Difficult Renal Stones
Stones to Clear
incidence of Steinstrasse secondary to SWL is low for stones less
than 1cm. However, the incidence increases to 75% for large calculi.
Obstruction requiring intervention occurs in 6 and 12% of cases.
Although preoperative ureteral stenting is controversial, stenting
may be wisely indicated in patients with solitary kidneys, unusual
renal anatomy or to aid in stone visualization.
addition to stone size, stone-free rates are determined by stone
location. Upper and middle calyceal calculi have a 70-90% stone-free
rate, whereas, lower pole stones range between 20-70% following
restrictions may impede the passage of stone fragments in up to
70% patients treated by ESWL.
PNL is a better alternative to achieve stone-free rates in patients
with ureteropelvic junction obstruction, infundibular stenosis,
calyceal diverticula, ureteral obstruction, malformed kidneys (horseshoe,
fused and pelvic), obstructive or large adjacent renal cysts. PNL
is ideal for extraction of stones from calyceal diverticula. Alternatively,
retrograde flexible ureteroscopy and laparoscopic techniques have
been described for management of calyceal diverticular calculi.
TD, Preminger GM. Management of calyceal calculi. Urol Clin North
Am 1997, 24:1:81-96.
RG. Rupture of a large calyceal diverticulum. Urol 1997, 49:2:265-266.
RN, Kavoussi LR, Moore RG. Milk of calcium within a calyceal diverticulum.
Urol 1997, 49:4:620-621.
JS, Clayman RV. Percutaneous nephrostolithotomy: What is its role
in 1997? Urol Clin North Am 1997, 24:1:43-58.
GS, Smith AD: Approaches to the superior calyx: Renal displacement
technique and review of options. J Urol 1989, 142:774-777.