1. PERCUTANEOUS Nephrolithotripsy (PCNL) Percutaneous nephrostomy was a
procedure known since 1955 (Goodwin et al). However, it was not until 1976 when the
first percutaneous nephrostomy for the specific purpose of removing a kidney stone was
performed by Fernstrom and Johannson. Over the next few years, Smith and colleagues
at the University of Minnesota, Alken and Marberger in West Germany, and Wickham
and colleagues in the United Kingdom, began to remove selected stones in the renal
pelvis and ureter through percutaneous nephrostomy tracts. By the early 1980s, it was
apparent that it was possible to remove renal stones safely and reliably percutaneously,
not only through a previously made PCN tract, but also as a single stage procedure with
considerably shortened period of hospitalization (Segura et al., 1983). TECHNIQUE OF
PERCUTANEOUS STONE REMOVAL The procedure may be divided into two parts:
(A) access into the collecting system and (B) removal of the stone. I. Access The
excretory urogram or retrograde pyelogram should be reviewed to determine the
relationship of the stone to the collecting system and to determine the optimum access
tract. The retroperitoneal location of the kidney permits access through a posterolateral
"window". Access should be performed under fluoroscopic or ultrasonic control.
Optimum access is generally through a lateral calyx, one of the lower polar calyces in
most instances. If the goal is a caliceal stone or a diverticular stone, access should be
through that particular calyx or diverticulum. Approach through the upper polar calyces
is useful for access to the pelvis and UPJ, but the risk of pleural injury is significantly
increased.The procedure is mostly done under epidural, spinal or general anesthesia, but
can be done under intravenous sedation and local anesthesia as well. An 18-gauge needle
is placed through the flank into the kidney at the point where access is desired. A guide
wire of .035 or .038 size is passed through the needle. It is very desirable that this wire be
placed down the ureter as far as the pelvic ureter in order to minimize the possibility of
inadvertent loss of the tract.The tract is enlarged by passing serial or telescopic Teflon or
metal dilators co-axially over the guide wire. Dilatation proceeds under fluoroscopic
control to 30 Fr and an Amplatz sheath is passed over the last dilator, to provide direct
access to the collecting system. The nephroscope is passed through the sheath to visualize
the inside of the collecting system. II. Stone Removal Small stones can be removed
intact with forceps or basket. More commonly, some form of power lithotripsy is
required to break the stone into manageable fragments. The options available now are,
ultrasonic lithotripsy, electrohydraulic lithotripsy, and pneumatic lithotripsy. Whatever
the choice of energy source, the action of the probe is that of a "jackhammer," battering
the stone into progressively smaller pieces (Fig. 1). The pieces are removed as they are
broken up. Stone removal continues until the patient is free of stone or until it is
necessary to stop the procedure. Common reasons for this include progressive bleeding
which obscures the surgeon's vision so that the rate of stone removal is considerably
slowed, and extravasation of irrigating fluid. If the patient is not free of stone at the
termination of the procedure, the nephroscope can safely be reinserted through the same
tract after 48 hours. At this point, the tract is matured and bleeding has almost always
stopped, so that removal of residual fragments is usually straightforward. As the size of
the stones and complexity of these situations increase, the odds rise considerably that a
second and occasionally a third treatment will be required. At the end of the procedure, a
nephrostomy tube is placed through the tract into the collecting system, large enough to
maintain an adequate tract to permit blood and clots to drain readily. After 48 hours, a

2. nephrostogram is obtained. If there are no leaks, the nephrostomy tube is clamped. If the
patient tolerates this procedure, the tube is removed and the patient is discharged from the
hospital. The drainage site will usually close within 24 hours. Time of disability varies;
most patients return to average activity levels within a week or so. A return to vigorous
activity should probably take place in another week. PCNL : Indications Table 1 :
AUA Nephrolithiasis Clinical Guidelines Panel Report on management of staghorn renal
calculi (1994) Treatment recommendations for calculi in non-dilated non-obstructed adult
collecting systems Stone size Surface area Treatment Exceptions >1 cm <100> 3 cm
>1000 mm2 PCNL - Since the availability of extracorporeal shock wave
lithotripsy, it has become the treatment of choice for small and medium sized
uncomplicated stones. Following over a decade’s experience with ESWL, which has
allowed better understanding of its usefulness and limitations, the indications of PCNL
have been redefined. 1. Obstructive Uropathy If an anatomic abnormality is present that
will prevent stone fragments from passing spontaneously, shock wave lithotripsy is
usually contraindicated. These situations are ideal for PCNL, inasmuch as the obstructive
uropathy can also be corrected after stone removal employing endourological procedures.
