UNITED STATES DISTRICT COURT FOR THE DISTRICT OF NEW HAMPSHIRE

Carl Alexander Cohen,

v. Case No. 1:20-cv-00943-PB Opinion No.

Boston Scientific Corporation, et al.

MEMORANDUM AND ORDER

The plaintiff, Alex Cohen, underwent surgery for an enlarged prostate

that resulted in diffuse thermal burns to his bladder. He brought a products

liability action against the manufacturer of one of the medical devices used in

his surgery as well as the company that provided the device to the hospital.

The defendants have moved to exclude one of Cohen’s engineering experts

pursuant to Federal Rule of Evidence 702. For the foregoing reasons, the

defendants’ motions to exclude the expert’s testimony (Doc. 69 and Doc. 73)

are denied without prejudice.

I. BACKGROUND

A. The GreenLight XPS Laser System

Boston Scientific Corporation manufactures the GreenLight XPS Laser

System, a medical device used in various surgeries to vaporize and coagulate

tissues. Doc. 69-2 at 16. The device consists of two components: a console,

which generates a green laser light, and a fiber, which transmits the laser light from the console to the targeted tissue in a patient’s body.

The laser

light is absorbed by the red blood cells in the targeted tissue, which generates

heat and causes the cells to burst, thereby vaporizing the tissue. Id. at 17.

One type of surgery the GreenLight device can be used for is

photoselective vaporization of the prostate (PVP). Id. at 17, 24. This

procedure is used to treat benign prostatic hyperplasia (BPH), id., a condition

in which a patient’s prostate gland becomes enlarged and squeezes the

urethra, Doc. 82-11 at 4. During a PVP procedure, a laser technician operates

the console, turning it on and placing it on standby mode while the surgeon

prepares for surgery. Doc. 71-3 at 28-29. The surgeon has a bag of saline

solution connected to the laser fiber and adjusts the flow until she and the

laser technician are “happy with the drip rate.” Id. at 27. This saline “runs

through the fiber” throughout the surgery and aids with cooling the fiber. Id.

at 26. The fiber is then inserted into the surgeon’s resectoscope, a surgical

instrument that also includes a camera device as well as a tube for a second,

separate supply of saline solution. Id. at 24, 27; Doc. 71 at 4. The surgeon

inserts the resectoscope into the patient’s bladder via the urethra. Doc. 75 at

1. When she is ready to begin the procedure, she instructs the laser

technician to switch the device off standby mode. Doc. 71-3 at 28. At this

point, the surgeon controls the laser by using a foot switch, which includes

2 pedals to initiate coagulation, vaporization, or standby modes. Id.; Doc. 69-2

at 45.

Throughout the procedure, the surgeon uses the irrigation tube

attached to her resectoscope to “constantly” deliver saline fluid to the surgical

area, controlling the flow using a valve on the resectoscope. Doc. 71-3 at 23,

25. This irrigation helps the surgeon visualize the surgical field by moving

tissues out of the way and flushing away blood and other debris. Id. at 23.

The GreenLight device does not specify the temperature to which this

irrigation fluid should be heated, and surgeons have varying preferences,

electing to use saline heated to either room temperature (approximately 68°F

or 20°C) or just above physiological temperature (around 104°F or 40°C). See

id. at 19; Doc. 71-8 at 17. As the saline circulates through the patient’s

urinary system and is replaced by new irrigant, it is then drained out via a

catheter. Doc. 71-3 at 23; Doc. 75 at 2.

B. Cohen’s Surgery and the Aftermath

In 2016, Cohen saw Dr. Shilpa Lamba, M.D., a board-certified urologist

at Manchester Urology Associates in Dover, New Hampshire, complaining of

“lower urinary tract symptoms.” Doc. 71-3 at 5-7. She diagnosed him with

BPH and, after a year of trying various medications to no avail,

recommended surgical intervention. Id. at 7-8. She presented Cohen with two

options: PVP or transurethral resection of the prostate (TURP). Id. at 8-9. In

3 contrast to PVP, which uses the GreenLight device to vaporize tissue, TURP

uses a surgical instrument containing electrodes—either a monopolar loop or

a bipolar loop—to resect unwanted tissue. Doc. 69 at 3; Doc. 82-2 at 88.

