絞扼性肩甲上神経障害に対して微小脳神経外科的治療を行った1例

Microneurosurgical Treatment for Refractory Entrapment Neuropathy of Suprascapular Nerve:A Case Report

Ⅰ．はじめに

　肩甲上神経はC5，6神経根に由来し，腕神経叢より分枝して棘上筋，棘下筋および肩甲骨周囲の感覚を支配する．同神経の障害は肩甲骨周囲の疼痛と筋力低下で発症するため，頚椎疾患や肩関節疾患との鑑別を要する．肩甲上神経が障害される原因としてガングリオンが多く報告されているが，そのほかに整形外科領域では，上肩甲横靱帯による圧迫，スポーツなどによる肩関節の酷使，外傷などが知られている²⁾．脳神経外科領域では，脳卒中後の肩の痛みに関係することに加え，頭蓋内や頚部で副神経が損傷されることで僧帽筋が萎縮し，それにより肩甲骨が転位し，肩甲上神経が牽引されることで発症する症例が報告されている⁵⁾．

　肩甲上神経障害は脳神経外科医にとってなじみの薄い疾患であるが，われわれは上肩甲横靱帯と肩甲切痕による肩甲上神経の絞扼性神経障害に対して微小神経外科的アプローチを行い，良好な結果を得ることができた症例を経験したのでここに報告する．

　Suprascapular nerve entrapment is rarely treated by neurosurgeons in Japan. However, it is often observed in post-stroke patients and in cases of accessory nerve injury as a complication of posterior fossa craniotomy. We report a case of suprascapular nerve entrapment due to superior transverse scapular ligament, which was successfully diagnosed and surgically treated. The patient was a 66-year-old female who used be a janitor. She complained of dysesthesia around the shoulder. The diagnosis was made based on the characteristic neurological findings including pain around the scapula, supraspinatus muscle weakness, and favorable but temporary response to suprascapular nerve block. After undergoing conservative management for one and a half year, she decided to undergo the nerve decompression surgery. The surgical treatment was performed under microscope with neuromonitoring. Following surgery, the painful area was dramatically reduced. We believe that suprascapular nerve disorders can be treated with careful neurological evaluation by neurosurgeons.