Giuseppe Tortora

Swallowable Medical Devices for Diagnosis and Surgery: The State of the Art

Abstract The first wireless camera pills created a revolutionary new perspective for engineers and physicians, demonstrating for the first time the feasibility of achieving medical objectives deep within the human body from a swallowable, wireless platform. The approximately 10 years since the first camera pill has been a period of great innovation in swallowable medical devices. Many modules and integrated systems have been devised to enable and enhance the diagnostic and even robotic capabilities of capsules working within the gastrointestinal (GI) tract. This article begins by reviewing the motivation and challenges of creating devices to work in the narrow, winding, and often inhospitable GI environment. Then the basic modules of modern swallowable wireless capsular devices are described, and the state of the art in each is discussed. This article is concluded with a perspective on the future potential of swallowable medical devices to enable advanced diagnostics beyond the capability of human visual perception, and even to directly deliver surgical tools and therapy non-invasively to interventional sites deep within the GI tract.

Wireless powering for a self-propelled and steerable endoscopic capsule for stomach inspection

This paper describes the integration of an active locomotion module in a wirelessly powered endoscopic capsule. The device is a submersible capsule optimized to operate in a fluid environment in a liquid-distended stomach. A 3D inductive link is used to supply up to 400mW to the embedded electronics and a set of 4 radio-controlled motor propellers. The design takes advantage of a ferrite-core in the receiving coil-set. This approach significantly improves the coupling with the external field source with respect to earlier work by the group. It doubles the power that can be received with a coreless coil-set under identical external conditions. The upper limit of the received power was achieved complying with the strict regulations for safe exposure of biological tissue to variable magnetic fields. The wireless transferred power was proven to be sufficient to achieve the speed of 7cm/s in any directions. An optimized locomotion strategy was defined which limits the power consumption by running only 2 motors at a time. A user interface and a joystick controller allow to fully drive the capsule in an intuitive manner. The device functionalities were successfully tested in a dry and a wet environment in a laboratory set-up.

Propeller-based wireless device for active capsular endoscopy in the gastric district

An innovative approach to active locomotion for capsular endoscopy in the gastric district is reported in this paper. Taking advantage of the ingestion of 500 ml of transparent liquid by the patient, an effective distension of the stomach is safely achieved for a timeframe of approximately 30 minutes. Given such a scenario, an active swallowable capsule able to navigate inside the stomach thanks to a four propeller system has been developed. The capsule is 15 mm in diameter and 30 mm in length, and it is composed of a supporting shell containing a wireless microcontroller, a battery and four motors. The motors enable the rotation of propellers located in the rear side of the device, thus obtaining a reliable locomotion and steering of the capsule in all directions in a liquid. The power consumption has been properly optimized in order to achieve an operative lifetime consistent with the time of the diagnostic inspection of the gastric district, assumed to be no more than 30 minutes. The capsule can be easily remotely controlled by the endoscopist using a joystick together with a purposely developed graphical user interface. The capsule design, prototyping, in vitro, ex vivo and preliminary in vivo tests are described in this work.

A Novel Magnetic Actuation System for Miniature Swimming Robots

A novel mechanism for actuating a miniature swimming robot is described, modeled, and experimentally validated. Underwater propulsion is obtained through the interaction of mobile internal permanent magnets that move a number of polymeric flaps arranged around the body of the robot. Due to the flexibility of the proposed swimming mechanism, a different range of performances can be obtained by varying the design features. A simple multiphysics dynamic model was developed in order to predict basic behavior in fluids for different structural parameters of the robot. In order to experimentally verify the proposed mechanism and to validate the model, a prototype of the swimming robot was fabricated. The device is 35 mm in length and 18 mm in width and thickness, and the forward motion is provided by four flaps with an active length of 20 mm. The model was able to correctly predict flap dynamics, thrust, and energy expenditure for magnetic dragging within a spindle-frequency range going from 2 to 5 Hz. Additionally, the model was used to infer robot-thrust variation related to different spindle frequencies and a 25% increase in flap active length. Concerning swimming performance, the proposed technical implementation of the concept was able to achieve 37 mm/s with 4.9% magnetic mechanism efficiency.

An Integrated System for Wireless Capsule Endoscopy in a Liquid-Distended Stomach

The design and development of a functional integrated system for gastroscopy is reported in this paper. The device takes advantage of four propellers enabling locomotion in a liquid environment and generating a maximum propulsive force of 25.5 mN. The capsule has been equipped with a miniaturized wireless vision system that acquires images with a frame rate of 30 fps (frames per second). The overall size of the capsule is 32 mm in length and 22 mm in diameter, with the possibility of decreasing the diameter to swallowable dimensions. The capsule is remotely controlled by the user who can intuitively drive the device by looking at the video streaming on the graphical interface. The average speed of the device is 1.5 cm/s that allows for a fine control of the capsule motion as demonstrated in experimental tasks consisting of passing through circular targets. The video system performances have been characterized by evaluating the contrast, the focus, and the capability of acquiring and perceiving different colors. The usability of the device has been tested on bench and on explanted tissues by three users in real time target-identification tasks, in order to assess the success of the integration process. The lifetime of the capsule with active motors and vision system is 13 min, that is, a timeframe consistent with traditional gastroscopic examinations.

