California Subscriber
Answer: The answer depends on the size of the kidney stone. If the stone is smaller than 2 cm and you performed the procedure described by code 50080 (Percutaneous nephrostolithotomy or pyelostolithotomy, with or without dilation, endoscopy, lithotripsy, stenting, or basket extraction; up to 2 cm), Medicare will not reimburse your surgical assistant claim.
If the kidney stone is larger than 2 cm, you can append modifier -80 (Assistant surgeon) to your claim. The fee schedule assigns a "2" assisted surgery code to 50081 (Percutaneous nephrostolithotomy or pyelostolithotomy, with or without dilation, endoscopy, lithotripsy, stenting, or basket extraction; over 2 cm), which means that "Payment restriction for assistants at surgery does not apply to this procedure. Assistant at surgery may be paid."
Modifier -80 applies to surgeries during which your surgeon acts as the primary surgeon's "extra set of hands." But if the urologist were to encounter an unex-pected problem during the surgery and require your sur-geon's temporary assistance, you would report modifier -81 (Minimum assistant surgeon) instead.
According to the September 1992 CPT Assistant , you should choose modifier -81 if "during the operation a minor problem is encountered that requires the service of an assistant surgeon for a relatively short period of time."