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. 11

This Opinion addresses Plaintiff’s Motion to Exclude the Opinions and Testimony of

Defense Expert Robert D. Tucker, Ph.D., M.D. (ECF No. 42) and Plaintiff’s Motion to Exclude 

the Opinions and Testimony of Defense Expert James M. Anderson, M.D., Ph.D. (ECF No. 399).

For the reasons that follow, both motions are 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.” 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 (S. D. Ohio Sept. 1, 2020). This includes the Ventralight ST, the device 

implanted in Plaintiff. The Ventralight ST is a prescription medical device used for hernia repairs.

The Food and Drug Administration (“FDA”) cleared it for use through the premarket notification 

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 Products

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

Sept. 1, 2020).

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510(k) process in 2010 and later cleared it for use with the Echo Positioning System in 2011. The 

Ventralight ST is a multicomponent device made of a mesh that consists of polypropylene, 

polyglycolic acid fibers, and a bioresorbable hydrogel 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, thus supporting 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. Id. at *4. The crux of Plaintiff’s claims 

is that the ST coating on the Ventralight ST resorbs too quickly. Id. at *13. This leads to the 

premature 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. Plaintiff asserts that Defendants knew that 

polypropylene is unsuitable for permanent implantation in the human body. Id. at *2–4. 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 

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

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 Daubert, 509 U.S. at 588)); Fed. R. Evid. 

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

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

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III. Analysis

Expert testimony, i.e. testimony given by “[a] witness who is qualified as an expert 

by knowledge, skill, experience, training, or education,” 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) (quoting Fed. R. Evid. 702). 

First, an expert witness must be qualified by “knowledge, skill, experience, training, or 

education.” Fed. R. Evid. 702. “[T]he issue with regard to expert testimony is not the 

qualifications of a witness in the abstract, but whether those qualifications provide a foundation 

for a witness to answer a specific question.” Madej v. Maiden, 951 F.3d 364, 370 (6th Cir. 2020) 

(quoting Berry v. City of Detroit, 25 F.3d 1342, 1351 (6th Cir. 1994)). “[T]he only thing a court 

should be concerned with in determining the qualifications of an expert is whether the expert’s 

knowledge of the subject matter is such that his opinion will likely assist the trier of fact in arriving 

at the truth. The weight of the expert’s testimony must be for the trier of fact.” Mannino v. Int’l

Mfg. Co., 650 F.2d 846, 851 (6th Cir. 1981). A party’s expert need only meet the “‘minimal 

qualifications’ requirement—not one who could teach a graduate seminar on the subject.” Burgett

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v. Troy-Bilt LLC, 579 F. App’x 372, 377 (6th Cir. 2014) (quoting Mannino, 650 F.2d at 851); see 

also Dilts v. United Grp. Servs., LLC, 500 F. App’x 440, 446 (6th Cir. 2012) (“An expert’s lack 

of experience in a particular subject matter does not render him unqualified so long as his general 

knowledge in the field can assist the trier of fact.”). 

Second, expert testimony must be relevant. Expert testimony is relevant if 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. 2015) (quoting United States v. Freeman, 730 F.3d 590, 599–600 (6th 

Cir. 2013)); 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 J. Weinstein & M. Berger, Weinstein’s Evidence ¶ 702[02], p. 702–18 (1988)). 

“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, 951 F.3d at 370. (“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.”). 

Third, expert testimony must be reliable. 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 the reliability of an opinion, courts also 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 

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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 also 

Kumho Tire Co., Ltd. v. Carmichael, 526 U.S. 137, 150 (1999) (describing these factors as 

“flexible” (quoting Daubert, 509 U.S. at 594)). 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, 526 U.S. at 152. 

Plaintiff seeks to exclude the opinions and testimony Dr. Robert D. Tucker, M.D., Ph.D. 

and Dr. James M. Anderson, M.D., Ph.D. 

A. Robert D. Tucker, M.D., Ph.D.

Dr. Tucker is a pathologist and a researcher in biomedical studies, biomedical engineering,

and minimally invasive surgeries. (ECF No. 42-1 at PageID #2337.) Plaintiff argues that four of

Dr. Tucker’s opinions should be excluded. He challenges Dr. Tucker’s (1) causation opinions, (2)

FDA opinions, (3) pore size opinions, and (4) Material Safety Data Sheet (“MSDS”) opinions. At

this time, Dr. Tucker’s FDA and MSDS opinions are inadmissible.

