New Study Finds Vibration Testing More Reliable than Monofilament over Plantar Calluses
Wynands et al’s recently published “Does plantar skin abrasion affect cutaneous mechanosensation?” brings into focus the importance of plantar callus debridement. This study measured skin thickness, hardness, monofilament threshold and vibration perception threshold (VPT) in healthy participants over plantar calluses before and after “abrasion” (debridement). The intervention group was compared to a matched control group without callus debridement. Findings included significantly reduced skin thickness and hardness as to be expected after callus debridement. Interestingly, VPTs at 30Hz and 200Hz were not significantly affected by debridement. Monofilament thresholds however were significantly improved after the intervention. This finding led the authors to conclude:
“Since VPTs are not affected by skin properties, they are likely to be the best choice to analyze sensory deterioration in diabetic feet, where skin property changes could skew data of devices like monofilaments.”
This recommendation aligns with American Diabetes Association Guidelines for using vibration(large-fiber function) and pinprick/temperature (small-fiber function) testing along with the 10g monofilament when testing for loss of protective sensation (LOPS) in patients with diabetes. Another conclusion drawn from this study is that callus debridement improves light touch perception in healthy study participants. Future studies might evaluate this intervention in patients with varying degrees of diabetic peripheral neuropathy (DPN). Perhaps in addition to reducing pressures on the skin, debridement also will be found to improve skin sensitivity in this at risk group.