Clinical outcomes of botulinum toxin injection in patients with cerebral palsy and esotropia

Factors Affecting the Efficacy of Botulinum Toxin Injection in the Treatment of Infantile and Partially Accommodative Esotropia

PURPOSE

We aimed to investigate the effect of botulinum toxin (BT) injection on the treatment of infantile and partially accommodative esotropia (PAET).

METHODS

This retrospective cohort study included patients who received BT injections for infantile and PAET between January 2015 and December 2018. Treatment was considered successful if orthotropia, consecutive exotropia, or esotropia within 10 prism diopters (PD) was achieved.

RESULTS

The overall success rate was 47.4%, with a mean follow-up period of 27.8 months in 403 children. BT treatment was considered successful in 37.1% of cases of infantile esotropia and 53.1% of cases of partially accommodative esotropia. The average deviation angle before starting treatment was 35.5 ± 13.9 PD. Side effects 1 week after BT injections included transient overcorrection (63.8%) and transient ptosis (41.7%). There were no significant differences in the success rates between the different doses of BT (P = 0.69). The angle of deviation at presentation was significantly associated with the success rate of BT injection (failed group, mean: 38.1 ± 15.3 PD vs. success group, mean: 32.6 ± 11.6 PD; P < 0.001). Other factors associated with higher success rates were overcorrection at 1 week and PAET, while multivariate logistic regression analysis showed that a smaller angle of deviation and overcorrection (1 week after injection) were associated with a higher success rate.

CONCLUSION

A smaller angle of deviation and transient overcorrection were associated with a higher success rate, and no significant difference was observed in the success rates of different BT doses.

Success rates of botulinum toxin in different types of strabismus and dose effect

OBJECTIVE

To determine the effect of botulinum toxin in different types of strabismus and analyze its dose effect.

DESIGN

This was an interventional clinical study performed in a tertiary care university hospital.

METHODS

Eighty six patients treated with botulinum toxin for strabismus were included. Main outcome measures involved success of botulinum toxin, alignment change per unit of toxin, and dose effect on complications and outcomes.

RESULTS

Success rates were 31% for infantile esotropia, 25% for partially accommodative esotropia, 61.5% for residual esotropia, 25% for third cranial nerve paralysis, 13.3% for sixth cranial nerve paralysis, 75% for Duane retraction syndrome, and 38.5% for nonaccomodative esotropia. Improvement in deviation size after botulinum toxin treatment was significant in patients with infantile esotropia (p = 0.001), residual esotropia (p = 0.001), and nonaccomodative esotropia (p = 0.03). Mean deviation change per 1 unit of toxin was 2.7 ± 2.4 prism diopters (PD) with a single injection and 2.1 ± 1.9 PD with multiple injections. A 3.32 PD of early deviation change with botulinum toxin corrected 1 PD of final deviation. Success rate was not correlated with age (r = 0.040, p = 0.8), sex (r = -0.083, p = 0.6), mean dose (r = -0.149, p = 0.35), or total dose (r = 0.165, p = 0.29) but was significantly correlated with deviation size (β = -0.077, p = 0.0001). Complications were not associated with the dose of botulinum toxin (p > 0.05).

CONCLUSIONS

Botulinum toxin has variable outcomes in different types of strabismus. Still, it reduces the deviation size in most patients, thus allowing for a smaller amount of subsequent muscle surgery. Early overcorrection is a more powerfull indicator of better outcome than postinjection duction deficit.

Short-term outcome of botulinum neurotoxin A injection with or without sodium hyaluronate in the treatment of infantile esotropia-a prospective interventional study

Purpose

To compare the short-term outcome of botulinum neurotoxin A (BoNT-A) with or without sodium hyaluronate in the treatment of infantile esotropia (IE).

