More about adhesions and postoperative pain

In November 2016, I wrote about adhesions and whether they are the cause of chronic abdominal pain. I and several surgeons who commented felt they weren't.

Some new information from the February 2017 issue of the journal Surgery is just in. A randomized, double blind, placebo-controlled trial from The Netherlands was originally published in 2003 after one year of follow-up. At that time, there was no apparent benefit from an operation to lyse [divide] all adhesions laparoscopically in 52 patients compared to a placebo operation that involved performing only laparoscopy to assess the extent of adhesions in 48.

The current paper looked at outcomes 12 years after the original surgery was done. Follow-up was available for 73% of the patients—42 in the group who had adhesiolysis and 31 who had laparoscopy only.

The authors concluded, “Laparoscopic adhesiolysis was less beneficial than laparoscopy alone in the long term. Secondly, there appeared to be a powerful, long-lasting placebo effect of laparoscopy. Because adhesiolysis is associated with an increased risk of operative complications, avoiding this treatment may result in less morbidity and health care costs.”

Unfortunately the paper has a few flaws.

Is do-it-yourself surgery the future of medicine?

Once in a while, I read something on the Internet that is so silly, so outrageous that I can't help myself. I must speak up.

Such a situation occurred a few days ago when I came across an article called "DIY [do it yourself] Surgery: The Future of Medicine?" on a website called FastCompany.

An "interaction designer" named Frank Kolkman has created a robotic Open Surgery Machine which he proposes could fill in need when "middle-class" US citizens who have no access to healthcare require surgery.

My favorite line from the article is an explanation of what Mr. Kolkman's robot can do. "It's designed to perform simple surgeries like laparoscopic surgery in which three or more small keyhole incisions are made to allow a surgeon to operate inside a part of the patient's body after inflating it with CO2."

He proposes that "appendectomies, prostate operations, hysterectomies, and also colon and general inspections" could be done.

Now I'm really worried about surgical education

Here's why.

A friend told me that a new attending on his staff was having some problems. Although the young surgeon was a graduate of five years of general surgery training plus two years of fellowship, he was unable to do an inguinal hernia or a laparoscopic cholecystectomy by himself.

This is just an anecdote, but the issue has been identified by others. Remember the paper from Annals of Surgery in September of 2013 that described a survey of fellowship directors? It stated that 66% of graduates of five-year general surgery training programs could not conduct a major case unsupervised for 30 minutes, and 30% could not independently perform a laparoscopic cholecystectomy

A study published online in JAMA Surgery last month looked at 20 years of ACGME surgical resident case logs and found that although minimally invasive surgery is being done much more frequently, it is currently performed in more than 50% of cases for only five procedures—cholecystectomy, appendectomy, adult anti-reflex surgery, partial gastric resection, and thoracic wedge resection.

In 2007, the Residency Review Committee for Surgery increased the required number of basic laparoscopic surgery cases from a minimum of 34 to 60 and from 0 to 25 for advanced . The authors expressed concern that there might not be enough minimally invasive cases for all of the residents to do. They also pointed out that there was still in need for residents to learn open surgery since all but five operation procedures are still predominantly performed that way. However, as laparoscopic cases increase, the number of open cases will decrease because the total number of cases done by graduating chief residents has not changed significantly in 20 years.

A year ago, I blogged about some potential problems that might occur when surgical residencies are expanded and new programs are begun. Specifically, I wondered if there would be enough teaching cases to go around. It is interesting to see my speculation bolstered by data.

A program director recently told me that there may be a movement afoot to start a Fundamentals of Open Surgery course.

What is going on here? There is already a Fundamentals of Laparoscopic Surgery course. Do we really need to have a separate course to teach residents open surgery? Isn't that what a "residency" is supposed to do?

How did surgeons of my generation ever learn how to operate without courses in the fundamentals of laparoscopic and open surgery?

The visionary surgeon Leo Gordon saw it coming in 2002. He predicted the need for a "macrolaparotomy" course, and it can be run by the newly created American Board of Open Surgery.

Surgery in space: I foresee problems.

The astronauts are halfway to Mars when suddenly one of them develops abdominal pain and requires surgery. What will they do?

According to NASA, a miniature robot capable of assisting in surgery has been developed, tested in pigs, and is soon to be trialed in a weightless environment. The robot, which weighs less than 1 pound, can be inserted into the abdomen via the umbilicus and controlled remotely.

