Modifier 78 – Unplanned return to the operating room by the same physician following the initial procedure for a related procedure during the postoperative period

The following rules apply:

•    Apply modifier 78 to unplanned or unanticipated surgical procedures that are performed to treat postoperative complications from the original surgery. Some examples of postoperative complications include excessive bleeding or infection.
•    The unplanned surgery always involves a separate operative session than the original surgery.
•    The unplanned surgery does not restart or begin a new global period.
•    Modifier 78 is not used to  report a repeat of the same procedure during the same operative session.
•    If modifier 78 isreported with assistant surgeon modifiers (80, 81, 82, and AS), list the assistant surgeon modifier first.
•    Do not report with modfiers 58 or 79.
•    Modifier 78 is a payment modifier. Procedures are reimbursed for the  intraoperative portion of the procedure (70 or 80 percent of the physician fee schedule for the surgical procedure).

Example
On April 1, a patient undergoes knee replacement arthoplasty (27440) on her right knee. The patient ends up with a severe knee joint infection. On April 30, the surgeon performs a knee arthrotomy (27310). Since the knee arthrotomy was performed less than 90 days after the original procedure, the procedure is reported as 27310-78-RT.