Isolated paralysis of the serratus anterior muscle: Surgical release of the distal segment of the long thoracic nerve in 52 patients

IntroductionIsolated serratus anterior (SA) paralysis is a rare condition that is secondary to direct trauma or overuse. Patients complain of neuropathic pain and/or muscle pain secondary to overexertion of the other shoulder stabilizing muscles. As the long thoracic nerve (LTN) passes along the thorax, it can be compressed by blood vessels and/or fibrotic tissue. The goal of the current study was to evaluate the outcomes of surgical release of the distal segment of the LTN in cases of isolated SA paralysis.Patients and methodsThis was a retrospective study of 52 consecutive cases operated on between 1997 and 2012. The average patient age was 32 years (range 13–70). Patients had been suffering from paralysis for an average of 2 years (range 4–259 months); the paralysis was complete in 52% of cases. Every patient underwent a preoperative electroneuromyography (ENMG) assessment to confirm that only the SA was affected and there were no signs of re-innervation.ResultsEvery patient had abnormal intraoperative findings. There were no complications. All patients showed at least partial improvement following the procedure. The improvement was excellent or good in 45 cases (86.7%), moderate in 4 cases (7.7%) and slight in 3 cases (5.6%). In 32 cases (61.5%), the winged scapula was completely corrected; it was less prominent in 19 cases and was unchanged in one case. The best outcomes following surgical release occurred in patients who presented without preoperative or neuropathic pain and were treated within 18 months of paralysis.DiscussionIsolated SA paralysis due to mechanical injury resembles entrapment neuropathy. We discovered signs of LTN compression or restriction during surgery. Surgical release of the distal segment of the LTN is a simple, effective treatment for pain that provides complete motor recovery when performed within the first 12 months of the paralysis.Level of evidenceIV.