Preseptal and Pretarsal Botulinum Toxin Injection in Hemifacial Spasm and Blepharospasm: A 10-Year Comparative Study.

Purpose: Preseptal and pretarsal botulinum toxin injections are approved for treatment of hemifacial spasm and blepharospasm. However, the long-term data is limited. We compared the efficacy, safety, and costs between preseptal and pretarsal injection in hemifacial spasm and blepharospasm.

Patients and methods: The data were retrieved between 2011 and 2021. Consecutive hemifacial spasm and blepharospasm botulinum toxin patients were categorized as preseptal or pretarsal. Study outcomes were the difference in pre-and post-treatment modified Jankovic scale, self-reporting scales, time-related treatment, safety, and cost.

Results: Of 152 botulinum toxin-injected patients, 117 (77.0%) patients had hemifacial spasm and 35 (33.0%) patients had blepharospasm. Analysis included data pertinent to 1665 injections in hemifacial spasm (920 preseptal and 745 pretarsal) and 527 injections in blepharospasm (210 preseptal and 317 pretarsal). The difference between pre-and post-treatment modified Jankovic scale was lower in the preseptal group than in the pretarsal group in both hemifacial spasm and blepharospasm (1.5±0.8 vs 1.8±0.6, P-value <0.001 and 1.8±0.8 vs 3.1±0.9, P-value <0.001). There was no difference in duration of maximum response in hemifacial spasm between groups, while the blepharospasm with preseptal had a longer duration than blepharospasm with pretarsal. The preseptal injection was associated with more adverse events overall than the pretarsal (9.4% vs 5.2%, P-value <0.001). The total dose and cost per session in the preseptal group is lower for onabotulinum toxin but higher for abobotulinum toxin.

Conclusion: Pretarsal injections reduced symptom severity with fewer side effects. Further studies on the pharmacoeconomics of both techniques are required.