脳性麻痺股関節亜脱臼に対する股関節周囲筋解離術の手術時年齢による成績の検討

Soft-tissue Releases to Treat Spastic Hip Subluxation in Children with Cerebral Palsy : Effect of Age at the Time of Surgery

要旨　【目的】脳性麻痺の運動機能の問題に筋のインバランスがあり，股関節周囲では屈筋・内転筋が優位となり股関節脱臼が生じる．放置すると屈曲内転拘縮が進行して様々な障害を招くため，早期から予防に努めることが重要である．手術的治療の1つとして選択的筋解離術があり，その有効性は示されているが手術時期について一致した見解はない．そこで年齢による成績の違いを調べた．【対象と方法】当センターで股関節周囲筋解離術（松尾の方法を一部改変）を行い6カ月以上経過観察ができた26例52股．術後はギプスや補装具を用いて外転位を保持した．股関節単純Ｘ線写真でMP（migration percentage）を計測し，改善率（術前MP－最終観察時MP/術前MP×100％）を比較した．【結果】手術時年齢6歳未満の方が，6歳以上に比べて改善率が高かった．【結論】6歳未満での手術が良好な成績につながると考えられる．

Abstract　Objectives : Muscle imbalance poses a problem for adequate motor function in patients with cerebral palsy. The adductor and flexor muscles around the hip become dominant, leading to a high risk of hip dislocation. When left untreated, flexion and adduction contracture progresses, leading to various impairments ; hence, it is important to undertake preventive measures at an early stage. Selective muscle release is one form of surgical treatment that has been proven effective, but there is no consensus on the timing of the surgery. Here, we investigated the difference in outcome after muscle release surgery with respect to age. Subjects and methods : The subjects were 26 patients (52 hips) from our medical center who underwent muscle release (partial modification of Matsuo's method) around the hip and were followed up for at least 6 months. Abduction was retained postoperatively by using a cast or prosthetic device. Migration percentage (MP) was measured by simple hip radiography image, and the rates of improvement (preoperative MP-final MP during observation/preoperative MP×100％) were compared. Results : Higher rates of improvement were observed among patients aged 5 years or less at the time of surgery than those among patients aged 6 years or more. Conclusion : We consider that surgery performed at the age of 5 years or less could lead to favorable results.