Court Opinion

ID: 6336207
Source: CourtListenerOpinion
Date Created: 2022-04-28 22:00:19.698976+00
Date Added: 2024-06-11T09:24:09.084498
License: Public Domain

United States Court of Appeals
                     For the First Circuit

No. 20-1937

      EULALIA LÓPEZ-RAMÍREZ; LAURA CRISTINA GAUDIER-LÓPEZ,

                     Plaintiffs, Appellants,

                               v.

  DR. MARÍA M. TOLEDO-GONZÁLEZ; CENTRO MÉDICO DEL TURABO, INC.,
              d/b/a Hospital HIMA San Pablo Caguas,

                     Defendants, Appellees,

 GUSTAVO J. NOGALEZ-PÉREZ; CONJUGAL PARTNERSHIP TOLEDO-NOGALES;
 UNKNOWN MONITORING COMPANIES AND/OR UNKNOWN NEUROPHYSIOLOGICAL
 MONITORING COMPANIES A, B AND C; JOHN DOES 1, 2 AND 3; A, B AND
 C CORPORATIONS; UNKNOWN INSURANCE COMPANIES, A THROUGH H; NEXT
            STEP MEDICAL CO. INC.; BROMÉDICON, INC.,

                           Defendants.

          APPEAL FROM THE UNITED STATES DISTRICT COURT
                FOR THE DISTRICT OF PUERTO RICO

       [Hon. Raúl M. Arias-Marxuach, U.S. District Judge]

                             Before

                       Barron, Chief Judge,
              Thompson and Kayatta, Circuit Judges.

     David Efron, with whom Law Offices of David Efron, P.C. was
on brief, for appellants.
     Jeannette López de Victoria, with whom Oliveras & Ortiz, PSC
was on brief, for appellee Dr. María M. Toledo-Gonzáles.
     Roberto Ruiz Comas, with whom RC Legal & Litigation Services,
PSC was on brief, for appellee Centro Médico del Turabo, Inc.,
d/b/a Hospital HIMA San Pablo Caguas.

                         April 28, 2022
            BARRON, Chief Judge.          This appeal is from a grant of

summary judgment against Eulalia López-Ramírez ("López"), in the

medical malpractice suit that she, joined by her daughter, brought

under Puerto Rico law in the United States District Court for the

District of Puerto Rico.          The suit seeks recovery in connection

with the brain surgery that was performed on López to alleviate

her facial spasms.       We affirm.

                                        I.

            We begin with a description of the undisputed facts and

the procedural history. We then provide some of the relevant legal

background to set the stage for the analysis to follow.

                                        A.

            López had been suffering             for approximately eighteen

years    from   facial   spasms    --    specifically,    "right     hemifacial

spasms."    She had stopped responding to Botox treatment.

            To address the spasms, López visited a neurosurgeon,

Dr. Maria M. Toledo González ("Dr. Toledo"), on September 29,

2015.    Dr. Toledo recommended surgery after a "Brain MRI scan"

revealed that a blood vessel abutted López's right facial nerve.

The surgery would involve entering López's skull using a procedure

known as a "right retrosigmoid craniotomy" and then surgically

moving    the   offending   blood       vessel   away   from   the   nerve,   or

"decompressing" the nerve, in a process known as "microvascular

decompression."

                                    - 3 -
           López    consented   to    having    the   surgery    performed   at

Hospital   HIMA    (the   "Hospital").1        During   the   surgery,    which

occurred on January 26, 2016, Dr. Toledo used a process the parties

described as "neuromonitoring" to            determine, using equipment,

whether her manipulation of the nerves and blood vessels was

causing any irritation or damage to the nerves.

           Later that day, after the surgery had been completed,

López was "[b]arely able to raise [her] eyebrow" and could not

fully close her eye.        Her condition worsened until, a few days

later, Dr. Toledo confirmed that López could "not hear anything"

in her right ear, had full right facial paralysis, and was "in a

wheelchair due to lack of balance."              Further testing revealed

greater damage.

                                       B.

