UNITED STATES DISTRICT COURT

SOUTHERN DISTRICT OF OHIO

EASTERN DIVISION

IN RE: DAVOL, INC./C.R. BARD, 

INC., POLYPROPYLENE HERNIA 

MESH PRODUCTS LIABILITY 

LITIGATION

This document relates to: 

Johns v. CR Bard et al, 

Case No. 2:18-cv-1509

 Case No. 2:18-md-2846

 JUDGE EDMUND A. SARGUS, JR.

 Magistrate Judge Kimberly A. Jolson

EVIDENTIARY MOTIONS OPINION AND ORDER NO. 10

This Opinion addresses the Defendants’ Motion to Exclude the Opinion and Testimony of 

Plaintiff’s Expert Jimmy Mays, Ph.D. (ECF No. 30). For the reasons that follow, Defendants’ 

motion is GRANTED IN PART AND DENIED IN PART.

I. Background1

This case is the first bellwether trial, selected from thousands of cases in this multidistrict 

litigation (“MDL”), alleging “that defects in defendants’ polypropylene hernia mesh products can 

lead to complications when implanted in patients, including adhesions.” (No. 2:18-md-02846, 

ECF No. 1 at PageID #1–2.) This includes the Ventralight ST, the device implanted in Plaintiff. 

The Ventralight ST is a prescription medical device used for hernia repairs. In re Davol, Inc./C.R. 

Bard, Inc., Polypropylene Hernia Mesh Prods. Liab. Litig., Nos. 2:18-md-2486, 2:18-cv-01509, 

2020 WL 5223363, at *1–6 (S. D. Ohio Sept. 1, 2020). The Food and Drug Administration 

(“FDA”) cleared it for use through the premarket notification § 510(k) process in 2010 and later 

1 The Court assumes that the parties and other interested readers are familiar with the history of 

this case. For a more complete factual background, the reader is directed to the Court’s summary 

judgment opinion and order. In re Davol, Inc./C.R. Bard, Inc., Polypropylene Hernia Mesh Prods. Liab. 

Litig., Nos. 2:18-md-2486, 2:18-cv-01509, 2020 WL 5223363, at *1–6 (S. D. Ohio Sept. 1, 2020).
2

cleared it for use with the Echo Positioning System in 2011. It is a multicomponent device made 

of a mesh, which consists of polypropylene, polyglycolic acid fibers, and a bioresorbable coating 

called “Sepra Technology” (“ST”). The ST-coated side of the mesh is placed against organs, such 

as the bowels, while the uncoated polypropylene side is placed against the fascia because the 

uncoated side maximizes tissue attachment and thus supports the hernia repair. Id. at *1–2.

Plaintiff brings this action to recover for injuries sustained as a result of the implantation 

of Defendants’ allegedly defective Ventralight ST device. Plaintiff claims that Defendants knew 

that polypropylene is unsuitable for permanent implantation in the human body. Id. at *4. The 

crux of Plaintiff’s claims is that the ST coating on the Ventralight ST resorbs too quickly. This 

leads to the exposure of bare polypropylene to internal organs and tissues, increasing the risk of 

potential complications. Plaintiff alleges that this occurrence led to omental adhesions after his 

laparoscopic hernia repair surgery in 2015. The following claims remain for trial: design defect, 

under negligence and strict liability theories; failure to warn, under negligence and strict liability 

theories; breach of express warranty; breach of implied warranty; breach of implied warranty of 

merchantability; negligent misrepresentation; and punitive damages. Id. at *6–25. Now, various 

evidentiary motions are ripe for adjudication.

II. Legal Standard

“Neither the Federal Rules of Evidence nor the Federal Rules of Civil Procedure explicitly 

authorize a court to rule on an evidentiary motion in limine.” In re E.I. du Pont de Nemours & Co. 

C-8 Pers. Injury Litig., 348 F. Supp. 3d 698, 721 (S.D. Ohio 2016). The practice of ruling on such 

motions “has developed pursuant to the district court’s inherent authority to manage the course of 

trials.” Luce v. United States, 469 U.S. 38, 41 n.4 (1984). “The purpose of a motion in limine is 

to allow a court to rule on issues pertaining to evidence prior to trial to avoid delay and ensure an 
3

evenhanded and expedient trial.” In re E.I. du Pont, 348 F. Supp. 3d at 721 (citing Ind. Ins. Co. v. 

