Jeremy Warren, MD, an associate professor of surgery at the University of South Carolina School of Medicine, Greenville, checks PubMed frequently for new reports on robotic hernia repair.
Dr. Warren, a minimally invasive surgery fellowship-trained surgeon and proponent of the robot in hernia repair, has been tracking the literature on the robot for years. A search last December turned up 438 articles, with more than 100 published in the past year. That’s not a lot for a technology that has been around since the late 1990s, and one that grew in proportional use more than 40-fold for inguinal and ventral hernia repairs between 2012 and 2018 (JAMA Netw Open 2020;3[1]:e1918911).
The published literature does not reflect what Dr. Warren believes the robot can do. But, he said, the evidence “is coming.”
As it stands now, the state of published literature on robotic hernia repair is a hot-button issue: Some surgeons argue that more research is necessary before this expensive technology becomes more widely adopted, whereas others claim that the traditional system of presenting and publishing data—especially in the form of randomized controlled trials (RCTs)—is not designed to pick up the nuances offered by this technology.
Supporters of robotic surgery say the literature does not demonstrate the advantages they see in their practices. Conrad Ballecer, MD, a surgeon in Arizona and a vocal educator in robotic surgery, said, “For the overwhelming majority of surgeons who have incorporated robotics into their practice, they don’t need peer-reviewed publications to legitimize what they do.”
The debate on robotic hernia repair splinters along the private versus academic divide in surgery, Dr. Ballecer said. Scientific publications belong to the world of academia, but private practice surgeons are driving the robotic movement in hernia repair and have amassed some of the largest series in the world, he said. Most don’t publish their results or participate in trials, he added. Instead, they tend to share their experiences through training programs or on social media, which accelerates knowledge sharing compared with traditional publishing. Dr. Ballecer said these forums provide critical information about robotic hernia repair. “I don’t think it’s an obligation that surgeons publish. It’s our obligation to follow up our patients and track our own data,” he said. “At the end of the day, people are going to do what works in their practice.”
State of the Evidence
Most of the studies of robotic inguinal or ventral hernia repair are case series or retrospective comparative studies, along with some registry-based reports from the Abdominal Core Health Quality Collaborative (formerly the Americas Hernia Society Quality Collaborative). Three published reports from RCTs compare robotic and laparoscopic repairs. The multicenter RIVAL (Robotic Inguinal vs Transabdominal Laparoscopic Inguinal Hernia Repair) trial of inguinal hernia repair—in which Dr. Warren participated—compared a robotic approach with a transabdominal laparoscopic approach; the authors found showed no clinical benefit for patients and, contrary to expectations, no ergonomic advantages for the participating surgeons (JAMA Surg 2020;155[5]:380-387). The authors reported higher costs, longer operative time and additional surgeon frustration using the robotic approach.
A multicenter trial of 124 patients in Houston demonstrated that robotic ventral repairs increased operative duration and health care costs, but did not reduce 90-day postoperative hospital days (BMJ 2020;370:m2457). In addition, last October, surgeons from Cleveland Clinic reported results from the PROVE-IT randomized trial comparing the patient-reported outcomes of 75 patients who underwent robotic or laparoscopic ventral hernia repair (JAMA Surg [Epub Oct 21, 2020]. doi: 10.1001/jamasurg.2020.4569). Two surgeons performed all the repairs; both completed fellowships with training in advanced laparoscopy and complex abdominal wall reconstruction, and both had robotic training and credentialing in line with requirements from their department and Intuitive Surgical (the maker of the da Vinci system). One of the enrolling surgeons had several years of robotic experience and the other was in the first year of clinical practice.
They found the two approaches resulted in similar outcomes, with no differences in postoperative pain, complication rates, quality of life and hospital length of stay. The robotic approach increased the median operative time by 52 minutes, with robotic procedures taking a median of 146 minutes. This incurred additional cost, which the authors said was not offset by a measurable clinical benefit. They concluded that “the need for randomized trials evaluating these robotic techniques now grows more important than ever. … Owing to the increased operative time and associated cost, there is currently no measurable benefit to justify the robotic approach.”
