title: Efficacy and safety of subdural drains after burr-hole evacuation of chronic subdural hematomas: systematic review and meta-analysis of randomized controlled trials.
abstract: OBJECTIVE
  To determine whether the use of a subdural drain after burr-hole evacuation of a chronic subdural hematoma is safe and effective in preventing recurrence and subsequent operations, and as such improving functional outcomes.
  
  
  METHODS
  The literature search included the following databases: PubMed, the National Institutes of Health/National Library of Medicine, Clinical Trials Registry, CENTRAL (The Cochrane Library), EMBASE, and LILACS. The search was performed in June 2013, and did not have restrictions or filters with regard to language or year of publication. Methodologic quality was assessed through the Jadad's scale. Primary outcomes were recurrence and reoperation rates. Secondary outcomes were functional outcome, mortality, and postoperative complications. Results were presented as pooled Mantel-Haenszel relative risks (RR), with 95% confidence intervals (95% CI).
  
  
  RESULTS
  A total of 7 randomized controlled trials were analyzed. Three studies were classified as high methodologic quality and four as low quality. Pooled RR were symptomatic recurrence (RR 0.51; 95% CI 0.36-0.75), reoperation (RR 0.5; 95% CI 0.34-0.74), poor functional outcome (RR 0.61, 95% CI 0.39-0.98), mortality (RR 0.67, 95% CI 0.37-1.22), and postoperative complications (RR 1.28, 95% CI 0.78-2.11). There was no statistically significant heterogeneity within the outcomes.
  
  
  CONCLUSIONS
  The meta-analysis demonstrates that the insertion of a subdural drain was associated with a statistically significant reduction in the risk of symptomatic recurrence and the requirement for further surgical intervention of chronic subdural hematoma after surgical evacuation. Furthermore, it was associated with statistically significant improvements in both short-term and long-term functional outcome.
authors.affiliation: Health Sciences and Neurosciences Research Group (CISNEURO), Cartagena de Indias, Colombia; Department of Neurosurgery, Faculty of Medicine, Universidad de Cartagena, Cartagena de Indias, Colombia. Electronic address: alcalag@egresado.uninorte.edu.co.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Alcalá-Cerra
authors.affiliation: Department of Neurosurgery, Harvard Medical School, Massachusetts General Hospital, Boston, Massachusetts, USA; School of Clinical Medicine, University of Cambridge, Addenbrooke's Hospital, Cambridge, United Kingdom.
authors.forename: Adam M H
authors.initials: AM
authors.lastname: Young
authors.affiliation: Health Sciences and Neurosciences Research Group (CISNEURO), Cartagena de Indias, Colombia.
authors.forename: Luis Rafael
authors.initials: LR
authors.lastname: Moscote-Salazar
authors.affiliation: Health Sciences and Neurosciences Research Group (CISNEURO), Cartagena de Indias, Colombia.
authors.forename: Angel
authors.initials: A
authors.lastname: Paternina-Caicedo
mesh_terms: D003399:Craniotomy / Q000379:methods*; D004322:Drainage / Q000379:methods*; D020200:Hematoma, Subdural, Chronic / Q000601:surgery*; D006801:Humans; D019635:Neurosurgical Procedures / Q000379:methods*; D016032:Randomized Controlled Trials as Topic; D016896:Treatment Outcome
keywords: Burr-hole; Chronic subdural hematoma; Closed-system drainage; Recurrence; Reoperation