Ice reduces needle-stick pain associated with a digital nerve block of the hallux

BackgroundDigital nerve blocks are widely used prior to minor surgery to the digits but the injections are associated with some degree of unwanted pain and anxiety. Methods to reduce the pain associated with injection, such as cryotherapy, are therefore worthwhile. However, cryotherapy (e.g. ice) applied prior to digital injections has received little scientific evaluation.ObjectiveThis study aimed to assess whether there was any change in pain associated with an injection into the hallux, if the site of injection was first refrigerated using ice.MethodTwenty participants each received two injections of lignocaine into the hallux (one each on the medial and lateral sides) as a standard digital nerve block. Prior to each injection, participants were randomized to receive either no-ice or a six-minute application of ice over the injection site. The primary outcomes were needle-stick pain and infiltration pain measured on a visual analogue pain scale.ResultsThe application of ice significantly reduced needle-stick pain, with the median scores for the no-ice and ice injections being 57 and 16 mm, respectively (P < 0.001). With respect to infiltration pain, however, there was no significant difference in the median scores (49 and 47 mm, respectively, P = 0.204). Nevertheless, 16 out of 20 participants preferred ice prior to the injection. Only four indicated no preference and none indicated a preference for no-ice.ConclusionIcing the digit prior to injection is an effective and inexpensive method to reduce the discomfort of a local anaesthetic injection.