Successful Radiofrequency Lesioning of the Pallidothalamic Tract in Paretic Form Focal Hand Dystonia With Paradoxical Unexpected Response to Intraoperative Test Electrical Stimulation: A Case Report

We report a case with paretic focal hand dystonia, which at first glance was diagnosed as writer's cramp, with poor performance only when playing the guitar and writing but with increased muscle tension around the elbow rather than in the fingers and hands. The muscle tension was around the elbow and the pallidothalamic tract (PTT) was selected as the proximal muscle target with less permanent complications. During the operation, the PTT test electrical stimulation was impaired only for guitar playing, but not for other hand movements. Therefore, test lesioning at a lower temperature and for a shorter time improved the symptoms, so we were convinced that this was the target site and coagulated this site, i.e., the PPT, at the usual temperature and time. With only one target lesioning, the patient's symptoms disappeared for six months. Careful history taking and physical examination to identify the site of muscle tension is important in determining the target of paretic form dystonia. In addition, test lesioning at a lower temperature and for a shorter time is useful if the test electrical stimulation produces a paradoxically unexpected response.