A Novel Snake Robot for NOTES

Michael M Awad, MD PhD, Shyam Thakkar, MD, Howie Choset, PhD. Washington University in St. Louis, Drexel University, Carnegie Mellon University


The emergence of laparoendoscopic technology has revolutionized the practice of surgery over the last 20 years. However, many complex procedures are still performed in an open fashion because of limitations of this technology. Furthermore, natural orifice translumenal endoscopic surgery (NOTES) remains out of reach of most clinicians because of a lack of facilitative tools. Robotics promises to usher in a new era of advanced minimally invasive techniques. An ideal robotic system is one that would allow for multi-quadrant access, a stable platform, small profile, while all along providing optimal visualization and appropriate dexterity. Here we describe the development of a novel snake-like robot that meets all of these criteria. First developed for minimally invasive cardiac surgery, the MICS robot was used in this pilot study to successfully perform a NOTES transrectal distal pancreatectomy in a porcine model.


We have developed several versions of snake robots – highly articulated devices that can use their many internal degrees of freedom to navigate tightly packed spaces. Initially designed for search and rescue operations in collapsed buildings, we recently developed a snake robot for minimally invasive cardiac surgery (MICS). The MICS robots can be viewed as a teleoperated probe consisting of a series of links that can both drive in intercavitary spaces and assume the shape of its surroundings. A key feature of the probe, unlike all other comparable robots, is that it uses conventional actuation technology which ensures its reliability and robustness. Furthermore, the links of the probe can be made out of almost any material, including plastic, allowing it to be ‘disposable’. There are three working channels allowing for passage of two working instruments and an endoscope through the probe.


To date, the MICS robot has been tested in 30 pigs, two cadavers and three cardiac ablation patients. In the current study, we used the MICS robot to perform a NOTES transrectal distal pancreatectomy. With the animal in prone position, a rectotomy was performed through which an overtube was inserted. A retroperitoneal dissection was performed to gain access to the distal pancreas with the robotic probe. Two 5mm abdominal ports were also used – one for laparoscopic monitoring and another for retraction when necessary. The distal pancreatectomy was performed using endoscopic biopsy forceps and needle knife cautery. The specimen was retrieved transrectally through the use of an endoscopic snare. The total procedure time was 118 minutes.


The MICS robot was able to perform a successful complex NOTES procedure with only minimal laparoscopic retraction assistance. The right upper, left upper and left lower quadrants were all easily visualized and accessible throughout the procedure. The benefits of the current platform over other laparoscopic and robotic systems include the stability of the system, its low profile, multi-quadrant accessibility, and the need for only a 12mm enterotomy or incision. Enhancements to optics and instrumentation will help to further increase the usability of the platform. Future indications may include transgastric NOTES approaches, endoluminal procedures and single port applications.

Session: Emerging Technology
Program Number: ET009

« Return to SAGES 2011 abstract archive