Simpler, Safer Puncture Technique for Percutaneous Nephrolithotomy

By Will Boggs MD

May 04, 2020

NEW YORK (Reuters Health) - A new puncture technique provides a simpler, safer approach for percutaneous nephrolithotomy (PCNL) with reduced fluoroscopy exposure, researchers report.

There are multiple puncture techniques for PCNL. Their main limitation is a low precision in calculating the exact caliceal depth and the exact place to puncture the skin.

Dr. Braulio O. Manzo Perez of Hospital Regional de Alta Especialidad del Bajio, in Leon, Mexico, and colleagues modified the 0-90 degree biplanar technique in an effort to develop a safe and precise percutaneous puncture for PCNL.

First, they selected the calyx to be punctured with the pulsed fluoroscopy C-arm at 0 degrees and placed a visual landmark over the patient's skin (point A). The trajectory from this point they called line A.

They then identified the depth of the calyx with the C-arm rotated under the surgical table (i.e., at 90 degrees) and established line B as the exact calyx level in the patient's anteroposterior axis.

The intersection between lines A and B identified the accurate puncture site at the patient's skin. The needle inserted at this site, moved in the direction of point A, would be monitored with pulsed fluoroscopy until it reached the papilla.

These modifications are useful for both prone and supine positions, the authors say.

This technique proved successful in all 136 patients subjected to standard PCNL for renal stones by the same surgeon between 2015 and 2018, with a mean fluoroscopy time of 69.4 seconds.

After one procedure, the overall stone-free rate was 62.5%, and after an ancillary procedure for residual stones it reached 83.8%, the team reports in Urology.

The overall stone-free rate after one procedure was 85.2% for non-complex stones and 46.7% for complex stones.

Thirty-five patients (25.7%) experienced complications, none of them grade 4 or 5.

"Our first case series with the 0-90 degree simplified fluoroscopic puncture technique shows a similar stone-free rate and safety profile but a low fluoroscopic screening time compared to the most common previously reported fluoroscopic puncture techniques non-focused on low radiation protocols," the authors conclude. "Further studies are required to evaluate the reproducibility, external validation, and the learning curve of our simplified 0-90 degree technique."

Dr. Thomas Knoll of Sindelfingen-Boeblingen Medical Center at the University of Tuebingen, in Sindelfingen, Germany, who co-authored the European Association of Urology 2016 guidelines on diagnosis and conservative management of urolithiasis, told Reuters Health by email, "I am convinced that the best and safest approach to the kidney is by combined ultrasound-fluoroscopy guidance. Simplified pure fluoroscopy guidance seems the wrong concept to me."

Dr. Manzo did not respond to a request for comments.

SOURCE: Urology, online March 14, 2020.