They can, but ruling on an appeal without issuing an opinion is not only considered bad jurisprudence, it has no precedential effect and thus does not create binding law on the lower court.

Consequently, it is rarely done. Moreover, in most instances where it is done, the reversal is on procedural rather than substantive grounds.

It seems whether the ruling sets a precedent or not is irrelevant, since the Federal Circuit will just ignore it anyway.