Simple and safe exposure of the sigmoid sinus with presigmoid approaches.

Although entire exposure of the sigmoid sinus has been recognized as a complicated procedure in presigmoid approaches, we developed a new technique to expose the sigmoid sinus quite safely and simply without tough bone work. This study aims to demonstrate our technique in detail and present the effect of the procedure. Between January 2004 and December 2010, 77 patients underwent operations via presigmoid approaches in our institute. In all cases, the sigmoid sinus was completely exposed with our new surgical technique. The key step to expose the sigmoid sinus in our technique is dissection of the sinus from the overlying inner cortical bone in an antegrade direction from the junction of the transverse-sigmoid sinus to the jugular bulb using a bone dissector, avoiding meticulous bone drilling. We retrospectively examined a surgical video of all cases and determined the operative time required to entirely expose the sigmoid sinus from the transverse-sigmoid junction to the jugular bulb. In all 77 cases, the sigmoid sinuses were safely exposed with our new technique, and there was no episode of sinus injury. The operative time required to expose the sigmoid sinus ranged from 9.4 to 28.2 min (mean, 14.5 min). Standard drilling techniques took 32.3 min (range, 18.4-46.6 min) in last 20 cases before adoption of new technique. The new technique significantly shortened the surgical time to expose the sigmoid sinus (p < 0.01, Welch's t test). Our new technique is very useful for safely and simply exposing the sigmoid sinus, especially for standard neurosurgeons.