Robotic Surgery in Cardiology
Introduction
With the rapid advancement of technology, cardiac surgery is also entering a revolution in methodology and healthcare. Over time, technology has evolved to improve the way that these surgeries are conducted. In the case of Coronary Artery Bypass Grafting (CABG), many surgeons are slowly switching to Off-Pump Coronary Artery Bypass Surgery (OPCAB), where bypasses are performed without the use of the heart-lung machine. However, the patient's chest is still opened and to reveal the heart which leads to a relatively long recovery time. Recently, many coronary artery problems have increasingly been treated by angioplasty, which is a minimally invasive procedure. During these surgeries, rather than bypassing the occluded artery, patients are outfitted with stents that forcefully push the artery open, allowing blood to flow through the once-blocked arteries. Angioplasties can't be performed on all patients with coronary artery disease, and other options like CABG or OPCAB are needed. With those options, came the downside of having open chest surgery, until now. With the introduction of robotics into this field of medicine, surgeons have been able to replace sternotomy and thoracotomy with small incision entries. As a result, there has been decreases in patient trauma and morbidity. Most initial robotic procedures were limited to harvesting veins and arteries for grafts. However, with advents such as the da Vinci Surgical System, the role of robotics in cardiac surgery is becoming more useful.
Science and Technology
The entry of robotics into the field of cardiology has been a gradual scaled process that can be broken down into four levels: Direct Vision and Mini-Incisions (Level 1), Video-Assisted and Micro-Incisions (Level 2), Video-Directed and Port Incisions (Level 3), Video-Directed and Robotic Instruments (Level 4). Each level increases in complexity and robotic involvement.
Level 1 Direct Vision and Mini-Incisions:
This level encompasses conventional minimally invasive surgery. Using, mini-sternotomies, parasternal incisions, and mini-thoracotomies, the first minimally invasive aortic valve operations were performed through this conventional tactic1. However, this technique in cardiac surgery proved that operations could be performed through smaller incisions and therefore, acted as a springboard to the next level.
Level 2 Video-assisted and Micro-Incisions:
Though now videoscopy could by used to enlarge the vision of the surgical field, the benefits were limited to simple repairs and replacement. Complex repairs, such as quadrangular resections and chordal replacements, were performed with few complications2. Nonetheless, surgeons still awaited 3D imaging and robotic instruments.
Level 3 Video-Directed and Port Incisions:
Imaging modalities such as CT scans have contributed greatly to the planning and registration of procedures. This stage saw the first integration of a robotic arm in carrying out procedures. In addition to the robotic arm, surgeons used an endoscope and a conventional two-dimensional monitor to view the procedure. Devices such as Aesop enabled surgeons to increase precision and control for hand tremors through robotic actions triggered by voice-activated commands. Though the complexity of the devices cannot be compared to the Level 4 technology, these endoscopic techniques allows a wide range of minimally invasive surgery.
Level 4 Video-Directed and Robotic Instruments:
Current cardiac surgery involves the use of complex 3-D imaging techniques and robotic devices. Though just a few years ago Computer Intuitive's Zeus Surgical System was the leading device in cardiac surgery, the economic landscape has changed and now Intuitive Surgical's da Vinci Surgical Device dominates the area of robotics in cardiac surgery.
