Diagnosis of Ventriculoperitoneal Shunt Malfunction: A Practical Algorithm.

Objective: This study aims to present a practical method to accurately diagnose ventriculoperitoneal shunt (VPS) malfunction and to detect the exact level at which the system has failed to tailor VPS revision at that level only.

Methods: A tertiary referral single-center algorithm for diagnosis of VPS malfunction is proposed. Based on clinical symptoms and confirmed ventricular dilatation on computed tomography, the VPS reservoir is punctured; if no cerebrospinal fluid is obtained, ventricular catheter replacement is recommended. Conversely, if cerebrospinal fluid is obtained, a sample is sent for cultural examination and the macroscopic integrity of the whole system is checked via plain radiography in the angiographic suite. Then, through the injection of iodate contrast medium into the reservoir and selective exclusion of the proximal and distal catheters, the patency and correct VPS functioning are investigated.

Results: A total of 102 (56 males) patients (mean age, 41.5 years; range, 1-86 years) underwent a VPS function test from 2012 to 2018: 59 cases of VPS malfunction (57.8%) were diagnosed. Ventricular catheter obstruction/damage/displacement occurred in 12/59 patients (20.3%), valve damage in 11/59 patients (18.6%), distal catheter obstruction/damage/displacement in 17/59 patients (28.8%) and 2-level (valve/proximal catheter or valve/distal catheter) obstruction/damage/displacement in 16/59 patients (27.1%). Subclinical infection was diagnosed in 3 patients (5.1%). VPS revision was performed selectively at the level of failure.

Conclusions: The proposed algorithm is a practical, simple and minimally invasive technique to accurately diagnose VPS malfunction, identifying the exact level of system failure and allowing surgical VPS revision to be tailored, avoiding unnecessary complete system replacement.