       NOTE: This disposition is nonprecedential.


  United States Court of Appeals
      for the Federal Circuit
                ______________________

                   HOLOGIC, INC.,
                     Appellant

                           v.

             MINERVA SURGICAL, INC.,
                       Appellee
                ______________________

                      2018-1550
                ______________________

    Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. IPR2016-
00868.
                 ______________________

                Decided: April 19, 2019
                ______________________

    MATTHEW M. WOLF, Arnold & Porter Kaye Scholer
LLP, Washington, DC, argued for appellant. Also repre-
sented by MARC A. COHN; JENNIFER SKLENAR, Los Angeles,
CA; SEAN MICHAEL CALLAGY, San Francisco, CA.

    MICHAEL T. ROSATO, Wilson Sonsini Goodrich & Rosati,
PC, Seattle, WA, argued for appellee. Also represented by
STEVEN W. PARMELEE; MATTHEW A. ARGENTI, Palo Alto,
CA.
2                     HOLOGIC, INC. v. MINERVA SURGICAL, INC.




                  ______________________

    Before NEWMAN, REYNA, and HUGHES, Circuit Judges.
HUGHES, Circuit Judge.
    This is a patent case involving a method to detect per-
forations during uterine ablation. Hologic, Inc., appeals a
decision of the Patent Trial and Appeal Board finding
claims of U.S. Patent No. 6,872,183 unpatentable as obvi-
ous. See Minerva Surgical, Inc. v. Hologic, Inc., No.
IPR2016-00868 (P.T.A.B. Oct. 5, 2017). Because we agree
with the Board’s construction of the term “monitoring for
the presence of a perforation in the uterus using a pressure
sensor,” and because substantial evidence supports the fac-
tual determinations underpinning the Board’s obviousness
conclusion, we affirm.
                              I
                             A.
     Hologic, Inc., owns the ’183 patent, which is directed to
a “method[] for detecting the presence of perforations in
body cavities” during ablation. ’183 patent col. 1 ll. 13–14.
Ablation is a medical procedure which involves distending
or inflating a body cavity with fluid and heating that fluid
to a sufficiently high temperature to destroy the cells lining
the cavity. It is often used to treat abnormal bleeding
within the endometrial layer of the uterus. Introducing
fluid into the uterus, however, creates several risks. For
example, if the uterus is perforated, “steam or hot fluids
generated during ablation, as well as portions of the medi-
cal device itself” can “escape the uterus and cause serious
injury to nearby organs.” J.A. 1583 ¶ 29. Electrical energy
can also cross through perforations and “caus[e] electrical
shock and thermal damage” to the body. J.A. 1583 ¶ 29.
   The ’183 patent addresses and minimizes these risks
by proactively “detecting the presence of perforations in
body cavities.” ’183 patent col. 1 ll. 13–14. It describes “a
HOLOGIC, INC. v. MINERVA SURGICAL, INC.                       3



system and method that pressurizes a body cavity and de-
tects whether the body cavity can maintain a pressurized
condition.” Id. col. 1 ll. 14–17; see also id. col. 2 ll. 38–43.
If the cavity cannot maintain a pressurized condition, “the
user is alerted that there may be a perforation in the or-
gan.” Id. col. 2 ll. 43–44.
    Independent claim 1 of the ’183 patent is representa-
tive for purposes of this appeal and is reproduced below.
    1. A method of ablating a uterus, comprising the
    steps of:
    inserting an ablation device into a uterus;
    flowing an inflation medium into the uterus;
    monitoring for the presence of a perforation in the
    uterus using a pressure sensor; and
    treating the interior of the uterus using the abla-
    tion device.
Id. col. 8 ll. 10–15.
                              B.
    Minerva Surgical, Inc., filed a petition for inter partes
review of the ’183 patent asserting that claims 1–15 are ob-
vious over various combinations of prior art references. Mi-
nerva relied on a total of seven references, four of which are
relevant to this appeal.
    First, U.S. Patent No. 5,891,094 (Masterson) describes
a method for thermally ablating the uterus. Masterson dis-
closes using a pressure sensor to monitor intrauterine pres-
sure and suggests optionally including a flow control sensor
to alert a physician “to a possible leak somewhere within
[the] system . . . or within the patient.” J.A. 1073.
     Second, U.S. Patent No. 3,871,374 (Bolduc) “is directed
to an instrument and method for monitoring the integrity
of the uterus and for dispensing a fluid . . . into both canals
4                     HOLOGIC, INC. v. MINERVA SURGICAL, INC.