           On December 23, 2016, López and her daughter brought

this lawsuit in the District of Puerto Rico against Dr. Toledo,

the   Hospital,    and    various    other   defendants.        The   operative

complaint claimed that the defendants failed to provide López "with

           1The record does not contain López's written consent to
the surgery, and although the parties' experts mention a consent
form, they dispute whether that document constituted evidence of
an informed consent to the surgery.       Although the plaintiffs
referred to an alleged inadequacy in the consent in the joint
pretrial conference report, they did not advance any argument
concerning the consent in their briefing in opposition to
Dr. Toledo's motions to exclude their expert testimony and for
summary judgment.

                                     - 4 -
adequate neurological evaluation and treatment during her surgery

and stay in the hospital" or the "consultations" and "treatments"

necessary to "avoid a massive stroke," and that these failures

"constituted gross negligence."             The complaint further claimed

that the defendants "deviat[ed] from accepted medical practices"

by   "performing        surgery   without    identifying,    isolating   and

protecting the nerve and vascular tissue in the affected area," by

"fail[ing] to timely diagnose the devastating neurological damage

in process," and by "fail[ing] to provide adequate monitoring in

the process to identify the risks and multiple perforations to the

cerebral artery."

               The complaint claimed that the defendants' negligence

in providing medical care to López made them liable to her and her

daughter under Puerto Rico Laws title 31, Sections 5141 and 5142.

The complaint sought economic and non-economic damages, including

for López's "severe physical and emotional pain and suffering,"

and her daughter's "severe emotional suffering."2

                                      C.

           To establish a "prima facie case" of negligence under

Puerto   Rico    Laws    title 31,   Section 5141,   the    plaintiffs   must

           2Because the District Court, at the plaintiffs' request,
dismissed all claims against all defendants except for Dr. Toledo
and the Hospital, those two parties were the only defendants that
remained at the time that the District Court issued the order that
the plaintiffs appeal. We hereafter use the term "defendants" to
refer to only Dr. Toledo and the Hospital.

                                     - 5 -
establish: "(1) the duty owed (i.e., the minimum standard of

professional     knowledge    and   skill   required    in    the   relevant

circumstances), (2) an act or omission transgressing that duty,

and (3) a sufficient causal nexus between the breach and the

claimed harm."    Cortés-Irizarry v. Corporación Insular De Seguros,

111 F.3d 184, 189 (1st Cir. 1997).          With respect to a negligence

claim that alleges medical malpractice, "Puerto Rico holds health

care professionals to a national standard of care."             Id. at 190.

In addition, for such claims, "Puerto Rico law presumes that

physicians exercise" the reasonable level of care.                  Id.   The

plaintiffs    "bear[]   the   burden   of   refuting   this   presumption."

Rolon-Alvarado v. Municipality of San Juan, 1 F.3d 74, 78 (1st

Cir. 1993).    Thus, " a plaintiff bent on establishing a breach of

a physician's duty of care ordinarily must adduce expert testimony

to limn the minimum acceptable standard and confirm the defendant

doctor's failure to meet it."       Cortés-Irizarry, 111 F.3d at 190.

          Against this legal backdrop, the plaintiffs proposed to

introduce at trial the testimony of "an expert in neurology,"

Dr. Allan Hausknecht ("Dr. Hausknecht"), to support their claim

that there had been a breach of the applicable standard of care

during López's surgery.       In addition, the plaintiffs "reserve[d]

the right to use as their own any expert witness announced by

defendants" in support of their negligence claims.            The defendants

proposed in response to introduce the testimony of their own expert

                                    - 6 -
witness: Dr. Ricardo H. Brau Ramírez ("Dr. Brau"), an "expert in

neurosurgery."

          Federal Rule of Evidence 702 provides:

          A witness who is qualified as an expert by
          knowledge, skill, experience, training, or
          education may testify in the form of an
          opinion or otherwise 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 addition, Federal Rule of Civil Procedure 26

requires that a party seeking to admit expert witness testimony

must submit "a written report" that "must contain:"

          (i) a complete statement of all opinions the
          witness will express and the basis and reasons
          for them;
          (ii) the facts or data considered by the
          witness in forming them;
          (iii) any exhibits that will be used to
          summarize or support them;
          (iv) the witness's qualifications, including
          a list of all publications authored in the
          previous 10 years;
          (v) a list of all other cases in which, during
          the previous 4 years, the witness testified as
          an expert at trial or by deposition; and
          (vi) a statement of the compensation to be
          paid for the study and testimony in the case.

Fed. R. Civ. P. 26(a)(2)(B).

