Case Title: Marcum v. Adventist Health System/West

Citation: 

Docket Number: S055431

State: oregon

Court: Oregon Supreme Court

Date: 2008-09-16T00:00:00Z

Document:
FILED: September 16, 2008
IN THE SUPREME COURT OF THE STATE OF OREGON
DEBORAH MARCUM, 
Petitioner
on Review, 
v. 
ADVENTIST HEALTH SYSTEM/WEST,
a foreign corporation,
dba Adventist Health;
NORTHWEST MEDICAL FOUNDATION OF TILLAMOOK,
an Oregon corporation,
dba Tillamook County General Hospital;
ALLIANCE IMAGING, INC.,
a foreign corporation;
ALLIANCE IMAGING MANAGEMENT, INC.,
a foreign corporation;
and ALLIANCE IMAGING CENTERS, INC.,
a foreign corporation, 
Respondents
on Review.
(CC
040505205; CA A129660; SC S055431)
En Banc          
On review from the
Court of Appeals.*
Argued and submitted
June 4, 2008.
Jeffrey B. Wihtol,
Portland, argued the cause and filed the brief for petitioner on review.
Janet M. Schroer,
Hoffman Hart & Wagner, LLP, Portland, and Lisa E. Lear, Bullivant Houser
Bailey, P.C., Portland, argued the cause and filed the brief for respondents on
review.  With them on the brief was Marjorie A. Speirs, Hoffman Hart &
Wagner, LLP, Portland.
Linda K. Eyerman,
Gaylord Eyerman Bradley, P.C., Portland, filed the brief for amicus curiae Oregon
Trial Lawyers Association.  With her on the brief was Leslie W. O'Leary,
Williams Love O'Leary & Powers, Portland.
BALMER, J.
The decision of the
Court of Appeals is reversed.  The case is remanded to the Court of Appeals for
further proceedings.
*Appeal from
Multnomah County Circuit Court, George A. Van Hoomissen, Senior Judge. 215 Or
App 166, 168 P3d 1214 (2007).
BALMER, J.
This medical malpractice action
requires us to review and apply the standards for admission of expert medical
testimony.  Under the applicable evidentiary rules, as interpreted in this
court's cases, an expert's medical testimony must meet a test of
"scientific validity."  Plaintiff here experienced symptoms of pain,
swelling, and discoloration in her left hand immediately after injection of a
chemical called gadolinium; her pain and the discoloration have continued.  At trial,
plaintiff proffered the testimony of a medical expert that the gadolinium,
instead of going into the vein, went into an area of her hand outside the vein,
a circumstance known as "extravasation."  As a result, according to
the expert, the toxicity of the gadolinium caused both her immediate and her
ongoing symptoms.  Defendants objected to the expert's proffered testimony, and
the trial court ruled that the testimony did not meet the legal standard for
scientific validity.  The Court of Appeals affirmed.  Marcum v. Adventist
Health System/West, 215 Or App 166, 168 P3d 1214 (2007).  We granted review
and now reverse.
The Court of Appeals described the
facts and the procedural background of the case:
"In March 2003, after plaintiff was involved in an auto
accident, suffering a possible head injury, her doctor ordered an MRI. 
Plaintiff went to Tillamook County General Hospital and was escorted to an MRI
trailer just outside.  The MRI technologist, employed by Alliance, informed
plaintiff that he would be injecting her with a contrast chemical, gadolinium,
used to enhance the MRI image.
"Alliance's MRI technologists are trained
to advise patients that, if the injection of a contrast chemical causes pain or
any other discomfort, they should immediately inform the technologist.  If a
patient makes such a complaint, the technologists are trained to check for
extravasation.  'Extravasation' occurs when a substance exits the vein and
enters the surrounding tissue.  See Stedman's Medical Dictionary 635
(27th ed 2000) (defining 'extravasate' as, inter alia, '[t]o exude from
or pass out of a vessel into the tissues').  The general standard of care
applicable to MRI technologists requires that they explain the procedure to the
patient and ask the patient to inform them if they feel pain.  However, neither
plaintiff's technologist nor her treating physician explained the injection
procedure, asked her to report pain, or explained to her any risks associated
with the injection.
