An attorney said Wednesday that a settlement has been reached in a lawsuit filed after a 20-year-old Tonganoxie High School graduate suffered brain damage during a 2009 dental procedure in Lawrence.

“The matter has been settled with all parties, and the case will be dismissed,” said Rick Merker, an Overland Park attorney who represents Dr. Kirk Vincent, a Lawrence oral surgeon.

A hearing is scheduled for 3 p.m. next Wednesday, April 13, during which the parties will ask Douglas County Chief District Judge Robert Fairchild to dismiss the case.

The lawsuit was filed in 2010 on behalf of Austin Stone and his guardians alleging oxygen and nitrous oxide lines were crossed during the design and construction of Vincent’s new office at 4811 Bob Billings Parkway.

Stone had visited the office to get four wisdom teeth removed by Vincent on March 30, 2009, but the lawsuit alleged he was injured and had to be hospitalized. Stone was in a coma after the incident, and he is now legally blind and has other health issues, according to court records and past testimony in the case.

Fairchild in January approved a $3 million settlement in the case between Stone’s family and Action Plumbing Inc. of Lawrence, which denied liability as part of the agreement. The plumbing company installed medical gas lines at Vincent’s new office.

But several others, including Vincent and the city of Lawrence, remained as defendants in the lawsuit. The parties met with a mediator March 23, which led to the settlement, Merker said.

“We had a very, very lengthy, very hard mediation session in this case,” he said.

Merker said the amount of the settlement for private entities involved would remain confidential as part of the agreement.

Lawrence attorney Jerry Cooley, who represents the city, said Wednesday he could not comment about the settlement until it had a judge’s approval. The city was included as a defendant because the lawsuit alleged inspectors should have caught the switch in the lines.

Other than the city and Vincent, remaining defendants are Patterson Dental Supply Inc. of Topeka; Blanchard Design Group LLC of Lawrence, the project’s architect; general contractor Design Build Collaborative LLC of Lawrence; and mechanical engineers Hoss & Brown Inc. of Lawrence.