Exclusive use of fixed pressure valves for cerebrospinal fluid diversion in a modern adult cohort

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.

Ventricular Peritoneal Shunting Using Modified Keen’s Point Approach: Technical Report and Cases Series

Background: Ventricular peritoneal shunting (VPS) is a frequent procedure in neurosurgery, unfortunately still burdened with a significant rate of complications. The frontal Kocher’s point is the most frequently used landmark for ventricular puncture. Keen’s point (posterior parietal approach) seems to be a valid alternative. We report a newly described access to the lateral ventricle located in posterior temporal area and the results of a large series of adult patients. Methods: Retrospective analysis of a series of 188 cases of VPS performed with this approach. Results: Mean surgical time was 51.5 +/− 13.1 min (range 25–90 min). Twenty-one patients (11.2%) were subjected to revision surgery: eight cases (4.3%) for displacement or malfunction of ventricular catheter, eight cases (4.3%) for abdominal issues, three cases (1.6%) for hardware failure, and two cases (1.1%) for infection. Optimal catheter placement was reached in 90.1%. Conclusions: The modified Keen’s point approach seems to be safe, technically feasible, and reproducible, showing some potential advantages such as short surgical time, precision in ventricular catheter placement, and short tunneling tract. The need for surgical revision is similar to that reported in the literature, while the rate of catheter malpositioning and infections seems to be low; hemorrhages around catheter and seizures were not reported.

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.

Ventriculoperitoneal shunt complications in an adult population: A comparison of various shunt designs to prevent overdrainage

Background:

Overdrainage after cerebrospinal fluid diversion remains a significant morbidity. The hydrostatic, gravitational force in the upright position can aggravate this. Siphon control (SC) mechanisms, as well as programmable and flow regulating devices, were developed to counteract this. However, limited studies have evaluated their safety and efficacy. In this study, direct comparisons of the complication rates between siphon control (SC) and non-SC (NSC), fixed versus programmable, and flow- versus pressure regulating valves are undertaken.

Methods:

A retrospective chart review was performed over all shunt implantations from January 2011 to December 2016 within the Houston Methodist Hospital system. Complication rates within 6 months of the operative date, including infection, subdural hematoma, malfunction, and any other shunt-related complication, were analyzed via Fisher’s exact test, with P < 0.05 regarded as significant. Subgroup analyses based on diagnoses – normal pressure hydrocephalus (HCP), pseudotumor cerebri, or other HCP – were also performed.

Results:

The overall shunt-related complication rate in this study was 19%. Overall rates of infection, shunt failure, and readmission within 180 days were 3%, 11%, and 34%, respectively. No difference was seen between SC and NSC groups in any complication rate overall or on subgroup analyses. When comparing fixed versus programmable and flow- versus pressure-regulating valves, the latter in each analysis had significantly lower malfunction and total complication rates.

Conclusions:

Programmable and pressure regulating devices may lead to lower shunt malfunction and total complication rates. Proper patient selection should guide valve choice. Future prospective studies may further elucidate the difference in complication rates between these various shunt designs.

Clinical performance of fixed-pressure Sphera Duo® hydrocephalus shunt

INTRODUCTION

Cerebral hydrodynamics complications in shunted patients are due to the malfunction of the system. The objective of this retrospective, single-center, single-arm cohort study is to confirm the safety and performance of Sphera® Duo when used in adult patients suffering from hydrocephalus, pseudotumor cerebri or arachnoid cysts.

METHODS

Data were generated by reviewing 112 adult patient's charts, who were submitted to a ventriculoperitoneal shunt surgery and followed for one year after surgery.

RESULTS

The results show us that 76% of patients had their neurological symptoms improved and that the reoperation rate was 15% in the first year following surgery.

DISCUSSION

Sphera Duo® shunt system is an applicable shunt option in routine neurosurgical management of hydrocephalus by several causes. It has presented good results while mitigating effects of overdrainage. Overdrainage is especially important in adults with non-hypertensive hydrocephalus and can cause functional shunt failure, which causes subnormal ICP (particularly in the upright position) and is associated with characteristic neurological symptoms, such as postural headache and nausea.

CONCLUSION

Sphera Duo® shunt system is safe when used in adult patients suffering from hydrocephalus, pseudotumor cerebri or arachnoid cyst.

Application of the Preventable Shunt Revision Rate to an Adult Population

BACKGROUND

The preventable shunt revision rate (PSRR) was recently introduced in pediatric hydrocephalus as a quality metric for shunt surgery. We evaluated the PSRR in an adult hydrocephalus population.

METHODS

All ventricular shunt operations (January 1, 2013 to March 31, 2018) performed at a university-based teaching hospital were included. For any index surgery (de novo or revision) resulting in reoperation within 90 days, the index surgery details were collected, and a consensus decision was reached regarding whether the failure had been potentially avoidable. Preventable failure was defined as failure due to infection, malposition, disconnection, migration, or kinking. The 90-day shunt failure rate and PSRR were calculated. Bivariate analyses were performed to evaluate the individual effects of each independent variable on preventable shunt failure.

RESULTS

A total of 318 shunt operations had been performed in 245 patients. Most patients were women (62%), with a median age of 48.2 years (interquartile range, 31.2-63.2 years). Most had had ventriculoperitoneal shunts placed (86.5%), and just more than one half were new shunts (51.6%). A total of 53 cases (16.7%) in 42 patients experienced shunt failure within 90 days of the index operation. Of these, 27 failures (8.5% of the total cases; 51% of the failures) were considered potentially preventable. The most common reasons were infection (37%; n = 10) and malposition of the proximal and distal catheters (both 25.9%; n = 7). Age was the only statistically significant difference between the 2 groups, with the patients experiencing preventable shunt failure older than those without preventable shunt failure (51.4 vs. 37.1 years; P = 0.017).

CONCLUSIONS

The 90-day PSRR can be applied to an adult population and serve as a quality metric.