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LETTERS TO THE EDITOR
tectomies recently published in the New England Journal of Medicine was 1.8%.2 This is an order of magnitude lower than has ever been published in a series of surgical patients. This low incidence of common duct stones has been duplicated by other series of laparoscopic cholecystectomies, but is as yet unexplained. It is probably due to selection of patients, and certainly many small stones were not detected and passed spontaneously. I think this experience with laparoscopic cholecystectomy suggests that most stones in the common duct pass spontaneously. Stones that are causing dilatation of the common bile duct or liver function abnormalities should be pursued, as opposed to those that are completely asymptomatic, which have been and will continue to be passed without event.
References 1. Menning JW. Routine choledochotomy with cholecystectomy. Michigan State Medical Journal 1963; 62:752-753. 2. The Southern Surgeons Club. A prospective analysis of 1518 laparoscopic cholecystectomies. N Engl J Med 1991; 324:1073-1078.
THEODORE N. PAPPAS Durham, North Carolina
September 28, 1991 Editor: The article "Choledocholithiasis, Endoscopic Sphincterotomy or Common Bile Duct Exploration" in the Annals of Surgery 1991; 213(6):627-634 was of significant interest to myself and, I believe, many others. In the series presented by the authors Stain, Cohen, Tswshoysha, and Donovan, they stated that 65% of the patients were stone free after sphincterotomy (35% thus had residual stone). They also stated that 88% were stone free after choledochotomy (12% residual stones). This to me is a shockingly high failure rate when we compare this with our study of 150 cholecystectomies and choledochotomies we presented in the August 1965 Michigan State Medical Journal and in subsequent surveys. In the study that we presented, there were no residual stones seen by T-tube cholangiography performed at the time of surgery, and when a repeat T-tube cholangiogram was also performed on the 6th or 7th postsurgical day just before the removal of the T-tube. The question is whether we are getting too careless with exploration and thorough irrigation of the common duct or too dependent on others to solve our surgical problems. JOHN WARREN MANNING III, M.D., F.A.C.S. Saginaw, Michigan Dear
Dear Editor: Dr. Manning's letter concerns the incidence of retained stones after exploration of the common bile duct (CBD). His report, to which he refers, is entitled "Routine Choledochotomy With Cholecystectomy" (J Mich State Med Soc 1963; 62:752). He recommends routine choledochotomy, irrespective of any sus-
Ann. Surg. - July 1992
picion of CBD stones. Among 150 cases, there were 33 cases with stones (22%). The article does not state the number of stones retrieved from the CBD nor does it indicate the results of postoperative cholangiography. The letter states that the latter did not show retained CBD stones. I fear that Dr. Manning has made the common error of comparing dissimilar groups of patients. This danger of comparing "apples and oranges" as related to bile duct stones has been discussed by Cotton and is cited in our report. We reported an incidence of 12% of retained CBD stones in cases with proven common duct stones, not the incidence in a population such as Dr. Manning's, where most cases did not harbor CBD stones. Current figures that are reported for retained CBD stones among cases with stones present approach 10%, as is documented in our text. Additionally, five of our six cases with retained stones had more than than 20 stones present in the CBD. The incidence of retained stones in the latter situation is generally accepted to be even higher than that average, but the exact relationship between the number of stones present and the risk of retained stones is not well documented in the literature. Indeed, a biliary bypass has been recommended by many authorities in cases with multiple stones because of the high likelihood of retained stones.
We would urge that when making comparisons, commentators be sure that they are indeed considering similar populations and that a valid comparison can be made. Precise documentation ofthe relationship between the number ofCBD stones retrieved and the incidence of retained stones would also enhance the quality of future discussions of these matters. STEVEN C. STAIN, M.D. ARTHUR J. DONOVAN, M.D. Los Angeles, California
October 31, 1991 Dear Editor: I read with interest the recent article by Berlauk et al.' on the routine perioperative use of the Swan-Ganz catheter to reduce morbidity and mortality rates after lower extremity revascularization procedures. Although I would like to accept their conclusions (and, indeed, I am currently conducting a similar trial in an effort to resolve this issue), I have several questions about their protocol and results that I am unable to answer after reading their paper. According to their algorithm, both groups I and II (the ones randomly assigned to receive a catheter) had precordial nitropaste applied every 4 hours. It is not stated whether group 3 (controls) also received this drug. If not, is it not possible that this simple treatment could have resulted in the fewer cardiac complications in groups I and II? It is also not clear whether the groups were indeed similar. Was there any difference in length of operation, type of procedure, or intraoperative blood loss between the groups? What was their policy on use of postoperative anticoagulants such as heparin or aspirin? Could these have caused the differences in rate of thrombosis? One would think that the use of a single surgeon would minimize these differences, but it is not stated. I await the authors' reply with keen anticipation. I hope that their work will inspire others to do similar studies in other categories of patients.
