title: Sagittal Pelvic Radius in Low-Grade Isthmic Lumbar Spondylolisthesis of Chinese Population.
abstract: OBJECTIVE
  To investigate the variation of pelvic radius and related parameters in low-grade isthmic lumbar spondylolisthesis.
  
  
  METHODS
  Seventy-four patients with isthmic lumbar spondylolisthesis and 47 controls were included in this study. There were 17 males and 57 females between 30 and 66 years of age, including 30 with grade I slippages and 44 grade II slippages; diseased levels included 34 cases on L4 and 40 cases on L5. Thoracic kyphosis (TK), the pelvic radius (PR), the pelvic angle (PA), pelvic morphology (PR-S1), and total lumbopelvic lordosis (PR-T12) were assessed from radiographs.
  
  
  RESULTS
  Statistically significant differences were found for the PA, PR-T12, and PR-S1 (24.5±6.6°, 83.7±9.8°, and 25.4±11.2°, respectively) of the patients with spondylolisthesis and the healthy volunteers (13.7±7.8°, 92.9±9.2°, and 40.7±8.9°, respectively). The TK/PR-T12 ratios were between 0.15 and 0.75. However, there were no differences in all the parameters between the L4 and L5 spondylolysis subgroups (p>0.05). The TK and PR-S1 of grade II were less than grade I, but the PA was greater. The PR-T12 of female patients were less than male patients, but the PA was greater (p<0.05).
  
  
  CONCLUSIONS
  Pelvic morphology differed in patients with low-grade isthmic lumbar spondylolisthesis compared to controls. Gender and the grade of slippage impacted the sagittal configuration of the pelvis, but the segment of the vertebral slip did not. Overall, the spine of those with spondylolisthesis remains able to maintain sagittal balance despite abnormal pelvic morphology.
authors.affiliation: Department of Spinal Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Department of Spinal Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China.
authors.forename: Cai-Liang
authors.initials: CL
authors.lastname: Shen
authors.affiliation: Department of Spinal Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China.
authors.forename: Ren-Jie
authors.initials: RJ
authors.lastname: Zhang
authors.affiliation: Department of Spinal Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China.
authors.forename: Da-Wei
authors.initials: DW
authors.lastname: Cheng
authors.affiliation: Department of Spinal Surgery, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China.
authors.forename: Fu-Long
authors.initials: FL
authors.lastname: Dong
authors.affiliation: Department of Radiology, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
keywords: Isthmic lumbar spondylolisthesis; Pelvic radius; Sagittal balance