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Communication Dans Un Congrès Année : 2018

A volume-based aspiration method to estimate in-vivo soft tissues stiffness: evaluation of the device with silicone samples

Résumé

Computer Assisted Medical Interventions (CAMI) involving soft tissues require devices that model such tissues in order to estimate the way they are going to be deformed and/or resected by the surgical gesture. The corresponding biomechanical patient-specific models require an estimation of the constitutive behavior of the soft tissues. Since the mechanical behavior of living tissues varies between in-vivo and ex-vivo conditions, it is important for the CAMI devices to offer an in-vivo estimation with non-traumatic measurements that should undergo sterile conditions. For this purpose, among all the methods proposed in the literature, aspiration/suction is the most widely used technique due to its simplicity and robustness. For such a technique, a device with a hole is put in contact with the soft tissue while a negative pressure aspires part of this tissue. Knowing the relationship between the negative pressure and the aspired tissue height, an inverse problem is then solved to identify the material mechanical properties. In the literature, the apex height is usually measured with a camera and a mirror or a prism, which induces design difficulties, in particular in regards on the required sterilization process for in-vivo measurements. This paper introduces a new method that replaces the optical apex height measurement with a measurement of the aspired tissue volume. The method is referred to as "rate-based method". The camera, mirror and all electronic parts are not required, which makes our device the simplest, lightest and cheapest one could achieve. In particular, this simplification enables the system to meet the severe sterilizations constraints that can be present for some surgeries. Indeed, the proposed device is only composed of a cylindrical plastic chamber (with a hole at its basis), some connection tubes, a syringe pump, a manometer and an aspiration chamber. The idea is to aspirate the tissue inside the chamber using the syringe pump, while measuring the negative pressure and the corresponding removed volume. Such a volume is due to both the aspired tissue volume inside the chamber and the volume changes in the device (air expansion and elasticity of the connections, tubes, syringe, etc.). An off-line calibration process is defined to differentiate the volume changes due to tissue aspiration from the volume changes due to the compressibility of the device (tubes, connections, syringe).
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Dates et versions

hal-01930219 , version 1 (21-11-2018)

Identifiants

  • HAL Id : hal-01930219 , version 1

Citer

Seyed Ali Elahi, Nathanaël Connesson, Yohan Payan. A volume-based aspiration method to estimate in-vivo soft tissues stiffness: evaluation of the device with silicone samples. 16th European Mechanics of Materials Conference (EMMC 2016), Mar 2018, Nantes, France. pp.464-465. ⟨hal-01930219⟩
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