LETTERS TO THE EDITOR
tectomies recently published in the New England Journal of Medicine was 1.8%.2 This is an order of magnitude lower than has ever been published in a series of surgical patients. This low incidence of common duct stones has been duplicated by other series of laparoscopic cholecystectomies, but is as yet unexplained. It is probably due to selection of patients, and certainly many small stones were not detected and passed spontaneously. I think this experience with laparoscopic cholecystectomy suggests that most stones in the common duct pass spontaneously. Stones that are causing dilatation of the common bile duct or liver function abnormalities should be pursued, as opposed to those that are completely asymptomatic, which have been and will continue to be passed without event.
References 1. Menning JW. Routine choledochotomy with cholecystectomy. Michigan State Medical Journal 1963; 62:752-753. 2. The Southern Surgeons Club. A prospective analysis of 1518 laparoscopic cholecystectomies. N Engl J Med 1991; 324:1073-1078.
THEODORE N. PAPPAS Durham, North Carolina
September 28, 1991 Editor: The article "Choledocholithiasis, Endoscopic Sphincterotomy or Common Bile Duct Exploration" in the Annals of Surgery 1991; 213(6):627-634 was of significant interest to myself and, I believe, many others. In the series presented by the authors Stain, Cohen, Tswshoysha, and Donovan, they stated that 65% of the patients were stone free after sphincterotomy (35% thus had residual stone). They also stated that 88% were stone free after choledochotomy (12% residual stones). This to me is a shockingly high failure rate when we compare this with our study of 150 cholecystectomies and choledochotomies we presented in the August 1965 Michigan State Medical Journal and in subsequent surveys. In the study that we presented, there were no residual stones seen by T-tube cholangiography performed at the time of surgery, and when a repeat T-tube cholangiogram was also performed on the 6th or 7th postsurgical day just before the removal of the T-tube. The question is whether we are getting too careless with exploration and thorough irrigation of the common duct or too dependent on others to solve our surgical problems. JOHN WARREN MANNING III, M.D., F.A.C.S. Saginaw, Michigan Dear
Dear Editor: Dr. Manning's letter concerns the incidence of retained stones after exploration of the common bile duct (CBD). His report, to which he refers, is entitled "Routine Choledochotomy With Cholecystectomy" (J Mich State Med Soc 1963; 62:752). He recommends routine choledochotomy, irrespective of any sus-
Ann. Surg. - July 1992
picion of CBD stones. Among 150 cases, there were 33 cases with stones (22%). The article does not state the number of stones retrieved from the CBD nor does it indicate the results of postoperative cholangiography. The letter states that the latter did not show retained CBD stones. I fear that Dr. Manning has made the common error of comparing dissimilar groups of patients. This danger of comparing "apples and oranges" as related to bile duct stones has been discussed by Cotton and is cited in our report. We reported an incidence of 12% of retained CBD stones in cases with proven common duct stones, not the incidence in a population such as Dr. Manning's, where most cases did not harbor CBD stones. Current figures that are reported for retained CBD stones among cases with stones present approach 10%, as is documented in our text. Additionally, five of our six cases with retained stones had more than than 20 stones present in the CBD. The incidence of retained stones in the latter situation is generally accepted to be even higher than that average, but the exact relationship between the number of stones present and the risk of retained stones is not well documented in the literature. Indeed, a biliary bypass has been recommended by many authorities in cases with multiple stones because of the high likelihood of retained stones.
We would urge that when making comparisons, commentators be sure that they are indeed considering similar populations and that a valid comparison can be made. Precise documentation ofthe relationship between the number ofCBD stones retrieved and the incidence of retained stones would also enhance the quality of future discussions of these matters. STEVEN C. STAIN, M.D. ARTHUR J. DONOVAN, M.D. Los Angeles, California
October 31, 1991 Dear Editor: I read with interest the recent article by Berlauk et al.' on the routine perioperative use of the Swan-Ganz catheter to reduce morbidity and mortality rates after lower extremity revascularization procedures. Although I would like to accept their conclusions (and, indeed, I am currently conducting a similar trial in an effort to resolve this issue), I have several questions about their protocol and results that I am unable to answer after reading their paper. According to their algorithm, both groups I and II (the ones randomly assigned to receive a catheter) had precordial nitropaste applied every 4 hours. It is not stated whether group 3 (controls) also received this drug. If not, is it not possible that this simple treatment could have resulted in the fewer cardiac complications in groups I and II? It is also not clear whether the groups were indeed similar. Was there any difference in length of operation, type of procedure, or intraoperative blood loss between the groups? What was their policy on use of postoperative anticoagulants such as heparin or aspirin? Could these have caused the differences in rate of thrombosis? One would think that the use of a single surgeon would minimize these differences, but it is not stated. I await the authors' reply with keen anticipation. I hope that their work will inspire others to do similar studies in other categories of patients.
