High-frequency loading of lumbar ligaments increases proinflammatory cytokines expression in a feline model of repetitive musculoskeletal disorder.

BACKGROUND CONTEXT: Cumulative (repetitive) lumbar disorder is common in the workforce, and the associated epidemiology points out high risk for lifting heavy loads, performing many repetitions, and performing movements at high velocity. Experimental verification of viscoelastic tissue degradation and a neuromuscular disorder exist for cyclic work under heavy loads. Experimental validation for a disorder because of cyclic loads under high-velocity movement is missing. PURPOSE: Obtain experimental verification that high-velocity lumbar flexion-extension results in significant increase of proinflammatory cytokines in the viscoelastic tissues. STUDY DESIGN: Laboratory experiments using two in vivo feline model groups subjected to cyclic flexion-extension at low and high velocity. METHODS: Seven hours after cumulative 60 minutes of cyclic flexion-extension at moderate load of 40 N and 0.25 Hz for first group and 0.5 Hz for the second group, the supraspinous ligaments of L3-L4 to L5-L6 were harvested and subjected to cytokines (interleukin [IL]-1ß, IL-6, IL-8, tumor necrosis factor-α, and transforming growth factor-ß1) analysis. Two-way mixed model analysis of variance with a post hoc analysis were used to assess any significant differences (p<.05) in cytokines expression level between the two groups as well as main effect and interaction with lumbar levels. RESULTS: Expression levels of the five cytokines were significantly increased in the group subjected to the high-frequency loading. CONCLUSIONS: Exposure of the lumbar spine to high-velocity flexion-extension triggers a significant increase in proinflammatory cytokines, indicating pronounced changes consistent with an acute inflammation. Further exposure to activity over prolonged periods may trigger chronic inflammation and tissue degeneration as the source of cumulative lumbar disorder.

Acute morbidity and complications of thigh compartment syndrome: A report of 26 cases.

BACKGROUND: To describe the patient population, etiology, and complications associated with thigh compartment syndrome (TCS). TCS is a rare condition, affecting less than 0.3% of trauma patients, caused by elevated pressure within a constrained fascial space which can result in tissue necrosis, fibrosis, and physical impairment in addition to other complications. Compartment releases performed after irreversible tissue ischemia has developed can lead to severe infection, amputation, and systemic complications including renal insufficiency and death. METHODS: This study examines the course of treatment of 23 consecutive patients with 26 thigh compartment syndromes sustained during an eight-year period at two Level 1 trauma centers, each admitting more than 2,000 trauma patients yearly. RESULTS: Patients developing TCS were young (average 35.4 years) and likely to have a vascular injury on presentation (57.7%). A tense and edematous thigh was the most consistent clinical exam finding leading to compartment release (69.5%). Average time from admission to the operating room was 18 +/- 4.3 hours and 8/23 (34.8%) were noted to have ischemic muscle changes at the time of release. Half of those patients (4/8) developed local complications requiring limb amputations. CONCLUSION: TCS is often associated with high energy trauma and is difficult to diagnose in uncooperative, obtunded and multiply injured patients. Vascular injuries are a common underlying cause and require prompt recognition and a multidisciplinary approach including the trauma and orthopaedic surgeons, intensive care team, vascular surgery and interventional radiology. Prompt recognition and treatment of TCS are paramount to avoid the catastrophic acute and long term morbidities.