Servo - September 2016

Robotic Surgery Goes Soft

Robot-assisted surgery (RAS) has been around a long time, but it’s worth noting that “robot-assisted” is not synonymous with “autonomous.” For example, when using the renowned da Vinci system, a human surgeon is in control 100 percent of the time. Because soft tissue tends to move around in unpredictable ways, autonomous surgery has been applicable only to rigid anatomical items such as bones. However, surgeons and scientists from the Sheikh Zayed Institute for Pediatric Surgical Innovation — part of the Children's National Health System ( childrensnational.org) — have now demonstrated successful autonomous robotic soft tissue surgery via the Smart Tissue Autonomous Robot (STAR) — a system developed in-house.

Their research was actually performed on both dead and living pigs, but the technology should be suitable for humans as well. The study included two different surgeries: linear suturing and end-to-end intestinal anastomosis (i.e., connecting two tubular structures). Comparing the STAR surgery results with the same procedure conducted manually, by laparoscopy, and by RAS with the da Vinci system, it proved to be superior in terms of creating consistent suture spacing and withstanding higher leak pressures. (Obviously, leakage at suture points is highly undesirable.)

Mistakes requiring needle removal were minimal, as was constriction at the connection point. The drawback is that the surgery took 35 minutes, whereas manually controlled procedures took only eight minutes. This is still comparable to the average clinical procedures.

According to the Institute, some or all of the STAR technology could be brought into clinics within two years. The next step in the development cycle will be to further miniaturize the system’s tools and develop improved sensors to allow for wider use of the system.

The STAR soft tissue surgical system.

by Jeff and Jenn Eckert

Robytes

Origami with a Purpose

As we know, children have a strange desire to put things in their mouths that don’t belong there such as coins, marbles, bottle caps, and coat buttons. Among the most problematic items are the little button batteries found in calculators, watches, remote controls, and so forth. In fact, various sources confirm that as many as 6,000 children visit emergency rooms every year to be treated for battery ingestion — a shocking statistic (sorry). And it’s not just a choking issue. The battery current can react with saliva or stomach fluids, generate hydroxide, and cause caustic injuries to adjoining tissue. Serious damage can occur in less than two hours, and it can even create a hole in the esophagus.

To address the problem, researchers at MIT ( web.mit.edu), the University of Sheffield ( ww.sheffield.ac.uk), and the Tokyo Institute of Technology ( www.titech.ac.jp/english) have developed an ingestible origami robot that’s capable of capturing and removing these objects, thus eliminating the need for any surgery or endoscopy.

The device is folded and frozen into an ice capsule which dissolves when swallowed. The bot then unfolds and moves around as directed by external magnetic fields. An attached magnet grabs the battery, and the objects then continue through the digestive system. Propulsion occurs through a “stick-slip” motion in which the bot flexes to cause its appendages to either grip or slip free. As noted by one robotics professor, “This concept is both highly creative and highly practical, and it addresses a clinical need in an elegant way. It is one of the most convincing applications of origami robots that I For a demo, search “ingestible origami robot” on YouTube.