Aberrant regeneration in an international registry of patients with 3rd-nerve palsy

To describe the patterns of pre-operative aberrant regeneration and motility outcomes reported in an international registry of patients with 3^rd-nerve palsy treated with nasal transposition of the split lateral rectus muscle (NTSLR).

This cross-sectional study used data from an international, multicentre registry of patients with 3^rd-nerve palsy treated with NTSLR. Patients with aberrant regeneration were identified, and patterns of innervation described. Demographics and postoperative success defined as horizontal alignment ≤15 PD were compared based on the presence, and type, of aberrant regeneration using Wilcoxon rank sum and Fisher's exact tests.

Aberrant regeneration was reported in 16% (21/129) of patients. Age at diagnosis, sex, and aetiology of palsy were not significantly associated with aberrant regeneration. Abnormal movements were triggered by adduction in 52% (11/21), infraduction in 23% (5/21), and supraduction in 23% (5/21) of cases. Presentation patterns involved rectus muscle innervation in 29% (6/21) and levator muscle innervation in 71% (15/21) of cases. Although patients with aberrant regeneration had similar probability of success in comparison to those without following NTLSR (76% vs. 69%, p = 0.5), those with abnormal innervation of a rectus muscle had a lower success rate than those with abnormal innervation of the levator palpebrae superioris muscle (17% vs. 93%; p = 0.002).

Successful treatment of a 3^rd nerve palsy with NTSLR was not influenced by aberrant regeneration involving the levator muscle. Alternative surgical interventions should be considered when aberrant regeneration alters rectus muscle function given its adverse impact on motor outcomes with NTSLR.