Periosteal fixation of the medial and lateral recti for large-angle incomitant exotropia.

Abstract

To describe the evolution of a surgical technique for the correction of large-angle incomitant exodeviations. Retrospective review of an interventional case series from 2005 to 2019 in a single centre, with analysis of surgical procedure, prism diopter (PD) deviations and complications. Thirty-one patients underwent surgery at an average age of 42years (range 4-75years) for minimal medial rectus function, mostly from oculomotor nerve palsy (23/31; 74%). The mean pre-operative exodeviation was 75 PD (range 30-200PD). Sixteen patients (52%) had undergone previous strabismus surgery. Thirty-eight operations were performed in which the medial rectus insertion was anchored to the periosteum of the posterior lacrimal crest via a retrocaruncular transconjunctival approach. The ipsilateral lateral rectus (LR) was disinserted and fixed to lateral orbital tissue in 29/38 (76%) operations, injected with botulinum toxin in 5, recessed in 2 and had already undergone maximal LR recession in 2. In all but the first 8 operations, temporary limbal sutures were passed through the eyelids to maximally adduct the globe post-operatively. At last follow-up (mean 24months; range 2-130), the mean reduction in exodeviation was 49PD (range 10-80) and overall residual deviation was 26PD (range 80PD base-in to 14PD base-out). The 5 LR toxin procedures had a mean reduction of 22PD (range 10-40). Seven patients had persistent diplopia, one a transient corneal erosion and one caruncle suture exposure 4years after surgery. Large-angle exodeviations can be markedly improved by bi-rectus fixation. This approach is both safe and effective and can be performed in complex patients with multiple previous procedures.