title: Factors predicting hospital stay, operative time, blood loss, and transfusion in patients undergoing revision posterior lumbar spine decompression, fusion, and segmental instrumentation.
abstract: METHODS
  A retrospective chart review was conducted for 112 patients who underwent revision posterior lumbar spine decompression, fusion, and segmental instrumentation.
  
  
  OBJECTIVE
  To ascertain factors predicting hospital stay, operative time, blood loss, and transfusion in patients undergoing revision posterior lumbar spine decompression, fusion, and segmental instrumentation.
  
  
  BACKGROUND
  Posterior lumbar spine decompression and fusion with segmental instrumentation is a common procedure in the treatment of degenerative lumbar spine disorders. Many patients undergoing this procedure have had previous lumbar spine surgery, yet little is known about the factors predicting hospital stay, operative time, blood loss, and transfusion.
  
  
  METHODS
  The charts of 112 patients (53 men and 59 women) with degenerative lumbar spinal stenosis who underwent revision surgery from March 1992 to June 1999 were reviewed. Their average age was 54 years (range, 27-84 years). All the surgeries included decompression and fusion with segmental instrumentation. The patients' demographics, comorbid conditions, factors related to previous lumbar spine surgery, diagnosis, number of levels fused, and preoperative hemoglobin and hematocrit were collected and used as the independent variables. Multiple regression analysis was used to ascertain factors predicting length of hospital stay, operative time, intraoperative blood loss, and transfusion.
  
  
  RESULTS
  The mean length of hospital stay was 6 +/- 2.4 days, the operative time 280 +/- 62 minutes, the estimated intraoperative blood loss 1073 +/- 716 mL, and the total volume of blood transfused 1.04 +/- 1.17 U. For 63% of the patients, a blood transfusion was needed. Increasing age was the significant predictor for hospital stay (P < 0.001). The factors predicting operative time were number of levels fused (P < 0.001), diagnosis of degenerative scoliosis (P < 0.05), and excessive body weight (P < 0.01). The factors predicting intraoperative blood loss were number of levels fused (P < 0.01), body weight (P < 0.001), and high preoperative hemoglobin (P < 0.001). Both logistic and linear regression analysis showed that the factors predicting blood transfusion were number of levels fused (P < 0.01), age (P < 0.05), and low preoperative hemoglobin (P < 0.001). Other factors associated with hospital stay and blood transfusion were unemployment associated with three or more comorbid conditions and complications. The women had less intraoperative blood loss (P < 0.01), but received more transfused blood than the men (P < 0.01).
  
  
  CONCLUSIONS
  Number of levels fused and age seem to be the most significant factors predicting hospital stay, operative time, intraoperative blood loss, and transfusion in patients undergoing revision posterior lumbar spine decompression, fusion, and segmental instrumentation.
authors.affiliation: Spine Service, Hospital for Special Surgery, Weill Medical College of Cornell University, New York, New York, USA. zhengf@hss.edu
authors.forename: Fengyu
authors.initials: F
authors.lastname: Zheng
authors.forename: Frank P
authors.initials: FP
authors.lastname: Cammisa
authors.forename: Harvinder S
authors.initials: HS
authors.lastname: Sandhu
authors.forename: Federico P
authors.initials: FP
authors.lastname: Girardi
authors.forename: Safdar N
authors.initials: SN
authors.lastname: Khan
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D016063:Blood Loss, Surgical / Q000706:statistics & numerical data*; D001803:Blood Transfusion / Q000706:statistics & numerical data*; D015897:Comorbidity; D019299:Decompression, Surgical / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D007432:Intraoperative Period / Q000706:statistics & numerical data; D007902:Length of Stay / Q000706:statistics & numerical data*; D016015:Logistic Models; D008161:Lumbosacral Region; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D012086:Reoperation / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012737:Sex Factors; D013123:Spinal Fusion / Q000706:statistics & numerical data*; D013130:Spinal Stenosis / Q000601:surgery*