Citations and pin cites are based on the Westlaw online version of the cited material.

IN THE COURT OF APPEALS OF THE STATE OF WASHINGTON

ARTHUR R. SOUCY, an individual,

Appellant,

v.

DR. DAVID GILBERTSON, an individual, 

and MILLCREEK CHIROPRACTIC 

CLINIC,

Respondent.

No. 79927-4-I

DIVISION ONE

UNPUBLISHED OPINION

CHUN, J. — Dr. David Gilbertson provided chiropractic treatment for Arthur 

Soucy. After the treatment, Soucy suffered a stroke. He sued, alleging that 

Gilbertson performed a technique that caused dissection of his vertebral arteries, 

which in turn caused his stroke. At trial, Soucy requested a res ipsa loquitur jury 

instruction, which the trial court denied. The jury returned a verdict in 

Gilbertson’s favor. Soucy appeals. Because the trial court should have given a 

res ipsa loquitur instruction and its failure to do so prejudiced Soucy, we reverse 

and remand.

BACKGROUND

Soucy visited Gilbertson’s clinic to receive treatment for neck pain. 

Gilbertson had before provided treatment to Soucy for the pain, but the 

techniques he used had not relieved it. In the session at issue, Gilbertson twice 
No. 79927-4-I/2

2

performed an occipital lift on Soucy.

1

 It was the first time he had used this 

technique on Soucy. After each use of the technique, Soucy felt a tear in his 

neck. Soucy stood up and told Gilbertson he felt “woozy” and “weird.” Gilbertson 

performed another technique on Soucy. Soucy again told Gilbertson that he felt 

“woozy” and “weird.” Gilbertson told him to stay in the clinic for a few minutes. 

While walking to the waiting room, Soucy felt as if he had no control over his 

legs. After breaking out in a cold sweat and beginning to feel nauseated, Soucy 

walked to the restroom. He tried to vomit but could not. Soucy left the restroom 

to find Gilbertson’s assistant, who directed him back to Gilbertson’s office after 

he told her he was not feeling well. Soucy told Gilbertson he felt like he was 

having a stroke, and Gilbertson suspected the same. Gilbertson had his staff call 

911. 

A doctor diagnosed Soucy as having suffered a stroke. A later diagnosis 

revealed he had also suffered dissections in his vertebral arteries and 

fibromuscular dysplasia (FMD).2

Soucy sued Gilbertson, alleging the occipital lift caused his stroke. He

requested a res ipsa loquitur jury instruction, which the trial court denied. The 

jury returned a defense verdict.

 

1 The parties also call this manipulation a “Chrane condyle lift.” This technique is 

a high-velocity, low-amplitude maneuver intended to decompress the neck.

2 FMD is a connective tissue disorder that may predispose a person to 

developing arterial dissections.
No. 79927-4-I/3

3

ANALYSIS

Soucy argues the trial court erred in denying his request for a res ipsa 

loquitur instruction, and that this error prejudiced him. We agree.

When res ipsa loquitur applies, a plaintiff need not prove that the 

defendant committed any specific act of negligence. Pacheco v. Ames, 149 

Wn.2d 431, 436, 69 P.3d 324 (2003). The doctrine permits the jury to infer 

negligence “on the basis that the evidence of the cause of the injury is practically 

accessible to the defendant but inaccessible to the injured person.” Id. Res ipsa 

loquitur applies when: 

(1) the accident or occurrence producing the injury is of a kind which 

ordinarily does not happen in the absence of someone’s negligence, 

(2) the injuries are caused by an agency or instrumentality within the 

exclusive control of the defendant, and (3) the injury-causing 

accident or occurrence is not due to any voluntary action or 

contribution on the part of the plaintiff.

Jackass Mt. Ranch, Inc., v. S. Columbia Basin Irrig. Dist., 175 Wn. App. 374, 

398, 305 P.3d 1108 (2013) (quotation marks omitted) (quoting Horner v. N. Pac. 

