Avendt v. Covidien Inc. (262 F. Supp. 3d 493, 2017)

OPINION AND ORDER (1) EXCLUDING CERTAIN TESTIMONY OF PLAINTIFF ROBERT AVENDT’S TREATING PHYSICIAN; (2) GRANTING DEFENDANT’S MOTION FOR SUMMARY JUDGMENT (ECF NO. 116); (3) DENYING PLAINTIFFS’ MOTION FOR PARTIAL SUMMARY JUDGMENT (109); (4) DENYING AS MOOT DEFENDANT’S MOTION TO EXCLUDE TESTIMONY OF DAVID ANCELL (ECF NO. 110); (5) DENYING AS MOOT DEFENDANT’S MOTION TO EXCLUDE TESTIMONY OF DAVID HAMMEL (ECF NO. 113) AND (6) DISMISSING PLAINTIFFS’ COMPLAINT WITH PREJUDICE

PAUL D. BORMAN, UNITED STATES DISTRICT JUDGE

This is a product liability action involving Plaintiffs’ claim that Defendant Covidien Inc. (“Covidien”) failed to appropriately test, and therefore failed to adequately warn practicing physicians about the side effects of, a hernia repair mesh product that was used to repair Robert Avendt’s recurrent hernia. Plaintiffs theorize that Covidieris hernia mesh product caused Mr. Avendt to have a chronic non-healing wound that became infected and required further surgery. Covidien has moved to limit the testimony of Plaintiffs’ only medical expert, Mr. Avendt’s treating physician, and for summary judgment on Plaintiffs’ claims. The Court has received extensive briefing from the parties on Covidieris motions and conducted two lengthy hearings, as discussed below. For the reasons that follow, the Court GRANTS Covidieris motion for summary judgment.

INTRODUCTION

This action involves Plaintiffs’ claim that Covidieris biological surgical mesh product (“Permacol”), an FDA approved medical device which was implanted in Plaintiff Robert Avendt on December 17, 2008 to repair a third recurrent hernia, was not adequately tested before being released to market and therefore Covidien failed to adequately warn practicing surgeons of Permacol’s propensity to fail due to its cross-linked design. Plaintiffs claim that had Covidien performed “an adequate clinical trial” on Permacol, and included the results of such a study in the Permacol instructions for use, the surgeon who placed the Permacol mesh in Mr. Avendt would not have chosen the Permacol cross-linked biologic mesh to repair Mr. Avendt’s third recurrent hernia, and/or would not have left the Permacol in Mr. Avendt’s abdomen after detecting a sero-ma, and Mr. Avendt would not have suffered the infected, chronic non-healing wound that allegedly caused his injuries.

I. PROCEDURAL BACKGROUND

On April 19, 2016, the Court issued an Opinion and Order in this case, Avendt v. Covidien, 314 F.R.D. 547 (E.D. Mich. 2016), partially granting Defendant’s motion to limit the opinions and testimony of Plaintiff Robert Avendt’s treating physician, Michael J. Rosen. The Court determined, after conducting an extensive hearing on Covidien’s motion to limit Dr. Rosen’s testimony, that it could resolve some but not all of Covidien’s challenges to Dr. Rosen’s proposed testimony. In summary, the Court determined that Dr. Rosen was required to file a full-blown Fed. R. Civ. P. 26(a)(2)(B) Report with respect to certain of the opinions that Plaintiffs seek to have him offer and that the Fed. R. Civ. P. 26(a)(2)(C) Disclosure that Plaintiffs filed on behalf of Dr. Ro-sen, see ECF No. 159-7, Pis.’ Resp. to Mot. to Exclude Rosen, Ex. G, Plaintiffs’ Fed. R. Civ. P. 26(a)(2)(C) Supplemental Disclosure, was insufficient under the Federal Rules of Civil Procedure as to certain of his proposed opinions. Avendt, 314 F.R.D. at 556-57 (observing the Federal Rules of Civil Procedure Rules and

Commentary, which notes that “there is no reason to conclude that Rule 26(a)(2)(C) was intended to allow treating physicians to give expert opinions that go beyond the scope of treatment and diagnosis without having to prepare a report with respect to those further opinions ... It is not sufficient for the summary disclosures to mention that the treating physician is going to offer these additional expert opinions”). The Court concluded:

Thus, the substance of a treating physician’s testimony, and not his or her status as a treating physician, determine whether a Rule 26(a)(2)(C) disclosure will suffice. In making this call, the distinction made in pre-2010 case law, between treating physicians who opine only matters relating to their treatment and diagnosis on the one hand and treating physicians who offer opinions that fall outside the scope of the treating relationship on the other, continues to be determinative.

314 F.R.D. at 557 (collecting cases).

The Court thus concluded that Dr. Ro-sen, who did not file a Rule 26(a)(2)(B) expert report in this case, would be limited to testifying as a treating physician and therefore limited to those opinions that were formed for purposes of, and within the scope of, his care and treatment of Mr. Avendt. The Court determined that certain of Dr. Rosen’s opinions proposed in Plaintiffs’ Rule 26(a)(2)(C) disclosure fell well outside any possible relation to his care and treatment of Mr. Avendt and would be excluded, including Dr. Rosen’s proffered opinion that “there is clearly a need for further animal and human trials investigating how varied clinical settings affect the performance of different xenograft biologic meshes.” 314 F.R.D. at 560 (finding that Plaintiffs’ Rule 26(a)(2)(C) treating physician disclosure was insufficient and a full blown expert report was required with regard to the opinions proffered in paragraphs three, four, and five of Plaintiffs’ Rule 26(a)(2)(C) disclosure).

■With regard to other aspects of Dr. Ro-sen’s proposed testimony as set forth in Plaintiffs’ Rule 26(a)(2)(C) disclosure; Plaintiffs disclosed that Dr. Rosen would testify .regarding certain matters about which Dr. Rosen clearly lacks expertise, as Covidien established in Dr. Rosen’s deposition. The Court concluded that Dr. Rosen’s “proposed” opinions on such matters, even if Plaintiffs could have established that Dr. Rosen, formed them within the scope of his care .and treatment of the Mr.. Avendt, were well beyond his admitted area of expertise, and were excluded under Dau-bert without necessity of further testimony at a Daubert hearing:

[Dr. Rosen] lacks sufficient expertise to opine on the topics of the material science of cross-linking, immunogenic response to cross-linked material or the scientific' process related to the fatigue and breakdown of mesh. Similarly unsupported are any opinions relating specifically to the design and testing of Permacol. The Defendant’s motion to strike all such opinions is GRANTED ’without need of a Daubert hearing,

314 F.R.D. at 562.

As to other aspects of Covidien’s challenge to Dr. Rosen’s testimony, the Court concluded that it lacked sufficient information and ordered that Dr. Rosen appear for a Daubert hearing. Due to Dr. Rosen’s busy schedule and limited availability to appear as the Court ordered, the Daubert hearing did not take, place until January 26, 2017. Following the Daubert hearing, the Court ordered the parties to submit a round of supplemental briefing on the admissibility of Dr. Rosen’s opinions. Those supplemental briefs were submitted' in March, 2017. (ECF Nos. 231, 232, 233.)

