Staghorn Calculi: Analysis of Treatment Results between Initial Percutaneous Nephrostolithotomy and Extracorporeal Shock Wave Lithotripsy Monotherapy with Reference to Surface Area

Abstract

Treatment recommendations and results reported for the management of staghorn calculi are highly variable. In an attempt to provide a more objective means to compare treatment results for staghorn renal calculi, stone burden as measured by stone surface area was used. Stone surface area was determined by computer analysis. A total of 380 cases of staghorn calculi treated at the same institution was evaluated. Treatment consisted of initial percutaneous nephrostolithotomy with or without extracorporeal shock wave lithotripsy (ESWL*) in 298 cases and ESWL monotherapy in 82. When considered as a group, the overall stone-free rate for initial percutaneous nephrostolithotomy (mean surface area 1,378.3 mm.2) was 84.2% compared to 51.2% (p less than 0.0001) for ESWL monotherapy (mean surface area 693.4 mm.2). For staghorn calculi smaller than 500 mm.2 a stone-free rate of 94.4% was achieved in the percutaneous nephrostolithotomy with or without ESWL group compared to 63.2% for ESWL monotherapy (p = 0.0214). For calculi of 501 to 1,000 mm.2 the stone-free rates were 86% and 45.7%, respectively (p less than 0.0001). When stone surface area exceeded 1,000 mm.2 the stone-free rate for percutaneous nephrostolithotomy with or without ESWL was 82.4% but it was only 22.2% for ESWL monotherapy (p = 0.0002). Overall, when adjusted for stone surface area the odds of being stone-free were more than 8 times higher for initial percutaneous nephrostolithotomy versus ESWL monotherapy (odds ratio = 8.36, p less than 0.0001). While percutaneous nephrostolithotomy with or without ESWL appears to be the procedure of choice for most staghorn stones, ESWL monotherapy may have a role for some stones smaller than 500 mm.2. In 12 such cases associated with a nondilated renal collecting system (mean surface area 380.5 mm.2) a stone-free rate of 91.7% was achieved. The number of procedures required to complete therapy was higher in the initial percutaneous nephrostolithotomy group (2.8 versus 2.1, p less than 0.0001). Although complications were more common in the ESWL monotherapy group (manifested as obstruction in 30.5%), bleeding requiring blood transfusion was more frequent in the initial percutaneous nephrostolithotomy group (9.4%).

Contemporary Practice of Percutaneous Nephrolithotomy: Review of Practice in a Single Region of the UK

“…Most studies from large, single centres with an established expertise in the management of renal tract calculi quote stone clearance rates of 79-95%. [3][4][5][6] To our knowledge, the present data reflect 'real-life' activity and are likely to be a truer representation of urinary stone surgery in a diverse, non-specialised geographical region.…”

Influence of stone burden and stone configuration on outcomes of percutaneous nephrolithotomy

“…Also, the technique for determining stone surface area should be accurate, reproducible, easy to perform, readily available and affordable. 6,7 Techniques for determining stone surface area include the use of a graph paper, planimeter, CT, computer image analysis. Routine use of CT is a cumbersome and expensive, but results are accurate, rapid.…”

“…Reproducibility was also within 5%. 6,7 In the modern management of renal stones, three factors are important in selecting the optimal treatment, the total stone burden, the location of stone burden, and the anatomy of collecting systems. To this purpose, effect of stone burden and stone configuration on stone-free rate, mean operative time, complication rate, and the requirement of the secondary procedures following percutaneous nephrolithotomy procedure were studied.…”

“…2 Lam et al have elegantly shown that stone surface area measurements with computers are feasible, economical, highly accurate and reproducible. 6,7 Though threedimensional CT is ideal for measuring stone surface area, it is an expensive and additional cost for the patient. Hence, it was not used in present study.…”

“…The important difference in the data is that study by Lam et al included only staghorn calculi, where as we report results on all renal calculi, of which 46.7% were staghorn stones. 6,7 The classification of staghorn stones as partial or complete is subjective and variable. The use of stone surface area eliminates differences among urologists regarding the definition of what constitutes a staghorn stone.…”