Cohen elected PVP, and Dr. Lamba performed the procedure in July

2017, at Wentworth-Douglass Hospital in Dover, New Hampshire. Doc. 11 at

10; Doc. 75 at 2. She used the GreenLight device and irrigation saline

solution heated to approximately 103 or 104°F, Doc. 71-3 at 19; Doc. 71-5 at

6, to vaporize several sections of enlarged prostate tissue, Doc. 75 at 3. The

surgery proceeded as normal until Dr. Lamba encountered an eight-to-ten-

millimeter nodule at the apex of the prostate that would not vaporize. Doc. 75

at 3. In her attempt to remove this nodule, she “passed the laser fiber

between the nodule and the capsular wall and initiated laser vaporization,”

but the metal cap at the end of the fiber broke off. Id. At this point, one of the

device’s “automatic safety mechanism[s]” activated, and the device switched

back to standby mode. 1 Doc. 71-3 at 29. Dr. Lamba was able to safely retrieve

the fiber’s cap from Cohen’s body but decided to abandon the PVP procedure,

1 This mechanism, known as FiberLife, “continuously monitors the temperature of the tip of the fiber and momentarily stops the laser emission when the fiber gets too hot.” Doc. 69-2 at 16. It is activated if “tissue or vapor bubbles accumulate on the tip [of the fiber], or if for other reasons there is damage due to excessive heating of the fiber.” Id. In “most cases,” the laser will “turn back on immediately and the procedure continues without interruption”; but if FiberLife is “activated continuously,” the console “will automatically detect this condition, [and] put the laser in Standby mode.” Id.

4 switching to the TURP technique and successfully excising the nodule using a

bipolar loop. Doc. 75 at 3.

Towards the end of the surgery, Dr. Lamba inspected the surgical area

for bleeding and evidence of laser vaporization, which has an immediate,

visible effect on the tissue. Id.; Doc. 71 at 5. She documented in her surgical

notes that the ureteral orifices were “away from any vaporization or

resection.” Doc. 75 at 3. She then removed her resectoscope and irrigated the

bladder. Id. All in all, she recorded that Cohen “tolerated the procedure well

with no complications.” Id.

But at a follow-up appointment with Dr. Lamba a few days later,

Cohen reported feeling nauseous and feverish as well as having abdominal

pain. Doc. 11 at 10; Doc. 71-3 at 11-12. Concerned he wasn’t convalescing as

she “would expect after [the] procedure,” Dr. Lamba ordered several tests,

including bloodwork and an ultrasound of the kidneys and bladder. Doc. 71-3

at 12. But before the ultrasound could be conducted, Cohen presented to the

emergency department with persistent symptoms, including “complete[]

incontinen[ce].” Doc. 11 at 10; Doc. 71-3 at 13. He was diagnosed with

hydronephrosis, “a dilation of the collecting system where the urine collects

in the kidneys,” and a urinoma, suggesting “some leakage of urine.” Doc. 71-3

at 13-14. Soon thereafter, Dr. Lamba installed a stent in Cohen’s right ureter

to aid the kidney’s drainage. Id. at 14-15.

5 Cohen continued to experience incontinence in the months following

the surgery. Doc. 75-1 at 2. In October 2017, Dr. Lamba’s colleague, Dr.

Cormac O’Neill, M.D., performed a cystoscopy to examine Cohen’s urinary

system. Id. He could not locate the ureteral orifices, and he observed thermal

injuries throughout the bladder area. Id. at 2-3 (documenting “significant

thermal effect in the prostatic fossa” and “significant exudative changes

consistent with a thermal injury to the bladder”). He subsequently diagnosed

Cohen with “[s]evere thermal cystitis.” Id. at 2. Consequently, Cohen

underwent extensive reconstructive surgery, has a permanent urostomy bag,

and is in constant pain. Doc. 11 at 2, 11. He is also permanently incontinent

and impotent. Id.

C. Cohen’s Lawsuit and Dr. Jarrell’s Opinions

Cohen filed suit in state court in July 2020, and the case was removed

to this court on diversity grounds. Doc. 1. He alleges that the GreenLight

device has design and warning defects and has sued Boston Scientific for

strict products liability, breach of the implied warranty of merchantability,

and violation of New Hampshire’s Consumer Protect Act (CPA). Doc. 11 at

11-22. He also brings products liability and breach of the implied warranty of

merchantability claims against Republic Surgical, the company that provided

6 the GreenLight console to the hospital for use during Cohen’s surgery. 2 Id. at

25-39.

Cohen has identified several experts whose testimony he plans to rely

on at trial. One such expert, Dr. John Jarrell, Ph.D., is a licensed mechanical

engineer with advanced degrees from Brown University and nearly thirty

years of experience analyzing product designs, manufacturing processes, and

materials selections and failures, often in cases involving medical devices and

drug delivery systems. Doc. 82-3 at 3-4. As part of his analysis in this case,

Dr. Jarrell inspected the GreenLight console and an exemplar fiber, reviewed

the device’s directions for use, and surveyed public reports of adverse events,

including recall data and complaints filed with the U.S. Food and Drug

Administration (FDA). Id. at 11, 18-22.

Dr. Jarrell also performed a series of calculations to determine “the

raise [sic] in saline irrigation temperature in response to the energy output”

of the GreenLight device, which he provided in an initial report. Id. at 23.

Noting that the vaporization process “absorbs some of the energy produced

by” the laser and thus affects the amount of energy available to heat the

2 Cohen also originally asserted claims for negligence, breach of an express warranty, and breach of the implied warranty of fitness for a particular purpose against Boston Scientific and Republic Surgical. Doc. 11 at 14-22, 28-37. However, those claims have since been abandoned. Doc. 82 at 41-42; Doc. 98 at 147; see Doc. 81 at 4. Cohen has also abandoned his CPA claim against Republic Surgical. See Doc. 81 at 4.