1. Causation opinions

Plaintiff asserts that Dr. Tucker’s causation opinions are unreliable specific causation

opinions (ECF No. 42 at PageID #2325–27; ECF No. 104 at PageID #7182–83) and that Dr.

Tucker is unqualified to offer any causation opinions, whether general or specific (ECF No. 104

at PageID #7182–83). Defendants argue that Dr. Tucker’s opinions are general causation opinions

that Dr. Tucker is qualified to offer. (ECF No. 87 at PageID #5891–92.) Dr. Tucker appears to

offer general causation opinions, and he is qualified to do so.

First, the type of opinion Dr. Tucker offers. General causation evidence in this case

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demonstrates that the Ventralight ST is capable of “caus[ing] the type of injury that a plaintiff

alleges” and specific causation evidence shows that the Ventralight ST caused harm to Plaintiff. 

Madej, 951 F.3d at 369. A “differential diagnosis” or “diagnosis of exclusion” is “considered to

be ‘a standard scientific technique’” for an expert to determine specific causation. Johnson v.

Memphis Light Gas & Water Div., 695 F. App’x 131, 138 (6th Cir. 2017) (citations omitted); see

also In re E.I. du Pont de Nemours & Co. C-8 Pers. Injury Litig., No. 2:18-cv-00136, 2019 WL

6894069, at *3 (S.D. Ohio Dec. 18, 2019) (noting this is an appropriate method for determining

specific causation). A differential diagnosis does not speak to general causation. See Kerner v.

Terminix Int’l Co., No. 2:04-CV-735, 2008 WL 341363, at *4 (S.D. Ohio Feb. 6, 2008)

(distinguishing caselaw addressing differential diagnoses because the expert offered a general

causation opinion).

The source of contention is whether Dr. Tucker’s use of the word “Plaintiffs” throughout

his expert report connotes a specific causation opinion and whether Dr. Tucker must have

performed a differential diagnosis, which Defendants do not dispute that he did not perform. In

various instances he opines that “Plaintiffs’” injuries were not caused by the Ventralight ST but

by preexisting conditions or that the device could not have caused “Plaintiffs’” injuries. (ECF No.

42-1 at PageID #2342.) These statements suggest a specific causation opinion. At the same time,

Dr. Tucker uses “Plaintiffs” as a shorthand for the histology and pathology materials provided by

counsel that he reviewed for this case. For example, he states, “[i]n my review of the pathology

materials in this case, I saw no evidence of abnormal healing responses in connection with a mesh

implant procedure for any Plaintiffs.” (ECF No. 42-1 at PageID #2346.) In this context, Dr.

Tucker’s opinions appear to be general causation opinions.

Dr. Tucker’s wording is unclear, but the Court cannot say with certainty that Defendants

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could not offer Dr. Tucker’s opinion testimony in an appropriate manner to prove general

causation. At trial, Defendants must show that Dr. Tucker’s opinion is a general causation opinion

based on his review of the provided pathology and histology. Defendants purport to do so: “Dr.

Tucker’s opinions also arise out of his review and histopathologic evaluation of numerous

specimens of explanted mesh/tissue materials,” and “Dr. Tucker’s report and opinions in this case

are limited to general opinions.” (ECF No. 87 at PageID #5891–92.) In any case, Dr. Tucker

cannot opine about “Plaintiffs” as he did in his report because such statements are likely to confuse

the jury or mislead them to interpret Dr. Tucker’s testimony as specific causation evidence. And

although Dr. Tucker’s opinion is not inadmissible because he failed to conduct a differential

diagnosis, Plaintiff may cross-examine Dr. Tucker about whether he sufficiently considered other

causes of injury when he reviewed the pathologies of patients that he was presented with. 

Next, qualifications. Dr. Tucker is qualified to offer general causation opinions. Dr.

Tucker is an M.D. and Ph.D. with a medical and research specialty in pathology. (ECF No. 42-1

at PageID #2336–37.) He has ample experience with medical implantable devices and reviewing

pathology slides and specimens. (Id. at PageID #2337.) Dr. Tucker’s education and experience

qualifies him to opine on the effect of the mesh devices on human tissues, specifically whether the

tissues contained evidence of the mechanisms that caused Plaintiff’s injuries or the injuries

themselves, including poor tissue integration, degradation, mesh contraction, biocompatibility,

adhesions, etc. E.g., In re Davol, Inc./C.R. Bard, Inc., Polypropylene Hernia Mesh Prods. Liab.

