The purpose of this study was to report the results of arthroscopic decompression of ganglion cyst causing suprascapular nerve palsy. Four shoulders with suprascapular nerve palsy by ganglion cyst were evaluated. One was a professional baseball player. All patients had shoulder pain, weakness on external rotation and atrophy of the infraspinatus muscles. MRIs showed large cystic lesions adjacent to the supraglenoid notches. Posterior labrum fraying was seen in 3 cases. The symptoms (shoulder pain, weakness of muscle strength) recovered in all cases. The cysts disappeared in postoperative MRIs and no recurrences were found in MRIs. There is a risk of nerve damage, but we think this procedure is a useful method.
