الفهرس 
FOCUS ON PELVICALYCEAL SYSTEM ANATOMYOnly 14 pages are availabe for public view
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Abstract
T
he aim of this work is to determine whether the distance from skin to stone, as measured by computed tomography (CT) scans, could affect the stone – free rate achieved via extracorporeal shock wave lithotripsy (ESWL) in renal stone patients.
The work is a prospective study which include twenty five patients complaining from renal stones measuring between 5 to 20 mm, presented to the urology department in Ain shams university Hospitals
To all the patients history were taken, BMI were measured, Full laboratory evaluation and radiological examination were done
All the patient were scanned with a multidetector row helical CT scanner (HiSpeed Dual, GE medical systems, Milwaukee, USA), and the images were obtained using high quality mode at 200 mA, 120 KV and 5mm collimation reconstructed at 3mm. to measure Stone density in Hounsfield Unit (HU), stone site and stone size, SSD.
All the patients were treated by extracorporeal shock wave lithotripsy (ESWL) using a siemnes modularis lithotripter. where the stone were fragmented under fluoroscopic guidance by a single operator, during each session a constant number of shocks (3000 Shocks) were delivered to a maximal power of 22-24 KV at 120 shocks/min.
Then all the patients were evaluated after one to six weeks from the last ESWL session with a plain KUB film and non-enhanced spiral computed tomography to assess stone fragmentation. And the patients were classified according to ESWL result into two groups, Successful group (stone free or clinically insignificant stone fragments) and Failure group (With residual fragments more than 3mm in size).
In our study, we found that, age, sex, laterality and location of stones does not have any significance in predicting the outcome of ESWL on upper urinary tract stones.
While SSD as measured by non contrast spiral computed tomography (NCSCT) is a good predictor of stone disintegration by ESWL. where it showed that SSD >11.5cm is a predictor of ESWL failure while stones with SSD <11.5cm had high rates of stone disintegration by ESWL.
While stone density as measured by non contrast spiral computed tomography (NCSCT) in Hounsfield Unit (HU) was a predictor of stone disintegration by ESWL. where it showed that a mean stone density >1050 HU is a predictor of ESWL failure while stones with stone density <520 HU had high rates of stone disintegration by ESWL.
Also stone size as measured by NCSCT was a predictor of ESWL failure, where stones above 1.5 cm had high incidence of failure while stones below 0.8 had high incidence of success.
So for any stone measuring between 5-20 mm in the upper urinary tract it is very beneficial to do NCSCT pre treatment with ESWL, so that if the SSD is below 11.5cm and size below 7 mm, a high rate of success will be expected. While for stones with SSD above 11.5cm and size above 15 mm, a high rates of failure of stone disintegration by ESWL will be expected. So another way of treatment should be done for such patients to avoid unnecessary exposure of renal parenchyma to shock waves and complications, invariably alternative treatments are then needed, incurring additional medical expenses.