Gen. Elec. Co., 326 F. Supp. 2d 844, 846 (N.D. Ohio 2004)). However, courts are generally 

reluctant to grant broad exclusions of evidence before trial because “a court is almost always better 

situated during the actual trial to assess the value and utility of evidence.” Koch v. Koch Indus., 

Inc., 2 F. Supp. 2d 1385, 1388 (D. Kan. 1998); accord Sperberg v. Goodyear Tire & Rubber Co., 

519 F.2d 708, 712 (6th Cir. 1975) (“A better practice is to deal with questions of admissibility of 

evidence as they arise.”). Unless a party proves that the evidence is clearly inadmissible on all 

potential grounds—a demanding requirement—“evidentiary rulings should be deferred until trial 

so that questions of foundation, relevancy and potential prejudice may be resolved in proper 

context.” In re E.I. du Pont, 348 F. Supp. 3d at 721 (quoting Ind. Ins. Co., 326 F. Supp. 2d at 846). 

The denial, in whole or in part, of a motion in limine does not give a party license to admit all 

evidence contemplated by the motion; it simply means that the Court cannot adjudicate the motion 

outside of the trial context. Ind. Ins. Co., 326 F. Supp. 2d at 846.

The burden is on the party offering the expert testimony to demonstrate by a preponderance 

of proof that the opinions of their experts are admissible. Nelson v. Tenn. Gas Pipeline Co., 243 

F.3d 244, 251 (6th Cir. 2001). Any doubts regarding the admissibility of an expert’s testimony 

should be resolved in favor of admissibility. See Jahn v. Equine Servs., PSC, 233 F.3d 382, 388 

(6th Cir. 2000) (“The Court [in Daubert v. Merrell Dow Pharmaceuticals., Inc., 509 U.S. 579 

(1993),] explained that Rule 702 displays a ‘liberal thrust’ with the ‘general approach of relaxing 

the traditional barriers to “opinion” testimony.’” (quoting Fed. R. Evid. 702)); Fed. R. Evid. 702 

advisory committee’s note to 2000 amendment (“A review of the case law after Daubert shows 

that the rejection of expert testimony is the exception rather than the rule.”).
4

III. Analysis

Expert testimony is admissible if: 

(a) the expert’s scientific, technical, or other specialized knowledge will 

help the trier of fact to understand the evidence or to determine a fact in 

issue; 

(b) the testimony is based on sufficient facts or data; 

(c) the testimony is the product of reliable principles and methods; and 

(d) the expert has reliably applied the principles and methods to the facts 

of the case.

Fed. R. Evid. 702. In this circuit, “[t]he Rule 702 analysis proceeds in three stages.” 

United States v. Rios, 830 F.3d 403, 413 (6th Cir. 2016). “First, the witness must be 

qualified by ‘knowledge, skill, experience, training, or education.’ Second, the testimony 

must be relevant, meaning that it ‘will assist the trier of fact to understand the evidence 

or to determine a fact in issue.’ Third, the testimony must be reliable.” In re Scrap Metal 

Antitrust Litig., 527 F.3d 517, 529 (6th Cir. 2008) (citations omitted). Only the latter two 

steps are at issue here.

Dr. Mays is a materials scientist with an expertise in polymer science. (ECF No. 30 at

PageID #791.) Defendants challenge his opinions related to the oxidative degradation of

polypropylene in the body, biosorbable polymers, expanded poly(tetrafluoroethylene) (“ePTFE”),

and poly(ethylene terephthalate) (“PTE”). (Id. at PageID #788.) Defendants argue that his

opinions are irrelevant and unreliable, and that some opinions impermissibly summarize events

and evaluate defendants’ knowledge and state of mind. (Id. at 796–809.) Some, but not all, of Dr.

Mays’s opinions are irrelevant, unreliable, and address impermissible topics.

A. Relevance

Expert testimony must be relevant, meaning it will “help the trier of fact to understand the 

evidence or to determine a fact in issue.” Bradley v. Ameristep, Inc., 800 F.3d 205, 208 (6th Cir. 
5

2015) (quoting United States v. Freeman, 730 F.3d 590, 599–600 (6th Cir. 2013)); see also Fed. 

R. Evid. 702(a). “Expert testimony which does not relate to any issue in the case is not relevant 

and, ergo, non-helpful.” Daubert v. Merrell Dow Pharms., Inc., 509 U.S. 579, 591 (1993) (quoting 

3 Weinstein & Berger ¶ 702[02], p. 702–18). “This requirement has been interpreted to mean that 

scientific testimony must ‘fit’ the facts of the case, that is, there must be a connection between the 

scientific research or test result being offered and the disputed factual issues in the case in which 

the expert will testify.” Pride v. BIC Corp., 218 F.3d 566, 578 (6th Cir. 2000) (citing Daubert, 

509 U.S. at 592). This is a case-specific inquiry. Madej v. Maiden, 951 F.3d 364, 370 (6th Cir. 

2020) (“Whether an opinion ‘relates to an issue in the case’ or helps a jury answer a ‘specific 

question’ depends on the claims before the court.”). 

