The efficacy of botulinum toxin type A treatment and surgery for acute acquired comitant esotropia

Abstract

AimTo compare the long-term efficiency of botulinum toxin type A (BTXA) injection and surgery on acute acquired comitant esotropia (AACE).MethodsThis retrospective study enrolled patients with AACE from January 2020 to August 2022. The horizontal angle of deviation pre- and post-treatment was measured. Deviations in BTXA and surgical treatment were compared. The BTXA group was divided into adequate treatment (AT) and inadequate treatment (inAT) subgroup based on the deviation of no more than 4 prism diopters (at near and distance) or temporary exotropia at the 2 week follow-up. The two subgroups were compared to determine the long-term efficacy of BTXA treatment.ResultsNinety-two patients with AACE were included. Follow-up was 6 months. The deviations of the surgery and BTXA group were significantly smaller at the 6 month follow-up than at pre-treatment (p < 0.001). The deviation before treatment in the surgery group was larger than in the BTXA groups (p < 0.001) but smaller at the 6 month follow-up (p < 0.001). The deviation was similar in the AT-BTXA and inAT-BTXA subgroups before treatment (p = 0.322 for distance and p = 0.051 for near) but smaller in the AT-BTXA subgroup at 6 month follow-up (p < 0.001 for near and distance).ConclusionSurgery and BTXA successfully treat AACE. Surgery has a more precise and lasting therapeutic effect than BTXA. AACE patients adequately treated with BTXA and with deviations of no more than 4 prism diopters at 2 weeks follow-up had better outcomes.

Advances in the diagnosis and treatment of acute acquired comitant esotropia

“…Botulinum toxin therapy involves injecting botulinum toxin into the medial rectus muscle to weaken its strength and thus improve the condition of strabismus. There are several methods for injecting BTXA, including microinjection through a small conjunctival incision [ 79 , 80 ], electromyography(EMG) guided injection without a conjunctival incision [ 81 ], and direct conjunctival injection without an incision or EMG [ 79 , 82 – 87 ]. With advantages like minimal invasiveness, simplicity, low cost, and rapid recovery, BTXA treatment is still a feasible choice for patients with minor strabismus angles and those who urgently require treatment with an unstable strabismus degree for less than six months.…”

“…Studies show that the residual angle of deviation and success rate six months after botulinum toxin treatment are related to the angle of deviation two weeks into the treatment. Thus, the deviation angle at two weeks can serve as an indicator of early treatment effectiveness, predicting long-term efficacy [ 82 ]. Botulinum toxin treatment is dose-dependent, so selecting the appropriate injection dose based on the angle of strabismus can enhance the success rate of the treatment.…”

“…We have compiled a table summarizing research on the use of botulinum toxin in AACE, with studies meeting the following criteria: published within the last decade, at least six months follow-up, and a single botulinum toxin injection. The aim is to investigate the effectiveness and feasibility of botulinum toxin in the management of AACE from a quantitative perspective (see Table 3 ) [ 79 , 80 , 82 – 87 ].…”

“…of pts Age(years) Type. BX Dose(IU) Methods Follow-up(mos) Pre-injection angle(PD) Post-injection angle(PD) Definition of success Success rates Complications Xu et al [ 79 ] 29 14.2 ± 7.4[4–34] BTXA (Hengli, China) 15-20PD 2.5U(Uni) 20-40PD 5.0U(Bi) 40-60PD 6.0U(Bi) S2 6 Distance 40.2 ± 17.7 near 38.4 ± 18.9 Distance 3.0 ± 5.9 near 0.6 ± 4.1 Deviation ≤ 10PD evidence of binocular single vision 86.2%(25/29) Transient exotropia 24%(7/29) transient hypertropia 14%(4/29) transient ptosis 10%(3/29) Li et al [ 82 ] 51 23.9[6–50] BTXA (Hengli, China) 10-25P 3.0U 26-35P 3.5U > 35PD 4.0U S1 6 Distance 20[15–30] near 18[12.5–25] Distance 6[4–14] near 4 [2–8] Deviation ≤ 8PD diplopia disappeared 58.8% (30/51) Transient ptosis transient exotropia Wan et al [ 83 ] 16 3.1[2.2–9.3] BOTOX (Allergan, US) 5.0U(Bi) 1 patients 45PD 3.5U(Bi) 1 patients 40PD 4.0U(Bi) (1U/0.01ml) S1 6 35[10–55] 0 [0–18] Deviation ≤ 10PD evidence of binocular single vision no need for retreatment 81%(13/16) Transient ptosis 50%(8/16) transient exotropia 56%(9/16) …”