Toward a robust swallowing detection for an implantable active artificial larynx: a survey.

Total laryngectomy consists in the removal of the larynx and is intended as a curative treatment for laryngeal cancer, but it leaves the patient with no possibility to breathe, talk, and swallow normally anymore. A tracheostomy is created to restore breathing through the throat, but the aero-digestive tracts are permanently separated and the air no longer passes through the nasal tracts, which allowed filtration, warming, humidification, olfaction, and acceleration of the air for better tissue oxygenation. As for phonation restoration, various techniques allow the patient to talk again. The main one consists of a tracheo-esophageal valve prosthesis that makes the air passes from the esophagus to the pharynx, and makes the air vibrate to allow speech through articulation. Finally, swallowing is possible through the original tract as it is now isolated from the trachea. Yet, many methods exist to detect and assess a swallowing, but none is intended as a definitive restoration technique of the natural airway, which would permanently close the tracheostomy and avoid its adverse effects. In addition, these methods are non-invasive and lack detection accuracy. The feasibility of an effective early detection of swallowing would allow to further develop an implantable active artificial larynx and therefore restore the aero-digestive tracts. A previous attempt has been made on an artificial larynx implanted in 2012, but no active detection was included and the system was completely mechanic. This led to residues in the airway because of the imperfect sealing of the mechanism. An active swallowing detection coupled with indwelling measurements would thus likely add a significant reliability on such a system as it would allow to actively close an artificial larynx. So, after a brief explanation of the swallowing mechanism, this survey intends to first provide a detailed consideration of the anatomical region involved in swallowing, with a detection perspective. Second, the swallowing mechanism following total laryngectomy surgery is detailed. Third, the current non-invasive swallowing detection technique and their limitations are discussed. Finally, the previous points are explored with regard to the inherent requirements for the feasibility of an effective swallowing detection for an artificial larynx. Graphical Abstract.

Modelling and characterization of an instrumented medical needle in sight of new microsensor design for its insertion guidance.

A needle used in in-vivo medical percutaneous procedures is subject to auto-deflection coming from its interactions with inhomogeneous and anisotropic tissues and organs in human body. In this paper we present the modelling and the characterization of microsensors glued on a medical needle in order to detect its real-time deflection by measuring strain variations on the needle. A first prototype has been developed by gluing metal foil strain gauges to the surface of a biopsy needle. The characterization of this prototype is carried out in comparison with theoretical analysis and finite element method (FEM) modelling. Results acquired through these different methods show an excellent conformity and confirm the feasibility of an instrumented medical device.

Rectus abdominis electromyography and MechanoMyoGraphy comparison for the detection of cough.

We recently developed a novel active implant for the treatment of severe stress urinary incontinence. This innovative medical device has been developed with the main purpose of reducing the mean urethral occlusive pressure of the current prosthesis. This goal is achieved by detecting circumstances implying either high or low intra-abdominal pressures by a single 3-axis accelerometer. In fact, posture and activity of the patient are monitored in real time. We investigated in this study the possibility of detecting cough events (one of the main causes of urine loss in incontinent patient) by MechanoMyoGraphy (MMG) of the Rectus Abdominis (RA) using the same accelerometer. We compared MMG signal detection characteristics (burst onset times and RMS values) to the method of reference, the ElectroMyoGraphy (EMG). It is shown that detection of cough effort by MMG presents lower performances, mostly in terms of cough anticipation, than EMG detection. However, MMG still remains a good option for an implantable system comparing to implantable EMG disadvantages.