Coding Question of the Month

January 2019: CPT Code 58661 and Modifier 50

QUESTION: We recently have begun to see denials when billing 58661 with the -50 modifier. The Medicare Fee Bilateral Indicator shows this code allowable with a -50 modifier; however, a few of our payers are citing CPT Assist as their resource for upholding their denial. What is ACOG's position on this code, unilateral or bilateral?


The ACOG Committee on Health Economics and Coding considers CPT code 58661 (Laparoscopy, surgical; with removal of adnexal structures) as a unilateral code.  This was based on a review of the original vignette (developed by ACOG) and the resulting RVU valuation. This code wasn’t valued as a bilateral procedure and should be used with modifier 50.

Per ACOG, modifier 50 should not be used if the code description indicates:

  • The procedure is bilateral. For example, code 58565 reads: Hysteroscopy, surgical; with bilateral fallopian tube cannulation to induce occlusion by placement of permanent implants. 
  • The service can be performed either bilaterally or unilaterally. For example, code 58800 reads: Drainage of ovarian cyst(s), unilateral or bilateral, separate procedure); vaginal approach. 

Sometimes the same procedure is done on two identical organs at the same operative session (e.g., on both the right and left fallopian tube). When this is the case, the bilateral modifier 50 is used.

Modifier 50 should be used if:

The procedure is almost always performed unilaterally but, in this instance, was performed bilaterally. For example, the following codes are considered unilateral per ACOG:

  • 38760/38765, Inguinofemoral lymphadenectomy, superficial
  • 38770, Pelvic lymphadenectomy, including external iliac, hypogastric, and obturator nodes
  • 58345, Transcervical introduction of fallopian tube catheter for diagnosis and/or re-establishing patency (any method), with or without hysterosalpingography
  • 58661, Laparoscopy with removal of andexal structures (partial or total oophorectomy and/or salpingectomy
  • 58672, Fimbrioplasty (laparoscopic)
  • 58673, Salpingostomy (laparoscopic)
  • 58750, Tubotubal anastomosis
  • 58752, Tubouterine implantation
  • 58760, Fimbrioplasty (open procedure)
  • 58770, Salpingostomy (open procedure)

As you can see, per ACOG, code 58661 is one of the codes that should be used with modifier 50. There are no words “bilateral” or “unilateral” in the code description. Hence, modifier 50 should be applied.



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Donna Tyler
Director, Coding

Ipsita Salim
Coding Education Specialist

Miroslava Rudneva
Coding Education Specialist

Tatyana Mallory
Facility Coding Education Specialist


American College of Obstetricians and Gynecologists
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