                IN THE SUPREME COURT OF THE STATE OF IDAHO

                                       Docket No. 42158

ALESA TEREN EASTERLING, an              )
individual, through her parents, ALLEN  )
EASTERLING and TERESA EASTERLING, )
                                                              Boise, November 2015 Term
                                        )
    Plaintiff-Appellant,                )
                                                              2016 Opinion No. 6
                                        )
v.                                      )
                                                              Filed: January 25, 2016
                                        )
ERIC PAUL KENDALL, M.D.,                )
                                                              Stephen W. Kenyon, Clerk
                                        )
    Defendant-Appellant.                )
_______________________________________ )

       Appeal from the District Court of the Fourth Judicial District of the State of
       Idaho, Ada County. Hon. Cheri C. Copsey, District Judge.

       The judgment of the district court is affirmed in part and vacated in part.

       Racine, Olson, Nye, Budge & Bailey, Chartered, Pocatello, for appellant. Richard
       A. Hearn argued.

       Powers Tolman Farley, PLLC, Twin Falls, for respondent. Nicole L. Cannon
       argued.

                                    _____________________

J. JONES, Chief Justice
       Appellant, Alesa Easterling, brought this medical malpractice suit against Respondent,
Eric Kendall, M.D., alleging that Kendall was negligent in failing to diagnose her with a carotid
artery dissection, and that such misdiagnosis delayed her treatment and resulted in her suffering
permanent neurological damage. At trial, the district court granted Kendall’s motion for a
directed verdict. The district court concluded that Easterling failed to prove a medical
malpractice claim because she failed to present expert testimony to show that Kendall’s
misdiagnosis was the proximate cause of her injuries. Easterling appeals, contending that expert
testimony is not required under Idaho law to prove proximate cause in a medical malpractice
action. Additionally, Easterling appeals the district court’s orders excluding opinion testimony
from Easterling’s retained expert and treating physicians on the issue of causation and denying


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her motion to present rebuttal opinion testimony on causation in her case in chief. Easterling also
appeals the district court’s award of discretionary costs to Kendall. Kendall requests attorney
fees on appeal.
                                      I.
                       FACTUAL AND PROCEDURAL BACKGROUND
       On September 5, 2011, Alesa Easterling, then fifteen years old, was swimming at the
YMCA in Twin Falls, Idaho, when she fell from a large floating structure. After falling,
Easterling experienced a severe headache, vomiting, and numbness in her left arm. An
ambulance was called to the scene. When paramedics arrived, they noted that Easterling was
alert but was experiencing an obvious left facial droop and slurred speech. Due to concern that
Easterling may have suffered a stroke, she was air lifted to St. Luke’s Regional Medical Center
in Boise, Idaho.
       Upon arriving at St. Luke’s, Easterling was examined by emergency room physician Dr.
Kendall. When performing a neurological exam on Easterling, Kendall found that she exhibited a
subtle left side facial asymmetry which appeared to wax and wane. The triage nurse noted that
Easterling had trouble taking Tylenol and was dribbling out of the left side of her mouth. Kendall
noted in his report that Easterling hit her head when she fell from the floating structure. Whether
Kendall had a basis to include that finding in his report was a contested issue at trial. Kendall
ordered a CT scan and basic testing of Easterling, which did not reveal any abnormalities.
Kendall did not order an MRI scan or additional image testing. Believing that Easterling was
suffering from a concussion, Kendall consulted the on-call neurologist, who agreed with his
diagnosis. Kendall then prescribed anti-nausea medication for Easterling and discharged her
from St. Luke’s.
       The next morning, Easterling was taken to the emergency room in Twin Falls because
she was experiencing a severe headache and nausea and her father had observed her twitching in
her sleep. A CT Scan and MRI were performed. After reviewing the MRI, a radiologist
concluded that Easterling had a dissection of the right internal carotid artery. A carotid artery
dissection is a tear in an artery wall which causes bleeding. To prevent bleeding, the dissection
may clot. These blood clots then may break off and lodge in the brain, closing off blood flow and
causing stroke or stroke-like symptoms. The attending physician concluded that the dissection
had caused Easterling to have a stroke sometime in the previous six hours. Easterling was again
air lifted to St. Luke’s in Boise. Treating physicians at St. Luke’s in Boise agreed that Easterling


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had suffered a stroke due to a carotid artery dissection and Easterling was admitted for care in
the pediatric intensive care unit.
       Easterling remained in intensive care from September 6 to September 8, 2011. Treating
physicians struggled to determine the correct course of treatment for Easterling, including
whether anticoagulant treatment would be appropriate. Anticoagulants thin blood and can help
prevent blood clotting that may occur due to a dissection. However, anticoagulants also carry a
risk of causing hemorrhage, which could potentially be more damaging than a stroke caused by a
lack of blood supply. When admitted to the intensive care unit on September 6, Easterling was
started on anticoagulant treatment. However, on September 8, Easterling experienced another
stroke. Easterling’s treating physicians then consulted with several specialists about whether to
continue Easterling on anticoagulant treatment. Little study had been performed on the impact of
anticoagulant treatment in pediatric stroke patients, and the specialists consulted about
Easterling’s treatment disagreed about whether the potential benefits of anticoagulant treatment
outweighed the risk of hemorrhage. After an initial consultation with specialists on
September 8, Easterling was taken off anticoagulant treatment. However, after further
consultation later that day, Easterling was put back on a low dose anticoagulant and was
transferred to the University of Utah hospital. A few days after being transferred to the
University of Utah, there was concern that Easterling had suffered a hemorrhagic transformation
of her stroke and she was again taken off anticoagulant treatment. Easterling remained at
University of Utah until she was discharged on October 1, 2011. Easterling alleges that she has
suffered permanent neurological damage due to the series of strokes.
       On April 3, 2013, Easterling, through her parents, brought suit against Dr. Kendall, her
treating physician on September 5, 2011, for medical malpractice. Easterling alleged that
Kendall was negligent in misdiagnosing her with a concussion and that such misdiagnosis
resulted in her suffering further stroke and permanent neurological damage. The parties
stipulated to a pretrial discovery plan, whereby Easterling’s expert disclosures were due October
11, 2013, Kendall’s expert disclosures were due December 10, 2013, and Easterling’s rebuttal
expert disclosures were due January 9, 2014.
       On October 11, 2013, Easterling produced expert disclosures, disclosing Bruce Wapen,
M.D., FACEP, an emergency physician, as an expert on the appropriate standard of care and on
Kendall’s breach thereof. That same day, Easterling also produced a disclosure of non-retained



