Quantitative Assessment of Scalene Muscle Block  for the Diagnosis of Suspected XXXX .

@entity1 @entity998 @entity5482 @entity531 @entity121 @entity616
PURPOSE: To measure changes in upper limb work and power capacity before and after anterior scalene @entity121 (ASMB) to suggest @entity531 caused by costoclavicular space compression. METHODS: We evaluated 34 @entity1 disabled by symptoms suggesting @entity531 . An ASMB was performed via a supraclavicular injection. The sternocleidomastoid muscle was injected as a control. We captured data obtained from work simulator measurements before and after ASMB. Each @entity1 performed a push-pull test with the forearm at waist level ( @entity5482 ), an overhead bar push-pull test with the arm elevated (test 2), and the extremity abduction stress test with repetitive hand gripping during static arm elevation (test 3). We measured the work product, time to fatigue, and power generation. Sensory testing was performed after ASMB to rule out improved performance associated with possible @entity616 . RESULTS: In contrast to sternocleidomastoid injection controls, symptomatic and functional improvement was noted in all @entity1 (n  = 34) after ASMB. Work product measurement improved 93%, 108%, and 104% for tests 1, 2, and 3, respectively. @entity998 also increased after the block. CONCLUSIONS: Temporary symptomatic improvement after ASMB may be anticipated in @entity1 with TOS. This study documents a significant concurrent increase in upper limb motor function after the block. Increased work and power measurements after ASMB may draw diagnostic inference regarding a dynamic change in the scalene muscle and the costoclavicular space associated with symptomatic @entity531 . TYPE OF STUDY/LEVEL OF EVIDENCE: Diagnostic III.
