Urology Coding Alert

Question: I'm trying to find the code for a percutaneous cystolithotomy. I can only find the code for an open cystolithotomy. Per the op note, "The patient has a neobladder, and a physician placed two percutaneous tubes via interventional radiological techniques. The urologist used a NephroMax balloon dilator to enlarge the tract of one of the percutaneous access sites without difficulty. The tract was easily dilated and the sheath was then advanced over the balloon. Access was then easily maintained in the neobladder. A combination of ultrasonic lithotripter and the lithoclast was used to break up the stones. Stones were removed with a combination of suction through the ultrasonic probe and a stone grasping forceps." What codes should I be using? Georgia Subscriber Answer: If the urologist performed the neobladder access, choose code 53899 (Unlisted procedure, urinary system) for the percutaneous access to the neobladder. There is no CPT code [...]