Clinical Presentation Patterns and Outcomes of Decompression for Suprascapular Neuropathy: A Retrospective Surgical Series.

BACKGROUND

Suprascapular neuropathy caused by nerve compression or tension at the suprascapular notch is an uncommon but often underappreciated source of shoulder pain and weakness, with limited reporting of presentation types, diagnostic algorithms, and outcomes of surgical treatment.

QUESTIONS/PURPOSES

(1) How does suspected suprascapular nerve compression without rotator cuff tear or space-occupying lesion present in a predominantly young and active military population? (2) How does arthroscopic suprascapular nerve decompression affect VAS pain scores, shoulder motor grading, and return to military duty or sport in this population?

METHODS

Between 2013 and 2020, two surgeons treated 29 patients for symptoms attributed to suprascapular nerve lesions with arthroscopic suprascapular nerve decompression. The diagnosis was made by a combination of history, physical examination, MRI, and selective use of EMG and diagnostic injection. Ultrasound-guided suprascapular nerve injection at the suprascapular notch with local anesthetic was performed in all patients presenting predominantly with pain to support the diagnosis. Patients who had positive findings from this work-up were offered surgical decompression, with patients presenting predominantly with pain having completed at least 7 months of nonoperative treatment at the time of final diagnosis. Although we do not have the exact numbers, the large majority of patients whose work-up suggested the presence of these nerve lesions underwent surgical decompression. We excluded nine of the original 29 patients because they had concomitant procedures and/or were over the age of 60 years. The remaining 20 patients (median [IQR] age 23 years [21 to 28]; 15 were men) were treated with isolated arthroscopic suprascapular nerve decompression at the suprascapular notch with necessary concomitant subacromial decompression, and all of them had follow-up of a minimum of 2 years (median [range] 6 years [2 to 10]) with respect to the endpoint of VAS pain, motor grading, and return to duty or sport. To answer our first research question, we characterized the patients' presentations descriptively based on whether they presented principally with pain or with weakness. Patients presenting predominantly with pain had VAS pain scores ranging from 4 to 8 with motor grades no worse than 4+ of 5, while patients presenting predominantly with weakness had a motor grading of 4 of 5 or worse and VAS pain scores ranging from 0 to 5 (median and mode 0). To answer our second research question, we collected the following outcome measures: return to active-duty military service, shoulder abduction and external rotation strength (by motor grade), and VAS pain score (worst level at rest or activity). These outcomes were compared with Wilcoxon rank sum tests.

RESULTS

We found two clinical patterns. A primary symptom of weakness was present in 10 of 20 patients, and pain was the main symptom in 10 of 20 patients. Supraspinatus and/or infraspinatus edema and/or atrophy were present on MRI in 10 of 10 patients with weakness and 0 of 10 patients with pain. EMG had denervation changes in 8 of 8 patients with weakness and 0 of 4 patients with pain. Postoperatively, patients who primarily reported pain had improvement in median (IQR) VAS scores (6 [4 to 7] to 1 [0 to 1]; p = 0.009), whereas those who primarily reported weakness had improvement in abduction and external rotation motor grading (4.0 [3.6 to 4.0] to 5.0 [4.8 to 5.0] and 3.3 [3.0 to 3.9] to 4.3 [4.0 to 5.0], respectively; p = 0.004 and p = 0.008). Return to duty or sport occurred in 8 of 10 patients presenting predominantly with pain and 9 of 10 patients presenting predominantly with weakness at a median (IQR) of 13 weeks (13 to 17) and was maintained past at least 1-year follow-up.

CONCLUSION

In this young, active cohort, suspected suprascapular neuropathy caused by compression at the suprascapular notch presented with one of two primary symptoms: pain or weakness. Diagnosis can be supported by concordant findings on history, physical examination, and MRI, with selective use of EMG for weakness and diagnostic injection for pain. Outcomes after arthroscopic suprascapular nerve release with necessary concomitant subacromial decompression involved successful pain relief and strength improvement in patients presenting with pain and weakness, respectively. Future studies could provide valuable insight into the epidemiology of suprascapular neuropathy and further define thresholds for surgical treatment, especially for patients presenting predominantly with pain.

LEVEL OF EVIDENCE

Level III, therapeutic study.