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Localizing Muscles for Botulinum Toxin Treatment of Focal Hand Dystonia

Published online by Cambridge University Press:  18 September 2015

C. Geenen
Affiliation:
Division of Neurology and EMG laboratory, The Toronto Hospital, and the University of Toronto, Toronto
E. Consky
Affiliation:
Division of Neurology and EMG laboratory, The Toronto Hospital, and the University of Toronto, Toronto
P. Ashby*
Affiliation:
Division of Neurology and EMG laboratory, The Toronto Hospital, and the University of Toronto, Toronto
*
The Toronto Hospital, 399 Bathurst Street, Edith Cavell 8-023, Toronto, Ontario, Canada M5T 2S8
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Abstract

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Background: There is currently no consensus on the best way to localize muscles in the forearm for botulinum toxin (BTX) injection. We devised a study to compare electromyography (EMG) with local stimulation through a cannula for localizing forearm muscles for botulinum toxin (BTX) injection, and for predicting the risk of unwanted weakness in non-target muscles. Methods: In 12 patients with focal hand dystonia a single “target” muscle, determined by clinical examination to contribute most to the dystonic hand posture, was selected for botulinum toxin injection. The patients were randomized into 2 treatment groups, one in which the target muscle was localized by recording the EMG signals during voluntary contractions (8 patients) and the other in which the target muscle was localized by local electrical stimulation (4 patients). The target muscle was then injected with a standardized dose of BTX. Results: At follow-up 3 weeks after BTX injection the target muscle was weakened in 7/12 patients (4/8 of the EMG group, and 3/4 of the stimulation group). Additional non-injected muscles, adjacent to the target muscle, were weakened in 5 of these 7 patients, presumably from diffusion of the toxin. Conclusions: Localization by stimulation is probably at least as good as EMG. Each technique has certain advantages. Weakness of “non-target” muscles was not consistently predicted by either EMG or stimulation suggesting that BTX diffuses farther than the volume conduction of EMG signals or the spread of effective stimulus current.

Résumé

Résumé

Localisation des muscles impliqués dans la dystonie focale de la main en vue du traitement par la toxine botulique. Introduction: Il n’y a pas actuellement de consensus quant à la meilleure façon de localiser les muscles de l’avant-bras pour l’injection de toxine botulique (TXB). Nous avons élaboré une étude pour comparer l’électromyographie avec la stimulation locale au moyen d’une canule pour la localisation des muscles de l’avant-bras dans le but d’injecter la TXB et pour prédire le risque de faiblesse inopportune de muscles qui n’étaient pas ciblés. Méthodes: Nous avons choisi un seul muscle cible, identifié par examen clinique comme contribuant le plus à la posture dystonique de la main, chez 12 patients souffrant d’une dystonie focale de la main. Les patients ont été randomisés en deux groupes, l’un chez qui le muscle cible était localisé par l’enregistrement de signaux EMG pendant des contractions volontaires (8 patients) et l’autre chez qui le muscle cible était localisé par stimulation électrique locale (4 patients). Une dose standard de TXB était ensuite injectée dans le muscle cible. Résultats: Au moment du suivi effectué 3 semaines après l’injection de TXB, le muscle cible était affaibli chez 7 patients sur 12 (4 sur 8 du groupe avec EMG et 3 sur 4 du groupe avec stimulation). D’autres muscles non injectés adjacents au muscle cible étaient affaiblis chez 5 de ces 7 patients, présumément par diffusion de la toxine. Conclusions: La localisation par stimulation est probablement aussi bonne que la localisation par EMG. Chaque technique a certains avantages. La faiblesse des muscles non ciblés n’était pas prédite de façon fiable par EMG ou par stimulation, ce qui suggère que la TXB diffuse plus loin que la conduction volumétrique des signaux EMG ou que la diffusion du courant d’excitation efficace.

Type
Original Articles
Copyright
Copyright © Canadian Neurological Sciences Federation 1996

References

1. Sheehy, MP., Marsden, CD. Writer’s cramp: a focal dystonia. Brain 1982; 105: 461480.CrossRefGoogle ScholarPubMed
2. Cohen, LG., Hallett, M. Hand cramps: clinical features and electromyographic patterns in a focal dystonia. Neurology 1988; 38: 10051012.Google Scholar
3. Koller, WC., Vetere-Overfield, B. Usefulness of a writing aid in writer’s cramp. Neurology 1989; 39: 149150.CrossRefGoogle ScholarPubMed
4. Lang, AET., Sheehy, MP., Marsden, CD. Acute anticholinergic action in focal dystonia. Adv Neurol 1983; 37: 193200.Google ScholarPubMed
5. Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Assessment: the clinical use of botulinum toxin A in treating neurologic disorders. Neurology 1990; 40: 13321336.Google Scholar
6. Karp, BI., Cole, RA., Cohen, LG., et al. Long term botulinum toxin treatment of focal hand dystonia. Neurology 1994; 44: 7076.CrossRefGoogle ScholarPubMed
7. Poungvarin, N. Writer’s cramp: the experience with botulinum toxin injections in 25 patients. J Med Assoc Thailand 1991; 74(5): 239247.Google Scholar
8. Rivest, J., Lees, AJ., Marsden, CD. Writer’s cramp: treatment with botulinum toxin injections. Mov Disord 1991; 6(1): 5559.Google Scholar
9. Yoshimura, DM., Aminoff, MJ., Olney, RK. Botulinum toxin therapy for limb dystonias. Neurology 1992; 42: 627630.Google Scholar
10. Karp, BI., Hallett, M. Botulinum toxin treatment of focal hand dystonia. In: Jankovic, J., Hallett, M., eds. Therapy with Botulinum Toxin. New York: Marcel Dekker, 1994; 299306.Google Scholar
11. Cohen, LG., Hallett, M., Geller, BD., Hochberg, F. Treatment of focal dystonias of the hand with botulinum toxin injections. J Neurol Neurosurg Psychiatry 1989; 52: 355363.Google Scholar
12. Borodic, GE., Joseph, M., Fay, L., Cozzolino, D., Ferrante, RJ. Botulinum A toxin for the treatment of spasmodic torticollis: dysphagia and regional toxin spread. Head and Neck 1990; 12: 392398.CrossRefGoogle ScholarPubMed
13. Borodic, GE., Ferrante, R., Pearce, LB., Smith, K. Histologic assessment of dose-related diffusion and muscle fibre response after therapeutic Botulinum A toxin injections. Mov Disord 1994; 9(1): 3139.Google Scholar