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Authors Inagi K, Connor NP, Schultz E, Ford CN, Cook CH, Heisey DM
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Journal Otolaryngol Head Neck Surg Volume: 120 Issue: 6 Pages: 876-83
Publish Date 1999 Jun
PubMed ID 10352443

This study examined muscle fiber-type alterations after single or multiple botulinum toxin (BT) injections to better understand possible morphologic changes induced by therapeutic BT injections in patients with spasmodic dysphonia. Muscle fiber staining was accomplished in rat intrinsic laryngeal muscles with antibodies to specific myosin heavy chains. Results indicated that the typical baseline distributions of type II muscle fibers (ie, types IIa, IIb, IIx, and IIL) were altered by BT injection, while no change was observed in type I fibers. Embryonic fibers were observed only along the needle insertion site at 7 days post BT injection. Although inferences from these animal data to human neuromuscular function must be made with caution, our findings provide insight into the possible cellular and molecular changes characterizing BT-injected muscles. Copyright © 2017 The Board of Regents of the University of Wisconsin System