Dr. Mays’s general causation opinions and testimony are relevant to the extent that he

discusses the degradation of polypropylene. His opinion that polypropylene degrades via

oxidation in the body is consistent with Plaintiff’s theory of injury in this case, which is that the

ST coating of the Ventralight ST resorbed too quickly and that the exposure of bare polypropylene

caused his adhesions. E.g., In re Davol, Inc./C.R. Bard, Inc., Nos. 2:18-cv-01509, 2:18-md-2846,

2020 WL 6603657, at *3 (S.D. Ohio Oct. 20, 2020). Thus, Dr. Mays’s opinionsfit the case because

there is a “connection” between his testimony and “the disputed factual issues in the case.” Pride,

218 F.3d at 578. 

Defendants argue that Dr. Mays’s opinions are irrelevant because there is no connection

between degradation of polypropylene mesh in the body and adhesions, nor is there a connection

between Dr. Mays’s generic polypropylene opinions and the Ventralight ST. (ECF No. 30 at

PageID #796–99.) In this Court’s summary judgment opinion, it held that material questions of

fact remained regarding whether in vivo oxidative degradation of polypropylene caused Plaintiff’s
6

omental adhesions. In re Davol, Inc., 2020 WL 5223363, at *13–14. And as this Court has

explained before, an expert’s opinions are not irrelevant because the expert “does not link them to

Plaintiff’s specific injuries.” In re Davol, Inc./C.R. Bard, Inc., Polypropylene Hernia Mesh Prods.

Liab. Litig., Nos. 2:18-cv-01509, 2:18-md-2846, 2020 WL 6605542, at *21 (S.D. Ohio Sept. 1,

2020). “A single expert need not provide all the pieces of the puzzle for their testimony to be

useful to the jury in determining the ultimate issues in the case.” In re Ethicon, Inc. Pelvic Repair

Sys. Prod. Liab. Litig., No. 2327, 2016 WL 4536456, at * 2–3 (S.D.W. Va. Aug. 30, 2016)

(denying motion to exclude expert’s degradation and toxicity opinion despite expert’s inability to

connect them to plaintiffs’ injuries because his testimony was “a relevant step towards establishing

general causation.”). Dr. Mays is not a specific-causation expert, so he need not provide the direct

link to Plaintiff’s injuries himself. He opines that polypropylene, a material that the Ventralight

ST is made of, degrades oxidatively in the body, the mechanism that Plaintiff argues caused his

adhesions. Accordingly, his opinions are relevant.

Some of Dr. Mays’s opinions are irrelevant, however. Plaintiff references Dr. Mays’s

opinions regarding hernia recurrence, pain, and inflammation that is unrelated to the formation of

adhesions (ECF No. 68 at PageID #3443–44), which are no longer viable injuries in this case, In

re Davol, Inc., 2020 WL 5223363, at *14. Plaintiff also concedes that any opinions related to

cancer are not relevant to this case. (ECF No. 68 at PageID #3454.) Dr. Mays’s opinions regarding

ePTFE and PET are also irrelevant because these chemicals are present in “permanent composite

meshes,” such as the Composix Kugel, but do not appear to be in “partially resorbable composite

meshes,” which includes the Ventralight ST. (ECF No. 30-1 at PageID #819.) Plaintiff fails to

address the relevance of ePTFE and PET in any manner.
7

B. Reliability

Rule 702 provides the following general standards to assess reliability: whether “the 

testimony is based on sufficient facts or data,” whether “the testimony is the product of reliable 

principles and methods,” and whether “the expert has applied the principles and methods reliably 

to the facts of the case.” Fed. R. Evid. 702(b)–(d). To evaluate reliability of principles and 

methods, courts consider “‘testing, peer review, publication, error rates, the existence and 

maintenance of standards controlling the technique’s operation, and general acceptance in the 

relevant scientific community,’” though these factors “‘are not dispositive in every case’ and 

should be applied only ‘where they are reasonable measures of the reliability of expert testimony.’” 

In re Scrap Metal, 527 F.3d at 529 (citations omitted); see Daubert, 509 U.S. at 594 (describing 

these factors as “flexible”). The objective of the reliability requirement is to “make certain that an 

expert, whether basing testimony upon professional studies or personal experience, employs in the 

courtroom the same level of intellectual rigor that characterizes the practice of an expert in the 

relevant field.” Kumho Tire Co., Ltd. v. Carmichael, 526 U.S. 137, 152 (1999). 

