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  • Effect of Fixed-setting Versus Programmable Valve on Incidence of Shunt Revision after Ventricular Shunting for Normal Pressure Hydrocephalus

    Final Number:

    Lorenzo Rinaldo MD PhD; Giuseppe Lanzino MD; Benjamin D. Elder MD PhD

    Study Design:

    Subject Category:

    Meeting: Congress of Neurological Surgeons 2018 Annual Meeting

    Introduction: Shunt revision surgery is often necessary for patients with normal pressure hydrocephalus (NPH). We compared shunt revision rates between patients receiving a fixed-setting (FSV) versus programmable valve (PV).

    Methods: Patients with NPH treated with ventricular shunting between 2001 and 2017 were included for analysis. The incidence of shunt revision was determined from the electronic medical record, and the indication for revision was categorized as follows: proximal obstruction, distal obstruction, infection, overdrainage, or no obstruction with persistent symptoms. Risk factors for revision subtypes were identified using a Cox proportional hazards model.

    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), and all patients undergoing multiple revisions initially received a FSV. Patients with a PV were less likely to undergo revision due to distal obstruction (1.0% vs 6.8%; p = 0.030) and persistent symptoms without obstruction (2.0% vs 8.8%; p = 0.032). On multivariate analysis, increasing age (Unit RR 0.93, 95% CI 0.90-0.96; p = 0.001) and PVs (RR 0.18, 95% CI 0.01-0.90; p = 0.035) were associated with reduced risk of distal obstruction, and PVs were associated with reduced risk of revision due to persistent symptoms without obstruction (RR 0.26, 95% CI 0.04-0.91; p = 0.032). PVs were associated with more frequent shunt series during follow-up (4.1 vs 1.0 x-rays/follow-up year; p < 0.001), but not more frequent head CT scans (4.8 vs 3.9 CTs/follow-up year; p = 0.26).

    Conclusions: Our results suggest that programmable valves lead to reduced rates of shunt revision in patients with NPH. Despite the increased cost of PVs, they may be cost-effective.

    Patient Care: Our research provides evidence that use of programmable valves for patients with normal pressure hydrocephalus treated with ventricular shunting may reduce the rate of subsequent shunt revision surgery.

    Learning Objectives: By the conclusion of this session, participants should be able to: 1) identify shunt revision subtypes that are more common in patients with normal pressure hydrocephalus treated with a fixed setting valve.


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