Evaluation of shunt malfunction using shunt site reservoir

Objective: To determine the usefulness of a separate reservoir placed at th e site of the shunt in evaluation of shunt malfunction . Methods and Materi als A ventricular catheter was placed alongside the proximal catheter of th e shunt and connected to a subgaleal reservoir in 17 patients, in 9 a doubl e-lumen catheter with integrated reservoir and in 13 patients a dual cathet er with a double-port reservoir was used. At presentation of suspected shun t malfunction, a standard shunt function evaluation using shunt tap, CT sca n or shunt injection was performed, and subsequently, the pressure from the tap of the reservoir was obtained. Results: Thirty-three patients presente d with symptoms of malfunction at an interval of 2.3 +/- 3 months (range 2- 429 days). The pretest probability of shunt malfunction in this population was 73%, Posttest probability of shunt malfunction was 82.5% with standard evaluation and improved to 100% by the separate reservoir tap pressure meas urement. In 4 patients in whom the shunt tap was dry, shunt infection was d iagnosed prior to revision using CSF obtained at the reservoir tap. In 5 pa tients with proximal malfunction and bradycardia, the reservoir tap allowed early ventricular lar decompression. Conclusion Th is study shows that res ervoir placed at the site of the shunt remains patient even when the shunt malfunctions, suggesting that flow rather than catheter position is importa nt in proximal malfunction. It is superior to shunt tap for detection of sh unt malfunction and infection, and it allows early ventricular decompressio n in a sick patient awaiting surgery for shunt revision. Copyright (C) 2000 S. Karger AG, Basel.