title: The prevalence of tandem spinal stenosis and its characteristics in a population-based MRI study: The Wakayama Spine Study.
abstract: Tandem spinal stenosis (TSS) is a condition of combined spinal stenosis in the cervical and lumbar regions. The purpose of this study was to determine the prevalence of radiographic TSS and its association with developmental canal stenosis (DCS). The second purpose was to investigate the extent to which radiographic TSS is associated with cervical myelopathy and symptomatic LSS.
  
  
  
  We recruited 1011 (336 men and 675 women) participants in this population-based study. After excluding those with a pacemaker, a history of cervical or lumbar surgery, disqualification, the MRI data of whole spine was analysed in 931 (mean, 67.3 years) participants. Cervical cord compression (CCC) and radiographic lumbar spinal stenosis (LSS) were evaluated by MRI. The canal-to-body ratio was also measured by plain X-ray. DCS was diagnosed as canal-to-body ratio <0.75. The diagnosis of cervical myelopathy and symptomatic LSS was made by presentation of both symptoms and radiographic compression using MRI.
  
  
  
  The prevalence of CCC was 24.7%, that of radiographic LSS was 30.2%, and that of radiographic TSS was 11.0% (men, 14.1%; women, 9.4%). The prevalence of TSS was significantly higher in the DCS group than in the non-DCS group (p < 0.001). Among the participants with radiographic TSS, the prevalence of cervical myelopathy and symptomatic LSS was 9.8 and 18.6%, respectively. The coexisting cervical myelopathy and symptomatic LSS was 6.1% in the participants with LSS.
  
  
  
  The present study is the first population-based study to clarify TSS characteristic using whole-spine MRI.
authors.affiliation: Department of Orthopaedic Surgery, Wakayama Medical University, 811-1 Kimidera, Wakayama, Wakayama, 641-8509, Japan.
authors.forename: Keiji
authors.initials: K
authors.lastname: Nagata
authors.affiliation: Department of Joint Disease Research, Faculty of Medicine, 22nd Century Medical and Research Center, The University of Tokyo, Tokyo, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Yoshimura
authors.affiliation: Department of Orthopaedic Surgery, Wakayama Medical University, 811-1 Kimidera, Wakayama, Wakayama, 641-8509, Japan. hashizum@wakayama-med.ac.jp.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hashizume
authors.affiliation: Department of Orthopaedic Surgery, Wakayama Medical University, 811-1 Kimidera, Wakayama, Wakayama, 641-8509, Japan.
authors.forename: Yuyu
authors.initials: Y
authors.lastname: Ishimoto
authors.affiliation: Department of Joint Disease Research, Faculty of Medicine, 22nd Century Medical and Research Center, The University of Tokyo, Tokyo, Japan.
authors.forename: Shigeyuki
authors.initials: S
authors.lastname: Muraki
authors.affiliation: Department of Orthopaedic Surgery, Wakayama Medical University, 811-1 Kimidera, Wakayama, Wakayama, 641-8509, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamada
authors.affiliation: Department of Medical Research and Management for Musculoskeletal Pain, 22nd Century Medical and Research Center, Faculty of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Oka
authors.affiliation: Japan Community Healthcare Organization Tokyo Shinjuku Medical Center, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kawaguchi
authors.affiliation: Rehabilitation Services Bureau, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Saitama, Japan.
authors.forename: Toru
authors.initials: T
authors.lastname: Akune
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Sakae
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Rehabilitation Services Bureau, National Rehabilitation Center for Persons with Disabilities, Tokorozawa, Saitama, Japan.
authors.forename: Kozo
authors.initials: K
authors.lastname: Nakamura
authors.affiliation: Department of Orthopaedic Surgery, Wakayama Medical University, 811-1 Kimidera, Wakayama, Wakayama, 641-8509, Japan.
authors.forename: Munehito
authors.initials: M
authors.lastname: Yoshida
mesh_terms: D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D015995:Prevalence; D013130:Spinal Stenosis / Q000000981:diagnostic imaging / Q000453:epidemiology; D013131:Spine / Q000000981:diagnostic imaging
keywords: Canal-to-body ratio; Cervical cord compression; Developmental canal stenosis; Lumbar spinal stenosis; Tandem spinal stenosis