Single medial rectus muscle advancement in stretched scar consecutive exotropia

To evaluate the results of advancing the medial rectus muscle alone in cases of consecutive exotropia due to a stretched medial rectus muscle attachment scar.

Between 2003 and 2008, 12 eyes of 11 patients who underwent single muscle surgery for stretched scar consecutive exotropia were identified. Case notes were reviewed retrospectively. The primary outcome measure was the proportion of patients achieving the desired postoperative distance alignment of between 0Delta and 10Delta esotropia at 4 months.

The mean angle of deviation for distance prior to surgery was 33.1Delta exotropia. Limitation of adduction ranged from 0.0 to -3.5. At surgery, the medial rectus muscle was found at a mean of 16.5 mm from the limbus and advanced a mean of 8.6 mm. Adjustable sutures were used in 10 eyes. Two patients had postoperative adjustment due to an initial overcorrection of greater than 20Delta. Both developed a recurrence of exotropia. Three patients in this series achieved the desired postoperative alignment. Some had good or acceptable results, with surgery resulting in distance deviations within 10(Delta) of orthotropia in 7 cases.

In this series, excising the stretched scar and advancing the medial rectus muscle alone left the majority of patients with a residual small angle exotropia. Routine recession of the antagonist may therefore also be required, and further studies adopting this approach are called for.