Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Background: Animal spinal cord injury (SCI) models have proved invaluable in better understanding the mechanisms involved in traumatic SCI and evaluating the effectiveness of experimental therapeutic interventions. Over the past 25 years, substantial gains have been made in developing consistent, reproducible and reliable animal SCI models. Study design: Review. Objective: The objective of this review was to consolidate current knowledge on SCI models and introduce newer paradigms that are currently being developed. Results: SCI models are categorized based on the mechanism of injury into contusion, compression, distraction, dislocation, transection or chemical models. Contusion devices inflict a transient, acute injury to the spinal cord using a weight-drop technique, electromagnetic impactor or air pressure. Compression devices compress the cord at specific force and duration to cause SCI. Distraction SCI devices inflict graded injury by controlled stretching of the cord. Mechanical displacement of the vertebrae is utilized to produce dislocation-type SCI. Surgical transection of the cord, partial or complete, is particularly useful in regenerative medicine. Finally, chemically induced SCI replicates select components of the secondary injury cascade. Although rodents remain the most commonly used species and are best suited for preliminary SCI studies, large animal and nonhuman primate experiments better approximate human SCI. Conclusion: All SCI models aim to replicate SCI in humans as closely as possible. Given the recent improvements in commonly used models and development of newer paradigms, much progress is anticipated in the coming years. Spinal Cord (2014) 52, 588-595; doi:10.1038/sc.2014.91; published online 10 June 2014 INTRODUCTIONSpinal cord injury (SCI) models have proved indispensible not only for investigating the efficacy of therapeutic interventions but also for better understanding the molecular pathways involved. SCI models have evolved significantly over the past century since Allen developed the first weight-drop contusion model in 1911. 1 SCI models aim to recreate features of human SCI as closely as possible. These models vary in terms of the animal utilized, site of injury infliction and injury mechanism.Rats are used most commonly in preliminary studies as they are relatively inexpensive, readily available and have demonstrated similar functional, electrophysiological, and morphological outcomes to humans following SCI. 2 Mice are particularly useful for genetic studies. 3 Nonhuman primate SCI models-including marmosets, macaques and squirrel monkeys-better approximate human SCI than rodent models, and they accommodate assessment of multiple recovery variables and rehabilitative therapy. 4 New world primates like marmosets confer advantages over old world primates as they are smaller, easier to handle, have a higher breeding efficiency and can be bred in experimental colonies. SCI models that incorporate large animals-such as pigs or dogs-can also be used when it is important for furth...

This study is the first to correlate cervical sagittal balance (C2-C7 SVA) to myelopathy severity. We found a moderate negative correlation in kyphotic patients of cord volume and cross-sectional area to mJOA scores. The opposite (positive correlation) was found for lordotic patients, suggesting a relationship of cord volume to myelopathy that differs on the basis of sagittal alignment. It is interesting to note that sagittal balance but not kyphosis is tied to myelopathy score. Future work will correlate alignment changes to cord morphology changes and myelopathy outcomes. SUMMARY STATEMENTS: This is the first study to correlate sagittal balance (C2-C7 SVA) to myelopathy severity. We found a moderate negative correlation in kyphotic patients of cord volume and cross-sectional area to mJOA scores. The opposite (positive correlation) was found for lordotic patients, suggesting a relationship of cord volume to myelopathy that differs on the basis of sagittal alignment.

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Achilles tendon pathology is common and affects athletes and nonathletes alike. The cause is multifactorial and controversial, involving biological, anatomical, and mechanical factors. A variety of conditions characterized by Achilles tendon inflammation and/or degeneration can be clinically and histologically differentiated. These include insertional Achilles tendinopathy, retrocalcaneal bursitis, Achilles paratenonitis, Achilles tendinosis, and Achilles paratenonitis with tendinosis. The mainstay of treatment for all of these diagnoses is nonoperative. There is a large body of evidence addressing treatment of acute and chronic Achilles tendon ruptures; however, controversy remains.