Frame-Based Stereotactic Endoscopic Third Ventriculostomy—Toward Improved Precision and Minimizing Morbidities

Abstract

Endoscopic third ventriculostomy (ETV) is a widely accepted treatment for obstructive hydrocephalus. For most practitioners, this procedure will be performed without navigation guidance. Without such guidance, the complications associated with the procedure have ranged from 1% to 8%. We hypothesized that the discrepancy between the surface bony anatomy and internal cranial anatomy contributes to the morbidities associated with ETV. We tested this hypothesis by comparing the position of the entry point defined by the classic Kocher's point relative to the ideal entry point that would result in no manipulation of the endoscope defined by frame-based stereotaxis. The cranial computed tomography scan of 58patients who had undergone frame-based stereotactic ETV was reformatted into 3-dimensional renderings. The location of this entry point was compared with the Kocher point, as determined by the external bony anatomy. Overall, >70% of the burr holes that provided an ideal trajectory to the third ventricle were ≥0.5 cm from the Kocher point in both the sagittal and the coronal planes. Median deviations of 0.74 and 0.81 cm in the coronal (P < 0.01) and sagittal (P < 0.0001) planes were observed. The use of stereotactic endoscopic techniques increase the safety of third ventriculostomy by adding precision and reducing otherwise unnecessary surgical maneuvering.