Pulsed Radio Frequency Energy (PRFE) fields in the treatment of post-operative pain: a randomized, double-blind, sham-controlled pivotal study in the human bunion model

The post-bunionectomy pain model is a well-established post-operative analgesic pain model in the evaluation of analgesic pharmaceuticals. The assay sensitivity of the model makes this a generalizable model that is well suited for the evaluation of novel therapeutics. Over 50 pharmaceutical research protocols using this model have been submitted to FDA. The model has not, however, been applied previously to Medical Devices. We describe the first study of a medical device using the post-operative bunionectomy model and highlight the modifications to the traditional model that are necessary for device trials. Ours is a multi-center, randomized, double-blind, sham-controlled, prospective study of the efficacy of Pulsed Radio Frequency Energy (PRFE) in treatment of acute post-operative pain. PRFE is an adjunctive FDA-cleared biophysical modality that is thought to provide analgesia through incitement of the endogenous peripheral opioid pathway and reduction of post-operative inflammation. Treatment involves the local application of radio frequency electromagnetic fields to the surgical site in a non-contact, non-thermal fashion. Treatment is administered twice-daily by the patient at home through intact dressings. Side effects are rare and minor. In contrast to opioid therapy, there is no sedation or systemic side effects. In this trial, patients with moderate-severe post-operative pain are enrolled and self-report pain intensity every one-half to two hours over the 72-hour efficacy analysis period. The primary endpoint is the sum of time-weighted pain intensity differences (SPID) from the time of initiation of first postoperative treatment with the test device to 72 hours thereafter. Secondary outcome measures include total pain relief (TOTPAR), cumulative opioid consumption and time to first supplemental analgesic medication. Rescue analgesia with IV morphine and PO oxycodone are permitted, with data imputed to minimize confounding of the device effect by opioid consumption. The application of this widely accepted model to medical devices demonstrates its versatility.