SAN FRANCISCO — Intuitive Surgical has tapped Skadden, Arps, Slate, Meagher & Flom partner Allen Ruby to fight an effort by Illinois Union Insurance Co. to void a liability policy it issued the medical device maker earlier this year.

Illinois Union accuses Intuitive of concealing the existence of so-called tolling agreements with plaintiffs lawyers that held injury claims at bay while freezing the statute of limitations. Learning of the agreements dramatically changed the insurer’s risk analysis, because it showed claims accelerating more rapidly than other records indicated, the suit asserts.

Intuitive, which makes the da Vinci robotic surgical system, is facing a mounting docket of product liability cases and Ruby has led the company’s defense in many of those suits. Earlier this year, Ruby won a defense verdict in a wrongful death suit tried in Washington. He responded to the insurer’s claims Monday in an answer filed in the Northern District of California.

That same day, New York–based Navigators Specialty Insurance Company filed a similar suit against Intuitive demanding that it also be allowed to drop its policy after learning of the tolling agreements.

“Had plaintiff known during the application and underwriting process for the policy of the existence of the subject tolling agreements and other information documenting the existence of undisclosed claims and the increasing numbers of claimants being added to the tolling agreements, plaintiff never would have issued the policy,” wrote attorneys David McMahon and John Pierce of Barger & Wolen.

Intuitive markets its robotic surgical system as a faster, safer and less invasive method to perform an array of surgical procedures. The device received FDA approval in 2000 and was used in about half a million procedures last year throughout the world. In choosing Ruby, Intuitive has turned to one of Silicon Valley’s most experienced and in-demand litigators. This year, the Palo Alto–based partner, who defended slugger Barry Bonds in his criminal trial, has represented Hewlett-Packard Co. board members in a securities class action in the Northern District of California, and served as lead counsel for ConAgra Grocery Products Co. in a high stakes case against lead paint manufacturers fought this summer in Santa Clara County Superior Court.

Contact the reporter at mtaves@alm.com.