                                               3
experts which listed thirty-seven treating physicians who may be called to offer opinions
consistent with the medical records. Additionally, Easterling’s disclosure stated that five of
Easterling’s treating physicians may be called to testify that Dr. Kendall’s failure to diagnose
was a substantial factor in causing Easterling’s injuries. Kendall filed an objection to Easterling’s
disclosure of non-retained experts, arguing that Easterling’s disclosure of the treating physicians’
causation opinions did not provide a sufficient response to an interrogatory propounded by
Kendall in April 2013. Interrogatory No. 3 requested that Easterling disclose the identity of each
expert expected to testify and provide a complete statement of each expert’s opinions, the facts
relied on in forming those opinions, and any exhibits that would be used to support those
opinions.1
         On December 5, 2013, Easterling served supplemental answers to Interrogatory No. 3.
The December 5 supplementation stated that the five treating physicians identified in her
disclosure of non-retained experts would offer opinions on causation consistent with opinions
and facts expressed in their depositions and provided a list of quotes taken directly from each
treating physician’s deposition. Additionally, the December 5 supplementation stated that
Wapen, Easterling’s standard of care expert, would also offer opinion testimony on the issue of
causation. Wapen had been deposed on November 21, 2013. During his deposition, Wapen
informed Kendall’s counsel that Easterling’s counsel had asked him to offer opinions on
causation at trial. The December 5 supplementation quoted directly from Wapen’s deposition,
which stated that Wapen would testify that Kendall should have diagnosed Easterling with a
carotid artery dissection and started Easterling on anticoagulant treatment on September 5th and
the failure to do so was a substantial factor in causing her further stroke.
         In December 2013, the district court heard oral argument on Kendall’s objection to
Easterling’s disclosure of non-retained experts and issued an order denying Kendall’s motion to


1
  Kendall’s Interrogatory No. 3 requested the following information:
INTERROGATORY NO. 3: State the name and address of each person whom the plaintiffs expect to call
as an expert witness at the trial. For each such person:
         (a) State the subject matter on which the expert is expected to testify;
         (b) A complete statement of all opinions to be expressed and the basis and reasons therefore;
         (c) The facts, data or other information considered by the witness in forming the opinions;
         (d) Any exhibits to be used by the expert witness as a summary of or support for the opinions; and
         (e) Any qualifications of the witness, including a list of all publications authored by the witness
         within the preceding ten (10) years, the compensation to be paid for the testimony, and a list of
         any other cases in which the witness has testified as an expert at trial or by deposition within the
         four (4) preceding years.


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exclude the testimony. The district court found that Easterling had failed to properly disclose any
expert causation opinion held by non-retained experts in response to Interrogatory No. 3 in both
Easterling’s initial and supplemental disclosures. However, rather than exclude the testimony,
the district court gave Easterling an opportunity to properly supplement her discovery response
by January 10, 2014, and gave Kendall leave to renew the objection and seek costs if the
responses were inadequate.
       On January 8, 2014, Easterling supplemented her expert disclosures and responses for
Interrogatory No. 3 for both retained and non-retained experts. Easterling disclosed that Wapen
would testify that had Kendall not misdiagnosed her on September 5, she would have received
treatment for a carotid artery dissection on that date, when the benefits of treatment would be at
their maximum. Wapen’s opinions were stated to be based on the depositions of treating
physicians and Easterling’s medical records, which were summarized in the disclosure, and 200
pages of attached scholarly articles.
       Additionally, the January 8 supplementation stated that the five treating physicians would
opine at trial that Kendall’s misdiagnosis of Easterling caused her not to receive treatment for a
carotid artery dissection on September 5 and if treatment had been timely provided, it would
have more likely benefited her. The disclosures for each treating physician were essentially
identical and included an identical summary of quotes from the medical record and depositions
of treating physicians which allegedly formed the basis of each expert’s opinion—the same
summary provided to support the opinion of retained expert Wapen. On the same day, Easterling
filed her rebuttal expert disclosures, disclosing both Wapen and Dr. J. Fritz Shumtz as retained
experts to offer rebuttal testimony on the issue of causation.
       On January 24, 2014, Kendall filed a motion to strike Wapen’s causation options.
Kendall argued that the district court should strike Wapen’s causation opinions because
Easterling had not disclosed that Wapen would testify as to causation until a month after
Easterling’s initial disclosures were due and the supplementations of Wapen’s opinions on
December 5th and January 8th were not sufficient. The same day, Kendall filed a renewed
objection to Easterling’s disclosure of non-retained experts, arguing that the January 8
supplementation failed to properly disclose any expert causation opinion held by the treating
physicians because none of the treating physicians identified by Easterling had provided, or
agreed to provide, opinion testimony on causation. The district court heard oral argument on



                                                 5
Kendall’s motions and issued an order excluding opinion testimony on causation from Wapen
and the treating physicians in Easterling’s case in chief. Although the court precluded Wapen
from testifying on causation in Easterling’s case in chief, the court reserved ruling on whether
Wapen could testify as a rebuttal causation expert.
       Trial began on March 10, 2014. On March 17, 2014, Easterling filed a motion seeking to
have retained experts Wapen and Shumtz offer rebuttal testimony on the issue of causation
during her case in chief. Easterling argued that Kendall had opened the door to rebuttal testimony
on the issue of causation by eliciting evidence regarding causation on cross examination of Dr.
Wapen and treating physicians Dauplaise and Jernigan. The district court denied Easterling’s
motion, concluding that causation had not been raised during cross examination and, therefore,
the door had not been opened to allow rebuttal testimony on that issue.
       At the close of Easterling’s case in chief, Kendall moved for a directed verdict. Kendall
contended that Easterling failed to provide substantial evidence to prove Kendall breached the
standard of care and that the breach was the proximate cause of Easterling’s injuries. As relevant
to this appeal, Kendall argued that Easterling failed to provide substantial evidence to prove
causation because she did not provide any expert opinion testimony on that issue at trial.
Easterling argued that proximate cause was reasonably inferable from the chain of circumstances
presented in this case and, therefore, expert causation testimony was not necessary. The district
court granted Kendall’s motion for a directed verdict, holding that Easterling failed to provide
substantial evidence to prove proximate cause. The district court reasoned that a jury is simply
not qualified to determine whether Dr. Kendall’s failure to properly diagnose and the potential
delay in treatment were a substantial cause of Easterling’s injuries without reliance on expert
testimony or evidence. Kendall filed a memorandum for costs and attorney fees. The district
court denied Kendall’s request for attorney fees, but awarded Kendall $25,994.93 in costs as a
matter of right and $49,463.94 in discretionary costs. Easterling timely appealed.
                                            II.
                                     ISSUES ON APPEAL
   1. Whether the district court abused its discretion by excluding Dr. Wapen’s opinion
      testimony on causation in Easterling’s case in chief.
   2. Whether the district court abused its discretion by excluding the treating physicians’
      opinion testimony on causation.
   3. Whether the district court abused its discretion by denying Easterling’s motion to present
      rebuttal causation testimony during her case in chief.


