title: Prevalence and Clinical Relevance of Schmorl's Nodes on Magnetic Resonance Imaging in a Tertiary Hospital in Southern India.
abstract: BACKGROUND
  Schmorl's Nodes (SN), which appear as defects in superior and inferior endplates of vertebrae, are commonly seen around the thoracolumbar junction. They may be asymptomatic or symptomatic. Their prevalence varies with respect to age, gender, regions involved and other associated disc or vertebral findings.
  
  
  OBJECTIVE
  SN is quite a common finding on the Magnetic Resonance Imaging (MRI) of the spine. The purpose of the study was to evaluate the prevalence of SN in the patients who underwent MRI whole spine in the radiology department, ascertain its clinical relevance and to compare the prevalence of SN in the study population with the prevalence in rest of the Indian and global population described already in the literature.
  
  
  METHODS
  Clinical history and MRI images of the patients who underwent whole spine MRI study in the Radiology Department during the period of 6 months from June to December 2015 were retrospectively reviewed. The prevalence of SN, their location and associated imaging findings were studied.
  
  
  RESULTS
  Of the 509 patients in the study, 47 had SN at one or more levels with prevalence of 9.2%. Maximum cases were seen in the 4(th) decade with least cases in the extremes of age. Twenty five patients had SN at thoracic levels. Twenty five patients had SN at lumbar levels. Twenty eight patients had SN at one intervertebral disc level. Other 19 patients had SN at multiple levels. Of the total 103 SN found, 57 were seen in the superior endplates and 46 in the inferior endplates. All SNs were in central position, except for one. Twelve of the 47 patients had disc degeneration at the same level as SN. Forty two of the 47 patients (89%) with Schmorl's nodes had associated spinal disc degenerative disease at the same or different levels. Modic type II endplate changes were demonstrated at the same level in 10 of the 47 patients with SN. Thirty eight of the 47 patients presented with history of backache. Only 9 of these patients had come with history of trauma; of these only four had wedge compression fracture at the level of SN.
  
  
  CONCLUSIONS
  Schmorl's nodes in the studied South Indian population appear to show one of the lowest prevalence described on MRI, so far. Maximum number of SN occurred in the lower thoracic spine followed by the proximal lumbar spine. Schmorl's nodes are commonly associated with degenerative disc disease of the spine, though not at the same level.
authors.affiliation: Professor and Head, Department of Radiodiagnosis, Government Kilpauk Medical College , Chennai, Tamilnadu, India .
authors.forename: Devimeenal
authors.initials: D
authors.lastname: Jagannathan
authors.affiliation: Professor, Department of Radiodiagnosis, Sree Balaji Medical College and Hospital , Chennai, India .
authors.forename: Venkatraman
authors.initials: V
authors.lastname: Indiran
authors.affiliation: Post Graduate MD Student, Department of Radiodiagnosis, Government Kilpauk Medical College , Chennai, Tamilnadu, India .
authors.forename: Fouzal
authors.initials: F
authors.lastname: Hithaya
keywords: Backache; Herniation; India; Intervertebral disc; MRI