Vibrating device eases pain during cutaneous cancer removal surgery
Applying a vibratory device while injecting a local anaesthetic reduces perceived pain in patients undergoing cutaneous cancer removal surgery, according to a recent study.
“The anticipation and fear of operative pain can result in significant psychological distress in many patients,” said researchers. “We hypothesized that vibration would reduce perceived pain at injection in both patients who catastrophized pain and patients who did not.”
Prior to anaesthetic injection, a vibratory anaesthetic device (VAD) was applied to 87 adults scheduled for surgical removal of cutaneous malignancies. A total of 101 discrete events (mean age, 66.0±11.3 years; 63.4 percent in males) were included in the analysis, 49 of which occurred with VAD switched on, while 52 happened with the device switched off. VAD was applied in the approximate location of the injection.
Twenty-six participants scored >4 in the anticipated Numeric Rating Scale (aNRS) and were identified as those who catastrophized pain. These patients scored significantly higher on the Numeric Rating Scale upon injection (iNRS) than their noncatastrophizing counterparts (2.27±0.66 vs 1.44±0.39; p=0.03). [JAMA Facial Plast Surg 2019;doi:10.1001/jamafacial.2019.0733]
VAD appeared to significantly reduce perceived pain. When switched on, the device elicited a 38.9-percent drop in mean iNRS score than when switched off (1.24±0.38 vs 2.04±0.54). This difference was deemed to be substantially clinically important.
VAD was more effective in those who did not catastrophize pain, such that the device produced a 79.4-percent greater decrease in iNRS when switched on vs off (1.02±0.40 vs 1.84±0.66). The difference was substantially clinically important.
In comparison, those who catastrophized pain experienced only a 25.5-percent drop in iNRS scores (1.91±0.99 vs 2.57±0.98), though still meeting the criteria for a minimally clinically important difference.
On the other hand, VAD bore no significant effect on overall aNRS scores, which were comparable between the on and off scenarios (2.67±0.64 vs 2.92±0.63). Subgroup analysis on those who did (5.75±0.86 vs 6.00±0.72) and did not (1.67±0.44 vs 1.79±0.41) catastrophize pain returned similar results.
“Our study recapitulates that vibration during local anaesthetic injection works in patients undergoing cutaneous cancer removal procedures,” regardless of pain catastrophizing, according to the researchers.
This was further confirmed in multivariate analysis, which showed that of all variables included in the model, only the active application of the VAD significantly affected iNRS scores (F, 2.741, p=0.03). Age, sex and aNRS scores, in contrast, were all unrelated to pain intensity during injection.
“Clinically, we will continue to use vibration on our patients; however, we recognize that those who catastrophize may require further intervention for pain relief in addition to vibration alone,” the researchers said, also noting that several methodological shortcomings warrant further inquiry into the subject.
“Investigations into how to accurately determine which patients will not respond to vibration would be helpful to pursue,” they added. “[F]uture studies should consider assessing the efficacy of other non-noxious tactile stimulation devices, sensations or techniques.”