Preoperative identification of the initial burr hole site in retrosigmoid craniotomies: A teaching and technical note

When fashioning a retrosigmoid craniotomy, precise placement of the initial burr hole is crucial to avoid iatrogenic sinusal injury and to facilitate a corridor that allows for minimal cerebellar retraction.

3D CT reconstructions of 16 cadaveric sides were used to identify and measure three discrete anatomical points. These three points and distances between them were plotted onto the surface of the skull using a digital caliper to identify the optimal burr hole location. This technique was subsequently applied in 20 clinical cases.

Optimal burr hole placement was achieved in 87.5% of specimens and, with minor refinement, 100% of clinical cases with no significant increase in operative time. Preoperative planning took an average of 10 minutes.

This technique for localizing the location of the initial retrosigmoid burr hole is a simple, safe, reliable, rapid, and inexpensive solution for surgeons who do not have regular access to neuronavigation.