                               - 7 -
             The parties stated in a joint pretrial conference report

filed on July 12, 2018, that each side would produce an expert

report     describing    its      respective   expert's    analysis.       The

plaintiffs produced two reports from Dr. Hausknecht that purported

to describe his expert opinion and the basis for it.

              The first of those reports set forth Dr. Hausknecht's

analysis of the surgery that had been performed on López by

Dr. Toledo.        The report explained that it was Dr. Hausknecht's

opinion both that Dr. Toledo had failed to properly "isolate" and

"protect" López's nerves and blood vessels during the surgery and

that this failure caused her injuries.               The second of those

reports, which was dated approximately one month after the first,

detailed     the   results   of    Dr.   Hausknecht's   own    "comprehensive

neurological examination" of López, as well as her medical history

and post-surgical symptoms.

             The defendants produced their own expert report from

their proposed expert, Dr. Brau.          Dr. Brau's report explained that

it was his expert opinion that Dr. Toledo followed the applicable

standard of care despite the unfortunate surgical outcome.

             A little over a year later, Dr. Toledo filed a motion

under Federal Rule of Evidence 702 and Federal Rule of Civil

Procedure 26(a)(2)(B) to "strike Dr. Hausknecht as an expert, or

at   least    his     opinion     that   Dr.   Toledo     committed    medical

malpractice."       The Hospital joined that motion.          Attached to the

                                      - 8 -
motion as exhibits were both of Dr. Hausknecht's expert reports

and a full transcript of Dr. Hausknecht's deposition testimony.

               The    motion    contended,       among      other     things,      that

Dr. Hausknecht's opinion in the report assumed negligence based

only on the negative outcome of the surgery and that his opinion

thereby relied on a "res ipsa loquit[ur]" theory of negligence.

As the District Court explained, that theory "is a torts doctrine

'providing that, in some circumstances, the mere fact of an

accident's      occurrence      raises    an   inference     of     negligence     that

establishes a prima facie case.'"              López Ramírez v. Grupo HIMA San

Pablo, Inc., No. 16-3192, 2020 WL 365554, at *5 n.2 (D.P.R. Jan.

22, 2020)(quoting Res Ipsa Loquitur, Black's Law Dictionary (11th

ed.    2019)).        The   motion   asserted      that   Puerto      Rico   law   has

foreclosed that theory of negligence in medical malpractice cases.

The motion thus contended that Dr. Hausknecht's testimony -- or,

at    least,    his   opinion    regarding       Toledo's    malpractice      --    was

inadmissible pursuant to Federal Rule of Evidence 702.

               The motion separately identified two additional reasons

to strike Dr. Hausknecht's "report and expected testimony," "or at

least his opinion that Dr. Toledo committed medical malpractice."

The motion argued first that Dr. Hausknecht's report did not

include the statement of his compensation required by Federal Rule

of Civil Procedure 26(a)(2)(B).                The motion also argued that he

                                         - 9 -
was not qualified to serve as an expert pursuant to Federal Rule

of Evidence 702 because he was "a neurologist, not a neurosurgeon."

            Approximately      two   months   later,      following   a   final

pretrial conference, the District Court stated in a minute entry

that it entered on the docket that it was "incline[d] to hear the

testimony of [Dr. Hausknecht] out of the presence of the Jury

pursuant to [Federal Rule of Evidence] 104."3              But, the District

Court, without first having held such a hearing, then later issued

an opinion and order striking "[Dr.] Hausknecht's proffered expert

opinions regarding the standard of care and Dr. Toledo's alleged

negligence."      López Ramírez, 2020 WL 365554, at *6.

            The District Court explained in its opinion that it was

rejecting       the   defendants'    contentions   that    Dr.   Hausknecht's

opinions must be struck under Federal Rule of Civil Procedure 26

because Dr. Hausknecht failed to include in his expert report a

statement of his compensation and under Federal Rule of Evidence

702 because he was not qualified as an expert.               Id. at *5.     The

District    Court      nonetheless    determined   that     Dr. Hausknecht's

proffered expert opinions concerning, respectively, the applicable

standard of care and Dr. Toledo's "deviation from" it must be

struck pursuant to Federal Rule of Evidence 702. Id. at *6.                The

            Federal Rule of Evidence 104 provides, "The court must
            3

decide any preliminary question about whether a witness is
qualified . . . . In so deciding, the court is not bound by
evidence rules, except those on privilege." Fed. R. Evid. 104(a).

