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The clinical utility of botulinum toxin injections targeted at the motor endplate zone in cervical dystonia
Author(s) -
Delnooz C. C. S.,
Veugen L. C.,
Pasman J. W.,
Lapatki B. G.,
Dijk J. P.,
Warrenburg B. P. C.
Publication year - 2014
Publication title -
european journal of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 124
eISSN - 1468-1331
pISSN - 1351-5101
DOI - 10.1111/ene.12517
Subject(s) - cervical dystonia , medicine , botulinum toxin , spasmodic torticollis , sternocleidomastoid muscle , electromyography , anesthesia , dystonia , clostridium botulinum , botulism , surgery , torticollis , physical medicine and rehabilitation , toxin , biochemistry , chemistry , psychiatry , biology , genetics
Background and purpose Cervical dystonia ( CD ) patients usually receive repeated botulinum neurotoxin (Bo NT ) injections. The aims of this study were to evaluate the feasibility of motor endplate zone ( MEZ ) detection of relevant cervical muscles in CD patients receiving chronic Bo NT treatment and to compare the treatment effect of half‐dosed, endplate‐targeted injections to standard Bo NT injections. Methods In study 1, high‐density surface electromyography (HD‐sEMG) was recorded from the sternocleidomastoid ( SCM ) and splenius capitis ( SC ) muscles in 18 CD patients with ongoing Bo NT treatment, by which the location of the MEZ was determined. In study 2, nine additional patients with rotational‐type CD participated in a treatment effect study where they received either half of their regular Bo NT dose through endplate‐targeted injections or their normal Bo NT dose through standard injections (crossover design). Dystonia severity was recorded before and 4 weeks after each treatment session ( Toronto Western Spasmodic Torticollis Rating Scale severity subscore). Results In the SCM muscle the MEZ was located at the lower border of the superior third part of the muscle, and in the SC muscle at half muscle length. Endplate‐targeted, half‐dosed Bo NT injection resulted in a similar treatment effect to injecting the full dose in the standard technique. Conclusions Half‐dosed, endplate‐targeted BoNT injections lead to a similar treatment effect to the standard BoNT injection protocol. MEZ detection confronts the clinician with some technical challenges, such as the ability of accurate and technically optimal placement of the electrode grid and correct interpretation of the HD‐sEMG signal.