title: Describing the size of lumbar disc herniations using computed tomography. A comparison of different size index calculations and their relation to sciatica.
abstract: METHODS
  The study compared different methods to measure the absolute and relative size of lumbar disc herniations on computed tomography scans and their relation to sciatica.
  
  
  METHODS
  Computed tomography (CT) examinations were done before and at 3 and 24 months after nonoperative treatment in 30 patients with lumbar disc herniations. The size of the herniation was described by different indexes and related to the degree of sciatica. One index was formed by the area of the herniation in relation to the spinal canal (A-index), whereas two indexes were formed by linear measurements of the herniation in relation to the spinal canal in either two (ST-index) or one direction (S-index).
  
  
  RESULTS
  Each index was correlated significantly to the degree of sciatica. The area of the herniations decreased markedly over time.
  
  
  CONCLUSIONS
  Linear measurements of the herniation in two perpendicular directions provide a practical and accurate way of describing the size of lumbar disc herniations.
authors.affiliation: Department of Orthopedics, University Hospital, Umeå, Sweden.
authors.forename: U
authors.initials: U
authors.lastname: Thelander
authors.forename: M
authors.initials: M
authors.lastname: Fagerlund
authors.forename: S
authors.initials: S
authors.lastname: Friberg
authors.forename: S
authors.initials: S
authors.lastname: Larsson
mesh_terms: D000328:Adult; D005069:Evaluation Studies as Topic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007403:Intervertebral Disc / Q000000981:diagnostic imaging*; D007405:Intervertebral Disc Displacement / Q000150:complications / Q000000981:diagnostic imaging* / Q000628:therapy; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging*; D008297:Male; D012585:Sciatica / Q000209:etiology*; D013997:Time Factors; D014057:Tomography, X-Ray Computed