(Purpose)To clarify the mechanism of suprascapular nerve palsy caused by a ganglion cyst, we examined 9 suprascapular nerve palsy patients who had surgical treatment.
(Patients and methods)The patients were 7 males and 2 females with solitary suprascapular nerve palsy. Age at onset, physical examinations, EMG, MRI and the operative findings were evaluated. (Results)The age at onset was from 22 to 54 years old with an average 33.7 years old. Their symptoms were dull pain and pain during movement of their shoulders. There was muscle atrophy of the infraspinatus muscle(ISP)in all the cases and the supraspinatus muscle(SSP)in 6 cases. Abnormal EMG's were found in ISP in all the cases and SSP in 4 cases. According to the MRI, there were ganglion cysts on the spinoglenoid notch with a low intensity on Tl weighted images and high intensity on T2. The high signal intensity of an atrophic ISP in 3 cases on Tl and 6 cases in T2. The ganglion cysts were removed and the inferior transverse scapular ligaments were cut with the posterior approaches. The cysts were gourd spape and constricted with the inferior transverse scapular ligament and the base of the scapular spine. The genglion cysts caused compression of the suprascapular nerve under and medial of the inferior transverse scapular ligament. Ganglion cysts appeared from the labrum-joint capsule complex at the postro-superior part of the glenoid. After the operations, all the patients recovered from their palsy in spite of one recurrence of the ganglion cyst.
(Conclusion)Ganglion cysts appeared from the labrum-joint capsule complex, spread into the space under the inf. trans. scapular ligament and caused compression of the suprascapular nerve.
