Outcomes in Patients Undergoing Single-trajectory Endoscopic Third Ventriculostomy and Endoscopic Biopsy for Midline Tumors Presenting with Obstructive Hydrocephalus

Object: The primary aim of this study was to evaluate the success of endoscopic third ventriculostomy (ETV) as a treatment for obstructive hydrocephalus secondary to midline tumors (midbrain, pontine, pineal, tectal plate, thalamic, and third ventricular regions). In addition, the study examined the role and value of endoscopic tumor biopsy (ETB) in the management of such cases. All surgical procedures were performed through a single-trajectory approach.

Methods: A retrospective analysis of clinical notes, operation records, and pre- and postventriculostomy neuroimaging data was performed to determine the success or failure and complications of ETV and ETB in 42 patients presenting with tumor-induced obstructive hydrocephalus. Patient data were derived from an endoscopy database initiated in 1998. The study population included 21 female and 21 male patients (mean age 37 years, range 5-77 years). All 42 patients underwent an ETV; 33 of the 42 underwent an ETV and an ETB (single-trajectory). One patient was excluded from the follow-up analysis due to rapid deterioration of his condition from tumor progression. The duration of follow up ranged from 3 to 84 months (mean 32 months). At the last follow up, 11 patients with ETVs had undergone shunt placement and two patients had undergone repeated ETVs, giving a long-term success rate of 68% (28 of 41 cases) for single ETV as a treatment for hydrocephalus at presentation. Statistical analysis revealed no significant relationship (p > 0.92) between tumor location and ETV success or failure. The mean time to ETV failure was 32 weeks. Histological examination of biopsy specimens was non-diagnostic in eight (24%) of the 33 cases in which ETB was performed. Seven of these cases involved pineal region tumors and one involved a tectal plate tumor. There was no death or major morbidity associated with ETV and ETB in this series.

Conclusions: Endoscopic third ventriculostomy is a safe and durable means of controlling hydrocephalus in tumor cases. Its success rate is high--comparable to that reported in aqueduct stenosis cases. Although ETB is probably not as accurate for diagnosis as biopsy with frame-based stereotactic guidance, it is associated with a lower mortality rate and, in the correct clinical setting, may be justifiably attempted as an initial biopsy procedure at the same time as ETV via a single-trajectory approach.