"After attempting the injection on each of
plaintiff's arms unsuccessfully, the technologist attempted to make the
injection on the back of plaintiff's left hand.  Immediately after the needle
went into her hand, plaintiff complained that her hand felt 'like a glove
filling up.'  She explained to the technologist that 'if he was to take the tip
of my fingers off he would see the stuff running on the floor.  That's how full
it felt.'  The technologist acknowledged plaintiff's complaint but told her it
would be okay and finished the procedure.
"Plaintiff manages a restaurant.  She
normally performs various functions in the business, including food
preparation, which involves going to the restaurant's walk-in refrigerator. 
The day after the MRI, however, when she went to the walk-in refrigerator she
had a difficult time handling the cold food and complained that her left hand
hurt.  Her coworker described her hand as appearing purple, orange, and
swollen.  After a couple of hours, plaintiff went to the emergency room.  She
has experienced pain ever since, which has impaired her ability to work. 
Plaintiff's hand has remained discolored near where she received the gadolinium
injection.
"* * * * *
"Plaintiff filed this action against
defendants.  In her operative complaint, she alleged that defendants had
negligently injured her and negligently failed to obtain her informed consent
before injecting her with gadolinium.  * * *
"[A]t trial, the court excluded portions of
the testimony of plaintiff's two expert witnesses, Dr. Weldon Williamson and
Karen Marburger.  Williamson, a medical doctor specializing in hand disorders,
would have testified concerning medical causation.  Marburger, an MRI
technologist, would have testified that defendants should have made and kept
various records and that, had plaintiff been able to obtain those records, they
might have been beneficial in proving plaintiff's claims.
"With respect to Williamson's testimony,
the court held an OEC 104 hearing to determine whether Williamson's opinion
regarding causation--specifically that gadolinium extravasation caused
plaintiff's [vasospastic disorder(1)]
--was 'scientifically valid' under the standards prescribed in [State v.]
Brown [, 297 Or 404, 687 P2d 751 (1984)] and [State v.] O'Key
[, 321 Or 285, 899 P2d 663 (1995)].  The court ultimately concluded that that
testimony did not satisfy the requisites of foundational admissibility.  * * *
"Defendants moved for a directed verdict on
plaintiff's medical negligence claim based on plaintiff's failure to produce
evidence of causation.  Plaintiff, while maintaining that the exclusion of
Williamson's testimony was error, agreed that without that testimony, she had
not produced evidence of causation.  * * * The court directed a verdict in
defendants' favor * * * and entered judgment accordingly."
Marcum, 215 Or App at 169-72.
Plaintiff appealed, and the Court of
Appeals affirmed.  The central issue on appeal was whether the testimony of
plaintiff's expert as to the likely cause of plaintiff's injury met the test of
scientific validity.(2) The Court of Appeals reasoned that the expert had failed to identify a
scientifically valid cause of the injury -- one that linked plaintiff's exposure
to gadolinium to the vasospastic disorder that she experienced.  In particular,
the court noted that the expert had failed to show, either through studies
showing a high degree of correlation between gadolinium exposure and the kind
of injury that plaintiff had suffered or through a scientifically
demonstrable mechanism of causation, that the gadolinium extravasation could
have caused plaintiff's vasospastic disorder.  Id. at 184-88. 
