Rod Test in Percutaneous Nephrolithotomy: A Practical Guide to Selective Nephrostomy Placement

Percutaneous nephrolithotomy (PCNL) is the gold standard for treating renal calculi. With the advancement in technology, the recent trend has been toward tubeless procedures, but some cases still need placement of a nephrostomy.

The objective of our study was to assess the intraoperative role of the "metal dilator rod" in deciding whether to place a nephrostomy.

A prospective study was conducted from 15 November 2024 to 15 May 2025, and 83 consecutive patients undergoing PCNL were included in the study. All procedures were performed by a single endourologist. After completion of PCNL, a metal dilator rod was inserted through the Amplatz sheath under fluoroscopic guidance into the pelvis, followed by removal of the Amplatz sheath. The percutaneous nephrostomy (PCN) tract was observed for three to five minutes for any active bleed. Nephrostomy was inserted only in patients with brisk bleeding.

The average age of the patients was 38 ± 17 years in tubeless and 42 ± 11 years in tube PCNL. The male-to-female distribution was 57:26. Out of 83 patients, 72 patients underwent tubeless PCNL based on the rod test. In 11 patients, nephrostomy was placed immediately because of active bright bleeding from the PCN site and clamped. Nephrostomy was removed after 48 hours once it was clear. The average drop in hemoglobin was 1 ± 0.5 g/dl. However, in the patients (n = 11) in whom the PCN was placed, the average drop in hemoglobin was 2.5 g/dl. However, all patients remained hemodynamically stable and did not need transfusion.

The rod test is a good adjunct for deciding whether to place a nephrostomy at the end of the procedure.