Litig., 2020 WL 6605612, at *9 (S.D. Ohio Sept. 11, 2020) (concluding that medical doctors, i.e.

those who or not engineers or biochemists, may be qualified “to opine on how the product reacts

inside the body”). Because Dr. Tucker is qualified to opine on the reaction of tissues to mesh

devices from a pathology perspective, Plaintiff’s arguments that Dr. Tucker’s lack of clinical

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experience renders him unqualified are unpersuasive. (ECF No. 104 at PageID #7182–83.)

2. FDA opinions

Plaintiff argues that Dr. Tucker’s opinions related to FDA approval and clearance of the

Ventralex device and the Prolene suture are inadmissible under Federal Rule of Evidence 403 and

that any representations that a device is safe because it was approved by the FDA via the 510(k)

premarket notification process is unlawful under 21 C.F.R. § 807.97. (ECF No. 42 at PageID

#2328–29.) The Court agrees that Dr. Tucker may not offer these opinions, but on different

grounds. Dr. Tucker’s opinions are irrelevant and inadmissible character evidence.

Opinions related to the Ventralex device and Prolene sutures are irrelevant, and Defendants

agree. (ECF No. 87 at PageID #5892.) Neither is a predicate device to the Ventralight ST or

directly connected to the Ventralight ST, such as serving as a component part. Although it appears

that the Prolene suture is also made of polypropylene, there is no indication that the Prolene suture

is a component part of the Ventralight ST or otherwise directly connected to the Ventralight ST. 

Dr. Tucker’s discussion of the Ventralex’s 510(k) clearance also focused on the Ventralex’s

expanded polytetrafluoroethylene ring—a feature that the Ventralight ST does not have. (ECF

No. 42-1 at PageID #2339–40.) Therefore, evidence that the Ventralex received 510(k) clearance

is irrelevant to the triable issues in this case, including the reasonableness of Defendants’ conduct

and knowledge regarding the Ventralight ST. 

Even though Defendants appear to concede that these opinions are irrelevant, they also

argue that Dr. Tucker’s opinions related to the Ventralex device and Prolene sutures are “probative

on issues of standard of care and the reasonableness of [Defendants’] actions.” (ECF No. 87 at

PageID #5893.) This is improper propensity evidence. In this MDL, evidence related to FDA

compliance of other devices is impermissible character or propensity evidence under Federal Rule

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of Evidence 404(b) if offered to prove FDA compliance with the Ventralight ST. In re Davol,

Inc./C.R. Bard, Inc., Polypropylene Hernia Mesh Prods. Liab. Litig. --- F. Supp. 3d ----, Nos. 2:18-

md-2846, 2:18-cv-1509, 2021 WL 81821, at *3, 6–7 (S.D. Ohio Jan. 11, 2021). Defendants cannot

rely on the premarket approval of other devices, particularly where the devices are not predicates

to or components of the Ventralight ST, to demonstrate that Defendants satisfied the standard of

care when designing and marketing the Ventralight ST.

Defendants also state that Dr. Tucker’s suggestions that “the FDA considers safety and

efficacy of products submitted through the 510(k) process . . . aligns with recognized FDA

guidance and legal principles.” (ECF No. 87 at PageID #5892.) Evidence of the 510(k) process

for the Ventralight ST is admissible in this case because it is part of the story of the Ventralight

ST, but “[n]o experts will be permitted to opine on the background or legal meaning of the

process.” 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 6603657, at *8 (S.D. Ohio Oct. 20, 2020). 

3. Pore size opinions

Next, Plaintiff argues that Dr. Tucker’s opinion that there is a lack of consensus about how

to measure the pore size of mesh devices is unreliable, that he is unqualified to offer this opinion,

and that this opinion is excludable under Rule 403. (ECF No. 42 at PageID #2329; ECF No. 104

at PageID #7182). The Court disagrees because the opinion that Dr. Tucker actually offers, as

opposed to Plaintiff’s characterization of his opinion, is not misleading and is reliable, and he is

qualified to offer it.