II. FACTUAL BACKGROUND

A. Plaintiff Robert Avendt’s Treatment With Dr. Ash

Mr. Avendt began treating with Dr. Christopher J. Ash, D.O. in August, 2005, weighing approximately 280 pounds and presenting with complaints of a large ventral hernia. (ECF No. 116, Def.’s Mot. Summ. J. Ex. A, Treatment Notes of Dr. Christopher J. Ash, D.O.) Mr. Avendt was then 54 years old and a Type-2 diabetic with “multiple comorbidities,” high cholesterol, hypertension and a history of abdominal surgeries that began in 1997 with a Hartmann procedure for diverticulitis. (Id.) In 1998, Mr. Avendt had'an emergency hernia repair related to an incarcerated ventral hernia, followed by a small bowel resection and primary repair of the ventral hernia. (Id.)

After consultation with Dr. Ash in 2005, Mr. Avendt decided to continue his efforts at weight loss and postpone any surgical repair of his hernia. (Id.) Mr. Avendt’s hernia went untreated until June, 2008, when Mr. Avendt returned' to Dr. Ash, having lost approximately 30 pounds, and seeking to have his abdominal hernia repaired. (Id.) On August 21, 2008, Dr. Ash repaired Mr. Avendt’s recurrent hernia and implanted a large 25 cm x 25 cm Parietex synthetic surgical mesh. (Defi’s Mot. Summ. J. Ex. B, 8/21/08 Operative Note.)'

Mr. Avendt 'had worsening abdominal pain following his August 21, 2008 surgery and his hernia recurred. On December 17, 2008, Dr. Ash performed another hernia repair. (Def.’s Mot. Summ. J. Ex. C, 12/17/08 Operative Note.) While Mr. Avendt’s August, 2008 hernia repair had been done laproscopically, the December, 2008 surgery to repair the recurrence.had to be “more invasive” and required a larger incision. (Def.’s Mot. Summ. J. Ex. D, July 11, 2012 Deposition of Christopher Ash 13:21-14:4.) Dr. Ash discovered that the Parietex mesh that he had previously placed in the first repair had “come loose,” and “folded transversely” onto itself in the mid-portion of Mr. Avendt’s abdomen. (Ash Dep. 75:10-25; 12/17/08 Operative Note.) Dr. Ash removed the entire Parie-tex mesh, and had to dissect free some portions of the bowel that had adhered to the mesh. (12/17/08 Operative Note.)

In the course of the 12/17/08 surgery, Dr. Ash had “an issue in relation to some scar tissue and [Mr. Avendt’s] bowels' being up into his hernia.” (Ash Dep. 14:7-8.) “[I]n doing the dissection [they] had some serosal injury to some of the small intestines and to some of the large intestine.” (Id. at 14:5-6.) Dr; Ash testified that this injury created a “clean contaminated wound,” which meant that Dr. Ash “cut into the surface of the bowel and bacteria could have escaped,” but no excrement was visible. {Id. 24:21-25:3, 61:5-14.) Because of the involvement of the injury to the bowel, and the potential for contamination, Dr. Ash choose to úse a Permacol biological mesh (rather than a synthetic mesh such as the Parietex that he removed) because he was “uncomfortable putting a plastic prosthetic into [Mr. Avendt’s] abdominal cavity for risk of infection.” (Id. at 14:8-12; 24:11-24.) Going into the December surgery, Dr. Ash had “intended to use ⅞ synthetic mesh,” and had it not been for the “worry of infection,” Dr, Ash “probably never would have put a biologic” in Mr. Avendt. (Id. at 61:5, 62:16-63:15.)

Dr. Ash had performed many surgeries with biological mesh but this was the first time he had used the Permacol biological mesh. (Id. at 14:13-14; 15:1-5.) Dr. Ash was “apprehensive” because of his lack of experience with the Permacol product. (Id. at 14:19.) But Permacol “fit the bill” because it was known to be “more resistant to infection” and tended “to fix better.” (Id. at 15:18-21.) The Permacol sales representative was present in the operating room and provided the Permacol mesh to Dr. Ash. (Id. at 15:24-16:11.) The decision to use Permacol was completely Dr. Ash’s decision. Dr. Ash testified that the Covi-dien representative, “Matt Aris would never make that decision.” (Id. at 34:1-6.) Dr. Ash may have read some promotional literature about Permacol but had never discussed Permacol with any of the product representatives prior to using it on Mr. Avendt. (Id. at 25:13-21.) Dr. Ash fully understood the advantage of the Permacol mesh and explained why he consciously chose to place the Permacol in Mr. Avendt’s wound:

Q: Can you explain the benefits of using the Permacol in Mr. Avendt’s case at the time?

# * *

A: Alternatives to prosthetic meshes are one of two things, either .you maintain a hernia or try to close it primarily, which in this case was just not physically possible, or you use a biologic. The only biologic available and the only one that we had experience or I had experience with prior was an Alloderm product. And we had plagued recurrences with it, turns out it’s a little too flexible to fix the holes. So this biologic mesh product is, and biologic products in general, are more resistant to infection and tend to fix better and more of a clean contaminated type of situation. And this Perma-col fit the bill.

(Ash Dep. 15:6-7, 11-21.) Prior to using the Permacol mesh on Mr. Avendt, Dr. Ash may have read a “brochure from Covi-dien” or “looked at some throw away material,” but had not “met with the rep or had any formal education,” reviewed the product literature or read any peer-reviewed materials about the Permacol product. (Id. at 25:7-26:11.) Nonetheless, Dr. Ash felt that he was well educated and informed on the use of biologies and qualified to use a product such as Permacol during a case if needed. (Id. at 61:21-62:2.) Dr. Ash intentionally chose Permacol because the previous biologic he had used was performing poorly and resulting in multiple hernia recurrences and he knew Permacol to be a more durable product and a “remarkably better choice” than doing nothing to repair Mr. Avendt’s hernia. (Id. at 24:15-24.) Post-operatively Mr. Avendt’s condition was pretty typical and when he did first present with a wound secreting liquid, Dr. Ash suspected an infection but the liquid “didn’t grow back any bugs in culture” and so an infection was not present. (Id. at 36:12-14.)

The Permacol mesh comes out of its sterile packaging with a strong “cat urine smell,” and required an extensive 10-15 minute “soaking” process to prepare the mesh for implantation. (Id. at 32:19-33:6, 33:12-25, 34:7-15.) Dr. Ash did not specifically discuss with Mr. Avendt in advance of the December, 2008 surgery the specific “type” of mesh, i.e. synthetic or biologic, he was planning to use to do that repair because he believed the risks of both were “essentially the same.” (Id. at 59:20-60:18.)

