Linac-Stereotactic Radiosurgery (LSRS) in the Management of Trigeminal Neuralgia: Median 6 Year Follow-up in 51 Cases

Abstract

Stereotactic Radiosurgery (SRS) with the Gamma Knife (GK) has been used successfully in the treatment of Trigeminal Neuralgia (TN). Results have been comparable to open surgery. There have been few reports with the use LSRS in the management of TN. We report our updated results with LSRS in the treatment of TN. Between 2000 and 2010, 51 patients with medically refractory TN were treated with LSRS. Prior neurosurgical intervention had been performed in 39 patients. Twenty two patients had one procedure, 14 patients two, and 5 patients three interventions. All patients had typical TN. LSRS was given to the cranial nerve V entry root zone into the brainstem. Targeting was defined by CT and MRI Scans, and CT Cisternogram, utilizing axial and coronal images. Treatment planning was accomplished thru Radionics Treatment Planning System. The dose was 87 Gy to Dm, in one fraction using the 5 mm collimator and 6 arcs with the 20% Isodose line just touching the brainstem. This dosimetry is similar to Gamma Knife. The dose rate was 400 MU/min. Average Arc length was 130 degrees. Response to treatment was defined as excellent (no pain, off analgesics), good (no pain, with analgesics), and poor (continued pain despite analgesics). With a median follow-up of 74 months (range 54 - 132 months), 62.7% (32/51) of patients have reported an excellent or good result after LSRS. One patient has sustained permanent ipsilateral facial numbness. A 2nd patient developed anesthesia dolorosa. LSRS offers comparable results to Gamma Knife SRS in the management of TN.