Interface-inspired formulation and molecular-level perspectives on heat conduction and energy storage of nanofluids.

Aiming for the introduction of stability requirements in nanofluids processing, an interface-based three-step method is proposed in this work. It is theory-based design framework for nanofluids that aims for a minimum tension at the solid-liquid interface by adjusting the polar and dispersive components of the base fluid to meet those of disperse nanomaterial. The method was successfully tested in the preparation of aqueous nanofluids containing single-walled carbon nanotubes that resulted to be stable and to provide good thermal properties, i.e. thermal conductivity increases by 79.5% and isobaric specific heat by 8.6% for a 0.087 vol.% load of nanotubes at 70 °C. Besides, a system for these nanofluids was modelled. It was found to be thermodynamically consistent and computationally efficient, providing consistent response to changes in the state variable temperature in a classical Molecular Dynamics environment. From an analysis of the spatial components of the heat flux autocorrelation function, using the equilibrium approach, it was possible to elucidate that heat conduction through the host fluid is enhanced by phonon propagation along nanotubes longitudinal axes. From an analysis of the structural features described by radial distribution functions, it was concluded that additional heat storage arises from the hydrophobic effect.

Escoliosis idiopáticas graves. ¿El abordaje y la instrumentación modifican los resultados? / Severe idiopathic scoliosis. Does the approach and the instruments used modify the results?

Objetivo: El objetivo de este trabajo es evaluar y comparar los resultados radiográficos y las complicaciones del tratamiento quirúrgico de escoliosis idiopáticas del adolescente mayores de 75◦ mediante doble abordaje (DA) o vía posterior aislada con instrumentación híbrida (PH) o «todo-tornillos» (PT). Material y método: Se realiza una revisión retrospectiva de 69 pacientes con escoliosis idiopática del adolescente mayor de 75◦ y seguimiento superior a los 2 años para analizar la flexibilidad de las curvas, la corrección obtenida y las complicaciones en función del tipo de cirugía. El análisis estadístico se realizó mediante el test de Kruskal-Wallis para variables no paramétricas. Resultados: No existen diferencias estadísticamente significativas entre los 3 grupos en los valores del ángulo de Cobb preoperatorio (DA = 89◦, PH = 83◦, PT = 83◦), en el postoperatorio inmediato (DA = 34◦, PH = 33◦, PT = 30◦) ni al final del seguimiento (DA = 36◦, PH = 36◦, PT = 33◦) (p > 0,05). El porcentaje de corrección (DA = 60%, PH = 57%, PT = 60%) fue similar entre grupos (p > 0,05). El porcentaje de complicaciones relacionadas con el procedimiento fue del 20,8% en DA, del 10% en PH y del 20% en PT. Dos pacientes en el grupo PT experimentaron cambios en la monitorización medular sin lesión neurológica y un paciente del mismo grupo experimentó una lesión incompleta diferida y temporal. Discusión y conclusiones: No se aprecian diferencias significativas en la corrección de las escoliosis idiopáticas graves entre los pacientes intervenidos mediante doble abordaje o por vía posterior aislada, independientemente del tipo de instrumentación utilizada (AU)

Objective: The aim of this work is to evaluate and compare the radiographic results and complications of the surgical treatment of adolescents with idiopathic scoliosis greater than 75 degrees, using a double approach (DA) or an isolated posterior approach with hybrid instruments (posterior hybrid [PH]), or with «all-pedicle screws» (posterior screws [PS]). Material and method: A retrospective review was performed on 69 patients with idiopathic scoliosis greater than 75◦, with a follow-up of more than 2 years, to analyze the flexibility of the curves, the correction obtained, and the complications depending on the type of surgery. The Kruskal-Wallis test for non-parametric variables was used for the statistical analysis. Results: There were no statistically significant differences between the 3 patient groups in the pre-surgical Cobb angle values (DA = 89◦, PH = 83◦, PS = 83◦), in the immediate post-surgical (DA = 34◦, PH = 33◦, PS = 30◦), nor at the end of follow-up (DA = 36◦, PH = 36◦, PS = 33◦) (P > .05). The percentage correction (DA = 60%, PH = 57%, PS = 60%) was similar between groups (P > .05). The percentage of complications associated with the procedure was 20.8% in DA, 10% in PH and 20% in PS. Two patients in the PS group showed changes, with no neurological lesions, in the spinal cord monitoring, and one patient in the same group suffered a delayed and transient incomplete lesion. Discussion and conclusions: No significant differences were observed in the correction of severe idiopathic scoliosis between patients operated using the double or isolated posterior approach, regardless of the type of instrumentation used (AU)