Following the December, 2008 surgery, Mr. Avendt was having increasing redness, swelling, pain and abdominal fluid collection. On May 18, 2009, Dr. Ash saw Mr. Avendt and suspected that he had developed a seroma (a collection of fluid anteri- or to Permacol mesh and peritoneum) that may have become infected. (Def.’s Mot. Summ. J. Ex. K, May 18, 2009 Letter from Dr. Ash to Dr. Daros.) Dr. Ash operated the next day, on May 19, 2009, to drain and debride the abdominal wall seroma. (Def.’s Mot. Summ. J. Ex. A, Treatment Notes; Def.’s Mot. Summ. J. Ex. L, 5/19/09 Operative Note.) Dr. Ash observed the Permacol mesh, which “appeared intact,” but on closer examination after irrigating the wound and manipulating the mesh, it was found to be “quite brittle” and appeared to have some “cracks and holes.” (5/19/09 Operative Note.) Dr. Ash opted to “stitch” the Permacol mesh and leave it in rather than remove the mesh altogether. (Ash Dep. 70:16-71:5.) Cultures taken from Mr. Avendt’s wound after the May, 2009 drainage and repair did not show any sign of infection. (Id. at 69:2-22.)

Mr. Avendt continued having “difficult, chronic” problems with wound healing, drainage from the wound and ultimately “odd material,” later determined by Dr. Ash to be pieces of the Permacol mesh, began coming out of Mr. Avendt’s wound. (Ash Dep. 18:20-19:22.) The expelled material varied in size from half-dollar to small flecks. (Id. at 37:15-21.) At no time did cultures taken by Dr. Ash come back positive for infection. (Id. at 36:14-15; 51:7-25; 69:2-22.)

Sometime after the May, 2009 operation, but before referring Mr. Avendt to Dr. Rosen, Dr. Ash presented Mr. Avendt’s case at an Abdominal Wall Reconstruction Conference in Washington, D.C. (Ash Dep. 38:5-11.) Representatives from Covidien were present, and Dr. Rosen was a member of the open-mike panel. Dr. Ash said he got at least “five different opinions” from this panel of experts about how to proceed. (Id. at 38:15 — 40:12.) The Covidien representative asked Dr. Ash to send him more information on Mr. Avendt’s case but Dr. Ash never did provide the information because the Covidien sales representative, Matt Aris, who provided Dr. Ash with the Permacol for the - 2008 surgery,. “had already been given all the information.” (Ash Dep. 41:3-16, 73:22-74:25.)

Dr. Ash recorded, in a July, 2009 clinic note, that he had “vetted” Mr. Avendt’s case with multiple specialists to discuss the proper course of treatment for Mr. Avendt:

07/13/09, Robert Avendt. He is in for follow up on his wound. We have vetted his operation with multiple specialists at multiple different conferences over the last -month and the prevailing thought processes consist of two choices. One is that we take him back and clean out this area of the remaining Permacol, do a temporary closure versus a separation of components and primary closure. The second idea is to let him finish the Per-macol expulsion which I believe he is close to doing, let the wounds close up and make a plan to move ahead with a primary repair with separation components and mesh placement of nonbiological nature.

(EOF No. 117, Sealed' Exhibit 1 to Def.’s Mot. Summ. Judg., Ash Treatment Notes PgID 4220.) Ultimately, Dr. Ash elected to go with the second “consensus” option and decided to let the process of Mr. Avendt “expelling this biological mesh from his wound” continue to work itself through. When Mr. Avendt’s hernia recurred again, Dr. Ash referred Mr. Avendt to Dr. Michael Rosen at Case Western, a leading national expert on hernia repair, “to fix [Mr. Avendt’s] recurrent recurrence.” (Def.’s Mot. Summ. J., Ex. A, Ash Treatment Notes PgID 4220; Ash Dep. 21:2-8, 35:10-25.)

B. Mr. Avendt’s Treatment With Dr. Rosen

1. Dr. Rosen’s deposition testimony.

Dr. Rosen, who wás at Case Western University Hospital at the time of Mr. Avendt’s surgery and is now at the Cleveland Clinic, is a specialist in hernia repair who has spoken, trained, practiced and published on the subjects of hernia repair and mesh, both synthetic and biologic. (Def.’s Mot. Summ. J. Ex. I, May 11, 2105 Deposition of Michael J. Rosen,. M.D. 11:11-13; 14:12-21, 37:1-25, 39:18-40:16.)

Eighty percent of Dr. Rosen’s- practice is hernia repairs. He uses both synthetic and biologic mesh but “favor[s] synthetic meshes for the vast majority of hernias” he performs. (Rosen Dep. 41:4-12.) At the time of his deposition, Dr. Rosen was the Principal Investigator of an FDA monitored study comparing synthetic and biologic mesh. (Id. at 41:15-18.) Outside of the trial study, he uses biologic mesh less than 2 percent of the'time. (Id. at 41:18-20.) He uses Strattice biologic mesh and has never used Permacol. (Id. at 41:21-25.) Dr. Ro-sen identified obesity and diabetes as factors that predispose a patient to develop an incisional hernia and to have complications with wound healing. (Id. at 43:22-44:2.) Dr. Rosen testified that the success of most hernia operations comes down to good wound healing. Poor wound healing can affect the recurrence of hernias — patients with poor wound healing will have an increased* incidence of recurrence. (Id. at 46:17-47:11.) Poorly controlled diabetes also increases the risk of recurrence of hernias due to the body’s inability to lay down good collagen to form scar tissue. (Id. at 49:2-16.) Also, the risk of re-recurrence increases with each recurrence — as much as 40-50% following a third repair. (Id. at 50:19-51:18.) “Once you.have a failed hernia, unless things change in some meaningful way, it’s a vicious cycle.” (Id. at 50:15-18.)

The Covidien synthetic mesh (not at issue in this case) is polyester and the BARD mesh is polypropylene. Dr. Rosen prefers polypropylene for open procedures. (Id. at 56:17-57:24.) For a biologic mesh, the Cleveland Clinic was using Per-macol but is switching over'to Strattice, which is a pigskin, non-cross-linked mesh. (Id. at 58:15-59:9.) Permacol biologic is also pigskin, but is cross-linked. Both have their selling points. (Id. at 60:23-61:13.) The processing of the pigskin biologies is “proprietary” and there is “very little” in the way of clinical trial information available. (Id,- at 60:15-22.) There is a lot of debate about which mesh is the best, and the ideal mesh has not been found, but “less than ideal meshes have been re.-vealed.” (Id. at 62:8-22.)

Dr. Rosen, reviewed the Permacol In-struotion-For-Use (“IFU”) document for a paper that he wrote and recalls that it contained a warning or . a contraindication in the presence of infection or contamination which he feels is not what a surgeon wants to hear when they are “reaching for a biologic mesh,” (Id. at 63:19-21; Def.’s Mot. Ex. E, IFU.) Dr. Rosen explained that use of the term “infected” is a bit misleading and prefers to refer to the CDC “crystal clear guidelines” for the four wound classes: Class I (clean), Class TI (clean-contaminated), Class III (contaminated) and, Class IV (dirty). (Id. at 70:1-5.)

All mesh on the market is approved for use |n a “clean” Class I wound for “reen-forcement where soft’tissue weakness exists,” and that is the Permacol IFU terminology. (Id. at-67:3-9.) When bacteria get on these materials, “there is a concern that collagenations in the bacteria can break down the mesh and' affect its long-term performance.”- (Id. at 67:9-13.) While every company would like to be able to market a mesh with- the indication for use in a contaminated field, “no company is going to take the risk of a randomized controlled trial that might disprove that their mesh is worthwhile and. spend millions of dollars.” (Id. at 68:23-69:2.) So, no mesh on the market is FDA “approved” for use in anything other than a Class I wound, but biologic mesh is “believed” to tolerate an infected environment better than a synthetic mesh.