                                     - 10 -
District Court also ruled that Dr. Hausknecht's deposition did not

salvage either of those opinions for purposes of Rule 702, because

the   deposition       was      "equally       unhelpful,    reiterating       that

Mrs. López's results 'can only be explained by improper procedure'

despite listing other causes for similar injuries."                   Id.

            That same day, the District Court issued an order for

Dr. Toledo "to file a motion for summary judgment" within three

weeks.   Dr. Toledo thereafter filed the motion, which the Hospital

joined. The plaintiffs contended in response that they could prove

their case even without Dr. Hausknecht's testimony as to his

proffered expert opinions, because they could rely on the testimony

of the defendants' expert, Dr. Brau.               "In the alternative," the

plaintiffs requested that the District Court reconsider its prior

ruling striking Dr. Hausknecht's testimony and, "in the best

interest    of     procedural    and    substantive       justice,"    allow       Dr.

Hausknecht to testify to the opinions regarding the applicable

standard of care and Dr. Toledo's alleged negligence.

            The District Court denied the plaintiffs' request for

reconsideration, granted Dr. Toledo's motion for summary judgment,

dismissed    the    plaintiffs'       claims    with    prejudice,    and   entered

judgment    in     favor   of   all    remaining       defendants.      See    López

Ramírez v.    Grupo    HIMA     San    Pablo,    Inc., No. 16-3192,         2020    WL

                                       - 11 -
5351851, at *1, *6, *8 (D.P.R. Sept. 4, 2020).                The plaintiffs

then filed this timely appeal of that summary judgment order.4

                                    II.

           We    first   address   the    plaintiffs'   challenges     to    the

District Court Order striking Dr. Hausknecht's proffered opinions

under Federal Rule of Evidence 702.          Because we find no merit to

those challenges, we then address the plaintiffs' separate grounds

for challenging the District Court's grant of summary judgment in

favor of the defendants.5

                                     A.

           As the Supreme Court of the United States explained in

Daubert v. Merrell Dow Pharmaceuticals, Inc., Federal Rule of

Evidence   702   assigns   a   "gatekeeping     role    for   the   judge"   to

"ensur[e] that an expert's testimony both rests on a reliable

           4The plaintiffs' appeal from the District Court's entry
of summary judgment against them permits us to consider their
challenge to the District Court's predicate order striking Dr.
Hausknecht's opinions. See Martínez-Serrano v. Quality Health
Servs. of P.R., Inc., 568 F.3d 278, 283 (1st Cir. 2009) (explaining
that when an appellant "designate[s] the final judgment in a case
as the appeal's object . . . such a notice of appeal is deemed to
encompass not only the final judgment but also all interlocutory
orders that merge into it").
          5 The plaintiffs also appear to assert that the District

Court imposed "too severe of a sanction" by excluding Dr.
Hausknecht's opinions.     But, even assuming that challenge is
sufficiently developed for us to consider, it has no merit, because
the District Court excluded Dr. Hausknecht's opinions pursuant to
Federal Rule of Evidence 702 and not as a sanction for the
plaintiffs' failure to comply with Federal Rule of Civil
Procedure 26.

                                   - 12 -
foundation and is relevant to the task at hand."                     509 U.S. 579,

597 (1993).         "The focus, of course, must be solely on principles

and methodology, not on the conclusions that they generate."                     Id.

at 595.      "So long as an expert's scientific testimony rests upon

'"good grounds," based on what is known,' it should be tested by

the adversarial process, rather than excluded for fear that jurors

will   not     be     able    to    handle   the   scientific        complexities."

Milward v. Acuity Specialty Prods. Grp., Inc. (Milward I), 639

F.3d 11, 15 (1st Cir. 2011) (internal citation omitted) (quoting

and citing Daubert, 509 U.S. at 590, 596).

             "There      is    an    important     difference        between    what

is unreliable support          and   what    a   trier   of   fact    may   conclude

is insufficient support for an expert's conclusion."                    Id. at 22.

Thus, "[w]hen the factual underpinning of an expert's opinion is

weak, it is a matter affecting the weight and credibility of the

testimony -- a question to be resolved by the jury."                   Id. (quoting

United States v. Vargas, 471 F.3d 255, 264 (1st Cir. 2006)).