Judge Armstrong dissented.  While conceding that the issue was a close one, he thought
that the expert's testimony was sufficiently scientific in nature and helpful
to the trier of fact to warrant its admission.  Id. at 193-98
(Armstrong, J., concurring in part, dissenting in part).(3)
We begin by reviewing the standards
that this court has used to determine whether scientific evidence will be
admitted.  In Jennings v. Baxter Healthcare Corp., 331 Or 285, 301, 14
P3d 596 (2000), the court noted that its prior cases had held that expert
testimony is admissible if it is relevant under OEC 401,(4) would
assist the trier of fact under OEC 702(5) and is not subject to exclusion under OEC 403(6) because its probative value is outweighed by the danger of unfair prejudice or
jury confusion.  In this case, as in many others involving the admissibility of
scientific evidence, we must determine "whether scientific evidence is
probative under OEC 401" and conduct the "'relevancy and prejudice
analysis implicated in OEC 702's helpfulness standard[.]'"  Jennings,
331 Or at 302 (quoting Brown, 297 Or at 417); see also Brown, 297
Or at 409 (court must "identify and evaluate the probative value of the
evidence, consider how it might impair rather than help the factfinder, and
decide whether truthfinding is better served by exclusion or admission").
In O'Key, 321 Or at 291, this
court explained the principles underlying the application of the evidentiary
rules to scientific evidence:
"Evidence perceived by lay jurors to be
scientific in nature possesses an unusually high degree of persuasive power. 
The function of the court is to ensure that the persuasive appeal is
legitimate.  The value of proffered expert scientific testimony critically
depends on the scientific validity of the general propositions utilized by the
expert."
(Footnote omitted.)  In ruling on admissibility, the trial
court performs the "vital role" of "gatekeeper," id.
at 307, screening proffered scientific testimony to determine whether it is
sufficiently valid, as a matter of science, to legitimately assist the trier of
fact and "exclud[ing] 'bad science' in order to control the flow of
confusing, misleading, erroneous, prejudicial, or useless information to the
trier of fact."  Id. at 306.
This court has set out a number of
factors that may be considered in determining the admissibility of scientific
evidence:  
"(1)  The technique's general acceptance in the field; 
"(2)  The expert's qualifications and stature; 
"(3)  The use which has been made of the technique; 
"(4)  The potential rate of error; 
"(5)  The existence of specialized literature; 
"(6)  The novelty of the invention [if one is involved];
and 
"(7)  The extent to which the technique relies on the
subjective interpretation of the expert."(7)
Brown, 297 Or at 417.  Those factors, however, are not
an "exclusive checklist," Jennings, 331 Or at 302, and the
"existence or nonexistence" of any particular factor may enter into
the final decision on admissibility, "but need not necessarily do so." 
Id. at 303 (quoting Brown, 297 Or at 417-18).  Underlying the
various considerations and factors described by the court is the fundamental
question of the "'scientific validity of the general propositions utilized
by the expert.'"  Jennings, 331 Or at 303 (quoting O'Key,
321 Or at 291).
This court has applied the foregoing
principles to determine the admissibility of scientific evidence in several
cases.  The parties discuss in detail this court's decisions in Brown, where
the court considered the admissibility of polygraph evidence, and O'Key,
where the court evaluated the admissibility of the Horizontal Gaze Nystagmus
(HGN) test as a preliminary method of determining whether a defendant might be under
the influence of intoxicants.  As the citations to those cases in the
discussion above shows, the cases are helpful in the sense that they describe
the general rules for admissibility of scientific evidence.  However, they
provide limited guidance in deciding the issue before us, because both Brown
and O'Key involved the admissibility of specific techniques or tests,
the validity of which turned on scientific principles.(8)  Here, in
contrast, the expert testimony at issue focuses on medical causation --
specifically, whether plaintiff's injuries were caused by the gadolinium that
was injected into her hand -- and the question is whether the proffered expert testimony
about causation meets the standard of scientific validity.  That is, the issue
is the scientific basis for the causation testimony, rather than the scientific
basis for a particular technique or method.
This court considered the
admissibility of expert medical testimony as to causation in Jennings. 
There, the plaintiff proffered expert testimony that her neurological
problems were caused by silicone that had leaked from silicone breast implants. 
