Rapid recovery of serratus anterior muscle function after microneurolysis of long thoracic nerve injury

BACKGROUND Injury to the long thoracic nerve is a common cause of winging scapula. When the serratus anterior muscle is unable to function, patients often lose the ability to raise their arm overhead on the affected side. METHODS Serratus anterior function was restored through decompression, neurolysis, and tetanic electrical stimulation of the long thoracic nerve. This included partial release of constricting middle scalene fibers and microneurolysis of epineurium and perineurium of the long thoracic nerve under magnification. Abduction angle was measured on the day before and the day following surgery. RESULTS In this retrospective study of 13 neurolysis procedures of the long thoracic nerve, abduction is improved by 10% or greater within one day of surgery. The average improvement was 59 degrees (p < 0.00005). Patients had been suffering from winging scapula for 2 months to 12 years. The improvement in abduction is maintained at last follow-up, and winging is also reduced. CONCLUSION In a notable number of cases, decompression and neurolysis of the long thoracic nerve leads to rapid improvements in winging scapula and the associated limitations on shoulder movement. The duration of the injury and the speed of improvement lead us to conclude that axonal channel defects can potentially exist that do not lead to Wallerian degeneration and yet cause a clear decrease in function.