Lumbar spinal stenosis (LSS) is diagnosed by a history of claudication, clinical investigation, cross-sectional area (CSA) of the dural sac on MRI or CT, and walking distance on the treadmill test. As radiological findings do not always correlate with clinical symptoms, additional diagnostic signs are needed. In patients without LSS, we observe the sedimentation of lumbar nerve roots to the dorsal part of the dural sac on supine MRI scans. In patients with LSS, this sedimentation is rarely seen. We named this phenomenon ‘sedimentation sign’ and defined the absence of sedimenting nerve roots as positive sedimentation sign for the diagnosis of LSS. We hypothesised that the new sedimentation sign discriminates between non-specific low back pain (LBP) and LSS. This prospective case-control study included 200 patients in an orthopaedic in- and outpatient clinic. Patients in the LBP group (n=100) had low back pain, a cross-sectional area (CSA) of the dural sac >120mm2, and a walking distance >1000m; patients in the LSS group (n=100) showed claudication, a CSA < 80mm2, and a walking distance < 200m.Hypothesis
Methods and analysis
Total disc replacement (TDR) provides an alternative to fusion that is designed to preserve motion at the treated level and restore disc height. The effects of TDR on spine biomechanics at the treated and adjacent levels are not fully understood. Thus, the present study investigated facet changes in contact pressure, peak contact pressure, force, peak force, and contact area at the facet joints after TDR. Seven fresh-frozen human cadaveric lumbar spines were potted at T12 and L5 and installed in a 6-DOF displacement-controlled testing system. Displacements of 15° flexion/extension, 10° right/left bending, and 10° right/left axial rotation were applied. Contact pressure, peak contact pressure, force, peak force and contact area for each facet joint were recorded at L2-L3 and L3-L4 before and after TDR at L3-L4 (ProDisc-L, Synthes Spine). The data were analysed with ANOVAs/t-tests.Introduction
Methods
