Hernia repair patients used as experimental subjects to evaluate new meshes

[gregd]

Im one of the patients who had a dextile mesh fitted.

[Good intentions]

Thank you Mark T. for reading through the full paper and sharing what you found. It’s surprising that there is so little analysis of the physical differences between the two products. The reason that one product might be better than another product. It’s brand name versus brand name. One company’s stuff competing with another company’s stuff, and they are essentially identical. Marketing and price point make the sale.

This seems to be the only difference that they could distinguish. And it looks like pure marketing hype. They just repeated what they read from the brochure.

“conforms even more to the contours of the groin region in comparison to other 3D meshes”

[MarkT]

The purpose of the study was to (retrospectively) compare outcomes between the Bard and Dextile meshes.

The background section talks about some ideas and research about mesh and the potential reasons behind complications of pain and recurrence (incl. inflammatory response, light-weight vs. heavy-weight, flat vs. 3d shape, and fixation vs. non-fixation). They point to a systematic review finding no improvement on chronic pain or foreign-body sensation with light-weight mesh, but increased recurrence rates. Also, that flat mesh is more likely to fold or migrate, and that fixation efforts to reduce that problem can result in more chronic pain. Avoiding fixation with 3D anatomically shaped heavyweight mesh has been identified as a ‘safe and effective’ solution.

They don’t explicitly talk about the decision process behind the hospital switching meshes (which would be nice to know, but isn’t the purpose of this paper), only stating the following:

“The hospital where the current study was conducted has switched from the 3DMax mesh (Bard) to a relatively new 3D mesh, the Dextile Anatomical mesh (Medtronic) since July 2020 for all laparoscopic hernia repairs. This new mesh has a 3D patented anatomical shape and conforms even more to the contours of the groin region in comparison to other 3D meshes. It is made of non-absorbable macroporous monofilament polypropylene textile and is heavyweight. The shape allows wider coverage of the hernia defects and potentially further reduces the risk of hernia recurrence.”

On their attempts to distinguish between reasons for recurrences so that mesh isn’t implicated as the sole/main reason in all of them: “The 2-year recurrences in the 3DMax Mesh group and the Dextile Anatomical Mesh group were due to a lipoma in 8.0% and 13.6%, due to a “true” recurrent hernia in 72.0% and 68.2% and unknown (e.g., when only physical examination was done) in 20.0% and 18.2%, respectively”.

I’m not quite sure how they distinguished between “true” recurrences and those due to “unknown” reasons…and it is unclear to me if those are mutually exclusive categories or if some proportion of the “unknown” are actually “true” (however “true” is defined)?

So we have a product for which this one study found no real clinical utility: “Even though the surgeons who used the Dextile Anatomical mesh were satisfied with the features and handling of the new product, the results of this study suggest that there were no substantial clinical advantages over the 3DMax mesh with regard to the studied outcomes.”

If there is a silver lining, at least a study with non-significant findings did not get buried (which was too common in the past)…and if I can be idealistic for a moment, we can hope that this helps to shift attention away from mesh shape and towards other reasons behind the troubling recurrence and pain rates we continue to observe…i.e., maybe we are seeing a plateau with how mesh product design can address these issues…?

As with most studies, I would love to see longer-term follow up data…as noted, those recurrence and pain rates are surely understated with only a 2yr post-op timeline passively relying upon patient reports.

[Good intentions]

Just to round the thread out, here are the two product pages, and the MAUDE database link. Put Dextile in the brand name on the MAUDE page and you’ll see that it is now in a race with 3D Max (type 3DMax as one word to see MAUDE results). More market share = more reports and more lawsuits.

https://www.medtronic.com/covidien/en-us/products/hernia-repair/dextile-anatomical-mesh.html

https://www.bd.com/en-us/products-and-solutions/products/product-families/3dmax-mesh#overview

https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfmaude/search.cfm

[Good intentions]

Thank you Mark T.

So it looks like one of those purchasing department decisions, maybe because the new product came in at a low price to get some market share. Was there a statement or two at the beginning describing what, exactly, the purpose of the study was, and why it was undertaken? “Hey, Purchasing changed our mesh, let’s compare it to the old stuff” seems like the only reason. Besides being the “first” to compare the new 3D product to 3D Max.

Disturbing also, as usual, to see the rationalizing used to try to show that the mesh is not the cause of any problems. Objectivity is hard. Not real recurrences, the surgeon’s weren’t skilled… If they are going to report “not all” they should report the actual number. If they don’t have it then they don’t know.

