Comparison of imaging modalities for detection of residual fragments and prediction of stone related events following percutaneous nephrolitotomy

Abstract

Introduction Achieving stone free status (SFS) is the goal of stone surgery. In this study it is aimed to compare effectiveness of unenhanced helical computerized tomography (UHCT), KUB and ultrasonography (US) for detection of residual RFs and predicition of stone releated events following percutaneous nephrolitotomy (PNL).Materials and Methods Patients underwent PNL for radiopaque stones between November 2007 and February 2010 were followed. Patients were examined within 24-48 hours after the procedure by KUB, US and UHCT. For stone size 4 mm was accepted as cut off level of significance.Sensitivity and specificity of KUB and US for detection of RFs and value of them for prediction of stone related events were calculated.Results SFS was achieved in 95 patients (54.9%) and when cut off value of 4 mm for RFs was employed, SFS was achieved in 131 patients (75.7%). Sensitivity was 70.5% for KUB, and 52.5% for US. UHCT was shown to be significantly more efficient for detection of RFs compared to both KUB (p=0.01) and US (p=0.001). When cut off level of 4 mm employed, sensitivity of KUB and US increased to 85.7% and 57.1%. Statistical significant superiority of UHCT still remained (p value vs. KUB: 0.03 and p value vs. US: 0.008).Conclusion UHCT is the most sensitive diagnostic tool for detecting RFs after PNL. It has higher sensitivity regardless of stone size compared to KUB and US. Additionally UHCT has higher capability of predicting occurrence of stone related events.

Stone residual fragments: A thorny problem

“…[17][18][19][20] Despite known limitations, US is the best method for assessing hydronephrosis, 21 redefining an important role for this diagnostic tool during standard follow-up and limiting the use of ionizing radiation. Currently, the CT scan, with a sensitivity of over 90%, is the best imaging technique for detecting renal and ureteral stones 22 due to its high resolution and easy detection of small sized stones (1-2 mm). Moreover, the use of the CT scan to assess RFs has had the important effect of reducing the SFR, which is almost always evaluated with KUB and US.…”

Perkutan Nefrolitotomi Tedavi Başarısını ve Komplikasyonlarını Öngörmek için Kullanılan Croes Taş Skorlama Sisteminin Validasyonu

“…Literatürde PNL sonrası taşsızlık oranları %72 ile %84 arasında değişmekte, staghorn dışı taşlarda bu oran %100' e ulaşmaktadır. (18)(19)(20)(21)(22)(23). Smith ve ark.…”

Evaluation of postoperative hydronephrosis following semirigid ureteroscopy: Incidence and predictors

“…[15,16] Also the value of non-contrast CT to detect residual fragments following surgery has been shown to be higher than ultrasonography and abdominal X-ray. [17] Therefore this methodology takes away the drawbacks related to non-homogeneity of the imaging modalities.…”