Use of an external vibratory device as a pain management adjunct for injections to the foot and ankle

Abstract

Objectives: Pain modulation through the combined effect of vibratory stimulation of Aβ mechanoreceptors and cold thermal stimuli has been demonstrated to reduce the pain associated with injections and IV cannulation. Although past reports have focused on its use on the upper extremity, there are no current studies to evaluate the efficacy of these combined modalities for lower extremity injections. The authors propose the combined use of vibratory stimulation with cold thermal stimulation will yield lower reported pain values associated with injection compared to cold thermal stimulation alone. Methods: In this multicenter, randomized, prospective clinical trial, 108 patients necessitated a lower extremity injection for the treatment of their presenting condition and was randomized into a treatment (vibration and cold spray) or control (cold spray only) groups. The primary outcome was pain, subjectively measured on a 10-point numerical pain rating scale (NPRS) by the patient. Pain was also ranked by an observing physician via the Wong-Baker Pain Faces Ranking Scale (WBPFRS). Results: Forty treatment subjects and 68 control subjects were included in this study. Pain scores were significantly lower in the treatment group receiving the vibratory device and the cold spray compared to the cold spray alone (NPRS mean values: Treatment: 3.39, Control: 4.46; p=0.022. WBPFRS mean values: Treatment: 2.29, Control: 4.05; p=0.030). Discussion: Utilizing a combination of cold spray with vibratory stimulation produced a statistically significant decrease in pain associated with lower extremity injections. Due to the relatively small size of our study, further investigation is needed to assess effect on specific injection site.