Technical and anatomical aspects of novalis stereotactic radiosurgery sphenopalatine ganglionectomy

Background: Several techniques have been applied for destruction of the sphenopalatine ganglion to control cluster headache and ocular pain with sympathetic component. Cluster headache has responded to radiofrequency ablation or phenol destruction. Radiosurgery of the sphenopalatine ganglion is promising due to the excellent visualization of the target on magnetic resonance imaging (MRI), computed tomography (CT), and skull X-rays. Material and Methods: Six patients and one cadaver head were analyzed in this study. The cadaver-head dissection confirmed the location of the sphenopalatine ganglion on X-rays and CT imaging. One patient undergoing radiofrequency sphenopalatine ablation participated for confirmation of the location of the ganglion on plain X-rays. Five patients received radiosurgery of the sphenopalatine ganglion. One patient had classic unilateral cluster headache. Two patients had neuropathic pain and 1 had bilateral migrainous neuralgia. The fifth patient had bilateral atypical facial pain. All received a single maximal dose of 90 Gy with a 5- or 7.5-mm circular collimator. MRI, CT, and skull X-rays identified and confirmed the target. Results: The sphenopalatine fossa is seen in the skull X-ray as an inverse tear drop just caudal to the sphenoid sinus. This location is readily correlated to the CT target by the stereotactic coordinates and confirmed with the presence of the ganglion visualized in the MRI scan. Only the patient with cluster headache experienced lasting pain relief. Conclusion: Multiple imaging modalities confirmed the location of the sphenopalatine ganglion for radiosurgery. The procedure was performed safely with CT and MRI fusion. Radiosurgery was significantly beneficial only on classic cluster headache.