As noted supra, Dr. Rosen has been the Principal Investigator, on trials, involving synthetic and biologic mesh products. (Id. at 41:15-18, 65:18-66:3.) In 2007 or, 2008, the FDA tried to start a trial, which Rosen reviewed, to remove infected mesh and replace it with Permacol but the consensus was that it would probably fail so the trial never got going. (Id. at 67:18-25.) Because such a trial was “beyond the scope of what the FDA requires,” companies decided not to take the business/financial risk of undertaking the trial. (Id. at 68:6-9.) At the time of his deposition, Dr. Rosen was involved in a randomized trial for Covidien comparing synthetic to biologic mesh in clean and clean contaminated wounds. (Id. at 70:4-11.) If in his practice he was faced with a patient with a Class II or III wound, he would have a conversation with the patient about the risks and benefits of both synthetic and biologic, explaining that the synthetic will have 'a lower recurrence rate but the biologic, although having a higher long term recurrence rate, “potentially can handle an infection better.” ■ (Id. at 71:6-25.)

While at Case Western University Hospital in 2007-2009, Dr, Rosen conducted basic science work in his lab on all different types of meshes to determine how they respond to presence of contamination. (Id. at 72:4-11.) The determinants are multi-factorial and include the size- of the pores, the weight of the material, the type of material but the studies “to date” (in 2015) indicate that “the larger pore synthetic materials are surprisingly resistant to infection.” (Id. at 73:7-9.) When you place a mesh into a contaminated field, “it basically becomes a race for ingrowth into the tissue or bacterial coating of the material and then infection, puss, biofilms,” (Id, at 73:17-22.) So, the quicker things “ingrow,” the more resistant the site'will be to bacterial colonization that propagates the infection. (Id. at 73:22-25.) In Dr. Rosen’s opinion, the best synthetic product for a contaminated wound would be á large pore polypropylene and the best biologic would be a “non-cross-linked porcine dermis,” (pigskin). (Id. at 74:18-75:4.) For patients who are very infection averse and more tolerant of a recurrence, he might suggest the biologic and for those who are averse to a recurrence but will risk the infection, he would suggest the large pore polypropylene synthetic. (Id. at 75:12-23.)

While Dr. Rosen has been involved in several clinical trials involving mesh products, he has not studied the underlying design of the product in terms of the methods, such as cross-linking, employed to produce the mesh. (Id. at 78:20-79:8.) Indeed, although Dr. Rosen testified that he doesn’t use Permacol because “he [doesn’t] like cross-linking,” Dr. Rosen could not explain the process - involved in cross-linking and could not identify the difference between the biologic mesh that he uses (Strattice) and the Permaeól biologic mesh other than the fact that the Strattice product is not cross-linked. (Id. at 83:8-84:1.) Nor does Dr. Rosen profess to have expertise in the area of human immune response to the various mesh materials, although he is aware of the data resulting from mostly animal-based studies. (Id. at 80:23-82:8.) His expertise is in the clinical aspects of the competing types of mesh, a- subject that is still very, much under study. He describes the current competing clinical observations as follows:

Q: So what do you tell your patients about the risks and .benefits , with your synthetic option versus your biologic option?

A: Well,. I think with the large pour [sic] polypropylene mesh, we talk about the fact that it tends to be .fairly durable, to .have a lower recurrence rate and in. our clinical experience up to date, it seems to .be fairly resistant to infection and will still incorporate in the face of infection. But the point of the study is that we’re trying to figure out if that’s actually true. *

The biologic mesh tends to be less durable long term, because you have to lay down your own scar tissues and things like that, so recurrence rates can be a little bit higher. But if you were to get an infection, it’s.often something we can treat through and don’t need to reoperate and it might dissolve and go away and you’d be left with a recurrence but not a chronic infection problem.

(Rosen Dep. at 86:18-87:13.)

Dr. Rosen did the initial portion of the procedure on Mr. Avendt on January 28, 2010. His role was to go in, “get down all the scar tissue, lice the bowel adhesions, remove as much of the infected mesh [sic] and then kind of leave a hole” where they were going to try to reconstruct the herniated area with just a flap, not using any other material or mesh, to try to cure his infection, which was a Class IV wound on the date of . surgery. (Id. at 98:17-99:12, 101:20-22.) Dr. Rosen completed his portion of the procedure and was followed immediately by Dr. Salgado, who took skin, fascia and muscle from Mr. Avendt’s thighs to create the flap for the abdominal repair. (Id. at 100:12-101:1.) Dr. Salgado placed drains at the surgical site and closed the wound. (Id. at 101:8-19.)

Six months following the surgery by Drs. Rosen and Salgado, Mr. Avendt had developed a recurrence of his hernia and an infection on his right leg where Dr. Salgado had removed the skin for the abdominal flap. Id. at 105:2-106:20. Mr. Avendt reported to Dr. Rosen on November 5, 2010, that his hernia was fairly asymptomatic but he was having a lot of weakness and pain in his leg and difficulty getting around. (Id. at 107:9-108:5.) Dr. Rosen opines that the hernia recurrence following the surgery performed by Dr. Rosen and Dr. Salgado was due to the fact that the “defect was so big after what had happened to him in the past and in the presence of a Class 4 wound” the ultimate goal was to get the wound to heal and accept a fairly high chance of a recurrence. (Id. at 113:18-25.)

Dr. Rosen recalls discussing generally with Mr. Avendt the issues about infection with hernia mesh repairs but did not tell Mr. Avendt that Permacol was a defective product and never wrote to the FDA or told anyone in his hospital that Mr. Avendt had a defective mesh. (Id. at 116:17-117:21.) Dr. Rosen did not recall whether he looked into the pathology of Mr. Avendt’s removed Permacol mesh or if he included Mr. Avendt’s case in any of his case studies. (Id. at 119:13-121:12.)

Dr.' Rosen is of the opinion that in 2009, Permacol was not a reasonably safe product for use based on the data then available which indicated that a cross-linked material would not behave like a biologic mesh and, in 2009, Dr. Rosen would not have chosen a cross-linked biologic material. (Id. at 127:19-25.) Although not “the scientist who vetted it,” Dr. Rosen opines that in looking at the Permacol mesh the problem was that “they decided to heavily cross-link that material” and consequently made it tougher to break down and more of a barrier to ingrowth. (Id. at 132:7-133:15.) Dr. Rosen opines that every company knows that their biologic mesh 90% of the time is being put in a Class II or III wound situation and even though the FDA does not require biologic mesh to specifically have clearance for use in Class II or III wound, a surgeon asking for a biologic mesh product would reasonably assume that the product was designed to perform in that wound class. (Id. at 142:11-144:22.) Dr. Rosen opines that if Mr. Avendt had received a non-cross-linked biologic mesh, he likely would have had a recurrence but it would have been in a clean field. (Id. at 148:12-149:2.) With a non-cross-linked mesh, the body would have cleared the infection and he would have had a recurrence that could have been repaired with a synthetic mesh. “But because of the size of the hernia, the complexity of the hernia and the active infection in a Class IV wound, that’s- when essentially all of his reconstructive options were burned due to the chronic, ongoing infection with the big hernia.” (Id. at 149:2-7.) Because the Per-macol mesh was cross-linked, “it behaved like a synthetic mesh and was unable to be cleared. That’s why it was an ongoing infection when I saw him.” (Id. at 149:18-21.)

