Protective glottic closure: biomechanical effects of selective laryngeal denervation.
Glottic closure constitutes the primary mechanism for prevention of intradeglutitive and postdeglutitive aspiration. Laryngeal paralysis therefore exerts a considerable impact on deglutition, yet little is understood regarding the biomechanical effects of selective denervation on the laryngeal protective function. We measured the glottic closing force (GCF) in each of 6 male, 40-kg Yorkshire pigs 1) after selective unilateral superior laryngeal nerve (SLN) section; 2) after selective unilateral recurrent laryngeal nerve (RLN) section; and/or 3) after combined SLN-RLN section as both right and left SLNs were simultaneously stimulated to evoke the glottic closure response. Stimulation was provided through an oscilloscope with bipolar platinum-iridium electrodes, and the GCF was measured with a pressure transducer positioned between the vocal cords. Six repetitive measures of GCF were obtained before nerve section, and 6 after nerve section, in each subject. Unilateral SLN section reduced the GCF to 54.14% of control, RLN section reduced the GCF to 23.39% of control, and combined SLN-RLN section reduced the GCF to 22.67% of control. These findings underscore the profound differential effects exerted by isolated lesions on the glottic closure function.
Sasaki
Clarence T
CT
Section of Otolaryngology, Dept of Surgery, Yale School of Medicine, 333 Cedar St, PO Box 208041, New Haven, CT 06520-8041, USA.
Hundal
Jagdeep S
JS
Kim
Young-Ho
YH
D000818:Animals; D001696:Biomechanical Phenomena; D003714:Denervation; D004558:Electric Stimulation; D004576:Electromyography; D005931:Glottis / Q000294:innervation* / Q000503:physiopathology*; D007821:Laryngeal Muscles / Q000294:innervation / Q000502:physiology; D007823:Laryngeal Nerves / Q000502:physiology*; D008297:Male; D011015:Pneumonia, Aspiration / Q000503:physiopathology / Q000517:prevention & control; D012018:Reflex / Q000502:physiology; D012684:Sensory Thresholds / Q000502:physiology; D013552:Swine; D014159:Transducers; D014826:Vocal Cord Paralysis / Q000503:physiopathology