Retrosigmoid keyhole approach to the posterior cranial fossa: an anatomical and clinical study

The purpose of this study is to describe the microsurgical anatomic features, as well as the operative technique for the retrosigmoid keyhole (RSK) approach to the posterior cranial fossa. In the anatomical study, 6 cadaveric heads were dissected to simulate the RSK approach. In the clinical study, the records for 15 patients treated using the RSK approach were examined. We found both conventional and RSK procedures expose the regions superior to the anterolateral margin of the tentorium, inferior to the foramen magnum, and medial to the anterolateral pons and medulla. Clinically, total removal was achieved in 13 out of 15 patients. We feel it is a safe, succinct, and minimally invasive alternative to the traditional retrosigmoid approach in selected patients.