Influence of Prognostic Factors on the Outcome of Extracorporeal Shock Wave Lithotripsy in Upper Urinary Tract Stone Disease

Background and Aims:

Urolithiasis has an overall prevalence of 2-3% worldwide. Extracorporeal shockwave lithotripsy (ESWL) is one of the noninvasive procedures used for the management of the same. The outcome after ESWL depends on various factors which include position, size, number and composition of stones, double-J (DJ) stenting, presence of hydronephrosis etc. The present study is aimed to assess the effect of stone related factors such as size, number, location; renal factors such as hydronephrosis and patient factors such as obesity, habitus, on the outcome of ESWL in urolithiasis. 

Methods: A set of 280 patients with calculi in the kidney and ureter were subjected to ESWL during theperiod from April 2005 to September 2008, with pre and post-ESWL serial studies of the calculi, including x-ray and ultrasonography (USG). The results were subsequently assessed for the influence of prognostic factors on the outcome, using the Chi-Square test.

Results:

Overall stone free rate was 63%. Upper pole renal stones had a significant clearance over the lower pole stones (p=0.01). Clearance of ureteric stones of <1cm in size, was significantly greater than that of those >1cm (p=0.03). Patients with hydronephrosis showed a statistically significant clearance over patients without hydronephrosis (p=0.034). Clearance of single stone was also significantly better than that of multiple stones (p=0.001). Sixteen patients underwent DJ stenting pre-ESWL, of which 8 were cleared of the stone, without significant difference.

Conclusions:

The size, position, and number of calculi had a significant impact on the outcome after ESWL. Calculi with hydronephrosis obtained better clearance.