Source : Bauernschmitt, R, Feuerstein, M, Schirmbeck, EU, Traub, J, Klinker, G, Wildhirt, SM, Lange, R. ÒImproved Preoperative Planning in Robotic Heart Surgery.Ó German Heart Center Munich and Institute for Informatics I, Technical University. http://wwwnavab.in.tum.de/twiki/pub/Main/MarcoFeuerstein/bauernschmitt_2004_cinc.pdf
Robotic Mitral Valve Surgery
Mitral valve surgeries have always been a staple of modern cardiac surgery. However, until now, the only way to either repair or replace a heart valve was to open the chest of the patient and put them on a heart-lung oxygenator. Now, with the advent of new robotic technologies, many centers around the world are beginning to turn to an alternative--minimally invasive mitral valve surgery using videoscopic tools like Aesop®, and robotic tools like the da Vinci® Surgical System. Rather than having to open a patient's chest, patients only have to receive small incisions in their chest roughly 2.5 inches long. Robotic arms can be manipulated inside the cavity, performing operations that may otherwise be too difficult, whether because of physical abnormalities are misfortunate location.3
Previously, less invasive procedures were brought into ever widening use with endoscopic instruments, but there were downsides associated with them. They only had 4 degrees of freedom, while 6 degrees of freedom are required to fully allow free function and orientation in space. Working through a fixed entry point caused problems in the standard endoscopes, both for the surgeon and also the machine. However, the new computer-enhanced instrumentation system allows machines to overcome many of these limitation, including fixed entry points and also the deterioration of human motor skills that is commonly associated with endoscopic surgery.4
The systems can be classified according to the tasks they help perform. The first group is comprised of assisting tools that hold and position various instruments, including the Automated Endoscopic System for Optimal Positioning (AESOP 3000), which is used to guide an endoscope by voice activation. The second group including telemanipulators invented to perform fine manipulations and movements under remote conditions. With these, the operator can remotely direct the robot's movements. There were currently two telemanipulators on the market, the Zeus robotic system and the da Vinci. However, after the Computer MOtion and Intuitive surgical merger, da Vinci dominated the market.
With these systems, the surgeon is placed remotely away from the patient, seated at an operation console with a 3D camera array. This allows the surgeon to see everything as clearly as if s/he were actually operating on an open-heart, all while removing the need to actually open the chest and expose the patient to operating room air. Not only is the surgeon able to access hard to reach places, but is also able to combat the limitation in vision encountered by traditional endoscopy.
A video of a mitral valve replacement can be seen here.
da Vinci Cardiac RevascularizationRecently, a new technology has allowed for a minimally invasive treatment of occluded arteriesÑda Vinci Cardiac Revascularization (dVCR). Using the da Vinci Surgical System made by Intuitive Surgical, dVCR is currently being used for Single-Vessel Small Thoracotomies (SVST) and Multi-Vessel Small Thoracotomies (MVST). Both procedures use the da Vinci robot from start to finish, from the harvesting of the internal mammary artery, to coronary anastomosis and revascularization.
The biggest benefit of dVCR is undoubtedly the ability to be minimally invasive. The 3D imaging system allows surgeons to perform procedures inside a closed chest, with hand movements that parallel conventional surgery. Only a few incisions are made into the patient, ensuring a much faster recovery time. The FDA first approved the da Vinci Surgical System for assisting in cardiothoracic surgery in 1997, while approving it for the full surgery in 2000. 4
Another upside of the new technology is the ability to use stabilizers to ensure that the patient can function without use of the lung-heart machine, something that has often been cited as being more detrimental to immediate patient post-operative health than anything else. With the ability to both avoid open heart surgery and pump use, da Vinci cardio revascularization has fast become one of the most exciting cardiac surgery innovations out there. 4
Ventricular Pacing
Another big part of cardiac surgery is ventricular pacing. Using traditional methods typically used with pacemakers, three leads are used for biventricular pacing - one on each ventricle, and one to provide outputs to both the left and right ventricles at the same time, to assure that the ventricles pump simultaneously. However, physical issues that varied from patient to patient made it difficult to implant this third lead. With the advent of the da Vinci Surgical System, this procedure can now be performed whereas before it was nearly impossible.
Cardiac resynchronization therapy uses the same pacemaker technology as the current industry standard does. However, it also makes use of a third lead on the left ventricle. It provides outputs to both ventricles at the same time to make sure that both ventricles beat at the same time and are operating at a higher efficiency. However, patient-to-patient variations in their anatomy oftentimes make the vein inaccessible 15-20% of the time using traditional percutaneous methods. For those patients with severe heart failure, this ultimately leads to an unsuccessful pacemaker implant.