Beneficial Ass’n Hosp., Inc., 62 Wn.2d 351, 359, 382 P.2 518 (1963)). A plaintiff 

may be entitled to a res ipsa loquitur instruction “even if the defendant’s 

testimony, if believed by the jury, would explain how the event causing injury to 

the plaintiff occurred.” Pacheco, 149 Wn.2d at 440. Indeed, “[e]ven where the 

defendant offers weighty, competent and exculpatory evidence in defense, the 

doctrine may apply.” Id.

Once, through use of res ipsa loquitur, the plaintiff establishes a prima 

facie case of negligence, “the defendant must then offer an explanation, if [they] 
No. 79927-4-I/4

4

can. ‘If then, after considering such explanation, on the whole case and on all 

the issues as to negligence, injury and damages, the evidence still 

preponderates in favor of the plaintiff, plaintiff is entitled to recover; otherwise 

not.’” Pacheco, 149 Wn.2d at 441–42 (internal quotation marks omitted) (quoting 

Covey v. Western Tank Lines, 36 Wn.2d 381, 392, 218 P.2d 322 (1950)).

“A party is entitled to a jury instruction only if it has offered substantial 

evidence to support the instruction.” Cooper v. Dep’t of Labor & Indus., 188 Wn. 

App. 641, 647–48, 352 P.3d 189 (2015). Evidence is substantial if it could 

“persuade a fair-minded person of the truth of a declared premise.” 

Nationscapital Mortg. Corp. v. Dep’t of Fin. Inst., 133 Wn. App. 723, 738, 137 

P.3d 78 (2006). In determining whether substantial evidence supports the 

instruction, we must view the evidence in the light most favorable to the 

instruction’s proponent. Mina v. Boise Cascade Corp., 37 Wn. App. 445, 448, 

681 P.2d 880 (1984), aff’d, 104 Wn.2d 696, 710 P.2d 184 (1985).

We review de novo a trial court’s decision on a jury instruction if based on

a matter of law, or for abuse of discretion if based on a matter of fact. 

Kappelman v. Lutz, 167 Wn.2d 1, 6, 217 P.3d 286 (2009). Whether res ipsa 

loquitur applies is a question of law. Pacheco, 149 Wn.2d at 436. And we will 

reverse a trial court’s error on jury instructions only if the error is prejudicial. 

Stiley v. Block, 130 Wn.2d 486, 498–99, 925 P.2d 194 (1996).
No. 79927-4-I/5

5

A. Res Ipsa Loquitur Instruction

1. Relationship between FMD and vertebral artery dissection

Gilbertson’s primary argument on all three elements of res ipsa loquitur is 

that vertebral artery dissections occur in persons, like Soucy, who have FMD in 

their vertebral arteries. Thus, he argues, the dissection and stroke are of a kind 

that ordinarily happen without negligence, the instrumentality causing the injury 

was not within Gilbertson’s exclusive control, and Soucy voluntarily contributed to 

his injuries.3 But interpreting the facts about FMD in the light most favorable to 

Soucy—as Mina requires—substantial evidence suggests he did not have FMD 

in his vertebral arteries at the time of the treatment at issue.

A defense expert testified at trial that spontaneous vertebral artery 

dissection and strokes can occur among people who have FMD. This defense 

expert also testified that Soucy had FMD in his vertebral arteries when the 

dissection occurred, but not in the segment of the vertebral arteries where the 

dissection occurred.

A plaintiff-side expert testified there was no evidence of FMD in Soucy’s 

vertebral arteries at any time.

Soucy’s treating physician found evidence of FMD in his renal arteries,4

 

3 The parties did not dispute that the arterial dissection led to the stroke.

4 A renal artery is “any of the branches of the abdominal aorta that supply the 

kidneys being in man one to each kidney, arising immediately below the origin of the 

superior mesenteric artery, dividing into four or five branches which enter the hilum of 

the kidney, and giving off smaller branches to the ureter, adrenal gland, and adjoining 

structures.” WEBSTER’S THIRD NEW INTERNATIONAL DICTIONARY 1921 (2002).
No. 79927-4-I/6

6

but not in the “precerebral vessels.”5 That physician stated that the FMD in 

Soucy’s renal arteries put him at risk for future dissections. Another treating 

physician stated that the contours of Soucy’s left vertebral artery—including at 

the time of treatment—were subtly irregular, “which may reflect underlying [FMD] 

though this is not clearly apparent on the angiogram.” Soucy’s medical record 

from the day of his stroke does not mention FMD. His record from the next day

notes FMD in his renal arteries.

