title: Bone Turnover Markers as a New Predicting Factor for Nonunion After Spinal Fusion Surgery.
abstract: METHODS
  Retrospective observational study.
  
  
  OBJECTIVE
  We investigated whether bone turnover markers could be a useful indicator for prediction of nonunion.
  
  
  BACKGROUND
  Nonunion is a major complication of lumbar spinal fusion surgery. The involvement of bone turnover in the process of bony union in spinal fusion surgery is, however, poorly understood.
  
  
  METHODS
  Of the 74 patients analyzed, 13 were diagnosed with nonunion. We evaluated the significance of the following risk factors: age, sex, number of fused segments, serum levels of total alkaline phosphatase, procollagen type 1 amino-terminal propeptide (P1NP), tartrate-resistant acid phosphatase 5b (TRACP-5b), and albumin, and history of diabetes mellitus, cigarette smoking, or alcohol use. We also defined the bone turnover ratio (BTR) as a value that equals serum TRACP-5b concentration divided by serum P1NP concentration to evaluate patients' individual bone turnover balance and investigated the significance of BTR as a risk factor.
  
  
  RESULTS
  Univariate analysis showed that older age, malnutrition, and lower P1NP are risk factors for nonunion. Stepwise logistic regression analysis revealed that in the presence of lower P1NP, higher TRACP-5b becomes a risk factor. Furthermore, we identified BTR as the most significant risk factor for nonunion. The optimum cut-off value of BTR by receiver-operating characteristic curve was 11.74.
  
  
  CONCLUSIONS
  These findings show a relation between bone turnover and nonunion after spinal fusion surgery. The measurement of bone turnover markers could potentially be used to predict nonunion after spinal fusion surgery.
  
  
  METHODS
  4.
authors.affiliation: Department of Orthopaedic Surgery, Graduate School, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Inose
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Yamada
authors.forename: Mieradili
authors.initials: M
authors.lastname: Mulati
authors.forename: Takashi
authors.initials: T
authors.lastname: Hirai
authors.forename: Shuta
authors.initials: S
authors.lastname: Ushio
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Yoshii
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Kato
authors.forename: Shigenori
authors.initials: S
authors.lastname: Kawabata
authors.forename: Atsushi
authors.initials: A
authors.lastname: Okawa
mesh_terms: D000135:Acid Phosphatase / Q000097:blood*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000469:Alkaline Phosphatase / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D016723:Bone Remodeling / Q000502:physiology*; D024042:Collagen Type I / Q000097:blood*; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000379:methods*; D000071681:Tartrate-Resistant Acid Phosphatase / Q000097:blood*; D017211:Treatment Failure
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase