Quantitative assessment of laryngeal muscle morphology after recurrent laryngeal nerve injury: right vs. left differences.
OBJECTIVE
Reports of laryngeal response to denervation are inconsistent. Some document atrophy and fibrosis in denervated laryngeal muscles, whereas others indicate resistance to atrophy. Spontaneous reinnervation has also been documented. The goal of this study was to clarify the effects of nerve injury and reinnervation on thyroarytenoid (TA) and posterior cricoarytenoid (PCA) muscles.


METHODS
Laboratory experiment.


METHODS
TA and PCA muscles of cats were harvested 5 to 6 months after transecting right or left recurrent laryngeal nerve (RLN). Images of muscle cross-sections were acquired and studied using an image analysis workstation. Cross-sectional areas as well as total cross-sectional area of randomly selected muscle fibers were recorded.


RESULTS
TA reinnervation was robust on both sides, but there was less reinnervation of the PCA muscle after left-sided RLN lesion than after right-sided injury.


CONCLUSIONS
Differences in reinnervation after RLN injury could contribute to the higher clinical incidence of left- vs. right-sided laryngeal paralysis.
Woodson
Gayle E
GE
Division of Otolaryngology, Southern Illinois University, School of Medicine, Springfield, Illinois 62794-9665, USA. gwoodson@siumed.edu
Hughes
Larry F
LF
Helfert
Robert
R
D000818:Animals; D002415:Cats; D003714:Denervation; D007821:Laryngeal Muscles / Q000473:pathology* / Q000503:physiopathology; D061226:Recurrent Laryngeal Nerve Injuries