7 saline, he performed two sets of calculations—one under vaporizing

conditions and one under non-vaporizing conditions. 3 Id. at 6, 23-26.

Simulating the period of failed vaporization of the nodule during

Cohen’s surgery, Dr. Jarrell calculated the temperature increase of the saline

using the following formula:

Q c= m ∗ ∆T

where c is the specific heat capacity of saline in Joules per kilogram degree

Kelvin (J/kgK), Q is the device’s energy output in Joules (J), m is the mass of

the irrigation saline in kilograms (kg), and ∆T is the change in temperature of

the irrigation saline in degrees Kelvin (K). Id. at 23. Relying on known

constants and data from the laser’s specifications and Cohen’s surgery, Dr.

Jarrell then solved for ∆T.

The specific heat capacity of saline is a known constant, 4,185 J/kgK.

Id. The maximum power of the device is 180 watts (W), or 648,000 J over the

course of one hour. Id.; Doc. 82-2 at 110. Then, knowing, based on the medical

records for Cohen’s surgery, that 18 liters (L) of irrigation saline were

3 The defendants’ arguments to exclude Dr. Jarrell’s testimony do not challenge Dr. Jarrell’s calculations under vaporizing conditions. Therefore, in the interest of brevity, the details of those calculations are not reproduced here. Those calculations concluded that, during periods of vaporization when the GreenLight device was operating at “maximum theoretical energy production and cutting,” the highest temperature the saline would likely reach is between 116.6°F (47°C) and 119.5°F (48.6°C). Id. at 25.

8 administered over the course of the approximately 100-minute-long surgery,

Dr. Jarrell determined that the flow rate of the saline was 10.8 L/hour, or

about 10.8 kg over the course of one hour. Doc. 82-2 at 110. Assuming that

“all the laser energy was converted to heat” and excluding “heat flow out of

the bladder,” he calculated the increase in temperature of the saline resulting

from the use of the laser to be about 25.83°F (14.35° C). Doc. 82-3 at 23.

Thus, in a procedure like Cohen’s, where the surgeon used irrigation

saline preheated to just above physiological temperatures (104°F or 40°C),

Dr. Jarrell opined that the laser could increase the temperature of the

incoming irrigation saline to around 129.83°F (54.35°C). Id. at 23. He then

noted that, according to the scientific literature, human skin takes

“approximately 1.5 minutes” to burn at 127.4°F (53°C) and “approximately 30

seconds” at 131°F (55°C). Id.

Dr. Jarrell also recognized, however, that “according to published

scientific literature dealing with the elevated temperature of bladder

irrigants, the temperature of the incoming irrigation saline is expected to

drop 2 to 2.5°C in the process of reaching the bladder.” Id. Accordingly, he

decreased his calculations by that same amount, thus concluding that the

irrigation saline would likely only be heated to between 125.33°F (51.85°C)

and 126.23°F (52.35°C). Id. He then noted that, according to the scientific

9 literature, human skin takes “approximately 4 minutes” to burn at 123.8°F

(51°C). Id.

Dr. Jarrell produced a supplemental report several months later that

responded to opinions proffered by the defendants’ experts. Doc. 82-4. In this

report, he noted that it “is well known that the saline water has relatively

minimal direct absorption of the laser,” and tissues “are nearly 1 million

times more absorpti[ve] of laser compared to the saline.” Id. at 4. Therefore,

he stated that it was “always [his] opinion that the laser energy was absorbed

by the tissues, which then heated up the surrounding [saline].” Id.

As things now stand, Dr. Jarrell proffers several opinions. First, he

explains that the GreenLight device is defective because its “power output

capacity . . . can cause transient increases in the temperature” of the

irrigation saline to levels that “can cause burns.” Doc. 82-3 at 6. Second, he

states that Cohen’s injuries were “most likely due to” this defect. Id. Third, he

notes that alternative technologies—such as using a similar laser in

combination with a thermocouple or temperature-sensing catheter—were

available to “monitor the temperature of the saline fluid” and “alert[] the

surgical personnel of unsafe temperatures within the bladder.” Id. at 7-8. And

fourth, he opines that Boston Scientific “failed to adequately warn or specify

the temperature to be used for the irrigation saline.” Id. at 7.

10 Boston Scientific has moved to entirely exclude Dr. Jarrell’s testimony,

arguing that his opinions do not meet the admissibility standards set forth in

Federal Rule of Evidence 702. Doc. 69. Republic Surgical has joined this

motion. Doc. 73. Additionally, both defendants have filed motions for

summary judgment, contending, among other things, that without Dr.

Jarrell’s testimony, the essential elements of Cohen’s claims cannot be

sufficiently proved. Doc. 71; Doc. 72.

