       NOTE: This disposition is nonprecedential.


  United States Court of Appeals
      for the Federal Circuit
                ______________________

                  NUVASIVE, INC.,
                     Appellant

                           v.

    ANDREI IANCU, UNDER SECRETARY OF
  COMMERCE FOR INTELLECTUAL PROPERTY
   AND DIRECTOR OF THE UNITED STATES
     PATENT AND TRADEMARK OFFICE,
                  Intervenor
            ______________________

                      2017-1666
                ______________________

    Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. 95/001,888.
                  ______________________

              Decided: November 9, 2018
               ______________________

    MICHAEL T. ROSATO, Wilson, Sonsini, Goodrich &
Rosati, PC, Seattle, WA, argued for appellant. Also
represented by SONJA ROCHELLE GERRARD; GRACE J. PAK,
PAUL DAVID TRIPODI, II, Los Angeles, CA; RICHARD
TORCZON, Washington, DC.

   BENJAMIN T. HICKMAN, Office of the Solicitor, United
States Patent and Trademark Office, Alexandria, VA,
2                                   NUVASIVE, INC. v. IANCU




argued for intervenor. Also represented by THOMAS W.
KRAUSE, FRANCES LYNCH.
                ______________________

    Before NEWMAN, CHEN, and HUGHES, Circuit Judges.
CHEN, Circuit Judge
     NuVasive, Inc. (NuVasive) appeals from the decision
of the U.S. Patent and Trademark Office, Patent Trial
and Appeal Board (Board) in an inter partes reexamina-
tion proceeding holding claims 17–22 and 24–27 of U.S.
Patent No. 7,691,057 obvious. The ’057 patent is directed
to a surgical access system and related methods for creat-
ing minimally invasive operative corridors through tissue
with significant neural structures. ’057 patent col. 2 l.
61–col. 3 l. 7. Because the PTO admits that its construc-
tion of “lateral, trans-psoas path to the targeted lumbar
spinal disc” was too broad, we modify its construction to
align with the construction we adopted in In re NuVasive,
Inc., 693 F. App’x 893 (Fed. Cir. 2017) (NuVasive I) for a
very similar term. As to secondary considerations, we
conclude that the Board erred in finding no nexus be-
tween NuVasive’s claimed method and its commercial
“eXtreme Lateral Interbody Fusion” (XLIF) surgical
technique. And we conclude that further fact finding is
needed as to whether WIPO Publication No. WO 01/37728
(Kelleher) teaches a nerve-monitoring technique for the
iliohypogastric and ilioinguinal nerves. Accordingly, we
vacate the Board’s obviousness determination and re-
mand for the Board to conduct a new analysis consistent
with this opinion.
                      BACKGROUND
                            A
    Interbody fusion is a commonly used surgical proce-
dure to address pain associated with damaged interverte-
bral discs. The procedure involves removing some or all of
NUVASIVE, INC. v. IANCU                                  3



a damaged disc and inserting an implant in place of the
disc. There are three primary approaches to this spinal
surgical area: posterior, anterior, and lateral. While the
lateral approach (from the side of the patient’s body)
provides the most direct route to the disc space, one major
obstacle is the lumbar plexus, a network of nerves origi-
nating in the spinal column and exiting through the
opening of the lumbar vertebra. The lumbar plexus runs
through the psoas muscle and is found in the posterior
portion of the muscle. The nerves of the lumbar plexus
innervate (i.e., supply) the leg and pelvic region with
sensory and motor neurons. Surgery through the lumbar
plexus is challenging because the nerves are anatomically
tethered to the spinal column so they cannot be easily
moved out of the surgical path. And damage to the nerves
in the lumbar plexus can have serious side effects, includ-
ing motor function impairment and extreme pain.
    As a result, before the patented method, surgeons
traditionally performed interbody fusion procedures from
the posterior aspect (back) or anterior aspect (front) of a
patient. These approaches, however, also had their
drawbacks. The posterior approach required removing
the bony processes from the spine and was associated
with a higher incidence of neural complications from
damage to the paraspinal nerves emanating from the rear
of the spinal column. The anterior approach risked dam-
aging internal organs and major blood vessels.
    NuVasive’s ’057 patent addressed these challenges by
making a lateral approach through the psoas muscle
safer. NuVasive markets this trans-psoas surgical system
and procedure under the tradename “eXtreme Lateral
Interbody Fusion” or “XLIF.”
    The ’057 patent, entitled “Surgical Access System and
Related Methods,” covers a surgical access system and
related methods for creating a minimally invasive opera-
tive corridor through tissue with significant neural struc-
4                                     NUVASIVE, INC. v. IANCU




tures. ’057 patent col. 2 l. 61–col. 3 l. 7. This access
system and related method involve: (1) distracting the
tissue between the patient’s skin and surgical target site
to create a distraction corridor, (2) retracting the distrac-
tion corridor to establish and maintain an operative
corridor, and (3) detecting the existence of neural struc-
tures before and during the establishment of the opera-
tive corridor. Id. at col. 3 ll. 8–19. Nerve-monitoring (i.e.,
electromyography (EMG)) is accomplished with electrodes
attached to the instruments used to create the operative
corridor. Id. at col. 12 ll. 17–52. These electrodes emit a
charge as the instruments advance through the body. Id.
When the charge reaches a nerve, the nerve stimulates
the muscle group it controls, and a surgeon observes the
associated muscle twitch. Id. This muscle twitch data
can also be fed into a graphical user interface that dis-
plays information about an instrument’s direction and
relation relative to nearby nerves. Id.
    Claim 17, from which all of the challenged claims de-
pend, covers NuVasive’s surgical access system and
related methods. It reads:
    A method of accessing a surgical target site within
    a spine, comprising the steps of:
        (a) creating a distraction corridor along a lat-
    eral, trans-psoas path to a targeted lumbar spinal
    disc in a lumbar spine using a distraction assem-
    bly comprising at least two dilators that are se-
    quentially inserted along the lateral, trans-
    psoas path to the targeted lumbar spinal
    disc, and performing neuromonitoring during at
    least a portion of the time the distraction assem-
    bly is used in creating the distraction corridor
    along the lateral, trans-psoas path, wherein
    the neuromonitoring comprises causing the emis-
    sion of a plurality of electrical stimulation signals
    from a stimulation electrode provided on a distal
NUVASIVE, INC. v. IANCU                                     5



