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.

References

• 1 Reavis K M, Scott Melvin W. Advanced endoscopic technologies.  Surg Endosc. 2008;  22 1533-1546
• 2 Menciassi A, Quirini M, Dario P. Microrobotics for future gastrointestinal endoscopy.  Minimally Inv Ther Allied Technol. 2007;  16 91-100
• 3 Lehman A C, Rentschler M E, Farritor S M, Oleynikov D. The current state of miniature in vivo laparoscopic robotics.  J Robotic Surg. 2007;  1 45-49
• 4 Lehman A C, Berg K A, Dumpert J. et al . Surgery with cooperative robots.  Comput Aid Surg. 2008;  13 95-105
• 5 Quirini M, Menciassi A, Scapellato S. et al . Feasibility proof of a legged locomotion capsule for the GI tract.  Gastrointest Endosc. 2008;  67 1153-1158
• 6 Valdastri P, Menciassi A, Dario P. Transmission power requirements for novel ZigBee implants in the gastrointestinal tract.  IEEE Trans Biomed Eng. 2008;  55 1705-1710
• 7 Carpi F, Galbiati G, Carpi A. Controlled navigation of endoscopic capsules: Concept and preliminary experimental investigations.  IEEE Trans Biomed Eng. 2007;  54 2028-2036
• 8 Valdastri P, Quaglia C, Menciassi A. et al .Surgical clip releasing wireless capsule, European patent application 08 425 604.9. filed on 16/09/2008:
• 9 Kirschniak A, Kratt T, Stuker D. et al . A new endoscopic over-the-scope clip system for treatment of lesions and bleeding in the GI tract: first clinical experiences.  Gastrointest Endosc. 2007;  66 162-167
• 10 Schurr M O, Hartmann C, Ho C N. et al . An over-the-scope clip (OTSC) system for closure of iatrogenic colon perforations: results of an experimental survival study in pigs.  Endoscopy. 2008;  40 584-588
• 11 Raju G S, Gajula L. Endoclips for GI endoscopy.  Gastrointest Endosc. 2004;  59 267-279
• 12 Given Imaging Ltd. Website. http://www.givenimaging.com; Stand: 15 November 2008
• 13 Ramcharitar S, Patterson M S, van Geuns R J. et al . Technology insight: Magnetic navigation in coronary interventions.  Nat Clin Pract Cardiovasc Med. 2008;  5 148-156
• 14 Swain P. The future of wireless capsule endoscopy.  World J Gastroenterol. 2008;  14 4142-4145