Radiosurgery to the Medial Thalamus for Chronic Pain: A Single Group Experience and Review of Literature.

Introduction Chronic pain presents a significant challenge in achieving effective treatment and can greatly reduce patients' quality of life. Many individuals can undergo multiple therapies with limited success. Stereotactic medial thalamotomy is a treatment option for certain types of chronic pain when other measures have failed. This study aims to assess the efficacy and safety of radiosurgical medial thalamotomy based on nearly a decade of experience in managing chronic intractable pain of both malignant and non-malignant origins. Methods This retrospective study included 56 patients who underwent radiosurgery to the medial thalamus for refractory neuropathic pain or mixed cancer pain. Treatment approaches involved single thalamic irradiation, bilateral thalamotomy, dual-target irradiation of the medial thalamus and trigeminal nerve, or triple-target irradiation of the pituitary gland and bilateral thalami. Results Pain intensity was significantly reduced at the final follow-up for patients treated with triple-target radiosurgery (Student's t-test, p < 0.001), dual-target radiosurgery (Wilcoxon test, p < 0.001), and single/bilateral thalamotomy (Wilcoxon test, p = 0.01). The median time to pain relief was 2.5 days for triple-target treatment, three days for dual-target treatment, 1.5 days for bilateral thalamotomy, and 33 days for single thalamotomy. Overall, treatment success, defined as achieving at least 50% pain relief, was 69.1% for the entire cohort. The success rate was 66.6% for oncologic pain and 71.7% for non-oncologic pain. Conclusion Radiosurgical irradiation of the medial thalamus is an effective alternative for treating refractory cancer-related pain and predominantly neuropathic non-oncologic pain. Various radiosurgical regimens can be employed in a multi-target strategy tailored to the origin and characteristics of the pain, offering relief to most patients with minimal morbidity.