The press release from NASA said types of operations that the robot would be capable of performing were "emergency appendectomies, emergency cholecystectomies, emergency perforation of gastric ulcers [sic], and intra-abdominal bleeding due to trauma." NASA meant to say "repair of perforated gastric ulcers." Not surprisingly, many science reporters for media outlets, for example, SFGate and WiredUK, did not notice the error. New Scientist also missed it, but at least published a later correction.

However, even the famous da Vinci robot is incapable of performing surgery on its own.

The original idea was that a surgeon on the ground would direct the robot's movements, but that will not be possible for two reasons. In deep space, the time lag between the earthbound surgeon's actions and the robot's response would be too long, and a recent article about remote-controlled drone crashes highlighted the problems that can occur when links are lost or computers malfunction.

The plan is to train the astronauts to perform minimally invasive robotic surgery on each other. What could go wrong?

A lot.

Gallbladder surgery goes back to the future in China

Chinese surgeons claim taking out just the gallstones without removing the gallbladder works well for most patients.

There were 65 patients with gallstones, 61 of whom underwent successful minimally invasive surgery for removal of just the stones leaving the gallbladder in place. The other four patients had laparoscopic cholecystectomies for various technical reasons. After an average follow-up of 26 months, the stone recurrence rate was 4.9% (3 cases).

Not mentioned in the abstract but noted in the methods section of the full article is that all patients were given a 3-month course of ursodiol postoperatively. The authors said it "adjusts the abnormal lipid metabolism in the gut-liver axis and prevents stone recurrence." This statement contains some truth up until the word "and." It's not clear how a short course of ursodiol would help.

Before the advent of laparoscopic cholecystectomy, doctors tried dissolution with ursodiol as a primary treatment. It worked 30-80% of the time for pure cholesterol stones, not those that were pigmented or calcified. About 50% of the time the gallstones recurred after the medication was stopped if the follow-up was long enough, that is, at least 7 years. [I had to go back to 1988 for this reference.]

Well over 100 years ago when open gallbladder surgery was first attempted, surgeons soon learned that removing the stones was inadequate treatment due to a high rate of recurrence.

Since the gallstone removal procedure involved general anesthesia and laparoscopy with two 10 mm and two 5 mm ports anyway, it makes absolutely no sense to just remove the stones. Most laparoscopic cholecystectomies are done with one 10 mm and three 5 mm ports so there is one less large incision which decreases the risk of postoperative hernias.

Here are some more issues.

Preoperatively, only 26 of the patients in the series had biliary colic. Gallstones with "atypical upper gastrointestinal symptoms" were present in 34, and 5 had no symptoms. Surgeons in the US generally would not have operated on patients in the latter two categories.

No mention was made of the duration of the operation, which involves laparoscopy with the 4 ports as noted above, insertion of a choledochoscope into the gallbladder, grasping the stones with a basket an unstated number of times, irrigation, and suture closure of the gallbladder wall.

The authors also that said except for the three recurrences of stones, gallbladder function was normal postoperatively. This was determined by ultrasonography after a fatty meal which took place every 6 months postop.

The three reoperations were done when stones were found by the ultrasound. Of those three, the authors said, "One patient remained asymptomatic, 1 patient experienced biliary colic, and the other patient had non-specific upper gastrointestinal symptoms (flatulence and dyspepsia)."

I don't see this procedure catching on here in the US. Do you?

UPDATE 3/25/14: See a follow-up post on this subject here.

Single-incision vs. standard 4-port laparoscopic cholecystectomy: Part 2

Here's another paper that shows why reading only an abstract can sometimes be misleading.

A prospective trial (abstract here) of 49 patients randomized to single-incision laparoscopic cholecystectomy (SILC) vs. 51 who had standard 4-port laparoscopic cholecystectomy (LC) found that average operative times were 63.5 ± 21.0 minutes for the SILC compared to 43.8 ± 24.2 minutes for those who had LC, and hospital charges were also more than $4000 higher for the SILC patients—both significant differences with p values < 0.0001.

Medical and surgical supplies were the major factors contributing to the increased charges for SILC.

Other than a significantly larger number of females in the SILC group, the patients were similar in baseline characteristics.

Other important considerations such as postoperative pain, hospital length of stay (an average of 24 hours or less for both operations), use of analgesics, cosmetic appearance of the wounds, rates of incisional hernia, and quality of life were similar. Average follow-up was 16 months in both groups. The authors concluded that there was no advantage to SILC.

Since this paper supports my bias against single-incision surgery, I was going to tout it as yet another negative paper like a recent meta-analysis (here) from a group in Croatia showing absolutely no advantage for SILC.

