title: Radiographical risk factors for major intraoperative blood loss during laminoplasty in patients with ossification of the posterior longitudinal ligament.
abstract: METHODS
  A retrospective multi-institutional study.
  
  
  OBJECTIVE
  To clarify the distribution of intraoperative blood loss during cervical laminoplasty for ossification of the posterior longitudinal ligament (OPLL), and to identify the radiographical risk factors for the occurrence of major blood loss in patients with OPLL undergoing laminoplasty.
  
  
  BACKGROUND
  The incidence of major intraoperative blood loss during laminoplasty for OPLL is unknown.
  
  
  METHODS
  All patients who underwent cervical laminoplasty for OPLL between April 2005 and March 2008 at 27 institutions across Japan were included in this analysis. We investigated the patients' characteristics and surgical data, and compared the radiographical characteristics of OPLL in patients with and without major blood loss.
  
  
  RESULTS
  The estimated intraoperative blood loss was reported for 545 patients (429 male and 116 female; mean age, 62.7 yr). The mean intraoperative blood loss was 223 g (median, 130 g; range, minimal to 3350 g). Excluding 1 patient with intraoperative vertebral artery injury, major blood loss greater than 500 g was reported in 45 patients (8.3%). Patients with major blood loss were more likely to have neurological complications (5/45 vs. 12/499) and a longer hospital stay (29.5 d vs. 28.8 d) in comparison with those without major blood loss. The occupying ratio of OPLL was greater in the major blood loss group (48.3% vs. 42.2%; P = 0.02). A multivariate analysis revealed an occupying ratio of 60% or greater to be associated with an increased risk of major intraoperative blood loss (odds ratio, 2.4; 95% confidence interval, 1.1-5.3).
  
  
  CONCLUSIONS
  Laminoplasty for OPLL is associated with a risk of major intraoperative blood loss, which can potentially give rise to devastating postoperative complications. An occupying ratio of 60% or greater is a risk factor for major blood loss during laminoplasty in patients with OPLL.
authors.affiliation: Department of Orthopaedic Surgery, Sensory and Motor System Medicine, Surgical Sciences, Graduate School of Medicine, University of Tokyo, Tokyo, Japan. skatou-tky@umin.org
authors.forename: So
authors.initials: S
authors.lastname: Kato
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Chikuda
authors.forename: Atsushi
authors.initials: A
authors.lastname: Seichi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohtsu
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kimura
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Toyama
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016063:Blood Loss, Surgical; D005260:Female; D006801:Humans; D007564:Japan; D007902:Length of Stay; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D019637:Orthopedic Procedures / Q000009:adverse effects* / Q000379:methods; D017887:Ossification of Posterior Longitudinal Ligament / Q000000981:diagnostic imaging / Q000601:surgery*; D011183:Postoperative Complications / Q000209:etiology; D011859:Radiography; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome