Supramaximal Horizontal Rectus Recession-Resection Surgery for Complete Unilateral Abducens Nerve Palsy.

Purpose: To review the surgical procedures and outcomes of supramaximal horizontal rectus recession-resection surgery for abduction deficiency and esotropia resulting from complete unilateral abducens nerve palsy. Methods: A total of 36 consecutive cases diagnosed as complete abducens nerve palsy, receiving supramaximal medial rectus recession (8.5 ± 1.4 mm, range: 6-10) combined with a supramaximal lateral rectus resection (11.1 ± 1.7 mm, range: 8-14) as performed over the period from 2017 to 2020, were reviewed retrospectively. All surgeries were performed by a single surgeon. Pre- and post-operative ocular motility, ocular alignment, forced duction test, binocular vision, abnormal head posture, and surgical complications were assessed. Results: Of these 36 cases, 23 (63.8%) were followed up for greater than 2 months (Mean ± SD = 8.4 ± 6.0, range: 2-24) after surgery and the collected data was presented. Mean ± SD age of these patients was 41.7 ± 14.4 (range: 12-67) years with 73.9% being female. Trauma (52.2%, 12/23) and cerebral lesions (21.7%, 5/23) were the primary etiologies for this condition. Esodeviation in primary position improved from 55.5 ± 27.2 prism diopters (PD) (range: +25 to +123) to 0.04 ± 7.3 PD (range: -18 to +12) as assessed on their last visit. Pre-operative abduction deficits of -5.6 ± 1.0 (range: -8 to -4) reduced to -2.4 ± 1.4 (range: -4 to 0) post-operatively. The mean dose-effect coefficient of 2.80 ± 1.20 PD/mm (range: 1.07-6.05) was positively correlated with pre-operative esodeviation. Rates of overcorrection and ortho were 69.6 and 26.1%, respectively, on the first day after surgery, while on their last visit the respective levels were 4.3 and 82.6%. Conclusion: Supramaximal horizontal rectus recession-resection surgery is an effective treatment method for complete abduction deficiency. The dose-effect was positively correlated with pre-operative esodeviation. Overcorrection on the first day post-operatively is required for a long-term satisfactory surgical outcome.