Suprascapular Nerve Release Improves the Histological Healing Morphology and Biomechanical Strength of the Rotator Cuff in a Rat Chronic Massive Rotator Cuff Tear Model.

Abstract

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. 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. Controlled laboratory study. 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). 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 (<i>P</i> < .05). Additionally, the TR+NR group achieved significantly superior histological scores compared to the TR group at both 4 and 8 weeks postrepair (<i>P</i> < .05). SSN release significantly improved rotator cuff healing in rats with chronic MRCTs, as evidenced by enhanced biomechanical strength and histological regeneration. These findings may provide some hints supporting SSN release in patients undergoing MRCT repair.