| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||
Ann Thorac Surg 2000;70:842-843
© 2000 The Society of Thoracic Surgeons
Discussion
DR CHANDRA MULLANGI (Dallas, TX): Congratulations on a very nice paper. As you know, we have used 2-D and 3-D in the laboratory setting in Dallas, TX, in relation to robotic systems. Personally I had the same experience with the 3-D in a bench model. We decreased the anastomotic times significantly, but when I took it to the acute animal laboratory, it was a different story. In the acute animal laboratory we did a total of 47 anastomoses, of which seven were using 3-D with the Vista system. One of the limiting factors we had was a resolution. In the acute animal it was a different factor. And the other one is all these seven anastomoses, this is a very limited experience. These were done with three different surgeons who are used to 2-D. Two of them felt it was great in terms of the handling of the instruments and then the sutures and all that, but one surgeon felt that the head-mounted display was very cumbersome. The surprising thing to me was that 3D visualization did not change the anastomotic times in this limited experience. What I feel is, even though a surgeon is experienced in 2-D, there is a further learning curve to learn 3-D usage. I would like your comment on it.
DR BOYD: Doctor Mullangi, we have learned a lot from the pioneering work in video-assisted cardiac surgery that you have done with Dr Michael Mack at the Medical City of Dallas. Your group is to be congratulated for its important contributions. Our own experience, and the experience of most other groups, including Dr Damiano’s team in Hershey unequivocally demonstrated shorter anastomotic times when 3-D rather than 2-D systems were used to perform microvascular endoscopic procedures. Three-dimensional visualization systems improve surgical video dexterity by improving motion control along the visual (z) axis. This advantage persisted along the learning curve and showed no signs of convergence with experience. Your point regarding the resolution provided by the 3-D head-mounted system we used is also very important. We agree that it is inferior to the resolution provided by current three-chip, 2-D systems displayed on conventional 21-inch monitors. The visualization technology used with the robotic system in the present study, however, employed two three-chip cameras and reproduced these images on two separate CCD display screens that immersed the operator in the visual field. This system combined the advantages of high resolution enjoyed by three-chip 2-D cameras with the improved hand–eye control in the z-plane afforded by 3-D visualization. Our study results also show that there was a learning curve with 3-D as well.
DR RANDALL K. WOLF (Columbus, OH): I enjoyed the presentation. I think you have helped to answer a little bit of a debate that we have, and I would like to get your comment on this. When we work with these robotic systems, there are two principal ways to get feedback. There is visual feedback and there is tactile feedback. Really the core of what we are talking about here, and what you are demonstrating, is that visual feedback is very important. In fact, in the computer systems that we use now, I believe that 95% of our feedback is visual. Therefore, anything that we do that improves the vision will be very helpful, because we really don’t have much tactile feedback. Do you agree with this?
DR BOYD: Doctor Wolf, your work in applying and teaching endoscopic skills in cardiac surgery has been unparalleled, and I thank you for being one of my mentors in these techniques. I agree that visual feedback is critical to the success of endoscopic microvascular procedures. Present haptic sensing technology allows the detection of approximately 0.6 N of force; this roughly translates into 4 mm of soft tissue deflection. This degree of sensitivity however, would not facilitate robotic microvascular endoscopic procedures. Visual tissue cues, on the other hand, are sensitive enough to detect a soft tissue deflecting force of about 0.2 N. In our clinical experience to date with 20 totally endoscopic beating heart coronary bypass procedures, we unfortunately have been unable to complete over half of our selected cases using the larger 3-D endoscopes. In closed-chest surgery, intrathoracic space in the anterior–posterior plane and intercostal space can be significantly limited, requiring the use of 5-mm. 2-D endoscopes with 30 degrees of angulation. The ideal visualization system for clinical application would incorporate high-resolution 3-D technology, be no more than 5-mm in size and have variable viewing angles. Until this is available, however, endoscopic surgeons will use visualization systems that allow the surgery to be completed, even if it means using high-resolution three-chip 2-D cameras with conventional 5-mm 30-degree endoscopes.
DR DAVID A. FULLERTON (Chicago, IL): Now that you have some human experience I wondered, A, if you could share that with us, and B, how did you think that your model prepared you for that? In other words, was this a good simulator to teach with?
DR BOYD: Thank you for your question. We have employed a very graded approach to the integration of robotics in human cases. As I mentioned in my presentation, we recently performed a totally endoscopic beating heart robotic procedure. Presently this is not easily accomplished. It is really a proof of concept. I don’t in any way think that people are going to run right out tomorrow and be performing robotic endoscopic anastomoses. The surgical skill set required to do that, though, is very readily learned; we went through a learning process that involved off-pump surgery, off-pump surgery with minimal access, and off-pump surgery with minimal access and the Aesop 3000 robotic arm. We then combined the Vista system to do video-directed anastomoses in the laboratory about 60 times. Then we took that further to cadaveric studies and experience with the telemanipulators, and then gradually moved it into the clinical realm.
I believe that there is a systematic process that all surgeons can follow that will enable them to do this, but first, a paradigm shift must occur which involves introducing underscopic skills into cardiac surgical practice. Randy Wolf is one of the pioneers of that shift from doing conventional surgery without scopes to surgery with scopes. It is a learnable skill, but I would like to emphasize that a very careful and integrated and stepwise path should be taken to totally endoscopic surgery.
Related Article
Ann. Thorac. Surg. 2000 70: 839-843.
| ||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |
