REV I EW Open Access Tourniquet-induced nerve compression injuries are caused by high pressure levels and gradients – a review of the evidence to guide safe surgical, pre-hospital and blood flow restriction usage Bassam A. Masri 1 , Andrew Eisen 2 , Clive P. Duncan 1 and James A. McEwen 1,3* Abstract Tourniquets in orthopaedic surgery safely provide blood free surgical fields, but their use is not without risk. Tourniquets can result in temporary or permanent injury to underlying nerves, muscles, blood vessels and soft tissues. Advances in safety, accuracy and reliability of surgical tourniquet systems have reduced nerve-related injuries by reducing pressure levels and pressure gradients, but that may have resulted in reduced awareness of potential injury mechanisms. Short-term use of pre-hospital tourniquets is effective in preventing life-threatening blood loss, but a better understanding of the differences between tourniquets designed for pre-hospital vs surgical use will provide a framework around which to develop guidelines for admitting to hospital individuals with pre- applied tourniquets. Recent evidence supports the application of tourniquets for blood flow restriction (BFR) therapy to reduce muscular atrophy, increase muscle strength, and stimulate bone growth. BFR therapy when appropriately prescribed can augment a surgeon ’ s treatment plan, improving patient outcomes and reducing recovery time. Key risks, hazards, and mechanisms of injury for surgical, BFR therapy, and pre-hospital tourniquet use are identified, and a description is given of how advances in personalized tourniquet systems have reduced tourniquet-related injuries in these broader settings, increasing patient safety and how these advances are improving treatment outcomes. Keywords: Tourniquet, Pressure, Nerve, Compression, Injuries, Safety, Personalization Background Tourniquets have been used for centuries to occlude arter- ial flow distal to the device to control extremity bleeding and provide a clearer surgical field. Generations of tourni- quet technology have evolved over time, from simple cloth bands tied tightly around limbs, to mechanical screw tour- niquets, to elastic, non-pneumatic Esmarch tourniquets, and most recently to the current generation of micropro- cessor controlled pneumatic tourniquets first conceived and developed by McEwen in 1981 [1 – 3]. Reports of limb paralysis, serious nerve damage, and a range of other injur- ies were common with early generations of tourniquets [2, 4]. However, progressions in recent generations of pneu- matic tourniquet technology, highlighted by advances in personalized tourniquets, have substantially reduced the frequency and severity of such injuries [5]. An exception to © The Author(s). 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data. * Correspondence:
[email protected] 1 Department of Orthopaedics, Faculty of Medicine, University of British Columbia, 207-1099 West 8th Avenue, Vancouver, BC V6H 1C3, Canada 3 Department of Electrical and Computer Engineering, University of British Columbia, Vancouver, Canada Full list of author information is available at the end of the article BMC Biomedical Engineering Masri et al. BMC Biomedical Engineering (2020) 2:7 https://doi.org/10.1186/s42490-020-00041-5 FEBRUARY 2021 | The Surgical Technologist | 67