Since its mainstream introduction in the 1980s, minimally invasive surgery (MIS) has been used for an ever increasing number of procedures. Regardless of the aim of the operation, surgeons are continually seeking to decrease incision size for better clinical and aesthetic outcomes. New miniature robotically assisted devices are now able to perform surgery directly from within the body.
Robotic minimally invasive surgery has limitations. The small entry site or use of a natural body orifice means not all surgical sites are accessible. Moreover, those that require the use of instruments mounted on long, flexible scopes offer poor ergonomics, are difficult to manipulate, may transmit tremor and, most importantly, do not give the surgeon haptic feedback. This means it is often difficult to feel the resistance in the tissues being manipulated and to know how much force to apply.
Three-D robotic views of the surgical site have improved to the point of “seeing better than the human eye,” according to Professor Law Wai-lun, Director of Surgical Skills Centre at Hong Kong University. But the lack of ergonomics and haptic feedback have been serious barriers to adoption. This led his department to follow the Western model of collaborating with robotics experts, giving engineers from the Hong Kong Polytechnic University their surgical wish list.
The Robotic Arms Inserted Inside the Body
The PolyTech University robotics team has a long history of working in the Chinese government space program. Their robots now can be controlled from earth while exploring the moon. Thus, working within the human body required “some downscaling in dimensions,” explained Law. However, the basics of haptic feedback were well understood and have been built into a prototype, the Novel Surgical Robotic System (NSRS), currently being tested in animals. The miniaturization of the robotic arms allows them to be inserted through a single incision or a natural orifice. They then unfold inside the body. The system has been designed to perform a variety of abdominal and pelvic procedures.
The miniaturization of the robotic arms allows them to be inserted through a single incision or a natural orifice.
The NSRS arms are controlled by specially designed micro-motors that are able to work without large external machinery to drive the tools. Additionally, they are placed next to the end-effectors for great precision. This also enables them to provide information about the resistance encountered.
“The arms have 10 degrees of freedom in movement which we are testing in different procedures. Several different prototypes have been created and redesigned over the past one to two years as the surgical teams test the robotics,” explained Law. “We have successfully performed a cholecystectomy on an anesthetized pig, but we still need to perform further operations on cadavers, as the organs are not in the same positions in humans and animals, before we can seek FDA approval and start the first in-human trials.” “Our aim,” he went on to explain, “is to have a low-cost system that is small and efficient, provides excellent haptic feedback and is ideal for a wide range of different abdominal surgeries.”
Virtual Incision’s Miniaturized Surgical Robot
This niche in the marketplace has been spotted by other manufacturers. Virtual Incision, based in Pleasanton, California, recently announced the successful first-in-human use of its miniaturized robotically assisted surgical device (RASD) for colon resection, a procedure performed to treat patients with lower gastrointestinal diseases.
The robotically assisted colon resection procedures were completed in Asunción, Paraguay, as part of the safety and feasibility trial for the technology. The surgeries were successful and the patients are recovering well. More than two million patients undergo colon resection procedures globally each year. Approximately two-thirds of these procedures are performed via a completely open surgical procedure involving a 20- to 30-centimeter incision and up to six weeks of recovery time.
Like the NSRS system, the Virtual Incision robot is small enough to position in the abdominal cavity via an umbilical incision. Only the handle and cables stay on top. It is quite compact and does not need a specialize operating room. Because of its much smaller size, it is expected to be significantly less expensive than existing robotic alternatives for laparoscopic surgery, according to Virtual Incision which is working toward FDA 510(k) clearance for the system in the United States.