MANAGEMENT OF STAGHORN CALCULI
DEFINITION OF COMPLEX RENAL
STONES
Complicated
nephrolithiasis consists of a variety of
stone-bearing situations depending on: 1)-the stone burden and
distribution; 2)- the anatomy of the collecting system; 3)- the stone composition;
4)- the renal function; 5)- associated urinary tract infection.
The
majority of complex renal stones are staghorn calculi, but also multiple stones
behind infundibular stenosis or in a
caliceal diverticulum may be
complicated. Moreover, stones in renal abnormalities, such as
horseshoe-kidney, medullary sponge kidneys,
are most frequently difficult to manage (9). Finally, reduced renal function and/or infection of the renal collecting system always represents a
challenge for the treating urologist.
However, in the following we want to focus on the management of staghorn
stones.
STAGHORN CALCULI
Definition
Principally, staghorn
calculi are defined as branched stones in
the renal collecting system. However, as mentioned before, there are
several different constellations, within this entity. This has been taken into
consideration by the more complex definition of Rocco et al. (10) or the
PICA-classification of Griffith et al. (11). For the modern management of
such stones three factors are of major importance to decide the optimal
treatment: 1)- the overall stone burden; 2)-
the localization of the stone burden (i.e. which and how many calyces
are involved); 3)- the anatomy of the collectingguishing between borderline stones, partial and complete staghorn calculi (12). Of course, the stone
burden can be calculated more exactly
using the area on the
kidney-ureter-bladder (KUB) x-ray plan film, as proposed by Lam et al. (13). This was extremely useful in the
evaluation of different therapeutic approaches, however in the daily routine
the above mention classification proved to be sufficient.
Treatment Options
Whereas
in former times, only the modification of the open renal
surgery, i.e. anatrophic versus radial nephrolithotomy
(4,7), was discussed and even conservative management was optioned
(14), nowadays
a multimodal approach has been developed to minimize morbidity of the treatment
and aiming at optimal long-term results.
This may include: 1)- ex-tracorporeal shock wave lithotripsy with or without
indwelling stent; 2)-percutaneous nephrolithotomy using different devices for
stone disintegration; 3)-the combination of
both techniques as a planned procedure;
4)- retrograde ureteroscopic stone disintegration using a holmium
laser; 5)- open surgery (i.e. anatrophic or radial nephrolithotomy, sinusoidal
pyelolithotomy).
Staghorn stones are
unquestionably an indication for interventional therapy, since all reports following
conservative treatment showed a substantially increased rate of nephrectomy (up to 50%)
and an increase in associated morbidity (i.e. dialysis); in many cases (up to 28%) the disease resulted in
death (5,14). Of course, the choice among the listed treatment modalities mainly depends on the specific
finding of the staghorn stone (i.e. stone classification) (15). On the other hand, further factors such the
age of the patient or the function of
the stone-bearing kidney may be
important (Table-3). Finally, it has to be emphasized that these criteria do not allow exact discrimination
in every case.
Criteria of Success
The goal of any of these procedures is to carry the patient stone-free.
However, with the introduction of ESWL
particularly in case of larger calculi or stones in the lower caliceal
group, even more than 40% of persisting fragments have been accepted (16,17), because in the majority of cases (90%)
these asymptomatic fragments proved to be clinically insignificant (CIRF). This means, that these
fragments did not induce early stone
recurrence, which was different to
the presence of residual stones in the era of open surgery, particularly in case of infected calculi. This may
be attributed to the improved generations of
antibiotics, but also to the fact, that the fragmented calculi are better treatable resulting in some
residual sterile fragments after ESWL (16,17). Nevertheless, any patient
with a treated staghorn stone requires a short a consequent follow-up (18).
