Isolated serratus palsy etiology influences its long-term outcome.

HYPOTHESIS AND BACKGROUND: The cause of isolated serratus palsy is multifactorial, but evaluation of the mechanism of the injury indicates that the lesion to the long thoracic nerve is mechanical in origin in most cases. What is unknown, however, is how etiology influences its long-term outcome. We believed that overuse injuries may recover sooner and better than acute traumatic, infectious, or inflammatory injuries. METHODS: We determined the presumed etiology of isolated serratus palsy in 92 patients treated by brace or observation only and compared it with its long-term outcome after a mean follow-up of 18.1 years (range, 2.1-26.9) by measuring pain, range of motion, and winging of the scapula. RESULTS: Trauma preceded 22 (24%) of the cases, exertion 37 (40%), infection 14 (15%), and surgery/anesthesia 10 (11%). In 9 (10%) cases, no etiologic factor was evident. Serratus palsy preceded by infection recovered better than did cases with no infection, and those with palsy preceded by surgery/anesthesia had a poorer outcome than did those with no surgery (axilla, chest, or any other areas) or anesthesia. Those palsies caused by acute trauma or acute or chronic overuse/exertion had the same recovery course. DISCUSSION AND CONCLUSION: Etiology of isolated serratus palsy influenced long-term outcome less than we had expected. It seems, however, that palsies caused by infection recover better and those caused by surgery wherever in the body recover most poorly.

The natural course of serratus palsy at 2 to 31 years.

BACKGROUND: The natural course of isolated serratus palsy is obscure. Residual winging, muscle weakness, and fatigability reportedly occur in half of the patients. Because we believed isolated serratus palsy might have a better natural course than earlier thought, we evaluated our long-term records. QUESTIONS/PURPOSES: We determined duration of symptoms and whether scapular winging, ROM, and pain recover or persist after isolated serratus palsy without any particular treatment. METHODS: We retrospectively reviewed 37 patients with isolated serratus palsy treated by observation without any brace or surgery. We determined the degree of scapular winging, ROM, and pain. The minimum followup was 2 years (median, 18 years; range, 2-31 years) after onset of symptoms. RESULTS: The duration of scapular winging averaged 16 months (range, 2-30 months). Winging of the scapula disappeared in 29 (78%) of the patients, flexion recovered to normal in 30 (82%) and abduction in 33 (89%). Of the 37 patients, 11 (30%) were pain-free; pain at rest was absent from 17 (46%), occurred seldom in seven (19%), and was temporary in 12 (32%); one patient had pain at rest continuously. None of the patients desired other treatment such as a brace or surgery. CONCLUSIONS: The natural course of isolated serratus palsy in clinically mild cases is not as favorable as we had expected. Symptoms mostly recover in 2 years, but at least one-fourth of the patients will have long-lasting symptoms, especially pain. We could identify no factors to allow us to appropriately choose patients with serratus palsy for observation only.