A wireless platform for in vivo measurement of resistance properties of the gastrointestinal tract

Active locomotion of wireless capsule endoscopes has the potential to improve the diagnostic yield of this painless technique for the diagnosis of gastrointestinal tract disease. In order to design effective locomotion mechanisms, a quantitative measure of the propelling force required to effectively move a capsule inside the gastrointestinal tract is necessary. In this study, we introduce a novel wireless platform that is able to measure the force opposing capsule motion, without perturbing the physiologic conditions with physical connections to the outside of the gastrointestinal tract. The platform takes advantage of a wireless capsule that is magnetically coupled with an external permanent magnet. A secondary contribution of this manuscript is to present a real-time method to estimate the axial magnetic force acting on a wireless capsule manipulated by an external magnetic field. In addition to the intermagnetic force, the platform provides real-time measurements of the capsule position, velocity, and acceleration. The platform was assessed with benchtop trials within a workspace that extends 15 cm from each side of the external permanent magnet, showing average error in estimating the force and the position of less than 0.1 N and 10 mm, respectively. The platform was also able to estimate the dynamic behavior of a known resistant force with an error of 5.45%. Finally, an in vivo experiment on a porcine colon model validated the feasibility of measuring the resistant force in opposition to magnetic propulsion of a wireless capsule

SMAC — A Modular Open Source Architecture for Medical Capsule Robots

The field of Medical Capsule Robots (MCRs) is gaining momentum in the robotics community, with applications spanning from abdominal surgery to gastrointestinal (GI) endoscopy. MCRs are miniature multifunctional devices usually constrained in both size and on-board power supply. The design process for MCRs is time consuming and resource intensive, as it involves the development of custom hardware and software components. In this work, we present the STORM Lab Modular Architecture for Capsules (SMAC), a modular open source architecture for MCRs aiming to provide the MCRs research community with a tool for shortening the design and development time for capsule robots. The SMAC platform consists of both hardware modules and firmware libraries that can be used for developing MCRs. In particular, the SMAC modules are miniature boards of uniform diameter (i.e., 9.8 mm) that are able to fulfill five different functions: signal coordination combined with wireless data transmission, sensing, actuation, powering and vision/illumination. They are small in size, low power, and have reconfigurable software libraries for the Hardware Abstraction Layer (HAL), which has been proven to work reliably for different types of MCRs. A design template for a generic SMAC application implementing a robust communication protocol is presented in this work, together with its finite state machine abstraction, capturing all the architectural components involved. The reliability of the wireless link is assessed for different levels of data transmission power and separation distances. The current consumption for each SMAC module is quantified and the timing of a SMAC radio message transmission is characterized. Finally, the applicability of SMAC in the field of MCRs is discussed by analysing examples from the literature

Cerebral palsy rehabilitation: comparison between italian child centred andcanadian family centred healthcare models

ABSTRACT Background Among disabling pathologies, that affect children from birth, Cerebral Palsy (CP) is the most important for frequency and multiplicity of associated disorders. Care of CP requires a long and complex rehabilitation process that involves healthcare services, educational facilities and social agencies, but above all family members (SCPE 2000). In Canada, family has decision-making power in childcare, which includes rehabilitation treatments and socio-educational interventions. This family-centred approach presupposes a shared responsibility between caregivers and family in planning and applying child rehabilitation therapies. In Italy, “Recommendations for cerebral palsy rehabilitation” provide for a drafting of an Individual Rehabilitation Plan (PRI), according to the ICF-CY model. Designing the therapeutic project (PRI) is the physician’s responsibility, who subsequently involves the family in reaching objectives, timing interventions, realising setting modalities and measuring outcomes. This approach is child-centred, however with the participatory involvement of family. The aim of this study is to compare perception of Italian and Canadian families regarding these two different healthcare models in CP rehabilitation. Method Data from 219 MPOC-20 and 75 MPOC-SP questionnaires were collected from child healthcare services in Emilia Romagna Region and compared to Ontario province data published by CanChild. Results By comparing MPOC-20 and MPOC-SP results obtained in Emilia Romagna and Ontario, we found that average values of various domains reveal few differences. The only domain showing lower results for Emilia Romagna concerned child-specific information supply (Emilia Romagna average is 4.69, Ontario is 5.23). On the contrary, for all the remaining domains, Emilia Romagna had higher averages. Considering physiotherapist questionnaires, we found higher satisfaction levels regarding treatment in Ontario. The greatest difference related to the “Providing General Information” domain: parental perception; Emilia Romagna average was 3.74, while Ontario’s average was 4.68. For the domain “Showing Interpersonal Sensitivity”, satisfaction was high for both countries: 5.76 in Emilia Romagna, 5.83 in Ontario. Discussion Communication regarding general aspects, pathology and treatment information must be improved in Emilia Romagna in order to increase satisfaction and cooperation between families and healthcare professionals. Conclusions The study results allow us to conclude that Italian and Canadian family satisfaction of healthcare quality is quite similar, and that the Italian model of CP rehabilitation, with a few slight modifications, could be judged competitive. An organizational model focused on child, constantly involving family in care programs, which we could coin "Child-and-Family-Centred approach", would seem to be the key to a higher quality, efficacy and efficiency service

