Video endoscopy has a widespread use in respiratory problems of the upper airways. Several flexible or rigid scopes are at our disposal to perform gastroscopy, sinuscopy, oroscopy, cystoscopy and many more. We do offer dynamic endoscopy as well.
Functional electrical stimulation of the left recurrent laryngeal nerve with an implanted vagal nerve electrical stimulation device in a normal horse.,
K. Vanschandevijl 1, H. Nollet1, K. Vonck2, P.Boon2, R. Raedt2, Van Roost2, A. Martens1, , P. Deprez1 1 Faculty of Veterinary Medicine, Ghent University, Belgium, 2 Faculty of Medicine, Ghent University Hospital, Belgium
Electrical stimulation of the left recurrent laryngeal nerve (RLN) could offer a potential approach to restore left arythenoid abduction in left laryngeal hemiplegia. The purpose of this investigation was to assess the feasibility of implantation of a stimulating electrode attached to the left recurrent laryngeal nerve and determine stimulation parameters in order to achieve abduction of the left arytenoid cartilage in a horse with normal arythenoïd function. One normal horse underwent implantation of a Cyberonics vagal nerve stimulation electrode (3.00 mm, model 302) winded around the left RLN and connected to a pulse generator (Cyberonics, model 102) which allows stimulation parameters to be adjusted by a telemetric wand. Intraoperative stimulation and evaluation of arythenoid abduction using a laryngoscope demonstrated abduction of the left laryngeal arythenoid. Postoperative stimulation was performed on the non-sedated horse and stimulus response characteristics were obtained by measuring stimulated arythenoid displacement endoscopically. Stimulus intensities ranging from 0.25 – 1 mA and stimulus frequencies ranging from 1 – 30 Hz were well tolerated by the horse. Video images were digitized and analyzed using Image J and Virtual Dub to measure the change in position of the arythenoid cartilage at rest and during stimulation. Abduction was noted with stimulation frequencies ranging from 2 – 30 Hz and stimulation intensity of 1 mA (pulse width 250 µsec during 30 sec) but a continuous abduction was obtained with stimulation frequencies of 25-30 Hz and intensity of 1 mA (250 µsec pulse width during 30 sec) (figure). These data support the feasibility of implantation of a commercially available stimulation device that allows functional electrical stimulation of the left RLN and could assist in restoring arythenoid abduction in horses with recurrent laryngeal neuropathy.
Endoscopic images of the larynx A left arythenoid before stimulation B abduction of the left arythenoid with stimulation at 25 Hz, 1 mA, 250 µsec, 30 sec