title: Early fracture of the sacrum or pelvis: an unusual complication after multilevel instrumented lumbosacral fusion.
abstract: METHODS
  A retrospective review of a series of cases with a complication of instrumented lumbosacral fusion.
  
  
  OBJECTIVE
  To present a previously undescribed complication, early sacral or pelvic stress fracture, after instrumented lumbosacral fusion and to identify the risk factors associated with this complication.
  
  
  BACKGROUND
  There are a number of well-described complications of instrumented lumbosacral fusion, including delayed stress fracture of the pelvis. Early sacral or pelvic stress fracture after instrumented lumbosacral fusion has not been previously reported, to the authors' knowledge.
  
  
  METHODS
  The authors present three cases of early stress fracture occurring at 2-4 weeks after surgery in patients who underwent instrumented multilevel lumbosacral fusions for degenerative lumbosacral disease.
  
  
  RESULTS
  Two patients had sacral fracture, which to the authors' knowledge, has not been previously reported. Risk factors included lumbosacral instrumentation and fusion, osteoporosis in elderly women, and iliac crest bone graft procurement. All patients were treated conservatively, with restricted ambulation and gradual return to activity.
  
  
  CONCLUSIONS
  This complication can cause significant morbidity and a delay in the patient's return to function. A better understanding of the related biomechanical forces and preoperative risk factors may identify patients at risk and may aid in surgical planning and in expectations of postoperative recovery.
authors.affiliation: Department of Orthopedic Surgery, Lenox Hill Hospital, New York, New York, USA.
authors.forename: V
authors.initials: V
authors.lastname: Mathews
authors.forename: S E
authors.initials: SE
authors.lastname: McCance
authors.forename: P F
authors.initials: PF
authors.lastname: O'Leary
mesh_terms: D000368:Aged; D005260:Female; D015775:Fractures, Stress / Q000209:etiology*; D006801:Humans; D008161:Lumbosacral Region; D010388:Pelvis / Q000293:injuries*; D011183:Postoperative Complications / Q000209:etiology*; D012189:Retrospective Studies; D012307:Risk Factors; D012447:Sacrum / Q000293:injuries*; D013123:Spinal Fusion / Q000379:methods*