Addressing whether the Patent and Trial Appeal Board (PTAB) relied on the same articulated reasoning and factual underpinnings as did the examiner in finally rejecting application claims, the U.S. Court of Appeals for the Federal Circuit vacated and remanded a decision by the PTAB, finding that the PTAB relied on a new ground of rejection.  In re Lutz Biedermann, Case No. 13-1080 (Fed. Cir., Oct. 18, 2013) (Linn, J.).

The instant application was directed, in part, to a bone screw having a locking element or screw with a square thread used to secure a rod.  In rejecting claims, the examiner cited a primary reference, Cotrel, which disclosed a bone screw having a locking element or screw, and a rod, and a secondary reference, Steinbock, which disclosed a screw with a square thread.  The examiner reasoned that it would be obvious to combine the square thread of Steinbock with the device of Cotrel, because Steinbock teaches that a square thread is most efficient for load transfer.  Biedermann argued that Steinbock taught against the use of a square thread.  The passage of Steinbock referred to by Biedermann recites “[t]he square thread is generally regarded as most efficient, but is difficult to cut because the thread form provides parallel sides.  It also cannot be adjusted to compensate for wear.  The Acme form of thread does not suffer from the disadvantages of the square thread form, it is stronger and only slightly less efficient.”

On appeal, the PTAB concluded that the combination of Cotrel and Steinbock made the application claims obvious because Cotrel taught avoiding splaying with saw-tooth threads and that saw-tooth threads are buttress threads.  Also, the PTAB concluded that Steinbock groups square threads and buttress threads together and that square threads also are used to avoid splaying. The PTAB stated that Steinbock’s treatment of the various thread forms suggests their interchangeability.  Finally, the PTAB cited a new reference, the Machinery’s Handbook, to support its findings.

Biedermann requested a rehearing arguing that the switch from an argument based on “efficiency” to one of “interchangeability” and the addition of a new reference constituted a new ground of rejection.  The PTAB denied the request, stating that it merely provided a more detailed rationale for the examiner’s rejection in its response to Biedermann’s arguments.  Further, the PTAB stated that the use of Machinery’s Handbook was simply as a technical dictionary.  Biedermann appealed to the Federal Circuit.

On appeal, the Federal Circuit found that the thrust of the rejection changed when the PTAB articulated a new factual basis for combining Cotrel and Steinbock.  The Federal Circuit found that when the PTAB changed the basis for the combination of prior art references, notwithstanding that it was responding to an appellant’s argument, the PTAB went beyond merely filling in gaps in the examiner’s reasoning and created a new ground of rejection. 

Further, the Federal Circuit found that the PTAB citation to the Machinery’s Handbook to associate buttress and saw-tooth threads supported only the PTAB’s position, not the examiner’s position (since the examiner’s reasoning was not concerned with any association between the two thread types) which additionally demonstrated the new ground of rejection.