II. STANDARD OF REVIEW

Federal Rule of Evidence 702 governs the admissibility of expert

opinion testimony. It provides:

A witness who is qualified as an expert by knowledge, skill, experience, training, or education may testify in the form of an opinion or otherwise if the proponent demonstrates to the court that it is more likely than not that: (a) the expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue; (b) the testimony is based on sufficient facts or data; (c) the testimony is the product of reliable principles and methods; and (d) the expert’s opinion reflects a reliable application of the principles and methods to the facts of the case.

Fed. R. Evid. 702 (amended 2023). 4

4 This language reflects a set of recent amendments, which became effective on December 1, 2023. As explained in the commentary, these amendments do not “impose[] any new, specific procedures”; rather, they were “simply intended to clarify” that the preponderance of the evidence standard that governs the admissibility of other evidence under Federal Rule

11 Rule 702 charges the trial court with “ensuring that an expert’s

testimony both rests on a reliable foundation and is relevant to the task at

hand” before admitting it into evidence. Daubert v. Merrell Dow Pharm., Inc.,

(1993). “These two requirements—a reliable foundation

and an adequate fit—are separate and distinct.” Samaan v. St. Joseph Hosp.,

(1st Cir. 2012). The reliability prong asks whether “the

expert’s conclusion has been arrived at in a scientifically sound and

methodologically reliable fashion,” Ruiz-Troche v. Pepsi Cola of P.R. Bottling

Co.,

(1st Cir. 1998), while the “fit” prong asks whether the

expert’s conclusions have a “valid scientific connection to the pertinent

inquiry,” Lawes v. CSA Architects & Eng’rs LLP,

(1st Cir.

2020) (quoting Daubert v. Merrell Dow Pharm. Inc.,

, 1320 (9th

Cir. 1995)).

In analyzing the reliability of an expert’s opinion, a court should

generally focus on the expert’s “principles and methodology, not on the

conclusions that they generate.” Daubert,

; accord Samaan,

(explaining that the reliability analysis “necessitates an

inquiry into the methodology and the basis for an expert’s opinion”). “But

conclusions and methodology are not entirely distinct from one another,” and

of Evidence 104(a) also “applies to expert opinions under Rule 702.” Fed. R. Evid. 702 advisory committee’s note to 2023 amendment.

12 a court may “conclude that there is simply too great an analytical gap

between the data and the opinion proffered.” Gen. Elec. Co. v. Joiner,

(1997).

Nonetheless, “the trial court’s role as gatekeeper is not intended to

serve as a replacement for the adversary system.” Fed. R. Evid. 702 advisory

committee’s note to 2000 Amendment (quoting United States v. 14.38 Acres

of Land,

(5th Cir. 1996)). Instead, “[s]o long as an expert’s

scientific testimony rests upon ‘“good grounds,” based on what is known,’” it

should be admitted and “tested by the adversarial process.” Milward v. Acuity

Specialty Prods. Grp., Inc.,

, 15 (1st Cir. 2011) (quoting Daubert,

) (explaining that “[v]igorous cross-examination, presentation

of contrary evidence, and careful instruction on the burden of proof are the

traditional and appropriate means of attacking shaky but admissible

evidence”). Thus, the court must differentiate between “what is unreliable

support and what a trier of fact may conclude is insufficient support for an

expert’s conclusion.”

(emphasis in original). And in doing so, the court “is

not bound by the rules of evidence except those with respect to privileges.”

Daubert,

n.10 (quoting an earlier version of Fed. R. Evid.

104(a)).

“The party seeking to introduce the evidence has the burden of

establishing both its reliability and its relevance.” López-Ramírez v. Toledo-

13 González,

, 94 (1st Cir. 2022) (quoting Milward v. Rust-Oleum

Corp.,

(1st Cir. 2016)). So long as an expert opinion

satisfies the prerequisites set forth in Rule 702 by a preponderance of the

evidence, any questions as to credibility and weight must be reserved for the

jury.

III. ANALYSIS

The defendants attack Dr. Jarrell’s opinion testimony on several

grounds. First, they assert that he is unqualified to provide any of his

proffered opinions as to the GreenLight device. Doc. 69 at 5-6, 11-12, 15-16.

Second, they argue that his methodology is unreliable because he failed to

test his calculations, conduct a proper risk-benefit analysis, or adequately

consider alternative causes of Cohen’s injuries. Id. at 7-8, 10-11, 13-15. And

third, they argue that the application of his methodology is “demonstrably

flawed” because his calculations rest on incorrect assumptions, and his

conclusions do not comport with real-life data. Id. at 8-9, 11. I address each

set of arguments in turn.

A. Qualifications

1. Lack of Experience with Lasers

The defendants first argue that Dr. Jarrell is not qualified to opine as

to any potential defect in the GreenLight device or the adequacy of its

warnings because he has insufficient experience with laser systems and their

14 associated warnings. Id. at 3-6, 15-16. Cohen objects, arguing that Dr. Jarrell

has sufficient experience with laser systems and that, regardless, his

engineering background renders him qualified to provide his opinions. Doc.

