Cutaneous anaesthesia of the lower leg can improve sensibility in the diabetic foot. A double-blind, randomized clinical trial.
OBJECTIVE
Impaired sensory function in the sole of the foot in diabetic patients is a substantial problem caused by unknown mechanisms. Hand or foot sensibility can be improved by cutaneous anaesthesia of the forearm or lower leg, respectively, in healthy subjects. Hypothetically, cutaneous anaesthesia induces a silent area in the primary somatosensory cortex, allowing adjacent cortical areas to expand; thus, resulting in enhanced sensory processing. Our aim was to improve sensory function in the foot in Type 1 and Type 2 diabetic patients by application of an anaesthetic cream to the lower leg.


METHODS
In a double-blind study, 37 patients with Type 1 or Type 2 diabetes were randomly assigned to cutaneous application of either an anaesthetic cream (EMLA) or a placebo cream to the skin of the lower leg for 1.5 h. Sensibility at five points of the sole of the foot was assessed before and after 1.5 and 24 h. Vibrotactile sense was also assessed. Primary outcome was change of touch threshold at the first metatarsal head from pretreatment to 1.5 h assessment.


RESULTS
Anaesthetic cream on the lower leg resulted in a significant improvement of touch threshold at the first metatarsal head after 1.5 and 24 h. In addition, improvement of touch thresholds was also observed at the other four assessment sites, together with a decreased vibration threshold at 125 Hz.


CONCLUSIONS
The findings of improved touch thresholds open up new possibilities in treatment of sensibility disturbances in the diabetic foot, using a simple and non-invasive method.
Lundborg
G N
GN
Department of Hand Surgery Malmö-Lund, Skåne University Hospital, Malmö, Sweden.
Björkman
A C G
AC
Rosén
B N
BN
Nilsson
J-A
JA
Dahlin
L B
LB
D000368:Aged; D000779:Anesthetics, Local / Q000627:therapeutic use*; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D017719:Diabetic Foot / Q000188:drug therapy* / Q000503:physiopathology; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000188:drug therapy* / Q000503:physiopathology; D012684:Sensory Thresholds / Q000187:drug effects*; D013548:Sweden; D016896:Treatment Outcome
D000779:Anesthetics, Local