of the Fallopian tubes of a female.” J.A. 1128. The device
in Bolduc only operates if it can apply a predetermined
fluid pressure within the uterus because “[w]eak, diseased
or ruptured uterus walls,” e.g., walls with a perforation,
will be unable to contain the device or maintain that fluid
pressure. J.A. 1130.
    Third, International PCT Application Publication No.
97/24074 (Isaacson) discloses an ablation device which uses
pressure transducers to “monitor the pressure of the fluid”
at different locations. J.A. 1090. If pressure readings vary,
Isaacson teaches that a “uterine perforation” may exist.
J.A. 1091.
     Finally, U.S. Patent No. 5,503,626 (Goldrath) is di-
rected to a system for monitoring the amount of fluid in the
uterus during ablation. The system in Goldrath measures
the differential between pressure readings at two locations.
If the differential exceeds a preset value, the patient may
be “absorbing too much fluid.” J.A. 1190. Goldrath de-
scribes “terminat[ing]” the procedure under such circum-
stances. J.A. 1190.
                             C.
     The Board instituted review on all asserted grounds.
Each of the grounds relied on a combination of prior art
references including either: (1) Masterson and Bolduc; or
(2) Isaacson and Goldrath.
     The Board determined that a person of ordinary skill
in the art was someone “who had, through education or
practical experience, the equivalent of a bachelor’s degree
in biomedical engineering, electrical engineering, mechan-
ical engineering or a related field and at least an additional
two to three years of work experience developing or imple-
menting electrosurgical devices.” J.A. 17. The Board re-
jected Hologic’s argument that a skilled artisan would need
experience specifically with uterine devices because the
’183 patent “explicitly discloses that the invention is
HOLOGIC, INC. v. MINERVA SURGICAL, INC.                    5



applicable to body cavities generally and indicates that the
problem with perforations is not unique to the ablation of
the uterus.” J.A. 16.
     Turning to the merits, the Board found that a skilled
artisan “would have been motivated to combine Masterson
and Bolduc to improve the safety of the ablation device.”
J.A. 25. The Board rejected Hologic’s contention that Mas-
terson did not describe claim 1’s step of “monitoring for the
presence of a perforation in the uterus using a pressure
sensor” and determined that Masterson and Bolduc, when
combined with other information in the prior art, disclosed
all the relevant limitations of the ’183 patent. The Board
therefore concluded that claims 1, 4, 6, 7, 9, 11–13, and 15
are obvious over Masterson and Bolduc; claim 5 is obvious
over Masterson, Bolduc, and Himmelstein; 1 claims 8 and
10 are obvious over Masterson, Bolduc, and Benaron; 2 and
claim 14 is obvious over Masterson, Bolduc, and Isaacson.
    The Board similarly found that a skilled artisan would
have been motivated to combine Isaacson and Goldrath to
improve the safety and efficacy of the claimed ablation de-
vices. The Board again denied Hologic’s assertion that the
prior art did not describe “monitoring for the presence of a
perforation in the uterus using a pressure sensor.” Be-
cause Isaacson and Goldrath, when combined with other
information in the prior art, disclosed all the relevant lim-
itations of the ’183 patent, the Board concluded that claims


    1   U.S. Patent No. 4,542,643 (Himmelstein) discloses
that testing pressure over a preselected time period is con-
ventional within the field.
    2   U.S. Patent No. 5,785,658 (Benaron) describes
monitoring the state of a device during minimally invasive
surgery and “produc[ing] an interlock control signal.” J.A.
1160. It further notes that “the feedback/interlock feature
of the analyzer can be overridden and/or disabled by the
surgeon as a matter of choice.” Id.
6                    HOLOGIC, INC. v. MINERVA SURGICAL, INC.