Ureteropelvic junction (UPJ) obstruction may coexist with calculi in the collecting
system. Such stones are best removed by percutaneous means because the obstruction can
be treated by endopyelotomy, usually at the same time. Caliceal diverticula often contain
stones, and their connections to the collecting system are usually such that broken
fragments after shock wave lithotripsy will not only remain in the diverticula but the
obstructive uropathy will remain untreated. Management of diverticular stones by PCNL
with enlargement of the connection to the collecting system or obliteration of the
diverticulum by electrocoagulation is the usual treatment today. 2. Stone Size Although
it is possible to treat large stones with shock wave lithotripsy, the high re-treatment rates
and the high residual stone rates make such treatment unattractive (Lingeman et al.,
1989). PCNL is particularly effective with such stones because of its ability to remove
large volumes of stone material over a relatively short period of time. For this reason, if
the stone is 2.0 to 3.0 cm or more, PCNL is preferred, especially if other factors may
compromise the utilization of shock wave lithotripsy. (Table 1) Staghorn calculi
constitute a special problem that has always tested surgical abilities. Most staghorn stones
are composed of struvite, although stones composed of uric acid, calcium oxalate
monohydrate, and especially cystine occasionally fill enough of the collecting system to
give it a staghorn appearance, Because most staghorn calculi are composed of struvite,
they are infected, and as such no substitute exists for complete removal. This was true
when all such stones were treated by open surgical removal, and it is true now. Failure to
achieve complete stone removal allows the persistence of infection and the eventual re-
growth of the stone. Although excellent results can be achieved by percutaneous means
alone, with stone-free rates of 85 to 90 per cent in experienced hands (Patterson et al.,
1987), struvite staghorn stones are usually managed by a combination of PCNL and
shock wave lithotripsy. 3. Anatomic Abnormalities Some patients are so large or so
constructed that shock wave lithotripsy is impossible because the stone cannot be placed
in the focal point of the machine. Percutaneous removal will be possible if the distance,
from the skin to the stone is less than the length of the nephroscope or the sheath. 4.
Stone location Stones located in the lower pole calyces are less likely to pass after shock
wave breakup, particularly if the collecting system is grossly dilated or otherwise abnor-

3. mal. If it is important that all fragments be removed, PCNL is probably preferable. 5.
Stone Composition Struvite stones should be treated with PCNL in order to be sure that
all the fragments are removed. Stone composition is otherwise an important consideration
due to the fact that with ESWL hard stones will frequently not fragment into pieces small
enough for spontaneous passage with minimal discomfort. This same hard stone may be
equally difficult to remove with power lithotripsy after percutaneous access, but it will be
possible to remove the pieces via PCNL, irrespective of how difficult it was to break up
the stone. The commonest hard renal stones are composed of calcium oxalate
monohydrate. As these stones become larger, the more likely it is that multiple shock
wave lithotripsy treatments or other instrumentation may be necessary. One should
consider that it might be more cost-effective and actually less morbid to remove these
stones with PCNL. 6. Certainty of the Final Result Residual stones are not acceptable
for many patients. The most common example is the commercial airline pilot. However,
many people find themselves considerably inconvenienced, for whatever reason, by the
uncertainty as to whether a small fragment might pass. The very high stone-free rate after
PCNL makes this method an ideal choice for such people. 7. Other Modality Failure As
mentioned, shock wave lithotripsy may fail or ureteroscopy may fail. Equally, stones may
remain after an open surgical procedure. PCNL may retrieve these otherwise lost
procedures. Contra-indications of PCNL The only absolute contraindications for PCNL
are uncorrected bleeding disorder and pregnancy (due to the risk of radiation). The other
relative contra indications which may be considered are, medical problems making the
patient unsuitable for anesthesia, and, stone location making access risky, (eg, pelvic
kidney), By and large, the procedure is possible in majority of the patients, including
those considered unsuitable for the other modalities like open surgery and shock wave
lithotripsy. RESULTS The advent of shock wave lithotripsy has changed the definition