    portion of at least one component of the distrac-
    tion assembly and monitoring for resulting elec-
    tromyographic (EMG) activity after the emission
    of each stimulation signal, and wherein the com-
    ponent of the distraction assembly is coupled to a
    control unit of a neuromonitoring system that is
    capable of displaying to a user an indication of at
    least one of proximity and direction of a nerve to
    the stimulation electrode provided on the compo-
    nent of the distraction assembly based on the
    monitored resulting electromyographic (EMG) ac-
    tivity;
         (b) slidably advancing a plurality of retractor
    blades of a retraction assembly along an outer-
    most dilator of the at least two dilators of the dis-
    traction assembly, the retraction assembly
    comprising a handle assembly coupled to the plu-
    rality of retractor blades such that the retractor
    blades extend generally perpendicularly relative
    to arm portions of the handle assembly, each of
    said plurality of retractor blades having a general-
    ly concave inner face and a generally convex exte-
    rior face, said handle assembly being capable of
    moving said plurality of retractor blades from a
    closed position to an open position, said closed po-
    sition being characterized by said plurality of re-
    tractor blades being positioned to abut one
    another and form a closed perimeter, said open
    position characterized by said plurality of retrac-
    tor blades being positioned generally away from
    one another and forming an open perimeter;
        (c) simultaneously introducing said plurality
    of retractor blades over the outermost dilator of
    said distraction assembly along the lateral,
    trans-psoas path to the targeted lumbar spi-
    nal disc while in said closed position;
6                                      NUVASIVE, INC. v. IANCU




        (d) actuating said handle assembly to move
    said plurality of retractor blades to the open posi-
    tion so that the plurality of retractor blades create
    an operative corridor along the lateral, trans-
    psoas path to the targeted lumbar spinal disc;
        (e) releasably engaging a fixation element
    with at least one of the plurality of retractor
    blades so that a distal portion of the fixation ele-
    ment extends distally from the at least one retrac-
    tor blade and penetrates into a lateral aspect of
    the lumbar spine, wherein the fixation element
    secures the at least one retractor blade to the
    lumbar spine;
        (f) inserting an implant through the operative
    corridor created by the plurality of retractor
    blades along the lateral, trans-psoas path to
    the targeted lumbar spinal disc.
Id. at col. 16 l. 28–col. 17 l. 3 (emphases added).
    Like the method claimed in the ’057 patent, NuVa-
sive’s XLIF procedure involves inserting an implant
through a trans-psoas operative corridor. The operative
corridor is created by inserting sequential dilators along a
lateral trans-psoas path to the lumbar spine. A retractor
instrument is then advanced over the last inserted dila-
tor, and a fixation element is engaged to maintain the
operative corridor. During this process, EMG electrodes
mounted on the surgical instruments and connected to
NuVasive’s NeuroVision® System allows surgeons to
monitor the placement of the surgical instruments rela-
tive to nearby neural structures.
                              B
    NuVasive sued Globus Medical, Inc. for infringement
of the ’057 patent on October 5, 2010, and Globus filed a
request for an inter partes reexamination on February 8,
NUVASIVE, INC. v. IANCU                                    7



2012, relying on several prior art references. The Exam-
iner ordered a reexamination on claims 17–22 and 24–27.
                          1. Prior Art
    Kossmann 1 describes establishing a narrow operative
corridor from the side of the patient’s body to repair
injuries to the spine. After making an incision, surgeons
used a table-fixed retractor system to open the path to the
affected vertebra. “To reach the vertebral bodies of the
lumbar spine, the psoas muscle was mobilized at least in
part and pushed backwards to reach the lateral aspect of
the vertebra. . . . Splitting of the psoas muscle along its
fibers had to be done in very athletic patients, since the
excessive size of the muscle did not allow a direct lateral
access to the vertebra.” J.A. 12636. This splitting was
performed using a “blunt dissection” technique involving
the surgeon’s finger or a wet sponge mounted on a stick to
carefully separate the tissue. J.A. 12635–36.
    Branch 2 discloses using a retractor for creating surgi-
cal access channels and specifically contemplates inter-
body fusion and disc replacement surgeries. ’933 patent
(Branch) col. 2 ll. 47–51. After a surgeon makes an initial
incision, she sequentially advances dilators through the
incision to gradually widen the space of the operative
corridor. Id. Once the operative corridor is the desired
size, the surgeon positions a retractor over the last insert-
ed dilator to maintain a working channel. Id.




    1   Thomas Kossmann et al., Minimally Invasive Ver-
tebral Replacement with Cages in Thoracic and Lumbar
Spine, 6 Euro. J. of Trauma 292–300 (2001).
    2   U.S. Patent No. 6,945,933, entitled “Instruments
and Methods for Minimally Invasive Tissue Retraction
and Surgery.”
8                                    NUVASIVE, INC. v. IANCU




