Background:
In this experimental protocol, we evaluated the immediate and delayed repair
of the buccal branch of the facial nerve (BBFN) with heterologous fibrin
biopolymer (HFB) as a coaptation medium and the use of photobiomodulation
(PBM), performing functional and histomorphometric analysis of the BBFN and
perioral muscles.
Methods:
Twenty-eight rats were divided into eight groups using the BBFN bilaterally
(the left nerve was used for PBM), namely: G1 - control group, right BBFN
(without injury); G2 - control group, left BBFN (without injury + PBM); G3 -
Denervated right BBFN (neurotmesis); G4 - Denervated left BBFN (neurotmesis
+ PBM); G5 - Immediate repair of right BBFN (neurotmesis + HFB); G6 -
Immediate repair of left BBFN (neurotmesis + HFB + PBM); G7 - Delayed repair
of right BBFN (neurotmesis + HFB); G8 - Delayed repair of left BBFN
(neurotmesis + HFB + PBM). Delayed repair occurred after two weeks of
denervation. All animals were sacrificed after six weeks postoperatively.
Results:
In the parameters of the BBFN, we observed inferior results in the groups
with delayed repair, in relation to the groups with immediate repair, with a
significant difference (
p
< 0.05) in the diameter of the
nerve fiber, the axon, and the thickness of the myelin sheath of the group
with immediate repair with PBM compared to the other experimental groups. In
measuring the muscle fiber area, groups G7 (826.4 ± 69.90) and G8 (836.7 ±
96.44) were similar to G5 (882.8 ± 70.51). In the functional analysis, the
G7 (4.10 ± 0.07) and G8 (4.12 ± 0.08) groups presented normal parameters.
Conclusion:
We demonstrated that delayed repair of BBFN is possible with HFB, but with
worse results compared to immediate repair, and that PBM has a positive
influence on nerve regeneration results in immediate repair.