                                                6
   4. Whether the district court erred by granting Kendall’s motion for directed verdict.
   5. Whether the district court abused its discretion by awarding Kendall discretionary costs.
   6. Whether Kendall should be awarded attorney fees on appeal.
                                         III.
                                   STANDARD OF REVIEW
       This Court conducts “a review of the record to determine if the finding of the trial court
that there was a discovery violation is supported by substantial and competent evidence.” State v.
Stradley, 127 Idaho 203, 207–08, 889 P.2d 416, 420–21 (1995). The Court reviews the actual
sanction imposed under an abuse of discretion standard. Id. Likewise, the Court applies the abuse
of discretion standard to review both a district court’s decision whether to allow rebuttal
testimony and a district court’s award of discretionary costs. Hayden Lake Fire Prot. Dist. v.
Alcorn, 141 Idaho 307, 314, 109 P.3d 161, 168 (2005); Van Brunt v. Stoddard, 136 Idaho 681,
686, 39 P.3d 621, 626 (2001). “To determine whether a trial court has abused its discretion, this
Court considers whether the district court: (1) perceived the issue as one of discretion; (2) acted
within the outer boundaries of that discretion consistent with applicable legal standards; and (3)
reached its decision through the exercise of reason.” Hansen v. Roberts, 154 Idaho 469, 472, 299
P.3d 781, 784 (2013).
       “When reviewing a decision to grant or deny a motion for a directed verdict, this Court
applies the same standard the trial court applied when originally ruling on the motion.” April
Beguesse, Inc. v. Rammel, 156 Idaho 500, 508–09, 328 P.3d 480, 488–89 (2014) (citation and
internal quotation marks omitted). The Court determines
       whether there was sufficient evidence to justify submitting the claim to the jury,
       viewing as true all adverse evidence and drawing every legitimate inference in
       favor of the party opposing the motion for a directed verdict. This test does not
       require the evidence be uncontradicted, but only that it be of sufficient quantity
       and probative value that reasonable minds could conclude that a verdict in favor
       of the party against whom the motion is made is proper. Where a non-moving
       party produces sufficient evidence from which reasonable minds could find in its
       favor, a motion for directed verdict should be denied.
Id. at 509, 328 P.3d at 489.
                                              IV.
                                           ANALYSIS
       The ultimate issue on appeal is whether the district court erred in granting Kendall’s
motion for a directed verdict. To determine that issue, it is necessary to first address the district



                                                 7
court’s order excluding the testimony on causation that retained expert Wapen and the treating
physicians would have offered and the district court’s denial of Easterling’s motion to present
rebuttal causation testimony in her case in chief.
   1. The district court did not abuse its discretion by excluding Wapen’s opinion
      testimony on causation.
       In “determining whether the trial court abused its discretion in imposing a sanction for a
discovery violation, we must first determine whether a discovery violation occurred.” Stradley,
127 Idaho at 208, 899 P.2d at 421. For retained experts, a party is required to disclose
       a complete statement of all opinions to be expressed and the basis and reasons
       therefore; the data or other information considered by the witness in forming the
       opinions; any exhibits to be used as a summary of or support for the opinions; any
       qualifications of the witness, including a list of all publications authored by the
       witness within the preceding ten years; the compensation to be paid for the
       testimony; and a listing of any other cases in which the witness has testified as an
       expert at trial or by deposition within the preceding four years.
I.R.C.P. 26(b)(4)(A)(1)(i). The timing for such disclosures shall be set in the district court’s
scheduling order. I.R.C.P. 16(a)(2). A district court has authority to sanction parties for non-
compliance with scheduling orders, including prohibiting parties from introducing untimely
disclosed evidence. I.R.C.P. 16(i); I.R.C.P. 37(b)(2)(B).
       The district court ruled that Easterling failed to timely and sufficiently disclose Wapen as
an expert anticipated to testify as to causation and, therefore, precluded Wapen from offering
opinion testimony on causation in Easterling’s case in chief. Kendall’s motion to strike Wapen’s
causation testimony was based on Idaho Rules of Civil Procedure 16(i) and 26(e)(4). In its
written order, the district court did not expressly state which authority it relied on in excluding
Wapen’s testimony.
       The parties disagree as to whether the trial court excluded Wapen’s testimony under Rule
16(i) as a sanction for violating the court’s scheduling order or as a sanction for failing to
seasonably and adequately supplement the expert disclosure as required by Rule 26(e). While the
district court’s written order does not provide the basis for excluding Wapen’s causation
testimony, the court’s ruling at the oral hearing strongly suggests the district court’s ruling was
based on Rule 16(i). At the hearing, the district court expressed concern about Easterling’s
failure to disclose Wapen’s causation testimony by the initial disclosure deadline. The court
found that “[t]his isn’t a change of opinion … it is as though you went out and hired a new expert
…. That’s not a seasonable supplementation issue. It’s a new expert after the time for your expert