|
Criteria
|
ESWL-
|
PCNL-
|
Combination
|
|
|
Monotherapy
|
Monotherapy
|
(ESWL & PCNL)
|
|
Stone burden
|
minor
|
major
|
major
|
|
Distribution of
stone load
|
peripheral
|
central
|
central + peripheral
|
|
Renal collecting
system
|
narrow
|
dilated
|
narrow
/ dilated
|
|
Radiopacity
|
sufficient
|
(in-)sufficient
|
sufficient
|
|
Chemical
composition
|
No cystine
|
-
|
-
|
Indications
for ESWL-Monotherapy
Extracorporeal shock wave
lithotripsy should be performed in case of minor stone burden, peripheral
stone load (i.e. multiple stone-filled calyces) and a narrow renal collecting
system. Moreover, patients with enhanced risk (i.e. cardiosclerosis, respirators problems)
or other difficulties related to percutaneous
surgery (i.e. children, urinary diversion) have to undergo ESWL alone
Indicatios for PCNL-Monotherapy
The percutaneous nephrolithotomy in single session can be
successfully applied for cases of major stone
burden with central (= pelvic) stone load in an enlarged (= dilated) collecting system (i.e. borderline, and
partial staghorn calculi) (Figure-1B). Furthermore, slightly opaque or shock
wave resistant calculi (i.e. cystine) are candidates for PCNL alone (Figure-3).
Indications for the Combination
The
combination of ESWL and PCNL, principally started by the percutaneous approach, is
applied for all cases of major stone burden (i.e. partial and complete staghorn stones) with cen- tral
and peripheral stone load. The rationale for the combination therapy is to reduce the morbidity of the PCNL,
which is carried out in the majority of cases via
one lower pole tract, and the use of ESWL selectively for disintegration of those calculi (parts of the staghorn
stone) that cannot be reached with the nephroscope (Figure-4).
Indications for Open Surgery
Surgery
is a potential treatment option for any staghorn for several reasons. The stone
can be removed by a single procedure with comparable stone-free rates. Therefore,
some authors still advocate open surgical
removal in case of complete stag-horn stones (19-22). However, there is
the problem of loss of renal function after such extensive surgical
interventions like anatrophic intersegmental pyelolithotomy,
which has been reported in the range of 30-50% (23). Overall, the
residual stone rate after open renal surgery is about 15%, with a 30% stone recurrence rate over 6 years and a 40% risk
of urinary tract infections
We
have therefore restricted the indications for open surgery to those cases with
giant stone burden
that cannot be reached endoscopically nor by a considerable number of ESWL-treatments or if additional reconstructive surgery (i.e.
calicoureterostomy, pyeloplasty) is required, Figure-1D (25). Nephrec-tomy
of non-functioning kidneys can be performed laparoscopically (26-27).
Therapeutic Approach
Independently
to the following procedure, every patient
with a staghorn stone requires antibiotic prophylaxis (i.e. gyrase inhibitors) at least 2 days prior to the intervention. In our series 38% of the
patients presented with urinary tract
infections prior to the treatment
(25), 51% of whom were Proteus mirabilis
ESWL-Monotherapy
The techniques of extracorporeal shock wave lithotripsy
have been described in detail previously (28-31). In case of a
larger stone (> 2 cm) we recommend the insertion of a double
J-stent prior the procedure. This avoids obstruction of the ureter
by formation of a steinstrasse, but does not inhibit the passage of fragments
along the stent (13). Staghorn stones should be first treated at the
pelvic part to enable passage of fragments, thereafter the upper
and middle calyces are fo-cussed leaving the lower pole
untreated to avoid that fragments fall into the lower calyces from where further
passage may be prolonged (Figure-3). Depending on the energy
setting of the machine, the number per session should not exceed
4000 impulses. The interval between each treatment should be at
least 2 days.
PCNL-Monotherapy
This is performed as a one-stage
procedure with the patient under general
anesthesia using a retrograde balloon occlusion catheter placed at the
uretero-pelvic junction (12,25). Access is usually through the lower pole posterior calyx with removal of the lower caliceal and pelvic stone burden. In
case of major stone burden, we always place an Amplatz sheath down the
percutaneous tract. This allows removal of
larger stone fragments and reduces the risk of pelviocaliceal influx.
Only in selective cases (i.e. stones less suitable for ESWL, i.e. cystine), we
recommend the puncture of an additional
calyx to achieve complete stone clearance in a single PCNL-session (Figure-3). Another option to access stone burden
in upper and middle calyces may be
the use of a flexible cystoscope together
with a holmium or dye laser introduced via the Amplatz sheath.
Combination
In the combined
approach, we principally recommend to start with a debulking PCNL via the lower
pole posterior calyx. The puncture of the kidney is performed under combined
sonographic and fluoroscopic control. On occasion, multiple tracts (maximum 3) can be made, in case of massive stone
burden (i.e. in the upper dilated calyx).