Ajita Prabhu, MD, and Clayton C. Petro, MD, surgeons from Cleveland Clinic, led the PROVE-IT trial, and Dr. Prabhu also participated in the RIVAL trial. Dr. Prabhu said they expected the PROVE-IT trial to demonstrate that patients who underwent robotic repair experienced less pain; it did not. “It is true that we did not find a clinical benefit for the patient with one approach over the other,” she said. “However, this does not suffice to say that this is evidence of the absence of clinical benefit. We’re going to need a lot more data from surgeons from other centers with long-term follow-up.”
She added that although the study is small, there is value in publishing the experiences of two minimally invasive surgery–trained surgeons who compared the two approaches in a randomized fashion.
Drs. Prabhu and Petro also looked at the question of fixation of the mesh prosthesis in intraperitoneal onlay mesh procedures. The robotic platform makes it possible to do intracorporeal suturing and peritoneal mesh fixation with a running stitch. But the PROVE-IT study suggested patients did not have less pain if their mesh was sewn in place robotically instead of fixed with tacks and transfascial sutures laparoscopically.
In an invited commentary, surgeons Ann M. Defnet, MD, and S. Scott Davis Jr., MD, noted that it is “valuable to know that sewing the mesh may not adequately address the problem of postoperative pain.” They predicted the study would be criticized because the investigating surgeons were not expert robotic surgeons and called on “robotic protagonists to demonstrate the benefits with higher level evidence to support widespread adoption.”
Since then, other surgeons have taken issue with the authors’ conclusions. Yuri Novitsky, MD, the director of the Comprehensive Hernia Center at Columbia University, in New York City, said the PROVE-IT study had methodological flaws. The authors did not record the pain medications used by patients and did not collect pain data at a standardized point, he said. He added that at least one of the enrolling surgeons was still in their learning curve. He is concerned that the authors came to negative, sweeping conclusions about the robot and suggested this could have harmful consequences for other surgeons’ practices.
“The way this study is concluded, the way it’s designed, it may impede robotic access and utilization by those who have learned to rely on it,” Dr. Novitsky said. He said he worries that hospital administrators and insurance companies may be influenced by the study’s conclusions.
Robotic inguinal hernia repair and intraperitoneal mesh placement for ventral hernias are often regarded as techniques that surgeons should be comfortable with before moving to more advanced robotic techniques, the PROVE-IT authors said. However, if future studies fail to show a clinical benefit of the robot in advanced procedures, then use of the robot in more basic techniques becomes “a bridge to nowhere,” they wrote.
Sean Orenstein, MD, an associate professor of surgery at Oregon Health & Science University, in Portland, disagreed. He uses the robot in complex cases where he would struggle with regular laparoscopy, having first trained on the robot with simpler cases. “It is a bridge to somewhere, and an important bridge,” he said. “But how do you measure that in a study?”
The Role of RCTs in Assessing the Robot
It will be challenging to tease out the benefits of robotic repairs through small RCTs, said surgeons on both sides of the debate.
For inguinal hernia repair, patient outcomes tend to be good whether it is performed robotically or laparoscopically, so to discern a measurable difference would require large numbers of patients. For ventral hernia repairs, the issue is more complicated. For one, the robotic approach makes it easier for surgeons to transition from performing open repairs to minimally invasive surgery. The visualization is better, and it can be easier to identify specific tissue planes and manipulate tissue. “To me, it’s still laparoscopy but a heightened version of it,” Dr. Orenstein said.
The robot allows a surgeon to keep mesh out of the peritoneal cavity. For robotic transversus abdominis release or extended totally extraperitoneal repair, there isn’t necessarily a laparoscopic alternative. “If you’re someone who feels like it’s very important to get mesh out of the peritoneal cavity, then the robot is great because it allows you to do that,” Dr. Petro noted. “The trouble is that to elucidate that in a clinical trial isn’t necessarily practical. It takes years and years to come to fruition.”
Dr. Petro added that RCTs are excellent at answering a single specific question, but the results of one trial cannot be used to call for an end to robotic hernia repairs. “A negative conclusion doesn’t mean that a trial is anti-robot. It just means that the answer to one question did not favor the robot,” he said.
A randomized trial requires equipoise; investigators must believe that it’s ethical to randomly assign patients to either treatment arm. Surgeons who are more facile with one approach over the other feel it’s unfair to subject their patients to randomization. “I can’t ethically look at my patients and say, ‘I’m going do this procedure one way or the other; I don’t know which one is better,’ when I do know,” Dr. Novitsky said.