The expert had examined approximately 50 women, many of whom had inner-ear
balance problems and loss of sensation in their extremities after exposure to
silicone.  The expert testified that "the unique thing was that there was
an extraordinarily high correlation, 95 percent had the combination of unusual
sensory patterns and the inner ear [problem]."  331 Or at 290.  As part of
his analysis, the expert performed a "differential diagnosis," in
which he considered various potential causes of the symptoms and then ruled out
all but one, the exposure to silicone.  Id. at 291 ("In a
differential diagnosis, a doctor develops a list of all diseases that might
cause a patient's symptoms and then, by a process of elimination, narrows the
list.").  Although no published studies, peer-reviewed publications, or
medical consensus supported his testimony as to causation, id. at 292-93,
this court held that the testimony should have been admitted.  "Although
[the expert's] hypothesis has not been tested by others, that is, in part,
because his work is new."  Id. at 307.  
Two aspects of Jennings are pertinent
to this case.  First, this court expressly permitted the use of
"differential diagnosis" as a means of determining medical
causation.  Second, the court concluded that OEC 702 does not automatically preclude
the admission of "novel" scientific evidence:  "If it is
otherwise scientifically valid, a novel conclusion is admissible."  331 Or
at 307.  Thus, although published studies and acceptance of the theory in the
medical community are relevant considerations, their absence in that case did not
mean that the expert's scientific testimony as to causation had to be
excluded.  The expert in Jennings could not explain the mechanism by
which silicone had caused the neurological problems, but he reported a high
correlation between exposure to silicone and the specific neurological symptoms
in the women whom he had studied.  From that correlation and the elimination of
other possible causes of the symptoms, the expert reached the conclusion that the
exposure to silicone had been the likely cause of the plaintiff's symptoms.  This
court concluded that the expert testimony on causation was scientifically valid
and should have been admitted.  331 Or at 305.
We turn to the application of those
principles to the expert testimony here.  As noted, in Jennings, this
court recognized that "differential diagnosis"(9) is an
accepted technique in which "a doctor develops a list of all diseases that
might cause a patient's symptoms and then, by a process of elimination, narrows
the list."  331 Or at 291 (citing Mary Sue Henifin, Howard M. Kipen, and
Susan R. Poulter, Reference Guide on Medical Testimony, in Reference
Manual on Scientific Evidence 439, 463 (Federal Judicial Center ed., 2d
ed 2000)).  Put differently, differential diagnosis involves a process by which
a medical expert first "rules in" various potential causes and then
"rules out" those causes one by one (to the extent possible) by analyzing
the patient's condition until the expert can identify the likely cause from
among those remaining.  Thus, "differential diagnosis" is a general
description of a methodology or process accepted by the medical community as a
means of determining causation (or condition), rather than a specific
scientific technique or test, such as the HGN test considered in O'Key or
the use of polymerase chain reaction-based DNA testing at issue in State v.
Lyons, 324 Or 256, 924 P2d 802 (1996).  For that reason, although
differential diagnosis can be the basis for admissible expert testimony
as to medical causation, testimony is not admissible simply because the expert
conducted a differential diagnosis.  Rather, admissibility will turn on whether
the particular use of differential diagnosis to determine causation meets the
more general test of scientific validity.  See Jennings, 331 Or at
305-10 (concluding, after reviewing expert's basis for including and excluding
potential causes of plaintiff's condition, that differential diagnosis provided
sufficient basis for expert to testify that silicone exposure was likely cause
of the plaintiff's condition).  
We also recognize, as did the Court
of Appeals, that differential diagnosis of medical causation often cannot lead
an expert to conclude, with certainty, that event "A" caused
condition "B."(10) 
Rather, in many cases, a number of potential causes will be "ruled
in," each of which has some percentage of likelihood of having caused
plaintiff's condition; then the expert, by physical examination, testing, or
other scientifically valid process, eliminates one or more of the potential
causes in an effort to identify the actual cause.  Even if the expert is not
able to eliminate all alternative causes, the testimony nevertheless may
be reliable and admissible if sufficient potential causes are eliminated for
the expert to identify one particular cause as the likely cause of the
condition.  See Note, Navigating Uncertainty:  Gatekeeping in the
Absence of Hard Science, 113 Harv L Rev 1467, 1474 (2000) (courts generally
allow admission of differential diagnosis even when technique has not eliminated
all alternative causes).
