A surgical apparatus placed “in proximity to … [a] first vertebral bone” did not give sufficient notice of the degree of proximity that would infringe the claim in Abdou v. Alphatic Spine, Inc. The liberal pre-Nautilus test for definiteness (35 USC 112) – that a patent claim need only not be “insolubly ambiguous” – was satisfied, but not the Supreme Court’s new, more rigorous Section 112 test under Nautilus v. Biosig Instruments, Inc. The district court in Abdou concluded that the claim failed this test because “in proximity to” did not “inform, with reasonable certainty, those skilled in the art about the scope of the invention.” What distance qualifies as being in proximity to and thus within the claim’s scope? What distance does not? The Abdou court found that one of ordinary skill (a surgeon) reading the patent would not have known. According to the court there were no identified boundaries that could be gleaned from the specification. The patent was therefore found invalid as indefinite.

The Abdou decision suggests that a term of approximation, such as “in proximity to,” “about,” and “substantially,” appearing in a claim and not being explained in the specification will not give the notice of claim scope required under the Nautilus test for indefiniteness. These terms, generally speaking, have meaning and boundaries capable of being found. This is not however good enough. More certainty of a claim’s boundaries is needed under Nautilus. At least according to this district court, claims limited by terms of approximation not explained in the specification do not pass the test. I wonder if this is a sign of things to come.

It perhaps should not come as any surprise to patent prosecutors that claims limited by terms of approximation not explained in the specification are becoming more and more suspect following the Nautilus decision. The U.S. Patent & Trademark Office is now routinely rejecting applications that use such terms in claims. Consider adding definitions or examples explaining the scope of a term of approximation, or don’t use these kinds of words in patent claims.