Unilateral Horizontal Rectus Muscle Recessions for Pediatric Comitant Strabismus

Introduction: Compared to bilateral horizontal rectus muscle recessions (BHR), a unilateral horizontal rectus muscle recession (UHR) confers shorter operating time and anesthesia exposure, limits complication risks to one eye, and requires less recovery from the patient. Methods: Retrospective chart review of pediatric patients who underwent unilateral medial rectus recession (UMR) for esotropia (ET), or unilateral lateral rectus recession (ULR) for exotropia (XT). Primary successes were defined as maximum distance deviation at post-operative month 3: −12 to +5 for ET, −5 to +12 for XT. Rates of postoperative horizontal incomitance (HI) >5 PD and success for small medium, and large (in mm, respectively, ET: <5, 5–6 mm, >6; XT: <8, 8–10, >10) recessions were analyzed. Results: Seventeen ETs and 40 XTs were analyzed. Overall primary success was 71.9% (p = .02). Significantly, 80% (95% CI: 67.60,92.40) XTs succeeded. ETs were equally likely to succeed (53.9%) or fail (47.1%) (p = .22). For patients without significant preoperative HI, average postoperative HI was 3.90 PD (95% CI: 0.20, 7.60) for ETs; 5.48 PD (95% CI: 3.65, 7.32) for XTs. Conclusions: UHR was 71.9% successful in treating pediatric comitant strabismus. ULR for XT, particularly small to medium deviations, was most likely to succeed. In contrast to prior reports, large UMR and ULR were less likely to succeed and post-operative incomitance was frequent but rarely clinically significant.