Interpreting these facts in the light most favorable to Soucy, substantial 

evidence suggests he did not have FMD in his vertebral arteries at the time of 

treatment. And Gilbertson does not point to evidence suggesting that arterial 

dissections might occur in areas unaffected by FMD—indeed, his own expert’s 

testimony suggests that dissections are more likely to occur in areas affected by 

FMD. Because Soucy “is not required to ‘eliminate with certainty all other 

possible causes or inferences’ in order for res ipsa loquitur to apply,” he need not 

conclusively show that he did not have FMD in his vertebral arteries at the time of 

treatment. Pacheco, 149 Wn.2d at 440–41 (quoting Douglas v. Bussabarger, 73 

Wn.2d 476, 486, 438 P.2d 829 (1968)).6 We thus evaluate whether the trial court 

 

5 Neither the parties nor the medical records define “precerebral vessels,” but 

Soucy’s briefing implies—and his counsel stated at oral argument—that a vertebral 

artery is a precerebral vessel.

6

In support of his argument that res ipsa loquitur does not apply, Gilbertson cites 

Morner v. Union Pac. R.R. Co., 31 Wn.2d 282, 196 P.2d 744 (1948). In discussing 

whether res ipsa loquitur applied to a claim of negligence, Morner states that “‘[i]f it 

appears that two or more instrumentalities, only one of which was under defendant’s 

control, contributed to or may have contributed to the injury, the doctrine cannot be 

invoked.’” Id. at 296 (quoting 38 AM. JUR. 997 Negligence, § 300). But in deciding that 

the plaintiff was not entitled to a res ipsa loquitur instruction, the court reasoned that the 

instruction “imposed upon [the defendant] the unjust burden of producing evidence upon 

some unknown, uncertain, conjectural cause which neither party had, or could have had, 
No. 79927-4-I/7

7

should have given a res ipsa loquitur instruction assuming that Soucy did not 

have FMD in his vertebral arteries.

2. Was the occurrence causing Soucy’s injury of a kind that does not 

ordinarily happen in the absence of negligence?

This first element of res ipsa loquitur is satisfied when one of three 

conditions exist:

(1) When the act causing the injury is so palpably negligent that it 

may be inferred as a matter of law, i.e., leaving foreign objects, 

sponges, scissors, etc., in the body, or amputation of a wrong 

member; (2) when the general experience and observation of 

mankind teaches that the result would not be expected without 

negligence; and (3) when proof by experts in an esoteric field creates 

an inference that negligence caused the injuries.

Pacheco, 149 Wn.2d at 438–39 (internal quotation marks omitted) (quoting 

Zukowsky v. Brown, 79 Wn.2d 586, 595, 488 P.2d 269 (1971)).

Soucy argues that because proof by trial chiropractic experts supported an 

inference that negligence caused his injury, he has met the first element of res 

ipsa loquitur. As referenced above, Gilbertson counters that because Soucy 

suffers from FMD in his vertebral arteries, and vertebral artery dissections can 

occur in such persons, his injuries are of a kind that may ordinarily happen 

without negligence. We conclude that Soucy has satisfied this element through 

expert testimony.7

 

in mind.” Id. at 299. This aligns with the reasoning of later cases, such as Pacheco, 

which states that “res ipsa loquitur is inapplicable where there is evidence that is 

completely explanatory of how an accident occurred and no other inference is possible 

that the injury occurred another way.” 149 Wn.2d at 439–40; see also Kemalyan v. 

