Effect of Limited Tenon Capsule and Intermuscular Membranes Dissection on the Outcome of Surgery in Patients with Horizontal Strabismus

Purpose: The aim of the study was to evaluate the effect of limited dissection of Tenon capsule on the outcome of strabismus surgery.

Methods: Patients between the ages of 2 and 50 years with pure horizontal strabismus were enrolled in a prospective study. Patients were divided into two groups: case and control as a non-randomized study. The method of operation was similar in both groups except for the amount of sheath Tenon dissection. In the control group the intermuscular connections and Tenon capsule were cut as much as possible. In the study group, Tenon capsule, 3-4 mm posterior to the location of the sutures over the muscle (recessed or resected), were cut and intermuscular connections remained intact.

Results: The study enrolled 54 patients with 27 patients in each group. In both groups, after operation, regardless of the type of surgery, the angle of strabismus was reduced (P< 0.05). For patients who had undergone bimedial recession, the angle of strabismus was corrected to 2.6 ± 0.4 prism diopters per mm (PD/mm) of muscle recession in the case group, and 2.2 ± 0.9 in the control group (P=0.2). For patients who had undergone monocular recession and resection (R&R) for esotropia, the angle of strabismus was corrected 3.4 ± 0.3 PD/mm of muscle recession or resection in the case group, and 3.2 ± 0.2 in the control group (P=0.05). For patients who had undergone bilateral recession, the angle of strabismus was corrected 2.3 ± 0.2 PD/mm of muscle recession in the case group, and 2.2±0.2 in the control group (P=0.03). For patients who had undergone R&R for exotropia, the angle of strabismus was corrected 3.1 ± 0.5 PD/mm of muscle recession or resection in the case group, and 2.7 ± 0.3 in the control group (P=0.02).

Conclusion: Connective tissue ensheathments, whether disturbed or removed, do not ultimately affect the success of the strabismus surgery.