Table

Changes between the first and second MRI measurements of 65 patients who were scheduled for decompressive surgery in a total of 78 levels due to lumbar spinal stenosis.

Outcome MeasureLevels (N = 78)
Schizas
 No change, n (95% CI)42 (42%–65%)
 Increased, n (95% CI)28 (25%–48%)
  +124
  +22
  +32
 Decreased, n (95% CI)8 (4.5%–19%)
  −17
  −21
Dural sac cross-sectional area
 No change3
 Increased47
  +1–10 mm2 7
  +11–20 mm2 7
  +21–30 mm2 4
 Decreased28
  −1 to 10 mm2 9
  −11 to 20 mm2 14
  −21 to 30 mm2 5
Spondylolisthesis
 No change46
 Increased21
  +1 mm8
  +2 mm9
  +3 mm2
  +4 mm1
  +5 mm0
  +6 mm1a
 Decreased11
  –1 mm9
  –2 mm1
  –3 mm1
Forminal stenosis, left
 No change, n (95% CI)63 (70%–89%)
 Increased, n (95% CI)9 (5%–21%)
  +17
  +22
 Decreased, n (95% CI)6 (3%–16%)
  −15
  −21
Foraminal stenosis, right
 No change, n (95% CI)64 (72%–90%)
 Increased (+1), n (95% CI)7 (4%–18%)
 Decreased (−1), n (95% CI)7 (4%–18%)
Disc degeneration
 No change53
 Increased (+1)12
 Decreased (−1)13
  • Abbreviation: MRI, magnetic resonance imaging.

  • Note: Data presented as n for number of levels unless otherwise specified. All patients presented with 2 preoperative MRIs of the lumbar spine within the year before planned surgery. The MRIs were investigated for disc degeneration (Pfirrmann’s classification), foraminal stenosis (Lee’s classification), spondylolisthesis, and central canal stenosis (Schizas score and dural sac cross-sectional area).

  • a Due to lumbosacral transitional vertebra.