                                                 8
disclosure.” Here, the district court found that Easterling had violated the court’s scheduling
order by disclosing what was in essence a new expert witness after the deadline for Easterling’s
initial disclosures.
        The district court’s scheduling order required that the parties identify each expert and
provide the subject matter each witness is expected to testify to and all information required
under Rule 26(b)(4). Here, Easterling timely disclosed that Wapen would offer opinion
testimony as to the appropriate standard of care and Kendall’s breach thereof on October 11,
2013. However, there was no indication in the initial disclosure that Wapen would testify as to
causation. Kendall first learned that Wapen would offer opinion testimony on causation during
Wapen’s deposition on November 21, 2013, over a month after Easterling’s initial disclosures
were due. Two weeks later, Easterling served her December 5 supplementation, indicating that
Wapen would offer opinion testimony on the issue of causation. However, this supplementation
did not provide any of the information required to be disclosed for retained experts under Rule
26(b)(4). The supplementation merely stated that Wapen would testify consistent with his
deposition testimony and then provided direct quotes taken from Wapen’s deposition on
November 21. The supplementation did not state what Wapen’s opinions would be, the basis for
Wapen’s causation opinions, or any facts or data that Wapen relied on in developing those
opinions. Easterling did not even attempt to provide such information until her January 8
supplementation and rebuttal disclosures, three months after Easterling’s initial disclosures were
due and one month after Kendall’s initial disclosures were due.
        Easterling argues that the district court’s ruling is at odds with the Court’s ruling in
Edmunds v. Kraner, 142 Idaho 867, 136 P.3d 338 (2006). In Edmunds, the plaintiff had disclosed
his standard of care expert prior to the district court’s deadline, but had later filed an affidavit
changing the expert’s opinion on the local standard of care. Id. at 872, 136 P.3d at 343. The
district court excluded the affidavit, finding that the affidavit was untimely under the discovery
order and Rule 26(e) because it was filed more than a year after the pretrial order deadline and
contained different opinions from those expressed in the first disclosure. Id. at 873, 136 P.3d at
344. The Court held that the district court abused its discretion because the district court’s
decision to exclude the affidavit was based on a pretrial order that only asked for the names—not
opinions—of experts and Idaho law specifically contemplates that expert testimony can change
after the initial disclosure and can be seasonally supplemented. Id. at 874, 136 P.3d at 345.



                                                 9
Easterling argues that, under Edmunds, she did not violate Rule 16 or 26(e) because Wapen had
been disclosed as an expert by the initial disclosure deadline and the disclosure was seasonably
supplemented to include causation opinions in the December 5 and January 8 supplementations.
        However, this case differs from Edmunds. Here, the scheduling order required that
Easterling provide all the information required under Rule 26(b)(4) in her initial disclosures, not
just the name of each expert. Additionally, unlike Edmunds, no opinion expressed in Wapen’s
initial disclosure was modified. Rather, Easterling sought to have Wapen offer brand new
opinions on an entirely different subject matter from that in her initial disclosures. This is not a
case where the initial disclosures were “rejected modified, expanded upon or otherwise altered.”
Id. Easterling essentially disclosed a brand new expert and did not attempt to provide any of the
information required under the scheduling order and Rule 26(b)(4) until the January 8
supplementation—three months after her initial disclosures were due. The district court’s finding
that Easterling violated the scheduling order by not timely or sufficiently disclosing Wapen as an
expert on causation was supported by substantial and competent evidence. Rule 16(i) provides
that if a party violates a court’s scheduling order the court may sanction the party by excluding
evidence as provided in Rule 37(b)(2)(B). I.R.C.P. 16(i). Therefore, the district court did not
abuse its discretion by excluding Wapen’s opinion testimony on causation.
    2. The district court did not abuse its discretion by excluding the treating physicians’
       opinion testimony on causation.
        At the time the district court excluded the treating physicians’ opinion testimony on
causation, the parties did not have an affirmative duty to disclose the opinions of non-retained
experts under Idaho Rule of Civil Procedure 26(b)(4).2 However, the Idaho Court of Appeals had
held that parties do have a duty to respond to discovery requests concerning the facts and
opinions to which non-retained experts will testify. Clark v. Raty, 137 Idaho 343, 345, 48 P.3d
672, 674 (Ct. App. 2002). “[E]xpert testimony that is not subject to the discovery limitations of
Rule 26(b)(4) is not immune from discovery but, to the contrary, is subject to the full panoply of

2
  The district court’s order was issued in February 2014. In April 2014, Rule 26(b)(4) was amended to add
subsection (A)(1)(ii):
         For individuals with knowledge of relevant facts not acquired in preparation for trial and who have
         not been retained or specially employed to provide expert testimony in the case: a statement of the
         subject matter on which the witness is expected to present evidence under Idaho Rule of Evidence
         702,703 or 705, and a summary of the facts and opinions to which the witness is expected to
         testify.
I.R.C.P. 26(b)(4)(A)(1)(ii). This amendment became effective in July 2014.



                                                    10
discovery that is otherwise authorized by the civil rules.” Id. Parties have a duty to answer
interrogatories asking for the facts and opinions to which their non-retained experts will testify
and a duty to seasonably supplement their answers pursuant to Rule 26(e)(1)(B). Id. at 346, 48
P.3d at 675.
       Interrogatory No. 3 requested that Easterling disclose the identity of each expert expected
to testify and provide a complete statement of each expert’s opinions, the facts relied on in
forming those opinions, and any exhibits that would be used to support such opinions. On
October 11, 2013, Easterling initially disclosed that five treating physicians may be called to
testify that, to a reasonable degree of medical certainty, Dr. Kendall’s failure to diagnose was a
substantial factor in causing the injuries suffered by Easterling. Easterling’s December 5
supplementation merely provided that the treating physicians would provide testimony consistent
with their depositions and quoted excerpts directly from each physician’s deposition. As found
by the district court, neither of these disclosures provided the information requested in
Interrogatory No. 3 because Easterling did not provide the opinions of the treating physicians or
the factual basis for those opinions. Rather than exclude the causation testimony of the treating
physicians at that point, the district court acted within its discretion and gave Easterling one more
opportunity to supplement her response to Interrogatory No. 3.
       Although the January 8 supplementation was lengthy, it nonetheless failed to provide an
adequate response to Interrogatory No. 3. The disclosures for each of the five treating physicians
at issue were identical. Each disclosure provided that the treating physician was expected to
testify that Dr. Kendall’s misdiagnosis of Easterling caused her not to receive treatment for her
carotid artery dissection on September 5, 2011, and if treatment had been provided, it would
have more likely than not benefitted her. Each treating physician’s opinion was allegedly based
on his or her treatment of Easterling and information in her medical records. Each disclosure was
also accompanied by the same twenty-page summary of quotes taken from the medical records
and depositions—identical to the summary that accompanied Wapen’s supplemental disclosure.
       At the February 28 hearing on Kendall’s motion to strike, the district court was clearly
disconcerted when Easterling’s counsel disclosed that he had not actually consulted any of the
treating physicians when drafting the January 8 supplementation because the treating physicians
refused to speak with him. None of the opinions disclosed were actually provided by the treating
physicians, nor had any of the treating physicians indicated that they would offer causation



