In Study, Robot Outperforms Standard Surgery Techniques

Live pigs and porcine tissue were used in the procedures

Supervised, autonomous robotic soft tissue surgery on a live subject in an open surgical setting is feasible and outperforms standard clinical techniques in a dynamic clinical environment, a new study shows.

The study, involving surgeons and scientists from Sheikh Zayed Institute for Pediatric Surgical Innovation at Children's National Health System, was published May 4 in Science Translational Medicine. It reports the results of soft tissue surgeries conducted on both inanimate porcine tissue and living pigs using proprietary robotic surgical technology, Smart Tissue Autonomous Robot (STAR), developed at Children's National. This technology removes the surgeon's hands from the procedure, instead utilizing the surgeon as supervisor, with soft tissue suturing autonomously planned and performed by the STAR robotic system.

Soft tissues connect, support or surround other structures and organs of the body; they include tendons, ligaments, fascia, skin, fibrous tissues, fat, synovial membranes, muscles, nerves, and blood vessels. More than 44.5 million soft tissue surgeries are performed in the U.S. each year.

"Our results demonstrate the potential for autonomous robots to improve the efficacy, consistency, functional outcome, and accessibility of surgical techniques," said Dr. Peter C. Kim, Vice President and Associate Surgeon­in­Chief of the Sheikh Zayed Institute. "The intent of this demonstration is not to replace surgeons, but to expand human capacity and capability through enhanced vision, dexterity, and complementary machine intelligence for improved surgical outcomes."

While robot­assisted surgery (RAS) has increased in adoption in health care settings, the execution of soft tissue surgery has remained entirely manual, largely because the unpredictable, elastic, and plastic changes in soft tissues that occur during surgery require the surgeon to make constant adjustments.

To overcome this challenge, STAR uses a tracking system that integrates near infrared florescent (NIRF) markers and 3D plenoptic vision, which captures light field information to provide images of a scene in three dimensions. This enables accurate, uninhibited tracking of tissue motion and change throughout the surgical procedure. This tracking is combined with STAR’s intelligent algorithm that guides the surgical plan and autonomously makes adjustments to the plan in real time as tissue moves and other changes occur. The STAR system also employs force sensing, submillimeter positioning, and actuated surgical tools. It has a bedside lightweight robot arm extended with an articulated laparoscopic suturing tool for a combined eight degrees of freedom.

"Until now, autonomous robot surgery has been limited to applications with rigid anatomy, such as bone cutting, because they are more predictable," said Axel Krieger, PhD, technical lead for Smart Tools at the Sheikh Zayed Institute. "By using novel tissue tracking and applied force measurement, coupled with suture automation software, our robotic system can detect arbitrary tissue motions in real time and automatically adjust."

To compare the effectiveness of STAR to other surgical procedures, the study included two surgeries performed on inanimate porcine tissue, linear suturing and an end­to­end intestinal anastomosis, which involves connecting the tubular loops of the intestine. The results of each surgery were compared with the same surgical procedure conducted manually by an experienced surgeon, by laparoscopy, and by RAS with the daVinci Surgical System. Intestinal anastomosis was the surgical procedure conducted on the living subjects in the study.

The Children's National research team conducted four anastomosis surgeries on living pigs using STAR technology; all subjects survived with no complications. The study compared these results to the same procedure conducted manually by an experienced surgeon using standard surgical tools.

All surgeries were compared based on the metrics of anastomosis, including the consistency of suturing based on average suture spacing, the pressure at which the anastomosis leaked, the number of mistakes that required removing the needle from the tissue, completion time, and lumen reduction, which measures any constriction in the size of the tubular opening. The comparison showed that supervised autonomous robotic procedures using STAR proved superior to surgery performed by experienced surgeons and RAS techniques.

Source: Children’s National Health System; May 4, 2016.