Routine Flexible Nephroscopy for Percutaneous Nephrolithotomy for Renal Stones with Low Density: A Prospective, Randomized Study

Abstract

We evaluated the usefulness of routine flexible nephroscopy during percutaneous nephrolithotomy. Patients diagnosed with kidney stones who were scheduled to undergo percutaneous nephrolithotomy between March 2011 and July 2012 were randomized into 2 groups. Group 1 underwent standard percutaneous nephrolithotomy using rigid nephroscopy. Group 2 underwent flexible nephroscopy, in addition to standard percutaneous nephrolithotomy and laser lithotripsy or basket catheter stone extraction, as needed. Surgery was performed subcostally and with minimal percutaneous access in group 2 to use the advantages of flexible nephroscopy. We compared the 2 groups in terms of preoperative stone characteristics and postoperative success criteria, including the stone-free rate, bleeding, number of access sites, etc. The study included 61 males (76.3%) and 19 females (23.8%) with a mean ± SD age of 43.75 ± 12.4 years (range 19 to 74). There was no significant difference in stone size, HU density or stone location between the 2 groups. Comparison of perioperative and postoperative parameters revealed a higher stone-free rate (92.5% vs 70%), fewer access sites and a lower hematocrit decrease in group 2. The stone-free rate was higher in patients with stones with a density of less than 677.5 HU (100% in group 2 vs 64.7% in group 1). Routine flexible nephroscopy during percutaneous nephrolithotomy was associated with a higher stone-free rate, fewer interventions and less bleeding, especially in patients with low HU density stones.