Ham. Mosli et al., A STUDY OF URINARY STONES REQUIRING LARGE DOSE EXTRACORPOREAL SHOCKWAVE (ESWL) TREATMENT, Saudi medical journal, 17(6), 1996, pp. 726-731
Objectives: To identify factors that may play a role ih the increased
resistance of renal stones to extracorporeal shockwave lithotripsy (ES
WL) treatment. Methods: A retrospective study on 290 ESWL patients who
received more than 10,000 shocks. The following factors were studied:
Age, sex, stone size, site, multiplicity, difficulty of x-ray stone v
isualization during localization for ESWL treatment; previous surgery
for stone disease; degree of hydronephrosis; stone clearance at 6 mont
hs after 20,000 shocks; staff versus resident ESWL machine operator an
d finally the type of stone. Results: One hundred and fifty-five (53%)
patients had solitary renal stones, Ninety-four (32%) patients had mu
ltiple renal, forty (14%) had ureteric and one (0.3%) patient had blad
der stone. Of the 155 solitary stones, which is the largest group requ
iring high dose ESWL therapy, only 46 (30%) were of surface area equal
to or greater than 500 mm(2) indicating that other factors are also i
mportant besides the size in this regard, The majority of the stones a
nalyzed were of very hard consistency: 60% calcium oxalate, 8% contain
ed urate and 5% composed of cystine: Early analysis of post-ESWL passe
d stone fragments and reviewing the medical records of those patients
with previous history of stone disease to identify stone type from pre
viously passed renal stones or stones obtained surgically, helps early
recognition of stone composition and possibly predicts treatment outc
ome. Conclusions: We observed that some patients with certain renal an
d ureteric stones, even of moderate or small sizes, require a higher E
SWL dose than others. Increased stone hardness may explain slow stone
clearance in this group of patients. Understanding this possibility he
lps to make a realistic anticipation of the period of morbidity and tr
eatment cost.