1–4, 6, 7, 9, and 11–15 are obvious over Isaacson and
Goldrath; claim 5 is obvious over Isaacson, Goldrath, and
Himmelstein; and claims 8 and 10 are obvious over Isaac-
son, Goldrath, and Benaron.
    Hologic appeals the Board’s construction of “monitor-
ing for the presence of a perforation in the uterus using a
pressure sensor” and its determinations as to level of skill
in the art and motivation to combine. We have jurisdiction
under 28 U.S.C. § 1295(a)(4)(A).
                             II
     Obviousness is a question of law based on underlying
factual findings. HTC Corp. v. Cellular Commc’ns Equip.,
LLC, 877 F.3d 1361, 1369 (Fed. Cir. 2017). Those factual
findings include (1) the scope and content of the prior art;
(2) the level of ordinary skill in the art; and (3) whether a
skilled artisan would be motivated to combine the prior art.
Kinetic Concepts, Inc. v. Smith & Nephew, Inc., 688 F.3d
1342, 1360 (Fed. Cir. 2012); see also Redline Detection, LLC
v. Star Envirotech, Inc., 811 F.3d 435, 449 (Fed. Cir. 2015).
We review the Board’s legal conclusions de novo and its fac-
tual findings for substantial evidence. Novartis AG v. Tor-
rent Pharm. Ltd., 853 F.3d 1316, 1324 (Fed. Cir. 2017).
Substantial evidence is “such relevant evidence as a rea-
sonable mind might accept as adequate to support a con-
clusion.” Id. (quoting Consol. Edison Co. v. NLRB, 305 U.S.
197, 229 (1938)).
                             A.
     We first address the Board’s construction of the
claimed step of “monitoring for the presence of a perfora-
tion in the uterus using a pressure sensor.” See ’183 patent
col. 8 ll. 13–14, 42–43. Minerva asserts that the Board did
not construe this step. It maintains that the relevant por-
tion of Board’s decision focused solely on the scope and con-
tent of the prior art. We disagree. Although the parties
did not expressly dispute the meaning of “monitoring for
HOLOGIC, INC. v. MINERVA SURGICAL, INC.                     7



the presence of a perforation in the uterus using a pressure
sensor” before the Board, Hologic impliedly argued “that
the monitoring must be only for a decrease in intrauterine
pressure that is caused by a perforation.” J.A. 27 (empha-
sis in original). The Board considered and rejected this
contention, noting instead that it “read the monitoring step
as encompassing monitoring for decrease in intrauterine
pressure that may be caused by a perforation but may al-
ternatively be caused by malfunctions in the equipment.”
J.A. 27. We find that, by espousing this reading of the
term, the Board construed the monitoring step to mean
“monitoring for any change in pressure regardless of
cause.” 3
    We review the Board’s claim construction, which here
relied solely on intrinsic evidence, de novo. See Teva
Pharm. USA, Inc. v. Sandoz, Inc., 135 S. Ct. 831, 841
(2015). The Board issued its decision on December 15,
2017. At that time, during inter partes review of an unex-
pired patent, the Board gave claims their “broadest




    3    Minerva implicitly acknowledges that the Board
performed some measure of claim construction. It contends
that “[r]ather than reading out any particular aspect of the
claims, the Board correctly observed that the monitoring
step of the claims do[es] not require monitoring for a pres-
sure anom[a]ly caused only by a perforation.” Resp. Br. 43
(emphasis in original). Minerva includes this assertion in
a section of its brief concluding that “[t]he Board’s findings
regarding the prior art disclosure demonstrate that it did
not interpret the claims in a way that eliminated the re-
quirement of monitoring for a perforation using a pressure
sensor.” Resp. Br. 46. While this conclusion purports to
focus on the Board’s factual findings, it also relates to the
way the Board interpreted the monitoring step, i.e., how it
construed the claim.
8                     HOLOGIC, INC. v. MINERVA SURGICAL, INC.




