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Digital Nerve Block: One Injection Is as Good as Two
Preliminary data support use of a single-injection method for fingertip injuries and infections.

The traditional method of digital nerve block involves two subcutaneous injections with the dorsal approach to block the four digital nerves at the base of the finger. An alternative approach involves a single subcutaneous injection of 2 to 3 mL of local anesthetic on the palmar surface at the base of the digit just distal to the proximal skin crease, followed by massage of the anesthetic into the area. Researchers conducted a multicenter, randomized controlled trial to compare these two methods in 76 patients older than 16 years who presented to three emergency departments in the U.K. with fingertip injuries or infections that required local anesthesia.

The proportion of patients who were adequately anesthetized did not differ significantly between the one-injection and two-injection groups at 5 minutes (76% and 65%) or at 10 minutes (89% and 82%). Clinician satisfaction scores were significantly higher for the one-injection technique (mean, 8.1 vs. 6.8 on a 10-point scale).

Comment: The authors could not recruit the intended 500 patients to adequately power the study, in part because many clinicians preferred the subcutaneous method and adopted it as their normal practice. This simple single-injection approach works beautifully to anesthetize the distal finger; however, because this method does not block the dorsal branches of the digital nerve, it might be less effective for injuries proximal to the distal-interphalangeal joint.

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Diane M. Birnbaumer, MD, FACEP
Published in Journal Watch Emergency Medicine August 13, 2010

Citation(s): Cannon B et al. Digital anaesthesia: One injection or two? Emerg Med J 2010 Jul; 27:533.