Objective: In cases of non-communicating hydrocephalus, a combined endoscopic third ventriculostomy (ETV) and tumor biopsy might be necessary. We suggest a computer-assisted planning procedure to perform ETV and biopsy via a single burr hole.
Methods: In 15 patients with non-communicating hydrocephalus with a mass obstructing the Sylvian aqueduct, an ETV in parallel to targeting the lesion was planned to be performed via a single burr hole. Prior to surgery, a 3D MRI data set was planned to be acquired for computer-assisted planning. The lesion target points were located in the third ventricle or in the lateral ventricle. By defining the optimal entry point as single burr hole, the trajectory was calculated to cause the least amount of tissue shift at the foramen of Monro (FM) or within the hemispheric tissue. The burr hole localization was measured relative to nasion and to midline. The diagnostic yield and the success rate of ETV were evaluated.
Results: The optimal entry point for third ventricular lesions was 111 ± 17 mm to the nasion and 16 ± 11 mm to the midline. Tissue shift at the level of FM was 2.4 ± 4 mm. For targeting the floor of the third ventricle in parallel to lesions of the lateral ventricle, the entry point was at 122 ± 11 mm to the nasion and 17 ± 9 mm to the midline. Rate of diagnostic yield was 86.7%. Success rate of ETV at follow-up of 34 ± 19 months was 86.7%.
Conclusions: Performing ETV in parallel to target paraventricular lesions causing a hydrocephalus is feasible via a single burr hole by using computer-assisted planning and performing a navigated endoscopic procedure.