                                                 11
opinions at trial. What Easterling’s counsel actually provided in the January 8 supplementation
was counsel’s hope for what the treating physicians might say if he subpoenaed them and put
them on the stand. At oral argument, the district court ruled that the treating physicians could
testify about their treatment but Easterling could not attempt to elicit causation opinions. The
court reasoned that the experts could not give expert opinions about causation unless Easterling
had previously disclosed what their opinions would be so that Kendall could be adequately
prepared for trial.
        Easterling argues that she met the requirements of Rule 26 by providing opposing
counsel with what Easterling’s counsel expected the treating physicians would testify to at trial.
This argument appears to be based on language in the scheduling order requiring disclosure of
“the subject matter on which the [expert] witness is expected to testify.” One can say what a
witness’ expected testimony may be without actually having spoken with the witness. However,
the scheduling order requirement continues, “and information required by Rule 26(b)(4) of the
Idaho Rules of Civil Procedure.” Providing counsel’s mere expectation as to what an expert
opinion might be, without any reasonable basis to support that expectation, does not comport
with Rule 26 and the policies underlying expert witness discovery. “It is fundamental that
opportunity be had for full cross-examination, and this cannot be done properly in many cases
without resort to pretrial discovery, particularly when expert witnesses are involved.” Clark v.
Klein, 137 Idaho 154, 158, 45 P.3d 810, 814 (2002) (citation omitted). “Before an attorney can
even hope to deal on cross-examination with an unfavorable expert opinion he [or she] must
have some idea of the bases of that opinion and the data relied upon.” Id. Easterling failed to
provide Kendall with accurate information as to the treating physicians’ causation opinions and
whether the treating physicians even held any such opinions. Here, the district court’s finding
that Easterling violated Rule 26(e) by not properly supplementing her responses to Interrogatory
3 was supported by substantial and competent evidence. Rule 26(e) provides that the court may
exclude testimony not disclosed by a required supplementation. I.R.C.P. 26(e). Therefore, the
district court did not abuse its discretion in excluding such testimony at trial.
    3. The district court did not abuse its discretion by denying Easterling’s motion to
       include rebuttal causation testimony in her case in chief.
        Under Idaho Rule of Evidence 611, the trial court shall
        exercise reasonable control over the mode and order of interrogating witnesses
        and presenting evidence so as to (1) make the interrogation and presentation


                                                  12
       effective for the ascertainment of the truth, (2) avoid needless consumption of
       time, and (3) protect witnesses from harassment or undue embarrassment.
I.R.E. 611(a). “Exercise of this control is a question of the trial court's discretion.” State v. Koch,
157 Idaho 89, 101, 334 P.3d 280, 292 (2014). The issue in this case deals with rebuttal evidence.
“Rebuttal evidence is evidence that explains, repels, counteracts, or disproves evidence which
has been introduced by or on behalf of the adverse party.” Van Brunt v. Stoddard, 136 Idaho 681,
685–86, 39 P.3d 621, 625–26 (2001).
       Easterling moved the district court to allow her to present causation testimony from her
rebuttal experts in her case in chief, contending that, during cross-examination of retained expert
Wapen and treating physicians Dauplaise and Jernigan, Kendall opened the door to causation
testimony. The district court denied the motion, reasoning that Kendall had not questioned any of
the experts on causation issues and, therefore, rebuttal causation testimony would be
inappropriate. The court recognized that the matter was one of discretion. Additionally, the court
acted within the bounds of its discretion and reached its ruling through reason.
       Wapen testified during trial that, in his opinion, Kendall failed to accurately record
Easterling’s medical history and failed to perform additional imaging studies. Wapen then
opined that it was below the standard of care to fail to conduct those studies which would have
led to the proper diagnosis—a carotid artery dissection. On cross examination, Kendall’s counsel
questioned Wapen about whether the symptoms presented by Easterling on September 5, 2011,
could be indicative of other ailments besides a carotid artery dissection, about other conditions
that may cause stroke-like symptoms, and about tests that may be used in diagnosing a person
presenting stroke symptoms. Additionally, Kendall’s counsel asked Wapen if he had reviewed
records in which providers questioned whether a carotid artery dissection was the correct
diagnosis.
       Dr. Dauplaise testified on direct examination that he treated Easterling from September 6
to September 8, 2011, and, during the course of his treatment, he diagnosed Easterling with a
carotid artery dissection and started Easterling on anticoagulation therapy. Similarly, Dr.
Jernigan testified on direct examination that he was consulted by Dauplaise as to Easterling’s
diagnosis and the appropriate course of treatment. On cross examination, Kendall’s counsel
asked both treating physicians whether they had any doubt as to Easterling’s diagnosis and/or the
appropriate course of treatment.



                                                  13
       In ruling on Easterling’s motion, the district court found that Easterling had not shown
that the above questioning had opened the door to causation. The court found that the cross
examination of Wapen was generally limited to determining what Wapen had considered in
determining that the proper diagnosis was a carotid artery dissection and that Kendall’s counsel
had been very careful to avoid causation issues. The court then found that the cross examination
of the treating physicians did not open up the door to causation testimony.
       Easterling argues that the district court abused its discretion by not considering the
prejudice to Easterling in not allowing the rebuttal causation testimony in her case in chief.
Easterling relies on State v. Colon, a case from the Connecticut Supreme Court, which discussed
the exclusion of rebuttal testimony in a murder case where the defendant was sentenced to death.
272 Conn. 106, 186–87, 864 A.2d 666, 722 (2004). There, the Connecticut Supreme Court found
that a court, in its discretion, may allow rebuttal testimony that would ordinarily be inadmissible,
where the other party opened the door to rebuttal and not allowing such rebuttal would result in
prejudice. Id. However, the holding in Colon is largely irrelevant in this case, as the district court
specifically found that the door to rebuttal causation testimony had not been opened through
cross-examination.
       The district court’s determination that Kendall had not opened the door for rebuttal
causation testimony was reached through an exercise of reason and the district court acted within
its discretion in concluding that rebuttal testimony on that issue would, therefore, be
inappropriate.
   4. The district court did not err in granting Kendall’s motion for directed verdict.
       In a medical malpractice case, a “plaintiff has the burden of proving not only that a
defendant failed to use ordinary care, but also that the defendant’s failure to use ordinary care
was the proximate cause of damage to the plaintiff.” Pearson v. Parsons, 114 Idaho 334, 339,
757 P.2d 197, 202 (1988) (citation and internal quotation marks omitted). “To establish
proximate cause, a plaintiff must demonstrate that the provider’s negligence was both the actual
and legal (proximate) cause of his or her injury.” Coombs v. Curnow, 148 Idaho 129, 139, 219
P.3d 453, 463 (2009). Actual cause “is a factual question focusing on the antecedent factors
producing a particular consequence.” Id. at 139–40, 219 P.3d at 463–64. Legal cause exists when
“it is reasonably foreseeable that such harm would flow from the negligent conduct.” Id. at 140,
219 P.3d at 464 (citation and internal quotation marks omitted).



