Postoperative Hypermobile Instability The recumbent scan for this patient with recurrent low back pain and polyradiculopathy following L4-S1 laminectomy and fusion is shown on the left. The upright scan (right) shows postoperative intersegmental hypermobile instability associated with mobile fluctuating stenosis of the central spinal canal at the level above spinal fusion.
Evaluation of Spinal Stability The recumbent scan (left) demonstrates minor degenerative anterolisthesis at L4/5. The upright-flexion study (right) reveals further anterior slip of L4 on L5. These scans show hypermobile translational spinal instability, which can be a surgical indication in a case of related low back pain.
Position-Related Recurrent Disc Herniation The recumbent scan for this patient with right-sided radiculopathy following partial discectomy is shown on the left. The upright scan (right) shows a disc herniation at L5/S1.