Das Verhältnis des präoperativen Volumens der Hirnventrikel zum gesamten Gehirnvolumen ermöglicht die Vorhersage der postoperativen Abhängigkeit von einem VP-Shunt nach der Operation eines sporadischen Vestibularisschwannoms

Obstructive hydrocephalus (HCP) linked to vestibular schwannoma (VS) typically arises in giant VS. It is anticipated that symptoms associated with HCP will improve following the removal of the tumor. Nonetheless, a subset of patients may necessitate ongoing ventriculo-peritoneal (VP) surgery. This investigation aims to identify the factors linked to the need for CSF diversion after VS surgery in instances of persistent HCP.

We analyzed 120 sporadic VS patients who underwent surgery in our center from 2012 to 2022. 71 sporadic VS patients who underwent surgery in our center from 2012 to 2022. Koos grade 2, 3, and 4 tumors were included in the analysis. Volumetric MRI analyses of the pre- and postoperative tumor volumes, extent of resection (%), cerebellum, cerebrum, ventricle, and brainstem were performed using Brainlab Smartbrush and 3D Slicer. Total brain volume was defined as the sum of cerebrum, cerebellum and brainstem. ROC analyses were performed to identify optimum cut-off values of the volumetric data.

Permanent CSF diversion after surgery was indicated in 12 patients (16.9%). The ratio of baseline volume fraction of brain ventricles to total brain volume volume (VTB-ratio) was found to predict postoperative VP-shunt dependency. The AUC was 0.71 (95% CI: 0.51-0.91) and the optimum threshold value (p=0.047) and an EoR (<96.4%, OR: 9.1, 95%CI: 1.2-69.3, p=0.032) are independently associated with postoperative VP-shunt dependency.

Primary tumor removal remains the optimal treatment to reduce the risk of postoperative hydrocephalus necessitating VP-shunt surgery. However, patients with an increased preoperative ratio of brain ventricle volume – to – total brain volume are prone to need postoperative VP-shunt surgery and may benefit from perioperative EVD placement.