[Severe idiopathic scoliosis. Does the approach and the instruments used modify the results?]. / Escoliosis idiopáticas graves. ¿El abordaje y la instrumentación modifican los resultados?

OBJECTIVE: The aim of this work is to evaluate and compare the radiographic results and complications of the surgical treatment of adolescents with idiopathic scoliosis greater than 75 degrees, using a double approach (DA) or an isolated posterior approach with hybrid instruments (posterior hybrid [PH]), or with «all-pedicle screws¼ (posterior screws [PS]). MATERIAL AND METHOD: A retrospective review was performed on 69 patients with idiopathic scoliosis greater than 75°, with a follow-up of more than 2 years, to analyze the flexibility of the curves, the correction obtained, and the complications depending on the type of surgery. The Kruskal-Wallis test for non-parametric variables was used for the statistical analysis. RESULTS: There were no statistically significant differences between the 3 patient groups in the pre-surgical Cobb angle values (DA=89°, PH=83°, PS=83°), in the immediate post-surgical (DA=34°, PH=33°, PS=30°), nor at the end of follow-up (DA=36°, PH=36°, PS=33°) (P>.05). The percentage correction (DA=60%, PH=57%, PS=60%) was similar between groups (P>.05). The percentage of complications associated with the procedure was 20.8% in DA, 10% in PH and 20% in PS. Two patients in the PS group showed changes, with no neurological lesions, in the spinal cord monitoring, and one patient in the same group suffered a delayed and transient incomplete lesion. DISCUSSION AND CONCLUSIONS: No significant differences were observed in the correction of severe idiopathic scoliosis between patients operated using the double or isolated posterior approach, regardless of the type of instrumentation used.

Modulación del crecimiento de columnas escolióticas en animales de experimentación mediante el uso de barras de metal inteligente / Modulation of scoliotic spine growth in experimental animals using intelligent metal bars

Objetivo. Creación de un modelo experimental de escoliosis estructurada en ratas para evaluar la eficacia de los metales con memoria de forma para corregir gradualmente la deformidad a lo largo del tiempo. Material y método. Se generó una escoliosis experimental en ratas de 3 semanas mediante una sutura entre escápula y pelvis izquierdas durante 8 semanas, tras lo cual fueron aleatorizadas en 2 grupos: control, en los que se cortó la sutura, y nitinol, en los que además se implantó un alambre recto con memoria de forma anclado a la columna. Se realizaron radiografías seriadas para determinar la eficacia del nitinol en la corrección de la escoliosis. En un segundo tiempo, evaluamos los cambios histológicos a nivel del cuerpo vertebral apical y discos adyacentes pre y poscorrección. Resultados. Se indujo una cifoescoliosis progresiva media de 81,5°. En el grupo control, tras cortar la sutura, se produjo una reducción inicial de la deformidad pero luego permaneció estable a lo largo del tiempo (54° a las 2 semanas). En el grupo nitinol se observó una reducción progresiva del valor angular de la escoliosis, hasta 8,7° de media a las 2 semanas. El acuñamiento del cuerpo vertebral apical y de los discos adyacentes se corregía parcialmente tras 2 semanas de corrección de la deformidad. Conclusión. En este modelo de escoliosis, un alambre recto de nitinol anclado a la columna ha demostrado eficacia para la corrección gradual de la cifoescoliosis, y de los cambios estructurales asociados a la misma (AU)