             Nonetheless, "nothing in either Daubert or the Federal

Rules of Evidence requires a district court to admit opinion

evidence that is connected to existing data only by the ipse

dixit of the expert.           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).

So long, that is, as that gap is not "of the district court's

                                       - 13 -
making."   Milward I, 639 F.3d at 22 (quoting Kennedy v. Collagen

Corp., 161 F.3d 1226, 1230 (9th Cir. 1998)).

           "The party seeking to introduce the evidence has the

burden of establishing both its reliability and its relevance."

Milward v. Rust-Oleum Corp. (Milward II), 820 F.3d 469, 473 (1st

Cir. 2016) (citing Daubert, 509 U.S. at 593 n.10).    "We review the

district court's decision to admit or exclude expert testimony for

abuse of discretion," reviewing "[p]redicate factual findings" for

"clear error" and "pure questions of law . . . de novo."            Id.

at 472; see also Joiner, 522 U.S. at 146.

           The District Court struck the proffered opinions of

Dr. Hausknecht on two independent grounds under Federal Rule of

Evidence 702.   See López Ramírez, 2020 WL 365554, at *6.       First,

the District Court ruled that the plaintiffs failed to meet their

burden to show that Dr. Hausknecht had provided sufficient support

for the standard of care that he identified as being applicable to

the surgery in question. Id. Second, the District Court concluded

that the plaintiffs failed to meet their burden to show that Dr.

Hausknecht supportably had explained the basis for his opinion

that Dr. Toledo had deviated from the applicable standard of care,

insofar as Dr. Hausknecht had identified one.       Id.     As we will

explain, the District Court did not abuse its discretion in ruling

that the plaintiffs failed to meet their burden to show that

Dr. Hausknecht's   opinion   that   Dr. Toledo   deviated    from   the

                               - 14 -
applicable standard of care during the surgery rested on more than

res ipsa loquitur, which is a theory of negligence that the parties

in this case agree is not one that the plaintiffs may rely upon

under Puerto Rico law.       We thus need not address the District

Court's other ground for striking Dr. Hausknecht's testimony.        Id.

            Dr. Hausknecht stated in his expert report that the

applicable standard of care required a neurosurgeon performing the

type of surgery at issue to "identify, isolate, and protect" the

nerves and blood vessels in the brain.        But, the District Court

concluded, Dr. Hausknecht failed to "specify[] . . . why" the

"standard of care applicable to Mrs. López's case" was "not met."

Id.

            The   District   Court   noted   in   so   concluding   that

Dr. Hausknecht in his report "acknowledg[ed] the 'textbook' nature

of the operative report," which was a written summary of the

operation that Dr. Toledo signed, and the "inherent risks of the

surgery."   Id.   Indeed, according to both experts' summary of that

operative report, Dr. Toledo found during the surgery that there

were multiple perforators -- or small arteries that supply blood

to the brain -- coming out of a larger artery, the Anterior

Inferior Cerebellar Artery (AICA), and that the facial nerve had

been irritated.     Moreover, according to both experts' summary of

the operative report, Dr. Toledo, after finding as much, decided

                                - 15 -
not to decompress any contact points between the nerve and AICA,

to withdraw from the area, and to conclude the surgery.

           The   District    Court     then   went   on    to    explain   that,

notwithstanding Dr. Hausknecht's description of the operative

report as "'textbook,'" Dr. Hausknecht did not "provide any data

to sustain or explain the conclusory finding that there was a

deviation from the standard of care."          Id.   Moreover, the District

Court determined that "[a]lthough Dr. Hausknecht's report state[d]

that he included copies of journal articles that" he stated "'may

be helpful,' he fail[ed] to name them or relate the content of

said publications to his assertion that Dr. Toledo was negligent."

Id.   For these reasons, the District Court concluded that there

was "'simply too great an analytical gap' between the content of

the report and the opinion proffered."            Id. (quoting Joiner, 522

U.S. at 146).

           The    plaintiffs    do    not     identify     any   statement   in

Dr. Hausknecht's    report     that   undermines     the    District   Court's

assessment.      Dr. Hausknecht's report states that "[o]bviously,

damage to the[] perforators did occur secondary to some activity

during the surgery."     But, the plaintiffs do not identify -- and

we do not see -- where in the report Dr. Hausknecht explains the

basis for concluding that there was a deviation from the standard

of care.      There is instead only the conclusory statement that

                                     - 16 -
"[t]hese structures were not properly identified, isolated and

protected."