Methods

In this tertiary care hospital-based prospective, interventional, non-randomized study on infants with IE below one year of age, 25 cases were enrolled in the sodium hyaluronate (SH) group to receive 2.5 U BoNT-A injection combined with SH in each medial rectus muscle (MR). Thirty patients were enrolled in the control group to receive 2.5 U BoNT-A injection with normal saline in each MR. The change in mean primary ocular deviation (POD) and complications were assessed at 2 weeks, 1 month, 3 months, and 6 months post injection. Mann-Whitney U test was used for non-parametric unpaired data. Chi-square test and Fisher's exact test were used to test for the strength of the association between the two categorical variables.

Results

Satisfactory ocular alignment was achieved in 76% in SH group and 73% in the control group (P value = 0.80). While the change in mean POD was comparable (29.2 prism diopters [PD] vs 29.3 PD; P value = 0.65), the complication rates were significantly lesser in SH (16% vs 33.3%; P value = 0.14).

Conclusion

BoNT-A combined with SH is equally effective with lesser complications as compared to botulinum toxin alone in the treatment of IE.

Comparison of the Efficiency of the Botulinum Toxin for the Treatment of Esotropia in Children with and without Neurological Disease and/or Prematurity

OBJECTIVE

To compare the effect of botulinum toxin injection for the management of esotropia in patients with and without neurological disease and/or prematurity.

METHODS

A single-center, retrospective, nonrandomized controlled study was performed on botulinum toxin in 87 children divided into two groups: study group of esotropia in 56 children with neurological disease and/or prematurity and, control group of 31 healthy children with infantile esotropia. All patients were followed for at least 24 months after injection. Success was defined as motor alignment with 10^Δ of orthotropia after single bilateral botulinum injection.

RESULTS

Mean age at treatment was similar in both groups (15.5 vs 14.8 months; p = .555). Mean pretreatment deviation was similar in both groups (50.8^Δ vs 50^Δ; p = .855). The success rate was better in the control group (61.2% vs 51.7%, p = .265) at 24 months after injection, but the change in the mean angle of deviation was not statistically significant between the groups at 12 and 24 months after injection (p = .264 and p = .547, respectively). Multivariate regression analysis showed that pretreatment angle of deviation and presence of retinopathy of prematurity were significant predictors at 12 months after injection (p = .0001 and p = .004, respectively), while pretreatment angle of deviation was found to be a predictor at 24 months after injection (p = .0001).

CONCLUSIONS

Decreased angle of deviation and absence of retinopathy of prematurity were associated with a better result. There was no difference in motor alignment of esotropia in children with and without neurological disease and/or prematurity. In these patients, botulinum injection may be used as an alternative to surgery.

The resurgence of botulinum toxin injection for strabismus in children

PURPOSE OF REVIEW

The present review discusses recent advances in the use of botulinum toxin for the management of strabismus in children.

RECENT FINDINGS

Botulinum toxin injection produces similar results compared to surgery for certain subtypes of strabismus, especially acute onset esotropia. It may be more effective in many subtypes of esotropia where surgery has been less reliable, including partially accommodative esotropia, esotropia associated with cerebral palsy, and thyroid eye disease.

SUMMARY

Small retrospective studies have demonstrated the efficacy of botulinum toxin in the treatment of many types of pediatric strabismus, providing some guidance for clinicians to determine which patients would benefit most from this intervention. Although administration of botulinum toxin is generally accepted as a reasonable option in select cases, many strabismus surgeons have not fully embraced the treatment, in part because of perceived disadvantages compared to surgery and difficulty in identifying subsets with the highest potential for therapeutic success. A recent study compared the administration of botulinum toxin in children with acute-onset esotropia to surgical correction and found botulinum toxin had a statistically equal success rate, but with the advantage of significantly less time under general anesthesia. In addition, botulinum toxin has been recently tried in patients with partially accommodative esotropia, esotropia associated with cerebral palsy, cyclic esotropia, and in patients with thyroid eye disease. The present review will discuss current clinical recommendations based on recent studies on the use of botulinum toxin in children with strabismus.

Botulinum therapy in post-traumatic strabismus and diplopia treatment

In the article, a first-hand experience of paretic post-traumatic strabismus treatment using botulinum toxin type A is presented. Analysis of strabismus angle alteration and of diplopia severity has been performed.