Deep brain stimulation in mesencephalic lemniscus medialis for chronic pain.

Stereotactic deep brain stimulation (DBS) with chronically implanted special devices intermittently activated by the patient himself has led to a new concept in the treatment of chronic central pain, such as the thalamic pain syndrome, herpes-zoster neuralgia, anaesthesia dolorosa, radicular and plexus lacerations, stump pain with and without causalgia and cancer pain. Our results in 32 cases (March 31, 1979) with lemniscus medialis stimulation, including the specific and nonspecific somatosensory nuclei or periaqueductal gray matter show in 53% of our cases, a reduction of pain of over 50%. The follow-up period was 47 months. These results are better than those obtained from stimulating only one of the systems. Mesencephalic lemniscus medialis DBS, introduced by one of the authors (Mundinger), leads to a functional blockade of spinothalamic, lemniscus medialis and spino-reticular systems. In cases where a positive morphine test had been done previously, endorphin secretion also plays a role. It is assumed that the effect of endorphin production lasts longer than the stimulation itself, especially in periaqueductal mesencephalic gray matter and medial pulvinar stimulation.