ObjectiveTo investigate the mechanisms,diagnosis,and surgical procedures of simultaneous lesions of the rotator cuff and the brachial plexus. MethodsBetween July 2006 and June 2012,7 patients with rotator cuff tear associated with brachial plexus injury were treated.There were 3 males and 4 females with a mean age of 47.3 years (range,37-72 years).The reasons of injury were traumatic shoulder dislocation in 6 cases and falling injury from height in 1 case,with a mean disease duration of 17 days (range,5-31 days).The average American Shoulder and Elbow Surgeons (ASES) score was 55.86±9.42,and visual analogue scale (VAS) score was 7.14±1.35.There were 3 cases of large rotator cuff tears (>3 cm) and 4 cases of massive rotator cuff tears (>5 cm) according to Gerber standard;1 case had upper trunk injury of the brachial plexus and 6 cases had bundle branch injury of the brachial plexus according to GU Yudong's classification.The functional score of brachial plexus score was 7.43±1.27 according to the functional assessment standard by Hand Surgery Branch of Chinese Medical Association.All patients accepted arthroscopic rotator cuff repairing,and 1 case received surgical neurolysis of brachial plexus. ResultsAll incisions healed by first intention without complication.All the 7 patients were followed up 18 to 25 months (mean,20.4 months).The function,muscle strength,and sensation of the shoulder were improved obviously.The shoulder ASES score was 84.71±8.06 and was significantly better than preoperative score (t=-8.194,P=0.000).The VAS score was 2.71±1.50 and was significantly better than preoperative score (t=7.750,P=0.000).The functional score of brachial plexus was 14.00±1.16 and was significantly better than preoperative score (t=-11.500,P=0.000). ConclusionIt is difficult to simultaneously diagnose lesions of the rotator cuff and the brachial plexus;orthopedists should pay attention to possible patients to avoid missed diagnosis and diagnostic errors.Nerve nutrition,physical therapy,and arthroscopic rotator cuff repair can achieve good effectiveness.