title: Risk Factors of Chronic Subdural Hematoma Progression after Conservative Management of Cases with Initially Acute Subdural Hematoma.
abstract: OBJECTIVE
  Acute subdural hematoma (ASDH) patients are treated conservatively or surgically according to the guidelines for surgical treatment. Many patients with thin ASDH and mild neurologic deficit are managed conservatively, but sometimes aggravation of thin ASDH to chronic subdural hematoma (CSDH) results in exacerbated clinical symtoms and consequently requires surgery. The aim of this study is to evaluate risk factors that indicate progression of initially non-operated ASDH to CSDH.
  
  
  METHODS
  We divided 177 patients, presenting with ASDH (managed conservatively initially) between January 2008 to December 2013, into two groups; 'CSDH progression group' (n=16) and 'non-CSDH progression group' (n=161). Patient's data including age, sex, past medical history, medication were collected and brain computed tomography was used for radiologic analysis.
  
  
  RESULTS
  Our data demonstrated that no significant intergroup difference with respect to age, sex ratio, co-morbid conditions, medication history, ischemic heart disease, liver disease and end-stage renal disease was found. However, Hounsfield unit (hematoma density) and mixed density was higher in the 'ASDH progression group' (67.50±7.63) than in the 'non-CSDH progression group' (61.53±10.69) (p=0.031). Midline shifting and hematoma depth in the 'CSDH progression group' were significantly greater than the 'non-CSDH progression group' (p=0.067, p=0.005).
  
  
  CONCLUSIONS
  Based on the results of this study, the risk factors that are related to progression of initially non-operated ASDH to CSDH are higher Hounsfield unit and hematoma depth. Therefore, we suggest that ASDH patients, who have bigger hematoma depth and higher Hounsfield unit, should be monitored and managed carefully during the follow-up period.
authors.affiliation: Department of Neurosurgery, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Jong Joo
authors.initials: JJ
authors.lastname: Lee
authors.affiliation: Department of Neurosurgery, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Yusam
authors.initials: Y
authors.lastname: Won
authors.affiliation: Department of Neurosurgery, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Taeyoung
authors.initials: T
authors.lastname: Yang
authors.affiliation: Department of Neurosurgery, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Sion
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Chun-Sik
authors.initials: CS
authors.lastname: Choi
authors.affiliation: Department of Neurosurgery, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Korea.
authors.forename: Jaeyoung
authors.initials: J
authors.lastname: Yang
keywords: Hematoma, subdural, acute; Hematoma, subdural, chronic; Progression; Risk factors