Jacobian-Based Iterative Method for Magnetic Localization in Robotic Capsule Endoscopy

The purpose of this study is to validate a Jacobian-based iterative method for real-time localization of magnetically controlled endoscopic capsules. The proposed approach applies finite-element solutions to the magnetic field problem and least-squares interpolations to obtain closed-form and fast estimates of the magnetic field. By defining a closed-form expression for the Jacobian of the magnetic field relative to changes in the capsule pose, we are able to obtain an iterative localization at a faster computational time when compared with prior works, without suffering from the inaccuracies stemming from dipole assumptions. This new algorithm can be used in conjunction with an absolute localization technique that provides initialization values at a slower refresh rate. The proposed approach was assessed via simulation and experimental trials, adopting a wireless capsule equipped with a permanent magnet, six magnetic field sensors, and an inertial measurement unit. The overall refresh rate, including sensor data acquisition and wireless communication was 7 ms, thus enabling closed-loop control strategies for magnetic manipulation running faster than 100 Hz. The average localization error, expressed in cylindrical coordinates was below 7 mm in both the radial and axial components and 5° in the azimuthal component. The average error for the capsule orientation angles, obtained by fusing gyroscope and inclinometer measurements, was below 5°

Toward Rapid Prototyping of Miniature Capsule Robots

Minimally invasive robotic surgery techniques are becoming popular thanks to their enhanced patient benefits, including shorter recovery time, better cosmetic results and reduced discomforts. Less invasive procedures would be achieved with the use of Medical Capsule Robots (MCRs). These devices are characterized by low power requirements and small dimensions as well as uncompromising safety. MCRs operate wirelessly in abdominal Minimally Invasive Surgery (MIS) and Natural Orifice Transluminal Endoscopic Surgery (NOTES) or in the Gastrointestinal (GI) tract. The design process of MCRs, however, is expensive and time consuming. A platform for rapid prototyping MCRs is needed so that MCR researchers can reduce development costs and spend more time in studying innovative MCR applications. In this work, we introduce an open source modular platform geared toward rapid prototyping MCRs. To speed up the prototyping process, the MCR is programmed using TinyOS instead of bare-bone C. We present the hardware architecture of the platform, and the motivation for using TinyOS. To show the viability of TinyOS, we present results from an experiment involving sensing, actuation and wireless communication. This work lays the foundation for our future goal of building an integrated design environment for the design, analysis and simulation of MCRs

Closed-Loop Control of Local Magnetic Actuation for Robotic Surgical Instruments

We propose local magnetic actuation (LMA) as an approach to robotic actuation for surgical instruments. An LMA actuation unit consists of a pair of diametrically magnetized single-dipole cylindrical magnets, working as magnetic gears across the abdominal wall. In this study, we developed a dynamic model for an LMA actuation unit by extending the theory proposed for coaxial magnetic gears. The dynamic model was used for closed-loop control, and two alternative strategies-using either the angular velocity at the motor or at the load as feedback parameter-were compared. The amount of mechanical power that can be transferred across the abdominal wall at different intermagnetic distances was also investigated. The proposed dynamic model presented a relative error below 7.5% in estimating the load torque from the system parameters. Both the strategies proposed for closed-loop control were effective in regulating the load speed with a relative error below 2% of the desired steady-state value. However, the load-side closed-loop control approach was more precise and allowed the system to transmit larger values of torque, showing, at the same time, less dependence from the angular velocity. In particular, an average value of 1.5 mN·m can be transferred at 7 cm, increasing up to 13.5 mN·m as the separation distance is reduced down to 2 cm. Given the constraints in diameter and volume for a surgical instrument, the proposed approach allows for transferring a larger amount of mechanical power than what would be possible to achieve by embedding commercial dc motors

