By Vinod K. Goel, PhD
Minimally invasive surgery has revolutionized the field of surgery. Like so many innovations, this advancement has been driven by deep, readily apparent needs: the need to treat patients with complications that might preclude open surgery; the need to reduce the unintended harms and side effects caused by open surgery; and the need to lower the cost and societal burden of treatment.
The achievements of minimally invasive technology and techniques have been fantastic, and in many ways, we have addressed the above needs. But ask any interventionalist, and you will quickly learn that there are still pain points—limitations—preventing minimally invasive surgery from realizing its full benefits. These are “second-generation” needs, which are created by the solution to the original needs.
Take, for example, the challenge an interventionalist faces when performing a keyhole surgery to repair a hernia. In conventional surgery, the operator has direct access to the anatomy. Having opened up the patient, the surgeon can see the whole of the structures being treated and the structures adjacent to them. Lesions are readily apparent and can be appreciated with touch and sight. In minimally invasive surgery, the interventionalist of course does not have these abilities. Endoscopy yields images from unnatural positions with unintuitive scale. Though these images may be familiar to Ms. Frizzle’s students in The Magic School Bus, they’re not much like what a medical student sees in an anatomy lab. Images produced by ultrasound, x-ray, or magnetic resonance modalities are sometimes even less intuitive.
Accompanying the challenge of visualization is the challenge of control. In an open surgery, with diseased and healthy tissues alike exposed, a surgeon can directly apply precision instruments to the task at hand. Tactile feedback is naturally present and is an essential source of information throughout the procedure. Minimally invasive instruments generally cannot provide this intuitive feedback. Their range of motion is limited by their very nature, and controlling actuators at the distal tip of a device that may be feet away from the controls is never as intuitive as direct use of a rigid open tool. Perhaps paradoxically, the tools often technically allow for a great deal of precision; minimally invasive technology today can transform large input motions into very small outputs at the ends of effectors. But there remains a need for intuitiveness to pair with this precision.
We also know that the imaging used for many minimally invasive procedures can be damaging. The ionizing radiation used in x-ray angiography has effects that cannot be ignored. Acute effects are visible after complex endovascular interventions; patients might look as if they’ve spent too much time on the beach without sunscreen. Yet unlike UV rays, which generally do not penetrate deeper than the skin, the radiation damage done by x-rays runs in and out through the body—and also presents a quantifiable cancer risk to caregivers who are regularly exposed, according to studies. At the same time, chemical agents used to enhance imaging are often dangerous themselves; for example, fluoroscopy typically relies on iodinated compounds, which are toxic to the kidneys.
These challenges are new. Before minimally invasive surgery, there was no real risk that a patient’s kidneys might be damaged by a carotid surgery. There was less concern that a surgeon going in to repair a hernia might miss an unintended bowel nick. There was no patient selection problem in which the operator would worry about the forceps’ limited degrees of freedom. So even as minimally invasive surgery has addressed the problems of the past, it has created new ones that we now must solve in our quest for the best possible patient care.
Lest I should seem pessimistic, I’ll point out that the path to resolving these limitations is clear. The pace of innovation in medical technologies and interventional techniques is faster than ever, and we are already reaping its benefits. In fact, I believe the technologies that will solve these new problems—that will propel minimally invasive surgery to its ultimate potential—are already on the market, although we have only scratched the surface of what they can do. The three key technologies to watch are enhanced imaging, big data, and robotics.
New alternative imaging and image guidance technologies will help overcome many of today’s imaging limitations. As these innovations develop, computation will start to bridge the gap between unnatural imaging and the operator’s intuitive visual perception. While radiographic and ultrasound imaging yield images that can be difficult to interpret, we are seeing the advent of computerized systems that use image processing algorithms and machine learning to do much of the heavy lifting of interpretation. This will free the clinician to focus more on the patient and the procedure at hand and facilitate improved outcomes. At the same time, we will see continued development of image guidance technologies that leverage preoperative imaging or interactive anatomical mapping to provide improved guidance over conventional imaging and reduced dependence on radiation and toxic chemicals.
Big data and digital healthcare also stand to bridge the intuition gap involved in minimally invasive surgery. Presently, an interventionalist’s skill is highly dependent on case volume—on the amount of case data stored in his or her brain. Today, we are starting to see a growing ability to electronically model this type of learning, to build artificial intelligence systems that can make use of data from more cases and encounters than any individual clinician has seen. Based on this data, clinicians will have access to guidance and predictive capabilities that significantly augment their intuition and natural ability.
Imaging and digital health advances will make their biggest impact when combined with robotics, laying the path for computer-assisted surgery and even autonomous surgery. Advances in robotic surgery are already improving the cost and performance of these systems. We are starting to see effective haptic feedback technology to enhance control. In the future, data and imaging will allow robotic systems to autonomously perform many surgical tasks—a form of “autopilot” that would permit the clinician to concentrate on the most demanding parts of an intervention.
The imminent convergence of these technologies will be a turning point in health tech development. Computation, storage, and connectivity are poised to transform minimally invasive surgery—making open surgery more and more rare, minimizing avoidable harm, and providing therapies to every patient in need.
Vinod K. Goel, PhD, is president of Centerline Biomedical, Inc. Centerline is developing next-generation imaging and real-time 3D navigation to empower physicians with solutions designed to improve outcomes, lower costs, simplify complex procedures, and reduce radiation exposure to patients, clinicians, and caregivers in minimally invasive endovascular procedures. Founded in 2014 as a spinoff of Cleveland Clinic, Centerline is changing the way healthcare is delivered.