The free neural grafting for recurrent nerve laceration Experimental study in rabbit.

AIM: The most dreaded complication of thyroidectomy is recurrent laryngeal nerve damage, which is most of the time hardly irreversible. In our experimental study we researched the use of free nerve grafts in the treatment of laryngeal nerve damage in rabbit. MATERIAL AND METHODS: There were three groups in our study. In the first group, the recurrent laryngeal nerve was severed and then a free nerve graft was interposed between the phrenic nerve and distal end of recurrent laryngeal nerve. In the second group, a defect in the continuity of the laryngeal nerve was created. The two ends of the nerve were joined together later by an interposed free nerve graft. In the third group, only a defect in the recurrent nerve was created without any attempt at uniting the ends together so that these latter subjects could be assigned as control group. In the evaluation process we performed laryngeal endoscopy, laryngeal EMG and histopathologic examination. RESULTS: On the 21. day of trial, in the first and second group vocal cord movements were detected on the laryngoscopy along with regeneration waves on EMG. In the third group there was no vocal cord movements on the side where a neural damage was created intentionally. On EMG there was degeneration waves as opposed to regeneration waves seen in the first and second groups. Histopathologic findings were similar. CONCLUSIONS: Recurrrent laryngeal nerve paralysis is an unwanted complication because it causes permenant sequela. Studies which intend to find a cure for this complication are increasing in number. We aim to find new approaches to cure patients suffering from this devastating complication as well. In our exprerimental study, vocal cord movements were reproduced without causing diaphragmatic paralysis. We believe the results of our study promise to relieve the suffering of patients. The results are encouraging. KEY WORDS: Muscle, Rat model, Reinnervation, Surgery.

Phrenic-recurrent nerve anastomosis in animal models with unilateral cutting of the recurrent nerve.

In our experimental study, the aim was to recover vocal cord physiology in cutting of recurrent laryngeal nerve, thus phrenic-recurrent nerve transposition was planned in rabbits. Experiments were performed on 10 experimental and 10 control rabbits. The right recurrent nerve was cut in the control group, while in the experiment group, the right recurrent nerve was cut. Then, a right phrenic-recurrent nerve end-to-end anastomosis was performed and the results were evaluated. After the 3rd postoperative week, videolaryngoscopy (VLS) and intramuscular electromyography (EMG) could not be evaluated in 1 rabbit from the experimental group which had died during anesthesia. In eight of the nine rabbits in the experiment which underwent VLS and EMG, activity was recorded in the right vocal cords. On light microscopic examination, atrophy was not detected in the vocal cord muscles of 9 rabbits among the 10 in the experiment group, while all rabbits in the control group and 1 rabbit in the experiment group were diagnosed with vocal cord atrophy. A success rate of approximately 90% was obtained based on the pathologic examination. We believe that the method can be used in patients without any contraindications, considering the complications of tracheostomy and the quality of life.