Henderson, 45 Wn.2d 693, 705, 277 P.2d 372 (1954). Because evidence conflicts as to

the extent of Soucy’s FMD, the evidence does not completely explain how the accident 

occurred, so res ipsa loquitur may apply.

7 Soucy argues in the alternative that general experience teaches that his injuries 

could not have occurred without negligence. Since we conclude Soucy has established 
No. 79927-4-I/8

8

In ZeBarth v. Swedish Hosp. Med. Cen., the plaintiff sued a hospital when 

he became paralyzed after receiving radiation treatment there. 81 Wn.2d 12, 13, 

499 P.2d 1 (1972). Our Supreme Court held that testimony by radiation therapy 

experts that paralysis does not ordinarily occur from radiation therapy in the 

absence of negligence constituted “testimony of experts in an esoteric field”

sufficient to satisfy the first element. ZeBarth, 81 Wn.2d at 22.

Here, at trial, Gilbertson agreed that an occipital lift, properly performed on 

a healthy person, cannot cause a tear in their vertebral arteries. Soucy’s 

chiropractic expert testified that a properly performed occipital lift should not 

cause a vertebral artery dissection. Gilbertson’s chiropractic expert testified that 

an occipital lift could not cause vertebral artery dissection. But his testimony just 

before this statement appears to imply that it is a “properly administered” occipital 

lift that could not cause vertebral artery dissection.8 Interpreting all the above

 

res ipsa loquitur’s first element through expert testimony, we do not consider this 

argument.

8 The testimony provides: 

[Defense chiropractic expert]: What I found the most interesting about this 

particular study was that, number one, that a properly administered

chiropractic treatment, the high-velocity/low-amplitude, could not cause a 

vertebral artery dissection or disruption to that vertebral artery, but also 

simply range of motion and things like mobilization actually put more strain 

on the vertebral artery than did a chiropractic treatment.

[Defense counsel]: And this article made the conclusion, did it not, that 

under normal circumstances, a typical, high-velocity, low-amplitude spinal 

manipulative thrust is unlikely to disrupt the VA, the vertebral artery; 

correct?

[Defense chiropractic expert]: Correct.

[Defense counsel]: And it doesn’t say Chrane condyle lift, it doesn’t say 

diversified, it says high-velocity, low-amplitude. Is that what the Chrane 

condyle is?

[Defense chiropractic expert]: Yes, it is.

(Emphasis added).
No. 79927-4-I/9

9

testimony in the light most favorable to Soucy, performing an occipital lift on a 

healthy person does not ordinarily cause vertebral artery dissection absent 

negligence. And assuming Soucy had no FMD in his vertebral arteries, this 

testimony supports an inference that Gilbertson improperly performed the 

occipital lift, leading to dissection of Soucy’s vertebral arteries. Substantial 

evidence supports res ipsa loquitur’s first element. 

3. Was the injury caused by something within the Gilbertson’s exclusive 

control?

Soucy argues he has met this element since Gilbertson had exclusive 

control over the occipital lift. We agree. 

Gilbertson again cites Morner v. Union Pac. R.R. Co. for the proposition 

that “if it appears that two or more instrumentalities, only one of which was under 

defendant’s control, contributed to or may have contributed to the injury, the 

doctrine cannot be invoked.” 31 Wn.2d 282, 296, 196 P.2d 744 (1948) (quoting 

38 AM. JUR. 997 Negligence § 300). He argues that because Soucy’s FMD may 

have contributed to the injury and was outside his control, the injury was not 

caused by something within Gilbertson’s exclusive control. But again, later 

decisions hold that a trial court should not give a res ipsa loquitur instruction if a 

cause is completely explanatory of the plaintiff’s injuries. Pacheco, 149 Wn.2d at 

439–40. Given conflicting evidence about the extent of Soucy’s FMD, 

Gilbertson’s theory does not completely explain Soucy’s injuries.
No. 79927-4-I/10

10

Gilbertson had exclusive control over the occipital lift, which Soucy claims 

caused his injuries. Viewing the evidence in the light most favorable to Soucy, 

we conclude that substantial evidence supports this element.