Dr. Rosen is clear that he does not know, and does not profess to know, the scientific process by which the Permacol mesh is cross-linked and is not sure if he has ever even examined a Permacol mesh although he knows it smells like cat urine. He is not a material scientist or a biomedical engineer although he has collaborated with many such experts on his papers. (Id. at 151:24-152:18,164:4-165:10.) In essence, Dr. Rosen is of the opinion that Covidien knew that Permacol was being used in situations for which it was contraindicated, i.e. off label in Class II or III wounds, and should have studied whether it was safe in those off label applications. (Id. at 151:12-23.)

Dr. Rosen has written extensively about the clinical performance of cross-linked materials and testified that he supports his conclusions about the cause of Mr. Avendt’s damages by his observations during Mr. Avendt’s surgery of the Permacol mesh with puss sitting around it and based on his experience with cross-linked biologic mesh, which doesn’t go away due to its cross-linking and “just sits there” and doesn’t dissolve. (Id. at 154:7-155:16.) Dr. Rosen testified that he would use a Perma-col mesh only in a situation in which a synthetic mesh would be indicated, i.e. in a clean or Class I wound. (Id. at 157:1-11.) Dr. Rosen testified that at the Cleveland Clinic, 100% of the uses of biologic mesh is off-label, outside of its indication, because no mesh is indicated for use in a contaminated wound. Dr. Rosen would never elect to use a cross-linked mesh in such a situation. (Id. at 157:11-22.) His only criticism of the Permacol mesh is that it is cross-linked and in his clinical experience, he has never seen a mesh in sitting in puss outside of cross-linked material. (Id. at 167:19-24.) He has never taken care of a case of a non-cross-linked biologic mesh where he has had to go back in and remove an infected piece of mesh. The non-cross-linked biologic mesh will dissolve and clear in the face of infection and at most you are left with a recurrence. (Id. at 169:14-18.) Dr. Rosen has reviewed articles that indicate that other non-cross-linked biologic mesh products are safe in Class II and III wounds, but he has never seen such a statement regarding a Perma-col mesh. (Id. at 171:11-172:16.)

Dr. Rosen summarized his opinion that the cross-linking of the Permacol mesh caused Mr. Avendt’s injuries:

Q: So in terms of what was your methodology in coming to your conclusion of the case that it was the cross-linking that—

A: Sure. So my hypothesis was, he had a chronic draining sinus because there was a piece of foreign material in there, Permacol. So my observation was that the wound did not heal for a year. In my experience in maybe managing 2 to 3,000 of these cases, typically when wounds don’t heal, there’s some remaining foreign body that the body cannot clear.

So when we operated on him and performed the experiment, we drilled down and actually were able to observe and document unincorporated Permacol cross-linked mesh sitting in a bed of puss and granulation tissue due to ongoing nonhealing. And when we removed it all, you know, my conclusion, even in the setting of contamination, the wound healed. So to me that’s conclusive, that for one year the wound didn’t heal, you take out the one thing and everything heals from an infectious standpoint, to me, that’s pretty good scientific evidence that it’s conclusive.

(Rosen Dep. 174:17-175:16.)

When asked his understanding of his role in testifying in this matter, Dr. Rosen responded:

Q: Do you understand that you’re only designated as a treating doctor? Have you had any conversation with the plaintiffs lawyers about that?

A: I asked like what exactly my role is in this and I think they said I’m like a hybrid, so where I was the treating doctor and obviously I can provide expert testimony just because of my clinical experience.

Q: And that’s what you expect to do-at trial?

A: Sure.

Q: Your opinions about cross-linking were not formed because of Mr, Avendt; they were formed outside of that, correct?

A: Well, no, they were not formed exclusively because of him. They were formed because of my clinical experience in the lab and treating patients with complications related to cross-linked materials.

Q: Was that before 2009 or after 2009? A: I think it started before and has continued to date.

(Rosen Dep. 190:11-191:9.)

2. Dr. Rosen’s testimony at the Dau-bert hearing.

Dr. Rosen is of the opinion, and has expressed the view in written peer-reviewed publications, that Permacol is acceptable to use in a Class I wound although personally he prefers other “less expensive” and “more durable materials” that are available for use in a Class I wound. (ECF No. 222, Transcript of January 26, 2017 Daubert Hearing 10:11-19, 10:14-16.)

In. 2009, just prior to Mr. Avendt’s surgery, Dr, Rosen co-authored an article titled “Major- Complications Associated With Xenograft Biologic Mesh Implantation in Abdominal’Wall Reconstruction,” that was published in the peer-reviewed journal “Surgical Innovation.” (Daubert Tr. 19:21-23, 21:19-25; Joint Exhibit List Ex. 2, K.C. Harth, M.J. Rosen, “Major Complications Associated With Xenograft Biologic Mesh Implantation in Abdominal Wall Reconstruction,” Surgical Innovation (2009); 16(4):324 — 329 (Dec.).) This article analyzed data obtained from the Manufacturer and User Facility Device Experience (“MAUDE”) data base, which is maintained by the Food and Drug Administration ' (“FDA”) and collects voluntary electronic reporting that aims to capture adverse events' (“AEs”) related to medical devices approved by the FDA. (Joint Exhibit List Ex. 2, “Major Complications” at 325, PgID 6913.) In this article, Dr. Rosen and his colleagues conclude that: “Based on the available literature and the review of the FDA MAUDE database, it seems reasonable to conclude that cross-linked meshes seem to behave reasonably well in clean [Class I] and clean-contaminated [Class II] cases.” (Daubert Tr. 22:8-18; Joint Exhibit List, Ex. 2, “Major Complications” at 327, PgID 6915.) The article goes on to suggest that “the effect of cross-linking on infected and contaminated ventral hernia repair remains largely unknown at‘this time and requires careful evaluation.” (Daubert Tr. 22:19-23; “Major Complications” at 327, PgID 6915.)

Dr. Rosen explained at the Daubert hearing that these comments regarding the cross-linked meshes performing “reasonably well” in, clean and clean-contaminated cases, has to be read in the context of how little overall published literature there was at that time on the performance of cross-linked meshes due to the very small number of clinical trials with very poor follow up. (Daubert. Tr. 99:4-13.) Dr. Rosen testified that his overall conclusion based- on this MAUDE database article was that it was “a strong signal" that there were “safety ■ issues” with these cross-linked meshes that required “careful and further evaluation.” (Daubert Tr, 98:6-99:3.) Dr, Rosen explained that the MAUDE anonymous database is a very helpful tool for getting “safety signals and major complication signals” about medical devices. (Daubert Tr. 99:13-24.) Dr. Rosen stated that he “would, always love to see a randomized controlled trial on any material that- is being released,” but “that’s a bar that probably no material can actually achieve — or has achieved....” (Daubert Tr. 99:25-100:10.)

