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Effect of magnitude and direction of force on laryngeal abduction: Implications for the nerve‐muscle pedicle graft technique
Author(s) -
CRAMP P.,
DERKSEN F. J.,
STICK J. A.,
FEIJTERRUPP H.,
ELVIN N. G.,
HAUPTMAN J.,
ROBINSON N. E.
Publication year - 2009
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.2746/042516409x388208
Subject(s) - anatomy , cadaver , medicine
Summary Reasons for performing study : The nerve‐muscle pedicle graft technique is a treatment for recurrent laryngeal neuropathy (RLN), but the optimal placement of the pedicles within the cricoarytenoideus dorsalis (CAD) muscle is unknown. Hypothesis : The magnitude and direction of force placed on the muscular process of the left arytenoid cartilage affects the magnitude of laryngeal abduction. Methods : Five larynges were harvested from cadavers. Using increments of 0.98 N, a dead‐weight force generator applied a force of 0–14.7 N for 1 min each to the left muscular process at 0, 10, 20, 30, 40, 50, 60 and 70° angles. The rima glottis was photographed digitally 1 min after each force had been applied. Distances between biomarkers (Lines 1–4) and right to left angle quotient (RLQ) were used to assess the degree of left arytenoid abduction. Results : Increasing force from 0–14.7 N progressively and significantly increased the length of all lines and RLQ, indicating abduction. Furthermore, there was a significant interaction between force and angles. Applying forces of 7.84 N or greater (Lines 2–4 and RLQ) or 11.76 N or greater (Line 1) at angles 0, 10, 20 and 30° resulted in significantly greater abduction than applying the same forces at 40, 50, 60 and 70°. Angles of 0–30° correspond with the direction of pull exerted by the lateral compartment of the CAD muscle. Conclusion : In RLN, nerve‐muscle pedicle grafts should be placed preferentially in the lateral rather than in the medial compartment of the CAD muscle. Potential relevance : The information presented can be used to assist surgeons in the planning and application of the nerve‐muscle pedicle graft procedure.