The effects of ultrasonic energy on peripheral nerves: Implications for ultrasound-assisted liposuction

The integration of ultrasound-assisted liposuction with traditional suction -assisted lipoplasty has extended the role of liposuction in body contourin g. Although there are ample data regarding the effects of ultrasound on per ipheral nerves from studies with the Cavitron ultrasound surgical aspirator , there is little information concerning the effects of modern ultrasound b ody contouring equipment on neural tissue. This study was designed to evaluate the functional and histologic effects o f ultrasound energy on rat peripheral nerves (sciatic nerves) using a commo nly-used ultrasound-assisted liposuction generator. After the application o f ultrasound to exposed rat sciatic nerves, operative mag nification was us ed to assess any visible injury. The sciatic function index was serially me asured to quantify immediate and long-term functional effects on the nerves . Our results showed immediate visible injury using low amplitude settings (level 6), but no functional evidence of injury until much higher settings were used (level 9). All animals in the groups with initial functional impa irment had returned to normal or near-normal function at completion of the study (51 days). Histologic examination revealed no evidence of damage in t he low amplitude groups. Histologic analysis of the high amplitude groups d isplayed diffuse infiltration of the nerve, with foamy histiocytes and an i ncreased number of mast cells, consistent with remote neural injury followe d by myelin breakdown and repair.