As an initial matter, Plaintiff misconstrues Dr. Tucker’s pore size opinion. Dr. Tucker

opines that there are different methods for measuring pore size and that the FDA has not selected

a standard method for measuring pore size, leading to inconsistencies in medical and scientific

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literature discussing pore size. (ECF No. 42-1 at PageID #2351–52; ECF No. 42-4 at PageID

2417.) Plaintiff characterizes Dr. Tucker’s opinion as one that “the only testing that should be

conducted . . . is the testing required by the FDA,” and that the FDA has determined that there is

no need for a standard measure of more size. (ECF No. 42 at PageID #2329–30.) This is simply

not borne out by Dr. Tucker’s report or testimony. Dr. Tucker refused during testimony to opine

whether it was appropriate for companies to go beyond the requirements of the 510(k) rules and

conduct additional testing on pore size. (ECF No. 42-4 at PageID #2417–18.) Plaintiff also argues

that Dr. Tucker cannot offer a reliable opinion “on the most accurate way to measure pore size.”

(ECF No. 104 at PageID #7182.) But the point of his opinion is that there is no consensus on how

to measure pore size in mesh devices. Accordingly, Plaintiff’s arguments that Dr. Tucker’s

opinion is misleading and thus inadmissible under Rule 403 are unpersuasive. 

Dr. Tucker’s opinion that there is no consensus in the literature regarding pore size

measurement is reliable. Dr. Tucker reviewed medical literature to reach this conclusion. (ECF

No. 42-1 at PageID #2325 &n.4; #2352 & n.7.) Because this opinion is about a lack of consensus

in medical literature (ECF No. 42-1 at PageID #2351), the most reliable basis for that opinion is a

review of the literature, see In re Scrap Metal, 527 F.3d at 529 (noting that the reliability inquiry 

should focus on “reasonable measures of the reliability of expert testimony”). 

Plaintiff’s counterarguments go to weight, not admissibility. Plaintiff contends that Dr.

Tucker did not “process” the slides himself and that he did not review the entire explant in addition

to the slides while forming his opinions (ECF No. 104 at PageID #7184.) But this does not

demonstrate that Dr. Tucker’s opinion about the status of medical literature is unreliable. Nor does

the fact that Dr. Tucker did not create the pathology slides render unreliable Dr. Tucker’s opinion

that in light of the lack of consensus, Defendants’ measure of pore size in the Ventralight ST was

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appropriate. (ECF No. 4201 at PageID #2352.) Weaknesses in methodology are issues of weight,

not admissibility, best addressed during cross examination. Johnson, 695 F. App’x at 142 (quoting

Best, 563 F.3d at 179); see also Daubert, 509 U.S. at 596 (“Vigorous cross-examination,

presentation of contrary evidence, and careful instruction on the burden of proof are the traditional

and appropriate means of attacking shaky but admissible evidence.”).

Finally, Plaintiff also appears to argue that Dr. Tucker is unqualified to offer any pore size

opinions because “[h]e lacks first-hand knowledge of the pore sizes in mesh,” meaning he has

never explanted or implanted a mesh device. (ECF No. 104 at PageID #7182.) However, Dr.

Tucker’s opinions about pore size ultimately go to tissue integration with the surrounding the

mesh, including the ability of cells to penetrate the mesh through the pores “as part of the normal

wound healing process.” (ECF No. 42-1 at PageID #2350–52.) As a pathologist, Dr. Tucker is

qualified to offer opinions that go to tissue responses.

4. MSDS opinions

Finally, Plaintiff argues that Dr. Tucker’s opinions addressing the Marlex and Pro-Fax

polypropylene MSDSs are unreliable. (ECF No. 42 at PageID #2330–31.) In his report, Dr.

Tucker asserts that “[t]he warnings in the MSDS are not intended for the final mesh product” and

that there is no scientific support for the MSDS statement that the polypropylene is unsuitable for

permanent human implantation. (ECF No. 42-1 at PageID #2359–60.) There is no need to

consider whether these opinions are reliable because, considering the Court’s earlier ruling on the

Marlex MSDS, Dr. Tucker’s MSDS opinions are irrelevant.