Defendants raise four arguments regarding the reliability of Dr. Mays’s opinions: (1) that

Dr. Mays’s opinions do not satisfy the requisite level of certainty, (2) that he failed to account for

certain factors while forming his opinions, (3) that he based his opinion on statements in Material

Safety Data Sheets (“MSDSs”) for polypropylene resin, and (4) that he failed to independently

validate Dr. El-Ghannam’s findings in reaching his pre-implantation oxidative degradation

opinion. Only Defendants’ MSDS argument finds traction, however. 

1. Requite level of certainty

The Sixth Circuit has remarked that “the majority of courts require that an expert opinion

express a probability, which is more than a mere possibility.” Johnson v. Memphis Light Gas &
8

Water Div., 695 F. App’x 131, 137 (6th Cir. 2017). But this is not a “‘magic words’ test.” Id. at

136 (quoting Thompson v. Underwood, 407 F.2d 994, 997 (6th Cir. 1969)). “And the fact that an

expert ‘does not use absolute terms but rather couches the opinions in terms of “can” or “may”

does not render it speculative or unreliable.’” In re Heparin Prods. Liab. Litig., 803 F. Supp. 2d

712, 745 (N.D. Ohio 2011) (quoting In re Trasylol Prods. Liab. Litig., No. 08-MD-01928, 2010

WL 1489730, *8 (S.D. Fla. Mar. 19, 2010)). In other words, the district court must assess the

whole of the expert’s opinion, not isolated instances of word choice. Here, Dr. Mays’s report is

far from speculative—he opines that for a variety reasons and factors, polypropylene is capable of

oxidative degradation in vivo and that this degradation will occur in the polypropylene present in

Defendants’ devices. (ECF No. 30-1 at PageID #820–21.) 

Defendants point to a handful of instances of allegedly equivocal word choice in Dr.

Mays’s report (ECF No. 30 at PageID #799), but this is insufficient to render Dr. Mays’s expert

report speculative. For instance, Defendants’ point to Dr. Mays’s use of the word “susceptible” in

his summary of his opinions (id.), but it Dr. Mays clearly concludes in the next few paragraphs

“that all polypropylene hernia mesh implants will degrade in vivo” and that Defendants’ mesh

devices “are subject to oxidative degradation and will, foreseeably, degrade in the body when

implanted as a permanent medical implant.” (ECF No. 30-1 at PageID #820–21.) Defendants

seek to disqualify expert opinions that contain words like “may,” but this is simply a version of

the “magic words” test that the Sixth Circuit forbids. 

Defendants’ position also finds no precedential support. In each decision cited, specificcausation experts were unable to conclude that an event was the probable cause of the plaintiff’s

injury. In Davison v. Cole Sewell Corp., the Sixth Circuit held that the district court did not abuse

its discretion when it excluded expert testimony in which the expert could only identify possible
9

proximate causes of injury—more than sixteen. 231 F. App’x 444, 450 (6th Cir. 2007); see also

Hutson v. Coviden Holding, Inc., No. 2:13-cv-895, 2015 WL 4040447, at *4 (S.D. Ohio June 30,

2015) (excluding expert testimony because the expert could not further rule out possible causes

and opined that there were four possibilities of causation). Far from ruling in too many

possibilities, Dr. Mays clearly concludes that oxidative degradation occurs.

2. Failure to evaluate certain factors

Next, Defendants argue that Dr. Mays’s opinions are unreliable because he did not evaluate

particular factors. (ECF No. 30 at PageID #801–03.) Defendants argue that Dr. Mays did not

account for the induction period, i.e. the period before the polypropylene mesh oxidizes in vivo, or

the degradation rate of Defendants’ devicesin Plaintiff or the other plaintiffs in this MDL, meaning

that “Dr. Mays cannot rule out the possibility that Plaintiff’s mesh was still within the induction

period and did not have mesh degradation.” (Id. at PageID #802.) Defendants also explain that

because Dr. Mays did not provide a rate of degradation, he cannot determine to what degree of

oxidative degradation occurred on Plaintiff’s mesh. (Id.) And finally, Defendants contend that

Dr. Mays did not “confirm[ ] that Plaintiff’s Ventralight ST or any [of] Bard’s hernia mesh

contracted.” (Id. at PageID #802–03.)

