title: Occult neural foraminal stenosis caused by association between disc degeneration and facet joint osteoarthritis: demonstration with dedicated upright MRI system.
abstract: OBJECTIVE
  The aim of our study was to evaluate the presence of dynamic foraminal stenosis using a new low-field dedicated magnetic resonance (MR) unit with a balancing system that allows images to be acquired both in the recumbent and upright position. Imaging of lumbar spine with the patient in a supine, nonweight-bearing position is likely to misrepresent the degree and potential risk of spinal stenosis.
  
  
  METHODS
  In the period between September 2008 and May 2011, we selected 630 symptomatic patients aged 40-65 years (mean age 56) who underwent conventional MR in clinostatic position. The study only included selected patients (total 160) who underwent clinostatic and orthostatic evaluation using a dedicated MR system (G-scan). The biomechanical parameters were also considered. Changes in the dimension of the neural foramina were compared using the presence of disc and facet degeneration by statistical analysis.
  
  
  RESULTS
  Stenosis of the intervertebral foramen was never found in the presence of normal intervertebral discs either in the presence or in the absence of facet disease, in either clinostatic or orthostatic position. Sixty-one stenotic levels were detected which were visualised exclusively in scans obtained under weight-bearing conditions. We named this dynamic condition "occult stenosis". In all of these cases, disc disease was associated with facet pathology.
  
  
  CONCLUSIONS
  Our data show that the association between disc pathology and facet osteoarthrosis can cause occult foraminal stenosis. Strategies to image the spine under physiological load conditions may improve the clinical diagnosis of radicular pain.
authors: Department of Radiology, University of L'Aquila, 67100, L'Aquila, Italy, alessandra.splendiani@cc.univaq.it.
authors: Alessandra
authors: A
authors: Splendiani
authors: Fabiana
authors: F
authors: Ferrari
authors: Antonio
authors: A
authors: Barile
authors: Carlo
authors: C
authors: Masciocchi
authors: Massimo
authors: M
authors: Gallucci
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D055959:Intervertebral Disc Degeneration / Q000150:complications*; D008279:Magnetic Resonance Imaging / Q000295:instrumentation*; D008297:Male; D008875:Middle Aged; D055013:Osteoarthritis, Spine / Q000150:complications*; D010147:Pain Measurement; D013130:Spinal Stenosis / Q000175:diagnosis* / Q000209:etiology*; D021801:Zygapophyseal Joint / Q000473:pathology*