But this sentence from the "Methods" section of the paper foiled my plan. "Before partaking in the study, each surgeon developed his or her SILC technical skills in a laboratory setting and demonstrated proficiency during 5 SILCs under the supervision of a surgeon with experience on more than 50 SILC cases."

This was not mentioned in the abstract.

Are you surprised that a surgeon that might take longer to do SILC, an operation done only 5 times before, than LC, which each of the surgeons had probably done hundreds of times? Although the mean operative duration was longer for SILC, it is a "straw man" in statistical parlance. This may not detract from the rest of the results but certainly has to be considered.

As noted by the authors, the study was underpowered (that is, there weren't enough patients) to detect differences in some of the other outcomes due to difficulty recruiting subjects.

Of 946 patients offered enrollment in the study, only 103 consented. Patients declined to participate either because the surgeon explained that he had done more standard LC procedures, or the patients opted for the SILC because of its supposed cosmetic advantage.

The authors, based at Northwestern University Medical School in Chicago, should be commended for their honesty in explaining their inexperience with SILC to potential subjects of the trial and wonder if other surgeons who perform SILC do this.

This paper also highlights the problems associated with attempts to conduct randomized prospective studies involving new surgical procedures.

Bottom line: The extra costs associated with SILC are not worth it.

Part 1 of this 2-part series on SILC appeared on Tuesday, 2/18.

Single-incision vs. standard 4-port laparoscopic cholecystectomy: Part 1 of 2

The saying used to be, "You can get any paper published if you have enough stamps." Now with electronic submission, you don't even need the stamps.

A retrospective study comparing single-incision laparoscopic cholecystectomy (SILC) to standard 4-port laparoscopic cholecystectomy (LC) concluded that "SILC showed no disadvantage concerning risk profiles, operative times or hospital stay."

According to the abstract, 81.7% of the 115 SILC patients had elective surgery vs. 55.5% of the 344 in the LC group. The SILC cohort experienced significantly shorter operative times (70 ± 31 vs. LC: 80 ± 27 minutes) and hospital lengths of stay (3.02 ± 1.4 vs. LC: 4.6 ± 2.8 days), p < 0.001 for both. LC was converted to open surgery in 21 cases vs. none of the SILCs, p= 0.003. Rates of bile leak and incisional hernia did not differ.

Do you see any problems with this study? I do.

The groups were not really comparable because the LC group underwent more emergency operations. That difference is significant with a p value of 0.007—conveniently omitted from the abstract. The preponderance of elective cases likely accounts for the SILC group's shorter operative duration, lower rate of conversion to open, and shorter length of stay. The SILC patients were also a mean of 10 years younger.

The average operative time for the LC patients, 80 minutes, is much longer than the 40 to 45 minutes reported in most other recent series such as this one. In statistical circles, measuring one's pet theory against a false comparator is known as setting up a "straw man." I've written about this before.

This study was done in Germany, where the hospital lengths of stay for both types of surgery are far longer than those seen in the United States where about 90% of patients go home within 24 hours of laparoscopic cholecystectomy.

The authors concluded that "SILC can be regarded as a natural evolution in the era of minimally invasive surgery."

On the other hand "No disadvantage" is another way of saying, "No advantage."

This paper didn't convince me about the value of SILC. How about you?

Part 2 of this 2-part series on SILC appeared on Thursday, 2/20.

Should all surgeons have video assessments of their skills?

Last month, a superb study by the Michigan Bariatric Surgery Collaborative showed that the more skilled surgeons were, the better were their outcomes.

Surgeons submitted a video of their choice depicting their performance of a laparoscopic gastric bypass. Since it was self-selected, it was presumably their best work. At least 10 of their peers, blinded as to the name of the surgeon, rated skills on the video which had been edited to include only the key portions of the case.

Surgeons in the lowest quartile of ratings for surgical skill had significantly more postoperative complications, readmissions, reoperations, and deaths.

A New York Times article about the paper features a couple of short video clips—one from a not-so-skilled and one from a very skilled surgeon. The differences are obvious and dramatic.

According to the discussion section of the paper, the Michigan bariatric surgeons are now watching each other operate and will soon be receiving anonymous feedback about their technique from their peers.

It is not clear whether this will improve the skills of the lower-rated surgeons or have any effect on outcomes.

Many people rightfully praised the research. Some suggested that all surgeons should be scrutinized in this same fashion.

I agree that the study was well-done and shows that technically better surgeons have better outcomes.

But there are some problems with generalizing this to all surgeons.

