3D Anatomy of the Quail Lumbosacral Spinal Canal-Implications for Putative Mechanosensory Function

Slack-based tunable damping leads to a trade-off between robustness and efficiency in legged locomotion

Animals run robustly in diverse terrain. This locomotion robustness is puzzling because axon conduction velocity is limited to a few tens of meters per second. If reflex loops deliver sensory information with significant delays, one would expect a destabilizing effect on sensorimotor control. Hence, an alternative explanation describes a hierarchical structure of low-level adaptive mechanics and high-level sensorimotor control to help mitigate the effects of transmission delays. Motivated by the concept of an adaptive mechanism triggering an immediate response, we developed a tunable physical damper system. Our mechanism combines a tendon with adjustable slackness connected to a physical damper. The slack damper allows adjustment of damping force, onset timing, effective stroke, and energy dissipation. We characterize the slack damper mechanism mounted to a legged robot controlled in open-loop mode. The robot hops vertically and planarly over varying terrains and perturbations. During forward hopping, slack-based damping improves faster perturbation recovery (up to 170%) at higher energetic cost (27%). The tunable slack mechanism auto-engages the damper during perturbations, leading to a perturbation-trigger damping, improving robustness at a minimum energetic cost. With the results from the slack damper mechanism, we propose a new functional interpretation of animals' redundant muscle tendons as tunable dampers.

Presentation, Diagnosis, and Management of Lower Back Pain Associated with Spinal Stenosis: A Narrative Review

Lower back pain (LBP) is an extremely common symptom experienced by people of all ages and is also one of the most frequent causes of disability worldwide. This article aims to review the presentation, diagnosis, and management of lower back pain associated with spinal stenosis. The paper we prepared was classified as a "literature narrative review." Nonetheless, when searching for manuscripts included in our work and reviewing them critically, we concentrated on the keywords: "lower back pain", "lumbar spine stenosis", "diagnostic", "rehabilitation", "neurosurgery", "spine", and "elderly". The incidence of chronic lower back pain (CLBP) increases linearly starting with the third decade of life until 60 years old, and it more often affects women. The course of non-specific LBP above all depends on factors not connected with the spine, which include psychological, behavioral, and social factors, determined by the way the condition is perceived by the patient the environment. Lumbar spine stenosis (LSS) is an age-related process of degeneration of the intervertebral discs, ligamentum flavum, and facet joints, which results in narrowing of the space around the neurovascular structures of the spine. Diagnosis of spinal pain syndromes includes radiography (RTG), computed tomography (CT), and magnetic resonance imaging (MRI). Based on the results of imaging studies, neurological examination, and the severity of the disease, treatment can consist of analgesics and rehabilitation, or, when conservative methods are insufficient, surgical treatment is indicated.