Objective: To create an experimental structural scoliosis model in mice to evaluate the efficacy of shape-memory metals to gradually correct the deformity over time. Material and method: Experimental scoliosis was generated in 3 week-old mice by means of a suture between the left scapula and pelvis for 8 weeks. They were then randomised into two groups: a control group, in which the suture was cut, and another, in those that also had a Nitinol straight memory-wire implant fixed to the column. Serial X-rays were performed to determine the efficacy of the Nitinol in the correction of the scoliosis. In a second time, the histological changes at apical vertical body level and the adjacent discs were evaluated preand post-correction. Results: A mean 81.5◦ kyphoscoliosis was gradually induced. In the control group, after cutting the suture, an initial reduction in the deformity was observed, but later it remained stable throughout the time (54◦ at two weeks). In the Nitinol group, a gradual reduction was observed in the scoliosis angle value, to a mean of 8.7◦ at two weeks. The curvature of the apical vertebral body and adjacent discs were partially corrected after two weeks of correcting the deformity. Conclusion: This scoliosis model has demonstrated the efficacy of a straight Nitinol wire fixed to the spinal column in the gradual correction of kyphoscoliosis and in the changes in its adjacent structures (AU)

[Modulation of scoliotic spine growth in experimental animals using intelligent metal bars]. / Modulación del crecimiento de columnas escolióticas en animales de experimentación mediante el uso de barras de metal inteligente.

OBJECTIVE: To create an experimental structural scoliosis model in mice to evaluate the efficacy of shape-memory metals to gradually correct the deformity over time. MATERIAL AND METHOD: Experimental scoliosis was generated in 3 week-old mice by means of a suture between the left scapula and pelvis for 8 weeks. They were then randomised into two groups: a control group, in which the suture was cut, and another, in those that also had a Nitinol straight memory-wire implant fixed to the column. Serial X-rays were performed to determine the efficacy of the Nitinol in the correction of the scoliosis. In a second time, the histological changes at apical vertical body level and the adjacent discs were evaluated pre- and post-correction. RESULTS: A mean 81.5° kyphoscoliosis was gradually induced. In the control group, after cutting the suture, an initial reduction in the deformity was observed, but later it remained stable throughout the time (54° at two weeks). In the Nitinol group, a gradual reduction was observed in the scoliosis angle value, to a mean of 8.7° at two weeks. The curvature of the apical vertebral body and adjacent discs were partially corrected after two weeks of correcting the deformity. CONCLUSION: This scoliosis model has demonstrated the efficacy of a straight Nitinol wire fixed to the spinal column in the gradual correction of kyphoscoliosis and in the changes in its adjacent structures.

[Growing rods in early-onset scoliosis. Do they really help to control the deformity and spinal and thoracic growth?]. / Barras de crecimiento en escoliosis de inicio precoz ¿Permiten realmente el control de la deformidad y el crecimiento vertebral y torácico?

OBJECTIVE: To determine the efficacy of growing rods in the treatment of early onset scoliosis. MATERIAL AND METHODS: A total of 32 patients were treated using fusion techniques that included double growing rods and Vertical Expandable Prosthetic Titanium Ribs (VEPTR), in our Early Onset Scoliosis Centre between 2004 and 2011. After analysing the clinical histories and x-rays, 20 patients were included due to meeting the inclusion criteria. All patients had previously received conservative treatment with cranial traction and a series of plasters/corsets. The deformity was analysed before and after the initial surgery, and in successive tightenings, using the x-rays of the coronal and sagittal planes by means of the Cobb angle, as well as the longitudinal and coronal growth of the thorax, and the growth of the spinal column. A series of 188 x-rays of 53 patients with cystic fibrosis were studied in order to perform a comparative analysis with the patients with early-onset scoliosis. RESULTS: There was significant improvement in the angle (Cobb and kyphosis) and linear parameters (T1-S1 distance, T1-T12 distance, and coronal width of the thorax) after the initial surgery, but the successive tightenings had a minimal beneficial effect, losing effectiveness over a period of time. The patients with early-onset scoliosis showed a lower growth of the thorax compared to the patients with cystic fibrosis. DISCUSSION: Treatment of early-onset scoliosis with expandable devices is mainly beneficial with the initial procedure and the first tightenings, but shows a loss of efficacy over a period time.