Defendants arguments are unpersuasive because they are iterations of Defendants’ prior

contention that Dr. Mays does not adequately tie his opinions to Plaintiff and his injuries, i.e.

provide specific-causation opinions. As stated above, Dr. Mays’s opinions as a general-causation

expert are relevant and he is not required to supply every link in Plaintiff’s chain of logic for his

theory of the case. Supra Part III.A. Defendants can argue at trial that Plaintiff fails to demonstrate

specific-causation, but Defendants’ arguments do not address the reliability of Dr. Mays’s expert

report or testimony.
10

3. MSDS statements

Defendants assert that Dr. Mays’s opinion that polypropylene is unsuitable for permanent

implantation in the human body is unreliable because he relied on the MSDSs. (ECF No. 30 at

PageID #807–08.) Defendants’ emphasis on the MSDS is overblown, however. Dr. Mays relies

on a variety other grounds throughout his report to reach his conclusion that polypropylene is

unsuitable for permanent implantation, including his own research and ample scientific research. 

(ECF No. 30-1.) Dr. Mays’s reliance on statements from MSDSs is insufficient to render his entire

opinion unreliable. 

Whether Dr. Mays may reference and rely on the MSDS in any manner in giving his

opinions is another matter, however. Dr. Mays refers to the MSDS in two ways. First, he opines

why the MSDS contained that statement and describes the information in the pertinent MSDSs. 

(ECF No. 30-1 at PageID #831–32.) Second, he refers to the MSDS statements that the

polypropylene is unsuitable for permanent medical implantation. (Id. at PageID #820–21.) The

Court concludes that he may not make these references. 

Dr. Mays cannot opine on why a corporation included certain language in the MSDS

because the knowledge of a corporation is beyond the realm of expert testimony. Wise v. C.R. 

Bard, Inc., No. 2:12-cv-01378, 2015 WL 521202, at *23 (S.D.W. Va. Feb. 7, 2015) (evaluating 

the same statement in the same MSDS); Tyree v. Bos. Sci. Corp., 54 F. Supp. 3d 501, 574–75

(same) (S.D.W. Va. 2014). Accordingly, Dr. Mays cannot opine that “[i]n light of these facts,” 

i.e. Dr. Mays’s survey of pertinent scientific literature, “the [MSDS] for Marlex polypropylene 

cautions against using the material in human body” and “against exposure to strong oxidating 

agents.” (ECF No. 30-1 at PageID #831.) 

Dr. Mays also may not reference the MSDS because Plaintiff does not meet his burden to
11

show that the MSDSs are reliable sources for Dr. Mays to base any part of his opinion upon, as is

his burden. Nelson, 243 F.3d at 251; cf. In re Davol, Inc./C.R. Bard, Inc., 2020 WL 6603657, at 

*4 (concluding that the MSDS could not be admitted for the truth of the matter under Federal Rule 

of Evidence 803(18) because “Plaintiff has not established the MSDS as a reliable authority that 

Marlex polypropylene should not be used in permanent implants in the body”). Plaintiff simply

argues that Dr. Mays relies in small part on the MSDS. (ECF No. 68 at PageID #3455.) In the

event that Plaintiff calls Dr. Mays to testify, Dr. Mays may not reference the MSDSs in his

testimony unless Plaintiff seeks prior permission and shows that the MSDSs are reliable sources

for Dr. Mays to rely on.

4. Failure to independently validate Dr. El-Ghannam’s findings

Finally, Defendants assert that Dr. Mays’s opinion that oxidative degradation occurs prior

to implantation in pristine meshes based on Dr. El-Ghannam’s research should be excluded

because Dr. Mays did not independently validate Dr. El-Ghannam’s opinion. (ECF No. 30 at

PageID #809.)2

 Specifically, Defendants point to Dr. El-Ghannam’s Fourier Transform Infrared

Spectrometry (“FTIR”) analysis (ECF No. 30-1 at PageID #883), which was performed with the

diffuse reflectance mode (“DRIFTS”) (ECF No. 68-4 at PageID #3958, pp. 315–16). Previously,

the Court held that Dr. El-Ghannam’s degradation opinions, including his DRIFTS FTIR analysis

of pristine meshes, are admissible. In re Davol, Inc./ C.R. Bard, Inc., Polypropylene Hernia Mesh

Prods. Liab. Litig., Nos. 2:18-cv-01509, 2:18-md-2846, 2020 WL 6603389, at *6–9 (S.D. Ohio

Sept. 10, 2020).3

 Even though Dr. Mays did not independently validate Dr. El-Ghannam’s

2 Defendants again argue that Dr. Mays’s inclusion of the word “susceptible” renders an opinion 

equivocal. (ECF No. 30 at PageID #809.) Dr. Mays’s opinions are not equivocal when assessed as a

whole. See supra Part III.B.1. 3 In Dr. Mays’s expert report, he noted that the Ventralight ST polypropylene fibers peaked at 

1440 cm in Dr. El-Ghannam’s FTIR analysis. (ECF No. 30-1 at PageID #884.) He later testified that 

that “1440 cm” should have read “1740 cm.” (ECF No. 68-4 at PageID #3957, pp. 311–12.)
12

findings, his opinions based on Dr. El-Ghannam’s findings are reliable.