    Koros 3 teaches a variable length retractor designed to
“hold organs, muscles, arteries, and other tissue out of the
way” during surgery. ’139 patent (Koros) col. 1 ll. 34–50.
     Kelleher 4 describes a system for “detecting the pres-
ence of a nerve near a surgical tool or probe.” WO
01/37728 (Kelleher), Abstract. Kelleher observes that “it
is especially important to sense the presence of spinal
nerves when performing spinal surgery, since these
nerves are responsible for the control of major body func-
tions.” Id. at col. 1 ll. 15–17. The detection system relies
on EMG to detect responses in the muscles controlled by
the relevant nerves. Id. at col. 10 ll. 7–9. The system
employs surgical tools with electrified cannuale through
which other surgical tools are introduced into the patient.
Id. at col. 16 ll. 15–27. These electrified cannulae emit an
electric charge, which stimulates nerves, and these nerves
in turn stimulate certain muscle groups to twitch. Id. at
col. 12 ll. 21–34. The relevant muscle groups for lumbar
spinal surgery are those in the patient’s legs. Id. at col.
21 ll. 15–25. NuVasive is the assignee of the Kelleher
application.
        2. First Office Action and Board Decision
    In the first office action in the reexamination, the Ex-
aminer rejected the claims as obvious over Kossmann,
Branch, Koros, and Kelleher. The Examiner found that
Kossmann discloses a trans-psoas approach to spinal
surgery; Branch teaches using a series of sequential
dilators and a retractor assembly for creating an opera-
tive corridor; Koros describes fixation screws that screw
into the vertebrae at opposite sides of an affected disc;



    3   U.S. Patent No. 5,928,139, entitled “Retractor
with Adjustable Length Blades and Light Pipe Guides.”
    4   WIPO Publication No. WO 01/37728, entitled
“Electromyography Systems.”
NUVASIVE, INC. v. IANCU                                    9



and Kelleher discloses EMG nerve-monitoring. Because
all these references pertain to minimally invasive surgical
techniques, the Examiner found that it would have been
obvious to a skilled artisan to combine them to arrive at
the claimed surgical system and related method.
     In response, NuVasive presented two theories of non-
obviousness and testimony from Dr. Jim Youssef, an
orthopedic surgeon, to support these theories. First,
NuVasive argued that none of the prior art taught creat-
ing an operative corridor along a lateral, trans-psoas path
using dilators and retractors, as recited in the claims of
the ’057 patent. Kossmann primarily discussed moving
the psoas muscle aside and only mentioned splitting the
psoas muscle along its fibers in athletic patients with
large psoas muscles. Even in those patients, surgeons
split the psoas muscle with blunt dissection (using a
finger or sponge on a stick), not with dilators and retrac-
tors. Blunt dissection, NuVasive asserted, was safer than
dilation and retraction because surgeons viewed a sponge
or finger as a safer tool than a dilator or retractor. Second
NuVasive argued that while Kelleher is directed to sys-
tems for detecting the presence of nerves during surgical
procedures, it does not teach monitoring nerves along a
“lateral, trans-psoas path to the targeted lumbar spinal
disc.” J.A. 348. NuVasive also argued that there was no
reasoned explanation in the office action or reexamination
request to support Globus’s motivation to combine Kelle-
her with Branch, Kossmann, and Koros.
    Globus responded with expert testimony from Dr.
Isador Lieberman, an orthopedic surgeon specializing in
spinal surgery. Dr. Lieberman rejected NuVasive’s theory
that “blunt dissection” was safer than using dilators and
retractors. Dr. Lieberman explained that “both tech-
niques do the exact same thing for the exact same pur-
pose” and that “one of ordinary skill in the art would have
understood how to penetrate a distractor and retractor
assembly through the psoas muscle.” J.A. 435. This is
10                                  NUVASIVE, INC. v. IANCU




because skilled artisans were familiar with how to split
psoas-muscle tissue in line with its fibers to minimize
damage to the nerves, and NuVasive’s approach merely
used ubiquitous surgical tools such as retractors to do so.
Dr. Lieberman also opined that, because “Kelleher dis-
closes a nerve detection system for use with surgical tools
or probes for spinal surgery, one of ordinary skill in the
art would understand how to [use it to] achieve an even
greater ability to negotiate around important neuronal
structures during trans-psoas operations.” J.A. 436.
    After considering the evidence, the Examiner con-
cluded that the challenged claims would not have been
obvious. The Examiner found that the prior art did not
expressly teach dissection of the psoas muscle using a
dilator and retractor, and “Kossman[n] [taught] using a
trans-psoas approach for only a few patients and even
then, using blunt dissection.” J.A. 530–31. The Examiner
also found that Kelleher did not explicitly teach using
nerve-monitoring in the lateral, trans-psoas context even
though Kelleher did teach its use in lumbar spinal sur-
gery. Globus appealed to the Board.
    The Board reversed the Examiner, finding the “blunt-
dissection” methods described in Kossmann not meaning-
fully different from the ’057 patent’s dilators and retrac-
tor. Specifically, the Board found that the Examiner
“erred in concluding that one of ordinary skill in the art
would not have considered the use of a dilator, as taught
by Branch, to be an alternative ‘blunt instrument’ suita-
ble for use in a ‘blunt dissection’ of the psoas muscle.”
J.A. 955. “Branch evinces that a dilator is an alternative
‘blunt instrument’ that would appear to provide a more
precise and gradually increasing pathway as compared to
a surgeon’s finger or wet sponge on a stick, as taught by
Kossmann.” J.A. 856. The Board also disagreed with the
weight the Examiner placed on the fact that Kossmann
disclosed only splitting the psoas muscle in very athletic
patients. “[A]ny need or problem known in the field of
NUVASIVE, INC. v. IANCU                                   11



