This retrospective study compared outcomes of conventional strabismus surgery with botulinum toxin injections for treatment of acute-onset comitant esotropia in children aged 2 to 10 years.
Study design
Forty-nine patients treated at a single center underwent either bilateral medial rectus muscle recession (“surgery group,” n=33) or botulinum toxin injected into the medial rectus muscles under general anesthesia without conjunctival incision (“chemodenervation group,” n=16). Each patient’s treatment modality was selected at the discretion of the treating physician. All patients had at least 6 months of follow-up.
Success was defined as final horizontal deviation of ≤10 D and evidence of binocular vision without retreatment.
Outcomes
At 6 months, botulinum appeared to be at least as effective as surgery, with statistically similar and numerically higher success (81% vs. 61%; P=0.20). Chemodenervation remained noninferior to surgery at month 18 (67% vs. 58%; P=0.73) in the 43 patients who completed extended follow-up.
Clinical significance
Chemodenervation offers a significant reduction in healthcare costs. Botulinum toxin injection payment averaged $874 per procedure compared with $2,783 for strabismus surgery.
In addition, the injections require significantly lower surgical times: the average duration of general anesthesia for botulinum toxin injection was 5 minutes compared with 71 minutes for surgery (P<0.001). A shorter surgical time minimizes the potential morbidity associated with general anesthesia in young children. Time in the post-anesthesia care unit was also much lower (37 vs. 83 minutes, P<0.001).
Finally, by avoiding muscle surgery, any subsequent strabismus procedures will more straightforward.
Limitations
This study is limited by its retrospective nature and small sample size. The long-term stability of botulinum toxin treatment is unknown, and prolonged follow-up is needed to demonstrate durability. Also notable, the time from esotropia onset to treatment was shorter in the chemodenervation group compared with the time-to-treatment in the surgery group, possibly resulting in more favorable results for the former, as some cases may have resolved spontaneously given more time.