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.

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

PURPOSE: To determine the success rate and complications associated with nasal transposition of the split lateral rectus muscle (NTSLR) for treating bilateral 3rd-nerve palsy. DESIGN: Retrospective, interventional case series. METHODS: An international, multicenter registry was used for the study. The study population was all patients with bilateral 3rd-nerve palsy treated with NTSLR. Sensorimotor evaluations were conducted before and 6 months after unilateral or bilateral NTSLR. Outcome measures were postoperative horizontal alignment ≤15 prism diopters (PD), intraoperative technical difficulties, and vision-threatening complications. The association of patient demographics and surgical technique with each outcome was analyzed using multivariable logistic regression. RESULTS: A total of 34 patients were included, with a median age of 46 years (interquartile range [IQR] = 25-54 years) at surgery. The most common etiologies were ischemic (29%), neoplastic (15%), and congenital (12%). NTSLR performed unilaterally with alternative surgery on the opposite eye (65%) resulted in a median postoperative exotropia of 18 PD (IQR = 7-35 PD), and when performed bilaterally (35%) resulted in postoperative exotropia of 14 PD (IQR = 5-35 PD). Success was achieved in 50% of cases, intraoperative technical difficulties were reported in 18%, and vision-threatening complications occurred in 21%. Attachment of the lateral rectus muscle ≥10 mm posterior to the medial rectus insertion was associated with increased vision-threatening complications (odds ratio = 9.0; 95% CI = 1.3-99). CONCLUSIONS: NTSLR can address the large-angle exotropia associated with bilateral 3rd-nerve palsy. Surgeons should be aware that posterior placement of the lateral rectus muscle may increase the risk of vision-threatening complications, particularly serous choroidal effusion.