Effects of denervation on posterior cricoarytenoid muscle physiology and histochemistry.
The effects of chronic posterior cricoarytenoid muscle denervation were assessed at 3 and 7 months in 26 animals following resection of 10 cm of recurrent laryngeal nerve with stump ligation. The physiology of denervation was characterized by a decrease in contraction strength and an increase in contraction time. The reduction in contraction strength reflected the loss in muscle weight and atrophic changes in fiber density and diameter. A change in muscle composition occurred because of the increased susceptibility of fast-twitch (type 2) fibers to degeneration. However, the compositional change alone could not account for the slowing of muscle contraction. Muscle fibrosis was negligible at 3 months, but encompassed one third of the fiber population by 7 months. In view of the irreversible nature of fibrosis, this study suggested that clinical intervention to rescue denervated posterior cricoarytenoid muscle fibers should be delayed no longer than 7 months to improve the chances for full recovery.
Zealear
D L
DL
Department of Otolaryngology-Head and Neck Surgery, School of Medicine, Vanderbilt University, Nashville, Tennessee 37232.
Hamdan
A L
AL
Rainey
C L
CL
D000818:Animals; D004285:Dogs; D007821:Laryngeal Muscles / Q000737:chemistry / Q000294:innervation / Q000503:physiopathology*; D009119:Muscle Contraction / Q000502:physiology; D009121:Muscle Denervation; D018485:Muscle Fibers, Skeletal; D009133:Muscular Atrophy / Q000503:physiopathology*