of what constitutes a successful result. Considerable discussion has occurred about
"clinically insignificant residual fragments" ("CIRF"), referring to broken up fragments
of various sizes and their propensity for spontaneous passage. Because of a lack of
unanimity as to the precise definition of CIRF, a consensus has emerged that the only true
definition of success is a stone-free state. This point is an important consideration in
measuring the effectiveness of PCNL against other methods of stone management. If
results are restricted to the best selected patients, i.e., those with the least difficult stones
to access, stone-free rates of 98 to 99 per cent can be achieved (Brannen et al., 1985;
Lingeman et al., 1989; Segura et al., 1985; White and Smith, 1984). As the size of the
stone increases, and as the complexity of the situation increases, the stone free rate drops
to 75 to 80 per cent. Better results are achievable with greater effort, and it becomes a
matter of judgment as to whether a given residual stone is worth the effort required to
remove it. COMPLICATIONS OF PERCUTANEOUS STONE REMOVAL As with
any other surgical procedure, problems may complicate any aspect of the percutaneous
stone removal. One may conveniently divide events into three groups: (A) complications
related to access, (B) complications related to tract dilatation, and (C) complications
related to stone removal. A. Complications Related to Access The ultimate success of
the procedure is a function of adequate access. Poor tract placement may make safe,
expeditious stone removal an impossibility. Prudence dictates that a sub-optimal access
point should be changed prior to dilatation and lithotripsy. The retroperitonal position of
the kidney permits access through a percutaneous window that enables entry into the

4. kidney without trauma to adjacent peritoneal structures. Pathologic states and variation in
normal antomy may result in situations in which damage to adjacent organs can occur.
1. Spleen: Inadvertent perforation or damage to the spleen is unlikely in the average
situation, but if splenomegaly is present to any degree, damage is possible. 2. Pleura:
Most of the time, if access is below the 12th rib and if the kidney is in normal position, it
is unlikely that the pleura will be injured. The risk of injury is a function of the frequency
of upper pole approaches to the collecting system and whether or not the approach was
above the 12th rib. A chest tube should be placed in any doubtful situation. 3. Colon:
The close proximity of the colon to the kidney, the normal anatomical variations, and the
occasional patient with pathologic enlargement of the colon makes this rare event a
possibility. 4. Kidney: Optimum access traverses the bulk of the thickness of renal
parenchyma to enter the collecting system through one of the calyces. Placement of the
tract in a line too medial or too lateral may tear the parenchyma. The pedicle or other
large branch vessels may be injured if the access tract enters the collecting system media]
to the calyces or if the tract goes beyond the collecting system inadvertently. Proper
placement of the tract through the calyx and infundibulum and into the renal pelvis
minimizes the risk of such injury. Despite these efforts, significant bleeding may occur
during access and dilatation of the tract. This blood is most often venous and usually
stops with tamponade from the dilators and from the nephrostomy tube itself. Arterial
injury is probably a product of access too near a susceptible vessel coupled with the
effects of dilatation and efforts to remove stone. Variations in the anatomy of the kidney
together with limitations inherent in access methods ensure that arterial injury will always
be a real, if rare, complication. 5. Sepsis: Many patients experience a rise in temperature
after stone removal, although true sepsis is rare, Preoperative urine culture results will
identify the patient who should be treated prior to the procedure. Special attention should
be paid to those patients with infected stones. It is usual to provide a prophylactic
antibiotic cover, using a broad-spectrum antibiotic that covers the common uro-pathogens
for these patients. B. Complications Related to Tract Dilatation The shorter the tract,
the less difficult it is to dilate. As the tract lengthens, the guide wire is more likely to
buckle, increasing the risk of being unable to complete dilatation. In obese patients, the
kidney nay be mobile enough that the dilators simply push the kidney away. The dilators
should usually be placed no further than the stone itself. The reason for this is that more
aggressive dilatation could generate a perforation of the collecting system Where the
stone fills the entire pelvis there may not be enough room for the stone and the dilator.
