Discussion
Dr. Timothy C. Fabian (Memphis, TN): This study is obviously quite provocative. Dr. Stone and his colleagues have once again challenged conventional wisdom. How is it possible that a nonabsorbable foreign body could be used to establish integrity of the GI or GU lumens? Ridiculous, anathema, heresy! This sounds as crazy as abbreviating a laparotomy in the face of shock or sepsis by placing a prosthesis or a zipper in the abdominal wall for closure and coming back to fight on a more physiologically even footing; or not exteriorizing a colon wound in an acutely injured patient. The latter two concepts were widely believed to be reckless approaches which violated established surgical principles when they were initially proposed. Well, they are now standards of care which were initiated by Dr. Stone.
Will alimentary tract substitution by PTFE ever become clinically adopted? I don’t know. But certainly the possibilities are intriguing based on the results that he presented here today. I would like to ask Dr. Stone a few methodologic questions related to the study.
Were the fascia secured with running or interrupted suture techniques?
Second, the dual mesh was proven to heal the mucosal surfaces completely, whereas the cardiovascular and dura membrane prostheses had incomplete healing with small central ulcerations over the PTFE. Why didn’t you use the dual mesh in the phase 2 studies? And along that line, if you were going to use this patch clinically to cover a duodenal defect with patch material, what would you use today? Regarding species selection, after wrestling with the 100-pound pilot pig, did you decide to change to the canine model?
Could you please speculate briefly on three areas? First, what about using this for common duct replacement, as that is a common clinical problem? Second, what about somewhat larger defects? And third, what about adjunctive use of things such as growth factors in such models?
I would like to thank the Association for allowing me to discuss the paper. I have long felt that Dr. Stone was often a decade ahead of his time, ground which can be tricky to tread on. And as Samuel Clemens once said, “The man with a new idea is a crank until the idea succeeds.”
Dr. Maurice J. Jurkiewicz (Atlanta, GA): With this presentation, Harlan Stone has reinforced his standing as a world-class surgical iconoclast.
In my interaction with Harlan Stone well over a decade in the 1970s, I had a very rich and rewarding experience. Harlan Stone is a consummate generalist. He has a probing mind and has a well-developed sense of challenging established surgical dogma.
As one who has dealt extensively with holes in the upper aerodigestive tract, my initial response was exactly like his, that this was in fact a ridiculous idea. As I read more in the manuscript and reflected on it, there may well be room for such approach in fixed areas in the oral pharynx and the upper aerodigestive tract.
The palate is such a fixed area. Cleft palate, oral-antral fistula after resection of cancer—difficult areas to repair, particularly the latter. The mucosa is not as specialized as the mucosa of the lower gastrointestinal tract. Squamous epithelium might be able to proliferate over such a patch. However, in the remainder of the upper aerodigestive tract there is considerable mobility in the act of swallowing, for example, and second, juxtaposition to major vessels in the neck.
An approach was attempted in the past with a single-stage reconstruction of the cervical esophagus in 1952. However, the net result was erosion of the tantalum mesh covered with a skin graft into the vascular system, which resulted in exsanguinating hemorrhage. This leads me to certain questions.
In mobile areas of the gastrointestinal tract, lower down in the abdomen, you showed heaped-up mucosa at the edges of the patch. I wonder if this heaped-up mucosa could not act as a focus for intussusception because of its polypoid configuration.
A few years ago I was interested in short-gut syndrome. We developed a model in dogs where we created a blood supply to the antimesenteric border of the small intestine. And then the idea was to use skin expanders, modified, of course, put them in, and try to expand the gut to double its width. What happened? This was a 100% model for the creation of intussusception. Will a patch of Gore-Tex in a mobile portion of the intestine act as a focus for intussusception?
Again, a very, very intriguing presentation, Harlan. Thank you very much for bringing it to our attention. One last question. What is your next step? What are you going to do next?
Dr. Hiram C. Polk, jr. (Louisville, KY): For 35 years Dr. Stone has been my best friend. And he has spent almost all of that time a decade ahead of the rest of thought in American surgery. That includes all of you. He really has been innovative and creative in the extreme.
He also, from a Journal editor’s point of view, is almost the only person you can send an off-the-wall manuscript to and know that it will get a straight evaluation. Back to the Journal editor issues, it has been mentioned many times, and Harlan is kind enough to give credit to AJS for the creation of this.
There are two things worthwhile. We have spent so much time dealing with petty salami-slicing, but how to deal with really, really creative off-the-wall kind of proposals doesn’t get much attention. It is interesting that this is the direct result of the decision of the lady who was president of Turkey nearly a decade ago, to insist that the only way in Turkish medical schools you can now achieve something like tenure is through English language, preferably American medical publications. So we see lots of things from people who are now not the traditional staged sort of American approach to given things. This is where this came from. And Harlan, of course, is the ideal person to try to take that on.
