間欠性外斜視の術後成績—両眼外直筋後転術と片眼外直筋後転術の比較

The surgical management of intermittent exotropia: comparison of bilateral and unilateral rectus muscles

要約　目的：小児の間欠性外斜視に対して行った両眼外直筋後転術（以下，両眼後転術）と片眼外直筋後転術（以下，片眼後転術）の術後成績と，それらに影響する因子について明らかにする。

対象と方法：福岡市立こども病院で間欠性外斜視に対し両眼後転術もしくは片眼後転術を行い，術後3〜6か月の間に術後評価を行うことができた小児184例を対象とした。手術は基本的に斜視角30Δ以下を片眼後転術とし，それ以上は両眼後転術を選択した。検討項目は，術前眼位，後転量，年齢，術後眼位，矯正効果，整容的治癒（≦15Δ）とし，手術効果に影響する因子について後ろ向きに検討した。

結果：両眼後転術群と片眼後転術群で有意差があったのは，術前眼位，術後眼位，片眼あたりの後転量，矯正効果であった。術後眼位は，両眼後転術群は9.4Δ，片眼後転術群は12.6Δであった。矯正効果は，両眼後転術群は2.1Δ/mm，片眼後転術群は1.5Δ/mmであり，両群とも年齢による影響は認めなかった。整容的治癒率に有意差はなかったが，片眼手術の場合には整容的治癒に至らなかった群は，治癒群と比較して術前斜視角が有意に大きかった。

結論：両眼後転術群と片眼後転術群の整容的治癒率は同等であったが，片眼後転術の適応をより小さい斜視角の症例とすることで，より良い成績が得られると考えられた。

Abstract　Purpose：To compare the surgical outcomes of unilateral versus bilateral rectus recession for the correction of intermittent exotropia in children.

Method：A total of 184 patients who underwent unilateral or bilateral recession were included. Patient with exotropia of≦30Δ underwent unilateral surgery and the others underwent bilateral surgery. Ocular deviations before and after surgery, the age at surgery, the size of the surgical operations, surgical effect（Δ/mm）, and surgical success, defined as a deviation of≦15Δ, were studied retrospectively. Surgical results of both groups were compared 3-6 months postoperatively.

Results：Of the 184 patients, 131 underwent bilateral surgery and 53 underwent unilateral surgery. Deviations before and after surgery, the size of the surgical operations, and surgical effect（Δ/mm）showed statistically significant differences. The mean postoperative exotropia was 9.4Δ in the bilateral group and 12.6Δ in the unilateral group. The surgical effect was 2.1Δ/mm in the bilateral group and 1.5Δ/mm in the unilateral group, but this change did not depend on the age of the patients during surgery. The success rates were not significantly different in the both groups, but a large preoperative deviation reduced the probability of surgical success in unilateral surgery.

Conclusion：Unilateral and bilateral surgeries are equally effective in exotropia. It was thought that the surgical results improved when unilateral surgery is performed for the patients with small-angle exotropia.