Impacto del sacrificio de la arteria radial en la perfusión de la mano / Impact of radial artery sacrifice in hand perfusion

Introducción: El ortopedista se enfrenta a situaciones donde impera el sacrificio de la arteria radial, ya sea en el uso del árbol arterial radial como donante de tejido vascularizado o en situaciones donde la arteria radial es lesionada. El objetivo de este estudio fue determinar los cambios morfológicos y funcionales en la circulación de la mano luego del sacrificio de la arteria radial. Materiales y Métodos: Se realizó un estudio de corte transversal sobre la base de una revisión de historias clínicas de 41 pacientes de ambos sexos, sometidos a cirugía de revascularización miocárdica a quienes se les resecó la arteria radial para ser utilizada como injerto. Los pacientes fueron evaluados mediante ecografía bidimensional y Doppler comparativa de ambos antebrazos, oximetría de pulso del dedo índice de ambas manos en reposo y estrés por ejercicio, y centellografía de ambos miembros superiores en reposo y estrés. Se constataron los síntomas y signos subjetivos de intolerancia al frío y en situación de estrés luego del ejercicio. Los resultados fueron valorados estadísticamente. Resultados: Solo dos pacientes (4,8%) tuvieron síntomas de claudicación de la mano operada durante actividades intensas. La valoración comparativa de ambas manos por oximetría de pulso y de perfusión por centellografía no arrojó diferencias estadísticamente significativas. La diferencia fue estadísticamente significativa en la medición ecográfica del diámetro de ambas arterias cubitales. Conclusión: La perfusión de la mano luego del sacrificio de la arteria radial no se ve comprometida. Nivel de Evidencia: IV

Introduction: Orthopedists face situations in which the radial artery is sacrificed, either for its use as donor of vascularized tissue for coverage of soft tissue defects or in situations where the radial artery is injured. The aim of this study was to determine the morphological and/or functional changes in hand circulation after the radial artery is sacrificed. Methods: A cross-sectional study was conducted based on the review of medical records of 41 patients of both sexes who underwent cardiac revascularization surgery in which a radial artery graft was used. Patients were evaluated using twodimensional and Doppler ultrasound comparing both forearms, index finger pulse oximetry of both hands at rest and after stress, and scintigraphy of both upper limbs at rest and after stress. Statistical evaluation was performed. Results: Only two patients (4.8%) had symptoms of hand claudication during intense activities. Comparative assessment of both hands by pulse oximetry and perfusion scintigraphy yielded no statistically significant difference. There was a statistically significant difference in ultrasound measurement of the diameter of both ulnar arteries. Conclusion: Perfusion of the hand after the sacrifice of the radial artery is not compromised. Level of Evidence: IV

Novel experimental effects on bone material properties and the pre- and postyield behavior of bones may be independent of bone mineralization.

In this article, we summarize the results of six different tomographic/biomechanical rat studies involving hypophysectomy (Hx), ovariectomy, treatment with rhGH, olpadronate, alendronate, and toxic doses of aluminum and the development of a genetic diabetes in the eSS strain. All these conditions induced some interesting and rarely reported effects on postyield bone strength. These effects were generally related neither to the degree of mineralization or the elastic modulus of the bone tissue nor to the preyield behavior of the bones. In two particular cases (Hx, eSS), the elastic modulus of bone tissue varied independently of its degree of mineralization. These results suggest the involvement of some microstructural factor(s) of bone tissue resistance to crack progression (a postyield feature of bone behavior), rather than to crack initiation (the yield-determining factor) in the corresponding mechanism. Changes in collagen or crystal structure may play that role. These changes are relevant to the mechanism of fracture production during plastic deformation, a feature of bone strength that might be independent from mineralization. Therefore, these changes might help to explain some effects of novel treatments on bone strength unrelated to bone mineralization. This questions the belief that the remaining bone mass in metabolic osteopenias is biologically and mechanically normal.

Absorptiometric assessment of muscle-bone relationships in humans: reference, validation, and application studies.

This report summarizes some preliminary absorptiometric (DXA, QCT/pQCT) studies from our laboratory, supporting the following assumptions. 1. In Homo sapiens at all ages, natural proportionality between DXA-assessed bone mineral mass (bone mineral content, BMC) and muscle mass (lean mass, LM) of the whole body or limbs is specific for ethnicity, gender, and reproductive status, but not for body weight, height, or body mass index. 2. This proportionality is sensitive to many kinds of endocrine-metabolic perturbations. 3. Percentilized or Z-scored charts of the BMC/LM correlations as determined in large samples of healthy individuals can provide a diagnostic reference for evaluating proportionality in different conditions. 4. Employing exclusively DXA, this methodology can be applied to discriminate between "disuse-related" and "metabolic" osteopenias based on the finding of normal or low BMC/LM percentiles or Z-scores respectively, with important therapeutic and monitoring implications.