title: Predictors of rapid spontaneous resolution of acute subdural hematoma.
abstract: OBJECTIVE
  Acute subdural hematoma (ASDH) usually requires emergency surgical decompression, but rare cases exhibit rapid spontaneous resolution. The aim of this retrospective study was to identify factors predictive of spontaneous ASDH resolution.
  
  
  METHODS
  A total of 366 consecutive patients with ASDH treated between January 2006 and September 2012 were identified in our hospital database. Patients with ASDH clot thickness >10mm in the frontoparietotemporal region and showing a midline shift >10mm on the initial computed tomography (CT) scan were divided into two groups according to subsequent spontaneous resolution. Univariate and multivariate logistic regression analyses were used to identify factors predictive of rapid spontaneous ASDH resolution.
  
  
  RESULTS
  Fifty-six ASDH patients met study criteria and 18 demonstrated rapid spontaneous resolution (32%). Majority of these patients were not operated because of poor prognosis/condition and in accordance to family wishes. Univariate analysis revealed significant differences in use of antiplatelet agents before head injury and in the incidence of a low-density band between the hematoma and inner wall of the skull bone on the initial CT. Use of antiplatelet agents before head injury (OR 19.6, 95% CI 1.5-260.1, p=0.02) and the low-density band on CT images (OR 40.3, 95% CI 3.1-520.2, p=0.005) were identified as independent predictive factors by multivariate analysis.
  
  
  CONCLUSIONS
  Our analysis suggested that use of antiplatelet agents before head injury and a low-density band between the hematoma and inner skull bone on CT images (indicative of cerebrospinal fluid infusion into the subdural space) increase the probability of rapid spontaneous resolution.
authors.affiliation: Department of Neurosurgery, National Hospital Organization Kumamoto Medical Center, 1-5, Ninomaru, Chuo-ku, Kumamoto 860-0008, Japan; Department of Neurosurgery, Faculty of Life Sciences, Kumamoto University School of Medicine, 1-1-1, Honjo, Kumamoto, Kumamoto 861-8556, Japan. Electronic address: schwarz_k1216@yahoo.co.jp.
authors.forename: Kenji
authors.initials: K
authors.lastname: Fujimoto
authors.affiliation: Department of Neurosurgery, National Hospital Organization Kumamoto Medical Center, 1-5, Ninomaru, Chuo-ku, Kumamoto 860-0008, Japan.
authors.forename: Tadahiro
authors.initials: T
authors.lastname: Otsuka
authors.affiliation: Department of Neurosurgery, National Hospital Organization Kumamoto Medical Center, 1-5, Ninomaru, Chuo-ku, Kumamoto 860-0008, Japan.
authors.forename: Kimio
authors.initials: K
authors.lastname: Yoshizato
authors.affiliation: Department of Neurosurgery, Faculty of Life Sciences, Kumamoto University School of Medicine, 1-1-1, Honjo, Kumamoto, Kumamoto 861-8556, Japan.
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Kuratsu
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000473:pathology / Q000601:surgery; D006259:Craniocerebral Trauma / Q000150:complications; D004632:Emergency Medical Services; D005260:Female; D020199:Hematoma, Subdural, Acute / Q000134:cerebrospinal fluid / Q000473:pathology* / Q000601:surgery; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D011237:Predictive Value of Tests; D011379:Prognosis; D012075:Remission, Spontaneous; D012744:Sex Ratio; D012886:Skull / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed
chemical_list: D010975:Platelet Aggregation Inhibitors
keywords: Acute subdural hematoma; Frontoparietotemporal region; Redistribution of hematoma; Spontaneous resolution