Open Surgery
Whereas in our earlier
experience the technique of clamping and
cooling was used (32,33), we have
recently preferred the technique of radial neph-rotomies with intraoperative color-duplex-sonography (7). Other options include extended
pyelolithotomy, anatrophic
nephrolithotomy or posterior lower neph-rolithotomy. Nowadays, we would
not put the same emphasis to achieve complete stone clearance, because minor residual stones can be treated
effectively with ESWL.
Comparison with Open Surgery
Our series of open
surgery was performed prior to the
introduction of ESWL and Endourology,The stone distribution in terms of
borderline vs. staghorn stones was similar in both groups, but
the percentage of complete
staghorn stones was higher in the open surgery group (Table-6).
The blood transfusion
rate (37% vs. 10%) was significantly higher after
open surgery, whereas the rate of fever and other minor side effects did not differ in both groups.
Also major complications were
observed in a similar rate (7 vs. 8%) as well as hospital stay (17.2 vs.
15.4).
In the follow-up of both
groups, there are further significant differences (Table-7): the stone-free
rate at discharge after open surgery is signifi-
cantly
higher than after ESWL and endourology (80 vs. 31%). In contrast to this, the
stone-free rate after 42 respectively 36 months does not differ significantly (72 vs. 60%) but is in
favor of the open approach (Figure-6). It is to be noted, on the other hand,
that the majority of the remants after the modern techniques represent CIRF,
whereas the recurrence rate after surgery is significantly higher (20% vs. 7%).
Additionally, the reduction of urinary
tract infection rate is better after
the modern approach (0.51 vs. 0.32 = UTI after/UTI before), Table-7.
DISCUSSION
The
surgical management of urinary stone disease has undergone dramatic changes and
seen the implementation of technological
innovations that are unsurpassed in the field of urological surgery over
the past 20 years. Before these advancements, open surgery was the only
surgical option for neph-rolithiasis. In the current era, the first question in
the management of any stone usually is whether the situation is amenable to
ESWL. This should come
Guidelines for the Treatment of Staghorn Calculi
In this situation, particularly in case of complex
stones, urologists have to define the indications for selection of the
best procedure for treat the individual stone. The Nephrolithiasis Clinical
Guidelines Panel of the American Urological Association reviewed 110 articles
concerned with staghorn calculi resulting to the following guidelines (18).
The committee believed that a newly
diagnosed staghorn was an indication for active treatment. Percutaneous
stone removal, followed by ESWL or repeat PCNL,
should be used for most patients with struvite staghorns. Neither
ESWL-monotherapy nor open surgery should be used as first-line treatment for
staghorns in most patients.
As
options PCNL and ESWL are equally effective in treating small-volume staghorns
when the renal anatomy is normal or near normal. Also as an option, open
surgery is appropriate therapy when the staghorn cannot be managed by any reasonable
number of PCNL and ESWL sessions, i.e. in case of a giant staghorn. Nephrectomy
is a reasonable option for a poorly functioning stone-bearing kidney.
This
summary is in accordance with our previously stated indications
(Table-3). It reflects, however, the limitations of further clarifications mainly due
to the lack of prospective randomized studies as well as an accepted way to
describe staghorns in the literature. We therefore believe that it is important
to focus further on the comparison of the different treatment strategies for
staghorn stone in the
literature. For this
purpose, the changing treatment philosophy and consecutively the criteria of
therapeutic success have to be addressed.
Morbidity of the Treatment
The morbidity of open
surgery have been reported extensively in the literature (4,6,21,22,35-40) including fever (26-29%), blood transfusions
(14-70%), pneumothorax (5%),
recurrent bleeding (4%), septicemia (1%), urinoma/fistula (1%), embolism
(2%), flank abscess (2%), flank pain (16%), flank bulge (5%), incisional hernia (2%) and wound infections (4%) with a
postoperative hospital stay ranging from 11 to 16 days.
Using the modern
approach (3,12,13,15, 25,37-45), the
morbidity mainly is associated to percutaneous
surgery with the need of blood transfusions (5-53%), fever (12-64%),
septicemia (2-4%), pneu-mothorax (2%), A-V malformation requiring superselective embolization (1%), flank abscess
(1%), and colon perforation (1%). The
hospital stay ranged between 9.5 and 18 days.
