Surgical instrument tracking optimizes trans-sphenoidal endoscopic treatment of petrous apex cholesterol granuloma.

During endoscopic trans-sphenoidal treatment of petrous apex cholesterol granuloma, the challenge for the surgeon is to drill the posterior wall of the sphenoid sinus to reach the lesion while attempting to avoid the internal carotid artery (ICA). A refined neuronavigation technique is presented that diminishes bonework needed for exposure and marsupialization, and simultaneously minimizes risks of accidental harm to the ICA. The technique utilizes real-time intraoperative instrument tracking of a drill, enabling safe creation of a direct canal toward the cyst just medial to the paraclival ICA and of a curette for entirely image-guided marsupialization of the cyst's deep areas through the canal.