Etiology of lumbar lordosis and its pathophysiology: a review of the evolution of lumbar lordosis, and the mechanics and biology of lumbar degeneration

Abstract

<jats:p>The goal of this review is to discuss the mechanisms of postural degeneration, particularly the loss of lumbar lordosis commonly observed in the elderly in the context of evolution, mechanical, and biological studies of the human spine and to synthesize recent research findings to clinical management of postural malalignment. Lumbar lordosis is unique to the human spine and is necessary to facilitate our upright posture. However, decreased lumbar lordosis and increased thoracic kyphosis are hallmarks of an aging human spinal column. The unique upright posture and lordotic lumbar curvature of the human spine suggest that an understanding of the evolution of the human spinal column, and the unique anatomical features that support lumbar lordosis may provide insight into spine health and degeneration. Considering evolution of the skeleton in isolation from other scientific studies provides a limited picture for clinicians. The evolution and development of human lumbar lordosis highlight the interdependence of pelvic structure and lumbar lordosis. Studies of fossils of human lineage demonstrate a convergence on the degree of lumbar lordosis and the number of lumbar vertebrae in modern <jats:italic>Homo sapiens</jats:italic>. Evolution and spine mechanics research show that lumbar lordosis is dictated by pelvic incidence, spinal musculature, vertebral wedging, and disc health. The evolution, mechanics, and biology research all point to the importance of spinal posture and flexibility in supporting optimal health. However, surgical management of postural deformity has focused on restoring posture at the expense of flexibility. It is possible that the need for complex and costly spinal fixation can be eliminated by developing tools for early identification of patients at risk for postural deformities through patient history (genetics, mechanics, and environmental exposure) and tracking postural changes over time.</jats:p>

Lumbar spine endplate fractures: Biomechanical evaluation and clinical considerations through experimental induction of injury

“…The natural curvature of the spine in the sagittal plane allows for upright posture with minimal muscle activity and soft tissue deformity. A decrease in lumbar lordosis usually occurs with aging, leading to deviations in SB that can result in stress‐related changes to other segments . Moreover, the gradual and progressive loss of lumbar lordosis aligns the endplates in a more parallel orientation, placing them at a higher risk for endplate failure according to our data.…”

Reliability assessment of a novel cervical spine deformity classification system

“…3,29,35,41,43,51 Although it had been long recognized that normative LL spans a substantial range, perhaps as broad as 30°-90°, it was not clear what determined a normal value for an individual. Recent reports have suggested that the morphology of the pelvis, as measured by the pelvic incidence (PI), is a key determinant of ideal LL.…”

Morphological and postural sexual dimorphism of the lumbar spine facilitates greater lordosis in females

“…), as it contributes to both the load‐bearing capacity and flexibility of the lumbar spine, which are important for activities of daily living (Sparrey et al. ). The lordotic curvature of the lumbar spine resembles a buckled (Euler) column in response to load‐bearing (Meakin et al.…”