Indications and Outcomes for Extraocular Muscle Disinsertion in Strabismus Surgery

To describe a case series of extraocular muscle (EOM) disinsertions, discuss the indications for muscle disinsertion, and examine deviation outcomes.

All consecutive patients who underwent EOM disinsertion by one surgeon from 2013 to 2021 were included in the study. Age, sex, best corrected visual acuity, diagnosis, preoperative deviation, postoperative deviation, and follow-up interval were recorded.

Twelve patients (13 eyes) underwent EOM disinsertion. Ten were men and two were women. Eight eyes had an abducens nerve (cranial nerve 6) palsy, four had thyroid eye disease, and one had an oculomotor nerve palsy (cranial nerve 3). Preoperatively, the average age was 57.7 years, best corrected visual acuity was 0.24 logarithm of the minimum angle of resolution (logMAR) in the right eye and 0.35 logMAR in the left eye, and deviation was 56.4 prism diopters (PD). The average postoperative residual deviation was 5.3 PD with an average follow-up time of 290 days. Four patients underwent reoperation, one of whom underwent a third surgery.

EOM disinsertion is an effective treatment in certain specific strabismus conditions. Patients who may benefit are those with a severe cranial nerve 6 palsy who cannot abduct the eye even to the midline and those with thyroid eye disease whose EOMs are so tight intraoperatively that even a small hook cannot be easily passed under the operative muscle adequately to perform a large recession technique. [.