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Pain Research and Treatment
Volume 2011, Article ID 362396, 6 pages
Clinical Study

Pain and Efficacy Rating of a Microprocessor-Controlled Metered Injection System for Local Anaesthesia in Minor Hand Surgery

1The Hand and Upper Limb Centre, St. Joseph's Health Centre, The University of Western Ontario, London, ON, Canada N6A 4L6
2Division of Plastic Surgery, University of Western Ontario, London, Ontario, Canada N6A 4L6
3Division of Orthopedic Surgery, University of Western Ontario, London, ON, Canada N6A 4L6
4Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada N6A 5C1
5Department of Medical Biophysics, University of Western Ontario, London, ON, Canada N6A 5C1

Received 23 October 2010; Accepted 21 March 2011

Academic Editor: Michael G. Irwin

Copyright © 2011 André S. Nimigan and Bing Siang Gan. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Purpose. Little attention has been given to syringe design and local anaesthetic administration methods. A microprocessor-controlled anaesthetic delivery device has become available that may minimize discomfort during injection. The purpose of this study was to document the pain experience associated with the use of this system and to compare it with use of a conventional syringe. Methods. A prospective, randomized clinical trial was designed. 40 patients undergoing carpal tunnel release were block randomized according to sex into a two groups: a traditional syringe group and a microprocessor-controlled device group. The primary outcome measure was surgical pain and local anaesthetic administration pain. Secondary outcomes included volume of anaesthetic used and injection time. Results. Analysis showed that equivalent anaesthesia was achieved in the microprocessor-controlled group despite using a significantly lower volume of local anaesthetic ( ). This same group, however, has significantly longer injection times ( ). Pain during the injection process or during surgery was not different between the two groups. Conclusions. This RCT comparing traditional and microprocessor controlled methods of administering local anaesthetic showed similar levels of discomfort in both groups. While the microprocessor-controlled group used less volume, the total time for the administration was significantly greater.