“Experts are permitted wide latitude in their opinions, including those opinions not based

on firsthand knowledge. An expert is able to base an opinion on another expert witness for a point

of expert knowledge not personally possessed.” In re E.I. Du Pont De Nemours & Co. C-8 Pers.

Injury Litig., 337 F. Supp. 3d 728, 743 (S.D. Ohio 2015) (citations omitted); see also Buck v. Ford

Motor Co., 810 F. Supp. 2d 815, 844 (N.D. Ohio 2011) (reviewing published studies). Thus,

experts with appropriate expertise may review scientific literature and other expert reports to form

their opinions. See In re E.I. Du Pont, 337 F. Supp. 3d at 743–44. But an expert may not simply

parrot another expert’s opinion. Hutson, 2015 WL 4040447, at *4 (“In any event, ‘[a]n expert

must make some findings and not merely regurgitate another expert’s opinion.’” (quoting Buck,

810 F. Supp. 2d at 844)); In re Whirlpool Corp. Front-Loading Washer Prods. Liab. Litig., 45 F.

Supp. 3d 724, 741 & n.6 (N.D. Ohio 2014). 

Dr. Mays’s opinion that polypropylene fibers begin to oxidize prior to implantation is

reliable. Dr. Mays is an expert in material science, specifically polymers, and Dr. El-Ghannam’s

opinion regarding pre-implantation degradation is well within Dr. Mays’s expertise. Moreover,

Dr. Mays makes many of his own findings, which are well-supported by scientific literature and

his own testing and experience. For these reasons, he is more than capable of critically assessing

the veracity of Dr. El-Ghannam’s results—which Dr. Mays did. He compared the peak of the

Ventralight ST polypropylene of Dr. El-Ghannam’s FTIR analysis with his own oxidative

degradation results and the results in other scientific literature. (ECF No. 68-4 at PageID #3958,

pp. 316–17.) This is sufficient to convey reliability under Rule 702.

Defendants take issue with Dr. Mays’s testimony that he “did not review [Dr. ElGhannam’s] report in detail” and that he “simply looked at [Dr. El-Ghannam’s] experimental
13

results,” (ECF No. 68-4 at PageID #3958, p. 316), meaning that Dr. Mays “cannot verify the

reliability of [the testing] or that Dr. El-Ghannam properly followed any testing protocols,” (ECF

No. 30 at PageID #809.) But Defendants provide no authority that demonstrates Dr. Mays cannot

verify Dr. El-Ghannam’s testing based on his own expertise and his comparison of the results to

his own work and a substantial body of scientific literature. Defendants’ critiques of Dr. ElGhannam’s FTIR testing is best suited for cross examination of Dr. El-Ghannam, and their critique

of Dr. Mays’s acceptance of that type of FTIR testing is most appropriate for cross-examination

of Dr. Mays.

4

C. Impermissible topics of expert testimony

Defendants seek to exclude the section of Dr. Mays’s report titled “Bard Internal

Documents Regarding the Mesh Used in Their Products” because it does not address proper

subjects of expert testimony. Specifically, Defendants assert that in this section Dr. Mays gives

state-of-mind opinions and inappropriately summarizes events. (ECF No. 30 at PageID #803–04;

ECF No. 86 at PageID #5881.) The Court concludes that Dr. Mays’s report addresses improper

topics, with one exception.

5

First, Dr. Mays overtly opines that Defendants were aware of certain events or facts or

4 Plaintiff argues that before Dr. Mays received Dr. El-Ghannam’s report, Dr. Mays reached his 

opinion that oxidative degradation occurs in polypropylene prior to implantation. (ECF No. 68 at PageID 

#3457.) Defendants misinterpret this argument by construing it as one that Dr. Mays did not rely at all

on Dr. El-Ghannam’s FTIR results. (ECF No. 86 at PageID #5882.) But Plaintiff misinterprets the 

conclusions of Dr. Mays’s report. It is clear that Dr. Mays did not reach a conclusion that oxidative 

degradation of polypropylene occurs prior to implantation without considering Dr. El-Ghannam’s results. 5 This section of Dr. Mays’s report also addresses PET rings and injuries such as infection, small 

bowel obstruction, fistula, and cancer. (ECF No. 30-1 at PageID #871–72.) Dr. Mays’s opinions 

regarding PET are irrelevant. Supra Part III.A. And opinions regarding injuries that Plaintiff does not 

have or for which there is no reasonable certainty he will ever develop those injuries are inadmissible. 

