Application of a three-microneedle device for the delivery of local anesthetics

PURPOSE We investigated the effectiveness of a newly developed device for the delivery of local anesthetics in the treatment of axillary osmidrosis and hyperhidrosis. We developed a device with three fine, stainless steel needles fabricated with a bevel angle facing outside ("three-microneedle device" [TMD]) to release a drug broadly and homogeneously into tissue in the horizontal plane. Use of this device could reduce the risk of complications when transcutaneous injections are undertaken. PATIENTS AND METHODS Sixteen Japanese patients were enrolled. The mean volume of lidocaine hydrochloride per unit area needed to elicit anesthesia when using a TMD was compared with that the volume required when using a conventional 27-gauge needle. The visual analog scale (VAS) score of needlestick pain and injection-associated pain was also compared. RESULTS The mean volume of lidocaine hydrochloride per unit area to elicit anesthesia using the TMD was significantly lower than that the volume required when using the conventional 27-gauge needle. The VAS score of needlestick pain for the TMD was significantly lower than that the VAS score for the 27-gauge needle. CONCLUSION These data suggest that the TMD could be useful for the delivery of local anesthetics in terms of clinical efficacy and avoidance of adverse effects.