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Modifier 51 or 59? How to correctly report multiple procedures

The correct use of modifiers 51 and 59 are explained, including case examples featuring clinical scenarios with correct coding.

Jayme Lieberman, MD, FACS, Megan McNally, MD, FACS, Jan Nagle, MS

April 1, 2019

Modifiers enable surgeons to effectively meet payment policy requirements established by the Centers for Medicare & Medicaid Services (CMS) and other third-party payors. However, there continues to be confusion about when to report modifier 51 (Multiple procedures) or modifier 59 (Distinct procedural service) when the same surgeon performs multiple procedures in the same operative setting. This column reviews the correct use of modifiers 51 and 59.

Until 1996, multiple procedures were reported with modifier 51 appended to the second and subsequent American Medical Association (AMA) Current Procedural Terminology (CPT*) codes. In 1996, CMS implemented the National Correct Coding Initiative (NCCI) to control improper unbundling of codes for Medicare Part B services. These edits, which are updated annually, are based on coding conventions defined in the AMA CPT codebook, national and local payor policies, coding guidelines developed by national societies, and standard medical and surgical practices.

The NCCI Coding Policy Manual includes procedure-to-procedure (PTP) edits that define when two codes should not be reported together for the same operative session. The PTP edits have a Correct Coding Modifier Indicator (CCMI) assigned to each code pair as follows:

  • A CCMI of “0” indicates the codes should never be reported together by the same provider for the same beneficiary on the same date of service. If they are reported on the same date of service, the column one code is eligible for payment, and the column two code will be denied.
  • A CCMI of “1” indicates the codes may be reported together in defined circumstances, which are identified on the claim by the use of specific NCCI-associated modifiers. These modifiers include anatomic modifiers and modifiers for staged (58), repeat (76), and distinct (59) procedures.

In contrast, if there is no NCCI edit for a code pair, then modifier 51 is appended to the additional procedure code(s) with a global period of 000, 010, or 090 when multiple procedures are performed by the same surgeon in the same operative session. Do not append modifier 51 to add-on codes that have a “ZZZ” global assignment. Surgeons can expect to get reimbursed 100 percent for the first procedure and 50 percent for the second through fifth procedures per Medicare’s Multiple Procedure Payment Reduction (MPPR) policy. If more than five different procedures are performed, an operative report will need to be submitted for payment of all the procedures. This situation occurs most frequently when billing for trauma care.

Case examples

Following are some examples of clinical scenarios and correct coding.

Scenario 1

An accident victim undergoes debridement of a wound to the bone on the anterior lower right leg and debridement to the muscle on the posterior thigh of the same leg. Both wound sizes are less than 20 sq cm. The debridement codes 11042 (debridement, muscle) and 11044 (debridement, bone) have a PTP edit because this code pair cannot be reported for debriding the same wound. However, the code pair has a CCMI of “1” in recognition of the fact that the debridements may be performed at separate distinct anatomic sites. Because there is an NCCI edit, these procedures would be reported as: 11044, 11042-59.

Scenario 2

A patient who had previous abdominal surgery presents with a large reducible recurrent incisional hernia. After extensive lysis of adhesions and excision of subcutaneous scar tissue, the incisional hernia is repaired using musculofascial flaps (component separation) and implantation of mesh. No NCCI edits apply to any combination of the procedure codes that will be reported. However, modifier 59 should be appended to the second instance of code 15734 (musculofascial flap) to indicate that it is a distinct and separate service. This operation would be reported as: 15734, 15734-59, 49565 (hernia repair), 49568 (insertion of mesh). Modifier 51 could be appended to 49565; however, most payors suggest not appending modifier 51 to any codes because coding software will automatically adjust payment for multiple procedures. No modifier is appended to code 46568 because it is an add-on service with ZZZ global assignment.

Scenario 3

A patient presents with multiple stab wounds to the abdomen. A laparotomy is performed, and a laceration of the small bowel is repaired. At a different section of the small bowel, the stab wounds required resection and anastomosis. An NCCI edit exists for 44602 (repair laceration of the small bowel) and 44120 (small bowel resection and anastomosis), and therefore, this operation would be reported as: 44602, 44120-59.

Scenario 4

A patient is unable to be liberated from a ventilator after an acute injury. A planned percutaneous tracheostomy (31600) and percutaneous endoscopic gastrostomy (43246) are performed in the same operative setting. Codes 31600 and 43246 do not have an NCCI edit, but the 31600 descriptor states “separate procedure,” and the NCCI manual states to append modifier 59 to the separate procedure code. In this case, it would be acceptable to report 31600-59, 43246-51; however, it also may be unnecessary because it is clear that the two procedures are not in an anatomically related region or through the same skin incision. Use of modifier 59 will be based on payor preference.

Learn more

It is important to keep up to date with changes in coding policies. More information about NCCI edits and the quarterly PTP edit updates are available online.

Learn more about correct coding at an American College of Surgeons (ACS) General Surgery Coding Workshop. Physicians receive up to 6.5 AMA PRA Category 1 Credits™ for each day of participation. Find out more and register for a 2019 workshop on the ACS website.

*All specific references to CPT codes and descriptions are © 2018 American Medical Association. All rights reserved. CPT and CodeManager are registered trademarks of the American Medical Association.