Barras de crecimiento en escoliosis de inicio precoz ¿Permiten realmente el control de la deformidad y el crecimiento vertebral y torácico? / Growing rods in early-onset scoliosis. Do they really help to control the deformity and spinal and thoracic growth?

Objetivo. Determinar la eficacia de las barras de crecimiento en el tratamiento de la escoliosis de inicio precoz. Material y métodos. Entre 2004 y 2011, un total de 32 pacientes fueron intervenidos en nuestro centro de escoliosis de inicio precoz mediante técnicas sin fusión (barras de crecimiento dobles y VEPTR). De ellos, analizamos prospectivamente la historia clínica y las radiografías de 20 pacientes que cumplen los criterios de inclusión. Todos los pacientes habían recibido previamente tratamiento conservador con tracción craneal y yesos/corsés seriados. En cada radiografía (preoperatoria y postoperatoria de la cirugía inicial y de los sucesivos retensados) analizamos la deformidad en los planos coronal y sagital mediante el ángulo de Cobb, el crecimiento longitudinal y coronal del tórax, y el crecimiento de la columna vertebral. Se estudian 188 radiografías de tórax seriadas de 53 pacientes con fibrosis quística para hacer un análisis comparativo con los pacientes con escoliosis de inicio precoz. Resultados. La mejora de los parámetros angulares (Cobb y cifosis) y lineales (distancia T1-S1, distancia T1-T12 y anchura coronal del tórax) fue significativa con la cirugía inicial, pero los sucesivos retensados tuvieron un mínimo efecto beneficioso, perdiendo eficacia a lo largo del tiempo. Comparativamente con los pacientes con fibrosis quística, el crecimiento del tórax es menor en los pacientes con escoliosis de inicio precoz. Discusión. El tratamiento de la escoliosis de inicio precoz con sistemas expansibles resulta beneficioso fundamentalmente en el procedimiento inicial y primeros retensados, demostrando una pérdida de eficacia a lo largo del tiempo (AU)

Objective. To determine the efficacy of growing rods in the treatment of early onset scoliosis. Material and methods. A total of 32 patients were treated using fusion techniques that included double growing rods and Vertical Expandable Prosthetic Titanium Ribs (VEPTR), in our Early Onset Scoliosis Centre between 2004 and 2011. After analysing the clinical histories and x-rays, 20 patients were included due to meeting the inclusion criteria. All patients had previously received conservative treatment with cranial traction and a series of plasters/corsets. The deformity was analysed before and after the initial surgery, and in successive tightenings, using the x-rays of the coronal and sagittal planes by means of the Cobb angle, as well as the longitudinal and coronal growth of the thorax, and the growth of the spinal column. A series of 188 x-rays of 53 patients with cystic fibrosis were studied in order to perform a comparative analysis with the patients with early-onset scoliosis. Results. There was significant improvement in the angle (Cobb and kyphosis) and linear parameters (T1-S1 distance, T1-T12 distance, and coronal width of the thorax) after the initial surgery, but the successive tightenings had a minimal beneficial effect, losing effectiveness over a period of time. The patients with early-onset scoliosis showed a lower growth of the thorax compared to the patients with cystic fibrosis. Discussion. Treatment of early-onset scoliosis with expandable devices is mainly beneficial with the initial procedure and the first tightenings, but shows a loss of efficacy over a period time (AU)

Resultados funcionales tras la reparación artroscópica de roturas masivas del manguito rotador: influencia de la aplicación de plasma rico en plaquetas asociado a fibrina / Functional results after arthroscopic repair of massive rotator cuff tears; influence of the application platelet-rich plasma combined with fibrin

