Review Biomechanics of thoracolumbar burst fractures: Methods of induction and treatments Shayan Fakurnejad a , Justin K. Scheer a , Avinash G. Patwardhan b,c , Robert M. Havey b,c , Leonard I. Voronov b,c , Zachary A. Smith a,⇑ a Department of Neurological Surgery, Northwestern University, Feinberg School of Medicine, 676 N. St. Clair Street, Suite 2210, Chicago, IL 60611, USA b Department of Orthopaedic Surgery, Loyola University, Stritch School of Medicine, Maywood, IL, USA c Musculoskeletal Biomechanics Laboratory, Rehabilitation Research and Development Center, Edward Hines Jr. VA Hospital, Hines, IL, USA article info Article history: Received 23 April 2014 Accepted 4 May 2014 Available online xxxx Keywords: Biomechanics Burst fracture Spine Thoracolumbar abstract Much controversy exists regarding the mechanism of burst fracture (BF) induction and the proper tech- niques to treat such fractures. As such, there is a great need for validated preclinical models in which to study these injuries. In this study, an electronic search of the PubMed database (MEDLINE) was per- formed and the results were filtered to obtain only studies with a biomechanical focus. Forty five biome- chanical studies were obtained, from which four distinct methods of injury induction were identified. Twenty one (46.7%) involved clinically relevant techniques for treating BF, involving anterior, posterior, circumferential, or a combination of approaches. Fifteen (71.4%) of the treatment studies used unstable spine specimens that do not fit the classical characteristics of BF. Given the consistent use of BF models that do not adhere to classical definitions, the clinical value of ex vivo induction is uncertain. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction Spinal burst fractures (BF) have been defined as a specific type of compression fracture involving the anterior and middle verte- bral columns [1] that may result in a retropulsion of posterior ver- tebral body fragments into the spinal canal [2]. About 90% of all fractures of the spine occur in the thoracolumbar region, and about 15% of these injuries are classified as BF, making these the most prevalent unstable fracture of the thoracolumbar spine [1–3]. This is likely a result of the biomechanical properties of the thoracolum- bar junction as a mechanical transition zone, from the relatively immobile kyphotic thoracic region to the mobile lordotic lumbar region [4]. However, while BF are common, much controversy exists regarding how the fractures occur and how to properly treat such fractures. Patients can be treated either operatively, often involving a combination of spinal fixation and fusion using various constructs with grafts, rods, screws, plates, and cages [5–10], or nonoperatively, often with a combination of casts, braces, recumb- ence, and/or analgesics [5,7,8,11–13]. The decision to treat opera- tively or nonoperatively is a topic of debate, especially in neurologically intact BF patients, who make up approximately half of all presenting patients [1]. Numerous studies have been performed examining the effectiveness of operative versus nonop- erative methods of treatment, and to our knowledge none have shown data supporting one modality over the other [8,14,15]. As such, there is a great need for valid preclinical models in which the mechanism and treatment of these injuries can be properly studied. Many biomechanical studies of thoracolumbar BF have been conducted, testing a variety of modalities to induce and treat BF in an ex vivo setting. Researchers have employed methods such as impacting spinal specimens with free-falling weights of various masses [16,17], compressing specimens with materials testing sys- tems (MTS) [18,19], manual surgical destabilization via an osteot- omy or similar method [20,21], or a combination of these methods [22,23]. Furthermore, a number of clinically relevant treatment techniques have been employed to correct these fractures in the lab setting. However, there exists no comprehensive review of the biomechanical literature to the best of the authors’ knowledge that provides a discussion of the various methods of inducing and treating BF ex vivo. As such, the goal of the current study was to perform a comprehensive, systematic review of traumatic BF of the thoracolumbar spine, with a stringent focus on biomechanical studies. Specifically, the aims included: (1) to review the methods used in an ex vivo setting to induce BF in a spinal specimen and (2) to review the treatment techniques studied for traumatic thoraco- lumbar BF in a preclinical, biomechanical setting. http://dx.doi.org/10.1016/j.jocn.2014.05.002 0967-5868/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +1 312 695 6200; fax: +1 312 695 0225. E-mail address: zsmith@nmff.org (Z.A. Smith). Journal of Clinical Neuroscience xxx (2014) xxx–xxx Contents lists available at ScienceDirect Journal of Clinical Neuroscience journal homepage: www.elsevier.com/locate/jocn Please cite this article in press as: Fakurnejad S et al. Biomechanics of thoracolumbar burst fractures: Methods of induction and treatments. J Clin Neurosci (2014), http://dx.doi.org/10.1016/j.jocn.2014.05.002