Pelvicalyceal stone load: a factor affecting the outcome of extracorporeal shockwave lithotripsy for renal pelvic calculi

Noncontrast computed tomography factors that predict the renal stone outcome after shock wave lithotripsy

OBJECTIVES

Extracorporeal shock wave lithotripsy (ESWL) is a popular treatment for nephrolithiasis. We took advantage of noncontrast abdominal computed tomography (NCCT) to search the possible prognostic factors including abdominal fat distribution influencing stone-free rate.

METHODS

From August 2008 to August 2010, 145 patients who had renal calculus and had undergone ESWL were retrospectively reviewed. All of them received NCCT assessment before ESWL and were followed up after 1 month for stone clearance. These patients were divided into two groups: one was the stone-free group and the other was the residual-stone group. Affecting parameters included stone size, location, stone surface area, Hounsfield unit density (HU density), skin-to-stone distance (SSD), and abdominal fat area as analyzed between these two groups.

RESULTS

Of 145 patients, 70 were stone-free and 75 had residual stone after ESWL treatment and 1-month follow-up. From univariate analysis, stone size, HU density, SSD, and stone surface area were significant predicting factors for ESWL success. On multivariate analysis, the important factors influencing ESWL outcomes were HU density and stone surface area (odds ratio 1.002 vs. 77.18, respectively; P<.05). Abdominal fat accumulation and distribution had no significant difference between these two groups.

CONCLUSION

This study revealed that stone size, HU density, SSD, and stone surface area were associated with stone-free rate after ESWL treatment. Therefore, these factors could be used to assess the feasibility of ESWL before deciding the treatment strategy. Abdominal fat distribution had no significant impact on ESWL outcome for renal stones.

Role of Helical Nonenhanced Computed Tomography in the Evaluation of Acute Flank Pain

OBJECTIVE

To evaluate the role of helical nonenhanced computed tomography (NECT) in the diagnosis of acute flank pain.

METHODS

Seventy-five consecutive patients were analysed retrospectively for profile, loin pain, urine analysis and NECT findings. Diagnostic accuracy of NECT for urolithiaisis was calculated. The value of combined microhaematuria and NECT in the diagnosis of flank pain was also highlighted. The potential for identifying phleboliths and alternative diagnoses on NECT was also explored.

RESULTS

There were 46 males and 29 females with an average age of 42.2 years. Forty-four patients presented with acute left flank pain. NECT carries a sensitivity and specificity of 96% for the diagnosis of stone disease. Combined with microhaematuria, NECT has 100% accuracy in picking up urinary tract stones.

CONCLUSION

NECT is the first imaging investigation of choice for the evaluation of patients presenting to the emergency department with flank pain and suspected renal colic.

Stones in anomalous kidneys: results of treatment by shock wave lithotripsy in 150 patients

OBJECTIVE

To determine the efficacy of shock wave lithotripsy (SWL) in anomalous kidneys.

METHODS

From October 1990 to October 2002, 150 patients (93 men and 57 women) with anomalous urinary tracts, including 45 horseshoe kidneys, 57 duplex kidneys, 30 malrotated kidneys, 14 pelvic and four crossed ectopic kidneys were treated with SWL for urolithiasis at the Gazi University Faculty of Medicine. Shock wave lithotripsy was performed with Siemens Lithostar plus (Siemans, Erlanger, Germany) device and all procedures were carried under fluoroscopic control.

RESULTS

The mean shock wave number and intensity received by the patients was 3770 (range, 1380-4100) shocks and 18.4 (range, 16.1-19) kV per session, respectively. The minimum success rate was obtained in patients with lower calyceal (50%) followed by middle calyceal (60%) calculi. The stone-free rate decreased and the number of sessions per patient increased with increasing stone diameter (dm). In patients with a stone dm > 30 mm, only 34% could be stone-free, compared to a rate of 92% for calculi dm < 10 mm. The overall stone free rate at the third month was 68%. The best stone-free rates were obtained in patients with ureteral duplication (80.7%). The stone-free rates in horseshoe, malrotated, pelvic and crossed ectopic kidneys were found to be 66.7%, 56.7%, 57.2% and 25%, respectively.

CONCLUSION

Shock wave lithotripsy might be an effective and minimally invasive treatment alternative in stone-bearing anomalous kidneys. The type of anomaly, stone burden and localization seem to be the main parameters effecting the treatment success.