Bilateral Surgery

Bilateral surgeries are procedures performed on both sides of the body during the same operative session or on the same day. Correct bilateral billing will ensure timely and accurate processing of these claims.

Identifying Bilateral Codes

In some cases, descriptors for procedure codes can be included within the description itself.

  • CPT code 27395 has "bilateral" in the description: Lengthening of the hamstring tendon; multiple, bilateral.
  • CPT code 52290 has "unilateral or bilateral" in the description: Cystourethroscopy; with ureteral meatotomy, unilateral or bilateral.

The payment adjustment rules for bilateral surgeries do not apply to procedures identified by the CPT descriptor as "bilateral" or "unilateral or bilateral" since the fee schedule payment amount already reflects any additional work required for bilateral surgeries so described.

The Medicare Physicians Fee Schedule (MPFS) supplemental documents, the "MPFS Indicator Descriptors" and the "MPFS Indicator List", are located on the Noridian "Fee Schedules" webpage. These reveal whether the payment adjustment rules apply to a surgical procedure and how the claim should be billed.

MPFS Indicator "B" - Descriptors

Indicator Description
0 Bilateral surgery rules do not apply. Do not use 50 modifier
1 Bilateral surgery rules apply (150%). Use 50 modifier if bilateral. Units = 1.
2 Bilateral surgery rules do not apply. Already priced as bilateral. Do not use 50 modifier. Units = 1.
3 Bilateral surgery rules do not apply. Do not use 50 modifier. Units = 1 or 2.
9 Bilateral surgery concept does not apply.

 

The bilateral indicator "B" column shows that:

  • CPT 27331 has a bilateral indicator of a 1, which means bilateral surgery rules apply. If the 50 modifier is appended to the CPT with 1 unit billed, Medicare will allow 150%. If billed with 2 units, it states the procedure was completed 4 times and will be denied as unprocessable. If two of the same services were performed bilaterally, the services should be billed on two separate lines with 1 unit apiece, the 50 modifier and the appropriate repeat modifier on one of the lines.
  • CPT 28340 has bilateral indicator of 0. Bilateral surgery rules do not apply and modifier 50 is not to be used.
  • CPT 27395 has a bilateral indicator of a 2, which means bilateral surgery rules do not apply. These procedures are already priced for either a unilateral or bilateral performance. It would be inappropriate to bill the procedure with the 50 modifier as a bilateral service. Also, it would be inappropriate when billed on 2 lines or with 2 units if only one service was performed, even when using an RT and LT modifiers.

Codes with a 2 indicator are already priced at 150% which means Medicare is already paying for both sides. If billed on two lines or with two units the total allowed amount will be 300% instead of 150%. This would be incorrect billing if only one service was performed.

Billing Guidelines

A procedure that is not identified by its descriptor as a bilateral procedure (or unilateral or bilateral), indicates the physician must report the procedure with the 50 modifier. For Medicare billing purposes, such procedures should be reported as a single line item. (Note: This differs from the CPT coding guidelines which indicate that bilateral procedures should be billed as two line items.)

A procedure that is identified by its descriptor as a bilateral procedure (or unilateral or bilateral), as in codes 27395 and 52290 listed above, requires the physician to not report the procedure with the 50 modifier.

Ambulatory Surgical Centers (ASCs) cannot append the 50 modifier on bilateral surgery claims. Bilateral procedures must be reported on two separate lines appending the appropriate RT and/or LT modifier.

Processing Guidelines

We (Noridian) will process claims for bilateral surgeries according to the presence of the 50 modifier on the CMS-1500 claim form, or its electronic submission, or of the same code on separate lines, one line with LT modifier and the other with the RT modifier.

We recommend such surgeries be billed on one line with the 50 modifier. Billing two lines with LT and RT modifiers may cause the claim to deny.

Resources

 

Last Updated Dec 09 , 2023