Repair of whole rabbit facial nerve defects using facial nerve allografts.
OBJECTIVE
To investigate the feasibility of repairing whole facial nerve defects with chemically extracted acellular whole facial allografts nerves and its effect on motor conductivity recovery.


METHODS
Whole nerve defects (branches and trunk) were made in 4 rabbit groups (n = 18), and the nerve defect was bridged using 1) acellular facial nerve allografts, 2) facial nerve isografts, 3) acellular peroneal nerve allografts, and 4) peroneal nerve isografts. Six months later, cell morphology, nerve microbeam distribution, angiogenesis, and collagen were observed in the distal and center of the grafts with special trichrome staining. The regenerated nerve fibers and Schwann cells in the anastomosis site were immunohistochemically stained. Nerve axon numbers and passing rates were analyzed with computer-captured images. The regenerated nerve ultrastructure was analyzed by transmission electron microscopy.


RESULTS
Regenerated nerve fibers and vessels were found in the grafts, with no differences between groups A and B. Groups C and D had poor nerve continuity with little vascular regeneration. The distal segments of nerve transplants in groups A and B showed strong positive neurofilament staining, higher than in groups C and D. In groups A and B, many long spindle-shaped Schwann cells proliferated longitudinally in the nerve transplant, but less in groups C and D. Myelinated nerve fibers were found in the distal facial nerve. There were no differences between groups A and B in fiber number and myelin sheath thickness, which were much lower than normal, whereas little myelin sheath regeneration was observed in groups C and D.


CONCLUSIONS
Chemically extracted acellular whole facial nerve allografts are feasible for repairing whole facial nerve defects.
Hu
Min
M
Department of Stomatology, Chinese PLA General Hospital, Beijing, People's Republic of China.
Zhang
Lihai
L
Niu
Yu
Y
Xiao
Hongxi
H
Tang
Peifu
P
Wang
Yan
Y
D000714:Anastomosis, Surgical; D000818:Animals; D001369:Axons / Q000502:physiology; D005154:Facial Nerve / Q000098:blood supply / Q000502:physiology / Q000637:transplantation* / Q000648:ultrastructure; D020220:Facial Nerve Injuries / Q000601:surgery*; D005240:Feasibility Studies; D005260:Female; D008297:Male; D018919:Neovascularization, Physiologic; D009413:Nerve Fibers, Myelinated / Q000502:physiology; D009416:Nerve Regeneration / Q000276:immunology; D016900:Neurofilament Proteins / Q000032:analysis; D010543:Peroneal Nerve / Q000637:transplantation; D011817:Rabbits; D009418:S100 Proteins / Q000032:analysis; D012583:Schwann Cells / Q000166:cytology; D020858:Tissue and Organ Harvesting / Q000379:methods
D016900:Neurofilament Proteins; D009418:S100 Proteins