Here, the Marlex MSDS is admissible as evidence of Defendants’ knowledge of the risks 

presented by polypropylene and inadmissible hearsay if offered to demonstrate that polypropylene 

was unsafe for permanent implantation in the human body. In re Davol, Inc./C.R. Bard, Inc., 2020

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WL 6603657, at *4–5. Therefore, Dr. Tucker’s opinion as to the meaning of the MSDSs, 

specifically that they are not indicative of safety for consumers or end users and that they are 

unsupported scientifically, is irrelevant to any question before the jury. 

B. James M. Anderson, M.D., Ph.D.

Dr. Anderson is a pathologist and a researcher in biomaterials, medical devices, and

prostheses. (ECF No. 399-1 at PageID #21222–23.) Plaintiff argues that (1) Dr. Anderson’s

opinions are all generally irrelevant and are all unreliable, (2) Dr. Anderson should be precluded

from offering specific causation opinions, (3) Dr. Anderson’s ST coating resorption opinion is

unreliable, (4) Dr. Anderson’s MSDS opinion is unreliable, and (5) Dr. Anderson is unqualified to

offer opinions about surgical techniques. Part of Dr. Anderson’s ST coating resorption opinions

and his MSDS opinions are inadmissible.

1. General relevance and reliability

Plaintiff argues that all of Dr. Anderson’s opinions are irrelevant because Dr. Anderson’s

opinions relate only to the plaintiff in McCourt (ECF No. 399 at PageID #21209; ECF No. 418 at

PageID #22216) and that all are unreliable because Dr. Anderson did not specify his methodology

(ECF No. 418 at PageID #22216). The Court disagrees; Dr. Anderson offers relevant general

opinions in his report, i.e. opinions that are not limited to Mr. McCourt, and it is premature to

address Plaintiff’s general reliability arguments.

At best, Plaintiff demonstrates doubt regarding whether Dr. Anderson’s opinion is limited 

to Mr. McCourt, and doubt about the admissibility of an expert’s testimony must be resolved in 

favor of admissibility. See Jahn, 233 F.3d at 388. As Plaintiff points out, Dr. Anderson’s

testimony during his deposition about the scope of his opinions is admittedly contradictory. He

first stated that his opinions “refer to Mr. McCourt’s case.” (ECF No. 399-2 at PageID #21273.) 

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Then Dr. Anderson explained, “Well, no. I mean, Mr. McCourt received [the] Ventralight ST. 

My opinion also speaks to the Ventralight ST.” (Id.) But when counsel asked, “So your report

contains all your opinions in the cases in which you were disclosed this litigation,” Dr. Anderson

replied, “No, they refer to the McCourt case only.” (Id. at PageID #21274.) However, Dr.

Anderson’s expert report unambiguously contains relevant general opinions, such as that

polypropylene is biocompatible and that the Ventralight ST had adequate pore size for proper

tissue integration. (ECF No. 399-1 at PageID #21225–300.) Moreover, Defendants have been

consistent in their position that Dr. Anderson will be offered only as a general witness. (ECF No.

409 at PageID #21477.) Dr. Anderson’s report tips the scales in favor of admission of his opinions

at this time, although some of his testimony may be an appropriate topic for cross examination.2

Plaintiff also argues that Dr. Anderson’s “application of Plaintiff McCourt’s pathology to

the Johns case is . . . irrelevant.” (ECF No. 399 at PageID #21212.) But Dr. Anderson’s review

of Mr. McCourt’s pathology is relevant to the extent Dr. Tucker’s relevant, general Ventralight ST

opinions draw on his review of Mr. McCourt’s pathology. Importantly, though, Dr. Tucker may

not refer to Mr. McCourt as a plaintiff in this MDL; in this context, Mr. McCourt’s pathology is

simply another data point. Defendants have stated that Dr. Anderson will not specifically mention

Mr. McCourt. (ECF No. 409 at PageID #21483.)

Finally, the Court cannot constructively address Plaintiff’s argument that Dr. Anderson’s

opinions are generally unreliable. Plaintiff asserts tersely in his reply brief that “Defendants do

not explain in their Opposition what Dr. Anderson’s methodology was in formulating any of his

2 Plaintiff claims here that Dr. Anderson’s report is a recitation of his opinions in the transvaginal 

pelvic mesh MDL and that he spent too few hours forming his opinions in this case. (ECF No. 399 at 

PageID #21210.) Dr. Anderson may draw on his work from previous litigation to form his opinions—if 

his opinions are otherwise reliable. See 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 *20 (S.D. Ohio Sept. 1, 

2020). That Dr. Anderson relies heavily on his previous litigation experience goes to the weight of the 

expert testimony, which is an issue for the jury. These issues can be addressed during cross examination. 

