Shana Hargrove, As Power of Attorney for Kevin Welch v. Meds Tar Washington Hospital Center , Et Al .

United States Court of Appeals
FOR THE DISTRICT OF COLUMBIA CIRCUIT
Argued April 13, 2026 Decided August 21, 2026
No. 25-7129
S HANA HARGROVE, AS POWER OF ATTORNEY FOR KEVIN
WELCH,
APPELLANT
v.
M EDS TAR WASHINGTON HOSPITAL C ENTER , ET AL .,
APPELLEES
Appeal from the United States District Court
for the District of Columbia
(No. 1:23-cv-03381)
Governor E. Jackson III argued the cause for appellant.
On the briefs was Kim Parker.
Peter R. Naugle argued the cause for appellees. With him
on the brief was Derek M. Stikeleather. Donna Sturtz entered
an appearance.
Before: M ILLETT, W ILKINS and KATSAS , Circuit Judges.
Opinion for the Court filed by Circuit Judge WILKINS .

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WILKINS , Circuit Judge: This appeal arises from a
medical malpractice action brought on behalf of Kevin Welch
against MedStar Washington Hospital Center, Dr. Stephen
Luczycki, Dr. Maxwell Hockstein, and Dr. Kaitlyn Dunphy
(collectively, “the Hospital”). The Complaint alleged that
Intensive Care Unit (“ICU”) providers failed to implement
timely stroke-mitigation measures following Mr. Welch’s
emergency Type A aortic dissection repair, resulting in
permanent neurological injury. The District Court excluded
the causation testimony of Mr. Welch’s experts under Federal
Rule of Evidence 702 and Federal Rules of Civil Procedure
26(a)(2) and 37(c)(1). Since medical malpractice suits brought
in the District of Columbia require expert testimony to
establish causation and the only proffered causation experts’
testimony was deemed inadmissible, the District Court granted
summary judgment in favor of the Hospital. Mr. Welch’s
appeal challenges the exclusion of the testimony and the grant
of summary judgment.
I.
A.
On June 14, 2022, 42-year-old Kevin Welch presented
with severe chest pain and was diagnosed with an ascending
aortic dissection requiring emergency surgery. App.012–14.
The operation included six different procedures, with the
primary procedure being a Type A aortic dissection (“TAAD”)
repair. App.014. The procedures were completed “without any
complication[s].” Id. Mr. Welch was intubated and transferred
to the ICU in “critical but stable condition” under the care and
supervision of ICU attending physician Dr. Hockstein, critical
care physician Dr. Luczycki, as well as surgical ICU rotating
resident Dr. Dunphy. Id.

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On June 15, Mr. Welch woke up confused and
disoriented—not fully understanding where he was or why he
was in the hospital. Id. By June 16, his physicians expressed
concern about possible changes in brain activity. Id.; see also
App.041. The next day, after Mr. Welch began “exhibiting
severe bi-lateral lower extremity weakness,” he underwent a
neurology consultation. App.015. Following the examination,
and due to a “concern for spinal cord infarct” (i.e., a stroke that
occurs in the spinal cord), neurology recommended performing
magnetic resonance imaging (“MRI”) and a head computed
tomography (“CT”); however, the MRI was not performed
because Mr. Welch was showing improvement and because of
“safety reasons.” Id.; see also App.041. According to the
Hospital, the MRI was deferred because the procedure required
transport outside the ICU, reduced monitoring, and removal of
epicardial lead wires needed for blood-pressure management—
all of which were not considered safe unless Mr. Welch was at
a certain level of stability. Appellees’ Br. 4; App.160. Over
the next few days, the MRI was deferred again for safety
reasons and because Mr. Welch’s blood pressure was “under
better control.” App.016.
The MRI performed on June 22 indicated that Mr. Welch
had suffered a stroke. App.016–17. Mr. Welch alleges that,
prior to June 21, no actions were taken “to increase [his] blood
pressure to mitigate the risk of neurological insult,” nor did the
Hospital consider “the placement of a lumbar drain to mitigate
the risk of neurological insult” prior to June 22. App.041
(citing App.017).
A little over two weeks later, Mr. Welch was transferred
to MedStar National Rehabilitation Hospital for treatment of
residual functional impairments and was discharged in
September with instructions to obtain occupational, physical,
and speech therapy. App.017.