This Court previously has rejected the admission of “potential” harms without “a reasonable certainty

that Mr. Johns will” suffer that harm. (ECF No. 322 at PageID #17275 (addressing cancer)); In re Davol,

Inc./C.R. Bard, Inc., Polypropylene Hernia Mesh Prods. Liab. Litig., Nos. 2:18-cv-01509, 2:18-md-2846,

2020 WL 6604989, at *1 (S.D. Ohio Sept. 11, 2020). “[U]nless there’s a manifestation of proof of a

condition that’s occurred, a future fear of non-cancerous conditions is excluded.” (ECF No. 322 at

PageID #17275.) Accordingly, Dr. Mays may not offer opinions on these topics. 
14

possessed a certain state of mind. This is improper because an expert cannot offer an opinion on

the “intent, motives or states of mind of corporations” because these opinions “have no basis in

any relevant body of knowledge or expertise.” In re Rezulin Prods. Liab. Litig., 309 F. Supp. 2d

531, 546 (S.D.N.Y. 2004)”); supra Part III.B.3. In multiple instances, Dr. Mays reviews

Defendants’ internal documents and infers that Defendants knew a fact or made a decision for a

particular reason. (E.g., No. 30-1 at PageID #867 (“Bard was well aware”), 873 (“Bard had reason

to be concerned of . . . the serious inflammation issues associated with PGD”), 874 (“It thus seems

that Bard’s decision to add BHA to its Sepra material is to suppress this oxidative attack.”).) He

cannot offer these conclusions as an expert; the jury is capable of drawing their own inferences 

about what Defendants knew and did not know based on the internal documents without Dr. 

Mays’s assistance. See In re E. I. du Pont de Nemours & Co. C-8 Pers. Injury Litig., 345 F. Supp.

3d 897, 914 (S.D. Ohio 2015) (“While a witness may testify as to facts and an expert asto opinions,

only a jury may draw inferences.”); see also United States v. Kilpatrick, 798 F.3d 365, 380 (6th

Cir. 2015) (“It is not ‘helpful’ when a witness, lay or expert, forms conclusions for a jury that the

jurors are competent to reach on their own.” (quoting Freeman, 730 F.3d at 597)). 

Second, most of this portion of Dr. Mays’s report is an inadmissible historical recounting. 

A history without any expert analysis or other application of the expert’s expertise is simply a

factual narrative that “should be presented to the jury directly.” In re Trasylol Prods. Liab. Litig.,

709 F. Supp. 2d 1323, 1346 (S.D. Fla. 2010) (explaining that such expert testimony is unhelpful

to the jury); In re Rezulin, 309 F. Supp 2d. at 551 (noting that “percipient witnesses and

documentary evidence” are more appropriate venues to introduce relevant history than expert

testimony). For example, the court in In re Trasylol concluded that an expert’s summaries of

emails between defendants’ employees without analysis were inadmissible. 709 F.3d at 1346 &
15

n.30. Moreover, the court also concluded that factual summaries that suggested the defendant’s

motives were also inadmissible expert testimony. There, the expert opined that the defendant

failed to conduct appropriate testing to obtain FDA approval for a full dose of a medication but

nevertheless “slipped information into its products insert” to suggest that a full dose conferred a

certain benefit. Id. at 1346. The court concluded that “[t]his opinion does nothing more than rely

on [the defendant’s] internal documents to improperly opine on [the defendant’s] motive.” Id.

In contrast, expert testimony that relies on expert knowledge and experience to

contextualize, analyze, and interpret historical facts is admissible. For example, in the In re E.I.

Du Pont de Nemours & Co. MDL, this Court concluded that it was appropriate for a corporateconduct expert, an expert who would opine on the applicable standard of care, to “utilize[ ] his

expertise and training in analytical chemistry, and his knowledge of how the state of the art

methods developed over time, to contextualize the case specific facts against general developments

in analytical methods.” 345 F. Supp. 3d 920, 927 (S.D. Ohio 2015). And for another expert, this

Court reached a similar conclusion, noting that the expert could discussthe factual record or history

to help the jury assess fifty years of corporate conduct in regulatory, scientific, and technical fields

to rebut the defendants’ assertion that it “complied with all applicable industrial and scientific

standards of care, but that it was proactive in that regard and demonstrated exemplary conduct

throughout its entire history.” In re E.I. Du Pont de Nemours & Co., 345 F. Supp. 3d 897, 904

(S.D. Ohio 2015); cf. In re Rezulin, 309 F. Supp. 2d at 551 (“Likewise, the glosses that Dr. Gale

interpolates into his narrative are simple inferences drawn from uncomplicated facts that serve

only to buttress plaintiffs’ theory of the case.”).