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opinions nor do they provide the general framework he used in formulating his opinions.” (ECF

No. 418 at PageID #22216.) Defendants have not had the opportunity to respond to Plaintiff’s

broader reliability argument because it was not raised until his reply brief. Therefore, the Court

declines to address this argument before trial, without the benefit of developed argument from both

sides. Because Plaintiff specifically argues that Dr. Anderson’s ST coating resorption and MSDS

opinions are unreliable, the Court addresses these particular reliability issues infra.

2. Specific causation opinions

Next, Plaintiff contends that Dr. Anderson cannot offer specific causation opinions. (ECF

No. 399 at PageID #21215–16.) Defendants confirm that they do not intend to have Dr. Anderson

offer specific causation opinions (ECF No. 409 at PageID #21477), which Plaintiff acknowledges

(ECF No. 399 at PageID #21215.) Accordingly, this argument is moot.

3. ST coating resorption opinions

Next, Plaintiff argues that Dr. Anderson’s opinions related to the window of time in which

the ST coating was resorbed are irrelevant and unreliable. (ECF No. 399 at PageID #21210.) Dr.

Anderson’s opinions about the resorption of the ST coating are relevant, and his opinion that the

ST coating performed as designed based on his visual examination of Mr. McCourt’s slides is also

reliable. However, his opinions about the mindset of the pathologist who created Mr. McCourt’s

pathology slides and the inferences he draws from those opinions are unreliable.

As a preliminary matter, the parties disagree about the precise opinion that Dr. Anderson

offers. Plaintiff focuses on Dr. Anderson’sstatement that the Ventralight ST’s ST coating resorbed

within 28 days (ECF No. 399 at PageID #21210–12), and Defendants point to his statement that

the Ventralight ST behaved as it should by preventing and minimizing adhesions (ECF No. 409 at

PageID #21485.) After reviewing his testimony, it is clear that Dr. Anderson referenced the 28-

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day figure only because Plaintiff’s counsel asked him about how an animal study affected Dr.

Anderson’s ST coating opinion. (ECF No. 409-4 at PageID #21616–18.) Dr. Anderson explained

in the first instance that the animal study “confirmed my opinion about the resorption behavior in

vivo of the Ventralight ST,” specifically that “the device behaved as designed with minimal to no

adhesions present.” (Id. at PageID #21617.) Thus, the Court treatsthisstatement as Dr. Anderson’s

opinion for the purposes of this analysis.3 

First, relevance. Dr. Anderson’s ST coating resorption opinions are relevant to Plaintiff’s

theory of injury—that the ST coating resorbed too quickly once implanted in Plaintiff, exposing

bare polypropylene. In re Davol, Inc./C.R. Bard, Inc., Polypropylene Hernia Mesh Prods. Liab.

Litig., --- F. Supp. 3d. ----, Nos. 2:18-md-2846, 2:18-cv-01509, 2021 WL 486425, at *10 (S.D.

Ohio Feb. 10, 2021). So long as Defendants offer Dr. Tucker’s opinions as general opinions about

the Ventralight ST, they are relevant even if they draw on the pathology from Mr. McCourt. Supra,

Part III.B.1. And again, Defendants have stated that Dr. Anderson will not specifically mention

Mr. McCourt. (ECF No. 409 at PageID #21483.) 

Second, reliability. Dr. Anderson’s ST coating resorption opinions are partly—but not

all—impermissible speculation. Although “[t]rained experts commonly extrapolate from existing

data . . . a Court may conclude that there is simply too great an analytical gap between the data and

the opinion proffered.” Gen. Elec. Co. v. Joiner, 522 U.S. 136, 146 (1997); Mitchell v. City of

3 Additionally, Plaintiff argues that Dr. Anderson’s ST coating opinion was previously 

undisclosed. (ECF No. 399 at PageID #21210.) If Plaintiff sought to exclude this opinion because

Defendants did not fulfill their duty under Federal Rule of Civil Procedure 26(a)(2)(B) to produce a 

complete expert report or Rule 26(e)(2) to supplement the report in light of Dr. Anderson’s deposition

testimony, the proper course of action was to file a motion to strike under Federal Rule of Procedure 37. 