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Throughout the litigation, Mr. Welch maintained that he
“continues to struggle with executive functioning, apathy, and
visual-spatial issues.” App.042; see also Appellant’s Br. 5
(quoting a letter stating that Mr. Welch is “permanently
disabled”). The Hospital responds that the record reflects
substantial improvement in Mr. Welch’s physical condition,
including examinations showing “full range of motion and
strength in all extremities,” no focal deficits, and an ability to
“independently perform all of his activities of mobility and
daily living.” Appellees’ Br. 5. Further, the Hospital contends
that the reference to “permanent[] disab[ility]” concerns
“cognitive issues,” rather than the lower-extremity weakness
on which Mr. Welch principally bases his medical-malpractice
claims. Id. at 5–6 (emphasis in original). In support of this
contention, the Hospital notes that, in an examination note by
one of Mr. Welch’s physicians, Mr. Welch exhibited “full
range of motion and strength in all extremities.” Id. at 5.
B.
Ms. Shana Hargrove, as power of attorney for Mr. Welch,
filed suit in District Court in November 2023, alleging that the
Hospital negligently failed to recognize, diagnose, and treat
Mr. Welch’s strokes. See, e.g., App.001, 009–27. Mr. Welch
specifically asserts that the Hospital “prolonged the
performance of [an MRI],” “fail[ed] to take steps to control
[his] blood pressure,” and “fail[ed] to document and/or
otherwise place a lumbar drain,” all of which exacerbated the
consequences of his stroke. App.019–21.
At the close of discovery, the Hospital filed two motions
in limine to exclude the testimony of two of Mr. Welch’s
experts, Dr. Ahmad Elakil and Dr. Peter Schulman, addressed
to proximate causation and damages. Mr. Welch opposed both
motions. Following responses from Mr. Welch, the Hospital

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moved for summary judgment on the grounds that if Dr. Elakil
and Dr. Schulman’s testimony were excluded, Mr. Welch
would be unable to successfully prove his medical malpractice
claims. On August 7, 2025, the District Court granted the
Hospital’s motions in limine, excluding Dr. Elakil and Dr.
Schulman’s testimony under Federal Rule of Evidence 702 as
well as Federal Rules of Civil Procedure 26(a)(2) and 37(c)(1),
respectively, and granted the Hospital’s motion for summary
judgment. See, e.g., App.040–59. Mr. Welch filed this timely
appeal on September 5, 2025.
II.
We have jurisdiction to review this case under 28 U.S.C.
§ 1291.1 And we begin our review with Mr. Welch’s
contention that the District Court improperly excluded Dr.
Elakil’s expert testimony under Federal Rule of Evidence 702.
We disagree and sustain the District Court’s decision to
exclude Dr. Elakil’s testimony.
1 The District Court had jurisdiction over this case under 28 U.S.C.
§ 1332(a). The Complaint lists Medstar Washington Hospital Center
as the defendant. However, Medstar Washington Hospital Center is
only a trademark name. See United States Patent and Trademark
Office, uspto.gov, Trademark Serial Number, 76296151
(Registration Date 2002-10-08; Updated 2023-03-14). The owner of
the trademark is Washington Hospital Center Corporation. Id.
Washington Hospital Center Corporation is a Delaware Corporation
registered to do business in the District of Columbia under the trade
name MedStar Washington Hospital Center, and with a principal
place of business in Washington D.C. Therefore, for purposes of
diversity jurisdiction, Washington Hospital Center Corporation is a
citizen of Delaware and the District of Columbia. See 28 U.S.C. §
1332(c)(1). In addition, Dr. Luczycki is a citizen of Virginia, and
Doctors Dunphy and Hockstein are citizens of the District of
Columbia. ECF No. 8. Since Mr. Welch is a citizen of Maryland,
diversity jurisdiction is proper in this case.

