Worldwide outcomes of nasal transposition of the split lateral rectus muscle for strabismus associated with 3rd-nerve palsy

A Comparison of Chemodnervation to Incisional Surgery for Acute, Acquired, Comitant Esotropia: An International Study

PURPOSE

To compare the efficacy of botulinum toxin injections to strabismus surgery in children with acute, acquired, comitant esotropia (ACE), and to investigate factors predicting success.

DESIGN

International, multi-center nonrandomized comparative study METHODS: Setting: Cloud-based survey.

STUDY POPULATION

Children aged 2 to 17 years who underwent a single surgical intervention for ACE.

INTERVENTIONS

Botulinum toxin injection ("chemodenervation" group) or strabismus surgery ("surgery" group).

MAIN OUTCOME MEASURES

Primary measure: success rate at 6 months in propensity-matched cohort, defined as total horizontal deviation of 10 prism diopters or less with evidence of binocular single vision. Secondary measure: Risk factors for poor outcomes in the full cohort.

RESULTS

Surgeons from 19 centers contributed. There were 74 patients in the chemodenervation group and 97 patients in the surgery group. In the propensity-matched data (n = 98), success rate was not significantly different at 6 months (70.2% vs 79.6%; P = .2) and 12 months (62.9% vs 77.8%; P = .2), but was significantly lower in the chemodenervation group at 24 months (52% vs 86.4%; P = .015). Irrespective of treatment modality, treatment delay was associated with lower success rates at 6 months, with median time from onset to intervention 4.5 months (interquartile range (IQR): 2.1, 6.7) in the success group and 7.7 months (IQR: 5.6, 10.1) in the failure group (P < .001).

CONCLUSIONS

In children with ACE, success rate after chemodenervation was similar to that of surgery for up to 12 months but lower at 24 months. Those with prompt intervention and no amblyopia had the most favorable outcomes, regardless of treatment modality.

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.

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.

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

PURPOSE

To determine success rate and complications associated with nasal transposition of the split lateral rectus muscle (NTSLR) for treating bilateral 3^rd-nerve palsy.

DESIGN

Retrospective, interventional case series METHODS: : Setting: International, multicenter registry Study population: All patients with bilateral 3^rd-nerve palsy treated with NTSLR.

OBSERVATION

Sensorimotor evaluations before and 6-months after unilateral or bilateral NTSLR.

OUTCOME MEASURES

Post-operative 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

Thirty-four 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 post-operative exotropia of 18 PD (IQR, 7-35 PD), and when performed bilaterally (35%) resulted in post-operative exotropia of 14 PD (IQR, 5-35 PD). Success was achieved in 50% of cases, intra-operative technical difficulties 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 (OR, 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 can increase the risk of vision-threatening complications, particularly serous choroidal effusion.