Dr. Rosen testified that a prospective randomized trial would give surgeons the best information about the risks and benefits of the product, but admits that such studies were not routinely done on available mesh products in 2Q09. (Daubert Tr. 100:2-20.) Without such studies, Dr. Rosen explains, “there’s very little instructions about what to expect for the surgeons’ or the patients,” resulting in “life threatening” situations for patients when surgeons don’t “know how to handle complications.” (Daubert Tr. 100:17-101:5.) Dr. Rosen interprets the results of the 2009 MAUDE database study as indicating á problem that should have prompted further study and he “would have liked to have seen a prospective trial started to address whether this is an error or whether or not this is a true signal.” (Daubert Tr. 101:17-21.)

In January, 2010, the same month that Dr. Rosen operated on Mr. Avendt, Dr. Rosen published a peer-reviewed article that he co-authored titled “Biological Mesh for Abdominal Wall Reconstruction: A Critical Appraisal,” which purported to. review the then-available peer-reviewed publications discussing biological grafts for abdominal wall reconstruction. (Dauberi Tr. at 13:12 — 14:6; EOF No, 223, Joint Stipulated Exhibit List Ex. ,1, Michael J. Rosen, “Biologic Mesh for Abdominal Wall Reconstruction:. A Critical Approach,” Am. Surg. 2010 (Jan): 76(1).). The article included a study .of Permacol and in it the authors conclude, and inform surgeons reading this peer-reviewed article, that “Permacol seems to behave reasonably well in clean cases; -Class I wounds.” (Id. at 19:1-17,)-

' In 2012, Dr, Rosen co-authored an article in the peer-reviewed publication Plastic and Reconstructive Surgery titled “The Biology of Biologies: Basic Science and Clinical Concepts,” in which the authors conclude that: “Permacol seems to behave reasonably well in clean cases: however, the effect of cross-linking on infected and contaminated ventral hernia repair remains largely unknown at this time and requires careful evaluation.” (Daubert Tr. 23:19-24:25;. Joint Exhibit List, Ex. 3, “The Biology of Biologies: Basic Science and Clinical Concepts,” Plast. Reconstr. Surg. 130 (Suppl. 2:9S, 2012), at 14S, PgID 6924.) Dr.'Rosen admits that he has never authored an article stating that Permacol is not reasonably safe for use in a Class I wound and has never recommended to anyone in the medical community in any publication that surgeons should not use Permacol in a Class I wound.- (Daubert Tv. 25:24-26:5.) Dr. Rosen is of the further opinion, however, despite these conclusions, that there was “a lack of overall information available” at the time these articles were published. (Daubert Tr, 25:6-19.)

In 2013,. Dr. Rosen co-authored an article titled “Abdominal Wall Reconstruction,” in the publication “Current Problems in- Surgery.” (Daubert Tr. 40:11-25; Joint Exhibit List, Ex. 6, C.D. Butler, D. Bau-man, J. Janis, M. Rosen, “Abdominal Wall Reconstruction,” Current Problems in Surgery 50- (2013) 557-586.) The authors -of this article conclude that a number of bio-logies, including Permacol, “appear to tolerate placement in a clean-contaminated field,” — a Class II wound. (Daubert Tr. 41:11-25.)

■ Dr. Rosen also, testified at the Daubert hearing that he has recommended and used a certain type of “large pore” synthetic mesh, which never remodels in the body as a biologic mesh is designed to do, in Class II and Class III wounds. (Daubert Tr. 26:11-27:5.) Dr. Rosen espoused this opinion in a 2013 article published in the Journal of American College of Surgeons and in a 2015 podcast, i.e. that a “large pore” synthetic mesh would be safe and reasonable to use in Class II (clean contaminated) and even Class III (contaminated) wounds. CDaubert Tr. 27:6-28:9; Joint Exhibit List Ex. 4, August 3, 2015 Behind the Knife: The Surgery Podcast— Audio, Ex. 5 “Outcomes of Synthetic Mesh in Contaminated Ventral Hernia Repairs,” J. Am. Coll. Surg. 2013: 217:991-998 (Dec.).) Specifically, Dr. Rosen acknowledged at the Daubert hearing that he advised in the 2015 podcast that if he encountered a surgical situation in which he nicked the bowel but observed no spillage (the situation that Dr. Ash testified he believed may have occurred when he implanted Permacol in Mr. Avendt), it would be “perfectly appropriate” to use a synthetic “lightweight polypropylene mesh.” cDaubert Tr. 27:15-28:11; Joint Exhibit List, Ex. 4, 2015 Podcast PgID 6930.)

Although Dr. Rosen explained at the Daubert hearing that it was a “very small class of synthetic materials,” i.e. “a large pore synthetic mesh,” that would be appropriate in such a case, he made no such distinction at his deposition when he testified that he would use a Permacol mesh in any situation in which a synthetic mesh would be indicated. At the Daubert hearing, Dr. Rosen was reminded of this testimony from his deposition:

Q: So you can’t think of a single scenario where Permacol mesh is appropriate for use in a patient? Is that fair?

A: The only circumstance that I would think that it’s appropriate for use would be when synthetic mesh is appropriate at a fraction of the price.

(Daubert Tr. 31:23-32:7.) Dr. Rosen is certainly not a fan of biologic mesh and has significant concerns regarding the cost to the healthcare system of the biologic meshes, concluding that “100 pieces of synthetic mesh cost the same as 1 biologic graft,” and wonders whether “the continued use of biologic mesh can be financially solvent.” (Joint Exhibit List, Ex. 5, “Outcomes of Synthetic Mesh” 997, PgID 6938.) But while his published opinions may support the conclusion that certain synthetics may be more cost effective than a biologic, none suggest that Permacol should not have been an available tool for surgeons in 2009. As Dr. Rosen and his co-authors concluded in Abdominal Wall Reconstruction in 2013:

The ideal mesh has not yet been developed but would cause minimal or no inflammatory reaction and be chemically inert, resistant to mechanical stress, sterilizable, noncarcinogenic, hypoallergenic, and reasonably priced. Each of the commercially available meshes has some but not all of these properties.... The use of lightweight polypropylene mesh in the setting of contamination has received renewed interest as a more cost-effective approach than bioprosthetic mesh. Several authors have demonstrated that lightweight polypropylene mesh is relatively resistant to bacterial colonization in experimental models, and small case series have demonstrated safety when utilized in clean-contaminated colorectal cases.... Use of biop-rosthetic materials is & relatively new area in hernia surgery, and further animal and clinical studies are needed to answer many important questions. Currently, these grafts [including Permacol] appear to tolerate placement in a clean-contaminated field, but their long term durability and role in hernia recurrence are largely unknown. Although biop-rosthetic meshes are much more expensive than synthetic meshes, the long-term cost effectiveness of these materials, particularly in contaminated cases, may be better.

