Idiopathic Normal Pressure Hydrocephalus and Shunt Complications per Valve Type: A Meta-Analysis of Proportions

Idiopathic normal pressure hydrocephalus is classically recognized by the triad of gait disturbance, cognitive dysfunction, and urinary incontinence. Since ventricular shunting may be affected by valve type, we conducted a meta-analysis to assess the relationship between valve characteristics and outcomes.

English language studies that reported valve types, outcomes, and associated complications were included. Data were extracted and analyzed using R, version 4.3.2.

Thirteen studies were included. With gravitational valves, meta-analysis yielded 0.04 [0.02, 0.07] for subdural effusions (SDEs), 0.00 [0.00, 0.00] for surgical SDEs, 0.06 [0.03, 0.09] for proximal revisions, and 0.06 [0.03, 0.09] for distal. With differential pressure valves (DPVs) with antisiphon control, meta-analysis showed an incidence of 0.10 [0.07, 0.13] for SDEs, 0.02 [0.01, 0.04] for surgical SDEs, 0.03 [0.01, 0.05] for proximal and 0.04 [0.02, 0.07] for distal revisions. With DPVs without antisiphon control, there was an incidence of 0.17 [0.11, 0.23] for SDEs, 0.11 [0.06, 0.19] for surgical SDEs, 0.00 [0.00, 0.02] for proximal shunt revisions, and 0.05 [0.02, 0.10] for distal shunt revisions. With flow regulated valves, there was an incidence of 0.05 [0.01, 0.12] for SDEs, 0.01 [0.00, 0.05] for surgical SDEs, 0.06 [0.02, 0.11] for proximal revisions, and 0.01 [0.00, 0.05] for distal.

Gravitational valves and NPVs are associated with fewer SDEs while DPVs with and without ASDs are associated with more while there were no differences in proximal or distal revisions.