Long-term experimental electric stimulation of denervated laryngeal muscles in dogs. Myopathologic findings
Herrmann, V.; Bergmann, K.
Zentralblatt für Allgemeine Pathologie U. Pathologische Anatomie 133(4): 337-350
1987
ISSN/ISBN: 0044-4030 PMID: 3425013 Document Number: 287853
The recurrent laryngeal nerve was transsected unilaterally and a device for electrical stimulation of the denervated muscles was implanted in 6 dogs. After 3 to 11 months the laryngeal muscles were obtained and histopathologically demonstrated a striking neurogenic pattern. In place of homogeneous muscle fiber atrophy, a patchwork of grouped fibre atrophy, compensational hypertrophy, fibre regeneration and reinnervation as well as muscle fibre type grouping were observed. Muscle fibre type distribution in the m. cricoarytenoideus posterior, m. vocalis and m. cricothyroideus was determined and compared between the normal and denervated sites. All muscles showed some changes in the fibre type distribution, including type grouping, but these were most pronounced in m. vocalis. The average fibre diameter decreased whereas fibre size variability increased. Mixed muscle fibre atrophy with compensatory hypertrophy of a single fibre type predominated. There was no evidence of disuse atrophy. The electrically stimulated muscles could be maintained at a reduced functional level throughout the study period.