Which procedure would the nurse anticipate to confirm the diagnosis of Hirschsprung disease congenital Aganglionic Megacolon in a 1 month old infant?

Discussion

Dr. James A. O’Neill, Jr. (Nashville, Tennessee): This manuscript details a 10-year experience with 78 infants who had primary endorectal pull-through procedures at four different institutions, although half of them came from the University of Michigan Children’s Hospital.

Now, while primary pull-throughs for Hirschsprung’s disease have been performed for many years, beginning with Dr. Swenson of this organization, the earlier efforts were all in older children, and this was done very selectively because of the attendant morbidity encountered at that time. The reason primary pull-throughs were not done was that there was higher mortality and morbidity. But over time, with improvements in anesthetic management and other aspects of care, two-stage pull-through procedures have been performed at an earlier and earlier time. So this revisiting of primary pull-through is understandable, particularly in the infant, and it has gradually been undertaken by most pediatric surgical centers, but there is no question this is the largest series.

If you look at the results of two-stage operations over the years—and they have been well tabulated—the results have been excellent. So the benchmark figures are good ones for your comparison. With the exception of postoperative enterocolitis, complications, results, and everything else are essentially identical to two-stage operations. This is excellent considering the small size of your patients. So overall the results with up to 10 years of follow-up are such that you certainly deserve everyone’s congratulations for a pacesetting report.

I would like to pose a few questions to clarify a few things for us. First, the manuscript indicates that this series of primary pull-throughs is not consecutive but that patients with severe enterocolitis preoperatively were treated by staged procedures. Would you share with us the current indications you use for primary pull-through in infants?

Secondly, can you really be sure that patients from four different sites were being selected for operation with exactly the same criteria and that they were evaluated in exactly the same way?

Third, this is not a randomized study and the comparison is with historical controls, but no details are given as to whether the controls were age-matched and whether everything was the same when the historical group was treated, except for that overlap period, as at the present time. Would you tell us about that? Wouldn’t the validity of this procedure be best evaluated in a randomized fashion?

Finally, the incidence of postoperative enterocolitis in this series is of concern, as you have pointed out. Previously, your group at Michigan has reported a 17% to 20% incidence of postoperative enterocolitis with two-stage procedures, and you have gotten that up to 26% with perhaps stricter criteria. Presumably you have been using similar criteria all along, so the incidence of enterocolitis at 42% is certainly something which bears closer investigation. Do you have any other explanations for this? For example, the way you treat—it is identical to the way that Clostridium difficile is treated. Were any of your patients surveyed for this?

Presenter Dr. Daniel H. Teitelbaum (Ann Arbor, Michigan): Your first question related to the fact that this wasn’t a consecutive series and how did we overall go about selecting which patients might be best for a primary pull-through as opposed to a staged approach. I think that we still remain very conservative about which patients we decide to perform a primary pull-through on. As you well know, many of these patients are quite small in size and often quite debilitated at the time when they present to us.

I think our threshold for performing this procedure would have to be those patients that present fairly early in life. Once we get beyond 3 or 4 months of age, the colon has become so dilated in nature that to safely perform an anastomosis into a relatively small anal diameter would really put the patient at very high risk for leakage.

The other contraindication is those patients that present with enterocolitis. We did have one death in our series, and that was a child who developed a necrotizing fasciitis. I do have to believe that that was due to perhaps being overzealous in performing a primary pull-through in a fairly small child.

In order to examine adequate numbers, we did utilize four different sites. We were very careful about the sites we selected. First, each of the sites had surgeons that were taught the procedure by the senior author, Dr. Arnold Coran. This allowed for a very high degree of uniformity in the way the procedure was performed. Second, before we performed any of our analyses, we went back and looked at the demographic data from each of the particular sites and found that they were extremely well matched. There was no difference in the age of the patients, the age at the time of the pull-through, or the level of the aganglionosis in each of the sites.