Moreover, the basis for establishing
the scientific validity of a differential diagnosis will vary depending on the
type of injury.  In the typical toxic tort case, there may be "a
complicated causal chain, a long latency period, or low levels of exposure * * *."  Note, 113 Harv L Rev at 1472.  In those
circumstances, reliable testimony on causation may require "extremely
accurate data and methods," peer-reviewed studies, and small and
controlled error rates to "rule in" a possible cause.  Id; see
also id. at 1480 ("[O]ther characteristics of the generic toxic tort
-- a long latency period, complicated biological explanation, and lack of a
single sharp exposure event -- are likely to make alternative causes seem both
substantially probable and difficult to exclude.").  In contrast, when the
exposure occurs in a single, sharp event, and the injury is immediate and
localized, it may be appropriate to "rule in" the exposure as one of
the possible causes of the injury, particularly when there are few obvious
alternative causes.  Id. at 1473 (describing circumstances in which
toxic exposure may be considered as cause of plaintiff's injuries, even in the
absence of epidemiological studies).  Of course, when "ruling in"
potential causes of a condition or injury for purposes of differential
diagnosis, a trial court should insist that the causation theory be "biologically
plausible," that is, that the exposure could have caused
plaintiff's injury.  Id. at 1475 (citing Reference Manual on
Scientific Evidence at 163, 204); see also Jennings, 331 Or at 309
("'What is biologically plausible depends upon the biological knowledge of
the day.'" (Quoting Hill, The Environment and Disease:  Association or
Causation?, 58 Proc R Soc Med 295, 298 (1965).)).  For that reason, a
particular possible cause should not necessarily be excluded on the grounds
that the expert cannot describe the precise mechanism of causation or point to
statistical studies of cause and effect.  See Jennings, 331 Or at 309
("There are many generally accepted hypotheses in science for which the mechanism
of cause and effect is not understood fully.").
In this case, the Court of Appeals
accepted the concept of differential diagnosis but concluded that there was no
scientific basis for plaintiff's expert to "rule in" gadolinium
exposure as a possible cause of plaintiff's symptoms.  Marcum, 215 Or
App at 181-82, 187.  The court reached that conclusion because, in its view,
the expert's testimony did not meet the standard required for scientific
validity:
"Either the expert must be able to identify a
scientifically demonstrable mechanism of causation or there must be some
independent, verifiable corroboration of otherwise inexplicable causation, as
in Jennings.  Where, however, a plaintiff's circumstances are unique and
the expert cannot proffer a mechanism of causation, general temporal and
spatial proximity to the onset of symptoms, even when coupled with reports of
other adverse effects, is insufficient."
Id. at 187.  Because there was no basis to "rule
in" gadolinium extravasation as a cause of plaintiff's injuries, the court
reasoned, the expert's elimination of other potential causes and his subsequent
conclusion that gadolinium extravasation likely had caused the injuries was
inadmissible.  Id. 
In reaching that conclusion, the
Court of Appeals cited the appropriate tests identified in Brown,
O'Key, and Jennings, but we think that it applied them in too
rigorous a manner, given the context of this case.  The court seemed to suggest
that, in the absence of a well-understood mechanism of causation or a study
demonstrating a high correlation between exposure and injury, testimony as to
causation is not permitted because the possible cause never could be "ruled
in" for purposes of a differential diagnosis.  
