ID 48 – Effects of elbow position on short-segment nerve conduction study of the ulnar nerve

Abstract

Background elbow position in evaluation of the Cubital tunnel syndrome (CubTS) by short-segment nerve conduction study (SSCSs) was still under discussion. This study is to determine the effect of full extension and 70° of elbow flexion on SSCSs of the ulnar neuropathy. Method SSCSs were studied in 70 elbows from 59 CubTS patients at full extension and 70° of flexion. 30 healthy gender- and age-matched volunteers was included, and upper limit latency of each segment for abnormal standard was calculated. Result Latency and CMAP change was highly correlated between full extension and 70° of flexion by SSCSs, but can not be replaced by each other. There was no statistic significance of abnormality between full extension and 70° of flexion by SSCSs. Conclusion in our study, full extension and 70° of flexion is no better than each other in diagnosis of CubTS, both can be performed just according to the situation of the investigators. For the subjects who are highly suspected CubTS but found negative results, and whose latency or CMAP change is around upper limit by SSCSs, should perform SSCSs in the other elbow position. And results 2 cm distal to medial epicondyle should be taken carefully to diagnose CubTS.