See, e.g., In re Davol, Inc./C.R. Bard, Inc., Polypropylene Hernia Mesh Prods. Liab. Litig., Nos. 2:18-

cv-01509, 2:18-cv-00915, 2:18-cv-01011, 2:18-cv-01320, 2:18-cv-01443, 2:18-cv-01022, 2020 WL 

8707603 (S.D. Ohio Apr. 16, 2020) (granting in part Plaintiff’s motion to strike Dr. Badylak’s previously 

undisclosed opinion). The Court declines to consider excluding Dr. Anderson’s ST coating opinion as a 

previously undisclosed opinion without the opportunity for full consideration of the issue.

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Warren, 803 F.3d 223, 230–31 (6th Cir. 2015). Such is the case here. Dr. Anderson explained

that because Mr. McCourt’s slides “had no mesh,” “the pathologist did not identify anything

pathological with that specimen requiring him or her to submit tissues for slide preparation to

identify any pathology.” (ECF No. 399-2 at PageID #21266.) He opined that the “absence” of the

mesh “is medical evidence that that pathologist did not find anything wrong with that product, and

turned to submitting small bowel sections which were in the slide, but there was no indication of

any adhesions in those tissue sections.” (Id. at PageID #21266–67.) Dr. Anderson cannot

speculate about the mindset of the pathologist that created the slides, including what the pathologist

identified or did not identify, and especially whether the pathologist found anything “wrong” with

the explanted Ventralight ST. E.g., In re Rezulin Prods. Liab. Litig., 309 F. Supp. 2d 531, 547

(S.D.N.Y. 2004) (concluding that expert testimony “on the intent, motives or states of mind of

corporations, regulatory agencies and others have no basis in any relevant body of knowledge or

expertise”); In re Fosamax Prods. Liab. Litig., 645 F. Supp. 2d 164, 192 (S.D.N.Y. 2009).

However, Dr. Anderson’s opinion that the Ventralight ST prevented adhesions based on

his visual examination of the slides, specifically his conclusion that no adhesions were present on

the slides, is a reliable method of analysis given Dr. Anderson’s expertise as a pathologist. (ECF

No. 425 at PageID #22501 (“[I]n other mesh litigation, courts have expressly rejected arguments

that visual observations . . . are unreliable methods.”); see also In re Ethicon, Inc., Pelvic Repair

Sys. Prod. Liab. Litig., No. 2:12-CV-4301, 2014 WL 186872, at *23 (S.D.W. Va. Jan. 15, 2014). 

Accordingly, this part of Dr. Anderson’s ST coating resorption opinion is admissible.

Neither Plaintiff’s nor Defendants’ arguments to the contrary alter this conclusion. 

Plaintiff largely focuses on Dr. Anderson’s speculation about the pathologist’s mindset in creating

the slides (ECF No. 399 at PageID #21211, 21213), but this speculation has no impact on Dr.

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Anderson’s visual analysis that there were no adhesions in the pathology slides. Plaintiff also

argues that Dr. Anderson’s opinion is irrelevant because Dr. Anderson never connected his review

of Mr. McCourt’s slides to Plaintiff’s case. (Id. at PageID #21212.) However, Dr Anderson does

not need to supply every link in the chain of Plaintiff’s theory of the case for his opinion to be

relevant. 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) (“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.”).

On the other side, defendants argue that Dr. Anderson is not speculating due to his ample

experience. (ECF No. 409 at PageID #21482, 21484.) Dr. Anderson’s experience speaks to his

qualifications, not the reliability of his opinion. And “‘no matter how good’ experts’ ‘credentials’

may be, they are ‘not permitted to speculate.’” Tamraz v. Lincoln Elec. Co., 620 F.3d 665, 671

(6th Cir. 2010) (quoting Goebel v. Denver & Rio Grande W. R.R. Co., 215 F.3d 1083, 1088 (10th

Cir. 2000)). Defendants claim that the Court found Dr. Babensee’s and Dr. El-Ghannam’s general

causation opinions reliable based on their experience (ECF No. 409 at PageID #21484), but in both

of these instances the Court discussed their experience in relation to their qualifications—not the

reliability of their opinions. 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 *24–25 (S.D. Ohio Sept. 

