title: L5-S1 disc degeneration and the anatomic parameters of the iliac crest: imaging study.
abstract: OBJECTIVE
  To evaluate the relationship between height ratio of the iliac crest to L4 (HR), width ratio of the iliac crest to L4 (WR) and L5-S1 disc degeneration.
  
  
  METHODS
  On T2-weighted sagittal images of the 50 randomly selected patients, two observers graded L5-S1 discs and some other parameters were measured. Then, relative signal intensity (RSI) of the L5-S1 nucleus pulposus was calculated. On anteroposterior and lateral radiographs of the same 50 patients' lumbar spine, the parameters such as the height of the iliac crest were measured and then HR and WR were calculated. Finally, HR, WR and the percentage of the sROM of L5-S1 in L1-S1 segments of the other 51 randomly selected patients were calculated.
  
  
  RESULTS
  Positive correlations were found between HR, WR and RSI of the L5-S1 disc. Negative correlations were found between HR, WR and modified Pfirrmann scores of L5-S1 nucleus pulposus. A statistically significant negative correlation was found between HR and the percentage of sROM of L5-S1 in L1-S1 segments.
  
  
  CONCLUSIONS
  Low HR and (or) WR were the risk factors for L5-S1 disc degeneration. High HR could reduce the percentage of sROM of L5-S1 in L1-S1 segments and high HR and (or) WR could reduce the incidence of L5-S1 disc degeneration.
authors.affiliation: Department of Orthopaedic Surgery, Second Affiliated Hospital of Wenzhou Medical University, 109 Xueyuan Xi Road, Wenzhou, 325027, Zhejiang, China.
authors.forename: Yong-Li
authors.initials: YL
authors.lastname: Wang
authors.affiliation: Department of Orthopaedic Surgery, Second Affiliated Hospital of Wenzhou Medical University, 109 Xueyuan Xi Road, Wenzhou, 325027, Zhejiang, China.
authors.forename: Xiang-Yang
authors.initials: XY
authors.lastname: Wang
authors.affiliation: Radiology Department, Second Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Bi-Dong
authors.initials: BD
authors.lastname: Fang
authors.affiliation: Department of Orthopaedic Surgery, Second Affiliated Hospital of Wenzhou Medical University, 109 Xueyuan Xi Road, Wenzhou, 325027, Zhejiang, China.
authors.forename: Yong-Long
authors.initials: YL
authors.lastname: Chi
authors.affiliation: Department of Orthopaedic Surgery, Second Affiliated Hospital of Wenzhou Medical University, 109 Xueyuan Xi Road, Wenzhou, 325027, Zhejiang, China.
authors.forename: Hua-Zi
authors.initials: HZ
authors.lastname: Xu
authors.affiliation: Institute of Digitized Medicine, Wenzhou Medical University, Wenzhou, Zhejiang, China.
authors.forename: Li-Jun
authors.initials: LJ
authors.lastname: Wu
authors.affiliation: Department of Orthopaedic Surgery, Second Affiliated Hospital of Wenzhou Medical University, 109 Xueyuan Xi Road, Wenzhou, 325027, Zhejiang, China. zhongkelin@163.com.
authors.forename: Zhong-Ke
authors.identifier: http://orcid.org/0000-0003-4627-5520
authors.initials: ZK
authors.lastname: Lin
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007085:Ilium / Q000000981:diagnostic imaging*; D015994:Incidence; D055959:Intervertebral Disc Degeneration / Q000175:diagnosis / Q000473:pathology*; D008159:Lumbar Vertebrae / Q000473:pathology*; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Disc degeneration; Iliac crest; L5–S1 disc; MRI; Radiograph