What is the correct CPT code for removal of a renal calculus via retrograde endoscopy through an established nephrostomy (nephroscopy through an existing tube in the kidney)?

CPT Coding for Renal Calculus Removal via Nephroscopy

The correct CPT code for removal of a renal calculus via retrograde endoscopy through an established nephrostomy is 50561.

Understanding the Procedure and Code Selection

The scenario describes a patient requiring removal of a calculus from the renal pelvis via nephroscopy through an established nephrostomy tract. This is a specific procedure that requires precise coding:

• 50561 - Renal endoscopy through established nephrostomy or pyelostomy, with or without irrigation, instillation, or ureteropyelography, exclusive of radiologic service; with removal of foreign body or calculus

This is the appropriate code because:

1. The procedure involves endoscopic examination of the kidney (nephroscopy)
2. It's performed through an established nephrostomy tract
3. The primary purpose is removal of a calculus (kidney stone)
4. The stone is located in the renal pelvis

Differentiating from Other CPT Codes

Let's examine why the other codes mentioned are not appropriate:

• 50580 - Renal endoscopy through nephrotomy or pyelotomy, with or without irrigation, instillation, or ureteropyelography, exclusive of radiologic service; with removal of foreign body or calculus

  • This code is for nephroscopy performed through a surgical incision (nephrotomy/pyelotomy), not through an established nephrostomy tract

• 50130 - Pyelotomy; with removal of calculus

  • This is an open surgical procedure, not an endoscopic approach

• 50060 - Nephrolithotomy; removal of calculus

  • This code describes an open surgical procedure for stone removal, not an endoscopic approach through an established tract

Clinical Considerations

When performing nephroscopy through an established nephrostomy tract:

• The tract should be mature (typically 1-2 weeks old) to minimize complications 1
• The procedure allows direct visualization of the collecting system and removal of stone fragments 2
• This approach has advantages over open surgery, including reduced morbidity and shorter recovery time 2
• Technical success rates for percutaneous nephrostomy procedures approach 100% for dilated collecting systems 1

Potential Complications and Management

Complications associated with nephroscopy through established tracts include:

• Bleeding (mild hematuria occurs in approximately 50% of patients) 2
• Infection
• Catheter displacement
• Tract disruption

Proper tract maturation before performing the procedure helps minimize these complications 1.

Conclusion

For the described procedure of removing a renal calculus via nephroscopy through an established nephrostomy tract, the correct CPT code is 50561. This code specifically describes endoscopic removal of a calculus through an established nephrostomy, which accurately represents the procedure performed.