title: Value of routine early post-operative computed tomography in determining short-term functional outcome after drainage of chronic subdural hematoma: An evaluation of residual volume.
abstract: BACKGROUND
  Computed tomography (CT) scans are widely used in managing chronic subdural hematoma (CSDH). Factors that determine early post-operative volume have not been examined. The value of routine early post-operative residual volume have not been evaluated. Our study aims to compare pre-operative and early post-operative CT findings to determine the factors affecting residual hematoma and evaluate if early post-operative CT scans are useful in the management of CSDH.
  
  
  METHODS
  Forty-three patients who underwent burr hole drainage of unilateral CSDH from August 2006 to January 2013 and had routine post-operative CT scans within 48 hours of surgery were selected. Data regarding age, sex, neurological deficit, Glasgow Coma Scale (GCS), pre-existing medical conditions, use of antiplatelets or anticoagulation, operative time, usage of drains, and number of burr holes were obtained. The pre-operative CSDH volume, CSDH density, and midline shift were measured. Residual volume was calculated from early post-operative CT scans. Clinical outcome was evaluated with Glasgow Outcome Scale (GOS) at the time of discharge. Statistical analysis was performed to look for correlation between the pre-operative factors and residual volume, and the residual volume and GOS.
  
  
  RESULTS
  Pre-operative volume was found to correlate significantly with post-operative residual volume. There was no significant correlation between all other pre-operative factors and residual volume. There was also no correlation between residual volume and GOS at discharge.
  
  
  CONCLUSIONS
  Routine post-operative CT brain for burr hole drainage of CSDH may be unnecessary in view of the good predictive value of pre-operative volume, and also because it is not predictive of the clinical outcome.
authors.affiliation: Department of Neurosurgery, Changi General Hospital, 2 Simei Street 3, Singapore.
authors.forename: Hui Yu
authors.initials: HY
authors.lastname: Ng
authors.affiliation: National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore.
authors.forename: Wai Hoe
authors.initials: WH
authors.lastname: Ng
authors.affiliation: National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore.
authors.forename: Nicolas K K
authors.initials: NK
authors.lastname: King
keywords: Chronic; hematoma; outcome; post-operative computed tomography; residual volume; subdural