RESUMO

INTRODUCTION: There are different pathologies of the lumbar spine that condition a biomechanical and clinical instability for its treatment, various stabilization techniques have been carried out that try to preserve the movement and the transmission of load of the affected segment such as the interspinatus ligamentplasty with Dallos® fiber. OBJECTIVE: To show the biomechanical variations of functional segment of lumbar spine of pigs, before and after performing the discectomy and ligamentoplasty with Dallos® fiber. MATERIAL AND METHODS: The lumbar segment was mounted in a servo-hydraulic multiaxial simulator. Mobility ranges of flexion, extension, lateral flexion and axial rotations were simulated under three conditions: 1. Natural segment, 2. Discectomy segment, and 3. Disectomized segment plus ligamentoplasty with Dallos® fiber. The mobility ranges are made up to a torque of 7.5 N-m The data of the torques and mobility ranges was collected in the simulator program and the results of the biomechanical changes between the three conditions described were plotted. RESULTS: It was shown that lumbar biomechanics is affected after discectomy mainly in flexion and extension. In the left axial bending and rotation movements, an alteration of torque and mobility ranges was found. CONCLUSIONS: The ligamentoplasty recovers part of the stability lost after discectomy preserving part of the disc height without reaching to equalize the movements as in the natural segment. After discectomy the distribution of force suggests that residual instability with ligament plasty may represent facet overload.

INTRODUCCIÓN: Existen diferentes patologías de la columna lumbar que condicionan una inestabilidad biomecánica y clínica para su tratamiento, se han efectuado diversas técnicas de estabilización que tratan de preservar el movimiento y la transmisión de carga del segmento afecto como la ligamentoplastía interespinosa con fibra Dallos®. OBJETIVO: Mostrar las variaciones biomecánicas de segmento funcional de columna lumbar de porcino, antes y después de realizar la discetomía y ligamentoplastía con fibra Dallos®. MATERIAL Y MÉTODOS: El segmento lumbar se montó en un simulador multiaxial servo-hidráulico. Se simularon rangos de movilidad de flexión, extensión, flexiones laterales y rotaciones axiales en tres condiciones: 1) segmento natural; 2) segmento discectomizado; y 3) segmento disectomizado más ligamentoplastía con fibra Dallos®. Los rangos de movilidad se realizan hasta un torque de 7.5 N-m. La data de los torques y rangos de movilidad se recolectó en el programa del simulador y se graficaron los resultados de los cambios biomecánicos entre las tres condiciones descritas. RESULTADOS: Se demostró que la biomecánica lumbar es afectada después de la discectomía principalmente en la flexión y la extensión. En los movimientos de flexión y rotación axial izquierdas, se comprobó una alteración del torque y los rangos de movilidad. CONCLUSIONES: La ligamentoplastía recupera parte de la estabilidad perdida postdiscectomía, preservando parte de la altura discal sin llegar a igualar los movimientos como en el segmento natural. Posterior a la discectomía, la distribución de la fuerza sugiere que la inestabilidad residual con ligamento plastía puede representar sobrecarga facetaria.

Assuntos

RESUMO

Resumen: Introducción: Existen diferentes patologías de la columna lumbar que condicionan una inestabilidad biomecánica y clínica para su tratamiento, se han efectuado diversas técnicas de estabilización que tratan de preservar el movimiento y la transmisión de carga del segmento afecto como la ligamentoplastía interespinosa con fibra Dallos®. Objetivo: Mostrar las variaciones biomecánicas de segmento funcional de columna lumbar de porcino, antes y después de realizar la discetomía y ligamentoplastía con fibra Dallos®. Material y métodos: El segmento lumbar se montó en un simulador multiaxial servo-hidráulico. Se simularon rangos de movilidad de flexión, extensión, flexiones laterales y rotaciones axiales en tres condiciones: 1) segmento natural; 2) segmento discectomizado; y 3) segmento disectomizado más ligamentoplastía con fibra Dallos®. Los rangos de movilidad se realizan hasta un torque de 7.5 N-m. La data de los torques y rangos de movilidad se recolectó en el programa del simulador y se graficaron los resultados de los cambios biomecánicos entre las tres condiciones descritas. Resultados: Se demostró que la biomecánica lumbar es afectada después de la discectomía principalmente en la flexión y la extensión. En los movimientos de flexión y rotación axial izquierdas, se comprobó una alteración del torque y los rangos de movilidad. Conclusiones: La ligamentoplastía recupera parte de la estabilidad perdida postdiscectomía, preservando parte de la altura discal sin llegar a igualar los movimientos como en el segmento natural. Posterior a la discectomía, la distribución de la fuerza sugiere que la inestabilidad residual con ligamento plastía puede representar sobrecarga facetaria.