endeavor at the time of the invention and addressed by
the patent can provide a reason for combining the ele-
ments in the manner claimed.” KSR Int’l Co. v. Teleflex
Inc., 550 U.S. 398, 420 (2007). Thus, the Board deter-
mined that the problem of providing a lateral approach in
“very athletic patients” is a reason that the skilled artisan
would have used a lateral trans-psoas approach as taught
by Kossmann.
    The Board also disagreed with the Examiner’s find-
ings on Kelleher. The Board found that it would have
been obvious to a skilled artisan to look to Kelleher’s
nerve-monitoring system because Branch and Kossmann
both teach the desirability of avoiding nerves in spinal
surgery, and Kelleher itself discloses use in a minimally-
invasive spinal surgical system.
                   3. Claim Amendment
    The Board’s reversal of the Examiner’s decision creat-
ed a new ground of rejection. 37 C.F.R. § 41.77(f) (2016).
NuVasive chose to reopen prosecution rather than seek
reconsideration of the Board’s decision.        NuVasive
amended claim 17 to include the use of nerve-monitoring
technology—a limitation already recited in some of the
other challenged claims—and offered objective evidence of
nonobviousness supported by the declarations of three
witnesses. After NuVasive submitted its new evidence,
and before the Examiner issued the next office action,
NuVasive and Globus settled, and Globus ended its
participation in the reexamination.
                 4. Second Board Decision
    After the claim amendment, the Examiner once again
found the claims to be nonobvious. Specifically, the
Examiner found that none of the references taught nerve-
monitoring during a lateral, trans-psoas spinal procedure.
For Kelleher to be properly combined with the other
references, the Examiner stated that, “Kelleher must
12                                  NUVASIVE, INC. v. IANCU




provide some suggestion or teaching to apply the taught
neuromonitoring during a lateral trans-psoas spinal
procedure.” J.A. 2801. And Kelleher, the Examiner
concluded, does not. Id. The Examiner also found NuVa-
sive’s objective evidence of nonobviousness persuasive.
The Examiner cited an article touting “the use of real-
time directional neuromonitoring to ensure a safe passage
through the psoas-muscle,” as “a feature contributing to
the success of the patent under reexamination.” J.A.
2802.
    Although Globus had ceased its participation in the
reexamination proceedings, the Examiner’s patentability
decision returned to the Board for review under 37 C.F.R.
§ 41.77(f). The Board once again reversed the Examiner.
In its second decision, the Board offered three additional
rationales and reiterated its previous reasoning to sup-
port its obviousness findings.
    First, the Board construed the phrase “lateral, trans-
psoas path to the targeted lumbar spinal disc.” J.A. 8–10.
While it previously did not feel the need to construe the
term, the Board found construction necessary after NuVa-
sive introduced objective evidence of nonobviousness. Id.
The Board concluded that the broadest reasonable inter-
pretation of the phrase “encompasses a path, to the lum-
bar spinal disc, which passes through any portion of the
psoas muscle, regardless of the portion, and which is to
the lateral side of the body, to any significant degree, as
compared to an anterior puncture.” J.A. 10.
    Second, the Board once again disagreed with the Ex-
aminer that Kelleher must provide some suggestion or
teaching to apply neuromonitoring to a lateral trans-
psoas spinal procedure. The Board found that Kelleher’s
neuromonitoring technology achieves Kossmann’s and
Branch’s desire to avoid nerves, and Kelleher itself dis-
closes the use of nerve-monitoring in a minimally invasive
spinal surgical system. The Board found that it “is of no
NUVASIVE, INC. v. IANCU                                  13



moment that the nerves sought to be avoided in
Kossmann[‘s lateral approach] are the iliohypogastric and
ilioinguinal nerves[;] these are still nerves that Kossmann
teaches should be avoided in a lateral approach.” J.A. 12.
While these nerves may not be present in the psoas
muscle, both are still part of the lumbar plexus, which the
’057 patented method seeks to avoid. The Board also
rejected NuVasive’s argument that Kossmann only teach-
es traversing a “safe zone” of the psoas muscle where the
important neural structures do not reside. The ’057
patent does not define any particular “lateral, trans-psoas
path to the targeted lumbar spinal disc,” and the claims
themselves do not recite the step of navigating through
the lumbar plexus or any particular nerves. Thus even if
Kossmann’s lateral trans-psoas path does not implicate
the majority of the lumbar plexus, because Kossmann
expressly teaches avoiding the iliohypogastric and ili-
oinguinal nerves, the Board found that no additional
nerves need be avoided for the prior art to suggest that a
skilled artisan would be motivated to include a nerve-
monitoring step during the creation of the operative
corridor.
    Third, the Board found that NuVasive’s objective evi-
dence carried little weight due to a lack of nexus with the
challenged claims. “For objective evidence to be accorded
substantial weight, its proponent must establish a nexus
between the evidence and the merits of the claimed inven-
tion.” In re GPAC Inc., 57 F.3d 1573, 1580 (Fed. Cir.
1995). In particular, the objective indicia “must be tied to
the novel elements of the claim at issue” and “be reasona-
bly commensurate with the scope of the claims.” Institut
Pasteur & Universite Pierre Et Marie Curie v. Focarino,
738 F.3d 1337, 1347 (Fed. Cir. 2013). The Board conclud-
ed that NuVasive had failed to prove this nexus based on
two grounds. Using its construction of “lateral, trans-
psoas path,” the Board noted that claim 17 of the ’057
patent is not limited to the lateral approach used in the
14                                 NUVASIVE, INC. v. IANCU




XLIF procedure, but instead encompasses any psoas-
traversing approach that is lateral to the midline to any
significant degree. The Board thus found that the XLIF
procedure, is not reasonably commensurate with the scope
of the claims. J.A. 19–20.
    Next, the Board found that NuVasive’s evidence failed
to adequately establish what actually comprises the XLIF
procedure and whether it is encompassed by claim 17 of
the ’057 patent. While NuVasive did provide a claim
chart mapping the features of claim 17 to its XLIF system
and procedure, the Board concluded it was unable to
discern whether the MaXcess® II Access System and
NeuroVision® System, to which the chart refers, were part
of the XLIF system. The Board also noted that NuVa-
sive’s marketing materials at times used XLIF as a mar-
keting term to identify a surgical technique and used
XLIF at other times to identify groups of products. The
Board concluded that, “when [NuVasive] uses the short-
hand term ‘XLIF’ in its Request [to Reopen Prosecution],
without clarification, we are unable to associate [NuVa-
sive’s] objective evidence with particular products or
features.” J.A. 18. Thus, while NuVasive presented
evidence of long-felt need, skepticism followed by praise
and recognition, and commercial success, the Board was
not persuaded by NuVasive’s evidence due to this lack of
nexus. The Board additionally found NuVasive’s objective
evidence of nonobviousness insufficient.
    Taking all of the evidence into consideration, the
Board concluded that claim 17 as amended, and the
claims that depend therefrom, would have been obvious.
NuVasive appeals the Board’s second decision under
35 U.S.C. §§ 141 and 142. We have jurisdiction under
28 U.S.C. § 1295(a)(4)(A).
NUVASIVE, INC. v. IANCU                                  15



