The Patent Trial and Appeal Board will run a gauntlet of appellate challenges over the next month to its fundamental structure and even its very existence.

Based on arguments Thursday at the U.S. Court of Appeals for the Federal Circuit, the PTAB is likely to pass its first test. But higher-stakes challenges loom tomorrow and next month at the Fourth Circuit.

Johnson & Johnson IP chief Philip Johnson argued the first challenge as part of a battle between health care giants over a surgical stapler that generated $1 billion in sales in three years. The PTAB invalidated a Johnson & Johnson subsidiary's patent on the stapler as obvious last year.