Medial thalamotomy with the Leksell Gamma Knife for treatment of chronic pain.

The authors describe 10 patients who underwent stereotactic medial thalamotomy with the Leksell Gamma Knife for treatment of chronic intractable pain. The pain was related to structural spinal disorders (4), postherpetic neuralgia (2), spinal cord injury (1), thalamic syndrome (1), anesthesia dolorosa of the face (1), and brainstem infarction (1). All patients had undergone extensive treatment with a variety of modalities prior to gamma thalamotomy. Nine patients underwent unilateral and one patient bilateral lesions. Magnetic resonance imaging (MRI) was used for target localization and the lesions were directed toward the intralaminar nuclei, the lateral portion of the medial dorsal nucleus, the centrum medianum and parafascicular nuclei. The lesions were made with radiation doses of 160-180 Gy using a 4 mm beam collimator and either a single isocenter (1 patient) or two isocenters (9 patients). Follow-up MRI scans in all patients showed well localized lesions. Three patients experienced excellent pain relief, four had good pain relief and three were failures. No complications were seen in any of the patients. In the past gamma thalamotomy was used mainly for treatment of pain related to malignancies but our results indicate that it may also be a safe and effective treatment for pain of nonmalignant origin as well.