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


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).


CONCLUSIONS
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.
Department of Urology, Ankara University School of Medicine, Ankara, Turkey.
Mehmet Ilker
MI
Gokce
Department of Urology, Ankara University School of Medicine, Ankara, Turkey.
Eriz
E
Ozden
Department of Urology, Ankara University School of Medicine, Ankara, Turkey.
Evren
E
Suer
Department of Urology, Ankara University School of Medicine, Ankara, Turkey.
Basak
B
Gulpinar
Department of Urology, Ankara University School of Medicine, Ankara, Turkey.
Omer
O
Gulpınar
Department of Urology, Ufuk University School of Medicine, Ankara,Turkey.
Semih
S
Tangal
D000328:Adult; D005260:Female; D006801:Humans; D007669:Kidney Calculi / Q000000981:diagnostic imaging* / Q000601:surgery; D008297:Male; D008875:Middle Aged; D009403:Nephrostomy, Percutaneous / Q000379:methods*; D011184:Postoperative Period; D011446:Prospective Studies; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D036542:Tomography, Spiral Computed / Q000379:methods*; D016896:Treatment Outcome; D014463:Ultrasonography