” As described in the results section, not all recurrences were “true” recurrences but also lipomas, although these lipomas may have formed in the interim, others have described recurrences due to missed lipomas [23]. This would suggest that these particular recurrences are not necessarily related to the mesh but to the technical execution of the surgery.”

And they describe major flaws in the study. But publish anyway. And, indirectly promote the idea that lap mesh has low pain rates, by including the percentages in the discussion. Hernia Journal does not seem to be a scientific journal at all. More of a hernia repair promotion magazine. Supposedly peer-reviewed but it doesn’t really seem that way.

The Journal is also associated with the EHS.

https://www.springer.com/journal/10029/aims-and-scope

“Hernia is a rigorously peer reviewed journal that regularly publishes specific topical issues and collections in addition to original articles, and is affiliated with the European Hernia Society (EHS), with the Asia-Pacific Hernia Society (APHS), and with the American Hernia Society (AHS).
…”
.
.
Not a good sign for progress. Just reporting that a new product is just as bad as an old product.

[MarkT]

I suppose I could also summarize the discussion points instead of copy-paste if that is a copyright issue…I was feeling lazy, and it won’t let me edit the post anymore :/

[MarkT]

This is a retrospective study, not a randomized control trial. Patients just gave the standard informed consent that covered future use of their data.

Also, there was no choice in what mesh was received because the “hospital where the current study was conducted has switched from the 3DMax mesh (Bard) to a relatively new 3D mesh, the Dextile Anatomical mesh (Medtronic) since July 2020 for all laparoscopic hernia repairs”.

Given that the study covered all repairs (with some exclusions) done between Jan. 2019 to Jan. 2022, it seems that which mesh each patient received simply depended upon their surgery date.

No statistically significant differences in ‘long-term’ outcomes:

Chronic pain 1yr out: 3.4% (Dextile) vs. 3.0% (Bard)
Recurrence within 1yr: 3.8% (Dextile) vs. 3.0% (Bard)
Recurrence-free probability after two years: ~94% (Dextile) vs. ~97% (Bard)

Some discussion:

“Despite the fact that the anatomical shape of the Dextile Anatomical mesh potentially allows wider coverage of the hernia defects and thus potentially lowers the recurrence rate, this was not found to be the case in this study. When the Dextile Anatomical meshes were first used, several early recurrences were seen after using the small mesh (13?×?9 cm). Therefore, the standard policy was changed to using the medium mesh (15?×?10 cm), which was also the standard policy during the current study period. Overall, the Dextile Anatomical mesh had a low hernia recurrence rate but did not differ significantly from the 3DMax mesh. As described in the results section, not all recurrences were “true” recurrences but also lipomas, although these lipomas may have formed in the interim, others have described recurrences due to missed lipomas [23]. This would suggest that these particular recurrences are not necessarily related to the mesh but to the technical execution of the surgery.
…
Another reason for the development of an anatomical three-dimensional hernia mesh was the assumption that this could reduce the risk on early- and chronic post-operative inguinal pain. This is thought to be the result of to the mesh adapting to the contours of the inguinal region and avoiding the need for mesh fixation, thereby minimizing injury to nerves. The present study confirms the previous reported low chronic post-operative inguinal pain rates in laparoscopic inguinal hernia repair using a three-dimensional hernia mesh [18, 19]. However, no significant difference was found in early post-operative pain at 8 weeks or chronic post-operative groin pain between the Dextile Anatomical mesh and the 3DMax mesh.

Even though the surgeons who used the Dextile Anatomical mesh were satisfied with the features and handling of the new product, the results of this study suggest that there were no substantial clinical advantages over the 3DMax mesh with regard to the studied outcomes.
…
One limitation is that only one follow-up at 8 weeks post-operative was conducted. Previous studies with telephone contact showed that most recurrent hernias are referred by general practitioners. All patients were instructed to report when they had reappearing symptoms. However, late recurrences may have been missed since not all the patients were investigated after 1 year. In addition, there was no randomization of patients due to the retrospective design of this study, which may have led to selection bias”.

It is worth noting that the purpose was to compare the two meshes over the shorter-term…but the limitations they mention are important, because they suggest that the pain and recurrence rates may be understated (IMHO, they surely are).

They only pro-actively followed-up once with patients 8-weeks afterwards and then just told patients to contact them with subsequent problems. So the longer-term chronic pain (pain > three months) and recurrence data relied upon patients contacting the hospital. Further, we know that 2yrs is an insufficient follow-up period to accurately measure chronic pain and recurrence. Their own graphic shows a number of recurrences being reported near the tail-end of the 2yr period and there is no reason to believe that suddenly drops off to zero.