Soft, flexible pressure sensors for pressure monitoring under large hydrostatic pressure and harsh ocean environments.

Traditional rigid ocean pressure sensors typically require protection from bulky pressure chambers and complex seals to survive the large hydrostatic pressure and harsh ocean environment. Here, we introduce soft, flexible pressure sensors that can eliminate such a need and measure a wide range of hydrostatic pressures (0.1 MPa to 15 MPa) in environments that mimic the ocean, achieving small size, high flexibility, and potentially low power consumption. The sensors are fabricated from lithographically patterned gold thin films (100 nm thick) encapsulated with a soft Parylene C film and tested in a customized pressure vessel under well-controlled pressure and temperature conditions. Using a rectangular pressure sensor as an example, the resistance of the sensor is found to decrease linearly with the increase of the hydrostatic pressure from 0.1 MPa to 15 MPa. Finite element analysis (FEA) reveals the strain distributions in the pressure sensor under hydrostatic pressures of up to 15 MPa. The effect of geometry on sensor performance is also studied, and radially symmetric pressure sensors (like circular and spike-shaped) are shown to have more uniform strain distributions under large hydrostatic pressures and, therefore, have a potentially enhanced pressure measurement range. Pressure sensors of all geometries show high consistency and negligible hysteresis over 15 cyclic tests. In addition, the sensors exhibit excellent flexibility and operate reliably under a hydrostatic pressure of 10 MPa for up to 70 days. The developed soft pressure sensors are promising for integration with many platforms including animal tags, diver equipment, and soft underwater robotics.

Tratamiento de la lesión aguda del tendón de Aquiles mediante una técnica mínimamente invasiva sin nudos. Rehabilitación y carga de peso inmediata / Acute achilles tendon injury treatment using a minimally invasive knotless technique. Rehabilitation and immediate weight bearing

Introducción: Las técnicas quirúrgicas modernas buscan rehabilitar en forma temprana para una recuperación en menor tiempo. Las técnicas mínimamente invasivas son una opción para lograrlo. Objetivo: Evaluar la capacidad de comenzar una rehabilitación y la carga de peso en el posoperatorio inmediato utilizando una técnica mínimamente invasiva sin nudos y la evolución a los 6 meses de la cirugía. materiales y métodos: Se realizaron 10 reparaciones quirúrgicas de lesiones agudas del tendón de Aquiles con una técnica mínimamente invasiva sin nudo. Se utilizó el sistema combinado (PARS ­ SpeedBridgeTM original. A las 48 h se permitió la carga completa de forma progresiva, según tolerancia. Se evaluó el resultado final a los 6 meses utilizando el puntaje ATRS. Resultados: En promedio los pacientes tardaron 14 días en deambular sin muletas. Todos comenzaron la rehabilitación con movilidad activa y pasiva del tobillo durante la primera semana posoperatoria. El puntaje ATRS promedio fue de 79 (rango 60-90). Conclusión: Esta técnica ha demostrado ser una excelente opción quirúrgica en las lesiones agudas del tendón de Aquiles de media sustancia, pero no fue posible comenzar con la carga de peso inmediata debido al dolor o temor del paciente, pero sí con la rehabilitación dentro de la primera semana posquirúrgica. Nivel de Evidencia: IV

Introduction: Modern surgical techniques seek to rehabilitate early for recovery in less time. Minimally invasive techniques are one option to accomplish this. Objective: To evaluate the ability to start rehabilitation and weight bearing in the immediate post-operative period and the evolution at 6 months postoperative using a minimally invasive knotless technique. materials and methods: 10 surgical repairs of acute Achilles tendon injuries were performed with a minimally invasive technique. The original Arthrex combination system (PARS - SpeedBridgeTM) was used. After 48 hours, weight bearing was progressively allowed according to tolerance. The final outcome at 6 months was evaluated using the ATRS score. Results: On average, patients took 14 days to walk without crutches. All began rehabilitation with active and passive ankle range of motion during the first postoperative week. The average ATRS score was 79 points (between 60 and 90 points). Conclusion: This technique has proven to be an excellent surgical option in acute midsubstance Achilles tendon injuries. The patients were able to start rehabilitation within the first postoperative week, whereas immediate weight bearing was not possible, due to the patients ́ pain or fear. Level of Evidence: IV