The American Board of Surgery recently noted that there are almost 30,000 board-certified general surgeons in the US. This raises a number of logistical issues.

Let's say we focus on the most common major surgical procedure—laparoscopic cholecystectomy, 10 surgeon-raters would have to view at least 15 to 20 minutes of video for each of the 30,000 board-certified general surgeons. How long would that take? Who would collect and edit all the videos? Who would make sure that the ratings were consistent? Who would collate and distribute the results? How would follow-up be done? Who would pay for all of this?

And that is just for the board-certified general surgeons. What about the general surgeons who are not board-certified and all the other surgical specialists? Maybe gastroenterologists should have their endoscopy procedures scrutinized. Maybe primary care docs should have selected office visits recorded too.

This is similar to the enthusiasm which surrounded the concept of using retired surgeons to coach other surgeons. The idea was based on the experience of one surgeon, who had access to an expert coach and wrote about it. I blogged about the logistical difficulties that would preclude coaching from becoming widespread. To my knowledge in the two years since I wrote that post, coaching has not caught on as a performance improvement measure.

It's too bad, because in an ideal world, video evaluation of operative procedures and coaching would be great. Unfortunately, we don't live in an ideal world.

Read the whole paper not just the abstract

Here is another installment in my series of posts about why you should read the entire paper and not just the abstract. (See others here, here and here.)

A paper in the February 2013 issue of the Journal of the American College of Surgeons describes 15 cases of median arcuate ligament syndrome treated with laparoscopic surgery.

Median arcuate ligament syndrome (MALS) is somewhat controversial. It is said to be due to impingement of the median arcuate ligament (a portion of the diaphragmatic crura) on the celiac artery causing a narrowing and decreased perfusion of the stomach. Symptoms are abdominal pain after eating, nausea and weight loss. It is often diagnosed in patients who have been worked up for many other suspected problems without finding anything.

The paper notes that 10% to 60% of people without symptoms have narrowing of the celiac artery.

The abstract reports resolution of the pain for 14 of the 15 patients who had the surgery as well as a significant mean decrease in celiac velocity indicating resolution of the narrowed area postoperatively.

It also mentions that one patient required conversion to open surgery but doesn't say why.

On reading the whole paper, one learns that the conversion to open occurred in the only case that was done with robotic assistance.

The authors state that the 2 mm injury to the aorta was the result of the robotic instrument being too large and "the absence of haptic feedback," which is robot-speak for "you can't feel anything."

That is one drawback of the robot. With robotic instruments the sense of touch is simply not present. Although the fingertips used in old-fashioned open surgery are much more sensitive than instruments used in standard laparoscopic surgery, those instruments do enable the surgeon to at least feel some variations in tissues

The aortic tear led to two liters of blood loss and an operative time of just under 8 hours.

The abstract says all but one patient had complete resolution of pain, but the paper says the amount of decrease in the Doppler celiac velocity "did not correspond to the degree of symptom resolution."

And you can see that the differences in preop (red) and postop (green) velocities are pretty modest in 7 of the 10 patients who had them measured even though the mean difference was significant at a p of 0.005. In addition, the postop values all hover around 200 cm/sec, which, in the presence of symptoms, was the threshold for doing the operation.

In fairness, of the 13 patients who were interviewed, all said they were satisfied with the outcome of the surgery and would go through it again.

In some ways, MALS reminds me of internal mammary artery ligation, which was once touted as a cure for angina pectoris (chest pain of cardiac origin). Over 50 years ago, randomized trials which included a sham operation—incisions were made, but the arteries were not ligated—showed that ligating the arteries was no better than the sham operation for relieving pain.

It might be time for such a trial in MALS, only let's skip the robot for this one.

Thanks to Dr. Michael Burchett for alerting me to the MALS paper.

Breaking news! Operations take longer when residents are involved

Yes, you heard it here first. A new study shows that for six common laparoscopic procedures, resident participation resulted in the surgery lasting from 20% to 47% longer.

The six laparoscopic operations were appendectomy, cholecystectomy, gastric bypass, fundoplication, colectomy, and inguinal hernia.

The paper, published in the Journal of the American College of Surgeons, culled the frequently mined NSQIP database for information on 89,720 operations. The database receives input from a large number of US hospitals, both teaching and non-teaching.

The key results were as follows:

All of the time differences are statistically and clinically significant.