Many published studies of robotic surgery in hernia and other general surgery fields use operating time as an outcome. In many of these studies, robotic cases take longer, particularly when a surgeon is early in their learning curve. The added time in the OR is not always offset by shorter lengths of stay or clinical benefits. But operating times may be a misleading variable, given inherent differences in the techniques used and the experience of surgeons in the study, Dr. Warren said. “Operating times vary so much from surgeon to surgeon and practice to practice.”
Just because randomized trials are challenging does not mean they should not be done, Dr. Petro noted. “We’ve never accepted, in most realms of medicine, to just throw your hands in the air and say, ‘Well, I guess we’re just not going to critically evaluate these techniques.’ That’s not how it works,” he said, adding that if only experts do trials, the results may not be applicable to real-world practice.
Does Conflict of Interest Matter?
Surgeons who educate, lecture and publish about robotic repairs often do so with financial support from the industry. Dr. Warren said he believes surgeons who receive industry support are too often “dismissed out of hand” for working with industry. He receives funding from Intuitive Surgical, but feels it should not be used to undermine his publications if he is transparent about reporting it. “It can be insulting because I want to educate others, and the best way to do that is via industry-assisted tools. It doesn’t mean I’m not genuine in my evaluation of and use of the robot.”
Surgeons are not always forthcoming about industry support, even though it is required. In a 2018 analysis published in Annals of Surgery, investigators reported that the authors of robotic surgery studies did not consistently report payments from Intuitive Surgical in published articles, based on a comparison with the Open Payments database (Ann Surg 2018;268[1]:86-92). “As long as people are open about industry support, I think it’s fine. But they need to be open about it,” Dr. Petro said.
Industry support is critical for the development of new technologies and the training of surgeons, said Edward Felix, MD, a retired private practice surgeon in California. An early adopter of laparoscopy for hernia repair, he has become convinced of the robot’s value after initially criticizing the technology. Industry-supported training in robotic surgery has led to well-trained surgeons and prevented some of the errors of the laparoscopic era, he said. “In the early days of laparoscopy, there was no real mentoring and there were no restraints. That’s why I think it took 25 years for laparoscopic hernia repair to take off,” he said.
Dr. Orenstein said a paradigm shift has occurred in modern medicine, moving away from traditional publishing to more hands-on learning. Industry-sponsored courses are essential for developing advanced surgical skills for new techniques and technology. “They’re becoming more popular,” he said, acknowledging that there is a potential for bias because courses are industry sponsored. “But I think surgeons make a concerted effort to be up front and honest with our surgical education and teaching,” he said.
Surgeons Tracking Their Outcomes
Dr. Prabhu believes surgeons need to track, present and publish their experiences with new technology. If they don’t want to participate in RCTs, they should contribute to registries, which can help demonstrate where the robot has value, she said. She noted that sharing information on social media is not enough.
“I do think [contributing data] is part of your responsibility, particularly if that’s something that you want to keep offering to patients,” she said. “The best thing that we can do is educate ourselves as to what’s out there, critically appraise it and decide how to use it.”
Dr. Warren believes it is only a matter of time before the published literature reflects what surgeons claim the robot can do. He said as more surgeons gain experience with the robot and publish more results, the advantages will become evident.
However, that won’t occur without more data from surgeons about what is happening in their practices, Dr. Warren cautioned. “Those of us who are out there preaching the robotic technique and the benefits of this new approach, we have an obligation to review our results, talk about our results, track those results, and hopefully to publish those results,” he said.
Dr. Ballecer is a consultant for Intuitive Surgical and Medtronic. Dr. Felix receives speaking fees from Medtronic. Dr. Novitsky is a consultant and proctor for Intuitive Surgical; a consultant for BD Interventional; and has received grants from Intuitive Surgical. Dr. Orenstein is an instructor and consultant and serves on the advisory board of BD Bard; an instructor for Intuitive Surgical; an instructor and consultant for LifeCell/Allergan; and a consultant for Polynovo. Dr. Petro is the recipient of a 2020 SAGES Robotic Research Grant. Dr. Prahbu has received consulting fees from CMR Surgical and Verb Surgical, as well as speaker fees and research support to the Cleveland Clinic from Intuitive Surgical. Dr. Warren has received honoraria from Intuitive Surgical for speaking and teaching.