About Mark R. DeHaan, MD Dr. DeHaan attended medical school in his native Chicago, eventually completing a plastic surgery residency in Grand Rapids. He specializes in hand, upper extremity and microsurgery and has lectured and written extensively on the subject of occupational injuries and the surgical management of carpal tunnel syndrome. He has special training and experience in endoscopic carpal tunnel release surgery and post traumatic reconstructive hand surgery. About OAM Hand & Upper Extremity Center Every day, technology advancements help the doctors and clinical specialists of the OAM Hand and Upper Extremity Center get patients back to their normal routines more quickly, with reduced pain and increased function.