Design of miniature modular in vivo robots for dedicated tasks in Minimally Invasive Surgery

Minimally Invasive Surgery (MIS) is widespread in medical procedures aiming to provide incision-less surgery. Conventional MIS provides limited tissue manipulation, because of the constrained directionality of force application and low number of Degrees of Freedom (DoFs). Robotic systems have been proposed to overcome the limitation of this approach, but still require the same number of incisions as in traditional MIS. Thus, new approaches such as minilaparoscopy, Single Incision Laparoscopic Surgery (SILS) and Natural Orifice Transluminal Endoscopic Surgery (NOTES) have been introduced. In a prospective complete intracavitary approach, the employment of a set of robotic units capable of dedicated tasks is supposed to overcome present drawbacks in terms of dexterity, number of DoFs and triangulation. The modular in vivo robots designed have a diameter of 12 mm, already compatible with most access ports, taking multiple DoFs completely inside the patient. These robotic units have a convenient workspace for the dedicated tasks of image acquisition, retraction and manipulation, while keeping a modular structure with minimal differences between the robotic units. Specifically, three robotic units were designed: a two DoFs camera robot, a two DoFs retraction robot, and a six DoFs manipulator robot. This article illustrates the modular design of the three robotic units, the manufacturing of two modules, and the successful assembly and testing of the camera robot.

Array of Robots Augmenting the Kinematics of Endocavitary Surgery

Minimally invasive surgery (MIS) has been introduced in the last decades with the goal of making scarless surgery feasible. In general, an MIS approach allows concrete benefits in terms of reduced trauma, quicker recovery times, and improved cosmetics. On the other hand, in its current state, MIS introduces more difficulties for surgeons, due to its intrinsic complexity. This issue has inspired the major technological challenge of designing miniaturized robots able to completely enter the body and to perform surgical procedures under intuitive teleoperation. The dream of achieving a completely minimally invasive therapeutic procedure, while offering the typical advantages of traditional open surgery, has brought to the complete elimination of external incisions by gaining access to the peritoneal cavity through a natural orifice. These scarless procedures are known as Natural Orifice Transluminal Endoscopic Surgery (NOTES) interventions. In this paper, novel approaches to NOTES instruments and platforms are presented, in which modular robots measuring 12 mm in diameter with basic functionalities (manipulation, cutting, vision, and retraction) and multiple degrees of freedom are deployed inside a human phantom and anchored on a supporting frame for the stable execution of tasks. This paper illustrates the general concept, novel design guidelines for the modular robots, and two robotic units successfully assembled and tested with ten users, in order to assess the capabilities of the system in pick and place experiments and cutting tasks. Experiments for the assessing force and accuracy are described as well.

A modular magnetic platform for natural orifice transluminal endoscopic surgery

Modern surgery is currently developing NOTES (Natural Orifice Translumenal Endoscopic Surgery) robotic approaches to enable scarless surgical procedures. Despite of the variegated devices proposed, they still have several limitations. In this work, we propose a surgical platform composed of specialized modules, in order to provide the overall system with adequate stability, dexterity and force generation. The concept behind the platform, the main modules and their performance are described to highlight the system potential to outperform current NOTES procedures.

Design of an autonomous swimming miniature robot based on a novel concept of magnetic actuation

In this work, we propose a new concept for locomotion of a miniature jellyfish-like robot based on the interaction of mobile permanent magnets. The robot is 35 mm in length and 15 mm in width, and it incorporates a rotary actuator, a magnetic rotor, several elastic magnetic tails and a polymeric body embedding a wireless microcontroller and power supply. The novel magnetic mechanism is very versatile for numerous applications and can be tailored and adapted on the basis of different specifications. An analytical model of the magnetic mechanism allows to shape the robot design based on the specific application. The working principle of the robot together with the design, prototyping and testing phases are illustrated in this paper.

A Miniature Robot for Retraction Tasks under Vision Assistance in Minimally Invasive Surgery

Minimally Invasive Surgery (MIS) is one of the main aims of modern medicine. It enables surgery to be performed with a lower number and severity of incisions. Medical robots have been developed worldwide to offer a robotic alternative to traditional medical procedures. New approaches aimed at a substantial decrease of visible scars have been explored, such as Natural Orifice Transluminal Endoscopic Surgery (NOTES). Simple surgical tasks such as the retraction of an organ can be a challenge when performed from narrow access ports. For this reason, there is a continuous need to develop new robotic tools for performing dedicated tasks. This article illustrates the design and testing of a new robotic tool for retraction tasks under vision assistance for NOTES. The retraction robots integrate brushless motors to enable additional degrees of freedom to that provided by magnetic anchoring, thus improving the dexterity of the overall platform. The retraction robot can be easily controlled to reach the target organ and apply a retraction force of up to 1.53 N. Additional degrees of freedom can be used for smooth manipulation and grasping of the organ.