (HR 1.9 [95% CI 1.2-3.1]) and previous shunt malfunction (HR 1.8 [95% CI 1.2-2.7]) were found to significantly increase the risk of shunt revision. Within each diagnosis, there were no significant differences in revision rates between shunts with a fixed valve and shunts with a programmable valve.

CONCLUSIONS

Long-term shunt revision rates are similar for fixed and programmable shunt pressure valves in adult patients. Hydrocephalus etiology may play a significant role in predicting shunt revision, although programmable valves incur higher supply costs regardless of initial diagnosis. Utilization of fixed pressure valves versus programmable pressure valves may reduce supply costs while maintaining similar revision rates. Given the importance of developing cost-effective management protocols, this study highlights the critical need for large-scale prospective observational studies and randomized clinical trials of ventricular shunt valve revisions and additional patient-centered outcomes.

Comparison of Complication and Revision Rates After Frontal Versus Parietal Approach for Ventricular Shunt Placement in Idiopathic Normal Pressure Hydrocephalus

BACKGROUND

Ventricular shunts are most commonly placed via a frontal or parietal approach. However, there is a paucity of data comparing complication and revision rates associated with these approaches in the idiopathic normal pressure hydrocephalus (iNPH) population.

METHODS

Patients with iNPH treated with ventricular shunting between 2001 and 2017 at our institution were included for analysis. Patient characteristics, catheter accuracy, and incidence of revision were determined from the medical record. Catheter accuracy was determined using axial computed tomography imaging and classified as grade 1, 2, or 3 based on location of the catheter tip.

RESULTS

There were 348 patients included for analysis with 266 (76.4%) and 82 (23.6%) receiving a frontal versus parietal shunt, respectively. Patients undergoing the parietal approach were more likely to receive a programmable valve (37.8% vs. 25.2%; P = 0.026). Neuronavigation was used more frequently for patients undergoing the parietal approach (26.8% vs. 4.1%; P < 0.001); however, a minority of cases used neuronavigation in general (9.5%). There was no difference in catheter accuracy between the 2 approaches and no difference in catheter accuracy with the use of neuronavigation. The overall revision rate was 21.0%, and there were no differences in the incidence of revisions between the frontal and parietal approaches (21.8% vs. 18.3%, respectively; P = 0.495). There were no differences in revision subtypes between the approaches.

CONCLUSIONS

These results suggest that the type of approach for shunting may not have a significant impact on complication and revision rates in patients with iNPH, and either approach is a reasonable first-line option.

MRI Compatibility: Automatic Brain Shunt Valve Recognition using Feature Engineering and Deep Convolutional Neural Networks

The aim of this study is to evaluate whether we could develop a machine learning method to distinguish models of cerebrospinal fluid shunt valves (CSF-SVs) from their appearance in clinical X-rays. This is an essential component of an automatic MRI safety system based on X-ray imaging. To this end, a retrospective observational study using 416 skull X-rays from unique subjects retrieved from a clinical PACS system was performed. Each image included a CSF-SV representing the most common brands of programmable shunt valves currently used in US which were split into five different classes. We compared four machine learning pipelines: two based on engineered image features (Local Binary Patterns and Histogram of Oriented Gradients) and two based on features learned by a deep convolutional neural network architecture. Performance is evaluated using accuracy, precision, recall and f1-score. Confidence intervals are computed with non-parametric bootstrap procedures. Our best performing method identified the valve type correctly 96% [CI 94–98%] of the time (CI: confidence intervals, precision 0.96, recall 0.96, f1-score 0.96), tested using a stratified cross-validation approach to avoid chances of overfitting. The machine learning pipelines based on deep convolutional neural networks showed significantly better performance than the ones based on engineered image features (mean accuracy 95–96% vs. 56–64%). This study shows the feasibility of automatically distinguishing CSF-SVs using clinical X-rays and deep convolutional neural networks. This finding is the first step towards an automatic MRI safety system for implantable devices which could decrease the number of patients that experience denials or delays of their MRI examinations.