LIDOCAINE VIA IONTOPHORESIS IN LACERATION REPAIR - A PRELIMINARY SAFETY STUDY

Ionotophoresis is a painless technique for topical anesthesia that use s an electric field to drive charged ions across an epithelial surface . The safety of this technique for laceration repair has never been de monstrated. The purpose of this study was to investigate the effect of iontophoretic fields on rapidly proliferating cells involved in lacer ation wound healing. The study was a prospective single-blinded animal study using a guinea pig model. Twelve guinea pigs each received four induced, uncontaminated lacerations. Each guinea pig was randomly ass igned to 1 of 3 groups (4 guinea pigs in each group). One group receiv ed lidocaine via iontophoresis, one group received injected lidocaine, and one group received half iontophoresis and half injected lidocaine . After anesthetic treatment, wounds were then repaired in a standard fashion. The wounds were examined grossly on a daily basis and on day 10 the incised skin containing the laceration was examined by a pathol ogist blinded to the treatment group. A total of 48 wounds were assess ed for wound healing, 24 of which received lidocaine via ionotophoresi s and 24 lidocaine via injection. The power of the study to determine a 40% difference between the two groups was 0.8. There was significant ly more granuloma and granulation tissue formation in the iontophoresi s group than in the injected lidocaine control group (P = .0004, Fishe r's exact test). There were no statistically significant differences i n degree of inflammation between the two groups (lidocaine via injecti on v lidocaine via iontophoresis) measured by amount of dermal fibrosi s (P = .14, Fisher's exact test), giant cell formation (P = .21, Fishe r's exact test), and presence of acute and/or chronic inflammation (P = .17, Wilcoxon's rank sum test). Wound healing proceeded normally wit h 100% in both groups having normal scar formation and healing at day 10. In conclusion, iontophoresis appears to be a safe method of anesth esia delivery in this guinea pig model with lacerations. Increased gra nuloma and granulation tissue formation may indicate an enhancement of wound healing via iontophoresis.