Wireless tissue palpation: Head characterization to improve tumor detection in soft tissue

For surgeons performing open procedures, the sense of touch is a valuable tool to directly access buried structures and organs, to identify their margins, detect tumors, and prevent undesired cuts. Minimally invasive surgical procedures provide great benefits for patients; however, they hinder the surgeon's ability to directly manipulate the tissue. In our previous work, we developed a Wireless Palpation Probe (WPP) to restore tissue palpation in Minimally Invasive Surgery (MIS) by creating a real-time stiffness distribution map of the target tissue. The WPP takes advantage of a field-based magnetic localization algorithm to measure its position, orientation, and tissue indentation depth, in addition to a barometric sensor measuring indentation tissue pressure. However, deformations of both the tissue and the silicone material used to cover the pressure sensors introduce detrimental nonlinearities in sensor measurements. In this work, we calibrated and characterized different diameter WPP heads with a new design allowing exchangeability and disposability of the probe head. Benchtop trials showed that this method can effectively reduce error in sensor pressure measurements up to 5% with respect to the reference sensor. Furthermore, we studied the effect of the head diameter on the device's spatial resolution in detecting tumor simulators embedded into silicone phantoms. Overall, the results showed a tumor detection rate over 90%, independent of the head diameter, when an indentation depth of 5 mm is applied on the tissue simulator

A Magnetic Drug Delivery Capsule Based on a Coil Actuation Mechanism

Current Wireless Capsule Endoscopic systems (WCE) provide only diagnostic tools, but in the future, advanced functionalities such as controllable drug delivery could be available for clinicians. This work introduces a Magnetic Drug Delivery Capsule (MDDC). The MDCC is based on a coil actuation mechanism that enables the deployment of a drug chamber from the device body. In this work, we present the prototype design and the results of bench trials that demonstrated the device ability to trigger the drug deployment by characterizing the magnetic field and resulting force

Wireless Tissue Palpation for Intraoperative Detection of Lumps in the Soft Tissue

In an open surgery, identification of precise margins for curative tissue resection is performed by manual palpation. This is not the case for minimally invasive and robotic procedures, where tactile feedback is either distorted or not available. In this paper, we introduce the concept of intraoperative wireless tissue palpation. The wireless palpation probe (WPP) is a cylindrical device (15 mm in diameter, 60 mm in length) that can be deployed through a trocar incision and directly controlled by the surgeon to create a volumetric stiffness distribution map of the region of interest. This map can then be used to guide the tissue resection to minimize healthy tissue loss. The wireless operation prevents the need for a dedicated port and reduces the chance of instrument clashing in the operating field. The WPP is able to measure in real time the indentation pressure with a sensitivity of 34 Pa, the indentation depth with an accuracy of 0.68 mm, and the probe position with a maximum error of 11.3 mm in a tridimensional workspace. The WPP was assessed on the benchtop in detecting the local stiffness of two different silicone tissue simulators (elastic modulus ranging from 45 to 220 kPa), showing a maximum relative error below 5%. Then, in vivo trials were aimed to identify an agar-gel lump injected into a porcine liver and to assess the device usability within the frame of a laparoscopic procedure. The stiffness map created intraoperatively by the WPP was compared with a map generated ex vivo by a standard uniaxial material tester, showing less than 8% local stiffness error at the site of the lump

Systematic Design of edical Capsule Robots

Medical capsule robots that navigate inside the body as diagnostic and interventional tools are an emerging and challenging research area within medical CPSs. These robots must provide locomotion, sensing, actuation, and communication within severe size, power, and computational constraints. This paper presents the first effort for an open architecture, platform design, software infrastructure, and a supporting modular design environment for medical capsule robots to further this research area