gms | German Medical Science

Objective: Endoscopic third ventriculostomy (ETV) is a generally accepted technique to treat symptomatic occlusive hydrocephalus. The procedure can be regarded as successful when ventricular size diminishes and patients clinically improve. With correct indication, success rate is considered to be up to 80%. Whereas several reasons for ETV-failures are described in the literature, corresponding brain pressure values usually remain unknown. Therefore, the aim of this study was to perform a long-term brain pressure monitoring after endoscopic treatment.

Method: A total of 25 telemetric ICP measurement devices (Raumedic Neurovent P-tel) were inserted in the frontal brain parenchyma of patients suffering from occlusive hydrocephalus. Aetiologies of hydrocephalus were aqueductal stenosis (n=18), posterior fossa tumor (n=4) and Chiari associated hydrocephalus (n=3). P-tel implantations were performed either a few days prior to the planned ETV (n=12) or parallel to the endoscopic procedure (n=13). After endoscopy patients were regularly followed-up with clinical examinations and telemetric ICP measurements. Recorded ICP data were investigated in a standardized form, related values of ETV-responders and -nonresponders finally compared to reveal possible differences.

Results: ETV was successful in 17 patients (68%). Related telemetric measurements showed regularly stepwise reductions of the intracranial pressure down to normal and physiological values. After an average of 1.5 months no more significant changes in ICP could be observed. Interestingly, in 50% of the pre- and postoperatively measured patients an increase in ICP was revealed at first. ETV procedure failed in 8 patients (32%). Consecutively, a shunt implantation followed in average 37 days after endoscopy (range: 2–80 days). In contrast to the successful procedures, associated ICP measurements showed physiological values immediately after surgery whereas significant increases in brain pressure could be revealed in the course of time.

Conclusions: Telemetric technique could show clear differences in brain pressure profile between ETV-responders and -nonresponders. The well-known phenomenon that clinical convalescence requires a certain time is potentially due to temporary increases in ICP after the procedure and the prolonged normalization of the brain pressure values.