                          DISCUSSION
                              A
    “Obviousness is a question of law based on underlying
findings of fact.” In re Kubin, 561 F.3d 1351, 1355 (Fed.
Cir. 2009). We review the Board’s decisions under the
standards set forth in § 706 of the Administrative Proce-
dure Act (APA). We set aside the Board’s decisions if they
are “arbitrary, capricious an abuse of discretion, or other-
wise not in accordance with law” or “unsupported by
substantial evidence.” 5 U.S.C. § 706(2) (2012). We
review the Board’s legal conclusions de novo and its
factual findings for substantial evidence. In re Gartside,
203 F.3d 1305, 1316 (Fed. Cir. 2016). A finding of fact is
supported by substantial evidence if a reasonable mind
might accept the evidence as adequate support for the
finding. Consol. Edison Co. v. NLRB, 305 U.S. 197, 229
(1938). “If the evidence in [the] record will support sever-
al reasonable but contradictory conclusions, we will not
find the Board’s decision unsupported by substantial
evidence simply because the Board chose one conclusion
over another plausible alternative.” In re Jolley, 308 F.3d
1317, 1320 (Fed. Cir. 2002).
                              B
    NuVasive presents three primary arguments on ap-
peal. First, NuVasive contends that the Board erred in its
construction of the term “lateral, trans-psoas path to the
targeted lumbar spinal disc.” Specifically, NuVasive
argues that the Board erred by failing to consider how the
term “lateral” was used in the context of the ’057 patent.
Second, NuVasive claims the Board erred in disregarding
the evidence of secondary considerations by using its
overly broad claim construction of “lateral, trans-psoas
path to the targeted lumbar spinal disc” to conclude that
the claims were not reasonably commensurate with the
objective evidence and that the Board misunderstood the
scope of the XLIF procedure. Third, NuVasive argues
16                                    NUVASIVE, INC. v. IANCU




that the Board committed legal error because its obvious-
ness determination lacks a motivation to combine the
prior art references. We address each of these issues in
turn below.
                             C
    Because NuVasive’s appeal turns in part on the con-
struction of “lateral, trans-psoas path to the targeted
lumbar spinal disc,” we address the claim construction
issue below first.
    The Board construed the term “lateral, trans-psoas
path to the targeted lumbar spinal disc” as encompassing
“a path to the lumbar spinal disc, which passes through
any portion of the psoas muscle, regardless of the portion,
and which is to the lateral side of the body, to any signifi-
cant degree, as compared to an anterior puncture.” J.A.
10. NuVasive contends that this construction is unrea-
sonably broad, and on appeal, the PTO concedes that the
Board’s construction might be too broad in light of our
opinion in In re NuVasive, Inc., 693 F. App’x 893 (Fed.
Cir. 2017) (NuVasive I). We issued a non-precedential
opinion in NuVasive I shortly after NuVasive filed its
notice of appeal in this case. NuVasive I was an appeal
from an inter partes review filed by Medtronic, Inc. on
U.S. Patent No. 8,016,767, which shares a very similar
specification with the ’057 patent. 693 F. App’x at 894–
95. We concluded there that the broadest reasonable
interpretation of the phrase “lateral, trans-psoas path to
the lumbar spine” was “an approach to the lumbar spine
that (1) approaches from the patient’s lateral aspect; and
(2) goes through the psoas muscle.” 693 F. App’x at 900–
901.
NUVASIVE, INC. v. IANCU                                   17



    In light of the similarities between the ’767 and ’057
patents, 5 and because the parties agree that the appro-
priate construction of “lateral, trans-psoas path to the
targeted lumbar spinal disc” is that which we enumerated
for “lateral, trans-psoas path to the lumbar spine” in
NuVasive I, we adopt that construction here. See Oral
Arg. 1:33–2:00, 3:57–4:19; Intervenor Br. at 33. We
review the Board’s obviousness decision in accordance
with that construction below.
                             D
     Because this new construction is directly implicated
in the Board’s analysis of secondary considerations, we
address this issue next. The Board concluded that NuVa-
sive’s evidence of secondary considerations was unpersua-
sive because NuVasive had failed to establish a nexus
between the claimed invention and the XLIF surgical
technique. The Board provided two separate grounds for
its conclusion.
    Under the first ground, the Board concluded that the
XLIF procedure was not reasonably commensurate to the
scope of the claims because the claims broadly covered a
“lateral, trans-psoas path” that “encompasses a path to



    5   The ’057 and ’767 patents both disclose a surgical
access system that includes a tissue distraction assembly,
a tissue retraction assembly, and nerve-monitoring. ’057
patent, abstract; ’767 patent, abstract. They also share
many similar specification passages as well as figures.
Compare ’057 Patent, Figures 2–5 and 16–18 with ’767
Patent, Figures 9–12 and 20–22. The fields of invention
in both patents are identical, the discussion of the prior
art is substantially similar, and the surgical systems and
related methods described in the preferred embodiments
are likewise substantially similar. See ’057 patent col. 1 l.
30–col. 2 l. 57; ’676 patent col. 1 34–col. 2 l. 60.
18                                    NUVASIVE, INC. v. IANCU




