Above are the results and conclusion from an abstract of a paper called "Single-Incision Laparoscopic Cholecystectomy: Will It Succeed as the Future Leading Technique for Gallbladder Removal?" It appears online in the journal Surgical Laparoscopy, Endoscopy & Percutaneous Techniques.
It is another great example of why you need to read the entire paper and not just the abstract.
The methods section says that the study involved 875 patients with prospectively collected data. Don’t be fooled by prospectively collected data. This research is retrospective.
Here are some issues.
How were patients selected to have single-incision (SILC) or standard 4-port (LC) laparoscopic cholecystectomy? They certainly were not randomized or it would have been mentioned. The easier cases were chosen for SILC. How do I know that? Well, 17.4% of the SILC patients had acute inflammation of the gallbladder compared to 35.5% of the LC patients. The statistical significance of this was omitted from the abstract, but the chi square p value is 0.0001.
Also not mentioned in the abstract was that 82% of the SILC patients had elective surgery compared to only 57.2% of the LC group, p <0 .001.
I have talked about the statistical trick of using a “straw man” before. [Type straw man in the search field to your right on this blog site.] A straw man occurs when researchers set up an artificial control and the find better results with their intervention.
The straw man in this case is the average operative time of the LC patients, 79 minutes which is significantly longer than the 71 minutes it took to perform SILC. The problem is that as shown in many other studies, standard LC can usually be done in 40 to 45 minutes.
If you look at some of my other posts on this subject, you will see that a straw man is particularly likely to appear in papers about SILC.
Will SILC succeed as the future leading technique for gallbladder removal? Maybe, but we are certainly going to need to see better evidence than this.