内転時の上斜筋過動を伴うA型外斜視に対する上斜筋腱延長術の手術効果の検討

The efficacy of superior oblique tendon lengthening for A-pattern strabismus with superior oblique muscle overaction

要約　目的：内下方視時の上斜筋過動を伴うA型外斜視に対する上斜筋腱延長術の手術効果を検討する。

対象と方法：2018年7月〜2022年1月に名古屋大学医学部附属病院で両上斜筋腱延長術を行った9例18眼（男性4例，女性5例）を対象とし，診療録から年齢，性別，術式，術前後の眼球運動，斜視角，立体視，眼球回旋の程度を抽出し，合併症の有無，両上斜筋腱延長術前後の眼球運動，斜視角，立体視，眼球回旋をマン・ホイットニーのU検定を用いて比較した。p＜0.05を有意差ありとした。

結果：内下方視時の下斜筋過動，垂直斜視角，眼球回旋は有意差がなく，内転時の上斜筋過動，術前後の水平斜視角の上下差，立体視は有意に改善した。術後合併症はみられなかった。

結論：両上斜筋過動を伴うA型外斜視に対する上斜筋腱延長術は，有意に上斜筋過動，Aパターンを改善したが，術後の垂直斜視角，眼球回旋の程度に対しては影響を与えなかった。内転時の下転過動を伴うA型外斜視に対して上斜筋腱延長術を行い，良好な術後成績が得られた。

Abstract　Purpose：To examine the efficacy of superior oblique tendon weakening procedure for A-pattern exotropia with downshoot in adduction（SOOA）.

Methods：Nine patients（male, 4；female, 5）who underwent superior oblique tendon elongation by chicken suture at Nagoya University Hospital between July 2018 and January 2022, were enrolled in this study. Data on patients' age, sex, type of surgery, pre- and postoperative eye movements, extent of horizontal and vertical deviations in three directions, vertically, stereopsis, and objective torsions were extracted from their clinical records retrospectively. The degree of SOOA and upshoot in adduction（IOOA）, horizontal and vertical deviation, stereopsis, and objective torsions before and after surgery were compared using Mann-Whitney's U test. A p-value of＜0.05 was considered to indicate statistical significance.

Results：There were no significant differences in the degree of IOOA, vertical deviation, and objective torsions. While significant differences existed in the degree of SOOA, difference in the degree of horizontal deviation in up and down gaze, and stereopsis before and after surgery, no complications were observed.

Conclusions：Our finding indicate that superior oblique tendon elongation was effective could therefore be a suitable treatment option for A-pattern strabismus.