Effects of laser therapy in peripheral nerve regeneration

OBJECTIVE The influence of dose of low power lasertherapy (AsGaAl, 830 nm) on the regeneration of the fibular nerve of rats after a crush injury was evaluated by means of the functional gait analysis and histomorphometric parameters. METHODS Controlled crush injury of the right common fibular nerve, immediately followed by increasing doses (G1: no irradiation; G2: simulated; G3: 5 J/cm(2); G4: 10 J/cm(2); G5: 20 J/cm(2)) laser irradiation directly on the lesion site for 21 consecutive days. Functional gait analysis was carried out at weekly intervals by measuring the peroneal/fibular functional index (PFI). The animals were killed on the 21(st) postoperative day for removal of the fibular nerve, which was prepared for the histomorphometric analysis. RESULTS The PFI progressively increased during the observation period in all groups, without significant differences between them (p>0.05). The transverse nerve area was significantly wider in group 2 than in groups 3 and 4, while fiber density was significantly greater in group 4 than in all remaining groups. CONCLUSION The low power AsGaAl laser irradiation did not accelerate nerve recovery with any of the doses used. Level of Evidence I, Therapeutic Studies Investigating the Results of Treatment.