82 at 7-12, 24-25. I agree with Cohen.

“[T]he general rule [is] that a court should consider all relevant

qualifications when ruling on the admissibility of expert testimony.” DaSilva

v. Am. Brands, Inc.,

, 361 (1st Cir. 1988). Consequently, a “lack

of personal experience . . . should not ordinarily disqualify an expert, so long

as the expert is qualified based on some other factor provided by Rule 702:

‘knowledge, skill, experience, training, or education.’” U.S. v. Liu,

(5th Cir. 2013) (emphasis in original). Thus, courts often decline to

“strictly confine[]” an expert to his “area of practice,” and instead allow him to

“testify concerning related applications.”

at 168-69 (quoting Wheeler v.

John Deere Co.,

(10th Cir. 1991)).

Many courts, moreover, including the First Circuit, have specifically

held that engineers are not required to have “experience with the specific

machine in question.” DaSilva, 845 F.2d at 361; see also DayCab Co., Inc. v.

Prairie Tech., LLC,

(6th Cir. 2023) (affirming the

admissibility of an engineer’s testimony based on his “extensive experience in

the fields of design, product development, manufacture and servicing of

machines,” despite his lack of “specific experience in fiberglass

15 manufacturing, conversion kits, or truck body work”); Anderson v. Raymond

Corp.,

(7th Cir. 2023) (noting that arguments attacking a

mechanical engineer’s lack of prior experience analyzing forklift accidents

were “misplaced” when he had “spent most of his professional career

investigating machine accidents and performing accident reconstructions”).

Instead, courts consider an expert’s “full range of practical experience as well

as academic or technical training.” Anderson,

(quoting United

States v. Parra,

(7th Cir. 2005)).

Here, Dr. Jarrell is qualified to offer opinions both as to the GreenLight

device’s capacity to overheat the irrigation saline to dangerous temperatures

and the availability of alternative designs. After inspecting the GreenLight

device and reviewing its specifications, Dr. Jarrell applied general principles

of physics—for example, the conversion of light energy to thermal energy, the

transfer of that energy to various materials, and the subsequent changes in

temperature of those materials—to perform a series of calculations to

determine the potential increase in the temperature of the saline when it is

brought into contact with energized prostate tissue. These concepts clearly

fall within his area of expertise. He has bachelor’s and master’s degrees in

Materials Science and Engineering, a doctorate degree in Biology, Medical

Science, and Engineering, and nearly thirty years of experience as a licensed

mechanical engineer, analyzing a variety of product materials, designs, and

16 failures. Doc. 82-3 at 3-4. Thus, even without any prior experience with the

GreenLight device, his general engineering qualifications are sufficient to

support his opinion testimony. See Chapman ex rel. Estate of Chapman v.

Bernard’s Inc.,

(D. Mass. 2001) (allowing a civil

engineer to opine on the structure and design of a daybed without any prior

furniture-related experience because his opinion primarily relied on “basic

principles of physics and engineering,” such as “the interaction of metal

tubes, bolts, springs and various stresses thereon”).

Dr. Jarrell is also qualified to opine on the adequacy of the GreenLight

device’s warnings for similar reasons. In forming his opinion on this matter,

Dr. Jarrell relied on his extensive experience in developing and evaluating

medical devices and their accompanying instructions and warnings. He has

performed failure analyses for various medical devices, which included

reviewing product data from the FDA and reviewing the accompanying

instructions and warnings. The fact that he admitted to never having worked

on warnings for a medical laser system is not dispositive.

While Dr. Jarrell’s lack of experience with similar lasers may impact

the weight a jury ultimately assigns to his opinion, it does not render his

opinion inadmissible in light of his academic credentials and other relevant

experience. Anderson,

(noting that “[a]n expert’s

17 specialization or lack thereof typically goes to the weight to be placed on her

opinion, not its admissibility”) (cleaned up).

2. Lack of Medical Expertise

The defendants next argue that Dr. Jarrell is unqualified to testify as

to the most likely cause of Cohen’s injuries because he is not a medical doctor.

This argument is a nonstarter because Cohen does not propose to elicit

medical opinions from Dr. Jarrell.

Dr. Jarrell appropriately relied on medical evidence in the record as to

what happened during Cohen’s surgery. He also appropriately relied on

medical evidence in the record to support Cohen’s contention that he suffered

diffuse thermal injuries to his bladder during surgery. Finally, he reasonably

relied on data from the medical literature to support his statements

concerning the temperature of and time of exposure to heated irrigation

saline that would be required to burn human tissue. Accordingly, all of the

opinions Dr. Jarrell proposes to express regarding the cause of Cohen’s

injuries are engineering opinions that he is qualified to offer. The fact that he

is not a medical doctor is irrelevant.

B. Unreliable Methodology

1. Lack of Testing

The defendants next fault Dr. Jarrell for failing to conduct his own

tests with the GreenLight device to confirm that his mathematical

18 calculations are “accurate, applicable to the real world, or meaningful.” Doc.

