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.