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A.
We review a district court’s decision to admit or exclude
expert testimony under Daubert v. Merrell Dow Pharms., Inc.,
509 U.S. 579, 597 (1993), for abuse of discretion. Kumho Tire
Co., Ltd. v. Carmichael, 526 U.S. 137, 142 (1999).
We “must … afford trial judges great discretion” in admitting
or excluding expert testimony. United States v. Morgan, 45
F.4th 192, 200 (D.C. Cir. 2022) (quoting United States v. Day,
524 F.3d 1361, 1367 (D.C. Cir. 2008)).
Federal Rule of Evidence 702 vests district courts with a
“gatekeeping role” to “ensur[e] that an expert’s testimony both
rests on a reliable foundation and is relevant.” Daubert, 509
U.S. at 597. Under Rule 702, a witness may be qualified as an
expert based on “knowledge, skill, experience, training, or
education.” F ED. R. EVID. 702. Before admitting Dr. Elakil’s
expert testimony, the District Court was required to determine
that the proponent had demonstrated, by a preponderance of the
evidence, that the testimony would be (a) “help[ful] [to] the
trier of fact to understand the evidence or to determine a fact in
issue,” (b) “based on sufficient facts or data,” (c) “the product
of reliable principles and methods,” and (d) “reflect[] a reliable
application of the principles and methods to the facts of the
case.” Id.; F ED. R. EVID. 702 advisory committee’s note to
2023 amendment2 (citing Bourjaily v. United States, 483 U.S.
2 Effective December 1, 2023, Federal Rule of Evidence 702 was
amended to clarify that expert testimony is admissible only if “the
proponent demonstrates to the court that it is more likely than not
that” each of the Rule’s four admissibility requirements is satisfied.
FED. R. EVID. 702 (2023). The amendment also modified subsection
(d) to require that “the expert’s opinion reflects a reliable application
of the principles and methods to the facts of the case.” Id. The
Advisory Committee explained that the amendment was intended to
correct some court decisions incorrectly holding “that the critical

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171, 175 (1987)). The Supreme Court in Daubert explained
that the requirements of relevance and reliability must be
“established by a preponderance of proof” pursuant to Rule
104(a). 509 U.S. at 592 n.10. We likewise applied that
standard before the 2023 amendment made it explicit. Meister
v. Med. Eng’g Corp., 267 F.3d 1123, 1127 n.9 (D.C. Cir. 2001)
(quoting Daubert, 509 U.S. at 592 n.10). The amendment
therefore confirmed, rather than altered, our existing burden-
of-proof rule.
In assessing the admissibility of expert testimony, courts
may consider a myriad of factors “includ[ing] whether the
expert’s theory or technique (i) can be (and has been) tested,
(ii) has been subjected to peer review and publication, (iii) has
a high known or potential rate of error, and (iv) enjoys general
acceptance within a relevant scientific community.” Morgan,
45 F.4th at 200. District courts have “considerable leeway”
both in determining how to assess reliability, the final prong of
Rule 702, and in reaching their “ultimate conclusion[s]” on that
question. Kumho Tire, 526 U.S. at 152.
B.
The District Court held that the grounds underlying Dr.
Elakil’s causation opinions did not reflect the “level of
intellectual rigor” required under Federal Rule of Evidence 702
questions of the sufficiency of an expert’s basis, and the application
of the expert’s methodology, are questions of weight and not
admissibility.” FED. R. EVID. 702 advisory committee’s note to 2023
amendment. Because the parties do not ask us to define the precise
point at which a particular challenge concerns admissibility rather
than weight, and resolution of that question is unnecessary here, we
decline to address it. See Margolin v. Nat’l Ass’n of Immigr. Judges,
146 S. Ct. 1285, 1288 (2026) (per curiam); see also Clark v. Sweeney,
607 U.S. 7, 9–10 (2025) (per curiam).