(Joint Exhibit List, Ex. 6, Abdominal Wall Reconstruction 563, PgID 6947, 6949.)

Dr. Rosen testified at the Daubert hearing, reviewing his clinic notes, that he first, saw Mr. Avendt in December, 2009. (.Dau-bert Tr. 49:5-6.) Mr. Avendt had undergone three prior hernia repairs when he presented to Dr. Rosen in December, 2009. (Daubert Tr. 50:11-14.) Dr. Rosen could not specifically recall whether, in 2009, he had seen the operative notes relating to Mr. Avendt’s 2008 surgery in which Dr. Ash implanted the Permacol mesh, prior to being asked to'testify in this case, but he testified that his “typical practice” was to obtain such records before a case if possible. (Daubert Tr. 51:22-52:9, 58:13-25.) Dr. Rosen had no knowledge of what was available to Dr. Ash to use at the time he elected' to use Permacol to repair Mr. Avendt’s hernia and Dr. Rosen does not know what went in to Dr. Ash’s ■ decision, he did not recall the wound classification at the- time of Dr. Ash’s implantation of Per-macol nor does he know whether Dr. Ash read the Permacol IFU. (Daubert Tr. 53:3-55:2.)

During his treatment of Mr. Avendt, Dr. Rosen never told Mr. Avendt that he believed that the Permacol implanted by Dr. Ash was defective, or that Mr. Avendt’s problems were caused by the Permacol mesh. (Daubert Tr. 61:1-7.) Dr. Rosen never told any of his colleagues of the experience explanting Permacol from Mr. Avendt, he never made a report to the FDA MAUDE database, none of Dr. Ro-sen’s treatment records mention Permacol or cross-linking and Dr. Rosen never told Dr. Ash that he believed that Permacol was defective. (Daubert Tr. 61:8-62:1.) Dr. Rosen never expressed the opinions he offers in this case until he was asked, which was when counsel for Mr. Avendt called him about testifying in this litigation. (Daubert Tr. 62:2-5.)

Dr. Rosen believes that the sequence of events that led to Mr. Avendt’s’ infection started shortly .after Mr. Avendt’s surgery in- August, 2008, when Dr. Ash implanted the Permacol. (Daubert Tr. 62:6-18.) Dr. Rosen was aware that Dr. Ash performed another abdominal surgery on Mr. Avendt in May, 2009 when Dr. Ash “went back for the seroma.” Dr. Rosen was not aware that a wound culture done at the time of Mr. Avendt’s May, 2009 surgery, when Dr. Ash elected to leave’ the Permacol in place, showed no sign of infection. (Daubert Tr, 62:19-63:4.) Dr. Rosen, who concedes that he-is hot an expert on how the human immune system reacts to Permacol mesh, does not recall that he rah any tests on the explanted Permacol to determine the presence and/or existence of any ingrowth, and did not perforin wound cultures on Mr. Avendt’s wound at any time. (Daubert Tr. 63:10-64:2.) Dr. Rosen does not recall see-ihg Mr. Avendt’s mesh specimen again after removing it, or following up on any pathology report. (Daubert Tr. 65:13-66:9.)

Dr. Rosen recalled that Dr. Ash’s notes from the May, 2009 surgery indicated that Dr. Ash found cracks in the Permacol and repaired those cracks with 3-0 vicryls suture. Dr. Rosen did not recall that Dr. Ash indicated he found “healing Permacol” and “manipulated” the Permacol which created cracks and holes, that Dr. Ash then repaired with an absorbable synthetic suture that would maintain its strength for six to eight weeks. (Daubert Tr. • 67:2-68:11.) When shown Dr. Ash’s operative report from the May 19, 2009 surgery, Dr. Rosen conceded that Dr. Ash did state that in draining the seroma that had formed, he observéd “the healing Permacol mesh,” and it appeared that “the Permacol was in fact quite-brittle and continuous manipulation of the Permacol appeared to have created some cracks and holes in the Per-macol.” (Joint Exhibit List, Ex. 11, 6/19/2009 Dr. Ash Operative Report PgID 6994.) Dr. Ash sutured the holes in the Permacol with “a 3-0 Vicryl stitch” with a “box stitch” and “closed the crack in the Permacol mesh in a running fashion.” (Id.) Although Dr. Rosen had to admit that the words Dr. Ash used were as they were written in Dr. Ash’s operative note, he insisted that “determining healing with a mesh that is falling apart when you touch it‘[was] not consistent with his understanding of the operative report” because in his experience with thousands of patients with mesh, touching a mesh and having it fall apart is “not supposed to happen” with a healing mesh. (Daubert Tr. 70:10-73:4.) Dr., Rosen was- unaware of any textbooks or. published studies that; describe the technique Dr. Ash used to stitch the Per-macol mesh back together but he believed that “any reasonable person faced with this would do something to try to get it back together.” (Dcmberb Tr. 73:6-21.)

Dr. Rosen is of the opinion, despite his published, pe,er-reviewed works proclaiming that Permacol performs reasonably well in clean and clean contaminated cases, that Permacol was not reasonably safe for use in 2009 due to its cross-linked nature and further believes that cross-linked biologic mesh products have not been properly vetted and therefore their potential for failure and complication have been inadequately explained to practicing surgeons. To summarize his opinion testimony at-the Dcmbert hearing:

I think what that means to a clinician like myself is that when these materials are cross-linked, they are resisting degradation by a collagenase-.... And the way clinicians perceive a biologic mesh, and I believe the way it has been marketed to us is that this is a biologic material that allows cells to grow in, fibroblast to come in, regenerate into native tissue which should resist infection and eventually be replaced with host tissue. And I think this is where the confusion and lack of complete knowledge about how these.cross-linked materials are going to change that perception was never fully vetted in that we’re starting to see that the collagenase aren’t able to break up the graft and they’re not being replaced with normal tissue and they’re starting to behave very similar to what-we see with the synthetic material particularly certain types of synthetic materials that stick around and create issues with infection.[0]n the spectrum of biologic to synthetic it is. unclear exactly where this mesh is going to behave and there will be synthetic features to this at times.... [T]his is,why it was so important to have this information up front, because there is going to be some positive features to having a- synthetic-like response in that it might improve durability of the hernia repair. But the unintended and unstudied consequences of getting that synthetic material in-a thick, nonporous graft is what was showing up on the MAUDE database and is what I think we’re seeing, Mr. Avendt, is that these materials are at times dissolving an infection, at times sticking around and not going away. And so they’re very, very difficult to predict thpir behavior when placed in challenging-environments.In Mr. Avendt’s case it’s clear that he had a chronic infection that required a major reconstructive procedure where we had to go in and remove unincorporated mesh..... In my opinion, based on what I understand about cross-linking mesh and having seen many cross-linked failures in our research, [the cause of the product failure] is the fact that the unpredictable behavior-and unstudied behavior of the material resulted in the surgeon at the time when he placed that material and suffered a complication from it, was not really informed on exactly what to do and left behind a piece of mesh that, ultimately, did not become incorporated. We came back, it was covered in pus. and resulted in now what in my opinion is the hardest hernia to . fix [which] is a CDC Class IV wound with a very large defect.