4. Was the injury-causing occurrence not due to any voluntary action or 

contribution by Soucy?

Soucy argues he did not contribute to Gilbertson’s performance of the 

occipital lift. Gilbertson argues this element is not satisfied because Soucy’s 

FMD contributed to his dissection and stroke. 

Gilbertson argues that Soucy cannot meet this element because he had 

FMD in his vertebral arteries, which contributed to his dissection and stroke. But 

even assuming FMD in Soucy’s vertebral arteries, a plaintiff’s pre-existing 

condition does not negate satisfaction of this element. See Marshall v. W. Air 

Lines, Inc., 62 Wn. App. 251, 261, 813 P.2d 1269 (1991). And even if it could so 

negate, viewing the evidence in the light most favorable to Soucy, he did not 

have FMD in his vertebral arteries, so substantial evidence would support a 

conclusion of no contribution.

We thus conclude that substantial evidence supports all three elements of 

res ipsa loquitur. 

B. Prejudice

Soucy argues that the trial court’s failure to give a res ipsa loquitur

instruction prejudiced him. We agree.

If evidence supports a party’s proposed instruction, a trial court’s omission 

of that instruction “will be ‘reversible error where it prejudices a party.’” Millican v. 
No. 79927-4-I/11

11

N.A. Degerstrom, Inc., 177 Wn. App. 881, 901, 313 P.3d 1215, 1225 (2013)

(quoting Barrett v. Lucky Seven Saloon, Inc., 152 Wn.2d 259, 267, 96 P.3d 386 

(2004)). Jury instruction error “is prejudicial if it substantially affected the 

outcome of the case,” but not if it “is trivial, or formal, or merely academic, and 

was not prejudicial to the substantial rights of the party assigning it, and in no 

way affected the outcome of the case.” Magana v. Hyundai Motor Am., 123 Wn. 

App. 306, 316, 94 P.3d 987 (2004) (internal quotation marks omitted) (quoting 

State v. Townsend, 142 Wn.2d 838, 848, 15 P.3d 145 (2001)).

Had the trial court given a res ipsa loquitur instruction, the jury could have 

inferred that Gilbertson negligently performed the occipital lift. Then, Gilbertson 

would have still been allowed to offer his explanation that FMD caused Soucy’s 

injuries, not his performance of the occipital lift. The jury would then have 

decided whether the evidence favored Soucy or Gilbertson.

But without such an instruction, Soucy bore the burden of establishing that 

Gilbertson had performed the lift negligently, where no recording of its 

performance existed. Soucy’s chiropractic expert could not specifically testify 

about whether Gilbertson had performed the lift negligently.

9 Soucy did not see 

Gilbertson perform the manipulation. Soucy did testify that Gilbertson’s use of 

the technique was not “especially strong or violent” as compared to other 

techniques Gilbertson had used. But since Gilbertson had not performed the lift 

on Soucy before, Soucy could not testify about whether the force used differed 

 

9

[Question]: In fact, you can’t sit here and testify exactly how he did the condyle 

lift in this particular case; correct?

[Answer]: Correct.
No. 79927-4-I/12

12

from normal performance of the occipital lift technique. Nor could Soucy testify 

whether the rotation or technique used differed from normal performance of the 

lift.

Res ipsa loquitur may apply if, as here, “the evidence of the cause of the 

injury is practically accessible to the defendant but inaccessible to the injured 

person.” Pacheco, 149 Wn.2d at 436. Gilbertson argues these are not such 

circumstances because neither he nor Soucy was aware of Soucy’s FMD. But 

assuming that Soucy did not have FMD in his vertebral arteries, the question is 

whether Gilbertson exclusively has knowledge as to the nature of his 

performance of the occipital lift technique—and he does.

Because, without a res ipsa loquitur instruction, Soucy bore a greater 

burden of proof, and Soucy had no practical access to evidence of the cause of 

his injuries, the trial court’s failure to give the instruction substantially affected the 

outcome of the case.

We conclude that trial court’s error prejudiced Soucy, and thus reverse 

and remand.

WE CONCUR: