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Studies of hemifacial spasm answer different questions. Some ask whether a treatment reduces spasms for a few months, others whether patients are free of spasm years after an operation, and others how a treatment affects daily life. Some compare treatments; most describe people who received one. The main sources are grouped below by the question they address.

Diagnosis and overview

Patient guides from the International Parkinson and Movement Disorder Society1 and Mayo Clinic2 describe the condition and its treatment. A 2025 review covers its causes, MRI assessment and management, including the difficulty of telling a relevant nerve-vessel contact from an incidental one3.

Botulinum toxin

A 2020 Cochrane review found no double-blind trials comparing toxin with placebo that met its criteria, while noting consistent improvement in observational studies4. A 2024 systematic review included 33 single-arm studies and two randomized trials of adding injections around the mouth when both groups received injections around the eye5. A 2025 randomized trial compared two toxin products over 12 weeks6. None of these compares toxin with surgery.

Microvascular decompression

A 2020 review pooled 6,249 patients from 39 studies and found 90.5% free of spasm at an average follow-up of about 15 months7. A 2022 review examined spasm returning after initially successful surgery8, and a 2024 review examined repeat operations9. Most of the surgical evidence comes from retrospective case series.

Reading the evidence

The figures for injections and for surgery measure different things. Improvement for a few months after an injection can't be compared directly with spasm freedom more than a year after an operation, because the patients, outcomes and follow-up all differ, and no trial has randomized patients between the two.

References

  1. International Parkinson and Movement Disorder Society. Hemifacial Spasm: Essential Facts for Patients. Webpage updated 2025; English handout ©2024. Source ↩
  2. Mayo Clinic Staff. Hemifacial spasm: Diagnosis and treatment. Updated 31 October 2025. Source ↩
  3. Jesuthasan A, Natalwala A, Davagnanam I, Saifee T, Zrinzo L. J Neurol. 2025;272:502. doi:10.1007/s00415-025-13220-y. Source ↩
  4. Duarte GS et al. Cochrane Database Syst Rev. 2020;11:CD004899. doi:10.1002/14651858.CD004899.pub3. Source ↩
  5. Wang B, Wei X, Qi H, Bao X, Hu M, Ma J. BMC Neurol. 2024;24:420. doi:10.1186/s12883-024-03883-x. Source ↩
  6. A 12-Week Prospective, Double-Blind, Multicenter, Randomized Study Comparing 100 Units of Abobotulinum Toxin Type A (Dysport) and 33.33 Units of Neubotulinum Toxin Type A (Neuronox) for the Treatment of Hemifacial Spasm. Toxins. 2025;17(4):173. doi:10.3390/toxins17040173. PMID:40278671. PubMed ↩
  7. Holste K, Sahyouni R, Teton Z, Chan AY, Englot DJ, Rolston JD. World Neurosurg. 2020;139:e383–e390. doi:10.1016/j.wneu.2020.04.001. Source ↩
  8. Menna G, Battistelli M, Rapisarda A, Izzo A, D’Ercole M, Olivi A, Montano N. Brain Sci. 2022;12(5):583. doi:10.3390/brainsci12050583. Source ↩
  9. Li Z, Zhang J, Wang N, Chen Y. Neurosurg Rev. 2024;47:804. doi:10.1007/s10143-024-03048-x. PubMed ↩