Efficacy of BT as a treatment for cranial nerve palsy in acute and chronic cases
Reviewed by Fiona Rowe

The authors performed a meta-analysis of all patients’ treatment with botulinum toxin (BT) for cranial nerve palsy (CNP) to determine the efficacy of BT in the treatment of CNP due to a variety of causes. The search identified 1129 articles from which 182 had full text evaluation, and 38 met inclusion criteria. These included 29 case series studies, six non-randomised controlled trials, one randomised controlled trial and two case reports. A total of 643 patients were included across all articles: mean age 41.9 ±14.2 years. Thirty-one studies reported sixth CNP, five fourth CNP and four third CNP. Acute CNP was reported in 19 studies and chronic in 11. Medial rectus BT was given for sixth CNP, lateral rectus BT for third CNP and inferior oblique or contralateral inferior rectus for fourth CNP. Mean number of injections was 1.3 for acute cases and 1.9 for chronic. Success rate overall was 79% for acute and 33% for chronic CNP. There were no significant differences for age, type of BT, angle of deviation, follow-up period, dose and number of injections, and unilateral vs bilateral cases. For sixth CNP, the best success was for diabetic cases and worst for those caused by tumour or vascular aetiology. Spontaneous recovery rates without BT injection were 52% for acute and 16% for chronic cases. The results indicate higher efficacy of BT over no treatment or spontaneous recovery rates for acute cases. There was no difference for chronic cases and therefore limited evidence for BT as a treatment option for chronic sixth CNP. Mean difference in angle of deviation from pre to post BT was higher for acute than chronic cases: -23.06 vs -14.44PD. Greatest improvement was seen within the first four months compared to the 4–12 month follow-up period. The authors conclude these patients need comprehensive assessment and follow-up to plot symptoms and requirement for BT injection.

Botulinum toxin injections for the treatment of third, fourth and sixth nerve palsy: a meta-analysis.
Khalili MR, Roshanshad A, Vardanjani HM.
JOURNAL OF PEDIATRIC OPHTHALMOLOGY AND STRABISMUS
2024;61(3):160–71.