Selective laryngeal abductor reinnervation in cats using a phrenic nerve transfer and ORG 2766
H. F. Mahieu, J. T. van Lith-Bijl, C. Groenhout, J. A. Tonnaer and P. de Wilde
Department of Otolaryngology-Head and Neck Surgery, Free University Hospital, Amsterdam, The Netherlands.
Reinnervation of the recurrent laryngeal nerve following nerve injury often
leads to laryngeal synkinesis. Selective reinnervation of adductor and
abductor muscles might be able to avoid synkinesis. This study presents the
results of selective abductor reinnervation in cats, using a phrenic nerve
transfer to the recurrent laryngeal nerve and directing all reinnervating
axons toward the abductor muscle. Simultaneously, a blind,
placebo-controlled, pilot study was performed to evaluate the capacity of
ORG 2766, administered subcutaneously (25 micrograms/kg per 48 hours), to
facilitate reinnervation by stimulation of axon sprouting. Reinnervation
surgery was performed in 10 cats. Postoperative evaluation included
videolaryngoscopy, electromyography, histological examination, and
quantification of reinnervating axons. Nine cats could be evaluated, of
which eight demonstrated electromyographic and laryngoscopic activity as
soon as 6 weeks following surgery. The one cat showing no abduction was
found to have an inadequate nerve anastomosis and was marked as a surgical
failure. After 10 weeks, near-normal or more than normal abduction was seen
in the eight cats, and histological proof of reinnervation was obtained in
seven of them; one cat could not be evaluated histologically owing to
unsuccessful fixation. Although no conclusive evidence was obtained
concerning the effect of ORG 2766, the tendencies found warrant further
experiments with this compound on laryngeal reinnervation.