            For example, Dr. Hausknecht's report does not state that

Dr. Toledo touched a nerve or vessel that she should not have

touched, given the applicable standard of care.                       His report also

does not address whether or how Dr. Toledo could have avoided

manipulating any nerves or vessels.                     Nor does Dr. Hausknecht's

report reject the possibility, as Dr. Brau states in his competing

report, that this is a procedure in which "manipulation of the

blood vessels" cannot be avoided because "[t]his operation is

designed to mobilize blood vessels away from the facial nerve."

In   sum,   Dr. Hausknecht's          report     sets    forth    his    opinion      that

Dr. Toledo       was     not    sufficiently          careful     with      respect    to

"structures"      without       specifying       in     what     respect     Dr. Toledo

manipulated a "structure" in a manner that deviated from the

standard of care that he had identified.

            As     the     plaintiffs       point        out,     Federal     Rule      of

Evidence 702 "has been interpreted liberally in favor of the

admission of expert testimony."                Levin v. Dalva Bros., Inc., 459

F.3d 68, 78 (1st Cir. 2006).                   But, the plaintiffs have not

identified    anything         more   in   the    record       than   the    conclusory

statements Dr. Hausknecht made in his report that opined that

Dr. Toledo deviated from the standard of care -- statements that

                                        - 17 -
do not attempt to describe the principles or methods by which he

reached that opinion.

          Moreover, the plaintiffs do not develop any contention

that Dr. Hausknecht's deposition testimony -- which, we note, the

District Court also considered but found "equally unhelpful,"

López Ramírez, 2020 WL 365554, at *6 -- bridges the "analytical

gap" that the District Court identified between Dr. Hausknecht's

stated opinion in his report that there had been a deviation from

the standard of care and the basis for that opinion.   Id. (quoting

Joiner, 552 U.S. at 146).     On appeal, the plaintiffs refer to

Dr. Hausknecht's deposition only to show that he was qualified to

speak to the standard of care itself.   But, the District Court did

not dispute that he was qualified to do so.6    See López Ramírez,

2020 WL 365554, at *5.

          6  The plaintiffs did, after oral argument, submit a
letter pursuant to Federal Rule of Appellate Procedure 28(j) to
which they attached the publications that they contended
Dr. Hausknecht relied on when he stated in his report that various
articles he did not name "may be helpful in understanding [his]
final opinions and conclusions." The plaintiffs also included a
list of the titles and authors of these publications in their brief
to us on appeal. But, it remains the case that Dr. Hausknecht's
reference in his report to the unnamed articles does not mention
how those articles address the "analytical gap" between his
conclusion and the explanation for it that formed the basis for
the District Court's exclusion of his expert opinion.         López
Ramírez, 2020 WL 365554, at *6 (quoting Joiner, 522 U.S. at 146).
The plaintiffs' brief to us on appeal and the post-argument letter
purporting to attach those unnamed articles do not do so either.
Nor did the plaintiffs attempt to do so in their brief in
opposition   to   Dr. Toledo's   motion   in  limine   to   exclude
Dr. Hausknecht's testimony.

                              - 18 -
           The plaintiffs do emphasize that Puerto Rico law permits

a party seeking to prove negligence in a medical malpractice case

to   demonstrate   disputed    facts    "by   indirect   or   circumstantial

evidence."    But, the plaintiffs fail to show how Dr. Hausknecht's

report provides any circumstantial or inferential basis for his

opinion that Dr. Toledo's actions manipulated "structures" in a

manner that deviated from the standard of care.

           In sum, after reviewing the expert reports and the

arguments made to us regarding the record in this case and the

relevant law, we see no abuse of discretion in the District Court's

order excluding Dr. Hausknecht's expert opinion that Dr. Toledo

deviated from the applicable standard of care in performing the

surgery on López that is the predicate for her suit.             See United

States v. Zannino, 895 F.2d 1, 17 (1st Cir. 1990).                Thus, the

plaintiffs' challenge to the grant of summary judgment fails

insofar as it depends on a challenge to the District Court's

exclusion of the relevant opinions proffered by Dr. Hausknecht

pursuant to Federal Rule of Evidence 702.

