spondylolysis and spondylolisthesis LSBU

Description: Radiology case 338-4232 Clinical presentation: 58 year old man with 'sciatica' and back pain.
The theca is opacified with water soluble contrast. There is forward slip of L4 upon L5 with narrowing of the L4/L5 disc and adjacent end-plate sclerosis. The theca is distorted and narrowed at the same level. The AP view shows narrowing of the theca and amputation of the emerging L4 nerve roots. The increased distance between the upper facets of L4, articulating with L3, and the lower facets, articulating with L5, is made possible by a bilateral defect in the articular mass or pars interarticularis of L4.