Accel-KKR has made a majority equity investment in Surgical Information Systems (SIS), according to a news release....By: McGuireWoods LLP. : Accel-KKR has made a majority equity investment in Surgical Information Systems (SIS), according to a news release. SIS, based in Alpharetta, Ga., provides business office management, clinical documentation and patient communications tools for ambulatory surgery centers and anesthesia information management systems and perioperative solutions to hospitals and outpatient surgery departments. Accel-KKR, based in Menlo Park, Calif., is a technology-focused private equity firm.