                                       B.

           We turn, then, to the plaintiffs' contention that, even

if the District Court did not err in striking Dr. Hausknecht's

expert opinion regarding the deviation from the standard of care,

the District Court erred in granting summary judgment to the

defendants.     "To   defeat   a   motion     for   summary   judgment,   the

                                   - 19 -
nonmoving party must demonstrate the existence of a trialworthy

issue as to some material fact," i.e., a fact that "potentially

could   affect     the   suit's   outcome."   Cortés-Irizarry,    111   F.3d

at 187; see also Borges ex rel. S.M.B.W. v. Serrano-Isern, 605

F.3d 1, 5 (1st Cir. 2010).             That requires that a plaintiff

"affirmatively point to specific facts" that do so.              Feliciano-

Muñoz v. Rebarber-Ocasio, 970 F.3d 53, 62 (1st Cir. 2020) (quoting

McCarthy v. Nw. Airlines, Inc., 56 F.3d 313, 315 (1st Cir. 1995)).

Our review is de novo.       Milward II, 820 F.3d at 472–73.7

                                      1.

            The plaintiffs rely for this contention in part on what

the expert report that the defendants themselves filed in support

of their expert, Dr. Brau, showed.         The District Court determined,

however, that summary judgment was "proper even after reading Dr.

Brau's report in the light most favorable" to the plaintiffs.

López Ramírez, 2020 WL 5351851, at *7 (quotation marks and citation

omitted).       We see no basis for ruling otherwise.

            The District Court explained that, although "Dr. Brau's

report did not directly question or contradict Dr. Hausknecht's

standard of care . . . to identify, isolate, and protect nervous

            The plaintiffs in their briefing to us on appeal do
            7

not develop any independent argument as to why the District Court
erred in granting summary judgment to the Hospital in particular,
aside from citing to the general allegations contained in their
complaint.   They have therefore waived any such argument.    See
Zannino, 895 F.2d at 17.

                                    - 20 -
tissue," Dr. Brau's report set forth the conclusion that there was

"not even a trace of evidence in the medical chart that Dr. Toledo

failed to identify, isolate, and protect the nervous tissue and

vascular structure in this case."       Id. (emphasis and citations

omitted).   The District Court further explained that, because the

plaintiffs' claim that Dr. Brau may have left certain opinions out

of his report was "speculative at best," that conclusion did "not

create a factual dispute for purposes of summary judgment."     Id.

(emphasis and citation omitted).

            In response on appeal, the plaintiffs contend only that

"Dr. Brau's testimony and cross-examination[] will help the jury

to determine both the proper standards of care and the causal nexus

between Defendants' negligence and Plaintiffs' damages" and that

the District Court "erred" in rejecting that argument.      But, we

are not persuaded.

            Dr. Brau states in the report that "Dr. Toledo followed

the standard of care" and "took all precautions" to "minimize the

risks"; that "[i]t is highly improbable that direct surgical trauma

to the nerves or the brainstem occurred during surgery"; and that

there "is not even a trace of evidence in the medical chart that

Dr. Toledo failed to identify, isolate, and protect the nervous

tissue and vascular structure in this case."      The plaintiffs do

not explain how or why Dr. Brau's testimony would, despite these

statements, lend support to their case.    Nor do they identify any

                               - 21 -
statements in Dr. Brau's report that might support a finding that

there   remains   a     material   dispute    as   to   whether   there   was   a

deviation from the standard of care.                See Tropiagas de P.R.,

Inc. v. Certain Underwriters at Lloyd's of London, 637 F.3d 53, 56

(1st Cir. 2011).

           Indeed, Dr. Brau's report describes specific surgical

decisions that Dr. Toledo made that are consistent with Dr. Brau's

opinion that Dr. Toledo did not deviate from the standard of care.

For   example,    the    report    states   that   Dr. Toledo     "altered   the

dissection of the Facial Nerve" when "she was notified that some

electrical changes were recorded" and "stopped the mobilization

of" the blood vessel, the AICA, "when the nerve became irritated."

The report also states that "[n]o hemorrhage, rupture, or tear of

the perforators, AICA or the Vertebral Arteries occurred," and

that "[t]he estimated blood loss for the procedure" was "below the

average blood loss for this procedure."                 And, while Dr. Brau

reserved the right to "modify, alter,               amend, or change"        his

opinion, the plaintiffs have failed to point to any facts that

might demonstrate how Dr. Brau's testimony might change, let alone

whether such a change would support their case.