In Jennings, however, this
court concluded that the expert's inability to explain the mechanism of
plaintiff's condition in that case went to the weight, not to the admissibility,
of the evidence.  331 Or at 309.  And, although plaintiff's expert here could
not point to studies demonstrating a correlation between gadolinium
extravasation and vasospastic disorder in the hand, our discussion above of the
use of differential diagnosis shows that the absence of such studies does not
necessarily preclude "ruling in" that exposure as a possible cause of
plaintiff's injuries.  With that discussion in mind, we return to the expert testimony
at issue here.  
Plaintiff's expert identified a
number of reasons that he "ruled in" gadolinium extravasation as a
potential cause of plaintiff's vasospastic disorder:  Her symptoms occurred
almost immediately after the injection and in the same area as the injection. 
Her description of her sensations during the injection was consistent with
extravasation, and she had no symptoms prior to the injection.  Published
medical literature suggested that gadolinium exposure can be toxic to tissue in
mice, that it can cause inflammation and necrosis (tissue death), and that
those toxic effects are likely increased by extravasation because the body has
greater difficulty excreting a substance when it is located outside the
arterial system.  Although plaintiff's expert did not diagnose necrosis in
plaintiff's hand, he testified that plaintiff may have necrosis under the
skin.  The expert also testified that no studies existed linking gadolinium to
vasospastic disorder and that no studies were likely to be done because
gadolinium extravasation is rare, and particularly so in the hand, as contrast
chemicals used in MRI examinations ordinarily are not injected into the hand.
Plaintiff's expert also testified as
to the scientific reasons that he "ruled out" other possible causes
of plaintiff's symptoms.  Notably, he ruled out an ordinary case of Raynaud's
syndrome itself, because that syndrome almost always appears in both hands
(bilaterally), while plaintiff's symptoms manifested themselves only in the
hand where the injection had occurred.  Through blood tests and other diagnoses,
he ruled out other potential causes of plaintiff's symptoms, including
connective tissue and autoimmune disorders, such as lupus.  He also ruled out
allergic or hypersensitivity reactions to the gadolinium.  Based on his
research, examination, and tests, plaintiff's expert concluded that plaintiff's
symptoms probably were caused by gadolinium extravasation.
As noted, after reviewing that
proffered testimony, the Court of Appeals concluded that it lacked scientific
validity because the expert was unable to "identify a scientifically
demonstrable mechanism of causation" or provide "some independent,
verifiable correlation of otherwise inexplicable causation[.]"  Marcum,
215 Or App at 187.  A brief discussion of the court's reasoning demonstrates
why we conclude that it took too narrow a view in considering the scientific
validity of that testimony.  First, as to the "mechanism of
causation" standard, plaintiff's expert testified that the cause of
Raynaud's syndrome (vasospastic disorder) has not been established in the
medical community -- that is, the condition can be identified, but its
mechanism of causation is unknown.(11) 
He also testified that there was nothing in the medical literature to suggest
that gadolinium could not cause plaintiff's symptoms.  See Jennings,
331 Or at 309 (expert's opinion as to causation had not been accepted by the
scientific community, but neither had it been rejected).  Finally, the expert
pointed to tests on mice that showed that the injection of gadolinium was toxic
to tissue, causing inflammation and necrosis.  He further explained that the
studies showed that the toxicity was related to the duration of exposure and
that the extravasation would have made the gadolinium more toxic to plaintiff
because it would have remained in her system longer than if it had been
properly injected.  
Second, the Court of Appeals
certainly was correct in noting that "independent, verifiable
corroboration" can be critical in demonstrating "otherwise
inexplicable causation."  Marcum, 215 Or App at 187.  However,
injuries may be rare or unique, as plaintiff's injury was here, and, for that
reason or because of ethical or other considerations, studies and comparisons
may not be possible.  As discussed above, if other legitimate grounds for
"ruling in" a potential cause exist, as they do here, then the
absence of corroboration is not, itself, necessarily grounds for exclusion. 
