Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 57 6 2019 11 17 385 394 Mahdi Sharif-Alhoseini Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran. Fariba Vahedi Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran. Mahmoud Omidbeigi Skull Base Research Center, Loghman Hakim Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Marzieh Sharifi Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran. Zahra Hassannejad Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran. Shayan Abdollah Zadegan Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran. Motahareh Rezvan Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran. Mona Mokhatab Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran. Kiavash Sajadi Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran. Aida Shakouri-Motlagh Department of Chemical and Biomolecular Engineering, University of Melbourne, Melbourne, Australia. Farhad Shokraneh Cochrane Schizophrenia Group, Institute of Mental Health, University of Nottingham, Nottingham, UK. Alexander R. Vaccaro Department of Orthopaedic Surgery, The Rothman Institute, Thomas Jefferson University, Philadelphia, USA. Vafa Rahimi Movaghar Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences, Tehran, Iran. ANDBrain and Spinal Cord Injury Research Center, Tehran University of Medical Sciences, Tehran, Iran. AND Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran . 2019 01 13 2019 09 08 There are limited data on the lesion volume changes following spinal cord injury (SCI). In this study, a meta-analysis was performed to evaluate the volume size changes of the injured spinal cord over time among animal studies in traumatic SCI. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a comprehensive electronic search of English literature of PubMed and EMBASE databases from 1946 to 2015 concerning the time-dependent changes in the volume of the spinal cord following mechanical traumatic SCI. A hand-search was also performed for non-interventional, non-molecular, and non-review studies. Quality appraisal, data extraction, qualitative and quantitative analyses were performed afterward. Of 11,561 articles yielded from electronic search, 49 articles were assessed for eligibility after reviewing of titles, abstracts, and references. Ultimately, 11 articles were eligible for quantitative synthesis. The ratio of lesion volume to spinal cord total volume increased over time. Avascularity appeared in spinal cord 4 hours after injury. During the first week, the spinal subarachnoid space decreased. The hemorrhagic lesion size peaked in 1 week and decreased thereafter. Significant loss of gray and white matter occurred from day 3 with a slower progression of white matter damage. Changes of lesion extent over time is critical in pathophysiologic processes after SCI. Early avascularity, rapid loss of gray matter, slow progression of white matter damage, and late cavitation are the pathophysiologic key points of SCI, which could be helpful in choosing the proper intervention on a timely basis. https://acta.tums.ac.ir/index.php/acta/article/view/7684 https://acta.tums.ac.ir/index.php/acta/article/download/7684/5279