Stereotactic Approach Combined with 3D CT Reconstruction for Difficult-to-Access Foramen Ovale on Radiofrequency Thermocoagulation of the Gasserian Ganglion for Trigeminal Neuralgia

Abstract

Objectives: The authors describe a technique that includes a stereotactic approach in the preoperative plan in cases where the foramen ovale is difficult to access for radiofrequency thermocoagulation of the Gasserian ganglion.

Methods: The study included 395 patients for whom three-dimensional computed tomographic reconstruction of the skull base, maxilla, and mandible was conducted before surgery. Accessibility of the foramen ovale was defined using numerical data from the three-dimensional computed tomographic reconstruction images. In those patients for whom accessibility of the foramen ovale was considered difficult, the authors used a stereotactic frame to design an individual operative plan. Adjustments of a single point of data,-that is, a change in X axis, Y axis, or an arc angle-were guided by radiographic fluoroscopy images. After verifying successful cannulation and electroneurophysiology, thermocoagulation targets-especially multiple targets recorded as data on the Z axis of the stereotactic approach-were identified and treated.

Results: There were 24 patients who met the predetermined criteria for having a difficult-to-access foramen ovales-that is, they had at least two contributing factors and/or involvement of division V1 . Twenty-one of the 24 patients required a single satisfactory puncture; three patients required two to three punctures to successfully access the foramen ovale. There were no permanent complications from the procedure.

Conclusions: The authors conclude that this stereotactic approach combined with three-dimensional computed tomographic reconstruction model can improve the accuracy, safety, and efficiency of percutaneous radiofrequency thermocoagulation in patients with trigeminal neuralgia for whom the foramen ovale is difficult to access.

Keywords: Computed Tomographic Reconstruction; Foramen Ovale; Radiofrequency Thermocoagulation; Stereotaxis; Trigeminal Neuralgia.