SUSPECTED NEUROGENIC THORACIC OUTLET SYND ROME - DIAGNOSTIC-IMPORTANCE OF ADDITIONAL ELECTROPHYSIOLOGIC INVESTIGATIONS

The neurogenic thoracic outlet syndrome (TOS) is a controversial clini cal entity, since unambiguous diagnostic criteria are lacking and abno rmal findings are absent in many patients. To evaluate electrodiagnost ic methods a retrospective analysis was done comprising all 75 patient s with suspected TOS who had been examined electrophysiologically in o ur laboratory in the last 5 years. 35 of the 75 patients were finally diagnosed as having TOS, but only 10 of them had a corresponding elect rophysiological pathology. 6 had ''classic'' TOS with clinically obvio us sensorimotor deficits, whereas in 4 the electrophysiologic findings were the only abnormalities (in 3 of 4, only minor neurographic anoma lies were found). Proximal motor stimulation techniques did not improv e the diagnostic yield. We conclude that electrodiagnostic methods are of little value in the diagnosis of TOS if there are no clinical abno rmalities. The electrophysiological examinations did however reveal di stal entrapment neuropathies in 15 of 75 patients (12 carpal tunnel sy ndromes). The frequent detection of such neuropathies in our patients is interesting and it justifies per se electrodiagnostic examination o f the patient with suspected TOS.