(Daubert Tr. 105:25-108:16.) Dr. Rosen holds this opinion with knowledge that in May of 2009, when Dr. Ash left the Perma-col in Mr. Avendt’s abdomen, he left it in a Class I clean wound, (Daubert Tr. 108:17-25.)

Plaintiffs’ counsel elicited from Dr. Ro-sen testimony at the Daubert hearing that Mr. Avendt’s comorbidities were: common among his patients — “everybody I take care of has those pre-existing conditions,” my “typical patient [is] overweight, diabetic, hypertensive, 20 pounds or more overweight.” (Dmbert Tr, 111:18-112:8.) Dr. Rosen spoke at length at the Dmbert hearing about the hundreds of prosthetic mesh infections that he has treated,, major reconstructive failed hernias, including some involving Permacol, none of which Dr. Rosen could specifically recall. (Dau-bert Tr. 112:14-23.) ...

.. When asked about Dr. Ash’s decision to leave the Permacol in place' in May, 2009, and to stitch it up rather than remove it, Dr. Rosen is not critical of Dr. Ash’s decision, which Dr. Rosen suggests was made due lack of insufficient .information .available to guide Dr. Ash in his decision:

Q; In May of 2009, Dr, Ash chose to leave the Permacol in the — in place. Is it your opinion that should have been removed- or is it — do you have another opinion?

A: Well,. I think at the time, in 2008, we didn’t know any better. I think there just wasn’t any data to instruct surgeons about how to-manage these type of complications. I think at the time any reasonable surgeon would have thought this was a biologic mesh like all other biologic mesh and it will regenerate, revascu-larize and I’ll be okay. And I think, as we can see in this data and mounting data, that’s just, not bearing out to be the case.

Q: And ... is it your opinion based on your experience, research, review of the literature and knowledge nf the patient, is it your opinion that Permacol caused the injury to ... Mr. Avendt that you repaired in January of 2010?

A: Yes, it is, because when I operated on him in January, it' was right there, unincorporated piece of Permacol mesh that was clearly infected, that was leading right to all the sinuses that required a lot of debridement to his abdominal wall and left him with an enormous hernia and.this infected situation.

(Daubert Tr. 113:17-114:14.) Dr. Rosen also opined as to. the insufficiency of the Permacol IFU:.

Q: Did Doctor — did the instructions for use direct users to remove Permacol in the event of a seroma or an infection?

A: I’m not aware that it says that, no.

Q: Is it your professional opinion now that it should say that?

A: It’s my professional opinion that there should be more information to inform that IFÜ particularly for the type of cases and the type of hernias that these products are being placed in, and that should be able to be informed [sic] of surgeons who are putting this in human beings so that we can predict to some reasonable degree what might happen. .

(⅞: Is it your opinion that Permacol should have sufficient labeling to inform a doctor of these side effects? ■

A: In the. absence of a prospective clinical trial that’s better than the MAUDE database, that disputes this data in a well-designed trial that I think this should be made much more clear to surgeons who are putting this in people....

(Daubert Tr. 115:1-20.)

Although of the opinion that the Perma-col IFU is insufficient, Dr. Rosen has no opinion on what the Permaeol IFU should say and acknowledges that he has never written anywhere, in any of publications, as to the substance of the “something more” that he opines the IFU should state. According to Dr. Rosen, he has “never seen a trial that would actually allow me to have that level of certainty to answer that question.” (.Daubert Tr. 138:17-139:3.)

Dr. Rosen concludes, based on the data in the MAUDE database article, that cross-linked meshes are “not safe,” and that this data is “a very loud safety signal that something is happening and we need to go back and look very carefully and figure out who it’s happening to, why this is happening so that we can either modify the material or make a change to make it safer for patients.” (Daubert, Tr. 117:2-20.)

C. Testimony of David Williams

Mr. Williams, a scientist not a physician, is a professor of biomaterials at the Wake Forest Baptist Medical Center in North Carolina. (Defi’s Mot. Ex. F, June 30, 2015 Deposition of David F. Williams 6:21-24.) Mr. Williams, an expert for Covidien, testified at his deposition that the development and design of the Permaeol mesh was appropriate and in accordance with industry standards and sound engineering and biologic practices and principles. (Id. at 42:12-17.) Mr. Williams further testified that the design and manufacture of the Permaeol is reasonable and that the product is safe and appropriate for its intended use. (Id. at 47:6-11.) Plaintiffs have not objected to the admissibility of Mr. Williams’ testimony and opinions.

Mr. Williams’ area of expertise is tissue engineering, using biomaterials and cells of the human body, especially adult stem cells harvested from blood and fatty tissue, to try to encourage regeneration where it did not occur naturally. (Id. at 11:9-20.) Mr. Williams has done research and given expert testimony in several cases regarding tissue ingrowth into polypropylene mesh and the impact of mesh degradation on infection rates. (Id. at 19:15-20:25.) Mr. Williams explains that there are advantages to utilizing “natural tissue products,” such as Permaeol. (Id. at 31:4-8.) In specific, Mr. Williams testifies about the nature and advantages of products, such as Per-macol, based on proteins and more specifically based upon collagen which is derived from either animal or human sources. (Id. at 31:9-17.) In contrast to synthetic mesh, comprised of say polypropylene or polyester, which is non-degradable and non-ab-sorbable and designed to remain in the human body for the life of the patient, natural tissue products, such as the porcine (pig) dermis (skin) used in Permaeol, provide initial strength and form and architecture to a repair but slowly degrade and are replaced by the patient’s' own tissue through ingrowth. (Id. at 31:18-32:13, 33:3-5. The result is tissue that has totally repaired and regenerated rather than relying on a synthetic structure. Id. at 32:11-13.)

Mr. Williams explains that Permaeol is a “cross-linked porcine dermal implant” that, like all other xenogenic (deriving from animals) products, first undergoes a deeellu-larization process to remove the cells of the collagen- to which the human body could be allergic. (Id. at 37:19-38:16.) In addition to decellularization, Permaeol undergoes a further processing called “cross-linking,” through which bonds are established between collagen molecules and fibers by exposure to a solution, in the case of Permaeol a solution called hexamethy-lene diisocyanate (“HMDI”), which gives the product different properties compared to non-cross-linked products. (Id. at .33:7-21, 38:20-25.) Permacol is the only product on the market cross-linked by HMDI. (Id. at 38:23-24.) Unlike other cross-linking products which leave behind a toxic residue, HMDI does not leave toxic residues behind in the collagen. (Id. at 39:8-40:4.)

Mr. Williams explains that cross-linking increases the stability and therefore durability of the product because the cross-link bonds established between the molecules and the fibrils means that certain enzymes in the body which normally degrade collagen will find it more difficult to breakdown the collagen and therefore the product will be more durable and longer lasting, providing greater control between the properties of the biologic material (the porcine dermis) and the speed at which that material is replaced with human tissue through ingrowth. (Id. at 34:1-25.) In contrast to a non-cross-linked biologic, which is quickly remodeled after implantation (a matter of months to maybe a year or so) by the natural collagen of the patient, this process is delayed in the cross-linked material so th