                                                 14
       “Proximate cause in medical malpractice cases involving more than one possible cause of
injury will be established if it is shown that the defendant’s conduct was a substantial factor in
bringing about the injury suffered by the plaintiff.” Id. (citation and internal quotation marks
omitted). Whether negligent conduct was a substantial factor in bringing about the plaintiff’s
injuries “may be proven by direct evidence or by showing a ‘chain of circumstances from which
the ultimate fact required to be established is reasonably and naturally inferable.’” Id. (quoting
Weeks v. E. Idaho Health Serv., 143 Idaho 834, 839, 153 P.3d 1180, 1185 (2007)). “The question
of proximate cause is one of fact and almost always for the jury.” Id. (internal quotation marks
omitted).
       Idaho Code sections 6-1012 and 6-1013 require that, in medical malpractice cases, the
applicable standard of care and breach of that standard be proved by expert testimony. Id. There
is no such provision requiring expert testimony to prove proximate cause. Rather, the admission
of testimony to prove proximate cause in medical malpractice cases is governed solely by the
Idaho Rules of Evidence. Sheridan v. St. Luke’s Reg’l Med. Ctr., 135 Idaho 775, 785, 25 P.3d 88,
98 (2001). Although expert testimony is not expressly required to establish causation in medical
malpractice cases, “such testimony is often necessary given the nature of the cases.” Coombs,
148 Idaho at 140, 219 P.3d at 464. “Expert testimony is generally required because ‘the causative
factors are not ordinarily within the knowledge or experience of laymen composing the jury.’”
Id. (quoting Flowerdew v. Warner, 90 Idaho 164, 170, 409 P.2d 110, 113 (1965)).
       At trial, Easterling presented evidence that on September 5, 2011, she exhibited signs of
stroke including left side paralysis, facial drooping, and slurred speech. Kendall testified that
when performing a neurological exam on Easterling he found that she exhibited a subtle left side
facial asymmetry which appeared to wax and wane. Kendall also testified that he had been
informed by the triage nurse that Easterling had trouble taking Tylenol and was dribbling out of
the left side of her mouth. These symptoms were noted in Kendall’s medical report. Kendall
ordered a CT scan and basic testing which did not reveal any abnormalities, but he did not order
an MRI or additional image testing.
       Wapen testified that a very common presentation for a dissection includes a headache on
the same side as the dissection, weakness or paralysis on the opposite side, and waxing and
waning facial asymmetry. Wapen opined that Kendall breached the local standard of care by
recording that Easterling hit her head when Kendall’s evaluation had not revealed any head



                                               15
injury and no other medical personnel that day had reported a head injury. Additionally, Wapen
testified that Kendall breached the standard of care by concluding that Easterling had no
neurological abnormalities after documenting signs of neurological abnormalities and by not
conducting additional imaging studies and an MRI which would have led Kendall to the proper
diagnosis—a carotid artery dissection.
       Evidence was presented showing that Easterling experienced a stroke within twenty-four
hours of being discharged by Kendall. Dr. Duplaise, one of Easterling’s treating physicians,
testified that he diagnosed Easterling on September 6, 2011, with a carotid artery dissection and
that he started Easterling on anticoagulant treatment. Testimony at trial showed that a carotid
artery dissection is a tear in an artery wall that can create a risk of blood clots forming and the
clots then may cut off blood flow to part of the brain and cause stroke or stroke-like symptoms.
Dr. Jernigan, another one of Easterling’s treating physicians, testified that on September 6 he
concluded that anticoagulant treatment would be appropriate in order to prevent a new blood clot
from forming or an existing clot from extending and causing further injury. It is undisputed in
the record that anticoagulant treatment does carry a risk of hemorrhage and Easterling
experienced further strokes after starting anticoagulant treatment.
       Easterling contends that the above evidence established a chain of circumstances from
which a reasonable person could conclude that Easterling’s injury was a natural consequence of
Kendall’s misdiagnosis and that his failure to diagnose the dissection was a proximate cause of
her injuries. Here, Easterling’s medical malpractice claim alleges that Kendall’s failure to
diagnose Easterling with a carotid artery dissection on September 5, 2011, delayed Easterling’s
treatment for the dissection until September 6, 2011. To avoid a directed verdict, Easterling
needed to present sufficient evidence that a reasonable jury could find that the one-day delay in
treatment resulting from Kendall’s misdiagnosis was a substantial factor in causing Easterling’s
injuries. The specific issue here is whether Easterling needed to present expert testimony to
support such a finding or whether the evidence on the record presented a chain of circumstances
from which proximate cause could be reasonably and naturally inferred by a jury.
       The district court found that expert testimony was necessary to prove proximate cause
because the proper treatment for a carotid artery dissection and the effect of delaying such
treatment are not within the ordinary experience of the average person. Easterling argues that the
district court improperly weighed conflicting evidence of whether anticoagulant treatment was



