Nasal Transposition of the Split Lateral Rectus Muscle for Strabismus Associated with Bilateral 3rd-Nerve Palsy

Extraocular muscle ductions following nasal transposition of the split lateral rectus muscle

OBJECTIVE

To quantify changes in ductions following nasal transposition of the split lateral rectus muscle (NTSLR) for treating third nerve palsy.

DESIGN

Retrospective cohort study.

PARTICIPANTS

A single eye from each patient with third nerve palsy treated with NTSLR with ocular motility measurements.

METHODS

Observation of changes in pre- and postoperative ductions. Outcome measures including patient demographic and surgical factors associated with the ability to adduct beyond the midline after NTSLR were evaluated using multivariable logistic regression.

RESULTS

A total of 116 patients met the inclusion criteria for this study. The NTSLR significantly decreased abduction (median of 0 limitation [interquartile range (IQR), 0-0] prior to surgery to -4 [IQR, -4 to -3] after NTSLR; p < 0.001), with a corresponding improvement in adduction (median, -5 [IQR, -5 to -4] prior to surgery to -4 [IQR, -4 to -3] after NTSLR; p < 0.001). There was no change in median supraduction or infraduction after NTSLR (p > 0.05). The ability to adduct beyond the midline after NTSLR was demonstrated in 42% of patients. Although not statistically significant, a trend toward a postoperative ability to adduct beyond the midline was seen in patients who had concurrent superior oblique muscle tenotomy (odds ratio [OR] = 5.08; 95% CI, 0.91-40.9) or who were designated with partial rather than complete third nerve palsy (OR = 2.29; 95% CI, 0.82-6.70).

CONCLUSIONS

NTSLR improves the horizontal midline positioning of eyes with third nerve palsy. Most eyes lose the ability to abduct, but some regain a modest ability to adduct while vertical ductions remain unchanged.

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

BACKGROUND/AIMS

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

METHODS

This cross-sectional study used data from an international, multicentre registry of patients with 3rd-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.

RESULTS

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).

CONCLUSION

Successful treatment of a 3rd 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.

Strategies for managing strabismus from oculomotor nerve palsy

Addressing ocular misalignment secondary to partial and complete oculomotor nerve palsy presents a special challenge to the strabismus surgeon, particularly when treating patients with binocular diplopia. We review the reported surgical options and, through illustrative cases, provide our own perspective on managing this disorder.