Monday, August 20, 2012

Evidence-Based Surgery: What Evidence?

Here is a study that illustrates everything that is wrong with the current status of evidence-based surgical practice.

Many of the standard procedures we perform in general surgery are based on observational studies, expert opinion or my favorite “That’s the way I was trained,” and not randomized controlled trials. Although some such research has been done, subjecting patients to sham operations raises ethical issues and would expose patients to anesthesia unnecessarily.

But some topics could be studied prospectively. A recent paper [Variation in the use of intraoperative cholangiography during cholecystectomy. Sheffield KM et al. J Am Coll Surg. 2012;214:668-79] highlights the problem of insufficient evidence in some areas of surgery.

A group from the University of Texas Medical Branch in Galveston looked at differences in the rates of operative cholangiography in their state. They analyzed data from 212 hospitals in which more than 160 cholecystectomies had been done including almost 177,000 such operations over the 8 years from 2001-2008. The surgeon was identifiable in 89% of cases.

Despite the known pitfalls of basing clinical research on administrative data, several interesting findings of this paper are worth discussing.

Operative cholangiograms were done on 44.6% of the total cohort. By hospital, the operative cholangiogram rates ranged from 6.0% to 98.2%. The breakdown by surgeon was limited to the 706 who had done at least 40 cases. The range of operative cholangiogram use by individual surgeons was 0% to 100% with a median of 39%. Medians were higher for patients with gallstone pancreatitis (69%) and lower for those with acute cholecystitis (25%).

Uninsured patients were only slightly less likely to have operative cholangiography than those who were insured. A puzzling finding was that of those patients who had both ERCP and operative cholangiography, 37% had undergone the ERCP before the cholecystectomy and operative cholangiogram. Why would an operative cholangiogram be necessary after an ERCP had already been done?

The authors found that the variation in rates of operative cholangiography was attributed much more strongly to the surgeon and the hospital rather than the indication for surgery. They concluded that the likelihood that a patient would undergo operative cholangiography depended on the hospital she arrived at and who the surgeons was.

The extent of the variation in the use of operative cholangiography could hardly be greater. It is difficult to believe that there is no agreement on the indications. I don’t think this is unique to Texas either.

The literature is conflicting. One can find multiple papers to support any position. Some claim that operative cholangiography helps prevent common bile duct injuries and reveals unsuspected stones. Others say false positive operative cholangiograms result in more procedures and that most asymptomatic stones discovered by cholangiography never cause symptoms. Surgeons who routinely perform operative cholangiography say it does not waste time while those who don’t do them say it does.

False negatives can occur. I have seen patients with negative operative cholangiograms readmitted within a few weeks because of symptomatic common bile duct stones.

I firmly reside on the low end of the operative cholangiography spectrum. I never perform one unless there is a specific indication as dictated by the liver function tests or a significant question involving the anatomy in the operating room.

A large, well-designed randomized controlled trial would help settle the issue, but it will probably never be done.

Who would sponsor such a study? The companies that manufacture the equipment for cholangiography certainly would have no incentive to fund it. Maybe the best we can hope for is a consensus statement from a group of expert surgeons.

Will it ever be forthcoming?

A version of this post appeared in General Surgery News in June of 2012.


Anonymous said...

Brilliant. I use it selectively. I am also concerned about injuring the cystic duct or even the CBD by forcing a catheter out the back end undetected. Any statistics on injuries incurred by cholangiogram?

Skeptical Scalpel said...

There's not much about the complications of op cholangiography. Here's a link to a study reporting 2 major duct injuries in 1715 operative cholangiograms.

Anonymous said...

I was taught to perform cholangiography for:

a. elevated LFT's or jaundice
b. enlarged common bile duct
c. unclear anatomy
d. history of gallstone pancreatitis

So, I "used" to practice this selectively guided by the above.

Since, residency (18 years ago), I have added another: To prevent the crazy f****g patient from coming back to the ER, after surgery, complaining of pain/nausea/blah..blah..blah or wanting more pain meds. Now I do them all the time, so I don't have to deal with ER docs calling me for the rare patient who says, "I still hurt." (Usually the female with prior history of Fitz-Hugh Curtis, IUD, PID, etc.) I can roll over and say, "call somebody who cares."

Oh...and I do lots of incidental appys...I couldn't give a crap if I get paid for them. A night of sleep on a female "chronic pain patient" is worth 10 B.S. appy's that the OB/GYN doesn't want to see. Without an appendix...and a normal CT...with belly somebody who cares.

"Selective appendectomy" vs. "selective cholangiography" same thing.

Skeptical Scalpel said...

I'm not sure how doing a cholangiogram gets you off the hook when a patient you operated on returns to the ED. I try to be sure that patients with gallstones really have symptoms of GB disease. Everyone who has stones doesn't necessarily need surgery.

Regarding incidental appendectomy, I don't do it. You will be in trouble if you ever have a complication from the procedure as very few people are doing them these days.

Anonymous said...

Agree that not "everyone who has stones doesn't necessarily need surgery." Didn't mean to imply they did.

However, I have performed a hundred incidental appendectomies and the argument that "you will be in trouble if you ever have a complication from the procedure" as "very few people are doing them these days".

Why? Why were they once common and now, uncommon. It wasn't because they developed cecal leaks or fistulas..or breakdown of staple was because insurance doesn't pay for them anymore.

Now, figure the cost of ONE incidental appy on a girl with PID vs. the cost of her returning 10 years later with RLQ pain work-up and/or appendicitis? In one scenario,she's in the OR and I use a couple firings of the stapler. In the latter, there is the costs of CT scan, new operation, new hospital stay, etc. One incidental appy pays for itself over and over and over again.

I can't tell you how many times I have sweared because I was operating on an 80 year old with perforated appendicitis because the surgeon refused to take out the appendix when he did the colon resection for diverticular disease and colostomy takedown for fear, as you say, of "be[ing] in trouble." That's not why the surgeon didn't take it out...he didn't take it out because it is "bundled" into the codes.

Thanks for the commentary. Appreciate the civil disagreement.

Skeptical Scalpel said...

You may be right about the fact that they are no longer paid for. I just don't want to add any risk, especially because I only do emergencies and they are all acutely inflamed GBs.

I think there was a paper about 30 years ago that showed statistically that a patient was more likely to experience a complication from an incidental appendectomy than to suffer from acute appendicitis. Many people stopped doing them after that.

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