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and therefore excluded the testimony.
App.051 (citation modified). Though the District Court
appears to have placed undue emphasis on Dr. Elakil’s clinical
experience, the District Court’s analysis as a whole falls well
within the scope of its discretion. Accordingly, we affirm.
1.
First, the District Court held that the threshold causation
question in the case was whether “stroke mitigation procedures
following the TAAD repair would have improved plaintiff’s
outcomes” because “plaintiff’s recovery from the TAAD repair
is inseparable from the causation analysis.” App.047–48
(emphasis in original). The District Court then explained it
would evaluate whether Dr. Elakil had “good grounds” to opine
on this question. Id. (quoting Daubert, 509 U.S. at 590). While
Mr. Welch takes issue with the District Court’s
characterization of his theory of the case, neither party
challenges the District Court’s framing of the causation issue.
Appellant’s Br. 15–16; Appellees’ Br. 20. Finding no issues,
we will uphold this framing and continue with our analysis.
2.
Dr. Elakil, a board-certified neurosurgeon, opined that
delays in responding to Mr. Welch’s post-operative
neurological symptoms caused or exacerbated his lower-
extremity weakness as well as bowel and bladder dysfunction
such that his weakness is “now permanent … instead of likely
temporary.” App.345, 351–52, 459. In particular, he testified
that better blood pressure management and placing a lumbar
drain after the onset of symptoms might have resulted in a
“complete resolution” of those symptoms or, at least, greater
improvement than what Mr. Welch ultimately experienced.
App.449, 454, 460.

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Dr. Elakil based that opinion principally on medical
records from Mr. Welch’s 2022 hospitalization and the period
immediately following his surgery, App.345, 437, his
professional training and experience, App.345, and four
medical articles, only one of which concerned a TAAD repair
and post-operative spinal cord injuries. See, e.g., App. 050–51,
439 (explaining which articles were relied on for which
components of his testimony). Dr. Elakil also testified that he
recalled placing lumbar drains in patients who had undergone
TAAD repairs “a few” times during his residency and once at
a hospital where he was previously employed prior to his
deposition, but he could not recall any patient who experienced
complete resolution of symptoms. App.450–52. Finally, Dr.
Elakil admitted that he failed to examine Mr. Welch or review
his medical records after 2022, including subsequent
rehabilitation or neurological reports. App.437, 440. He even
acknowledged during his deposition that, without performing a
medical examination himself, he could not determine the extent
of Mr. Welch’s current lower-extremity weakness, including
whether it was permanent or resolved. App.458–59.
3.
The District Court carefully considered the three
foundations Dr. Elakil identified as the basis for his causation
opinions: (i) his clinical experience, (ii) his review of some
medical records and the deposition transcripts in this case, and
(iii) select medical literature. App.048. Although the District
Court placed undue emphasis on Dr. Elakil’s role as a
neurosurgeon, it permissibly considered the extent to which his
clinical experience related to the specific causation question.
Ultimately, we find no error in the District Court’s
determination that Dr. Elakil’s limited medical experience,
deficient review of the medical records, and narrow set of