Abstract: Introduction: There are different pathologies of the lumbar spine that condition a biomechanical and clinical instability for its treatment, various stabilization techniques have been carried out that try to preserve the movement and the transmission of load of the affected segment such as the interspinatus ligamentplasty with Dallos® fiber. Objective: To show the biomechanical variations of functional segment of lumbar spine of pigs, before and after performing the discectomy and ligamentoplasty with Dallos® fiber. Material and methods: The lumbar segment was mounted in a servo-hydraulic multiaxial simulator. Mobility ranges of flexion, extension, lateral flexion and axial rotations were simulated under three conditions: 1. Natural segment, 2. Discectomy segment, and 3. Disectomized segment plus ligamentoplasty with Dallos® fiber. The mobility ranges are made up to a torque of 7.5 N-m The data of the torques and mobility ranges was collected in the simulator program and the results of the biomechanical changes between the three conditions described were plotted. Results: It was shown that lumbar biomechanics is affected after discectomy mainly in flexion and extension. In the left axial bending and rotation movements, an alteration of torque and mobility ranges was found. Conclusions: The ligamentoplasty recovers part of the stability lost after discectomy preserving part of the disc height without reaching to equalize the movements as in the natural segment. After discectomy the distribution of force suggests that residual instability with ligament plasty may represent facet overload.

RESUMO

The incidence of dengue infections has been increasing in the Caribbean, and cases have been identified among successive deployments of multinational peacekeepers to Haiti (1994-1997). In the absence of an effective vaccine or chemoprophylaxis to prevent dengue fever, vector-control operations and use of personal protection measures to prevent arthropod bites are the most effective means of limiting disease transmission. During our 5-month deployment as part of the United Nations Mission in Haiti, 79 cases of recent dengue fever were identified among 249 patients (32%) presenting with febrile illness to the 86th Combat Support Hospital. Further investigation revealed low unit readiness to perform standard vector-control activities and poor individual adherence to measures to prevent arthropod bites. Command enforcement of existing field preventive medicine doctrine is essential to prevent casualties caused by dengue, other arthropod-borne infections, and nuisance arthropod bites during military deployments.

Assuntos

RESUMO

BACKGROUND: Multinational peacekeepers, both military and civilian, often deploy to areas of the world where significant health threats are endemic and host country public health systems are inadequate. Medical surveillance of deployed personnel enables leaders to better direct health care resources to prevent and treat casualties. Over a 5-month period, June to October 1995, a medical surveillance system (MSS) was implemented in support of the United Nations Mission in Haiti (UNMIH). Information obtained from this system as well as lessons learned from its implementation and management may help decrease casualty rates during future multinational missions. METHODS: Over 90% of UNMIH personnel (80% military from over 11 countries and 20% civilian from over 70 countries) stationed throughout Haiti participated in the MSS. A weekly standardized reporting form included the number of new outpatient visits by disease and non-battle injury (DNBI) category and number of personnel supported by each participating UN medical treatment facility (MTF). Previously, medical reporting consisted of simple counts of patient visits without distinguishing between new and follow-up visits. Weekly incidence rates were determined and trends compared within and among reporting sites. The diagnoses and numbers of inpatient cases per week were only monitored at the 86th Combat Support Hospital, the facility with the most sophisticated level of health care available to UN personnel. RESULTS: The overall outpatient DNBI incidence rate ranged from 9.2% to 13% of supported UN personnel/week. Of the 14 outpatient diagnostic categories, the three categories consistently with the highest rates included orthopaedic/injury (1.6-2.5%), dermatology (1.3-2.2%), and respiratory (0.9-2.2%) of supported UN personnel/week. The most common inpatient discharge diagnoses included suspected dengue fever (22.3%), gastro-enteritis (15%), and other febrile illness (13.5%). Of the 249 patients who presented with a febrile illness, 79 (32%) had serological evidence of recent dengue infection. Surveillance results helped lead to interventions that addressed issues related to field sanitation, potable water, food preparation and vector control. CONCLUSIONS: Despite hurdles associated with distance, language, and communications, the MSS was a practical and effective tool for UNMIH force protection. UN requirements for standardized medical surveillance during deployments should be developed and implemented. Furthermore, planners should recognize that if ongoing medical surveillance and related responses are to be effective, personnel should be trained prior to deployment and resources dedicated to a sustained effort in theatre.

Assuntos