The controls are another story. Those were historically based as the bulk of our patients who are now undergoing primarily pull-throughs. And you are right, the best way to do this would be to perform a randomized series. I think the problem is that the shift in the United States is really going towards a primary pull-through and it will be difficult in most places to present a particular option of a two-stage pull-through when one might do just as well with a single-stage pull-through.

Although we did find a higher incidence of enterocolitis in our primary pull-through procedures, I truly think that those patients who suffered from severe enterocolitis were not significantly different; it was more likely the manner in which we declared a patient having enterocolitis. The other three sites, aside from Ann Arbor, had a 26% incidence of enterocolitis, which was identical to our two-stage pull-through procedure group. It can be a very subjective matter of whether somebody has enterocolitis or is having abdominal distension or increased diarrhea from another cause. There was not a higher incidence of Clostridium difficile in our study.

Dr. Robert J. Touloukian (New Haven, Connecticut): I concur with Dr. Teitelbaum and Dr. O’Neill that performing primary pull-through is a trend that is occurring in all children’s hospitals by qualified pediatric surgeons who have experience in treating Hirschsprung’s disease. However, the risk of enterocolitis in these patients is of serious concern to us and needs to be studied very carefully, and I am grateful to Dr. Teitelbaum and his colleagues for having done this study. However, we must recall that there are certain safeguards inherent in the two-stage operation.

First and most important is confirmation of the pathology at the colostomy. This allows the surgeon to review the final pathology and be absolutely certain that normal ganglion cells are present and there is no evidence of neuronal intestinal dysplasia, which indeed increases the risk of postoperative enterocolitis.

Second, patients who have a two-stage operation generally can be monitored for adequate weight gain as well as adequate decompression of the proximal colon in the ganglionic area, so that the pull-through is done electively and at a time when the patient’s condition is optimal.

Third, the anal reconstruction is done, of course, at a slightly older age, which reduces the risk of anal stenosis.

I have two questions: One, have you correlated the pathology from the four different institutions to be certain that you have adequate ganglion cells at the pull-through site and there is no increased incidence of neuronal intestinal dysplasia?

Number two: How have you studied these patients preoperatively to be certain that their colon is adequately decompressed prior to their pull-through procedure, either by plain film radiography or by determination that they are in an edema program that has been successful?

Number three: Do you routinely calibrate or dilate the patient postoperatively to reduce the risk of anal stricture?

Dr. Teitelbaum: To answer your first question, I do think that there is a high degree of anxiety when one performs a primary pull-through. One has to be sure that these are performed at a site where a pediatric pathologist is readily available, or at least a pathologist who is highly capable of telling what true ganglion cells are and whether there are hypertrophied nerves suggestive of a transition zone. Despite our operating at a multitude of different sites in Michigan, we routinely send our patients down to the University of Michigan when we do a pull-through to make sure that we have a pediatric pathologist looking at our pathology specimens.

We did not read all the specimens at our study site. However, there have been no misreadings in this cadre of 78 patients, although I would be remiss in saying that we haven’t had misreadings done in other patients who have had a two-stage procedure performed.

I routinely get a barium enema on all of my patients because I want to assess the degree of colonic dilatation, and it also gives me a road map of where the site of aganglionosis ends before I begin my pull-through procedure. Additionally, adopting Dr. Langer’s more recent perineal approach (J Pediatr Surg 1999;34:148–52), I like having the road map of knowing whether this is a left-sided colonic disease, that can be approached primarily from a pure peritoneal approach, as opposed to requiring a laparotomy or laparoscope.

Finally, I calibrate all of my patients postoperatively on a fairly routine basis. And following what was published by Dr. Marty and Dr. Johnson a few years ago, I have been very aggressive in having many of my patients undergo rectal decompression with washouts for the first few months after their pull-through. I think this leads to a significant decrease in the number of enterocolitic complications.


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Table 1. PARENT TELEPHONE INTERVIEW AND STOOLING GRADING SHEET

Which procedure would the nurse anticipate to confirm the diagnosis of Hirschsprung disease congenital Aganglionic Megacolon in a 1 month old infant?