Washington, D.C., Subscriber
Answer: You are correct: There is no CPT code that describes removal of stones from the common duct during a lap chole (47564, Laparoscopy, surgical; chole-cystectomy with exploration of common duct). But an unlisted-procedure code isn't the best solution in this case.
Solution: If a surgery requires significant additional time or effort that falls outside the range of services described by a particular CPT code, you should append modifier 22 (Unusual procedural services). When properly appended and documented, this modifier will help you gain additional reimbursement.
Tip: Collecting additional reimbursement for unusual services with modifier 22 hinges primarily on the strength of your documentation because the documentation is ultimately what demonstrates the special circumstances, such as extra time or highly complex trauma, that warrant modifier 22 and additional payment.
For every claim with modifier 22, you should submit both a paper claim and the op report. The op report should clearly identify additional diagnoses, pre-existing conditions, or any unexpected findings or complicating factors that contributed to the extra time and effort spent performing the procedure. Also, include a separate cover letter that specifies that this is an -unusual- claim.
Be sure to ask for the money: Payers won't automatically up your payments for modifier 22 claims. You can include your request as a portion of the cover letter that also outlines the procedure's unusual nature.