                                                16
appropriate in ruling on Kendall’s motion for a directed verdict. In ruling on Kendall’s motion,
the district court discussed the uncertainty among treating physicians and consulting experts on
whether anticoagulant treatment would be appropriate in Easterling’s case. After Easterling
experienced a stroke on September 8, while on anticoagulant treatment, treating physicians
consulted with several pediatric neurologists and radiologists, and there was no clear answer as
to whether anticoagulant treatment should be continued. For example, one radiologist opined that
the risk of bleeding associated with anticoagulant treatment may outweigh the benefits. A
pediatric neurologist stated that anticoagulant treatment would be appropriate because it is less
likely to cause bleeding in children, but acknowledged that not treating with anticoagulants may
also be appropriate.
       The district court reasoned that “where the treating physicians, all highly-trained medical
specialists like pediatric neurologists, testify that they were unsure of what treatment was
appropriate … the treatment and the effects of that treatment or the delay in that treatment simply
cannot be within the knowledge or experience of laymen.” The court then went through the
testimony of the treating physicians emphasizing how difficult Easterling’s diagnosis and
treatment had been and concluded that asking the jury to determine a disease mechanism, the
proper treatment and how a delay affected Easterling’s injuries, as well as the outcome of proper
treatment, is asking the jury to do nothing more than speculate. While the district court did
consider the uncertainty of treating physicians in ruling on Kendall’s motion, the court
specifically stated that it was considered for the sole purpose of demonstrating the complex
nature of the evidence and why a lay person cannot arrive at a decision as to causation without
the benefit of an expert. The district court did not improperly weigh conflicting evidence as to
whether anticoagulant treatment was the appropriate treatment for a dissection. Rather, the court
used the treating physicians’ uncertainty as an example of why lay persons would not be able to
determine what treatment would have been appropriate on September 5 or whether the delay in
treatment had an impact on Easterling’s injuries without the aid of expert testimony.
       Easterling relies on Sheridan, where this Court held that a district court did not err in
denying a defendant’s motion for a directed verdict even though the plaintiffs had not offered
expert testimony to prove proximate cause. 135 Idaho at 786, 25 P.3d at 99. In that case, the
plaintiffs had brought a claim against St. Luke’s and their physician for negligently treating their
son’s jaundice leading to permanent and irreparable brain damage. Id. at 778, 25 P.3d at 91. At



                                                17
trial, it was undisputed that the plaintiffs’ son had jaundice within 24 hours of his birth and
testimony established that the presence of jaundice within the first twenty-four hours of birth
requires further evaluation such as serum bilirubin measurement. Id. at 786, 25 P.3d at 99.
Evidence was also presented that “high bilirubin levels can be successfully treated by the use of
bili lights and blood exchange transfusions.” Id. The plaintiffs presented testimony that the
treating nurses at St. Luke’s had breached the standard of care by not charting the progression of
jaundice, not noting possible blood incompatibility problems between the mother and child, and
by sending the plaintiffs home without warning them that the newborn’s jaundice was abnormal.
Id. Three days later, the newborn was re-hospitalized and diagnosed with kernicterus, “a form of
cerebral palsy associated with neonatal history of elevated bilirubin, a symptom of which is
jaundice.” Id. This Court found that, although “it was days later before the high bilirubin levels
were measured, a jury could reasonably and naturally infer from the chain of circumstances that
a breach of the standard of care in the first hospital stay proximately caused [the child’s]
injuries.” Id.
        However, in Swallow v. Emergency Med. of Idaho, P.A., we addressed our holding in
Sheridan, stating that, “we did not hold that expert testimony is never necessary in order to prove
causation in a medical malpractice case. We simply held that expert testimony that the nurses’
negligence was a proximate cause of the child’s injuries was not required under the facts of that
particular case.” 138 Idaho 589, 596, 67 P.3d 68, 75 (2003). In Swallow, this Court held that
expert testimony was necessary to prove whether an excessive dose of Cipro given to the
plaintiff was a cause of his heart attack because “it is a matter of science that is far removed from
the usual and ordinary experience of the average person. A jury, comprised of lay people, is
simply not qualified to determine that issue without the assistance of expert testimony that Cipro
can cause a myocardial infarction.” Id. at 598, 67 P.3d at 77.
        Easterling argues that the present case is like Sheridan, in that her claim is based on
whether the failure to treat her caused a particular injury. Easterling contends that evidence was
presented showing that a natural consequence of a carotid artery dissection is a stroke and
Easterling, in fact, suffered a stroke after being discharged and prior to being properly diagnosed
and treated on September 6. Easterling also contends that the fact that she was treated with
anticoagulants on September 6 is sufficient to show that anticoagulant treatment would have
been appropriate on September 5.



                                                 18
        There is no bright-line rule to determine whether expert testimony is required to prove
proximate cause. The inquiry is highly dependent on the specific circumstances of each case. See
id. at 596, 67 P.3d at 75. Here, the evidence presented at trial does not provide a chain of
circumstances upon which a lay person could infer that Kendall’s misdiagnosis was a substantial
factor in causing Easterling’s injuries. Although Easterling presented evidence that anticoagulant
treatment was used on September 6, that fact has little bearing on whether anticoagulant
treatment would have been appropriate on the September 5 or whether the delay in starting such
treatment had any impact on Easterling’s injuries. This is especially true where it is undisputed
that Easterling continued to suffer strokes while on anticoagulant treatment. Easterling did suffer
a stroke after being discharged on September 5 and before beginning treatment on the 6th.
However, there is no evidence on the record as to what impact beginning treatment on September
5 may have had. Whether anticoagulant treatment would have been more effective if started
before Easterling experienced a stroke on September 6 is a highly-technical medical question
which requires the testimony of medical experts in order for a reasonable jury to find proximate
cause. Easterling presented no evidence from which a lay person could infer that the course of
Easterling’s treatment and her ultimate injuries would have been any different had Kendall
diagnosed her with a carotid artery dissection and started treatment on September 5. In this case,
a jury comprised of lay people is not qualified to determine whether Kendall’s misdiagnosis and
the resulting delay in Easterling’s treatment was a substantial factor in causing her injuries. The
district court, therefore, did not err in granting Kendall’s motion for a directed verdict.
    5. The district court abused its discretion in awarding Kendall discretionary costs.
        Under Idaho Rule of Civil Procedure 54(d)(1)(D), “[a] trial court may, in its discretion,
award a prevailing party certain costs where there has been a showing that the costs are
necessary and exceptional, reasonably incurred, and should in the interests of justice be assessed
against the adverse party.” Hayden Lake Fire Prot. Dist. v. Alcorn, 141 Idaho 307, 314, 109 P.3d
161, 168 (2005) (internal quotation marks omitted). The party opposing an award of
discretionary costs bears the burden of demonstrating that the district court abused its discretion.
Id. To survive appeal, an award of discretionary costs must include “[e]xpress findings as to the
general character of requested costs and whether such costs are necessary, reasonable,
exceptional, and in the interests of justice.” Id.




