Justice Neil Gorsuch asked about severing Section 6(c) of the Patent Act, 35 U.S.C.A. § 6(c), which gives the PTAB exclusive rights to rehearings. Lamken, however, insisted this "wouldn't even fix the problem," because the director's part would still be limited.

Mark A. Perry of Gibson, Dunn & Crutcher LLP argued for Smith & Nephew. Principal officers are those whom the Supreme Court has recognized as "the ambassadors and the cabinet officers, and the heads of agencies," not those who preside over patent disputes, he said.

Justice Elena Kagan asked how the USPTO could call its officers "inferior" when they make decisions with little accountability.

Justice Gorsuch posed a similar question: "Is it fair to say that, yes, this is a rare bird … in the sense that there isn't final review in the agency head?"

"It is unusual, but it is also well and historically founded and … until now, unchallenged," Perry answered, noting a 150-year-old "patent-specific tradition."

Attorneys not involved in the case offered their predictions of how the dispute will turn out based on the justices' questions during the oral argument.

Darius Gambino, a partner at Saul Ewing Arnstein & Lehr LLP, said he expects the Supreme Court to find a way to save the PTAB by adding director oversight.

"The USPTO has always had the power and authority to adjudicate patent validity issues, both pre-grant and post-grant, and the PTAB is really no different in that regard," he said.

Blair Silver, an attorney with Banner Witcoff, said the justices appeared to find the appointment of APJs to be unconstitutional, but "they seemed wary of the drastic remedy sought by Arthrex of dismantling the [PTAB] and overturning the current system."

"The court may be poised to strike portions of the statute in a surgical manner by giving the USPTO director authority to directly review decisions of the APJ panels," he said.

Aziz Burgy, a patent attorney at Axinn, Veltrop & Harkrider LLP, also said the majority of justices appeared to view APJs as principal officers given their authority and lack of accountability.

"Even though the odds favor a finding that APJs are principal officers, it is unlikely the court will throw out the entire PTAB scheme with the bathwater," he said. "Instead, the substance and tenor of the questions seem to suggest that the court will attempt to fix the problem by 'blue-penciling' the statute by perhaps requiring additional oversight over the APJs."

Scott Hejny, an attorney at McKool Smith, said the Supreme Court could still maintain a strict reading of the Patent Act and not have the PTO's director review PTAB decisions, but this would require Congress to fix the issue and "could take time."

"The easiest paths for the Supreme Court are to either overturn the Federal Circuit decision, finding that the PTAB structure truly is a 'rare' — but constitutional — bird, or affirm the Federal Circuit decision."

George E. Quillin of Foley & Lardner LLP said "a decision with the least immediate impact would be one in which the court agrees with the government and Smith & Nephew that administrative patent judges have been inferior officers all along."

"Hence, there would be no need for a judicial fix to anything," he said.

Donald Falk, a partner in Mayer Brown's Supreme Court & Appellate and Intellectual Property practices, said that the final holding, which is due by the end of June, will probably include several opinions by a divided court.

"One can only hope that there is a firm majority that can provide clear instructions on how to fix the statute (in the case of an affirmance) or how to keep future administrative adjudicatory systems within constitutional limits (in the case of a reversal)," he said.