69 at 7. This, they argue, renders his methodology unreliable. Cohen

responds that testing is not a requirement for admissibility. Doc. 82 at 14-16.

I agree with Cohen.

Testing is, of course, “one of the most common and useful reliability

guideposts” when analyzing the admissibility of expert testimony. Lapsley v.

Xtek, Inc.,

(7th Cir. 2012). However, as the defendants

themselves note, courts have routinely held that testing is not a requirement

for admissibility. See, e.g., Quilez-Velar v. Ox Bodies, Inc.,

(1st Cir. 2016) (noting that there are “alternate methods of testing from

which the jury could evaluated reliability” besides physically testing a

design); Gussack Realty Co. v. Xerox Corp.,

(2d Cir. 2000)

(stating that an “expert need not have conducted her own tests”). Instead, the

Rule 702 analysis hinges on whether the expert’s “methodology . . . has been

adequately tested and accepted within the scientific community, not whether

his result has been evaluated.” Jenks v. N.H. Motor Speedway,

,

, at *3 (D.N.H. Feb. 8, 2012) (emphasis in original). And

here, Dr. Jarrell’s methodology passes muster.

Dr. Jarrell examined the GreenLight device, reviewed its specifications,

and then used this information along with commonly accepted scientific

principles—namely the laws of thermodynamics and an equation for specific

19 heat capacity—to perform a series of calculations. This use of generally

accepted principles of physics is sufficient to bridge the analytical gap

between his initial hypothesis and his final opinion. Cf. Lapsley,

(holding that simulations and mathematical or computer models are

“perfectly acceptable form[s] of test[s]”); Bodner v. Thunderbird Prods. Corp.,

No. 22-11179,

, at *1, *3 (11th Cir. Feb. 9, 2023) (upholding

the exclusion of an expert’s opinion where he failed to “perform any testing or

provide any calculations to support his opinions”). In short, as the Seventh

Circuit has put it, “[w]e do not require experts to drop a proverbial apple each

time they wish to use Newton’s gravitational constant in an equation.”

Lapsley,

.

Of course, a lack of testing can affect the weight a jury assigns to the

expert’s testimony, Williams v. Syphan, No. 22-3222,

, at *6

(6th Cir. Jan. 31, 2023), and the defendants are free to raise Dr. Jarrell’s lack

of testing or challenge any aspect of his calculations at trial. However, his

lack of testing does not constitute sufficient grounds to hold Dr. Jarrell’s

opinion inadmissible.

2. Failure to Perform a Risk-Utility Analysis

The defendants next argue that Dr. Jarrell’s methodology is unreliable

because he did not consider the GreenLight device’s “benefits or utilities”

when forming his opinions. Doc. 69 at 10-11. New Hampshire law requires a

20 jury to engage in risk-utility analysis when determining whether an allegedly

defective product is unreasonably dangerous. Price v. BIC Corp.,

(1997); see also Buckingham v. R.J. Reynolds Tobacco Co.,

(1998) (explaining that a product liability claim must allege that

a product is “defective” and “unreasonably dangerous” as separate elements).

But the defendants do not claim that Dr. Jarrell proposes to offer opinion

testimony that the GreenLight device is unreasonably dangerous as designed.

Accordingly, his failure to assess the GreenLight device’s costs and benefits

does not provide a basis for excluding his testimony.

3. Insufficient Consideration of Alternative Causes

Lastly, the defendants argue that Dr. Jarrell’s methodology is

unreliable because he failed to rule out what they claim are two alternative

causes of Cohen’s injuries: the possibility that Cohen’s burns could have been

caused by the improper use of a surgical blanket heater set to around 140°F

to heat the irrigation saline prior to Cohen’s surgery, or the possibility that

the saline became overheated during the use of the TURP procedure. 5

5 The defendants’ blanket warmer theory appears to be based primarily on a statement from Dr. Lambda that, at some time after Cohen’s procedure, she witnessed an unidentified person "removing irrigation fluid from the [surgical] blanket warmer, which is set to 140 degrees.” Doc. 71-3 at 35-36. However, Dr. Lamba also testified that she “ha[d] no evidence of that occurring at the time” of Cohen’s procedure. Id. at 37. The record, likewise, does not contain any evidence that supports this having happened during Cohen's procedure. To the contrary, there is evidence in the record that the

21 Among the things that a court should consider when evaluating

proposed expert testimony is whether the expert has “adequately accounted

for obvious alternative explanations.” Packgen v. Berry Plastics Corp.,

(1st Cir. 2017) (quoting Fed. R. Evid. 702 advisory committee’s

note to 2000 amendment). An expert, however, is “not required to eliminate

every other possible cause” for his opinion to be admissible. Id.; see also

Guinn v. AstraZeneca Pharms. LP,

(11th Cir. 2010) (per

curiam). Here, Dr. Jarrell has adequately considered obvious alternative

causes for Cohen’s injuries.