Using the da Vinci Surgical System, surgeons can attach the third lead to the outside of a beating heart. Targeting the posterolateral wall, the da Vinci Surgical System allows helps those patients with severe heart disease and anatomical irregularities to have pacemakers implanted.
Robotically assisted left ventricular epicardial lead implantation for biventricular pacing: the posterior approach. Ann Thorac Surg. 2004 Apr;77(4):1472-4.
|
|
Ster ASD |
ROBO ASD |
p* |
STER MVr |
ROBO MVr |
p* |
|
Age |
42 ± 13.3 |
46.6 ± 10.5 |
0.433 |
59.8 ± 17.5 |
52.8± 11.2 |
0.302 |
|
Male |
40% |
40% |
1 |
30% |
80% |
0.642 |
|
Female |
60% |
60% |
|
70% |
20% |
|
|
Prior MI |
0 |
0 |
NA |
30% |
10% |
0.096 |
|
Prior CABG |
0 |
0 |
NA |
10% |
0 |
0.305 |
|
EF |
56.6± 6.5 |
59.2± 5.3 |
0.613 |
46.7± 15.4 |
57.9± 6.4 |
0.094 |
|
HTN |
40% |
40% |
1 |
60% |
20% |
0.092 |
|
DM |
0 |
0 |
NA |
10% |
0 |
0.305 |
|
PVD |
0 |
0 |
NA |
0 |
10% |
0.305 |
|
CVA |
30% |
40% |
0.858 |
10% |
0 |
0.305 |
|
Cigarettes |
10% |
0 |
0.305 |
30% |
10% |
0.096 |
Summary of Cost Analysis for ASD Closure and MVr Using Robotic and Conventional Techniques
Cardiac surgery for the patient is about the same with or without robot assistance as shown in the table above. However, overall the cost is slightly greater for robotic assisted surgery than for conventional surgery. In the analysis of cost in . "Does Robotic Technology Make Minimally Invasive Cardiac Surgery Too Expensive?," robotic technology did not significantly increase total hospital cost. However, the costs were higher for robotic assisted cardiac procedures when the investment for the robotic surgical system through amortization of institutional costs is taken into account. 7
Absolute cost for robotic surgery was a bit higher than conventional techniques. However, the OR time, which is the major driver of cost over time. So, after taking into account the institutional cost of the robot, other benefits, such as post-operative quality of life, shorter OR time, and a quicker healing process, the robotic system is pretty cost effective.7
Complications and Success Rates
As Kypson said in his paper, "Robotic Cardiac Surgery," "Currently, the world experience with robotic mitral valve surgery is mostly anecdotal, retrospective, and noncontrolled. Nevertheless, surgical results thus far have been encouraging and are hastening the way toward a completely endoscopic, robotic mitral valve operation."4
The first 38 mitral repairs done by Kypson and his associates were recently published in which they showed that robotic surgery could be done quicker and more efficiently with experience. In their experience, leaflet repair times fell significantly from 1.0 hour to 0.6 hours. Both cross-clamp and bypass times also decreased significantly with experience as well. For all patients, the total length of stay was 3.8 days, with no difference between the two groups. Importantly, there were no device-related complications or operative deaths. With a new technology like robotics, it's important that operations be carried out without any problems, and it's clear that the da Vinci system is very reliable and can only get better as surgeons gain more experience. 4
Many other studies have been conducted by Kypson's group, relating to both surgeon experience, patient experience, and the success of the surgery. While overall, there were no noticeable complications, and no overwhelming show that traditional surgery or robotic surgery had more success over the other, it is still interesting to not that robotic surgery is quickly becoming a very important role in the future of cardiac surgery. 4
Future:
The sheer size of robots in this technology presents a problem for cardiac surgery, especially in the area of pediatrics. Surgeons look toward smaller instruments with tactile feedback as well as a reduced cost of equipment. Though most large hospitals are able to handle the costs, smaller ones cannot afford the $1million investment. Much research is going into addressing these problems so that robotic cardiac surgery can become more prevalent in the future.6