                                                     19
       Whether discretionary costs, including expert witness fees, are “exceptional” depends on
whether “the nature of the case was itself exceptional.” Id. Because expert testimony is required
in every medical malpractice case, expert witness fees in these cases are generally considered
ordinary—not exceptional. Nightengale v. Timmel, 151 Idaho 347, 355, 256 P.3d 755, 763
(2011). “Absent other findings, there is no basis for every expert witness’ testimony to be
considered ‘exceptional’ simply because it requires specialized knowledge.” Id. “The mere fact
numerous experts were retained or numerous amendments were filed does not standing alone
render a case exceptional.” Hoagland v. Ada Cnty., 154 Idaho 900, 914, 303 P.3d 587, 601
(2013). In Hoagland, this Court set forth factors a district court should consider when
determining whether costs are exceptional: “whether there was unnecessary duplication of work,
whether there was an unnecessary waste of time, the frivolity of issues presented, and creation of
unnecessary cost that could have been easily avoided. Most importantly, however, a court should
explain why the circumstances of a case render it exceptional.” Id. (emphasis in original).
       Here, the district court recognized that this issue was one of discretion. However, the
district court did not reach its determination that the costs awarded were exceptional through an
exercise of reason and its award of costs was outside the bounds of its discretion. The district
court granted Kendall $49,463.94 in discretionary costs based on the expenses Kendall incurred
in retaining his causation experts beginning in December 2013. The district court relied on
Lakeland True Value Hardware, LLC v. Hartford Fire Ins. Co., where this Court held that a
party’s conduct may support an award of discretionary costs. 153 Idaho 716, 730, 291 P.3d 399,
413 (2012). The district court found that Easterling failed to timely identify a retained causation
expert and provided misleading information about the treating physicians’ opinions on causation,
and those decisions exacerbated costs incurred by Kendall. Additionally, the district court found
that because the nature of Easterling’s injury and treatment were complex, expert testimony on
causation was necessary for her to prove causation and her decision not to retain a causation
expert impacted the costs to Kendall.
       Easterling contends that Kendall’s expert fees were not “exceptional” because they were
not incurred because of Easterling's failure to provide expert causation testimony or Easterling’s
discovery violations. Easterling contends that Kendall would have had to hire these experts even
if Easterling had properly retained and disclosed a causation expert and that the district court did
not explain how the alleged discovery violations increased the costs of retaining such experts.



                                                20
       The district court failed to provide an explanation for how Easterling’s discovery
decisions made Kendall’s expert witness fees exceptional. In medical malpractice cases it is
necessary for the parties to provide expert testimony. As argued by Easterling, Kendall would
have had to hire causation experts even if Easterling had properly retained her own causation
expert. The district court did not provide an explanation for how Easterling’s discovery decisions
transformed normal costs of malpractice defense—expert witness fees and expenses—into
exceptional ones.
       The district court also found that Idaho Rule of Civil Procedure 11(a)(1) was an
alternative basis for awarding discretionary costs to Kendall. Rule 11(a)(1) provides that:
       The signature of an attorney or party constitutes a certificate that the attorney or
       party has read the pleading motion or other paper; that to the best of the signor’s
       knowledge, information, and belief after reasonable inquiry it is well grounded in
       fact and is warranted by existing law … and that is not interposed for any
       improper purpose, such as to harass or to cause unnecessary delay or needless
       increase in the cost of litigation.
I.R.C.P. 11(a)(1). The district court found that Easterling’s counsel violated Rule 11(a)(1) by
filing discovery responses purporting to include the treating physicians’ opinions on causation
when Easterling’s counsel had not even spoken to the treating physicians on this issue. Easterling
argues that there was no Rule 11(a)(1) violation because Interrogatory No. 3 only asked for what
counsel expected the treating physicians opinions to be and, therefore, her response comports
with Rule 26.
       Regardless of whether Easterling’s counsel violated Rule 11(a)(1), the district court
abused its discretion in awarding Kendall his expert witness fees and costs as the sanction for
this perceived violation. Idaho Rule of Civil Procedure 11(a)(1) “is a court-management tool,
meant to focus on discrete pleading abuses or other types of litigation misconduct.” State v.
Keithly, 155 Idaho 464, 468, 314 P.3d 146, 150 (2013). The district court has the authority to
impose an “appropriate sanction” against an attorney or represented party for violating Rule 11,
including the costs or expenses incurred by the other party because of the filing. I.R.C.P.
11(a)(1). Rule 11 does not provide a basis to award costs against a party that are completely
unrelated to the alleged violation. Kendall’s costs for retaining expert witnesses did not arise
from the misrepresentation, and are not an appropriate sanction under Rule 11(a). The district
court abused its discretion in awarding Kendall his causation expert fees and expenses as
discretionary costs. We therefore vacate the award of discretionary costs.


                                                21
   6. Kendall is not entitled to attorney fees on appeal.
       The Court will award fees to a prevailing party under Idaho Code section 12-121 when
the Court believes “that the action was pursued, defended, or brought frivolously, unreasonably,
or without foundation.” Idaho Military Historical Soc’y, Inc. v. Maslen, 156 Idaho 624, 633, 329
P.3d 1072, 1081 (2014) (citation and internal quotation marks omitted). Fees will generally not
be awarded for arguments that are based on a good faith legal argument. Id. Here, Easterling
raised good faith legal arguments as to the district court’s award of discretionary costs and the
district court’s grant of directed verdict. This appeal was not frivolous, unreasonable, or without
foundation. Therefore, we decline to award Kendall attorney fees on appeal.
                                            IV.
                                         CONCLUSION
       We affirm the district court’s decisions to grant a directed verdict to Kendall, to exclude
Easterling’s expert opinion testimony on causation, and to deny Easterling’s motion to present
rebuttal evidence in her case in chief. We vacate the district court’s award of discretionary costs
to Kendall. No costs or attorney fees to either party on appeal.


       Justices EISMANN, BURDICK, W. JONES and HORTON CONCUR.




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