Magnetic air capsule robotic system: proof of concept of a novel approach for painless colonoscopy.

BACKGROUND: Despite being considered the most effective method for colorectal cancer diagnosis, colonoscopy take-up as a mass-screening procedure is limited mainly due to invasiveness, patient discomfort, fear of pain, and the need for sedation. In an effort to mitigate some of the disadvantages associated with colonoscopy, this work provides a preliminary assessment of a novel endoscopic device consisting in a softly tethered capsule for painless colonoscopy under robotic magnetic steering. METHODS: The proposed platform consists of the endoscopic device, a robotic unit, and a control box. In contrast to the traditional insertion method (i.e., pushing from behind), a "front-wheel" propulsion approach is proposed. A compliant tether connecting the device to an external box is used to provide insufflation, passing a flexible operative tool, enabling lens cleaning, and operating the vision module. To assess the diagnostic and treatment ability of the platform, 12 users were asked to find and remove artificially implanted beads as polyp surrogates in an ex vivo model. In vivo testing consisted of a qualitative study of the platform in pigs, focusing on active locomotion, diagnostic and therapeutic capabilities, safety, and usability. RESULTS: The mean percentage of beads identified by each user during ex vivo trials was 85 ± 11%. All the identified beads were removed successfully using the polypectomy loop. The mean completion time for accomplishing the entire procedure was 678 ± 179 s. No immediate mucosal damage, acute complications such as perforation, or delayed adverse consequences were observed following application of the proposed method in vivo. CONCLUSIONS: Use of the proposed platform in ex vivo and preliminary animal studies indicates that it is safe and operates effectively in a manner similar to a standard colonoscope. These studies served to demonstrate the platform's added advantages of reduced size, front-wheel drive strategy, and robotic control over locomotion and orientation.

Mucoadhesive film for anchoring assistive surgical instruments in endoscopic surgery: in vivo assessment of deployment and attachment.

BACKGROUND: Flexible endoscopic procedures in the gastric cavity are usually performed by operative instruments introduced through the working channels of a gastroscope. To enable additional functions and to widen the spectrum of possible surgical procedures, assistive internal surgical instruments (AISI) may be deployed through the esophagus and fixed onto the gastric wall for the entire duration of the procedure. This paper presents a solution for deploying, positioning, and anchoring AISI inside the stomach by exploiting a chemical approach. METHODS: A mucoadhesive polymer was synthesized and tested inside the stomach. In vivo trials were performed on a porcine model by introducing the AISI provided with mucoadhesive by means of an overtube through the mouth. Targeted deployment was achieved by a purposely developed delivery device, passed through the operative channel of a gastroscope. The total time for deployment, positioning, and anchoring of the AISI was evaluated by testing the procedure with passive modules (10, 12, 15, 20 mm in diameter) and active devices: e.g., a miniaturized wired camera and a wireless illumination module. The time and force required for the detachment of the modules were measured. RESULTS: The whole procedure of in vivo deployment, positioning, and attachment of an AISI was performed in approximately 6 min. A preload force of 5 N for 3 min was required for anchoring the modules. The stable adhesion was maintained for a maximum of 110 min. Thanks to the positioning of the camera in the fundus, a wide view of the gastric cavity was obtained. The force required to detach the modules reached 2.8 N. CONCLUSIONS: Mucoadhesive anchoring represents a completely biocompatible and safe solution for stable positioning of AISI onto mucosal tissue. This novel polymeric mechanism can be useful for designing intraluminal accessories and tools that enhance surgeons' performances in endoluminal procedures.

Robotic versus manual control in magnetic steering of an endoscopic capsule.

BACKGROUND AND STUDY AIMS: Capsular endoscopy holds promise for the improved inspection of the gastrointestinal tract. However, this technique is limited by a lack of controlled capsule locomotion. Magnetic steering has been proposed by the main worldwide suppliers of commercial capsular endoscopes and by several research groups. The present study evaluates and discusses how robotics may improve diagnostic outcomes compared with manual magnetic steering of an endoscopic capsule. MATERIALS AND METHODS: An endoscopic capsule prototype incorporating permanent magnets was deployed in an ex vivo colon segment. An operator controlled the external driving magnet manually or with robotic assistance. The capsule was maneuvered through the colon, visualizing and contacting targets installed on the colon wall. Procedure completion time and number of targets reached were collected for each trial to quantitatively compare manual versus robotic magnetic steering ( T-test analysis with P = 0.01). Then, through a set of in vivo animal trials, the efficacy of both approaches was qualitatively assessed. RESULTS: In ex vivo conditions, robotic-assisted control was superior to manual control in terms of targets reached (87 % +/- 13 % vs 37 % +/- 14 %). Manual steering demonstrated faster trial completion time (201 +/- 24 seconds vs 423 +/- 48 seconds). Under in vivo conditions, the robotic approach confirmed higher precision of movement and better reliability compared with manual control. CONCLUSIONS: Robotic control for magnetic steering of a capsular endoscope was demonstrated to be more precise and reliable than manual operation. Validation of the proposed robotic system paves the way for automation of capsular endoscopy and advanced endoscopic techniques.

A magnetic internal mechanism for precise orientation of the camera in wireless endoluminal applications.

