By Shriya Manwani
A surgical robot can be described as ‘a powered computer controlled manipulator with artificial sensing that can be reprogrammed to move and position tools to carry out a range of surgical tasks’. Arguably, this definition suggests a surgical robot has functional similarity to a surgeon. However, the externally powered computer controlled mechanism with reprogrammable motions distinguishes the robot from both computer assisted surgery (CAS) and a surgeon. Thus, such robots do not replace a surgeon, but merely assist the surgeon under their supervision by carrying out minimally invasive surgical procedures autonomically.
They can carry out repetitive tasks for long periods, such as making small repetitive increments of motion for diathermy of a region, relieving the surgeon of a tiring task. The robot can also position tools very accurately for a long period of time, rigidly and without tremor, at a location defined by the surgeon or move them in micromotions or through a predefined, reprogrammable complex three-dimensional path.
The main difference between robot-assisted surgery and CAS is that robots are powered by a motorised system while CAS are manually moved by a surgeon using a console. Thus, even though the benefits of robot-assisted surgery also apply to CAS, robotic-surgery provides greater accuracy and precision than CAS. This is because they can be programmed to prevent motions into critical regions or only allow motions along specified direction, whilst in CAS the surgeon holds the tools and could mistakenly make incisions in unsafe regions. Thus, provided the robot itself is considered to be risk-free, robots can enhance the safety of the procedure compared with conventional surgery and to CAS.
The history of robotics in surgery began in 1985 with the Puma 560 robotic surgical arm used by Kwoh et al to perform neurosurgical biopsies. It was used as a standard industrial robot locked in place next to the patient’s head for the surgeon to use a fixture to orientate drills and biopsy probes, which were inserted into the skull manually by the surgeon, in order to locate a biopsy tool for neurosurgery. Puma 560 had the role of a traditional stereotactic frame in neurosurgery – it simply guided the surgeon to the exact location of the lesion to facilitate an accurate pathway through the brain, in order to safely remove as much abnormal tissue as possible while leaving healthy brain tissue fairly intact.
The Da Vinci Surgical System introduced in 2000 broke new ground by becoming the first robotic surgery system approved by the FDA for general laparoscopic surgery. The aspect that differentiated this system from its predecessors was its all-encompassing system of surgical instruments and camera/scopic tools, whereas its predecessors relied upon endoscopes and surgical assistants to perform surgery. The Da Vinci Surgical System provides a three-dimensional 10x magnification screen of the operative domain, allowing the surgeon to view the operative area with clarity and accuracy considerably superior to the laparoscopic technique. Its one-centimeter diameter surgical arms are a significant advancement compared to the large-armed systems in Puma 560. These reduced operating arms remove the need to leverage the sides of the incision walls hence there’s less contact between the exposed interior tissue and the surgical equipment, greatly reducing the risk of infection. It has EndoWrist technology which provides free movement in 7 axes, unlike the 4 axes provided by conventional laparoscopy tools, and rotation of almost 360º, replicating the exact movements of the surgeon controlling it and improving the accuracy in small operating spaces.
Since the first surgical robot was produced, several other robotic systems have been commercially developed and approved by the FDA for general surgical use. These include Prodoc, ROBODOC, the AESOP system and the comprehensive surgical robotic systems, Da Vinci and Zeus.
Currently, the Da Vinci system has been approved for adult and pediatric robot-assisted surgery in urological, general laparoscopic, general non-cardiovascular thoracoscopic and thoracoscopically-assisted cardiotomy surgeries.
The success rates of robot-assisted pyeloplasty have shown to be excellent, ranging between 94% and 100%. Further analysis found no differences between the open and the minimally invasive approach, both robotic and conventional, in terms of success and complication rates. However, some centres have reported higher complication rates and lower success rates than expected for ureteric reimplantation procedures compared to those previously obtained with open procedures.
The advantages of robot-assisted surgery are plentiful, as it overcomes the limitations of laparoscopic technologies and expands the benefits of minimally invasive surgery, making surgeries that were previously difficult or unfeasible, now possible.
Although every case is unique, the general recovery time following robotic surgery can be as little as two to three weeks. In contrast, conventional surgery may require several days of hospitalization and several months of recovery due to the larger incisions made compared to robot-assisted surgery.
Inherent in current laparoscopic equipment is a loss of natural hand-eye coordination, ergonomic position, dexterity and clear visualization. Surgical robots overcome these limitations and make more delicate dissections and anastomoses easier to perform. Observing the procedure using laparoscopic instruments through a 2-dimensional monitor is counterintuitive, as the surgeon must move the instrument in the opposite direction from the site of interest on the monitor to interact with the desired target. Robotic surgery restores proper hand-eye coordination and eliminates the fulcrum effect, making instrument manipulation more intuitive. The surgeon would be at an ergonomically designed workstation, allowing full range of motion and eliminating the need to twist and turn in uncomfortable positions to move the instruments. These systems are also designed so that the surgeons’ physiologic tremors are eliminated on the end-effector motion through hardware and software filters. They also have systems which scale movements so that large movements of the control grips are transformed into micromotions in the patient.
Robotic equipment also has enhanced vision due to its 3-dimensional view with depth perception that, combined with the increased degrees of freedom and improved dexterity, greatly improves the surgeon’s ability to dissect anatomic structures and construct microanastomoses.
However, there are also some limitations to these systems. Firstly, some patients may be concerned about the idea of a robot performing surgery on them and have the impression that the robot is making the decisions instead of a human, hence some patients might not consent robot-assisted surgery.
Robots are unable to process qualitative information thus they can’t adapt to a situation and integrate extensive and diverse information, and the absence of haptic sensation makes tissue manipulation heavily dependent on visualization. Additionally, almost no long-term follow up studies have been conducted to date so long-term data of success rates is scarce, thus, the overall efficacy of robot-assisted surgery is unknown.
With a price tag of a million dollars, a major disadvantage of surgical robots is their cost. Whether the price will fall or rise is still a matter of debate. Some believe that with improvements in technology and increasing experience in robotic surgery, the price will fall. Others believe that improvements in technology, such as haptics, increased processor speeds, and more complex hardware and software will increase the cost of these systems.
Another important disadvantage is the size of surgical robots. In today’s already crowded operating rooms, the large and bulky robotic arms pose a problem when attempting to also fit a surgical team and all the instruments in the same room. A potential solution could be to miniaturize the robotic arms or use larger operating rooms to accommodate the extra space requirements. In any case, both add to the cost of robot-assisted surgery.
Undoubtedly, the future of robotic surgery is bright. The technology is still in its early stages and its possible applications are as broad as minimally invasive surgery, since this technology is at the cutting edge of precision and miniaturization in the realm of surgery. Although most of the aforementioned disadvantages may be resolved with time and improvements in technology, if the costs remain high it is unlikely that there will be a robot in every operating room and thus unlikely that robotic surgery will be used for routine surgeries.
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