title: Lumbar interspinous bursitis (Baastrup disease) in a symptomatic population: prevalence on magnetic resonance imaging.
abstract: METHODS
  Cross-sectional retrospective review of 539 patients with lumbar spine magnetic resonance imaging (MRI).
  
  
  OBJECTIVE
  The purpose of this study was to determine the prevalence of lumbar posterior element interspinous bursitis (Baastrup disease) and to measure the association with degenerative disc disease findings, deformities, age, and gender in symptomatic people.
  
  
  BACKGROUND
  Case reports and small case series describing Baastrup disease exist. The prevalence of Baastrup disease on MRI and association with other degenerative-related findings has not been reported.
  
  
  METHODS
  The study group consisted of 539 patients (51% males, 49% females; age range, 7-89 years old) undergoing routine lumbar spine MRI using sagittal T1-weighted, sagittal T2-weighted, and axial T2-weighted pulse sequences. Retrospective consensus review by 2 observers evaluated for the presence of: fluid intervening between consecutive spinous processes (criterion for Baastrup disease), disc degeneration (spondylosis) and contour abnormalities (bulges, herniations), marrow endplate signal alteration (Modic changes), central canal stenosis, lordosis, scoliosis, and displacement (anterolisthesis, retrolisthesis). Statistical analyses were descriptive statistics and determining associations between these MRI findings and Baastrup disease (using chi and Wilcoxon rank sums).
  
  
  RESULTS
  Lumbar interspinous bursitis (Baastrup disease) was present in 8.2% (44 of 539) of the study population. There were associations between the presence of Baastrup disease and age (P = 0.001), central canal stenosis (P = 0.0013), disc bulging (P = 0.0341), and anterolisthesis (P = 0.0429). There were not associations between Baastrup disease and disc degeneration, disc herniation, endplate findings, retrolisthesis, scoliosis, lordosis, or gender.
  
  
  CONCLUSIONS
  Lumbar interspinous bursitis (Baastrup disease) is uncommon but not infrequent in symptomatic patients undergoing lumbar spine MRI. Patients with MRI evident Baastrup disease tend to be older, have central canal stenosis, bulging discs, and anterolisthesis. Further investigations determining the clinical significance of this finding are necessary.
authors: Gemini-Hospital, Huisduinerweg, Den Helder, Netherlands.
authors: Robbert
authors: R
authors: Maes
authors: Willam B
authors: WB
authors: Morrison
authors: Laurence
authors: L
authors: Parker
authors: Mark E
authors: ME
authors: Schweitzer
authors: John A
authors: JA
authors: Carrino
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002062:Bursitis / Q000175:diagnosis* / Q000453:epidemiology; D016009:Chi-Square Distribution; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008159:Lumbar Vertebrae; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012189:Retrospective Studies; D013122:Spinal Diseases / Q000175:diagnosis* / Q000453:epidemiology; D018709:Statistics, Nonparametric