Contents lists available at ScienceDirect Clinical Biomechanics journal homepage: www.elsevier.com/locate/clinbiomech Review Biomechanical musculoskeletal models of the cervical spine: A systematic literature review Mina Alizadeh a , Gregory G. Knapik a , Prasath Mageswaran a , Ehud Mendel b , Eric Bourekas c , William S. Marras a, ⁎ a Spine Research Institute, The Ohio State University, 520 Baker Systems, 1971 Neil Avenue, Columbus, OH 43210, USA b Department of Neurological Surgery, The Ohio State University, Columbus, OH 43210, USA c Department of Radiology, The Ohio State University, Columbus, OH 43210, USA ARTICLEINFO Keywords: Computational model Neck EMG Multi-body dynamics Curved muscle model Occupational neck injury ABSTRACT Background: As the work load has been shifting from heavy manufacturing to office work, neck disorders are increasing. However, most of the current cervical spine biomechanical models were created to simulate crash situations. Therefore, the biomechanics of cervical spine during daily living and occupational activities remain unknown. In this effort, cervical spine biomechanical models were systematically reviewed based upon different features including approach, biomechanical properties, and validation methods. Methods: The objective of this review was to systematically categorize cervical spine models and compare the underlying logic in order to identify voids in the literature. Findings: Twenty-twomodelsmetourselectioncriteriaandrevealedseveraltrends:1)Themulti-bodydynamics modeling approach, equipped for simulating impact situations were the most common technique; 2) Straight musclelinesofaction,inversedynamic/optimizationmuscleforcecalculation,Hill-typemusclemodelwithonly active component were typically used in the majority of neck models; and 3) Several models have attempted to validatetheirresultsbycomparingtheirapproachwithpreviousstudies,butmostlywereunabletoprovidetask- specific validation. Interpretation: EMG-driven dynamic model for simulating occupational activities, with accurate muscle geo- metry and force representation, and person- or task-specific validation of the model would be necessary to improve model fidelity. 1. Introduction Neckpainisoneofthethreemostcommonlyreportedcomplaintsof the musculoskeletal system (Trinh et al., 2006). It is estimated that the United States spends around $88Bperyear in direct costs treating pa- tients with low back and neck pain, which is more than the amount spent on treating any other condition save for diabetes and ischemic heart disease (Dieleman et al., 2016). Theeconomiesoftheindustrialworldhaveshiftedinthattheywere dependent on manufacturing but now rely largely on the service sector. Theshifthastransformedthenatureofworkinjuriesanddisability.The high rate of acute and fatal injuries observed at the beginning of the 20th century has been replaced by a sharp increase in the incidence of work-related musculoskeletal disorders such as neck pain (Côté et al., 2008; Vasavada et al., 2015). While low back pain has traditionally been the most common spine-related complaint, more and more pa- tients are presenting with neck and radiating arm pain. Annual pre- valence rates for neck pain have grown to 27–48% and are expected to continue to rise due to growing sedentary life and work style (Côté et al., 2008, 2009). Preliminary evidence shows that occupation and occupational class is highly associated with the risk of neck pain. For instance, according to Côtéetal.,2008,amonghealthcareworkers,the annual prevalence of neck pain ranged from 17% in dentists, 26% in pharmacists and 72% in dental hygienists. Strong associations have been observed between cervical spine myofascial pain to neurological and biomechanical interactions of muscles and neck posture (Hong et al., 2019). The range of motion of the neck and the activities of the cervical muscles appeared to be al- tered in myofascial patients. It has been demonstrated that majority of work-related neck disorders can be caused by head positioning https://doi.org/10.1016/j.clinbiomech.2019.10.027 Received 8 April 2019; Accepted 29 October 2019 ⁎ Corresponding author at: Spine Research Institute, The Ohio State University, Department of Integrated Systems Engineering, 1971 Neil Avenue, 210 Baker Systems Engineering, Columbus, OH 43210, USA. E-mail address: marras.1@osu.edu (W.S. Marras). Clinical Biomechanics 71 (2020) 115–124 0268-0033/ © 2019 Elsevier Ltd. All rights reserved. T