If the subsequent surgery is unrelated to the initial surgery and both are performed by the same surgeon, refer to CPT® modifier 79 If the subsequent surgery is related to the initial surgery but does not require a return to the operating room, and both are performed by the same surgeon...
It mentions that if physicians are seeing a patient in the office following a procedure that has a global period and the patient has a new diagnosis that is unrelated to the procedure, the modifier will protect the service from being bundled into the global surgical package and reimbursement ...