With respect to the defendants’ blanket warmer theory, Dr. Jarrell

reasonably concluded that it was an “unlikely” explanation for Cohen’s

injuries because he had seen no testimony or other evidence that the blanket

warmer had been used in Cohen’s surgery to heat the irrigation fluid. Doc.

82-2 at 139-40 (Dr. Jarrell explaining that the medical records indicate that

the irrigation fluid used in Cohen’s surgery had been heated to 104°F and

that the nurse who coordinated the surgeries testified that the irrigation fluid

had been placed in the correct warmer set to 104°F).

coordinating nurse “never put any bags [of irrigation fluid]” in the blanket warmer and that he palpated the bags to make sure they were not too warm for use. Doc. 83-10 at 3-4.

22 Dr. Jarrell also reasonably testified that, based on his research, the

only way the TURP procedure could result in diffuse thermal burns, such as

Cohen’s, was if a monopolar loop was used with a conductive irrigation fluid,

like saline; however, he explained that Cohen’s procedure used a bipolar loop,

and thus, TURP was an unlikely cause of Cohen’s injuries. Id. at 88-89.

Additionally, he noted that there is “no evidence in the medical records of any

problems with the TURP device,” while there was “evidence of overheating of

the Greenlight device.” Id. at 240.

The fact that Dr. Jarrell may not have completely eliminated these

other possible causes does not undermine “the soundness of the

methodology.” Ambrosini v. Labarraque,

(D.C. Cir. 1996)

(quoting Mendes-Silva v. United States,

(D.C. Cir.

1993)). Whether his causation opinions are persuasive given the defendants’

theories as to other possible causes is ultimately a question for the jury.

C. Application of Methods

1. Incorrect Assumption Regarding Conductivity

The defendants also complain that Dr. Jarrell should not be permitted

to testify that the GreenLight device caused the irrigation fluid to overheat

and burn Cohen’s bladder because his opinion is based on an unwarranted

assumption that “all the laser energy was converted to heat” when the laser

was applied to Cohen’s non-vaporized prostate nodule and all of that heat

23 was “transferred from the non-vaporized tissue to the saline.” Doc. 69 at 8. In

support of their argument, they cite their own expert, Dr. Erwin Lau, Ph.D.,

who opined that “[s]uch 100% transfer of energy is fundamentally impossible”

because “the laser-heated tissue can transfer only a fraction . . . of its

absorbed laser energy to heat the saline.”

(quoting Doc. 69-8 at 24).

Dr. Jarrell opined that when the GreenLight device emits laser light

under non-vaporizing conditions, the targeted tissue absorbs the light energy

and converts it to thermal energy, or heat. That heat is then transferred to

the irrigation saline as it flows through the urinary system, and results in an

increase in the temperature of the saline. In calculating this temperature

Q change, Dr. Jarrell relied on the formula, c = . This equation is clearly a m ∗ ∆T

generally accepted formula employed by the scientific community, and Dr.

Lau does not contest its relevance to the calculations at hand.

As Dr. Lau points out, however, Dr. Jarrell’s use of this formula

appears to implicitly assume perfect conductivity between the nodule and the

irrigation saline that comes into contact with the nodule, such that the non-

vaporized nodule transfers 100% of the energy introduced into it by the laser

to the irrigation saline. If this assumption is correct, or at least reasonable,

then the aforementioned formula may very well be sufficient, and Dr.

Jarrell’s calculations may be sufficiently reliable to be admissible.

24 But Dr. Jarrell does not address this assumption in his reports or

deposition testimony, and Cohen’s briefing fails to adequately explain why

this assumption is reasonable. On the other hand, the defendants also fail to

sufficiently explain why Dr. Jarrell’s apparent assumption is unreasonable.

Dr. Lau’s report indicates that “[c]orrect calculations of saline temperature

would require accounting for heat capacities, thermal conductivities, and

heat exchange rates between multiple bodies (tissue, flowing saline,

surrounding tissue, fiber tip, etc.) that Dr. Jarrell did not perform.” Doc. 69-8

at 25. Yet he does not explain how Dr. Jarrell’s failure to account for these

variables undermines his analysis. I am, of course, mindful of the fact that

the burden is on the proponent of expert testimony to prove that it is

admissible. But I am simply unable to reliably resolve the defendants’

challenge to this aspect of Dr. Jarrell’s proposed testimony without receiving

additional evidence. Accordingly, I will need to hold an evidentiary hearing

before I can determine whether Dr. Jarrell’s testimony on causation is

admissible.

2. Incorrect Adjustment for Cooling

The defendants also challenge the adjustment Dr. Jarrell made to

account for the outflow of saline throughout the procedure, which they note

“would mitigate any theoretical heat transfer.” Doc. 69 at 9. Specifically, they

argue that the 2 to 2.5°C adjustment Dr. Jarrell made is insufficiently

25 supported because the scientific paper from which it was obtained describes

the drop in temperature of a solution as it flows into the bladder, not the

cooling experienced as the solution flows out of the bladder.

Cohen does

not specifically address this argument, but regardless, I find it unpersuasive.