Rarely, some event may suggest that the procedure should be stopped at this point. After
48 to 72 hours of nephrostomy tube drainage, bleeding will have stopped and the tract
will be well epithelialized, permitting uncomplicated stone removal. C. Complications
Related to Stone Removal Problem at the time of stone removal may be summarized as
those related to bleeding, extravasation, inadvertent perforation of the collecting system
and incomplete stone removal. 1. Bleeding: Although a certain amount of bleeding
occurs all throughout the procedure, significant blood loss may complicate the situation
at any time. The most common type of bleeding is venous, which may be compared with
the sinus bleeding that occurs with transurethral resection of the prostate. This can be
managed by clamping the nephrostomy tube for 30 to 45 minutes. This step allows a clot
to form in the collecting system, tamponading the bleeding. Arterial bleeding is a more
serious problem. This may occur as an acute event at the time of lithotripsy (primary) but

5. also may occur in the postoperative period up to a week or 10 days (secondary). The
rapidity of blood loss, its red arterial character, and its lack of response to tamponade
suggest injury to a significant vessel. Arteriography should be performed immediately.
This will confirm the diagnosis, usually revealing a pseudo-aneurysm, but arteriography
will also permit treatment of the problem by embolization of the offending artery.
Surgery should be avoided if possible, as at exploration nephrectomy or partial
nephrectomy may appear the only alternatives because of the emergent character of the
situation. Most large series report an incidence of this problem less than 1 per cent. 2.
Extravasation: Normal saline should be used as the irrigation fluid to minimize adverse
effects when extravasation occurs. When an Amplatz sheath is employed, most of the
irrigation fluid travels out the sheath, rendering extravasation less likely. Despite the
technical details, the operating personnel should monitor the quantity of irrigation fluid
used and compare this amount with the quantity in various collecting bags. Discrepancies
that cannot be accounted for should suggest the possibility of extravasation. Intravascular
extravasation may be suggested by venous bleeding and confirmed by injection of
contrast medium. This finding usually means the procedure must be terminated for the
day, otherwise large quantities of irrigation fluid will be rapidly absorbed.
Retroperitoneal extravasation is inevitable if the collecting system has been perforated. If
the perforation was identified when it was made, it may be possible to complete the
procedure by rigorously controlling the amount of irrigation. Sometimes, retroperitoneal
extravasation may not be obvious unless it is noted that the kidney seems to be moving
“away" from the flank and that the nephroscope must be placed farther in to access the
stone. Intraperitoneal extravasation is rare, and will happen only if there is peritoneal
laceration with a pelvic tear. 3. Retained Fragments: As in any method of stone
management, the presence of residual fragments on a post-procedure plain film can be an
unwanted finding. Reinsertion of the nephroscope through the tract, kept open by the
nephrostomy tube, will permit removal of the stone fragments. One may decide that the
effort necessary to remove these stones is not justified by the clinical situation. If a
fragment large enough to obstruct the ureter should pass in the immediate post-procedure
period, the tract may not close after the nephrostomy tube is removed. Sometimes stones
are extruded through the collecting system or are noted in the perinephric tissues outside
the kidney. It is not necessary to remove these stones, as experience has shown them to
be clinically unimportant. Their main import has been to generate confusion on
subsequent plain abdominal radiographs. 4. UPJ Obstruction: Occasionally follow up
studies show partial or complete UPJ obstruction resulting in progressive dilatation of
pelvi-caliceal system. This may be either due to pre-existing obstruction missed at the
time of operation, or may be the result of trauma to UPJ during surgery. The incidence is
greatest in cases where the stone was impacted at the UPJ. SUMMARY Percutaneous
surgery is an effective and safe method for the management of a wide variety of renal and
ureteral stones. Today, it is selected mainly in certain specific situations in which the
result justifies its invasive nature. Recognition of which patient can benefit from the
procedure minimizes the number of other less successful attempts at stone removal and
optimizes the chance that the problem will be managed safely, expeditiously, and
economically. 1 day ago Delete