title: The utility of erythrocyte sedimentation rate values and white blood cell counts after spinal deformity surgery in the early (≤3 months) post-operative period.
abstract: OBJECTIVE
  The erythrocyte sedimentation rate (ESR) and white blood cell (WBC) count are frequently obtained in the work-up of post-operative fever. However, their diagnostic utility depends upon comparison with normative peri-operative trends which have not yet been described. The purpose of this study is to define a range of erythrocyte sedimentation rates and white blood cell counts following spinal instrumentation and fusion in non-infected patients.
  
  
  METHODS
  Seventy-five patients underwent spinal instrumentation and fusion. The erythrocyte sedimentation rate and white blood cell count were recorded pre-operatively, at 3 and 7 days post-operatively, and at 1 and 3 months post-operatively.
  
  
  RESULTS
  Both erythrocyte sedimentation rate and white blood cell count trends demonstrated an early peak, followed by a gradual return to normal. Peak erythrocyte sedimentation rates occurred within the first week post-operatively in 98% of patients. Peak white blood cell counts occurred with the first week in 85% of patients. In the absence of infection, the erythrocyte sedimentation rate was abnormally elevated in 78% of patients at 1 month and in 53% of patients at 3 months post-operatively. The white blood cell count was abnormally elevated in only 6% of patients at 1 month post-operatively. Longer surgical time was associated with elevated white cell count at 1 week post-operatively. The fusion of more vertebral levels had a negative relationship with elevated erythrocyte sedimentation rate at 1 week post-operatively. The anterior surgical approach was associated with significantly lower erythrocyte sedimentation rate at 1 month post-operatively and with lower white cell count at 1 week post-operatively.
  
  
  CONCLUSIONS
  In non-infected spinal fusion surgeries, erythrocyte sedimentation rates are in the abnormal range in 78% of patients at 1 month and in 53% of patients at 3 months post-operatively, suggesting that the erythrocyte sedimentation rate is of limited diagnostic value in the early post-operative period.
authors: Department of Orthopedic Surgery, Washington University, Campus Box 8233, 660 South Euclid Avenue, St. Louis, MO 63110 USA.
authors: Margaret G
authors: MG
authors: Kuhn
authors: Lawrence G
authors: LG
authors: Lenke
authors: Keith H
authors: KH
authors: Bridwell
authors: June C
authors: JC
authors: O'Donnell
authors: Scott J
authors: SJ
authors: Luhmann
keywords: Leukocyte count; Sedimentation rate; Spinal fusion; Spinal instrumentation; Surgical site infection