Most of this part of Dr. Mays’s report does not analyze, contextualize, or interpret pertinent

factual history. The facts reported by Dr. Mays amount to quoting uncomplicated internal
16

documents that track the history of Defendants’ acquisition and use of different brands of

polypropylene resin. For instance, the first paragraphs of this section describe logistical hurdles

that Defendants faced while obtaining polypropylene and how this led to switching to a different

manufacturer. (ECF No. 30-1 at PageID #867–68.) This is not the complicated, technical history

of a defendants’ conduct beyond the understanding of the average juror as in the Du Pont MDL.

Even in more technical instances in this part of Dr. Mays’s report, the implication is

straightforward. In discussing the storage of polypropylene, Dr. Mays quotes Defendants’ own

testing that indicated extruded polypropylene resin “yard” should be used within nine months, but

that Defendants stored the yard for more than ten years. (Id. at PageID #869.) The jury can reach

its own conclusions regarding Defendants’ conduct based on Defendants’ statements without the

assistance of Dr. Mays. (See also id. at PageID #873 (discussing other shelf-life issues that a jury

would be able to understand).)

In other instances, Dr. Mays’s historical summary clearly assigns a motive to Defendants. 

For example, Dr. Mays recounts the history of Defendants’ acquisition of bioresorbable polyesters

and ultimately interprets an email to conclude that “Bard continually reuses to take prompt action

to properly investigate and/or resolve known or potential issues before others are harmed.” (Id. at

PageID #874.) This is impermissible.

In only one instance can the Court discern an appropriate opinion in this section of Dr.

Mays’sreport. Dr. Mays contextualizes and refersto research explaining why Defendants’ internal

communications stating that the functional lifetime of the polypropylene devices is ten years or

more is dubious in light of his expertise. (Id. at PageID #870.) He points to studies that discuss

in vivo oxidation and how the “permanent” designation of the devices is problematic given his own

study thatshowed oxidative degradation in polypropylene from sixteen to fifty-seven months. (Id.) 
17

At the crux of the case is the reasonableness of Defendants’ conduct, and Dr. Mays’s expert

assessment of these communications is useful to the jury. 

Plaintiff counters that Dr. Mays is permitted to review Defendants’ internal documents and

summarize them. (ECF No. 68 at PageID #3452.) Plaintiff ignores the critical caveat, however,

which is that expert testimony must assist the jury, which, as explained above, the majority of this

portion of Dr. Mays’s report fails to do because the jury may reach these inferences on its own. 

See Fed. R. Evid. 702(a). Moreover, “an expert may testify about his or her review of internal

corporate documents solely for the purpose of explaining the basis for his or her opinions.” In re

Davol, Inc., 2020 WL 6605542, at *11 (emphasis added) (quoting Sanchez v. Bos. Sci. Corp., No.

2:12-CV-05762, 2014 WL 4851989, at *4 (S.D.W. Va. Sept. 29, 2014)). But the distinction

between inadmissible narration of internal documents and admissible expert testimony is the

expert’s actual reliance on the internal documents in forming his expert opinions. See In re C. R.

Bard, Inc., 2018 WL 4220602, at *4 (“[T]hough an expert may not simply narrate corporate

documents in front of the jury, he may rely on such information in forming and supporting his

opinions.”); see also In re Mentor Corp. ObTape Transobturator Sling Prods. Liab. Litig., 711 F.

Supp. 2d 1348, 1368 (M.D. Ga. 2010). Plaintiff explains that this portion of Dr. Mays’s report is

a “review and analysis of internal documents that support and explain his conclusions, including .

. . that Defendants’ meshes at issue in this litigation are not suitable as permanent medical

implants.” (ECF No. 68 at PageID #3451.) This is far too general; Plaintiff provides no other

explanation of how Dr. Mays actually relied on Defendants’ internal documents to reach his

opinions. Thus, Plaintiff does not meet his burden to show this part of Dr. Mays’s expert report is

admissible.

IV. Conclusion

Accordingly, Dr. Mays’s opinions are admissible except for those related to hernia
18

recurrence, pain, inflammation that is unrelated to the formation of adhesions, ePTFE, PET, 

cancer, MSDSs, state-of-mind opinions, and historical narration without the application of his 

expertise. Supra Page 13 n.5. Thus, Defendants’ motion to exclude Dr. Mays’s opinions and 

testimony (ECF No. 30) is GRANTED IN PART AND DENIED IN PART.

IT IS SO ORDERED.

6/28/2021____________ s/ Edmund A Sargus, JR. _________

DATE EDMUND A. SARGUS, JR.

UNITED STATES DISTRICT JUDGE