AJSM - 2026-07-31 - Journal Article
Suprascapular Nerve Release Improves the Histological Healing Morphology and Biomechanical Strength of the Rotator Cuff in a Rat Chronic Massive Rotator Cuff Tear Model.
Zhang W, Guo Y, Wang H, Huang R, Wang Y, Sun Y
Topics
Key Takeaway
Concurrent suprascapular nerve release improved maximum load at 8 weeks and histological healing scores at both 4 and 8 weeks versus repair alone in a rat chronic massive rotator cuff tear model, with SSN entrapment detected in 70% (7/10) of shoulders after 4-week tendon transection.
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Summary
This controlled laboratory study asked whether SSN release concurrent with delayed massive rotator cuff repair improves tendon healing in a rat model. After 4-week bilateral supraspinatus/infraspinatus transection, 28 rats were randomized to tendon repair alone versus repair plus SSN release, with biomechanical and histological endpoints at 4 and 8 weeks. The TR+NR group achieved significantly higher maximum load at 8 weeks and superior histological scores at both timepoints (p<0.05), with SSN entrapment confirmed in 70% of shoulders by Neurofilament-200 immunofluorescence.
Key Limitation
The rat model cannot replicate the muscle atrophy, fatty infiltration grading (Goutallier), or neuromuscular complexity of human chronic massive rotator cuff tears, limiting direct translational applicability.
Original Abstract
BACKGROUND
While suprascapular nerve (SSN) entrapment is widely recognized as a complication of massive rotator cuff tears (MRCTs), its role as an independent factor affecting tendon healing remains underreported. Additionally, the therapeutic benefit of SSN release in MRCT repair remains controversial.
PURPOSE
To investigate the incidence of SSN entrapment via histological stain and whether SSN release enhances rotator cuff healing in a rat model of delayed MRCT repair.
STUDY DESIGN
Controlled laboratory study.
METHODS
A chronic MRCT model was established in rats via bilateral transection of the supraspinatus and infraspinatus tendons. After 4 weeks, 5 rats (10 shoulders) were euthanized to assess SSN entrapment incidence via immunofluorescence staining. The remaining 28 rats were randomized into 2 groups: tendon repair (TR) group (n = 14; bilateral tendon reattachment) and tendon repair + nerve release (TR+NR) group (n = 14; same repair with concurrent SSN release). Postoperative evaluations at 4 and 8 weeks included biomechanical testing (maximum load and stiffness) and histological analysis (healing quality, nerve regeneration).
RESULTS
SSN entrapments were observed in 7 of 10 shoulders using Neurofilament-200 staining. The TR+NR group demonstrated significantly higher maximum load values at 8 weeks postrepair ( P < .05). Additionally, the TR+NR group achieved significantly superior histological scores compared to the TR group at both 4 and 8 weeks postrepair ( P < .05).
CONCLUSION
SSN release significantly improved rotator cuff healing in rats with chronic MRCTs, as evidenced by enhanced biomechanical strength and histological regeneration.
CLINICAL RELEVANCE
These findings may provide some hints supporting SSN release in patients undergoing MRCT repair.