reasonable interpretation in light of the specification.” 4 37
C.F.R. § 42.100(b) (2017).
     On appeal, Hologic again argues that the monitoring
step requires monitoring only for changes in uterine pres-
sure caused by a perforation. We reject this contention.
The specification explains the pressure sensor “monitors
pressure” and delivers signals to a microprocessor, which
“determines if pressure in the body cavity . . . has failed to
achieve a predetermined threshold (indicating a perfora-
tion in the body cavity) or if it has and maintained the
threshold for a predetermined time period (indicating that
the body cavity has no perforation).” See ’183 patent col. 5
ll. 22–30. While the specification suggests that certain con-
ditions may reveal the possibility of perforation, the patent
does not limit the sensor’s monitoring to these situations.
Indeed, the specification explicitly notes that other issues,
such as kinked tubing, may lead to a “false test result.” See
id. col. 7 ll. 44–46. We thus decline to limit the “monitor-
ing” step as Hologic proposes. We instead construe the
monitoring step to mean “monitoring for any change in
pressure regardless of cause” because any change in pres-
sure might signify the existence of a perforation.
    Given our construction of “monitoring for the presence
of a perforation in the uterus using a pressure sensor,”


    4    The United States Patent and Trademark Office
has since revised its claim construction standard. See 83
Fed. Reg. 51,340, 51,358 (Oct. 11, 2018) (codified at
37 C.F.R. § 42.100(b)). As of November 13, 2018, the Board
construes a claim “in accordance with the ordinary and cus-
tomary meaning of such claim as understood by one of or-
dinary skill in the art and the prosecution history
pertaining to the patent.” 37 C.F.R. § 42.100(b). Our re-
view, however, is governed by the prior version of
37 C.F.R. § 42.100(b) because Minerva filed its petition
prior to November 13, 2018.
HOLOGIC, INC. v. MINERVA SURGICAL, INC.                     9



substantial evidence supports the Board’s determination
that Masterson discloses this step. Hologic argues that
Masterson is directed to maintaining a stable pressure in
the uterus rather than tracking changes in pressure. Ho-
logic is correct that Masterson emphasizes the importance
of maintaining a constant pressure, but it ignores that
Masterson also contemplates scenarios in which a constant
pressure cannot be maintained. For example, Masterson
describes attaching a “flow control sensor” to monitor the
flow of liquid into the uterus. See J.A. 1073. It notes that
“[b]y detecting a flow of liquid from fluid reservoir 176, the
care giver may be alerted to a possible leak somewhere
within system 160 or within the patient.” See J.A. 1073.
Pressure would not remain constant in the presence of a
leak because, as Hologic admits, leaks cause pressure to
decrease. Additionally, the system disclosed in Masterson
can be configured to alert users about abnormal operating
conditions “such as . . . over or under pressure.” See J.A.
1073. If Masterson can alert users to these conditions, then
it must be able to monitor for changes in pressure. And if
it can monitor for changes in pressure, then it discloses the
limitations of the monitoring step.
     Substantial evidence also supports the Board’s finding
that Isaacson discloses the type of monitoring claimed by
the ’183 patent. Isaacson describes monitoring pressure in
the uterus by calculating “the differential between the two
transducers.” J.A. 1090. It explains that these pressure
readings impact fluid flow rate and that, “by monitoring
the volume and flow rate of the fluid discharged from the
uterus and comparing [it] with the monitored volume and
flow rate of the . . . fluid charged to the uterus, the possi-
bility of the uterine perforation can be detected.” J.A. 1091.
In other words, it discloses monitoring for changes in pres-
sure and suggests that a perforation may cause any ob-
served change. It thus teaches the monitoring claimed by
the ’183 patent.
10                    HOLOGIC, INC. v. MINERVA SURGICAL, INC.




