Therapeutic Effectiveness of Needle Injection Versus Needle-Free Jet Injector System for Botulinum Toxin Type A in Palmar Hyperhidrosis

Background: The most important problem with local injections of botulinum toxin type A (BTX-A) in palmar hyperhidrosis is pain during the injections. Objectives: We evaluated therapeutic effectiveness and pain of local injections of BTX-A using needle-free direct administration system. Methods: We performed BTX-A local injection therapy using a conventional injection needle in the left hand and a needle-free direct administration system in the right hand. Results: A reduction in the quantity of perspiration was observed 4 weeks after administration of both Needle and Needle-free BTX-A, and reduction was maintained throughout 28 weeks observation period. Both hyperhidrosis Disease Severity Scale scores and Dermatology Life Quality Index for hands treated with Needle BTX-A and hands treated with Needle-free BTX-A had decreased significantly by 4 weeks after treatment. Pain visual analog scale scores and the degree of pain were significantly lower in hands treated with Needle-free BTX-A than in hands treated with Needle BTX-A. Conclusions: When the trigger of the pressurized needle-free injector device is activated, the gas powered driving pressure propels BTX-A through an orifice (0.13 mm) about four times narrower than a 30 G needle at very high speed. As most pain occurs during the needle prick itself, the advantage of a small orifice coupled with high-speed penetration of BTX-A through the pressurized device results in reduced pain during administration. The needle-free direct administration system administers the injectate under the skin without a visible needle.