Hyaluronidase to Reduce Pain from Local Anaesthetic Infiltration for Carpal Tunnel Decompression.

Abstract Aims: The aim of this prospective cohort study is to investigate the effect of hyaluronidase on pain experienced during local anaesthetic infiltration for carpal tunnel decompression. Methods: Two cohorts of twenty consecutive patients each underwent carpal tunnel release by a single surgeon over a five-month period. The first twenty patients received a local anaesthetic solution of lignocaine and adrenaline whilst the second group received a mixture of lignocaine, adrenaline and hyaluronidase (Hyalase®). All consecutive patients booked for simple open carpal tunnel decompression under local anaesthesia were included. Patients with other compressive neuropathies, generalised neuropathies or other concomitant hand pathologies were excluded from the study. The primary outcome measurement was pain experienced during local anaesthetic infiltration. Patients were asked to indicate the level of pain felt using a visual analogue scale (VAS) between 0 (no pain) to 10 (maximum pain they can imagine). Secondary outcome measures were operating time, measured as tourniquet time and early complication rates. Results: Patients administered local anaesthesia with hyaluronidase experienced significantly less pain on infiltration of the proximal palm (p < 0.05) and distal palm (p < 0.05) compared to those that did not receive hyaluronidase. Infiltration of the palm was the most painful part of the procedure for both groups. There was no statistically significant difference in pain reported on initial needle insertion (p = 0.95) or on infiltration of the distal forearm (p = 0.10). No patients in either group required additional local anaesthetic. The mean tourniquet time for the group receiving local anaesthesia without hyaluronidase was 3.79 minutes (range 3 to 5 minutes, SD 0.71) versus to 3.65 minutes (range 3 to 5 minutes, SD 0.67) for the hyaluronidase group. There was therefore no significant difference in operating time between the two cohorts (p = 0.53). No early complications were observed in either groups. Conclusion: This study finds that hyaluronidase is effective at reducing pain during local anaesthetic infiltration for carpal tunnel release. We therefore recommend its routine use.