Dural ectasia and conventional radiography in the Marfan lumbosacral spine

Objective. To determine how well conventional radiographic findings can pre dict the presence of dural ectasia in Marfan patients. Design and patients. Twelve Marfan patients without dural ectasia and 21 Ma rfan patients with dural ectasia were included in the study. Five radiograp hic measurements were made of the lumbosacral spine: interpediculate distan ce, scalloping value, sagittal canal diameter, vertebral body width, and tr ansverse process width. Results. The following measurements were significantly larger in patients w ith dural ectasia: interpediculate distances at L3-L4 levels (P <0.03); sca lloping values at the L1 and L5 levels (P <0.05); sagittal diameters of the vertebral canal at L5-S1 (P <0.03); transverse process to width ratios at L2 (P <0.03). Criteria were developed for diagnosis of dural ectasia in Mar fan patients. These included presence of one of the following: interpedicul ate distance at L4 greater than or equal to 38.0 mm, sagittal diameter at S 1 greater than or equal to 18.0 mm, or scalloping value at L5 greater than or equal to5.5 mm. Conclusion. Dural ectasia in Marfan syndrome is commonly associated with se veral osseous changes that are observable on conventional radiographs of th e lumbosacral spine. Conventional radiography can detect dural ectasia in p atients with Marfan syndrome with a very high specificity (91.7%) but a low sensitivity (57.1%).