Comparative analysis of stimulated sciatic nerve regeneration by ultrasound and therapeutic low-level laser therapy

Background:    Peripheral nerves are common targets of traumatic injuries, which cause reduction in or loss of feeling and motor activity in innervated regions. Many studies have employed low-level laser therapy and therapeutic ultrasound for functional improvement in injured peripheral nerves. Our objective was to determine the effects of laser therapy and ultrasound on peripheral nerve (sciatic) regeneration following injury.
    Material/Methods:    Forty Wistar rats weighing 250 g were divided into Group 1 (laser irradiation, n=20) and Group 2 (therapeutic ultrasound, n=20), each subdivided into 4 subgroups (n=5). Group 1 was subdivided into groups receiving irradiation at 4 J/cm2, 10 J/cm2, and 20 J/cm2, and a control subgroup. Group 2 was subdivided into groups receiving ultrasound at 0.8 W/cm2, 1.5 W/cm2, and 2 W/cm2, and a control subgroup. Sciatic nerve injury was surgically induced in the posterior region of the greater trochanter of the hind leg and crushing with a hemostat for 10 s. Recovery analysis was performed using the sciatic functional index (SFI).
    Results:    SFI analysis: control ultrasound group, –76.16 to –50.52; 0.8 W/cm2 group, –61.37 to –65.61; 1.5 W/cm2 group, –76.81 to –58.92; 2 W/cm2 group, –83.51 to –61.60; laser control group –88.72 to –30.32 (difference: –58.40); 4 J/cm2 group, –74.26 to –19.91; 10 J/cm2 group, –83.45 to –33.54; and 20 J/cm2 group, –97.02 to –29.84. There were no significant inter-group differences.
    Conclusions:    Laser irradiation promoted more rapid regeneration and recovery than did therapeutic ultrasound.

Keywords: low-level laser therapy, therapeutic ultrasound, Nerve Regeneration