Clinical contrast study of nerve recovery after two different surgical methods for treatment of massiverotator cuff tear with suprascapular nerve injury

Abstract

Background In recent years, the incidence of rotator cuff injury has been increasing in population. Rotator cuff injury is not only the damage of tendon, but also often associated with different levels of nerve damage.Among them, the suprascapular nerve injury is the most commonone . The suprascapular nerve runs on the fascia between supraspinatus and infraspinatus.The severe retraction and fat infiltration of supraspinatus and infraspinatuscaused by massive rotator cuff tear will pull the suprascapular nerve and result in its dysfunction.The symptomsaremanifested as the posterolateral pain of shoulder joint which radiates toward the back of neck andarm and the disability of shoulder abduction and external rotation. Clinically, the disease can be easily missed.The incidence of massive rotator cuff injury accounts for approximately 10% to 40% of all rotator cuff injuries. According to the size of tear, Cofield divided rotator cuff injury intofour types:small tear ( 5 cm) . However, 30% of rotator cuff injuries are considered to be irreparable due to massive tear, atrophy of rotator cuff and fat infiltration, and the retear of 80% of patientis massive rotator cuff tear.The cause of suprascapular nerve damage after massive rotator cuff injury is unclear, which may be related to the retraction of rotator cuff and in turn the traction of suprascapular nerve around spinoglenoid notch.Some studies pointed out that the suprascapular nerve function can be restored with simple rotator cuff repair. For massive rotator cuff injury, there are traditional double-row repair and suture bridge technology.Transposition of latissimus dorsi muscle, transposition of deltoid muscle, patch repair, reverse shoulder arthroplasty,etc.have good efficacy in the treatment of massive rotator cuff injury with severe retraction and fat infiltration. However, there is a lack of study on the recovery of nerve damage.Objective To investigate the effects of traditional double-row repair and fascia lata transposition on the functional recovery of the patient with massive rotator cuff tear with suprascapular nerve injury. Methods From January 2013 to January 2018, a total of 20 patients with massive rotator cuff tear received arthroscopic rotator cuff repair surgery in our hospital, and the data were retrospectively analyzed. There were 10 cases in traditional double-row repair group (group A) and 10 cases in fascia lata transposition group (group B) . All patients were diagnosed as massive rotator cuff injury with suprascapular nerve injury under MRI and electromyogram.The postoperative follow ups were conducted in the 1st and 6th months. Visual analogue scale (VAS) , University of California at Los Angeles (UCLA) scoring system and Constant-Murley scoring system were applied for comparison between the two groups before and 6 months after operation.The conditions of rotator cuff healing and nerve recovery were assessed by MRI and electromyogram 6 months after operation. Results Twenty patients were followed up for 6 months after surgery, and the average follow up time ranged from 6 to 18 months. Six months after operation: the VAS score of group A decreased from preoperative (7.4±0.8) points to postoperative (2.3±1.7) points with statistical difference (P<0.01) ; the UCLA score of group A increased from preoperative (11.5±1.4) points to postoperative (28.3±5.8) points with statistical difference (P<0.01) ; the Constant-Murley score of group A increased from preoperative (45.6±6.2) points to postoperative (79.0±11.7) points with statistical difference (P<0.01) ; the VAS score of group B decreased from preoperative (7.9±0.6) points to postoperative (2.7±1.8) points with statistical difference (P<0.01) ; the UCLA score of group B increased from preoperative (10.1±1.4) points to postoperative (26.9±6.9) points with statistical difference (P<0.01) ; the Constant-Murley score of group B increased from preoperative (39.0±3.4) points to postoperative (72.9±9.4) points with statistical difference (P<0.01) .Electromyogram was reviewed 6 months after operation.While there was no suprascapular nerve injury in the group A,there were 5 cases of suprascapular nerveinjury in the group B (P<0.01) . Conclusion Both the arthroscopic traditional double-row repair and the fascia lata transposition can improve shoulder function. For the patient with suprascapular nerve injury, it is believed that the traditional double-row repair can better restore suprascapular nerve function than the fascia lata transposition does.However, the risk of retearmay be high. Key words: Massive rotator cuff tear; Arthroscopy; Suprascapular nerve; Rotator cuff repair; Patch graft