Localización preoperatoria de la trepanación inicial en el abordaje retrosigmoideo. Revisión de literatura y aplicación quirúrgica

Abstract

Objective: To assess an effective and reproducible technique that allows determining the emplacement of the initial burr-hole in the retrosigmoid approach.
Materials and methods: A sample of 22 patients was used to analyze the relation among the transverse - sigmoid transition (TTS), the asterion and the digastric groove. All cases had a thin-slice, 1-mm-thick Computed Tomography (CT). Patients were subdivided into two groups. Group 1: patients with variable pathologies, without structural modification of posterior fossa anatomy. Group 2: patients in which a retrosigmoid approach was performed with preoperative surgical planning of the initial burr-hole.
Discussion: Bone references (asterion and digastric point) could be identified in the totality of the analyzed 3D CT. The distances were measured using a coordinate system. TTS was recorded in 78% of the cases inferior and anterior to the asterion. In no case the TTS was found superior to the asterion. It was 0 mm to 25.5 mm (mean 12.5 mm) inferior; and a distance between -6.41mm to 14.5mm (mean 4.09mm) in the anteroposterior plane was recorded, demonstrating a large individual variability. In group 2, the location of the TTS could be accurately predicted, exposing it with the initial burr-hole.
Conclusion: A simple, effective and access free method is described, which allows the emplacement of the keyhole in the retrosigmoid approach.