Monday, April 23, 2012

Read the entire paper not just the abstract

Here is a paper touching on two of my favorite subjects, robotic surgery and misleading abstracts.

It is entitled “Overcoming the challenges of single-incision cholecystectomy with robotic single-site technology” was just published ahead of print in Archives of Surgery. It is a study of 100 robotic single-incision cholecystectomies done by five Italian surgeons.

The conclusion of the abstract:

Da Vinci single-site cholecystectomy is an easy and safe procedure for expert robotic surgeons. It allows the quick overcoming of the learning curve typical of single-incision laparoscopic surgery and may potentially increase the safety of this approach.”

From the full text of the paper, here is a summary of the results of a survey of the five surgeons who participated in the study.

Rating single port insertion technical issues using a scale of 1 to 5 with 1 being easy and 5 being difficult, one surgeon rated it a 2, two said 3 and two said 4.

Regarding the ergonomics of robotic single-site vs. standard laparoscopic 4-port cholecystectomy, two surgeons rated robotic worse and three said equal.

Comparing robotic to standard laparoscopic 4-port cholecystectomy, all five surgeons said robotic surgery was more difficult.

All five surgeons said the robotic procedure was safe based on their having performed a mean of 18 cases with a range of 12 to 42 cases.

The mean duration of the surgery was 71 minutes, which does not compare favorably to an operative time of 40 minutes from series of 238 single incision non-robotic laparoscopic cholecystectomies reported in the Journal of the American Collegeof Surgeons in 2010.

The authors state, “None of the considered [operative] times (total time and each of its main components) appeared to significantly decrease with the number of patients operated on." How is this statement reconciled with the “quick overcoming of the learning curve typical of single-incision laparoscopic surgery” mentioned in the conclusion of the abstract? No such comparison was included in the paper.

This abstract of this paper, much of which is a survey of only five surgeons with a modest experience in robotic single-incision cholecystectomy, is misleading. The paper itself suggests that compared to standard laparoscopic surgery, robotic single-incision cholecystectomy is less ergonomically comfortable, more difficult and takes longer. To say it is safe based on a series of 100 cases is premature at best.

For previous posts on robotic surgery, see the label to the right of this post.

Here is a previous post on misleading abstracts: "Reading an abstract vs. reading an entire paper."


Anonymous said...

Might be misleading if they were comparing robotic single incision to standard laparoscopic surgery, but they were comparing it to single-incision laparoscopic surgery.

Skeptical Scalpel said...

I disagree. If you look at Table 1, which summarizes the entire gist of the paper, you will see that more than half of the comparisons listed are to 4-port laparoscopic surgery. In addition, two of the 5 surgeons had not even done single-incision laparoscopic cholecystectomy before.

The misleading part is also the abstract's assertion that robotic is easy [their own data says it's not] and safe [an N of 100 cases does not prove safety].

Anonymous said...

Well, I'll confess that I don't have a subscription to the Archives of Surgery and I'm not quite committed enough to pony up $30, so I'm reliant on you to tell me if there were any meaningful comparisons in the full text of robotic single site surgery to laparoscopic single site surgery. I gather that they also made comparisons to traditional four port laparoscopic surgery, but surely there must have been some text related to single site laparoscopic surgery.

And to be nit-picky, not being as easy as traditional four port laparoscopic surgery does not mean that it's not still easy.

Skeptical Scalpel said...

I guess they could have used the term "less easy," but they chose "more difficult" instead. The robotic single-port procedure took 75% longer. To me that suggests significantly more difficult.

mdaware said...

I might have made a similar comment on another post at some point -- I'm not a surgeon but I looked into robotic surgery evidence in 2010 when I was working with ABC News, and even the best data (quicker operative times) were misleading -- they measured skin-to-skin, ignoring equipment setup!

Skeptical Scalpel said...

MD, Thanks. That is still true. They like to omit the so-called "docking time," which can be more than 20 minutes.

Anonymous said...

Another misleading detail, is to count the days the patients stay at the hospital. I have personally witnessed how a centre, trying to convince the rest of world of the "fantastic" short hospital duration of treatment following Robotic cystectomies - it turned out that they sent the patients on day 5 or 6 to a resting-home with hospital facilities, nurses and daily medical rounds. The postoperative stay was not different from open cystectomies in any regular centre of the same size keeping the patients full time. That is 10-14 days.

Skeptical Scalpel said...

Yes, length of stay is a "soft" endpoint and can easily be influenced by non-medical issues such as you describe. There are also things like "I can't get a ride," "I don't want to go to that rehab center," "I refuse to go home" and so on.

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