Motor Recovery of the Suprascapular Nerve after Arthroscopic Decompression in the Scapular Notch - a Systematic Review.

BACKGROUND

The suprascapular nerve can be compromised as a result of a compression syndrome in different locations. A (proximal) compression within the scapular notch can lead to dorsal shoulder pain and simultaneous weakness of the infraspinatus and supraspinatus muscles. By transection of the lig. transversum this compression syndrome can be treated. By means of a systematic review, the present work analyzes the motor recovery potential after arthroscopic decompression.

MATERIAL AND METHODS

A systematic review of the U. S. National Library of Medicine/National Institutes of Health (PubMed) database and the Cochrane Library was performed using the PRISMA checklist. The search words used were "suprascapular" and "arthroscopic"; "suprascapular" and "arthroscopy". Based on the evaluated literature, articles in English with at least a partial arthroscopic case series from 4 cases on and a compression syndrome of the suprascapular nerve treated with arthroscopic decompression in the scapular notch were identified. Motor recovery was described by means of EMG, clinical strength and MRI.

RESULTS

Primarily 408 hits were generated. Six articles met the inclusion criteria and were further analyzed. The number of arthroscopic cases was between 4 and a maximum of 27. The level of evidence was between III and IV. The majority of the reported clinical results were good. Motor recovery as measured by EMG was observed, recovery of full strength was not achieved in the majority of reported cases (60%), neither was regression of structural (fatty) degeneration of the muscle bellies.

CONCLUSION

Arthroscopic decompression of the suprascapular nerve in the scapular notch provides good clinical results and considerable pain relief. However, in the majority of cases it does not lead to a complete recovery of the strength of the supra- and infraspinatus muscles. Patients should be informed about this. An early decompression after diagnosis in the event of proximal compression within the suprascapular notch combined with beginning EMG or MRI changes appears reasonable. These beginning changes should be further defined. Future studies should develop prognostic criteria for motor recovery. Awareness regarding the diagnosis needs to be improved due to the probably time-dependent irreversibility of resulting muscular weakness.