1, 2020) (“Dr. Babensee is well-qualified based on her knowledge, education, and experience as a 

biomaterials scientist to offer general opinions of the biological effects of the Ventralight ST mesh 

on the human body.”); 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 *7 (S.D. Ohio Sept. 10, 2020)

(concluding that Dr. El-Ghannam was qualified to offer his opinion and that even though his 

“experience is due to his work as an expert in other MDLs involving Bard’s polypropylene devices 

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does not warrant exclusion of his opinions, as long as the opinions are sufficiently reliable” 

(emphasis added).)

4. MSDS opinions

Plaintiff challenges part of Dr. Anderson’s report in which he addresses the MSDS as

unreliable. (ECF No. 399 at PageID #21216.) In his report, Dr. Anderson characterizes the

MSDSs as “safety documentsfor employees who handle raw materials” that “provide occupational

exposure warnings.” (ECF No. 399-1 at PageID #21247.) He also notes that the MSDSs do not

indicate what testing and/or data supports the warning that polypropylene should not be used for

permanent human implantation. (Id.) There is no need to address the reliability of Dr. Anderson’s

MSDS opinion because it is irrelevant and inadmissible. The Marlex MSDS is only admissible as 

evidence of Defendants’ knowledge and is inadmissible hearsay if offered to demonstrate that 

polypropylene was unsafe for permanent implantation in the human body. In re Davol, Inc./C.R.

Bard, Inc., 2020 WL 6603657, at *4–5. Therefore, Dr. Anderson’s opinion regarding the meaning 

of MSDSs is irrelevant to what Defendants actually thought the MSDS meant or what they 

otherwise knew about the risks of the polypropylene at the time the Ventralight ST was designed 

and marketed. Supra, Part III.A.4. 

5. Surgical technique opinions

Finally, Plaintiff argues that Dr. Anderson is unqualified to offer any opinions about

surgical techniques used to implant the Ventralight ST because he is not a general surgeon and

does not practice surgery. (ECF No. 399 at PageID #21216.) Defendants counter that Dr.

Anderson is qualified to offer opinions about the impact of implantation technique on the body’s

response to implantation of the device. (ECF No. 409 at PageID #21489.) Dr. Anderson is

qualified to opine on the impact of surgical technique on the body’s tissue response.

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As a pathologist, Dr. Anderson is qualified to testify about the effects of a particular

surgical technique for placement of a mesh device on the body’s tissue response. Dr. Anderson

has forty-five years of experience studying biomaterials and medical devices, and their

biocompatibility, tissue responses, and foreign body reactions. (ECF No. 399-1 at PageID

#21223.) In his deposition, he explained that part of his study of biomaterials and medical devices

involves animal implantations. (ECF No. 399-2 at PageID #21275.) In Dr. Anderson’s report, he

discusses factors that affect wound healing—a tissue response—including “physician factors.” 

(ECF No. 399-1 at PageID #21240.) He explains that a surgeon’s skills and training affect wound

healing. (Id. at PageID #21241.) Dr. Anderson also explains that “appropriately implanted” mesh

devices “lead[ ] to a decrease in the thickness of the mesh within the fibrous capsule as well as a

decrease in the thickness of the fibrous capsule,” which is a more positive outcome. (Id. at PageID

#21245.) The impact of surgical techniques on tissue response is within his pathology expertise.

Plaintiff argues that because Dr. Anderson is not a surgeon, he cannot offer general surgery

technique opinions. (ECF No. 399 at PageID #21217.) The Court generally agrees that Dr.

Anderson is unqualified to offer surgery opinions from the perspective of the implanting surgeon. 

However, Dr. Anderson does not offer such an opinion; he opines on the impact of surgical

methods from a pathology perspective. Plaintiff does not appear to dispute Dr. Anderson’s

qualifications as a pathologist. Indeed, Defendants expressly represent that they do not intend to

have Dr. Anderson offer any surgery opinions. (ECF No. 409 at PageID #21489.)

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IV. Conclusion

For these reasons, Plaintiff’s motion to exclude Dr. Tucker’s opinions and testimony (ECF 

No. 42) is GRANTED IN PART AND DENIED IN PART, and Plaintiff’s motion to exclude 

Dr. Anderson’s opinions and testimony (ECF No. 399) 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

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