Our own experience with both methods (Tables-6 and 7) correlates with these data.
There is no doubt, that due to the complexity of the disease both
approaches are associated with significant side effects. On the other hand, there is sufficient evidence that the
overall peri- and postoperative morbidity of ESWL
and endourology is significantly less compared to the open approach. The fact that the modern techniques require
multiple treatment sessions (2.8 vs. 1 session) (18) does not represent
a disadvantage, be- cause it has an impact neither on morbidity nor on the
hospital stay.
The
differences between both approaches are even more pronounced with
respect to the long-term complications.
Whereas the time to normal activity ranged
between 44 to 54 days after open surgery, this was only 21 to 30 days after ESWL plus endourology (38-40). Complete loss of renal function was seen
in 2-8% after open surgery associated with a nephrec-tomy rate of 7-14%. Based on these, earlier
calculations considered an overall dialysis rate of 5% of all patients
with urolithiasis (46,47). The nephrectomy rate
in our series was only 2% using the modern approach, and in a follow-up
period of 3 years there was no further need
of renal ablation due to delayed loss of renal function (Tables-6 and
7). In our personal experience with almost
20 years of multimodal minimally invasive stone management there have been only casuistic cases of stone-related
dialysis in the eighties, however, not a single remembered case in the last ten
years. This underlines the possibilities of ESWL and endourology to
treat and also retreat patients with
complicated stone disease without a significant risk of loss of renal
function.
Residual Fragments
When open surgery was
the standard treatment for the management of renal calculi, the presence of residual fragments suggested a failed
procedure, even those remaining fragments were small. Because residual calculi may act as a nidus for
recurrent stone formation, complete stone removal was the principal goal of therapy. The introduction of
extra-corporeal shock wave
lithotripsy, however, shed a new perspective
on this century-old concept, minimizing the importance of postprocedural residual fragments.
Nevertheless,
in the last decade the main goal of PCNL and ESWL treatment
was to achieve a complete stone-free status ignoring the fact that more and more patients benefit
from successful stone disintegration but with minor asymptomatic residual fragments, the so called “clinically insignificant
residual fragments” = CIRF (Table-5). Of course, the acceptance of this
change of therapeutic endpoints would have a major impact on treatments
strategies for all complex stones. Some
authors do not accept the CIRF-theory
in case of complex stones because the majority of calculi are associated with
infection of the urinary tract and consist of struvite with a high risk of persisting
infection and stone recurrence (19). This is true for open surgery: the stone
free rates at discharge are significantly higher (80-93%) than after the
modern techniques (19-37%). However, after 3 months these figures are rising up
to 67-78%. Our long-term experience after three years revealed an overall stone-free rate of 60%, which was not
statistically significant from the 72% stone-free rate after open surgery.
Subsequently, the recurrence rate was significantly
higher after open surgery (20% vs. 7%) (Table-7).
Infection
Moreover,
about 3 quarters (46 of 61) of the residual fragments were asymptomatic (= CIRF) in
our series, which has been found recently by other authors, too (42). In both
series, more than 50% of stones consisted of
struvite, however, the rate of urinary
tract infection could be significantly reduced (i.e. from 35% to 11%).
The ratio UTI after/UTI before was
significantly higher after open surgery than when using ESWL and endourology (0.51 vs. 0.32)
(Table-7). There may be several
reasons to explain these finding: 1)- residual fragments are better
reachable for antibiotic drugs than
residual stones which still may contain bacteria; 2)- the quality of
antibiotics (i.e. gyrase inhibitors) has improved; 3)- the operative trauma to the collecting system as well as to the
renal parenchyma is significantly less after PCNL plus ESWL than after
open surgery.
Anatomical criteria of the lower caliceal system (i.e. length of the
caliceal neck, pelvic-caliceal angle) may help to predict the chance of
complete stone clearance (48,49).
Nevertheless, one has to accept the fact, that even in case of complex
stone the majority of residual fragments after extracorporeal shock wave lithotripsy are or may become
clinically insignificant (= CIRF) and
only about 10-15% require further treatment (= SIRF). This has been in
accordance to a recent review of the
literature concerning more than 14,000 patients (50).
In
contrast to this, persisting infection still remains
one of the main problems after open surgery
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