Medical Journal of the Islamic Republic Of Iran

en Risk Factors of Chronic Subdural Hematoma Recurrence: A Systematic Review Neurology Neurology Systematic Review Background: Although various factors have been proposed in connection with the recurrence of chronic subdural hematoma (cSDH), the results obtained in previous studies have not been consistent. This study was conducted to describe the risk factors for cSDH recurrence, drawing upon the current literature, and to provide an integrative framework that links these factors with underlying biological mechanisms.    Methods: In December 2024, a systematic literature search was performed using the Scopus, Web of Science, PubMed, and Embase electronic databases. The retrieved records were screened against eligibility criteria and selected in 2 stages. The Newcastle-Ottawa Scale (NOS) was utilized for bias assessment, and the PRISMA (Preferred Reporting Items for Systematic Reviews) checklist was employed to assess the methodological rigor and reliability of the selected studies and their findings.    Results: After applying the inclusion and exclusion criteria, 61 studies were retained for the systematic review. The principal risk factors associated with the recurrence of cSDH were elucidated and correlated with underlying pathophysiological processes. Lower Glasgow Coma Scale (GCS) scores and elevated postoperative neutrophil counts indicate increased inflammation. The use of antiplatelet and anticoagulant agents reflects coagulation dysfunction, which raises the risk of rebleeding. Additional factors such as male sex, older age, larger hematoma size, and shorter drainage duration relate to anatomical and clinical vulnerability. Radiological signs, such as high hematoma density and midline shift, support the role of structural brain changes. Comorbidities, including diabetes and hypertension, exacerbate vascular fragility, increasing recurrence risk. Early detection, effective postoperative drainage, and higher serum HDL levels contribute to a reduced risk of recurrence.    Conclusion: cSDH recurrence results from the complex interplay of biological processes, including inflammation, coagulation dysfunction, and structural brain changes, with clinical risk factors. Recognizing and targeting these integrated pathways is crucial for improving prevention and management strategies.   Prevalence, Risk factors, Recurrence, Subdural Hematoma 1099 1123 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-9604-1&slc_lang=en&sid=1 SeyedAhmad SeyedAlinaghi s_a_alinaghi@yahoo.com 200319475328460093771 200319475328460093771 No Iranian Research Center for HIV/AIDS, Iranian Institute for Reduction of High Risk Behaviors, Tehran University of Medical Sciences, Tehran, Iran Esmaeil Mehraeen es.mehraeen@gmail.com 200319475328460093772 200319475328460093772 No Department of Health Information Technology, Khalkhal University of Medical Sciences, Khalkhal, Iran Farid Farahani Rad farid.f.rad@gmail.com 200319475328460093773 200319475328460093773 No School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Farzad Fayedeh farzadfayedeh@gmail.com 200319475328460093774 200319475328460093774 No Student research committee, Birjand University of Medical Sciences, Birjand, Iran Iman Amiri Fard amirifard.iman@gmail.com 200319475328460093775 200319475328460093775 No Iranian Research Center for HIV/AIDS, Iranian Institute for Reduction of High Risk Behaviors, Tehran University of Medical Sciences, Tehran, Iran Haleh Siami Haleh.siami@gmail.com 200319475328460093776 200319475328460093776 No School of Medicine, Islamic Azad University, Tehran, Iran Elham Emamgholizade Baboli elhamegzb75@gmail.com 200319475328460093777 200319475328460093777 No Department of Anaesthesiology and Operating Room, School of Allied Medical Sciences, Babol University of Medical Sciences, Babol, Iran Ayoob Molla Ayoob.dpt87@gmail.com 200319475328460093778 0009-0007-2959-6222 No School of Medicine, Bushehr University of Medical Sciences, Bushehr, Iran Esmaeil Fakharian fakharianesmaeil@gmail.com 200319475328460093779 200319475328460093779 No Trauma Research Center, Department of Neurosurgery, Kashan University of Medical Sciences, Kashan, Iran Abbas Tafakhori abbas.tafakhori@gmail.com 200319475328460093780 200319475328460093780 No Iranian Center of Neurological Research, Neuroscience Institute, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran Negar Mousavi Ejarestaghi negarmousavi.ej@gmail.com 200319475328460093781 200319475328460093781 No School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Sahar Nooralioghli Parikhani Sahar.nurse91@gmail.com 200319475328460093782 200319475328460093782 No School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Negin Esmaeili neginesmaeili13781222@gmail.com 200319475328460093783 200319475328460093783 No School of Allied Medical Sciences, Tabriz University of Medical Sciences, Tabriz, Iran Soudabeh Yarmohammadi yarmohammadi_s@kaums.ac.ir 200319475328460093784 200319475328460093784 Yes Trauma Research Center, Kashan University of Medical Sciences, Kashan, Iran