Effects of unilateral lateral rectus recession according to the tendon width in intermittent exotropia

Abstract

Purpose To verify the effect of unilateral lateral rectus recession for each millimeter according to the tendon width in intermittent exotropia. Methods A total of 37 patients (37 eyes) of 7 to 11 years of age with basic-type intermittent exotropia and a deviation of 16-25 Prism Diopters (PD) were included in this study. Under general anaesthesia, the tendon width of the lateral rectus of the deviating eye near insertion was measured with calipers, prior to dissection of the muscle tendon from the sclera. Patients underwent 6.5-10 mm unilateral lateral rectus recession. The effect of lateral recession for each millimeter was the absolute value of the angle of preoperative deviation plus postoperative deviation on the second day divided by the total amount of recession. Results Mean tendon width of the lateral rectus of a deviating eye was 8.3 mm (range: 6.5-9.5). The mean effect per millimeter of unilateral rectus recession in those 37 patient was 2.9870.42 PD (range: 2.4-4.1). The effect of recession was larger in cases in which the tendon width of the lateral rectus was narrower (P ¼ 0.000, r ¼ 0.72). Conclusion The tendon width of the lateral rectus muscle can be a useful indicator to estimate the effect of lateral rectus recession in intermittent exotropia.

Bilateral lateral rectus recession considering the tendon width in intermittent exotropia

“…The authors noted that an earlier excessive innervation to the lateral recti can lead to hypertrophy and that the tendon width of lateral rectus might speak for the hypertrophy of the muscles. 1,17 Therefore, the effects of the lateral rectus recession increase as the tendon width decreases, even though the differences are subtle.…”

“…One of the authors has reported this earlier in patients who underwent unilateral lateral rectus recession for the basic type of intermittent exotropia. 1 The aim of this study was to determine whether the tendon width of the lateral rectus would predict the effects of bilateral lateral rectus (BLR) recession to facilitate the appropriate amount of overcorrection as the surgeon desires in the early postoperative period.…”

“…The hypothetical effects were defined as 3 PD when the tendon width was 8-8.5 mm; 3.5 PD when it was 7-7.5 mm; and 2.5 PD when it was 9-9.5 mm, based upon earlier statistical analysis. 1 We compared both effects using a paired t-test. Results The mean difference between the actual and the hypothetical effects of BLR recession in all patients was 2.88 PD (P ¼ 0.001, range: 0-5.50 PD).…”

“…1 The aim of this study was to determine whether the tendon width of lateral rectus would be useful for predicting the effect of bilateral lateral rectus (BLR) recession. Methods We studied a total of 45 patients between 3 and 15 years of age who had undergone bilateral rectus recession for the basic type of intermittent exotropia.…”

The tendon width of lateral rectus muscle in predicting the effect of recession: is it just age-related artifact?

“…1,2 The mean effect of 1 mm lateral rectus recession has been shown to range from 2.7 to 3.5 preoperative deviation (PD) according to tendon width and the effect of recession has been shown to be larger in cases in which the lateral rectus tendon width is narrower because the tendon width might speak for muscle hypertrophy or contracture from increased innervation on the lateral rectus muscles in exotropia. 1,3 One of the authors (SK) previously reported this finding in patients aged from 3 to 15, who underwent unilateral or bilateral lateral rectus (BLR) recession for the basic type of intermittent exotropia. 2 However, authors were afraid of the possibility of the tendon width of the lateral rectus muscle being an artifact that reflects a growth pattern of an eyeball component.…”