CAFC Rejects PTAB’s Interpretation of “Lateral, Trans-Psoas Path” in IPR

In In Re: Nuvasive, Inc., the CAFC vacated the PTAB’s Final Decision in an IPR because the PTAB misconstrued the broadest reasonable interpretation of the claim term “lateral, trans-psoas path.”

By way of background, the patent at issue, US 8,016,767, was drawn toward surgical methods for inserting a spinal fusion implant.  During such surgeries, it was known to approach the spine from the front (anterior) of the patient or from the back (posterior) of the patient, both of which are associated with disadvantages.  An approach to the spine from the side of the patient may be able to avoid those disadvantages, but comes with its own drawbacks, namely, the possibility of damaging nerves in the psoas muscle, which runs along the side of the lower spine.  Claim 1 of the ‘767 patent claims a method including the steps of inserting instruments “along a lateral, trans-psoas path,” which is a limitation recited eight times in claim 1.  

Medtronic filed an IPR challenging the claims of the ‘767 patent.  In its final written decision, the PTAB held that “the broadest reasonable construction, consistent with the specification of the ’767 patent, of ‘lateral, trans-psoas path to the lumbar spine,’ encompasses a path, to the lumbar spine, which passes through any portion of the psoas muscle, regardless of the portion, degree, or extent of passage through the psoas, and which is lateral, to any degree, as compared to an anterior puncture.” In reaching this conclusion, the PTAB noted that the specification did not define that word, and the PTAB

relied on the deposition testimony of Dr. Obenchain, the inventor of a prior art reference.  Based on this BRI, the PTAB invalidated the challenged claims as being obvious.  NuVasive appealed to the CAFC, and during briefing, Medtronic withdrew and the Director of the USPTO intervened to defend the Board’s decision.

The CAFC first took issue with the PTAB’s reliance on expert testimony from the inventor of the prior art reference.  The BRI is taken in light of the specification of the patent at issue.  In contrast, the CAFC decided that the line of questioning during the deposition made it clear that the prior art inventor was referring to the term “lateral” in the context of his own patent, which was directed toward a method involving an anterior approach that does not go through the nerve-rich part of the psoas.  Thus, the CAFC held that it was an error for the PTAB to interpret the prior art inventor’s interpretation of “lateral” as establishing how a person of ordinary skill in the art would read “lateral” in the context of the ‘767 patent. 

Further, while the ‘767 patent does not explicitly define “lateral,” the CAFC found that some disclosure of the ‘767 patent was contrary to the expert testimony and indicated that the proper scope of “lateral” is more restrictive that the Board’s interpretation.  

The CAFC concluded:

Indeed, the Board’s construction seemingly drains the term of meaning in the claim phrase. The psoas muscle does not cross the midline, so any approach that traverses the psoas to get to the spine would seem to be “lateral” in the Board’s sense. By claiming a “lateral, trans-psoas approach”—not a “trans-psoas approach” or a “postero-lateral, trans-psoas approach”—NuVasive must be taken to have limited its claim beyond what “transpsoas approach” would cover.

This case is another reminder that the broadest reasonable interpretation is taken in light of the specification of the patent at issue.  In this case, the CAFC held that the evidence relied upon by the PTAB was divorced from the specification.