all kidney stones will spontaneously pass from the
kidney out into the urine. Most stones under
.5cm will spontaneously pass from the kidney.
Most stones greater than 1cm will not pass. If
the stone must be removed two commonly employed
methods are percutaneous nephrolithotrypsy (PCNL)
and extracorporeal shock wave lithotripsy (ESWL).
The type of procedure depends on the type of stone
and its size. Typically, small stones can be
treated with ESWL, while larger stones require PCNL.
ESWL is typically not successful for cystine stones.
Some large struvite stones require a combination of
PCNL and ESWL.
shock wave lithotripsy):
procedure uses sound waves to break apart the stone.
Originally, people were placed in large water baths
which is good at transmitting sound waves.
Newer generation machines transmit the shock wave
through a water cushion or tube which is placed over
the patient. The stone must be found by either
or flouroscopy, which is like an xray machine but
uses television monitors rather than xray film for
constant monitoring. Often as part of ESWL,
the urologist will perform cystoscopy
and place a stent (a small tube) that passes from
outside the patient, through the urethra, up the
ureter, and into the kidney. This tube will
remain in place for a few days. It allows for
easier passage of the tiny stone fragments that are
created after exploding the stone with shock waves.
ESWL can also be
used successfully for stones that are stuck in the
procedure is more commonly used when ESWL cannot
(e.g. cystine stones, large staghorns, unsuccessfuly
ESWL, calcified aorta, and other causes).
First a tube is inserted into the patient's back
into the kidney to create a tract. A scope is
run through the tract to directly visualize the
stone inside the kidney. Ultrasound equipment
can then be inserted to break up the stone.
While watching the stone through the scope, the
stone fragments can be grasped with special
equipment and pulled through the tract out from the
the advent of PCNL and ESWL, open surgical
procedures were performed. This is less often
necessary now, but sometimes is still performed
especially for large complicated staghorn stones.