Annette Corinth says doctors removed a needle, compresses and surgical strips from banker Helmut Brecht after his wounds failed to heal properly following surgery in 2009.
The 77-year-old ex-banker died last year and his family is seeking €80,000 ($106,216) damages for his suffering, plus costs, from the Henriettenstift hospital in Hannover.
A spokesman for the Protestant Church-linked organization that runs the hospital rejected the claims.
Achim Balkhoff told The Associated Press Thursday the objects couldn't have been left in the patient's body during the operation because the equipment wasn't in use at the hospital.
He added that the compensation demands were "unusually high" for such a case.