Background: In this study, botulinum toxin A was used to secure the stabilization of muscle flaps without denervation atrophy.
Methods: Thirty adult female Wistar rats were divided into a control group (group I, n = 10), a denervation group (group II, n = 10), and a botulinum toxin A group (group III, n = 10). In all of the groups, pedicled pectoralis major muscle flaps were elevated from the sternal attachment on the right side. In the second group, muscle flaps were denervated by transsecting the pectoralis major nerve after flap elevation; in the third group, botulinum toxin A (1.4 U of Dysport; Ipsen, Maidenhead, United Kingdom) was injected into the prepared muscle flap before flap replacement. The distance between the medial side of the muscle and the midline was measured at 4 weeks. Histopathological examination was performed 10 weeks after the first operation. The diameter of the muscle fibers was measured, and the degree of atrophy in the muscle flaps was evaluated in all groups.
Results: Mean distances from the midline were statistically significantly different in all of the groups (p = 0.000, p < 0.01). There was a significant difference in muscle fiber diameter among the groups (p = 0.000, p < 0.01). Temporary denervation by botulinum toxin A and irreversible denervation with transsection of the motor nerve caused the reduced diameters of the muscle fibers. In addition, moderate to severe muscle atrophy in group II and mild to moderate muscle atrophy in group III were observed.
Conclusions: In the pedicled muscle flaps, botulinum toxin A can be used easily and reliably for stabilization. It was concluded that detachment of the muscle flap might be prevented and operative morbidity decreased using this method.