title: Sagittal alignment of the spine and pelvis in the presence of L5-s1 isthmic lysis and low-grade spondylolisthesis.
abstract: METHODS
  A radiographic study of 82 patients with L5-S1 spondylolysis or spondylolisthesis of less than 50% displacement of L5 on S1.
  
  
  OBJECTIVE
  To measure and describe the sagittal alignment of the spine and pelvis in patients with spondylolysis before the development of a large secondary deformity associated with progression of the spondylolisthesis.
  
  
  BACKGROUND
  Several publications have addressed the alignment of the spine and pelvis as an important factor in the occurrence, symptomatology, progression, and treatment of spondylolysis and spondylolisthesis. To our knowledge, this is the first report to systematically document the native sagittal alignment of affected patients and compare them to a large control population.
  
  
  METHODS
  The sagittal alignment in this cohort of 82 patients was compared with a control population of 160 patients without symptoms of back pain or radiographic abnormalities of the spine and pelvis that was the subject of a previous study.
  
  
  RESULTS
  Patients with spondylolysis and low-grade spondylolisthesis demonstrate increased pelvic incidence, increased lumbar lordosis, but less segmental extension between L5 and S1 than in a normal population.
  
  
  CONCLUSIONS
  These data suggest that differences in the sagittal alignment of the spine and pelvis may influence the biomechanical environment that results in the development of spondylolysis and progressive spondylolisthesis.
authors.affiliation: Department of Orthopedic Surgery, Centre Des Massues, Lyon, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Roussouly
authors.forename: Sohrab
authors.initials: S
authors.lastname: Gollogly
authors.forename: Eric
authors.initials: E
authors.lastname: Berthonnaud
authors.forename: Hubert
authors.initials: H
authors.lastname: Labelle
authors.forename: Mark
authors.initials: M
authors.lastname: Weidenbaum
mesh_terms: D000293:Adolescent; D000328:Adult; D015331:Cohort Studies; D006801:Humans; D008159:Lumbar Vertebrae / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D008953:Models, Anatomic; D010388:Pelvis / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D011859:Radiography; D012189:Retrospective Studies; D012447:Sacrum / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D013131:Spine / Q000033:anatomy & histology / Q000000981:diagnostic imaging; D013168:Spondylolisthesis / Q000000981:diagnostic imaging / Q000473:pathology*