Experimental study of the morphological and electromyographic characteristics of the most frequent iatrogenic lesions of the recurrent laryngeal nerves in thyroid surgery.
BACKGROUND
Iatrogenic lesions of the recurrent laryngeal nerves remain one of the most severe and frequent complications in thyroid surgery. According to Eisele (Laryngoscope 1996;106:443) their incidence varies between 1% and 12% depending on the size of surgery.


OBJECTIVE
The aim of the study was to examine experimentally the type of neural lesion and the efficiency of stimulation electromyography for immediate evaluation of the recurrent laryngeal nerve function in the most common surgical traumas.


METHODS
Ten clinically healthy and parasite-free male dogs of mixed breed weighing from 11 to 18 kg were used in the experiment. The injured laryngeal nerves of the experimental animals were examined histologically using Sudan III staining for myelin and Bilshovsky staining for neurofibrils. The intraoperative electromyography was performed with Neurostim 100.


RESULTS
The results show severe damage both of the myelin sheath and neurofibrils in most of the surgical traumas of the nerve fiber. The electromyography of the laryngeal musculature shows complete interruption of the conduction of the action potential in all types of experimental lesions.


CONCLUSIONS
EMG intraoperative monitoring of the laryngeal nerves appears the most effective measure to avoid the complication.
Dimov
Rosen S
RS
Department of Special Surgery, Third Surgical Clinic, Medical University--Plovdiv, Bulgaria.
Doikov
Ilian J
IJ
Zaprianov
Zaprian N
ZN
Stefanov
Chavdar S
CS
D000818:Animals; D004285:Dogs; D004576:Electromyography; D007049:Iatrogenic Disease / Q000517:prevention & control*; D007432:Intraoperative Period; D012009:Recurrent Laryngeal Nerve / Q000503:physiopathology; D061226:Recurrent Laryngeal Nerve Injuries; D013959:Thyroid Diseases / Q000601:surgery