                              B.
    We next consider the finding that a skilled artisan need
not have experience with uterine ablation devices. Hologic
contends that a skilled artisan must have experience work-
ing with uterine ablation devices, not just any electrosur-
gical device, because the claims are directed to solving
issues specifically associated with uterine ablation.
     “Factors that may be considered in determining level
of ordinary skill in the art include: (1) the educational level
of the inventor; (2) type of problems encountered in the art;
(3) prior art solutions to those problems; (4) rapidity with
which innovations are made; (5) sophistication of the tech-
nology; and (6) educational level of active workers in the
field.” Daiichi Sankyo Co. v. Apotex, Inc., 501 F.3d 1254,
1256 (Fed. Cir. 2007) (quoting Envtl. Designs, Ltd. v. Union
Oil Co., 713 F.2d 693, 696 (Fed. Cir. 1983)).
     Substantial evidence supports the Board’s determina-
tion that a skilled artisan was someone who had “experi-
ence developing or implementing electrosurgical devices”
generally rather than uterine devices specifically. See J.A.
17. While the claims are directed to uterine ablation, the
patent specification speaks in terms of “body cavities,” with
the uterus comprising just one example of a body cavity.
See ’183 patent col. 1 ll. 12–17, 20–21, 22–25, 28–33, 49–
57; id. col. 2 ll. 13–17, 31–34, 35–44, 45–58; id. col. 7 l. 63–
col. 8 l. 8. The specification also notes that, although the
description of the preferred embodiment “is with reference
to a perforation detection system having a device usable to
ablate tissue within a uterus, the present invention is ap-
plicable to perforation detection within other body cavi-
ties.” Id. col. 7 ll. 63–66. The patent further states that
“[t]hose having ordinary skill in the art will certainly un-
derstand from the embodiment disclosed herein that many
modifications are possible without departing from the
teachings hereof” and that “[a]ll such modifications are in-
tended to be encompassed within the following claims.” Id.
HOLOGIC, INC. v. MINERVA SURGICAL, INC.                    11



col. 8 ll. 4–8. The prior art, furthermore, treats inventions
directed to uterine ablation as representative of inventions
directed to other body cavities. For example, Masterson
describes “methods and devices for thermally ablating hol-
low body organs, such as the uterus.” J.A. 1065 (emphasis
added). Given these disclosures, we cannot say that the
record lacks sufficient “relevant evidence as a reasonable
mind might accept as adequate to support” the Board’s
findings. See Novartis, 853 F.3d at 1324.
     Hologic argues that we should reverse because the
Board failed to expressly consider all the factors discussed
in Daiichi. We have cautioned, however, that the Daiichi
factors “are not exhaustive but are merely a guide.” See
Daiichi, 501 F.3d at 1256. The Board was not required to
analyze level of skill in the art on a factor-by-factor basis.
It is enough that it applied the principle of Daiichi and as-
sessed level of skill in the art on a holistic basis.
                               C.
    Finally, we address the finding that a skilled artisan
would have been motivated to combine Masterson with
Bolduc and Isaacson with Goldrath. 5 Hologic contends
that there is no evidence that combining either set of refer-
ences would improve safety.
     The Board found that a skilled artisan would have been
motivated to combine Masterson and Bolduc because incor-
porating Bolduc’s pressure-based perforation monitoring
into Masterson’s ablation device would have improved the
device’s safety. Substantial evidence supports this deter-
mination. Masterson discloses monitoring for abnormal
operating conditions and, if such conditions arise, automat-
ically ceasing the operation “to provide increased safety to


    5    In reaching this issue, we reject Hologic’s conten-
tion that the Board did not adequately explain the bases
for its determinations.
12                    HOLOGIC, INC. v. MINERVA SURGICAL, INC.




the patient.” J.A. 1073. Bolduc describes monitoring for
abnormal conditions in the uterus before performing med-
ical procedures. As Minerva’s expert, Dr. Pearce, 6 testified,
a “skilled artisan would reasonably have incorporated pres-
sure-based perforation monitoring” of Bolduc to the abla-
tion device of Masterson “in order to maximize the
usefulness of the pressure sensor in Masterson’s system
and method, and also improve the safety of the ablation de-
vice and treatment procedure.” J.A. 773 ¶ 59. Hologic con-
tends that a skilled artisan would not have thought to
combine Masterson and Bolduc because their systems are
incompatible. We agree with the Board, however, that any
alleged incompatibility would not preclude a motivation to
combine because “[t]he test for obviousness is what the
combined teachings of the references would have suggested
to one of ordinary skill in the art, not whether the features
of a secondary reference may be bodily incorporated into
the structure of the primary reference.” J.A. 29 (citing In
re Mouttet, 686 F.3d 1322, 1332 (Fed. Cir. 2012)).
    Substantial evidence also supports the determination
that a skilled artisan would have been motivated to com-
bine Isaacson and Goldrath to improve safety. Both refer-
ences discuss detecting perforations by measuring