the lumbar spinal disc, which passes through any portion
of the psoas muscle, regardless of the portion, and which
is to the lateral side of the body, to any significant degree,
as compared to an anterior puncture.” J.A. 10, 20. On
appeal, the PTO acknowledged that that this particular
finding might be in error after our construction of the
term in NuVasive I. Intervenor’s Br. at 47. And we find it
to be in error because the Board’s construction is broader
than that which we adopt in this opinion.
    Second, the Board found that the record NuVasive
produced contained insufficient evidence to demonstrate
whether its XLIF surgical technique is, in fact, what the
’057 patent claims. Characterizing the evidence as “nebu-
lous,” the PTO argues on appeal that the XLIF Surgical
Technique Guide (Guide) NuVasive submitted uses the
XLIF tradename at times in a manner that excludes
limitations of the ’057 patent claims. For example, the
Guide depicts dilators but does specify that these dilators
are part of the XLIF instrument system; rather, these
dilators are part of the MaXcess® II System. J.A. 2636.
And the guide does not consistently identify nerve-
monitoring as a component of the XLIF system. J.A.
2638. Rather, the NeuroVision® System appears to be a
standalone nerve-monitoring product that can be used
with XLIF. Id. We disagree.
    After reviewing the Guide, we conclude that there is a
nexus between the claimed invention and the XLIF surgi-
cal technique. The Board and PTO suggest that only
surgical tools and techniques labeled with the XLIF
tradename are part of the XLIF surgical technique. But
the Guide reveals otherwise. The Guide describes the
“XLIF® technique” as utilizing “a direct lateral, retroperi-
toneal approach to access the intervetebral disc without
muscular disruption or trauma to nearby structures.”
J.A. 2631. It does not describe any other surgical proce-
dures. And the Guide specifically identifies the MaXcess®
II Access System, MaXcess® XLIF System, and Neuro-
NUVASIVE, INC. v. IANCU                                    19



Vision® System as part of the required instruments to
successfully complete the technique. J.A. 2639 (“To
successfully complete this technique, the following in-
struments are required: Radiolucent bendable surgical
table, C-Arm, Light source, MaXcess® II Access System,
MaXcess XLIF® System, Triad® General Instrument Tray,
and NeuroVision® JJB System.”). While the Guide does
list the components of the “XLIF Instrument System,” it
is very clear that the actual XLIF surgical technique
requires more than just these instruments; it utilizes the
MaXcess® II Access, MaXcess® XLIF, and NeuroVision®
Systems in addition to general surgical tools such as
nerve retractors, disc cutters, and curettes that are tradi-
tionally employed in interbody fusion procedures. J.A.
2633.
    At oral argument the PTO argued that the Board
found insufficient nexus due to the “overlapping nature of
the products in the field.” Oral Arg. at 29:13–29:18. The
’057 patent covers method claims whereas NuVasive’s
XLIF-related products cover methods, devices, and sys-
tems. Id. at 29:18–29:31. While we agree with this
characterization, it does not speak to whether the scope of
the claimed invention is reasonably commensurate with
the XLIF surgical technique. Due to the various devices
and systems used in the XLIF procedure such as the
MaXcess® II Access, MaXcess® XLIF, and NeuroVision®
Systems, it is possible that the commercial success evi-
dence NuVasive presented did not come entirely from the
XLIF surgical technique but rather also from the sales of
these devices/systems for use in other surgical procedures.
However, this does not mean that there is no nexus
between the claimed invention and the XLIF surgical
procedure.
    Moreover, “[w]hen the patentee has presented undis-
puted evidence that its product is the invention disclosed
in the challenged claims, it is error for the Board to find to
the contrary without further explanation.” PPC Broad-
20                                  NUVASIVE, INC. v. IANCU




band, Inc. v. Corning Optical Communications RF, 815
F.3d 734, 747 (Fed. Cir. 2016). Here, while the Board did
provide further explanation in finding the evidence
NuVasive produced too nebulous to associate NuVasive’s
objective evidence of nonobviousness with the XLIF
surgical technique, we find this explanation unpersuasive.
As explained above, we find that the Guide clearly lays
out the devices and systems used in the XLIF surgical
technique, some of which are not necessarily labeled with
the XLIF tradename but are nonetheless utilized in the
surgical technique.
     On remand, the Board should reevaluate NuVasive’s
objective evidence of nonobviousness such as long-felt
need, skepticism followed by praise and recognition, and
commercial success under our finding that there is a
nexus between the claimed invention and the XLIF surgi-
cal technique. Our nexus finding, of course, does not
mean that these secondary considerations require a
finding of nonobviousness. We simply require the Board
to evaluate these secondary considerations when consider-
ing the obviousness inquiry as a whole. Further, we note
that “evidence that widespread efforts by ordinarily
skilled artisans had failed” is not necessarily required to
show long-felt need. Millennium Pharm. Inc. v. Sandoz,
Inc., 862 F.3d 1356, 1369 n. 5 (Fed. Cir. 2017) (“Although
‘[e]vidence is particularly probative of obviousness when
it demonstrates both that a demand existed for the
patented invention, and that others tried but failed to
satisfy that demand,’ a patent owner may establish a
long-felt need without presenting evidence of failure of
others.”) (quoting In re Cyclobenzaprine Hydrochloride
Extended-Release Capsule Patent Litig., 676 F.3d 1063,
1082 (Fed. Cir. 2012)). And we also note that the Board
should not dismiss the testimony of paid experts. While
the Board can and should weigh the credibility of any
expert testimony, it should not outright disregard expert
testimony from a witness simply because that individual
NUVASIVE, INC. v. IANCU                                 21



