Ex parte Strkyer Endoscopy
Appeal 2009-010003; Appl. No. 10/680,079; Tech. Center 3700
Decided December 22, 2010
This application involved a surgical apparatus for delivering and retrieving a suture. Claim 36 included a cannula (hollow tube for insertion into a body cavity), and the disputed limitation was "wherein a portion of a distal end of the cannula is configured to drive a suture against tissue without severing the suture."
The Examiner rejected claim 36 as being anticipated by Violante, which disclosed a surgical instrument including a hollow needle for delivering suture thread to a body location. According to the Examiner, the needle tip 42 in FIG. 2 corresponds to the "distal end of the cannula is configured to drive a suture against tissue without severing the suture."
Neither FIG. 2 nor any other figure in Violante showed the needle tip in detail. But in the Appeal Brief, the Applicant pointed to the portions of the specification which described the needle tip. These portions described the needle tip as "beveled and sharpened" and "present[ing] a sharpened edge that may be employed in cutting of suture material." The Applicant argued that "the bevel causes the interior surface of the trailing end of the bevel to be sharply acute," which presents "a distinct danger that a suture ... will be severed during insertion." Thus, Violante's needle tip was not "configured to drive a suture ... without severing."
In the Answer, the Examiner responded that Violante met the claim limitation in two ways. First, while the point of the needle tip is sharp, the face of the bevel is blunt. Thus, the face of the bevel is "a portion of the distal end of the cannula" which can be applied to drive the suture "without severing." Furthermore, even the sharp portion of the beveled tip "forms a narrow point that would not likely engage and sever a suture." (Emphasis added.) Since Violante describes the needle as being used for tissue penetration "there is little or no danger that a suture inserted through the use of the device of Violante would be severed during insertion."
The Applicant responded to this last point in the Reply Brief. While acknowledging that a beveled and sharpened tip can penetrate tissue, the Applicant argued that the reference did not disclose "how the suture can be inserted through tissue without being severed by the sharpened edge." According to the Applicant, the reference did not explain how the needle tip actually interacts with the suture during tissue puncturing.
The Board affirmed the anticipation rejection, but seemed to apply a slightly different rationale. The Board agreed with the Examiner that some portions of the needle tip would be incapable of severing the suture. But while the Examiner relied on the face of the bevel as that portion, the Board instead looked to the "side of Violante's tip that is not beveled". That side "remains unmodified and thus retains the curved shape of the cylindrical tube's outer surface." The Board found that this curved portion of Violante's needle tip "would not operate to sever suture when driven against tissue."
The Board then went further to note that Violante's structure actually taught more than was necessary. According to the Board, all that was necessary to satisfy the "broadly written" claim was "a structure that in some circumstances will not sever a suture when pressed or driven against body tissue. "
[C]laim 36, as broadly written, excludes only those structures that would sever a suture in every instance upon being driven against tissue. That a "beveled and sharpened tip" includes a sharpened edge which may be useful in cutting a suture material does not mean that in all circumstances the tip severs the suture material. Indeed, the tip's ability to cut the material is not dependent solely on the tip's configuration but is also a function of other factors such as the driving force applied to the suture, the strength of the material that makes up the suture, and the tension on the suture. Violante's tip, even if
sharpened, may be driven against tissue with a force of inadequate magnitude to severe a particular suture. It is neither unreasonable nor inconsistent with Stryker's specification that the beveled and sharpened tip in Violante constitutes a structure that in some circumstances will not sever a suture when pressed or driven against body tissue. That is sufficient to satisfy claim 36.
My two cents: Was it the presence of "configured to" that led the Board to take such an expansive reading of the claim language? Under the Board's reading, a sharp needle tip meets the limitation as long as the surgeon uses minimal force and/or the suture is made of incredibly strong fiber. Does using purely functional language always result in this sort of interpretation?
To combat this you may need to recite structure that performs this function. In this case, the structure that produced the behavior of "driv[ing] a suture against tissue without severing the suture" was a "blunt heel" (274 in FIG. 42 below).
This feature is very clearly shown in Figures 42 and 43, and is described in the accompanying text of paragraph 222, which reads "[tlhe cannula is preferably blunted or rounded off at 274 (see FIGS. 42 and 43) so as to minimize the possibility of damaging a suture during a tissue piercing operation, as will hereinafter be discussed in further detail." ...
Clearly, the blunt heel 274 is a feature entirely different from and independent of the beveled shape of the cannula tip.
The BPAI ignored this argument, of course
In this case, if Stryker intended that its cannula end includes the specific structural characteristic of a "blunt heel," it could easily have amended the claims accordingly. It did not. Claim 36 requires simply that "a portion of the distal end of said cannula is configured to drive a suture against tissue without severing the suture." That feature is met in the prior art by a cannula or tube having a distal end with any portion of the distal end configured such that it does not sever suture when driven against tissue.
This feature was captured in an originally filed dependent claim. But that claim was canceled before appeal.
The first explanation of how the needle tip in the reference met the limitation didn't appear until the Examiner's Answer.