Ex parte Shekalim
Appeal 2011009757; Appl. No. 11/885,158; Tech. Center 3700
Decided July 5, 2012
The application was directed to a balloon catheter with an external scraper cord. When the balloon expands, the cord comes into contact with the blood vessel walls. As the balloon is moved along the vessel, the cord scrapes deposits from the vessel walls.
A representative claim on appeal read:
1. Apparatus for removing deposits from a selected location on the inner surface of a tubular structure, comprising:
an expansible device constructed such that in its non-expanded condition, it is introducible into the tubular structure, manipulatable therein to said selected location of the tubular structure, and radially-expansible therein to engage the inner surface of the tubular structure and the deposits to be removed; and
at least one elongated scraper cord carried on the outer surface of said expansible device,
said scraper cord being of a flexibility and a thickness to engage the inner surface of said tubular structure upon the expansion of said expansible device, and
having a circumferentially extending intermediate length axially movable with respect to and along the outer surface of said expansible device in its expanded condition to scrape away said deposits from the inner surface of the tubular structure.
During prosecution, the Examiner rejected an earlier version of claim 1 as as anticipated by the balloon catheter in FIG. 5 of McMurtry (shown below).
The Examiner mapped the "expansible device" element to McMurtry's balloon 14 and the "scraper cord" element to McMurtry's guide wire 15. The Examiner noted that the guide wire was movable along the outer surface in two ways: proximally/distally, through ports 21 and 22; and rotatably, via its proximal end through opening 20 (not shown in FIG. 5).
The Applicant argued that McMurtry's element 15 was not a "scraper cord" but instead was a "guide wire" that acted to guide the catheter into the artery and hold the balloon after expansion. According to the Applicant, McMurtry's guide wire was "certainly not constructed to serve as a 'scraper cord' to scrape away deposits from the inner surface of the artery.
Nevertheless, Applicant amended to further describe the scraper cord as "having a circumferentially extending intermediate portion axially movable." The Applicant then asserted that "such a structure is clearly not present in McMurtry, and to modify it to provide such a structure would render the device of that patent unworkable to perform its intended guiding function."
The Examiner maintained the rejection on final. With respect to the "circumferentially" limitation, the Examiner explained that "since the cord 15 has a thickness/is three dimensional, it extends circumferentially." With respect to the "axially movable" limitation, the Examiner repeated the same comments about proximal/distal movement and rotational movement. Finally, the Examiner found "no structural limitations that distinguish the claimed 'scraper cord' over the cord/guidewire in the McMurtry et al. reference that would deem the cord/guidewire incapable of scraping within a vessel."
The Applicant filed an After Final Response. The Applicant argued that the Examiner's interpretation of the claimed scraper cord was unreasonable, and that the guidewire in the reference was not capable of scraping.
[O]ne skilled in the art would not construe the above-quoted recitation from claim 1 as "reading on" the thickness of the guidewire of McMurtry et al., nor that the guidewire of McMurtry et al. is capable of performing the function of the scraper cord in Applicant's construction, namely to scrape away deposits from the inner surface of the tubular structure. Particularly in this case, where the guidewire is of small circular diameter, both its "circumferentially-extending intermediate portion", which produces the scraping action, and the scraping action produced thereby, would not be significant especially since its movement is constrained to a linear, axial movement.
The Examiner issued an Advisory Action that essentially repeated the earlier assertions.
On appeal, the Applicant made the same arguments: that the Examiner's construction of the claimed structure of the scraper cord was unreasonable; and that the guide wire wasn't capable of the claimed scraping function. The Examiner maintained the same position in the Answer. The Applicant filed a Reply Brief alleging that the Answer "failed to reference Appellant's arguments in the Appeal Brief."
The Board affirmed the anticipation rejection. The Board agreed with the Examiner’s finding that McMurtry’s guide wire had the capabilities of the scraper cord recited in claim 1. More specifically, the Board agreed that since a guide wire does have some thickness, "its width or diameter necessarily extended circumferentially with respect to the balloon’s outer surface." The Board further elaborated on this point:
That is, some portion of the balloon’s circumference is necessarily covered by the width of the guide wire, even if less than a degree of the circumference. McMurtry’s guide wire satisfies the first of the disputed requirements.The Board also addressed the "axially movable" limitation. After first noting that the claim itself didn't specify a reference axis, the Board looked to the specification or drawings. The phrase "axially movable" was not found in the specification, and no annotations were present in the drawings to specify an axis. However, movement along the longitudinal axis of the balloon was illustrated in Applicant's Figs. 1a-c, and this met the ordinary meaning of "axially." Since McMurtry’s guide wire also moved parallel to the longitudinal axis of the balloon, McMurtry taught this limitation.
My two cents: The Applicant's catheter clearly had structure which was distinguishable from McMurtry. Compare McMurtry's guide wire 15 (left) with Applicant's scraper cord 4c (below right):
surrounds a much larger portion of the circumference of the balloon, due to its multiple segments that snake back and forth. In contrast, McMurtry's guide wire 15 covers only an insignificant portion of the circumference of the balloon, though since the guide wire 15 has a width it does cover some of the balloon.
I suspect it was this aspect that the Applicant tried to express through the "circumferentially extending" limitation. But the Applicant's choice of language didn't quite do it for the Examiner or for the Board.
I'm not an expert in drafting mechanical claims, so I won't opine on how best to express this distinction. Maybe you need to at least add in the notion of multiple segments, if "circumferentially" only make sense when there are multiple segments to go around the circumference. Note that this aspect was captured in dependent claim 4. On appeal, dependent claim 4 was rejected as obvious, but The Examiner withdrew this rejection in the Answer.
I will say that the Examiner's interpretation of "circumferentially extending" seems devious to me, but not ridiculous. Maybe the Applicant fully appreciated this yet appealed the independent claim anyway, knowing that claim 4 (which better expressed the distinction) was allowable.