The aim of this work was to study the influence of the slice orientation of T2 axial images in numerical measurements of DSCA and study the effect that this change of slice angle would have on the morphological grading assessment. TSE T2 three dimensional aquisition MRI studies reconstructed with OsiriX DICOM viewer from 32 patients were used. Patients included were a series of consecutive cases with either suspected spinal stenosis or low back pain. A total of 97 disc levels were studied and axial reconstructions were made at 0°, +10°, +20°, +30° relative to the disc space orientation. For each image, DSCA was digitally measured and a severity grade was assigned by two observers according to the recently-published 4-point (A-D) morphological grading system. Interobserver kappa score was 0.71. Statistical analysis of DSCA measurements was performed using kappa and t-tests. Comparing DCSA between 0° at each level and +10°, +20° and +30° slice orientation, a significant increase in surface area was found in each case (P<0.0001). % change in DSCA combining all disc levels comparing 0° and +10°: range -15.48% to +31.89% (SD 18.40%); 0° and +20°: range -24.00% to +143.82% (SD 20.45%); 0° and +30°: range -29.35% to +231.13% (SD 26.52%). At 13 disc levels, DSCA was <100mm2 at 0°, but changed to >100mm2 in three cases by a +10° increase, in five cases by a +20° increase and in 10 cases by a +30° increase. In only two out of 97 levels studied did the morphological grading change as the angle increased, one of which was not amongst those above (change in DSCA from <100mm2 to >100mm2).Purpose of the study
Methods and Results
We carried out a retrospective review of 155 patients with lumbar spinal stenosis who had been treated surgically and followed up regularly: 77 were evaluated at a mean of 6.5 years (5 to 8) after surgery by two independent observers. The outcome was assessed using the scoring system of Roland and Morris, and the rating system of Prolo, Oklund and Butcher. Instability was determined according to the criteria described by White and Panjabi. A significant decrease in low back pain and disability was seen. An excellent or good outcome was noted in 79% of patients; 9% showed secondary radiological instability. Surgical decompression is a safe and efficient procedure. In the absence of preoperative radiological evidence of instability, fusion is not required.