                                       2.

           The plaintiffs' final ground for challenging the grant

of summary judgment in favor of the defendants relies on an

exception to the general rule "that in a medical malpractice case

                                     - 22 -
under Puerto Rico law 'a factfinder normally cannot find causation

without the assistance of expert testimony.'"             Martínez-Serrano v.

Quality Health Servs. of P.R., Inc., 568 F.3d 278, 286 (1st Cir.

2009) (quoting Rojas–Ithier v. Sociedad Española de Auxilio Mutuo

y Beneficiencia, 394 F.3d 40, 43 (1st Cir. 2005)).              That general

rule rests on the understanding that "medical malpractice is a

field in which the issues tend to be scientifically driven and

more nuanced than in most tort cases," id., and that "Puerto Rico

law presumes that physicians exercise reasonable care."               Cortés-

Irizarry, 111 F.3d at 190.

           As the plaintiffs point out, we have recognized that

some medical malpractice cases brought under Puerto Rico law may

involve alleged conduct "sufficiently blatant or patent" to permit

a negligence claim to survive summary judgment without an expert

witness;   in   such   cases,   the   nature   of   the    alleged   error   in

treatment is such that "lay persons, relying on common knowledge

and experience, can legitimately recognize or infer negligence."

Rolon-Alvarado, 1 F.3d at 79. But, although the plaintiffs contend

that theirs is such a case, we cannot say that the District Court

erred in determining that the plaintiffs had not "proffer[ed]

evidence that Dr. Toledo's conduct was 'sufficiently blatant or

patent' that" a lay person "could infer that her negligence caused

Mrs. López's current state." López Ramírez, 2020 WL 5351851, at *8

(quoting Rolon-Alvarado, 1 F.3d at 79).

                                  - 23 -
            The plaintiffs do assert in arguing otherwise that even

Dr. Brau    "agrees   that   [López]'s    injuries    resulted    from     the

surgical manipulations performed by" Dr. Toledo and that a jury

could, on its own, determine that those manipulations were of the

avoidable and negligent kind. But, insofar as the plaintiffs mean

to argue that Dr. Brau's report sets forth an expert opinion that

Dr. Toledo performed the surgery negligently, it does not.

            Dr. Brau did state in the report that Dr. Toledo's

"[m]anipulation of [the] AICA or its perforator[] vessels could

have trigger[ed] [a] vasospasm," which could have created an

interruption in blood flow and "eventually evolv[ed] into an

infarction," or tissue death.      But, Dr. Brau also stated in that

same report that this "manipulation of the blood vessels" could

not "be avoided" because the "operation is designed to mobilize

blood vessels away from the facial nerve."           So, Dr. Brau's report

does not indicate that such manipulations were of the avoidable

kind that the plaintiffs, implicitly, contend that he agreed that

they were.

            Moreover, nothing in Dr. Brau's report provides support

for   the   plaintiffs'   assertion   that   Dr.     Toledo's    conduct   in

performing the surgery was so patently negligent that no expert

opinion to that effect is needed for their negligence claims to be

able to survive summary judgment.         And, finally, we see no basis

for concluding that a "lay" juror "relying on common knowledge and

                                 - 24 -
experience" can "infer," Rolon-Alvarado, 1 F.3d at 79, either that

the manipulations caused the injuries or, insofar as they did,

that they were the product of a deviation from the applicable

standard of care (even assuming that standard to be one that would

require   that    Dr. Toledo    "identify,     isolate,   and    protect    the

nervous tissue and vascular (circulation) in the affected area").

            Finally, insofar as the plaintiffs mean to rest their

contention that the exception recognized in Rolon-Alvarado should

apply on their allegation in their complaint "that Defendants were

'grossly negligent' because they did not provide Mrs. López with

adequate neurological evaluation and treatment during her surgery

and stay" at the hospital, and failed to provide the treatments

"'required to diagnose and/or avoid a massive stroke,'" they are

wrong to do so.      Without more, these "mere allegations are not

entitled to weight in the summary judgment calculus."                Borges, 605

F.3d at 3.

                                     III.

            The   judgment     of   the     District   Court    is    therefore

affirmed.

                                    - 25 -