It follows from the foregoing that, by
focusing narrowly on the absence of a scientifically accepted mechanism of
causation or other verifiable correlation, the Court of Appeals asked for too
much.  More specifically, the court disregarded the potential connection
between the gadolinium extravasation and plaintiff's injuries, because, in that
court's view, that potential cause could not be "ruled in."  Although
the court was properly concerned with avoiding the logical fallacy of post
hoc, ergo propter hoc (after this, therefore because of this) reasoning, it
failed to give appropriate deference to the expert witness's reliance upon
plaintiff's sudden, single exposure and her immediate, localized symptoms, as
well as to the biological plausibility of the expert's causation theory.  The
immediate symptoms that plaintiff experienced in her hand indicate a causal
link between the exposure and her symptoms, and her expert's careful
differential diagnosis supports that connection.  Moreover, the expert's
reliance on studies demonstrating the toxicity of gadolinium provide a
biologically plausible basis for his conclusion.  Applying the criteria
identified above, we agree with plaintiff that she had made an adequate showing
of a scientifically valid basis for "ruling in" gadolinium as a
potential cause of her symptoms, as well as for "ruling out" a number
of the other possible causes of her injury.  The jury should have been permitted
to hear the expert's testimony that, in his opinion, the gadolinium
extravasation caused that injury.
Defendants argue that permitting
plaintiff's expert to offer his opinion as to causation in the absence of a
scientifically demonstrable mechanism of causation or studies demonstrating a
high degree of correlation between cause and effect undermines this court's
emphasis on the requirement of scientifically valid expert testimony.  In
particular, they imply that such a decision would permit experts to speculate
on the causal connection between even brief exposure to toxic substances and
later physical symptoms.  That concern is misplaced.  Here, the exposure event
was direct and abrupt, and the symptoms were immediate and localized.  In those
circumstances, and given the acknowledged expertise and skill of plaintiff's medical
witness, his reliance on the temporal and spatial relationships between the
exposure and the symptoms (along with the other facts described above) and the
biological plausibility of his conclusion as to causation support the
scientific validity of his testimony.  See generally Note, 113 Harv L
Rev at 1484 (significance of differential diagnosis and temporal proximity is
inherently contextual and depends on sharpness of exposure event, among other
things).  
The testimony of plaintiff's expert
should have been admitted.  Questions as to the weight to be given that
testimony, possible weaknesses in the expert's theory, and the ultimate issue
of causation were for the jury to decide based on all the evidence.
Based on its decision regarding
Williamson's testimony, the Court of Appeals affirmed the trial court's
directed verdict on plaintiff's negligence claim and on her informed consent
claim.  Our disposition of the evidentiary issue means that we reverse the
lower court rulings with respect to the negligence claim.  Defendants, however,
advanced alternative arguments before the Court of Appeals as to why the
directed verdict on the informed consent claim was proper.  The Court of
Appeals has not considered those arguments, and we therefore remand to that court
so that it may consider them.
The decision of the Court of Appeals
is reversed.  The case is remanded to the Court of Appeals for further
proceedings.
1. The
parties sometimes refer to plaintiff's condition as "vasospasm,"
"digital artery disease," or as "similar" to Raynaud's syndrome,
a condition in which an artery "clamps down" abnormally in response
to cold.  It is undisputed that plaintiff suffered some kind of immediate
injury to her hand at the time of the injection and that she continued to
experience symptoms of vasospastic disorder.
2. The
parties do not dispute the professional qualifications of plaintiff's expert,
Williamson, who is a vascular surgeon and a member of the Department of
Vascular Surgery at Oregon Health and Sciences University.  Williamson is an
expert on the treatment of vascular impairment to the hands and fingers and has
done substantial research in the area and published book chapters and journal
articles on that subject.  He is also the author of a chapter in a 1998 medical
textbook on the methodology for differentiating the causes of vascular problems
in the hand and fingers.  The parties also do not disagree as to Williamson's diagnosis
of plaintiff's condition.  The sole dispute concerns his testimony as to the cause
of plaintiff's condition and whether his expertise permits an opinion as to
that cause.
