Anatomic Study of Extracranial Needle Trajectory Using Hartel Technique for Percutaneous Treatment of Trigeminal Neuralgia

OBJECTIVE: The aim of this study was to describe the anatomic trajectory of the extracranial needle for percutaneous rhizotomy and correlate this with structures at risk during such a procedure. METHODS: Six sides from 3 frozen fresh Caucasian heads were used in this study. Hartel anatomic landmarks for percutaneous trigeminal rhizotomy procedures were used. A free hand technique was then used, and intra-procedural visualization of the needle was performed with fluoroscopy. When the procedure was completed, the face was dissected along with the needle pathway up to the foramen ovale in order to evaluate for any damaged structures. RESULTS: On all sides, the needle passed lateral to the buccinator muscle and near the parotid duct to then pierce the superior head of the lateral pterygoid muscle to enter the infratemporal fossa. This placed the needle near the buccal nerve on all sides, although no direct injury was noted. Although very near, no branches of the facial nerve or artery were damaged. On 1 side, the maxillary artery was pierced. CONCLUSIONS: To our knowledge, this is the first study to describe the detailed extracranial anatomic needle pathway using the Hartel approach. Such data might help surgeons better recognize potential complications from such procedures.