Paralyzed masseter muscle reinnervation by facial nerve implantation or anastomosis: a comparative study in rabbits.
OBJECTIVE
To investigate the changes in the physiological and structural properties of the masseter muscle after reinnervation through different reinnervation methods.


METHODS
Twenty-four adult rabbits were randomly divided into groups A and B (n=12) after the establishment of masseter muscle paralysis, followed by facial nerve anastomosis with the masseteric nerves in group A and facial nerve implantation into the masseter muscle in group B. At 1, 3 and 6 months after the operation, gross observation and wet weight measurement of the muscles were conducted along with myoelectric activity and enzyme- histochemical analyses and ultrastructural observation as well.


RESULTS
The reinnervation of the masseter muscle by both facial nerve anastomosis and implantation was confirmed and the muscles recovered their motion of contraction activity. Changes took place in the histochemical types of the muscle fibers, which tended to assume the properties typical of facial muscles. Three months after the operation, the muscle fiber conduction velocity recovery after the reinnervation by the two methods was significantly different (P<0.01), but not so till 6 months postoperatively (P>0.05).


CONCLUSIONS
This two methods are both effective in the reinnervation of the muscles, but in one-stage operation, intramuscular nerve implantation is relatively less complicated in operation and causes less damage while producing similar effects to that by nerve anastomosis.
Ji
Hang
H
Department of Plastic Surgery, Nanfang Hospital, First Military Medical University, Guangzhou 510515, China. jihang2001@hotmail.com
Hu
Zhi-qi
ZQ
D000714:Anastomosis, Surgical; D000818:Animals; D004195:Disease Models, Animal; D005154:Facial Nerve / Q000601:surgery*; D005158:Facial Paralysis / Q000601:surgery*; D005260:Female; D008297:Male; D008406:Masseter Muscle / Q000294:innervation* / Q000601:surgery; D016067:Nerve Transfer; D011817:Rabbits