3. The
Court of Appeals also rejected two assignments of error related to the alleged
spoliation of evidence.  Plaintiff did not petition for review of those issues,
and we do not consider them.
4. OEC 401 provides:
"'Relevant evidence' means evidence having
any tendency to make the existence of any fact that is of consequence to the
determination of the action more probable or less probable than it would be
without the evidence."
5. OEC 702 provides:
"If scientific, technical or other
specialized knowledge will assist the trier of fact to understand the evidence
or to determine a fact in issue, a witness qualified as an expert by knowledge,
skill, experience, training or education may testify thereto in the form of an
opinion or otherwise."
6. OEC 403 provides:
"Although relevant, evidence may be
excluded if its probative value is substantially outweighed by the danger of
unfair prejudice, confusion of the issues, or misleading the jury, or by
considerations of undue delay or needless presentation of cumulative
evidence."
7. To
that list, the court joined 11 additional considerations:  
"(1)  The potential error rate in using the technique; 
"(2)  The existence and maintenance of standards
governing its use; 
"(3)  Presence of safeguards in the characteristics of
the technique; 
"(4)  Analogy to other scientific techniques whose
results are admissible; 
"(5)  The extent to which the technique has been
accepted by scientists in the field involved; 
"(6)  The nature and breadth of the inference adduced; 
"(7)  The clarity and simplicity with which the
technique can be described and its results explained; 
"(8)  The extent to which the basic data are verifiable
by the court and jury; 
"(9)  The availability of other experts to test and
evaluate the technique; 
"(10)  The probative significance of the evidence in
the circumstances of the case; and 
"(11)  The care with which the technique was employed
in the case."  
Brown, 297 Or at 417 n 5.
8. For
that reason, the court in Brown phrased many of the factors to be
considered in determining admissibility with reference to the
"technique" of polygraph analysis -- whether the
"technique" was generally accepted in the field, the potential error
for the "technique," and so on.  Brown, 297 Or at 417, 417 n
5.  Similarly, the court in O'Key consistently phrased the standard for
admissibility and its application of that standard as whether the HGN
"test" was generally accepted and was the subject of specialized
scientific literature, among other considerations.  O'Key, 321 Or
at 306, 314-19 (stating and applying standard).
9. We recognize, as did the Court of Appeals, Marcum v. Adventist
Health System/West, 215 Or App 166, 175 n 5, 168 P3d 1214 (2007), that the
term "differential diagnosis" is more properly used to describe the
process of determining the disease or symptoms from which a patient is
suffering, rather than the process of determining the external cause of
the disease or symptoms, and that "differential etiology" is a more
precise description of the latter.  See Mary Sue Henifin, Howard M.
Kipen, and Susan R. Poulter, Reference Guide on Medical Testimony, in Reference
Manual on Scientific Evidence 439, 481 (Federal Judicial Center ed., 2d
ed 2000) (defining those terms).  However, given the widespread use of the term
"differential diagnosis" to apply to determinations of causation as
well as of disease or symptoms, we use that term here.  Further, we reject
defendants' argument that Williamson lacks expertise in "differential
etiology."  We need not decide whether, as plaintiffs argue, all doctors
have expertise in differential etiology as well as differential diagnosis.  It
is sufficient in this case to say that Williamson had expertise in the
causation of vascular disorders of the extremities.
10. Of
course, expert testimony of causation is sufficient if it establishes that
defendant's conduct was the likely cause of plaintiff's injury;
certainty is not required.  See Joshi v. Providence Health System,
342 Or 152, 159, 149 P3d 1164 (2006) (causation in wrongful death action
requires proof that defendant's acts or omissions "more likely than
not" caused plaintiff's injuries).
11. Although
the Court of Appeals viewed that fact as a critical reason not to "rule
in" gadolinium exposure as a possible cause of plaintiff's symptoms, that
fact had to be weighed with the other grounds that the expert gave for
"ruling in" that exposure.  It is the combination of facts that we
review.