I also want to say how important he is as the second, or third, if you will, concurring report as to the utility of this material. It is always the concurring report that is more important than the initial one. The report by Bill Ledger 30 years ago about confirming our observations on the value of prophylactic antibiotics is the most important paper I ever read. It is the confirmation that is much more important than the original report. And the fact that someone else can critically do this in a respected environment is really special.
The hard part for Harlan and all of us is the fact that this is bought and paid for by Gore-Tex. You lack any degree of independence and any degree of being able to tackle this straight up. The Journal editors are beginning to grapple with the pervasive effect of industry in these kinds of endeavors, and it is extraordinarily hard for even the most moral and straight-minded of us to separate ourselves from those obligations. Harlan made it straight up front what he has done, and sometimes you simply can’t deal with this other than to be extra-careful to admit a potential conflict exists.
The final negative point about this is the ungodly cost of this material, which is totally unjustified. And if it is going to be used, it needs to be dealt with in something like a sensible way. This is first-class work, but it has been typical of what Dr. Stone has done for three decades. My congratulations.
Dr. David V. Feliciano (Atlanta, GA): You put these patches in heavily vascularized structures. When PTFE patches were used to replace bile duct holes in the dog lab, they all failed with stricture and dehiscence. And I am wondering if your success may be unique to GI tract replacement because of the vascularity.
Second, there are tremendous species differences in the results that you get when you put in prosthetics such as vascular tube grafts. Do you think that is going to be a factor here, and maybe you ought to move up to higher mammalian models as the next step?
Dr. Max R. Langham, JR. (Gainesville, FL): I enjoyed this a great deal. I wanted to ask Dr. Stone whether he thinks that Gore-Tex as a material is as important as the concept of using a patch. Mike Chen in our group has used SurgiSys, which is a collagen matrix, to do very similar work in a dog esophagus. This has been published in the Journal of Surgical Research, and I think that the concept is a great one. I was just curious as to whether the material is the important thing or if an absorbable material might accomplish the same goal.
Dr. H. Harlan Stone (Phoenix, AZ): First, I want to thank the discussants for staying so late in the morning for my show and tell.
Dr. Fabian, you had a number of questions and suggested application to different animals. That must be a dig at me, because when you were a fellow in Atlanta, I conned you into being immunized against rabies. The monkeys we were to use had been in the test for efficacy of a new vaccine against rabies. Thus, we both were immunized against rabies. As you will recall, word soon went around that our barks were far worse than our bites.
We did use running sutures. Patch selection was based on our not wanting to have a patch extrude and be loose in the bladder. There was one animal we thought might have had dysuria. We gave it a single dose of Pyridium and never did it show such signs again.
I think to close a duodenal defect or stump I probably would use a DLM patch. A Colombian surgeon told me he had used one to close a duodenal stump and another to correct a stricture in the duodenum due to ulcer. Both were reputed successes. So I think it could have some human application in this area.
Regarding its application to the bile duct, I don’t know. I think that may depend on the patch chosen. I would worry if the patch were to extrude into the lumen and thereby create a problem with obstruction, that is unless you had done a papilloplasty before or the patient were later to have an endoscopic papillotomy.
I don’t know how large a defect can be safely spanned. We went to 2-cm squares, which is 4 cm2. We would like to test larger areas as well as insert one circumferentially for a distance. These extensions are on the planning board. I don’t know about growth factor; it may indeed play a role.
At Emory, Dr. Jurkiewicz was always one to ask a question at Grand Rounds for which you never had an answer. I thought he would be the perfect one to put this to other uses. This perhaps might offer a readily available modality for reconstruction of the oral pharynx. Its use for a palate reconstruction certainly should be pursued. I don’t know about tantalum mesh. It certainly did provide many around-the-world trips for a famous Baltimore surgeon.
With respect to intussusception, that indeed could be a problem. We see such occur with polyps. None of our animals had it complicate their course, but they weren’t followed that long. If one used the DLM patch, then they would not have the heaped-up mucosa.
I don’t know what the next step will be, other than we are planning to replace esophageal segments and repair divots taken out of the trachea.
Hiram, thank you for your kind comments. After all, it was your sending me this article to review that started it all. The Gore people have been very supportive of our effort. I had control over everything except one item, that being the administration of the antibiotics. Their protocol was such that the animal had to receive 12 days of enrofloxacin. For those of you who are not up on enrofloxacin, it is veterinary Cipro. Otherwise, they gave me total freedom.
David, I mentioned before about the common duct. You may have used a differently fabricated product, because DLM is a new mesh. That may well have made the difference. I think the patch would be great for certain procedures, such as stricturoplasty, thereby obviating the need to do a Roux-en-Y in the difficult patient.
As far as species differences, there probably are. We noticed a different response between what was reported for rabbits, dogs, and the pig, but these also were different patch sizes. As far as other fabrics, I do not know that much about them. I am sure there are other materials that could be used, but I am just not familiar with any of them.
Again, I want to thank you for staying so late this morning—and particularly for my son, who must soon catch a plane to return to Phoenix.