Hospital length of stays for all groups did not show important differences. Cases involving residents were associated with significantly more morbidity for all procedures except inguinal herniorrhaphy and fundoplication. The authors feel that the increased morbidity seen was not clinically significant. It isn’t clear upon what they based that feeling. There was no difference in mortality rates for the two groups for any operation.

In no less than four places in the text, the statements similar to the following were made. “The presence of a resident during a surgical procedure is a surrogate marker for a learning environment in which there are likely to be other health care learners at each of the stations in the operating room.” The other health care learners might be anesthesia residents, medical students, nursing students or others.

This is a completely unfounded assumption. For example, in three hospitals I worked in over the years, we had a surgical residency training program with no anesthesia residents and no student nurses. Conversely, it is certainly possible to have no residents but have training programs for student nurses or scrub techs.

The authors rightly point out that the increased operative duration associated with resident training translates into some inefficiencies. A single operating room might not be able to process as many cases as it could when cases are done by attending surgeons. Also, longer cases might cost someone (third-party payer? patient?) more money since OR costs are tallied by the minute.

The paper concludes, “Additional work must be undertaken to identify strategies to optimize operating room efficiency and to develop alternate strategies to prepare participants for the performance of the procedure.”

And what would those “alternate strategies” be? You can pick up beads on a simulator all you want, but it’s not the same as doing an operation. And assuming open surgery is still being done somewhere, there is no simulator for open surgery.

Over-thinking laparoscopic surgery training

Are we over-thinking the training of residents in minimally invasive surgery? Two recent papers in prominent surgical journals suggest to me the answer is “Yes.”

In the July 2012 issue of Surgery, a paper entitled “Cheating experience: Guiding novices to adopt the gaze strategies of experts expedites the learning of technical laparoscopic skills” investigated whether teaching novices to perform simulated tasks on a laparoscopic surgery training system by using the gaze strategies of experts would improve performance. The Methods section of the paper is well over 2 pages in length. The idea was to have some novices perform tasks by simply discovering how to do them by trial and error. A second cohort of novices was given a template reproducing the gaze-tracking used by expert laparoscopic surgeons.

Those using the gaze templates performed the tasks more quickly and with fewer errors. Here’s a section of text from the Results section. Note: punctuation as per the authors.

“Learning phase. Performance, completion time: Results revealed a significant main effect for block: F(9,225) = 13.97, P = < .01; but there was no significant main effect for group, F(1,25) = 0.89; P = .36; n_p² = .04; and no interaction effect, F(9,225) = 0.86; P = .57; n_p² = .03.”

I thought I knew something about statistics but I have no idea what the sentence [at least I think it’s a sentence] says. What I can see from the figures is that the difference in times for the tasks averaged less than 10 seconds per task and the number of errors was reduced in the gaze-trained group from 2 to 1.5 errors per task. Whether these differences are statistically significant is known only to the authors, but 10 seconds and a difference in errors of 0.5 don’t seem all that important to me.

The second paper, “Correlation of laparoscopic experience with differential functional brain activation” is from Archives of Surgery, July 2012. The link is provided so you can verify that I am not making this up. Investigators put novice and expert laparoscopists in a PET scanner and had them perform a laparoscopic simulated task [moving pegs from one place to another] while undergoing a total of 6 PET scans. The scans involved the injection of oxygen 15 labeled water. Since the full text is available on line, I invite you to view the photos of the set-up of the experiment and judge for yourself how comfortable the subjects must have been.

Rather than paraphrase the results of the study, I will quote the abstract directly.

“The novice group had a significantly (P = .001) higher activation (with deactivation in the expert group) in the left precentral gyrus and insula and the right precuneus and inferior occipital gyrus. The second analysis compared the 2 video scans and the rest scan. In contrast to the expert group, the novices had significantly (P = .001) higher activation in the right precuneus and cuneus but deactivation in the bilateral posterior cerebellum.”

It’s all very clear to me now.

Their Figure 2 shows that despite the differences noted in activation of brain areas, by the third peg transfer test, the novices equaled the scores of the experts on their first peg transfer. The novices also improved markedly compared to their first attempts.

The authors admit that one of the limitations of their study was that 4 of the 5 novices were women while all the experts were men, which may have confounded the results. [Note: the authors said this, not I.]

What does it all mean? They claim that understanding the neural pathways might help in developing better ways to train people. I think that remains to be seen.

In retrospect, I can’t imagine how I or anyone else ever learned to do laparoscopic surgery relying only on someone showing us how. I had no access to expert gaze-tracking templates or PET scans.

I guess a paper on the method “see one, do one, teach one” would not be accepted by a major journal these days.