Purpose: To develop a list of radiologic criteria for describing lumbar spinal stenosis, to learn from experts which parameters they consider to be most important, and to assess the strength of agreement among experts on the most relevant criteria.
Materials and methods: An expert panel of 41 radiologists (musculoskeletal experts and neuroradiologists from Europe and the United States) was formed. A three-round Delphi survey was conducted. Twenty-seven of the 41 nominated experts agreed to participate; 21 completed all three rounds. In the first round, experts were asked to complete a list of suggested parameters and cutoff values to describe lumbar spinal stenosis. In the second round, panelists rated the diagnostic relevance of each parameter (visual analog scale, 0-10). In the third round, panelists were provided with the group results (median and range) and their own answers and had the opportunity to adapt their judgments from round 2. To assess the degree of consensus among experts, the Cronbach α was calculated.
Results: The qualitative criteria disk protrusion and perineural intraforaminal fat were rated as the most important diagnostic indicators, with median scores of 9 (range, 2-10). The highest rated quantitative criterion was the anteroposterior diameter of the osseous canal, with a median score of 8; however, there was a wide range of scores (range, 0-10). The median Cronbach α of all panelists within the group was 0.81 after the third round.
Conclusion: Results of the survey suggest that there are no broadly accepted quantitative criteria and only partially accepted qualitative criteria for the diagnosis of lumbar spinal stenosis. The latter include disk protrusion, lack of perineural intraforaminal fat, hypertrophic facet joint degeneration, absent fluid around the cauda equine, and hypertrophy of the ligamentum flavum.
© RSNA, 2012.