BACKGROUND AND STUDY AIMS: The use of magnetic fields to control operative devices has been recently described in endoluminal and transluminal surgical applications. The exponential decrease of magnetic field strength with distance has major implications for precision of the remote control. We aimed to assess the feasibility and functionality of a novel wireless miniaturized mechanism, based on magnetic forces, for precise orientation of the camera. MATERIALS AND METHODS: A remotely controllable endoscopic capsule was developed as proof of concept. Two intracapsular moveable permanent magnets allow fine positioning, and an externally applied magnetic field permits gross movement and stabilization. Performance was assessed in ex vivo and in vivo bench tests, using porcine upper and lower gastrointestinal tracts. RESULTS: Fine control of capsule navigation and rotation was achieved in all tests with an external magnet held steadily about 15 cm from the capsule. The camera could be rotated in steps of 1.8 degrees . This was confirmed by ex vivo tests; the mechanism could adjust the capsule view at 40 different locations in a gastrointestinal tract phantom model. Full 360 degrees viewing was possible in the gastric cavity, while the maximal steering in the colon was 45 degrees in total. In vivo, a similar performance was verified, where the mechanism was successfully operated every 5 cm for 40 cm in the colon, visually sweeping from side to side of the lumen; 360 degrees views were obtained in the gastric fundus and body, while antrally the luminal walls prevented full rotation. CONCLUSIONS: We report the feasibility and effectiveness of the combined use of external static magnetic fields and internal actuation to move small permanent intracapsular magnets to achieve wirelessly controllable and precise camera steering. The concept is applicable to capsule endoscopy as to other instrumentation for laparoscopic, endoluminal, or transluminal procedures.

Wireless therapeutic endoscopic capsule: in vivo experiment.

BACKGROUND AND STUDY AIM: Capsule endoscopy is becoming well established as a diagnostic technique for the gastrointestinal tract. Nevertheless swallowable capsule devices that can effectively perform surgical and therapeutic interventions have not yet been developed. Such devices would also be a valuable support for natural orifice transluminal endoscopic surgery (NOTES). The objective of this study was to assess the feasibility of using a swallowable wireless capsule to deploy a surgical clip under remote control. MATERIALS AND METHODS: A wireless endoscopic capsule, diameter 12.8 mm and length 33.5 mm, was developed. The device is equipped with four permanent magnets, thus enabling active external magnetic steering. A nitinol clip is loaded on the topside of the capsule, ready to be released when a control command is issued by an external operator. Repeated ex vivo trials were done to test the full functionality of the therapeutic capsule in terms of efficiency in releasing the clip and reliability of the remote control. An in vivo test was then carried out in a pig: the capsule was inserted transanally and steered by means of an external magnetic arm towards an iatrogenic bleeding lesion. The clip, mounted on the tip of the capsule, was released in response to a remote signal. The procedure was observed by means of a flexible endoscope. RESULTS: A wireless capsule clip-releasing mechanism was developed and tested. During ex vivo trials, the capsule was inserted into the sigmoid section of a phantom model and steered by means of the external magnet to a specific target, identified by a surgical suture at a distance of 3 cm before the left flexure. The capsule took 3 to 4 minutes to reach the desired location moving under external magnetic guidance, while positioning of the capsule directly on the target took 2 to 3 minutes. Successful in vivo clipping of an iatrogenic bleed by means of a wireless capsule was demonstrated. CONCLUSIONS: This study reports the first successful in vivo surgical experiment using a wireless endoscopic capsule, paving the way to a new generation of capsule devices able to perform both diagnostic and therapeutic tasks.

Dual-Continuum Design Approach for Intuitive and Low-Cost Upper Gastrointestinal Endoscopy.

OBJECTIVE: This paper introduces a methodology to design intuitive, low-cost, and portable devices for visual inspection of the upper gastrointestinal tract. METHODS: The proposed approach mechanically couples a multi-backbone continuum structure, as the user interface, and a parallel bellows actuator, as the endoscopic tip. Analytical modeling techniques derived from continuum robotics were adopted to describe the endoscopic tip motion from user input, accounting for variations in component size and pneumatic compressibility. The modeling framework was used to improve intuitiveness of user-to-task mapping. This was assessed against a 1:1 target, while ease-of-use was validated using landmark identification tasks performed in a stomach simulator by one expert and ten non-expert users; benchmarked against conventional flexible endoscopy. Pre-clinical validation consisted of comparative trials in in-vivo porcine and human cadaver models. RESULTS: Target mapping was achieved with an average error of 5° in bending angle. Simulated endoscopies were performed by an expert user successfully, within a time comparable to conventional endoscopy (<1 minute difference). Non-experts using the proposed device achieved visualization of the stomach in a shorter time (9s faster on average) than with a conventional endoscope. The estimated cost is <10 USD and <30 USD for disposable and reusable parts, respectively. Significance and Conclusions: Flexible endoscopes are complex and expensive devices, actuated via non-intuitive cable-driven mechanisms. They frequently break, requiring costly repair, and necessitate a dedicated reprocessing facility to prevent cross contamination. The proposed solution is portable, inexpensive, and easy to use, thus lending itself to disposable use by personnel without formal training in flexible endoscopy.

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.

Wireless steering mechanism with magnetic actuation for an endoscopic capsule.

This paper illustrates the design, development and testing of a miniature mechanism to be integrated in endoscopic capsules for precise steering capabilities (Magnetic Internal Mechanism, MIM). The mechanism consists of an electromagnetic motor connected to a couple of small permanent magnets and immersed in a static magnetic field produced by an external permanent magnet or a by an electromagnetic coil. The overall steering capsule, integrating the magnetic steering mechanism and the vision system is 15.6 mm in diameter, 48 mm in length, 14.4 g in weight and can be oriented with an accuracy of 0.01 degrees . As regards system scalability, the capsule size could be reduced down to 11 mm in diameter by optimizing some mechanical components. On the other hand, the magnets size cannot be reduced because the magnetic link between internal and external magnets at typical operation distances (about 15 mm) would be weak.

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.