Monday, July 23, 2012

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; np2 = .04; and no interaction effect, F(9,225) = 0.86; P = .57; np2 = .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.

4 comments:

RegionsTrauma said...

And it sounds like a few people really need to (or must) get papers published.

Skeptical Scalpel said...

Regions, no doubt that had something to do with these two studies. It's hard to believe that they appeared in such prestigious journals.

Anonymous said...

I read with interest your comments relating to the paper 'Cheating experience...' which I have since sourced and read myself. I find your initial comments rather trivial, and perhaps displaying a lack of understanding for what the authors and their work was intending to do. On further exploration it appears that this group of researchers have published a number of articles on this topic (gaze behaviours of surgeons) in a number of surgery journals.

Regarding the second paper that you comment upon, I personally welcome the attempts of these researchers to examine underlying cognitive and neurological function. I found their paper interesting and informative, if not a little complex, but it isn't their fault if the reader cannot understand their work!

I have copied these comments in an email to the corresponding authors of both papers, perhaps they will have an input.

Skeptical Scalpel said...

Thanks for you opinion. We will see.

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