Objetivo. El objetivo de este trabajo es investigar si la aplicación de plasma rico en plaquetas con alto contenido en fibrina a la zona de reparación de roturas masivas del manguito de los rotadores tratadas mediante técnicas artroscópicas mejora los resultados funcionales y disminuye el índice de reroturas. Material y método. 28 enfermos (20 mujeres y 8 varones) con una edad media de 65 años (rango: 53 a 78) diagnosticados de una rotura masiva del manguito rotador (dos tendones afectados>5cm) fueron incluidos en este estudio prospectivo y aleatorizado. En todos los enfermos se realizó una reparación completa artroscópica del manguito rotador con técnica de una hilera. En 14 pacientes una vez finalizada la reparación se aplicó en la zona de transición osteotendinosa un concentrado de plasma rico en plaquetas y alto contenido de fibrina, mientras que en 14 enfermos se realizó la reparación sin ningún aporte de factores de crecimiento. Se evaluaron los resultados funcionales con la escala de Constant al año de la intervención, así como una artro-RM para comprobar la integridad del tendón reparado. Resultados. No hubo complicaciones ni reoperaciones en ninguno de los dos grupos. El Constant preoperatorio mejoró 30 puntos en el grupo sin PRP y 26 puntos en el grupo con PRP, sin diferencias entre ambos grupos. En el estudio de artro-RM 9 pacientes mostraban integridad de la reparación (32%), 4 presentaban una fuga de contraste y 15 una rerotura franca. No se encontraron diferencias en índice de reroturas entre el grupo en el que se aplicó plasma rico en plaquetas y en el que no. Conclusiones. La reparación artroscópica de roturas masivas del manguito rotador ofrece unos resultados clínicos satisfactorios a pesar de un elevado índice de nuevas roturas. La aplicación de plasma rico en plaquetas no mejora los resultados clínicos ni disminuye el índice de reroturas (AU)

Objective. The aim of this work is to investigate whether the application of platelet-rich plasma (PRP) with a high fibrin content in the repair area of massive rotator cuff tears treated using arthroscopic techniques improves the functional results and decreases the number of re-tears. Material and method. This prospective, randomised study included 28 patients (20 females and 8 males) with a mean age of 65 years (range: 53 to 78) and diagnosed with a massive rotator cuff tear (two tendons affected, >5cm). A complete single row arthroscopic repair of the rotator cuff was performed on all patients. A concentrate of platelet rich plasma with a high fibrin content was applied to the osteotendinous transition area in 14 patients after the operation, whilst in the other 14 patients the repair was performed without any growth factor support. The functional results were evaluated with the Constant scale, as well as an arthro-MRI to check the integrity of the repaired tendon one year after the operation. Results. There were no complications or repeat operations in any of the two groups. The pre-operative Constant results improved 30 points in the group without PRP and 26 points in the group with PRP, with no significant differences between both groups. In the arthro-MRI study, integrity of the repair was observed in 9 (32%) patients, whilst 4 had a contrast leak and 15 a clear re-tear. No differences were found in the number of re-tears between the group in which the platelet-rich plasma was applied and in the one where it was not applied. Conclusions. The arthroscopic repair of massive rotator cuff tears gives clinically satisfactory results, despite a high rate of new tears. The application of platelet-rich plasma did not improve the clinic results or decrease the number of re-tears (AU)

Implantación del componente rotuliano en la artroplastia total de rodilla: situación actual / Implantation of the patellar component in the total arthroplasty of the knee: current situation

Introducción: Implantar o no el componente rotuliano (CR) en prótesis de rodilla es un tema controvertido. Material y método: Para intentar clarificar esta controversia hemos revisado artículos de evidencia científica grados 1 y 2. Resultados: Sin CR, el porcentaje de dolor anterior de rodilla oscila entre17–69% frente al 5,3–37% cuando se coloca el CR. Sin CR, el porcentaje de reoperación va de 0–20%, y es de 0–13% cuando se implanta el CR. Un estudio prospectivo ha demostrado que la clasificación de Outerbridge sirve para decidir si implantar o no el CR. Conclusiones: La controversia sigue sin estar resuelta. Para algunos autores es mejor colocar siempre el CR. Sin embargo, otros señalan que no es necesario colocar el CR en los grados i, ii y iii de Outerbridge, y es aconsejable hacerlo en los grados iv (AU)

