内直肌超常量后徙和继发性外斜视的关系

The relation of the medial rectus muscle supernormal recession and consecutive exotropia

目的 研究内直肌超常量后徙与继发性外斜视的关系.方法 对2003～2009年住院的43例内斜术后继发外斜的病人进行回顾性分析,分别观察常规量内直肌后徙（内直肌附着点距角膜缘的距离≤11.5mm）和超常量内直肌后徙（内直肌附着点距角膜缘的距离＞11.5mm）与眼球运动和继发性外斜视的关系.结果 13例眼球内转受限,其中发现内直肌常规量后徙33例中只有3例眼球内转受限,超常量内直肌后徙的10例患者均有眼球运动受限,经x2检验,P＜0.05;对10例内直肌超常量后徙的患者6例行内直肌前徙,术后眼球运动无受限,眼位正位;而经同等手术量内直肌缩短的4例患者中只有1例术后眼球内转轻度受限,但术后眼位正位.另外3例患者术后眼球运动仍明显受限,残留外斜视.39例术中内直肌附着点距角膜缘的距离≤11.5mm,35例（89.7%）术后正位,4例内直肌附着点距角膜缘的距离＞11.5mm,术后只有1例（25%）正位.结论 （1）内直肌超常量后徙可造成术后眼球运动受限,从而导致继发性外斜视.（2）单纯内直肌缩短术后斜视度不稳定,外直肌后徙联合后徙的内直肌前徙是治疗继发性外斜视的有效方式.

Objective To review the relation of the medial rectus muscle supernormal recession and consecutive exotropia. Methods The chart review of 43 patients who underwent surgery for consecutive extropia in a pediatric ophthalmology practice between 2003 and 2009 was performed retrospectively. To study the relation of the medial rectus muscle normal recession （medial rectus muscle placement from the limbus was ≤ 11.5mm） and supernormal recession （medial rectus muscle placement from the limbus was 〉 11.5mm） with consecutive exotropia and limitation of adduction. Results Thirteen patients had limitation of adduction, among them, 3/33 patients had a medial rectus muscle normal recession, and 10 patients had supernormal recession. The difference was significant according to the x2 test P 〈0.05. For 10 patients who had supernormal recession with limitation of adduction, among them, 6 patients readvancement of the medial rectus muscle obtained a suitable ocular alignment and with normal of adduction after operation, 4 patients who were resection of the medial rectus muscle, 1 patient had mild limitations of adduction, but had a suitable ocular alignment, the other 3 patients who persisted in limitation of adduction and consecutive exotropia. Of 39 patients who were medial rectus muscle placement from the limbus was ≤ 11.5mm, 35 patients （89.7%） had a suitable ocular alignment after operation; 4 patients who were medial rectus muscle placement from the limbus was 〉11.5 mm, only 1 patient （25%） had a suitable ocular alignment after operation. Conclusions The medial rectus muscle supemormal recession in patients with a residual limitation of adduction and the major reason of consecutive exotropia is a residual limitation of adduction. Only resection of the medial rectus muscle postoperative ocular alignment would drift, we recommend lateral rectus recession with medial rectus muscle advancement of the previously recessed medial rectus as a suitable procedure.