Abstract Introduction Ongoing research in the use of electromagnetic stimulation as coadjuvant in fracture healing has led the authors to begin generating computer models in order to predict cellular growth changes when cells are electromagnetically stimulated. By generating these models, scientists will be able to better understand how electromagnetic fields affect cellular development. The experimental design integrated a cellular culture bioreactor along with an external magnetic stimulation system, which allowed for dermal models to be exposed to controlled magnetic fields. Methods Initially, it was necessary to analyze the static growth of Normal Human Skin Fibroblast (NHSF) cells when they were exposed to Extremely Low Frequency – Electromagnetic Fields (ELF-EMFs). Using optimal conditions for the NHSF culture, from stimulation signal to scaffolding material, we were able to perform the dynamic flow stimulation experiments. Results The following systems were developed: (1) a bioreactor aimed at cellular tissue culture, and (2) Helmholtz coils capable of generating stimulation signals for the cultured tissue. The authors were able to appreciate the quantified values of cellular density diluted in all the experiment samples that were taken and overall, the irradiated samples displayed an average increase of 53% higher cellular density for the same amount of initial cellular seeding when the cells were exposed to a 1 mT, 60 Hz magnetic field signal. Conclusion ELF-EMF’s indeed alter NHSF cell growth rates and it is the challenge of the authors to continue investigating what cellular mechanisms are altered when cells are exposed to ELF-EMF’s.

Introducción: El uso de estimulación electromagnética como coadyuvante en la consolidación de fracturas es controversial en la literatura médica. Métodos: Para este estudio, se diseñó y construyó un dispositivo capaz de generar un campo electromagnético. Tras confirmar su seguridad se asignaron pacientes aleatoriamente con fractura diafisaria de fémur a recibir terapia electromagnética o placebo. La estimulación inició a las seis semanas de la fractura, 1 h diaria, por ocho semanas consecutivas. Se construyeron 20 dispositivos, 10 reales y 10 dispositivos-placebo. Entre junio 2008 y octubre 2009, ingresaron 64 pacientes al estudio de dos instituciones y fueron seguidos durante 24 semanas. El promedio de edad de los pacientes fue de 30 años (rango 18-59) y 81% eran de sexo masculino. Resultados: La consolidación observada para el grupo con el dispositivo y el grupo placebo fue: en la semana 12, 75% vs. 58% (p =0.1); en la semana 18, 94% vs. 80% (p =0.15) y en la semana 24, 94% vs. 87% (p =0.43). Discusión: Este estudio muestra una tendencia a la consolidación más temprana al estar expuesto a un campo electromagnético frente a placebo. Una consolidación más temprana permite un apoyo precoz y, así, más rápida reincorporación al trabajo y a las actividades cotidianas.

Introduction: There is controversy in medical literature regarding the use of electromagnetic fields to promote bone healing. Methods: After designing and building devices capable of generating an electromagnetic field for this study, their safety was confirmed and the electromagnetic therapy was randomly allocated and compared to placebo in patients with fracture of the femoral diaphysis. Treatment began six weeks after the fracture and it was administered once a day, during 1 h, for eight consecutive weeks. Twenty devices were built, 10 of which were placebo-devices. Between June 2008 and October 2009, 64 patients were randomized in two different hospitals and were followed for 24 weeks. The mean age was 30 years (18-59) and 81% were males. Results: Healing observed at week 12 was 75% vs. 58% (p= 0.1); at week 18, it was 94% vs. 80% (p= 0.15); and at week 24, it was 94% vs. 87% (p= 0.43) for the device group and the placebo group, respectively. Discussion: This study suggests that an electromagnetic field stimulus can promote earlier bone healing compared to placebo in femoral diaphyseal fractures. Faster bone healing translates into sooner weight bearing, which - in turn - permits quicker return to normal daily activities.

Este artículo presenta el desarrollo e implementación de una metodología para encontrar los valores de conductividad y permitividad eléctrica de los tejidos cortical y medular, en muestras de fémur de bovino. El tamaño de las muestras fue de diez centímetros, procedentes de animales sanos y jóvenes y con un tiempo de cuatro días después de muerto el animal. El hueso sin partes blandas fue empacado al vacío y conservado a 0°C hasta la realización de las pruebas. Para el mantenimiento y tratamiento de las muestras se desarrollaron protocolos experimentales. Para la medición se construyeron un par de electrodos de contacto de los cuales se encontró su valor de impedancia. El sistema de medición fue acompañado de un circuito RC paralelo para disminuir el efecto de la impedancia de los electrodos. Las mediciones se efectuaron para las frecuencias de 100 Hz y 120 Hz. Las variables medidas fueron impedancia (Z) y ángulo ( θ ), y las calculadas a partir de ecuaciones matemáticas, fueron conductividad (σ ) y permitividad (ε ). Los resultados se encontraron dentro de los rangos reportados en literatura.

This paper presents a development and implementation of a methodology to find the electrical properties (conductivity and permittivity) of cortical and medullar tissue in bovine femur samples. The sample size was ten centimeters; they were obtained of healthy and young animals, and after four days animals were dead. Soft parts were removed from the samples and the samples were vacuum packed at 0°C until the tests were done. Experimental protocols for maintenance and treatment of samples were developed. A couple of contact electrodes were built for the measurements and the electrode's impedance was determined. A parallel RC circuit was connected to the measurement system to decrease the electrode's impedance effect. The measurements were done for 100 Hz and 120 Hz. The measured variables were impedance (Z) and angle (θ ), and the calculated variables were conductivity (σ) and permittivity (ε) by means of mathematical equations. The results were in agreement with literature values.