Effect of Bilateral Lateral Rectus Recession in Intermittent Exotropia according to the Limbus Insertion Distance

Abstract

Purpose: The aim of this work was the evaluation of the effect of the limbus insertion distance (LID) of the lateral rectus on the surgical results of bilateral lateral rectus recession in intermittent exotropia (IXT) in children and adults. Patients and Methods: This retrospective study included 76 patients. The patients were divided into two groups: group I (age 5 -13 y), group II (>13 y). All the patients had basic type of intermittent exotropia (IXT) and all of them underwent bilateral lateral recessions according to the preoperative angle of deviation. Intraoperatively, the distance of limbus insertion was measured by surgical calipers. The dose response effect was calculated as the difference between the preoperative angle and postoperative angle divided by total amount of recession and cases were followed at 1 month, 3 months, 6 months and 12 months postoperative. Results: The mean LID in group I was (6.2 ± 0.61 mm) and (6.1 ± 0.55 mm) in group II. The mean dose response (MDR) at 1 year postoperative was (2.32 ± 0.25 mm) in group I and (2.26 ± 0.23) in group II. In patients with LID < 5.5, the mean dose response was (1.98 ± 0.26) compared with that of patients with LID > 6.25 mm who had larger mean dose response (2.52 ± 0.15). There was a significant positive correlation between the LR muscle LID and the dose-response effect. Conclusion: There is positive correlation between the LID of the LR muscle and the recession effect in bilateral lateral rectus recession in treatment of IXT.

Correlation between Limbal Insertion Distance and Surgical Effect of Lateral Rectus Recession in Cases of Intermittent Exotropia

“…In this study there was no significant difference (P=0.229) in patient's gender between the two groups. Similar findings are reported in other previous studies (6,7) .…”

“…The mean LR muscle LID in this study was 6.37 ± 2.03 mm which was comparable to that of Lee et al (12) (6.15 ± 0.6 mm) and more than Ghali et al (7) study (5.8 ± 0.7 mm). Also, the mean response-dose was 2.29 ± 0.29 in Ghali et al (7) study, which is lesser than that of our study 4.73 and 4.4 in group (I) and (II) respectively, which was similar to that of Lee et al (12) (4.3 ± 1.0) at the end of follow up period.…”

“…Differences between the groups in the studies were not statistically significant among spherical equivalent (-0.25 (-1.5-0.625) vs. 0 (0-0.125)), preoperative angle deviation (41 ± 10.6 vs. 41.36 ± 8.7) and amount of recession (8.59 ± 1.7 vs. 8.64 ± 1.3). Similar to these findings, Ghali (7) reported that comparing the various parameters before surgery, similar-aged groups showed no discernible variation in any of them.…”

“…The current research, like previous one by Ghali et al (7) , examined the LR muscle LID as a possible predictor of surgical outcome in bilateral LR recession in varying age groups. For the sake of accuracy, Lee et al (12) patients with coexisting exotropia and no lateral incomitance or large distance/near disparities were sought out and recruited.…”

“…Numerous research had looked at different elements to determine IXT surgical success or failure. Factors such as patient age, preoperative deviation angle, and elevated AC/A ratio have been previously described (7,8) . Significant positive correlations were also seen in our study between preoperative angle of deviation and mean dosage response.…”