is compensated for his time and expense in testifying.
Nothing in our opinion in InTouch Techs., Inc. v. VGo
Communications, Inc., cited in the Board’s decision,
stands for the proposition that paid expert testimony
cannot be used to establish nonobviousness. 751 F.3d
1327, 1352 (Fed. Cir. 2014).
                            E
    Finally, we address the Board’s analysis of the scope
of the prior art and motivation to combine Kossmann,
Branch, Koros, and Kelleher to arrive at the claimed
invention in the ’057 patent. NuVasive makes two prima-
ry challenges to the Board’s obviousness analysis on
appeal. First, NuVasive argues that there is no motiva-
tion to combine the surgery of Kossmann with the surgi-
cal tools of Branch and Koros.        Second, NuVasive
contends that there is no motivation to use the EMG
nerve-monitoring technology taught in Kelleher during a
lateral, trans-psoas surgical approach to the lumbar
spine. We address each argument in turn.
     As an initial matter, we note that the Board’s overly
broad construction of the term “lateral, trans-psoas path
to the targeted lumbar spinal disc” did not disturb its
motivation to combine the prior art references analysis.
In NuVasive I, the primary dispute between the parties
centered on the meaning of the word “lateral.” 693 F.
App’x at 898. The specification of the patent in that case
distinguished the “lateral” approach from the “postero-
lateral” and “antero-lateral” approaches. ’767 patent col.
7 ll. 43–51. And all nine figures in the ’767 patent show-
ing a path from the surgical incision to the spine depicted
what amounts to a “3 o’clock or 9 o’clock approach to the
spine—essentially along a line 90° to a plane defined by
the (roughly parallel) front-of-body midline and the
spine,” which is much more restrictive than the Board’s
interpretation that covered any approach “lateral, to any
degree, as compared to an anterior puncture.” 693 F.
22                                   NUVASIVE, INC. v. IANCU




App’x at 899 (citing the ’767 patent, Figs. 1, 9–10, 12–15,
and 17–18). Accordingly, we concluded in NuVasive I that
the broadest reasonable interpretation of “lateral” was an
“approach to the lumbar spine that (1) approaches from
the patient’s lateral aspect (or side); and (2) goes through
the psoas muscle.” Id. at 900–901. Here, it is undisputed
that Kossmann teaches a lateral approach to the spine.
J.A. 12634 (Figure 1G), J.A. 12635. Moreover, when
asked at oral argument, NuVasive’s attorney did not
identify any part of the obviousness analysis other than
objective evidence of nonobviousness analysis that relied
on the Board’s overly broad construction of “lateral, trans-
psoas path to the targeted lumbar spinal disc.” Oral Arg.
at 5:50–6:55.
              1. Kossmann, Branch, and Koros
    With this in mind, we do not find that the Board erred
in concluding that a skilled artisan would be motivated to
combine the surgery described in Kossmann with the tools
described in Branch and Koros. NuVasive argues on
appeal that Kossmann does not teach a trans-psoas
surgical approach using retractors and dilators. Rather,
NuVasive posits that Kossmann teaches retracting the
psoas muscle in most patients and only uses blunt dissec-
tion with a surgeon’s finger or a sponge on a stick to
create a path through the psoas muscle in very athletic
patients. As a result, NuVasive argues that a skilled
artisan would not have been motivated to modify the
blunt dissection techniques in Kossmann with the dilation
and retraction technique disclosed in Branch because
blunt dissection is safer for patients. During blunt dissec-
tion, a surgeon carefully feels for nerves and can easily
back off when near a nerve. Blunt dissection also splits
the muscle along its fibers, thus ensuring that no muscle
fibers are cut in the process of dissection. In NuVasive’s
view, this technique is not interchangeable with the
dilator-retractor approach taught in Branch because a
NUVASIVE, INC. v. IANCU                                    23



dilator is a hollow tube that cuts through fibers as it is
pushed through muscle.
     While NuVasive’s argument is not meritless, the
Board’s finding that a skilled artisan would have been
motivated to combine Kossmann with Branch and Koros
is supported by substantial evidence. Dilators and retrac-
tors are ubiquitous surgical tools that skilled artisans
knew how to use to penetrate tissue. J.A. 435–438. We
are not persuaded that these instruments are inherently
less safe means for dissection than a surgeon’s finger or a
wet sponge on a stick, particularly when the skilled
artisan also simultaneously employs nerve-monitoring
technology. Instead, the Board’s finding to the contrary is
reasonable in light of Dr. Lieberman’s testimony that
“[t]he use of instruments such as dilation and retraction
assemblies is no more invasive than the use of blunt
dissection, both techniques do the exact same thing for
the exact same purpose.” J.A. 435. Further, Branch itself
teaches a technique that uses sequential dilators to slowly
increase the size of a surgical site, and it teaches that this
technique is broadly applicable in the field of spinal
surgery. This, the PTO argued, is precisely what a sur-
geon’s finger or a sponge on a stick accomplishes.
    NuVasive also argues that the Board failed to demon-
strate why a skilled artisan would be motivated to modify
Branch’s retractor to incorporate a fixation element as
taught in Koros. According to NuVasive, Koros discloses
a retractor with protruding screws that are specifically
designed for an anterior surgical approach and cannot be
used along a “lateral, trans-psoas path” without signifi-
cant redesign. See J.A. 4547. We do not find NuVasive’s
argument persuasive. Our case law does not require that
the Board explain exactly how the fixation elements of
Koros physically incorporate into Branch’s retractor. We
agree with the Board that a skilled artisan would have
recognized the stability and support the fixation element
in Koros could add to the retractor assembly taught in
24                                  NUVASIVE, INC. v. IANCU




