Botulinum toxin as an adjunct to monocular recession-resection surgery for large-angle sensory strabismus

Dose-Effect Relationship of Botulinum Toxin Type A in the Management of Strabismus: A Review

Botulinum toxin type A (BTXA) is a well-accepted non-surgical therapy for strabismus. However, its dose and technique vary widely. We reviewed published evidence on the dose effect of BTXA in treating various types of strabismus. Articles on BTXA therapy outcomes were reviewed to study doses and brands of BTXA used and their efficacy for specific types of strabismus. Researchers indicated that greater dosages may be used safely without increasing the risk of complications. The review suggested a positive dose-response relationship of BTX to success but with a higher risk of complications. No single dose of BTX could be recommended for strabismus management.

Botulinum Toxin A Augmentation of Strabismus Surgery for Large-Angle Strabismus: A Retrospective Case Series and Literature Review

PURPOSE

To report the results of botulinum toxin A (BTA)-augmented bilateral recession or monocular recession/resection surgery in a case series of patients with large-angle strabismus and review the relevant literature.

METHODS

This retrospective study reviewed the medical records of 24 patients treated with BTA-augmented strabismus surgery for large-angle horizontal strabismus (55 prism diopters or greater) with a minimum 6-month follow-up. Patients underwent unilateral recession-resection or bilateral rectus muscle recession surgery with intraoperative BTA injection into the recessed muscle(s). Main outcome measures were postoperative angle of deviation and success rate, defined as a final deviation of 10 prism diopters or less.

RESULTS

Of 24 patients (20 esotropia, 4 exotropia), the mean age was 9.2 years (range: 1 to 64 years). Mean preoperative deviation was 61.2 prism diopters for esotropia and 66.2 prism diopters for exotropia. Mean final postoperative deviation was 6.6 prism diopters for esotropia and 14.5 prism diopters for exotropia. Successful outcomes were achieved in 75% of patients with esotropia and 50% of patients with exotropia.

CONCLUSIONS

BTA augmentation of conventional strabismus surgery dosages is a promising approach for managing large-angle strabismus, particularly esotropia. Optimal patient selection and follow-up are needed to maximize surgical success rates. [J Pediatr Ophthalmol Strabismus. 20XX;X(X):XXX-XXX.].

Botulinum toxin augmented surgery versus conventional surgery in the management of large-angle concomitant esotropia: A randomized clinical trial

BACKGROUND

The surgical management of large-angle concomitant esotropia is challenging with high reoperation rates. This study aims to assess the effectiveness and safety of intraoperative botulinum toxin A (BTA) augmentation compared to surgery alone in large angle concomitant esotropia.

MATERIALS AND METHODS

This is a prospective randomized interventional study. Patients with large angle concomitant esotropia (≥55 prism diopter [PD]) were randomly allocated to either surgery only (Group I) or BTA augmented surgery (Group II). The surgical effect in PD/mm was calculated and compared between the study groups at all follow up intervals. Treatment was considered successful if the patients had orthotropia ± 10 PD at their final examinations.

RESULTS

A total of 23 patients were included in the study, 11 in Group I and 12 in group II. The surgical effect was significantly greater in Group II compared to Group I at all follow up durations. The 1-year surgical effect was 32.5% greater in Group II compared to Group I (5.99 ± 0.69 vs. 4.52 ± 0.91 PD/mm, respectively, P = 0.001). The success rate was greater for Group II compared to Group I (75% vs. 63.64%, respectively), but this difference was not statistically significant (P = 0.901).

CONCLUSION

Botulinum toxin augmented surgery is a good alternative to surgery alone in the treatment of large angle concomitant esotropia. BTA injection exerts a significant augmentation effect on medial rectus muscle recessions.

Botulinum Toxin as an Adjunct to Bilateral Medial Rectus Recessions for Large Angle of Esotropia in High Myopic Patients: A Case Report

Botulinum toxin injection adjunct to bilateral medial rectus recession is a documented procedure for correcting the large angle of infantile esotropia. A 9-year-old boy presented with a large angle of esotropia (80 PD) and high myopia. He underwent bilateral medial rectus recession with an adjunct botulinum toxin injection. Six months after the procedure, the patient had an esotropia of < 10 PD. Maximum bilateral medial rectus recession (BMR) with augmented botulinum toxin injection can be an effective procedure for large-angle acquired esotropia. This is helpful in avoiding an initial three-muscle operation.

Supramaximal Recession and Resection Surgery in Large-Angle Strabismus: Outcomes of Large Interventional Case Series Exotropia and Esotropia

Purpose:

To assess the postoperative surgical outcomes and the changes in deviation in patients treated by supramaximal recession and resection (R&R) of rectus muscles to correct the large-angle exotropia and esotropia.

Methods:

This study was a prospective interventional case series, and patients with esotropia of ≥65 prism diopter (PD) or exotropia of ≥60 PD who had undergone supermaximal R&R in non-fixating eye with lower vision in unilateral strabismus or bilateral medial rectus (BMR) recession up to 8.5 mm for esotropia and bilateral lateral rectus (BLR) recession up to 12.5 mm for exotropia in bilateral strabismus were enrolled. Successful results were achieved if postoperation deviation was <10 PD for esotropia and <15 PD for exotropia during their final examinations.

Results:

A total of 131 cases (48 patients with esotropia and 83 patients with exotropia) were included. The mean ages of the patients with esotropia and exotropia were 16.83 ± 15.06 and 23.19 ± 11.29 years, respectively. The mean preoperative esodeviations for bilateral and unilateral surgeries were 69.5 ± 6.5 and 80.7 ± 10.3, respectively, and these values for bilateral and unilateral exodeviations surgeries were 67.3 ± 7.6 and 74.2 ± 12.1, respectively. The overall successful outcomes were achieved in 50% of the esotropic patients and 79.5% of the exotropic patients. At final follow-up examination, no patient had diplopia on lateral gazes.

Conclusion:

Based on our surgical results, it is possible to consider monocular recession-resection surgery in non-fixating eye (with poor vision) or BLR and BMR recession in both eyes as a viable option for surgical treatment of large angles deviations.

Using Botulinum Toxin A as an Adjunct in the Surgery of Large-Angle Sensory Exotropia and Abducens Nerve Palsy

Regarding the review article by Escuder AG, Hunter DG, entitled "The Role of Botulinum Toxin in the Treatment of Strabismus" Seminars in Ophthalmology. 2019;34(4): 198-204, we cannot agree with you more with your point of view about the dosage preparation for botulinum toxin A (BTA) in the strabismus surgery. Moreover, we also included a case series that used BTA as an adjunct in the surgery for large-angle sensory exotropia and abducens nerve palsy.

The Use of Botulinum Toxin in Strabismus Treatment

There is a long and extensive experience with the use of Botulinum Toxin type A (BoNT-A) injection in the treatment of different types of strabismus and oculomotor palsies. The frequency of its use varies depending on the country and institution. It is a short procedure, may reduce general anesthesia exposure, causes minimal scarring compared to surgery, and can be proposed as an early treatment in unstable strabismus. Over many years, the experience of using BoNT-A indications has been refined and new applications have been reported. The use of BoNT-A in the postoperative period, after strabismus surgery or during surgery, can also be beneficial.