Introduction: Implanting or not implanting the patellar component (PC) in knee prosthesis (TKP) is a controversial subject. Material and method: In an attempt to clarify this controversy, we have reviewed grade 1 and 2 scientific evidence articles. Results: The percentage of anterior knee pain without PC ranges from 17% to 69% versus 5.3&%#x02013;37% when the PC is placed. Without PC, the percentage of reoperation goes from 0% to 20%, this being from 0% to 13% when the PC is implanted. A prospective study has demonstrated that the Outerbridge classification serves to decide on whether to perform a PC implant or not. Conclusions: The controversial is still unsolved. For some authors, it is better to always place a PC. However, others state that it is not necessary to do so in Outerbridge grades I, II and III, being recommendable to do so in grade IV (AU)

Resultados del tratamiento de las fracturas de radio distal con placa volar de ángulo fijo / Results of the treatment of distal radius fractures with fixed-angled volar plates

Objetivo: Determinar los resultados funcionales de pacientes con fractura del radio distal desplazada e inestable tratados mediante placa volar. Pacientes y metodología: Revisamos 34 pacientes consecutivos tratados con placa volar de ángulo fijo que fueron evaluados en la última visita de seguimiento utilizando las escalas DASH y Mayo Wrist Score. El seguimiento medio fue de 28 meses (12-70). Resultados: Las radiografías del postoperatorio inmediato mostraron una discrepancia radiocubital media de 1,5 mm, la inclinación radial media fue de 15º y la inclinación volar media de 5º. En el momento de la consolidación de la fractura, la discrepancia radiocubital media fue de 0,8 mm, la inclinación radial media fue de 13º y la inclinación volar media de 5º. La movilidad media de la muñeca afecta era de 65º de flexión, 60º de extensión, 21º de desviación radial y 34º de desviación cubital. La pronación media del lado afecto fue del 90% de la del lado contralateral, la supinación comparativa fue del 91%, y la fuerza de agarre en el lado afecto era de 16,85 y en el lado no afecto de 21,04. Al final del seguimiento, el valor medio de la escala DASH fue de 13,53 y se obtuvieron 11 resultados excelentes, 15 buenos, 5 aceptables y 3 pobres utilizando la escala de Mayo. Conclusión: El tratamiento de las fracturas de radio distal mediante placa volar en una alternativa segura, que permite una reducción estable, con buenos resultados funcionales y radiológicos con pocas complicaciones (AU)

Purpose: to determine the functional outcomes of patients treated with volar plating for displaced and unstable distal radius fractures. Materials and methods: we reviewed the records of 34 consecutive patients treated with volar plating in our institution. Outcomes were evaluated at the latest follow-up examination with the Disabilities of the Arm, Shoulder and Hand score and the Mayo Wrist Score. The average follow-up period was 28 months (range, 12-70). Results: radiographs in the immediate postoperative period showed a mean radial height of 1,5 mm, mean radial inclination was 15º and mean volar tilt was 5º.At fracture healing the mean radial height was 0,8 mm, mean radial inclination was 13º and mean volar tilt was 5º. The average affected wrist range of motion consisted of 65º of flexion (range, 35-90), 60º of extension (range, 30-90), 21º of radial deviation (range, 0-60), and 34º of ulnar deviation (range, 10-60). On average the pronation was 90,32% of the pronation of the contralateral extremity, the comparative supination was 91%, and the grip strength in the affected side was 16,85 and in the contralateral side was 21,04. The average score on the DASH was 13,53 at the latest follow-up evaluation, and the Mayo Wrist Score reported 11 excellent outcomes, 15 good, 5 fair and 3 poor outcomes. Conclusions: Treatment of distal radius fractures by means of a volar plate is a safe alternative that permits a stable reduction. Good functional and radiological results can be obtained with few complications (AU)