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literature failed to provide an adequate basis for his causation
opinions. App.051–52.
First, the District Court found Dr. Elakil’s clinical
experience deficient based on the limited number of TAAD
repairs he had performed and patients he cared for following
such repairs, as well as his role as a neurosurgeon rather than a
cardiothoracic surgeon. App.048–49. The District Court
acknowledged that expert witnesses do not need to be
specialists in a specific field to testify. However, in this case,
the District Court felt the issues were more specifically related
to cardiothoracic surgery and vascular neurology, and thus Dr.
Elakil’s specialty paired with his lack of experience “[did] not
align with the medical expertise needed to opine on the
nuanced causation questions” regarding TAAD repairs.
App.049.
We agree only in part with this aspect of the District
Court’s reasoning. We have long held that physicians are “not
incompetent to testify as an expert merely because [they are]
not [] specialist[s] in the particular field [in] which” they seek
to testify. Baerman v. Reisinger, 363 F.2d 309, 310 (D.C. Cir.
1966) (citation modified). It is entirely possible for physicians
to have sufficient experience with the surgery at issue without
practicing in a field that routinely performs that surgery, or
without having performed the surgery a great number of times.
Nevertheless, the District Court did not abuse its discretion in
considering Dr. Elakil’s lack of familiarity with a complicated
medical procedure as a relevant consideration, because it was
considered alongside the weightier problems of Dr. Elakil’s
deficient review of Mr. Welch’s medical records and the
substantial gaps in the medical literature on which he relies.
See Meister, 267 F.3d at 1126–32 (affirming exclusion of
expert medical testimony after considering multiple

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deficiencies in the experts’ methodologies and supporting
evidence).
Second, we find no error in the District Court’s
determination that Dr. Elakil’s conclusion—that the Hospital’s
alleged negligence caused Mr. Welch’s deficits to become
permanent—was not “based on sufficient facts or data.”
App.050 (quoting F ED. R. EVID. 702(b)). As the District Court
explained, Dr. Elakil admitted he had neither examined Mr.
Welch himself nor reviewed Mr. Welch’s medical records after
2022, even though such records were available. App.049–50.
This is particularly significant because Dr. Elakil testified that,
“without a medical . . . examination” it would be “really hard
to say” “how much improvement [Mr. Welch] had after all
these years.” App.459. We do not hold that a medical
examination is always required before an expert may offer a
causation opinion in a medical-malpractice case. But here,
where Dr. Elakil opines specifically that Mr. Welch’s deficits
were permanent in 2024, the District Court reasonably
concluded that the opinion did not rest on “sufficient facts or
data” because Dr. Elakil had not reviewed any medical records
after 2022 and instead relied primarily on those dated records
and Mr. Welch’s own assessment of his condition to form his
opinion. App.049–50.
Finally, the District Court reasonably concluded that the
articles “do not establish that [Dr. Elakil’s] theories have been
tested, subject to peer review, or generally accepted.” App.050
(citing Morgan, 45 F.4th at 200 (explaining factors that can
inform the reliability analysis under Rule 702)). Three of the
four articles were “facially irrelevant.” App.050. And the
article with the most relevant factual parallels (i.e., a discussion
of a 77-year-old patient who underwent a TAAD repair and
suffered post-operative spinal cord injuries) did not support,
and in some respects contradicted, Dr. Elakil’s proffered

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conclusions. App.051. In the article, the treating physicians
“rejected” blood-pressure management as a means of
addressing the patient’s post-surgery complications, contrary
to Dr. Elakil’s testimony. App.050–51, 054. The article
characterized the blood pressure management interventions
that Dr. Elakil said were warranted as “unnecessary.”
See App.651. Dr. Elakil testified that “many articles in the
literature . . . say[] that the patient[s] have complete resolution
[of symptoms] day one after placement of a lumbar drain.”
App.449. However, the article he relied on stated that the
lumbar drain placed at the “onset of symptoms” provided only
“partial benefit[s]” to the patient. App.651. It is also unclear
what “benefits” the patient experienced. Ultimately, Dr. Elakil
failed to provide any articles that supported the methodologies
underlying his testimony.
Accordingly, the District Court did not abuse its
discretion in deeming Dr. Elakil’s testimony on what caused
the permanency of Mr. Welch’s injuries to be unreliable within
the meaning of Federal Rule of Evidence 702 and our
precedents. We affirm the District Court’s exclusion of Dr.
Elakil’s causation testimony.
III.
We now turn to Mr. Welch’s contention that the District
Court erred in precluding Dr. Schulman’s causation testimony.
Mr. Welch argues that the District Court abused its discretion
by excluding Dr. Schulman’s testimony because he disclosed
him as a causation expert and the Hospital was prepared to
question him about causation during his deposition. We find
no merit in Mr. Welch’s arguments.

