Evolution of lumbar degenerative spondylolisthesis with key radiographic features.

Spondylolisthesis is a common finding in middle-aged and older adults with back pain. The pathophysiology of degenerative spondylolisthesis is a subject of controversy regarding not only its etiology but also the mechanisms of its progression. It is theorized that degeneration of the facets and discs can lead to segmental instability, leading to displacement over time. Kirkaldy-Willis divided degenerative spondylolisthesis into three phases: dysfunction, instability, and finally, restabilization. There is a paucity of literature on the unification of the radiological hallmarks seen in spondylolisthesis within these phases. The radiographic features include (1) facet morphology/arthropathy, (2) facet effusion, (3) facet vacuum, (4) synovial cyst, (5) interspinous ligament bursitis, and (6) vacuum disc as markers of dysfunction, instability, and/or restabilization. We discuss these features, which can be seen on X-ray, CT, and MRI, with the intention of establishing a timeline upon which they present clinically. Spondylolisthesis is initiated as either degeneration of the intervertebral disc or facet joints. Early degeneration can be seen as facet vacuum without considerable arthropathy. As the vertebral segment becomes increasingly dynamic, fluid accumulates within the facet joint space. Further degeneration will lead to the advancement of facet arthropathy, degenerative disc disease, and posterior ligamentous complex pathology. Facet effusion can eventually be replaced with a vacuum in severe facet osteoarthritis. Intervertebral disc vacuum continues to accumulate with further cleft formation and degeneration. Ultimately, autofusion of the vertebra at the facets and endplates can be observed. With this review, we hope to increase awareness of these radiographical markers and their timeline, thus placing them within the framework of the currently accepted model of degenerative spondylolisthesis, to help guide future research and to help refine management guidelines.

Determining cut-off scores for simulated tasks in Brazilian Air Force military personnel.

INTRODUCTION: Combat readiness assessments through simulated tasks (STs) have been developed for the Brazilian Air Force (BAF) to establish physical employment standards. Previous research has established BAF critical combat tasks with STs developed based on the physical demands of these tasks. Before implementing these STs, the standards required of BAF personnel must be established. The aim of this study was to determine the cut-off scores for five previously established STs. METHODS: Eighty-eight cadets attended three different testing batteries in order to complete the five STs, being: Battery 1 (foot march), Battery 2 (plane crash on water and water survival skills) and Battery 3 (plane crash on land, obstacle course) with their times recorded. Cut-off scores were set at the 85th percentile of the data distribution with these values and then analysed by four subject matter experts (SMEs) using subjective criteria through criterion analysis. RESULTS: All 88 cadets were submitted to the five assessments. After analysing the performance results on the STs, the SMEs discussed and agreed on the following cut-off scores: obstacle course (3:21 min:s), foot march (31:00 min:s), plane crash on land (1:25 min:s), plane crash on water (1:12 min:s) and water survival skills (4:03 min:s). CONCLUSION: The outcomes of this research allow for the five STs to be implemented in BAF cadets and qualified BAF personnel with the established cut-off scores used to monitor the operational capability of these personnel (be it for cadet training outcomes or unit preparedness assessments) and to guide conditioning practices if personnel are below standards.