上斜筋麻痺に対する下直筋手術の長期経過

Long-term outcome of inferior rectus muscle surgery for superior oblique palsy

要約　目的：後天性の滑車神経麻痺と成人の先天上斜筋麻痺に対する健眼の下直筋手術の長期経過の報告。

対象と方法：過去38か月間に当科で上斜筋麻痺と診断され，手術を受けた126例中，後天性の滑車神経麻痺と成人の先天上斜筋麻痺で健眼の下直筋手術を1回のみ施行し，4年間の経過が追えた14例を対象とした。診療録の記述に基づき，術前，術後3か月と4年の上下と回旋眼位を検索した。

結果：第1眼位での上下偏位の平均値は，術前10.1°であり，術後3か月で0.7°，4年後に1.8°と有意に改善した。回旋偏位の平均値は，術前9.3°であり，術後3か月で1.8°，4年後に2.4°と有意に改善した。上下偏位と回旋偏位の値は，3か月後と4年後の間に有意差はなかった。第1眼位での上下偏位1mmあたりの矯正度数は，術後3か月で2.0°，4年後で1.6°であり，有意差があったが，回旋偏位の1筋幅あたりの矯正度数は，それぞれ9.4°と8.4°であり，両者間に有意差はなかった。

結論：後天性の滑車神経麻痺と成人の先天上斜筋麻痺に対する健眼の下直筋手術により，上下偏位と回旋偏位が有意に改善した。術後の眼位は，術後3か月の値が，術後4年でもほぼ保たれていた。

Abstract　Purpose：To report the long-term outcome of surgery on the inferior rectus muscle of the fellow eye for acquired trochlear nerve palsy and congenital superior oblique muscle palsy in adults.

Cases and Method：This retrospective study was made on 14 eyes who received surgery on the inferior rectus muscle of the fellow eye for acquired trochlear nerve palsy and congenital superior oblique muscle palsy in adults. These 14 eyes were among 126 cases who were diagnosed with superior oblique muscle palsy by us in the past 38 months. These 14 eyes were followed up for 4 years after surgery regarding vertical and torsional deviations.

Results：Vertical deviation at the primary position averaged 10.1 degrees before surgery. It improved to 0.7 degrees 3 months and 1.8 degrees 4 years after surgery. These values were significant when compared to values before surgery. Extorsion at the primary position averaged 9.3 degrees before surgery. It improved to 1.8 degrees 3 months and 2.4 degrees 4 years after surgery. These values were significant when compared to values before surgery. Change in vertical deviation per 1 mm of recession of inferior rectus muscle averaged 2.0 degrees after 3 months and 1.6 degrees after 4 years. The difference was significant. Change in extortion per one muscle width of transposition of inferior rectus muscle averaged 9.4 degrees after 3 months and 8.4 degrees after 4 years. The difference was not significant.

Conclusion：Surgery on the inferior rectus muscle of the fellow eye was effective for acquired trochlear palsy and congenital superior oblique muscle palsy in adults. The beneficial effect lasted for 4 years after surgery.