Biomedical Expert on Regulatory Parellels of Pelvic Mesh to Breast Implants, Federal Preemption and There's No Medical Grade Mesh

Jane Akre
January 13, 2016
William A. Hyman Biomedical expert
William A. Hyman Biomedical expert

MND, January 13, 2016 ~ Dr. William A. Hyman, a Biomedical expert has been brought in as a consultant in some pelvic mesh cases.

Dr. Hyman compares FDA's reclassification of POP (pelvic organ prolapse) mesh to class III as a parallel to breast implant reclassification.  It forced them off the market, but they came back after anecdotal data, he says.

The Food and Drug Administration (FDA) has given POP mesh manufacturers 30 months to submit proof of safety and efficacy to satisfy the more stringent PMA (premarket approval) which is required under class III designation of a medical device.

Silicone-filled breast implants were also reclassified by the FDA from class II to class III in 1988. By 1991, the FDA required a premarket approval (PMA) for silicone gel-filled breast implants.  None of the PMA's submitted contained sufficient date to support approval.  By 2013, the FDA approved both Allergan and Mentor's PMA for silicone gel-filled breast implants pending post-approval studies.

William A. Hyman, Texas A & M Biomedical Engineering for 39 years retiring as Professor Emeritus in 2011 before returning to New York.  Dr. Hyman (ME'65) went from Cooper to Columbia for his ME and ScD, and then to MIT for a post doctorate degree.  His professional activities also include medical device design and system safety, human factors, FDA regulation of medical devices, and clinical engineering.

Dr. Hyman writes in July 2014, Maybe That Wasn’t Such a Good Idea (Biomedical Safety & Standards), citing two recent examples that illustrate how technology sometimes gets ahead of knowledge giving the example of a renal denervation systems sold as a treatment for high blood pressure (though not sold in the U.S.) and the laparoscopic power morcellator.

He writes in Biocompatibility of Breathing Tubes Raises Interesting Questions that biocompatibility is crucial for implants, referring to ventilators specifically breathing tubes that come in contact with the body before it enters the lungs.  Are all polymers the same?  That answer has broad implications in ongoing mesh litigation. Is one polymer is the same or different from another polymer with the same name despite the addition of additives and plasticizers as well as post-manufacturing residuals?

He believes polypropylene mesh used for implants introduces a myriad of problems not limited to a lack of inertness. The tissues in the pelvis respond to the implant, even on a mechanical level. One mechanical property i.e., the polymer mesh, against the tissue of the body represents two different mechanical properties. “Something is going to happen.”

He cites porosity issue of the mesh, the body’s response to mesh and the bacterial response to mesh.   Also he’d like to make a distinction between the material and what you make out of that material. If you make a different products with different characteristics you get a different response.

Prolene Mesh
Prolene Mesh

“Just calling it polypropylene doesn’t tell you enough.  You did you get it from, the chemical structure and what else is in there?”

Q: On Quality Control- is there any consistency?

"No some manufacturers are buying it from people who didn’t know what they were doing despite the contrary disclaimers, that is, dummy sources. Consider, quality control issue from a single material supplier. If their purpose is carpet-backing their quality control requirements are way below that for an implanted medical device.  There is no term for medical grade polypropylene!”

"What’s supposed to happen is there is supposed to be qualified in the application form of the product. The FDA has been loose in accepting claims of biocompatibility on a broad basis. And that is only rarely brought up by the FDA.  For example the ventilator breathing tubes. I wrote basically knowing the chemical name doesn’t tell you much and certainly not enough.  The manufacturer is supposed to qualify the appropriateness of material choices for the product, but that hasn’t happened.

"Even if you had the identical polypropylene, if you make something with different mesh characteristics - mechanics and edge design - you get different performances. How it goes in also matters.   It’s not just the material but it procedure was sold as easy to do. I’ve worried about that. Does “easy to do” encourage a certain attraction to a “novel and new” approach suppress the evidence?  There are some elements of a human’s ability that’s part of the design and use challenge.  We can’t identify who they are.

"The manufacturers like to blame the patient in part because they are fat, diabetic and they smoke.  None is reflected in the contraindications. Either it’s for or not for the broad population."

Riegel v, Medtronic Inc.  – A U.S. Supreme Court decision says consumers who are injured by a defective medical device that received FDA approval, are preempted (prevented) from suing. The manufacturer enjoys immunity under this Supreme Court ruling. The late Charles Riegel and his wife, Donna Riegel bought suit against Medtronic after a catheter ruptured in Charles Riegel’s coronary artery during surgery.  The catheter is class III device that received FDA premarket approval. They alleged the device was defective. Federal court held that clearance by the FDA pre-empted common-law litigation.  

Q: On POP mesh reclassification, you  say it opens the door to federal preemption?

“The PMA (premarket approval) route is expensive. In theory with different classes of medical devices we can discern how much scrutiny is needed to assume safety. Whether anyone will bring forward for approval mesh under class III remains to be seen.  If they do, they are exempt from product liability.  The decision is the cost and effort versus protection after you do bring it to market."

"Take breast implants, for example, the manufacturers tried to bring in the past history as supportive but the FDA said a real study has to be done prospectively.  I’m assuming the FDA is serious; getting a PMA approved with existing data should not happen because it is not from a controlled study. It’s purely a few papers here and there and complaint-based.  They have to do prospective studies. How big they would have to be remains to be seen.  The problem is if you don’t have a good registry of who has your product and who put it in, there is a lack of control. You are hard-pressed to collect post market data.

"If you are going to do a study, you want your best result, you are going to choose the top tier of doctors. You might want to walk away from your own patient population and start over with a better controlled implant procedure."

Q: Let's talk about the biocompatibility issues that seem to incite different responses from different patients, including hernia mesh reactions.  

"The FDA has been weak on biocompatibility testing in the class II arena. See the standard draft for 10993,  it's a screening standard. That’s what the manufacturers cite on the material end. It’s been shown to pass a specific battery of tests.  There is no such thing as biocompatible material.  Your product may not work in another part of the body. 10993 becomes a screening tool which says you have to have shown at least your material has been qualified under a set of tests.  People got away with saying this is polymer x-y-z and others have used it with good results." #


AAMIBlog, January 30, 2015,  William Hyman: Biocompatibility of Breathing Tubes Raises Interesting Questions

Medical Device and Diagnostic Industry, April 9, 2014, Are These Medical Devices Too Dangerous?

ISO-10993 International Standard for Biocompatibility, April 23, 2013

FDA developed this guidance to assist industry in preparing Premarket Applications (PMA).

Maybe That Wasn't Such a Good Idea, Biomedical Safety and Standards, July 1, 2014

Riegel v, Medtronics. Read more here:

Injuryboard National News Desk on Medtronic, by Jane Akre, March 8, 2010

Regulatory History of Breast implants in the US, reclassified to class III in 1988 requiring premarket approval.  

By 1991 FDA required PMA for silicone gel-filled breast implants. None of the PMAs contained sufficient data to support approval. By 2013, the FDA approved both Allergan and Mentor’s PMA for silicone gel-filled breast implants pending post-approval studies.

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