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A.
We review the District Court’s evidentiary rulings under
an abuse of discretion standard. Carey Canada, Inc. v.
Columbia Cas. Co., 940 F.2d 1548, 1559 (D.C. Cir. 1991).
Under Federal Rule of Civil Procedure 26(a)(2), a party
must disclose its expert witnesses to the opposing parties, and
each expert must provide a written report that includes “a
complete statement of all opinions the witness will express and
the basis and reasons for them,” along with “the facts or data
considered by the witness in forming them.” F ED. R. C IV. P.
26(a)(2) (emphasis added). When a party fails to make the
required expert disclosure, that party “is not allowed to use that
. . . witness to supply evidence on a motion, at a hearing, or at
a trial, unless the failure was substantially justified or is
harmless.” F ED. R. C IV. P. 37(c)(1).
The District Court excluded Dr. Schulman’s causation
testimony because he was only disclosed as an expert on the
standard of care elements of Mr. Welch’s claims. App.053; see
also App.294–99. The District Court found that, contrary to
the requirements of Federal Rule of Civil Procedure
26(a)(2)(B), neither Mr. Welch’s expert disclosures nor Dr.
Schulman’s expert report indicate that he planned to testify
about proximate causation. App.052–53, 294–99. As the
District Court noted, it is especially telling that, during his
deposition, Dr. Schulman confirmed opposing counsel’s
characterization that he would “testify about [the] standard of
care only” and, as to “causation opinions, [he would] defer to
an expert in other areas such as neurology[.]” App.053, 074.
Since Mr. Welch offered no argument that his failure to
disclose was substantially justified or harmless, and the
Hospital explained why it was both surprised and unprepared
to examine Dr. Schulman as a potential causation expert, the

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District Court excluded the expert testimony under Rule
37(c)(1). App.053. Because Mr. Welch did not attempt to
explain to the District Court why the failure to disclose Dr.
Schulman as a causation expert was either substantially
justified or harmless, App.053, it was not an abuse of discretion
for the District Court to conclude that Mr. Welch failed to meet
his burden under Rule 37(c)(1).
Pivoting, Mr. Welch now argues that the District Court’s
initial finding that he did not disclose Dr. Schulman as a
causation expert was incorrect. Appellant’s Br. 29–30. In Mr.
Welch’s view, Dr. Schulman’s expert disclosure includes
references to causation testimony such that the Hospital was
“able to predict the scope of Dr. Schulman’s causation
testimony.” Id. at 29. Specifically, Dr. Schulman’s witness
designation states that Dr. Schulman would opine that a finding
of a hospital radiologist who read Mr. Welch’s MRI was “more
likely than not, the explanation for Mr. Welch’s ongoing lower
extremity weakness.” Id. (emphasis omitted). As further
support for his contention that the disclosure encompasses
causation opinions, Mr. Welch argues the Hospital’s deposition
questions demonstrated that it was “apprised” of his “causation
opinions.” Id.
Mr. Welch’s arguments find insufficient support in the
record or governing law and therefore fall short of
demonstrating that the District Court abused its discretion.
Based on Dr. Schulman’s own understanding of his role as an
expert witness, he was not providing a causation opinion. See
App.074. As the District Court found, there were no references
to causation in Mr. Welch’s expert designation, nor does Dr.
Schulman provide causation opinions in his expert report.
App.052; see also App.294–99. At best, Dr. Schulman’s
disclosure describes what he believed to be an implied opinion
on causation held by someone else—a hospital radiologist. The

