en Gamma Knife Radiosurgery Research <p style="text-align: justify;"><strong>Background & Aim:</strong> Post-traumatic subdural hygroma can be associated with subdural or epidural hematoma. It is usually silent with&nbsp;mild symptoms and often disappears spontaneously needing no treatment. In this study, we investigated the clinical characteristics of&nbsp;subdural hygroma in patients with traumatic brain injury.<br> <strong>Methods & Materials/Patients:</strong> In a cross-sectional study, data of 3244 patients with head injury admitted to Poursina hospital were&nbsp;collected through a questionnaire which included variables of age, sex, GCS on admission, mechanism of trauma, accompanying cranial&nbsp;injuries and treatments, unilateral/bilateral hygroma, and size, volume, and location of hygroma. Finally, the data were analyzed using&nbsp;SPSS (version 19) and descriptive statistics.<br> <strong>Results:</strong> In this study, 81.8% of patients were men and 18.2% women with mean age of 60.91&plusmn;26.07 years old. Accident was the most&nbsp;common cause (63.6%) and the severity of head injury was mild in majority of patients (63.6%) according to GCS. The average time of&nbsp;diagnosis was 10.4 days after the head injury was located in frontal (36.4%) and fronto-parietal (36.4%) areas in most patients. Most of&nbsp;the accompanying cranial injuries were brain contusion (36.4%) and subarachnoid hemorrhage (27.3%). The majority of patients (81.8%)&nbsp;underwent conservative treatment and showed a favorable outcome (63.6%).<br> <strong>Conclusion:</strong> Most of the times, subdural hygroma is observed in older people and disappears over time with vanishing clinical symptoms.&nbsp;Most cases have to undergo conservative treatment.</p> Subdural Hygroma, Head Injury, Conservative Treatment 15 17 http://irjns.org/browse.php?a_code=A-10-88-4&slc_lang=en&sid=1 Shahrokh Yousefzadeh-Chabok شاهرخ یوسف زاده چابک 10031947532846003176 10031947532846003176 No Neuroscience Research Center, Department of Neurosurgery, Poursina Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran Ali Babaei Jandaghi علی بابایی جندقی 10031947532846003177 10031947532846003177 No Neuroscience Research Center, Department of Neurosurgery, Poursina Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran Ehsan Kazemnejad-Leili احسان کاظم نژاد لیلی 10031947532846003178 10031947532846003178 No Guilan Road Trauma Research Center, Department of Neurosurgery, Poursina Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran Leila Kouchakinejad-Eramsadati لیلا کوچکی نژاد ارم ساداتی 10031947532846003179 10031947532846003179 No Guilan Road Trauma Research Center, Department of Neurosurgery, Poursina Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran Marieh Hosseinpour ماریه حسین پور bak-sou@hotmail.com 10031947532846003180 10031947532846003180 Yes Neuroscience Research Center, Department of Neurosurgery, Poursina Hospital, School of Medicine, Guilan University of Medical Sciences, Rasht, Iran