title: A Reliable Grading System for Prediction of Chronic Subdural Hematoma Recurrence Requiring Reoperation After Initial Burr-Hole Surgery.
abstract: BACKGROUND
  There is no widely adopted grading system for the prediction of postoperative recurrence requiring reoperation (RrR) in patients with chronic subdural hematoma (CSDH).
  
  
  OBJECTIVE
  We developed a CSDH grading system to predict RrR based on predictive characteristics that can be objectively assessed at the time of first presentation and initial surgery.
  
  
  METHODS
  Prospectively collected data from 107 consecutive surgical patients with CSDH were reviewed. Predictors of RrR were identified via logistic and lasso regression analyses. A prognostic CSDH grading system was proposed, with the weighing of predictors based on strength of association. The scoring system was then applied to the same set of patients in our database for internal validation.
  
  
  RESULTS
  The strongest predictors of RrR were an isodense or hyperdense lesions and laminar or separated lesions, and a postoperative CSDH cavity volume greater than 200 mL. The moderate predictors of RrR were a postoperative CSDH cavity volume of 80 to 200 mL and a preoperative CSDH volume greater than 130 mL. According to the prognostic CSDH grading system, no patients with a score of 0 points had RrR. RrR was observed in 6% of patients with a score of 1 to 2 points, 30% of patients with a score of 3 to 4 points, and 63% of patients with a score of 5 points (ie, the maximum score). The rate of RrR increased steadily with increases in the prognostic CSDH grading score (P < .001).
  
  
  CONCLUSIONS
  The prognostic CSDH grading system is an applicable tool for RrR risk stratification in patients with CSDH.
authors.affiliation: Department of Neurosurgery, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
authors.forename: Milo
authors.initials: M
authors.lastname: Stanišic
authors.affiliation: Oslo Centre of Biostatistics and Epidemiology, Research Support Service, Oslo University Hospital, Oslo, Norway.
authors.forename: Are Hugo
authors.initials: AH
authors.lastname: Pripp
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D020200:Hematoma, Subdural, Chronic / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000009:adverse effects*; D011183:Postoperative Complications / Q000209:etiology; D011379:Prognosis; D011446:Prospective Studies; D012008:Recurrence; D012086:Reoperation / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods; D055815:Young Adult
keywords: Chronic subdural hematoma; Prognostic grading system