Branch. “[I]f a technique has been used to improve one
device, and a person of ordinary skill in the art would
recognize that it would improve similar devices in the
same way, using the technique is obvious unless its actual
application is beyond his or her skill.” KSR, 550 U.S. at
417. NuVasive has not shown why adding a fixation
element to Branch would be beyond the abilities of a
skilled artisan. NuVasive’s expert testimony regarding
the inoperability of the combination of Branch and Koros
is mere speculation and conclusory. Accordingly, the
Board’s finding that a skilled artisan would have been
motivated to combine Kossmann, Branch, and Koros is
supported by substantial evidence.
                 2. Kossmann and Kelleher
    Next, as to whether a skilled artisan would be moti-
vated to use the EMG nerve-monitoring technology taught
in Kelleher during a lateral trans-psoas surgery, we
remand this issue to the Board for the parties to address
whether Kelleher could be used to monitor the presence of
the iliohypogastric and ilioinguinal nerves. We empha-
size that the scope of this remand on motivation to com-
bine references is for the parties to address this narrow
question. NuVasive asserts on appeal that a skilled
artisan would not use the EMG nerve-monitoring taught
in Kelleher in the Kossmann procedure because: (1)
Kossmann teaches an approach to the lumbar spine
through the anterior-most fibers of the psoas, which is a
“safe zone” where the important structures of the lumbar
plexus do not typically reside, and for which visual detec-
tion of nerves is adequate; and (2) Kelleher does not teach
that its nerve-monitoring technology can be used for
detecting the iliohypogastric and ilioinguinal nerves
Kossmann teaches to avoid.
   We disagree with NuVasive that a skilled artisan
would not be motivated to use neuromonitoring in the
Kossmann procedure. Both Kossmann and Branch teach
NUVASIVE, INC. v. IANCU                                  25



the desirability of avoiding nerves for patient safety.
Moreover, the ’057 patent does not require that the trans-
psoas approach go through a specific part of the psoas,
such as the lumbar plexus. Simply because surgeons
could perform the procedure described in Kossmann with
visual detection alone does not mean that a skilled arti-
san would not be motivated to use neuromonitoring to
further ensure patient safety.
     However, we conclude that the Board’s position that a
skilled artisan would be motivated to use Kelleher’s
nerve-monitoring technique to detect the presence of the
iliohypogastric and ilioinguinal nerves should be remand-
ed for further development. The Board’s original ra-
tionale was that nerve-monitoring in general would be
beneficial in spinal surgeries due to the need to avoid
nerves, and thus a skilled artisan would be motivated to
use Kelleher’s nerve-monitoring technique in Kossmann,
even if Kossmann does not traverse the lumbar plexus.
J.A. 962–63. In its Request to Reopen Prosecution,
NuVasive argued that Kossmann does not mention any
danger of encountering nerves when splitting the psoas
muscle. J.A. 1064. The two nerves Kossmann mentions,
the iliohypogastric and ilioinguinal nerves, do not reside
within the psoas muscle but rather are nerves that lie in
the vicinity of the abdomen. Id. In response to this, the
Board acknowledged in its second decision that the ili-
ohypogastric and ilioinguinal nerves are not located in the
psoas muscle, but noted that they are both still part of the
lumbar plexus, which is what the trans-psoas approach
taught in the ’057 patent seeks to avoid. J.A. 12 n. 4.
Thus, the Board found it “of no moment that the nerves
sought to be avoided in Kossmann are the iliohypogastric
and ilioinguinal nerves[;] these are still nerves that
Kossmann teaches should be avoided in a lateral ap-
proach, which includes the approach taught by Kossmann
that involves splitting the psoas muscle.” J.A. 12. The
Board’s second decision thus appears to rest on a specific
26                                   NUVASIVE, INC. v. IANCU




theory: that a skilled artisan would be motivated to use
Kelleher’s nerve-monitoring technology to detect the
presence of the iliohypogastric and ilioinguinal nerves.
     On appeal to us, NuVasive argues that Kelleher’s
EMG nerve-monitoring method is ineffective for monitor-
ing these two nerves because these nerves do not supply
motor neurons to the legs. The iliohypogastric and ili-
oinguinal nerves supply sensory neurons to the leg and
pubic region and motor neurons to the internal and trans-
verse abdominal muscles. J.A. 2503–2504. EMG, the
nerve-monitoring technique taught in Kelleher, relies on
the detection of motor neurons, not sensory neurons, and
Kelleher teaches that the relevant muscles for nerve
detection in lumbar spinal surgery are those in a patient’s
legs. J.A. 10200, 10215. Thus, according to NuVasive,
Kelleher does not teach that the iliohypogastric and
ilioinguinal nerves are among those that may be detected
with EMG nerve-monitoring technology. The PTO does
not directly respond to this argument. It generally as-
serts that nerves in the psoas muscle are no different
from other nerves in the body and that surgeons would
have viewed existing nerve-monitoring technology as
appropriate for a lateral, trans-psoas approach.
    While we understand the PTO’s position that the
Board was only responding to NuVasive’s arguments
regarding the iliohypogastric and ilioinguinal nerves in its
second decision, the question of whether Kelleher’s nerve-
monitoring technique is applicable to the iliohypogastric
and ilioinguinal nerves is a new finding that NuVasive
has not had an adequate opportunity to address in the
midst of this ever-evolving proceeding. Accordingly, we
remand this very narrow issue to the Board. We also note
that there is nothing in our opinion precluding the Board
from returning to its original position—a finding that we
do not review in this appeal—that a skilled artisan would
have been motivated to use Kelleher’s nerve-monitoring
technique in Kossmann’s lateral, trans-psoas procedure
NUVASIVE, INC. v. IANCU                                27



because Kossmann generally teaches that it is desirable
to avoid nerves during surgical procedures.
                          CONCLUSION
     We have considered NuVasive’s remaining arguments
and find them unpersuasive. We modify the Board’s
claim construction of “lateral, trans-psoas path to the
targeted lumbar spinal disc” and construe the term in
accordance with our opinion in NuVasive I. We reverse
the Board’s finding of a lack of nexus between the method
claimed in the ’057 patent and NuVasive’s XLIF surgical
technique and remand for the Board to conduct a new
analysis of secondary considerations consistent with our
nexus finding. And we affirm the Board’s remaining
obviousness analysis except for its finding that a skilled
artisan would have been motivated to use the nerve-
monitoring technique taught in Kelleher to detect the
iliohypogastric and ilioinguinal nerves. We remand this
narrow issue pertaining to the motivation to combine
Kossmann, Branch, and Koros with Kelleher to the Board
for further consideration.
 AFFIRMED-IN-PART, REVERSED-IN-PART, AND
               REMANDED
                            COSTS
    No costs.
