STONE DENSITY HOUNSFIELD UNIT VALUE DETERMINED BY UNENHANCED COMPUTED TOMOGRAPHY IN PREDICTING THE OUTCOME OF PERCUTANEOUS NEPHROLITHOTOMY

Abstract

BackgroundA successful percutaneous nephrolithotomy (PNL) requires appropriate preoperative planning, and non-contrast computerized tomography NCCT has become an important imaging method in diagnosing urolithiasis, providing stone measurements, location, and density (Hounsfield units). Stone density (HU) measurement is routinely performed in clinical practice to define the hardness and composition of kidney stones and predict the stone treatment outcome. ObjectiveTo evaluate the outcome of percutaneous nephrolithotomy regarding stone-free rate, complications, and operation time using the Hounsfield unit value determined by non-contrast computed tomography. Patients and MethodsSixty patients were electively selected for PCNL; the inclusion criteria were all adult patients with renal stones who needed PNL. The exclusion criteria were renal stones in the obstructed pyelonephritic kidney, stone with sepsis, ectopic kidney, and transplanted kidney. The patients were divided into two groups—the low HU group (HU ≤ 1000) and the high HU group (HU> 1000) based on stone density. In addition, the intraoperative and postoperative data, including the operation time, stone-free rate, and post-PCNL complications, were recorded—a comparative study designed between the two differences in HU stone density and the outcome of the procedure. ResultsOur study includes 31 (51.7%) males and 29 (48.3%) females. Twenty-seven patients had an HU value ≤ 1000, and 33 had an HU value >1000. Intraoperative complications occurred in 3 (4.92%) patients with high stone density, including extravasation (n = 2) and bleeding (n = 1). Postoperative complications occurred in 11 (18.03%) patients (nine patients with low and two with high stone density). The postoperative stone residual was found in 4 patients with low stone density. Operation time was longer in high-stone-density groups than in low-stone-density groups (P-value < 0.001). ConclusionPreoperative assessment of stone density impacts outcomes in percutaneous nephrolithotomy. High stone densities are associated with longer operating times, higher intraoperative complications, and higher stone-free rates. Conversely, Low-density stone has a shorter operative time, higher postoperative complications, and lower stone-free rates.