As an initial matter, Dr. Jarrell’s report indicates that “the

temperature of the incoming saline is expected to drop 2 to 2.5°C in the

process of reaching the bladder,” Doc. 82-3 at 23, so it is not clear that his

reliance on this value from the literature is inapposite. But, to the extent the

defendants disagree on the specific value used, such a discrepancy is simply a

“battle of the experts,” and the defendants do not explain why such an error

is so egregious as to make his testimony inadmissible.

Alternatively, to the extent the defendants contend that Dr. Jarrell did

not sufficiently account for the dissipation of heat as heated saline flowed out

of the bladder and was replaced with cooler saline, it is unclear whether such

an adjustment is necessary. As Dr. Jarrell noted in his report, and as Cohen

explained at the hearing on the present motions, the volume of Cohen’s

bladder was substantially restricted due to his enlarged prostate, reducing its

capacity from the typical 500 milliliters to between 142 and 177 milliliters.

Doc. 82-3 at 7. Given this smaller volume, Dr. Jarrell opined that Cohen’s

bladder “would hold less of the cooler temperature irrigant then a normal size

bladder.”

And assuming this restricted bladder size and an irrigation flow

26 rate of 10.8 L/hour, the irrigation fluid in Cohen’s bladder could be completely

replaced very quickly, thereby reducing the dissipation of heat by cooler

irrigant. Defendants do not sufficiently develop this argument, and therefore

I decline to consider it further.

3. Warnings

The defendants argue that Dr. Jarrell’s opinion regarding the

inadequacy of the GreenLight device’s warnings is “baseless speculation”

because Dr. Lamba admitted to not having read the device’s manual or

instructions, thereby rendering any such warning futile. Doc. 69 at 16. First,

in so arguing, the defendants misapprehend Dr. Jarrell’s opinion on this

issue. Dr. Jarrell explained in his deposition that “the [directions for use] and

the manual [are] not the only places where warnings are applied in these

types of circumstances.” Doc. 82-2 at 80. Instead, he explained,

manufacturers can provide warnings via “a placard, a sticker on the

machine,” “[w]arnings applied directly to consoles,” a note on a “digital

screen,” a check box, or updated training events or literature. Id. at 81-83.

But more importantly, this is an argument for judgment as a matter of law

on the warning claim, not an argument for excluding an expert’s opinion

under Rule 702. The defendants fault Dr. Jarrell for providing insufficient

causation testimony when his opinion goes to the GreenLight device’s defect,

not causation. And an expert is not required to establish every element of a

27 claim to be admissible. In re Ethicon, Inc. Pelvic Repair Sys. Prod. Liab.

Litig., No. 2327,

, at *2-3 (S.D.W. Va. Aug. 30, 2016) (“A

single expert need not provide all the pieces of the puzzle for their testimony

to be useful to the jury in determining the ultimate issues in the case.”).

Thus, Dr. Jarrell does not need to show that a warning would have been seen

or heeded in order for his opinion to be admissible.

4. Lack of Corroborating Data

Lastly, the defendants argue that Dr. Jarrell’s opinions should be

excluded because they are not supported by “real-world data.” Doc. 69 at 11.

They explain that during his deposition, Dr. Jarrell could neither identify any

literature documenting similar cases of thermal injuries caused by the

GreenLight device nor name a urologist who agreed with his opinion.

But

the defendants’ argument is unpersuasive. As Cohen correctly points out,

showing that a particular defect has injured others in the same way as the

present plaintiff is not a prerequisite for products liability claims, much less

is it a basis for excluding an expert’s testimony. Of course, a jury may

reasonably conclude that a lack of similar adverse events reduces the

likelihood of such events having occurred or undermines Dr. Jarrell’s

testimony; however, it has no bearing on the admissibility of his opinions.

28 IV. CONCLUSION

The defendants’ motions to exclude Dr. Jarrell’s expert testimony (Doc.

69 and Doc. 73) are denied without prejudice to my right to reassess such

conclusions at trial based on the evidence and opinions presented at that

time. 6 Additionally, as I have explained, I cannot determine on the present

record whether Dr. Jarrell’s causation opinion should be excluded on the

ground that it is based on an unwarranted assumption that all of the heat

energy produced by the use of the laser on non-vaporized prostate tissue was

conducted to the irrigation saline that came into contact with the energized

prostate tissue. Accordingly, I deny defendants’ request to exclude Dr.

Jarrell’s opinions on this basis without prejudice, and I will assess this

particular issue again de novo after conducting an evidentiary hearing.

SO ORDERED.

/s/ Paul J. Barbadoro Paul J. Barbadoro United States District Judge

Date March 26, 2024

cc: Counsel of Record

6 In preparing this memorandum and order, I have not considered either Dr. Jarrell’s supplemental affidavit (Doc. 96-1) nor the supplemental brief filed in response (Doc. 101). Instead, I will address these filings, if necessary, after holding the evidentiary hearing called for by this memorandum and order.

29