Pilot study on the effects of low intensity focused ultrasound in a swine model of neuropathic pain

OBJECTIVE The authors’ laboratory has previously demonstrated beneficial effects of noninvasive low intensity focused ultrasound (liFUS), targeted at the dorsal root ganglion (DRG), for reducing allodynia in rodent neuropathic pain models. However, rats DRG is 5 mm below skin when approached laterally, while humans typically 5–8 cm deep. Here, using a modified liFUS probe, authors feasibility external modulation antinociceptive responses swine. METHODS Two cohorts swine underwent common peroneal nerve injury (CPNI) to induce pain. In first cohort, pigs (14 kg) were iteratively tested determine treatment parameters. penetration L5 was verified by thermocouple monitor tissue temperature changes and measuring conduction velocity (NCV) corresponding (CPN). Pain behaviors monitored before after treatment. evaluated damage postmortem. Based on data from algorithm developed, parameter predictions verified, significantly second cohort larger (20 kg). RESULTS performed dose-response curve analysis 14-kg CPNI Specifically, confirming that probe could reach ex vivo experiments, mean ± SEM depth 3.79 0.09 this initial cohort. parameters determined then extrapolated animals kg), verified. Tissue elevations site did not exceed 2°C, expected increases CPN NCV observed. eliminated guarding all duration follow-up (up 1 month) improved days postprocedure. No evidence histological seen Fluoro-Jade H&E staining. CONCLUSIONS results demonstrate 5-cm can be reached with alters behavior large-animal model