     6   Hologic argues that the Board erred in considering
Dr. Pearce’s testimony because he lacked enough experi-
ence with uterine ablation devices. Because we find no er-
ror in the Board’s finding regarding level of skill in the art,
we hold that it did not abuse its discretion in crediting the
testimony of Dr. Pearce, who “has extensive knowledge re-
lated to the design of electrosurgical ablation devices and
some knowledge of endometrial ablation devices.” J.A. 51;
see Yorkey v. Diab, 601 F.3d 1279, 1284 (Fed. Cir. 2010)
(noting that “[w]e defer to the Board’s findings concerning
the credibility of expert witnesses”).
HOLOGIC, INC. v. MINERVA SURGICAL, INC.                   13



pressure. Isaacson describes using multiple pressure sen-
sors to monitor intrauterine pressure and explains that dif-
ferent pressure readings between locations may indicate
the presence of a perforation. Goldrath discloses that a
user can measure pressure to determine whether “the
amount of fluid leaving the uterus is less than the amount
entering,” i.e., whether there is a leak. J.A. 1190, 1192.
Both references also discuss preventing ablation if the sys-
tem detects an issue with pressure. Isaacson, for instance,
discloses using a safety circuit to prevent ablation if elec-
trodes in the uterus are not submerged in fluid. Goldrath
describes “terminat[ing]” treatment if there are any abnor-
mal operating conditions, such as inadequate pressure.
J.A. 1190. Given these similarities, we agree that a skilled
artisan would have been motivated to apply the teachings
of Goldrath to Isaacson’s pressure sensor. As Dr. Pearce
explained, “a skilled artisan would have recognized that
Isaacson’s endometrial ablation method would benefit from
a safety mechanism that prevents treatment if the pres-
sure test fails, such as disclosed by the combination of
Isaacson and Goldrath.” J.A. 812 ¶ 169.
    Hologic asserts that a skilled artisan would not have
combined these references because they do not disclose any
issues with safety which might incentivize improvement.
We disagree. The lack of any specific safety concerns does
not preclude a motivation to make a device safer. As Ho-
logic’s expert, Dr. Martin, admitted, there are times when
it may be beneficial to add redundant safety features to a
medical device.
    With respect to claim 7, 7 Hologic argues that a skilled
artisan would not have added any pre-treatment steps to
the inventions of Masterson or Isaacson because lengthen-
ing the procedure runs counter to conventional wisdom.


    7   Claim 7 prevents treatment until after the moni-
toring step is complete.
14                   HOLOGIC, INC. v. MINERVA SURGICAL, INC.




Minerva’s expert, Dr. Mirabile, 8 however, testified that “a
physician performing endometrial ablation procedures in
November 1999 would gladly have extended the duration
of the procedure if the ultimate result was a safer treat-
ment for the patient.” J.A. 31. Indeed, Dr. Mirabile noted
that a system already existed that lengthened the proce-
dure to check for perforations prior to ablation. Thus, evi-
dence shows that adding a pre-treatment step that would
require lengthening the time of the procedure would not
have dissuaded a skilled artisan from combining the rele-
vant references.
                            III
    We have considered the parties’ remaining arguments
and find them unpersuasive. We conclude that the Board
correctly construed the step of “monitoring for the presence
of a perforation in the uterus using a pressure sensor” and
that substantial evidence supports the Board’s determina-
tions regarding level of skill in the art and motivation to
combine. Therefore, we affirm the decision of the Patent
Trial and Appeal Board that the challenged claims of the
’183 patent are invalid as obvious.
                       AFFIRMED




     8   Hologic argues that the Board erred in considering
Dr. Mirabile’s testimony because he had not reviewed the
prior art references at issue in this case. The Board noted,
however, that “Dr. Mirabile’s testimony is not directed to
the combination of the asserted prior art references, but to
the conventional wisdom with regards to endometrial abla-
tion at the relevant time period.” J.A. 52. We find no abuse
of discretion in the Board’s determination that Dr. Mirabile
had enough knowledge and skill to testify about this topic.