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record citations on which Mr. Welch relies do not contradict
the District Court’s finding. Further, Mr. Welch’s contention
that opposing counsel’s ability to ask causation related
questions during Dr. Schulman’s deposition demonstrates that
his disclosure was adequate is unpersuasive. First, he cites no
authority supporting that proposition. Second, comments made
by Dr. Schulman for the first time in his deposition regarding
causation do not provide fair notice such that the Hospital had
“a reasonable opportunity to prepare.” See F ED. R. C IV. P. 26
advisory committee’s note to 1993 amendment.3
For the reasons stated above, the District Court did not
abuse its discretion in excluding Dr. Schulman as an expert
witness on the issue of causation.
IV.
Finally, we review “de novo orders granting motions to
dismiss under Rule 12(b)(6) or granting summary judgment
under Rule 56.” Goodrich v. Bank of Am., N.A., 136 F.4th 347,
353 (D.C. Cir. 2025). Summary judgment is appropriate
“against a party who fails to make a showing sufficient to
establish the existence of an element essential to that party’s
case, and on which that party will bear the burden of proof at
trial.” Celotex Corp. v. Catrett, 477 U.S. 317, 322 (1986).
Under District of Columbia law, “[t]he plaintiff in a
negligence action bears the burden of proof on three issues: ‘the
applicable standard of care, a deviation from that standard by
3 In his Reply Brief, Mr. Welch argues for the first time that the
“purpose of Rule 26(a)(2) is to prevent unfair surprise at trial” and
“to permit the opposing party” to prepare their responses and
defenses. Reply Br. 9. “But arguments raised for the first time in a
reply brief are forfeited.” United States v. Lawrence, 1 F.4th 40, 46
n.3 (D.C. Cir. 2021).

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the defendant, and a causal relationship between that deviation
and the plaintiff’s injury.’” Butera v. District of Columbia, 235
F.3d 637, 659 (D.C. Cir. 2001) (quoting Toy v. District of
Columbia, 549 A.2d 1, 6 (D.C. 1988)). District of Columbia
medical malpractice law requires expert testimony on each
element of a medical malpractice claim “except where proof is
so obvious as to lie within the ken of the average lay juror.”
Snyder v. George Washington Univ., 890 A.2d 237, 244 (D.C.
2006) (quoting Derzavis v. Bepko, 766 A.2d 514, 519 (D.C.
2000)). Mr. Welch does not dispute that an expert was required
to testify to causation in this case.4 See Appellant’s Br. 30.
Dr. Elakil and Dr. Schulman are the only expert witnesses
offered by Mr. Welch to support the causal element of his
medical negligence claims. Without their testimony, there is
no path forward for Mr. Welch to prove the highly technical
causation element. Accordingly, Mr. Welch’s “failure to offer”
essential testimony “justif[ies] the grant of summary judgment
against him.” Burke v. Air Serv. Int’l, Inc., 685 F.3d 1102,
1106 (D.C. Cir. 2012).
4 In Berk v. Choy, 607 U.S. 187 (2026), the Supreme Court held that
a state law requiring an affidavit by a medical professional attesting
to the merits of a medical malpractice claim “answer[ed] the same
question” as Federal Rule of Civil Procedure 8 and so was displaced
by Rule 8 under Erie R. Co. v. Tompkins, 304 U.S. 64 (1938). Berk,
607 U.S. at 198. Our precedent has already determined that the
District of Columbia’s rule requiring expert testimony does not run
afoul of Federal Rule of Evidence 702. Burke v. Air Serv. Int’l, Inc.,
685 F.3d 1102, 1107 (D.C. Cir. 2012). Because neither party here
has raised the Erie question in the context of Federal Rule of Civil
Procedure 56, we do not address it here. See Margolin v. Nat’l Ass’n
of Immigr. Judges, 146 S. Ct. 1285, 1288 (2026).

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* * *
Since the District Court properly excluded Dr. Elakil’s
testimony under Federal Rule of Evidence 702 and Dr.
Schulman’s testimony under Federal Rules of Civil Procedure
26 and 37, Mr. Welch lacked the required expert testimony on
causation. Therefore, the District Court properly granted
summary judgment in favor of the Hospital. We affirm.
So ordered.

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