Abstract: Mainz pouch II is a reliable and viable technique of continent urinary diversion. Patients are at increased risk of long-term complications including urolithiasis of the upper urinary tract and reservoir. We report the case of a 67-year-old male with prior Mainz pouch II due to invasive bladder cancer treated for a large renal calculus. Percutaneous nephrolithotomy (PCNL) was successfully performed. Stone management in these type of patients is of increased interest due to existed &quot;anatomical challenges&quot; concerning the access and safety during the procedure. To our knowledge this is the first case of PCNL in a patient with Mainz pouch II that has been reported in the literature

Dimitrios Hatzichristou

Dimitrios Paikos

Evangelos Poulios

Ioannis Mykoniatis

MD Stavros Sfoungaristos

Stavros Sfoungaristos

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198) Prague Medical Report / Vol. 117 (2016) No. 4, p. 198–203
Sfoungaristos S.; Mykoniatis I.; Poulios E.; Paikos D.; Hatzichristou D.
Percutaneous Nephrolithotomy  
in a Patient with Mainz Pouch II Urinary 
Diversion: A Case Report
Stavros Sfoungaristos1, Ioannis Mykoniatis1, Evangelos Poulios1,  
Dimitrios Paikos2, Dimitrios Hatzichristou1
11st Department of Urology, Aristotle University, Thessaloniki, Greece;
2Deparment of Gastroenterology, G. Gennimatas Hospital, Thessaloniki, Greece
Rece ived June 18 , 2016 ; Accepted November  14 , 2016 .
Key words: Mainz pouch – Percutaneous nephrolithotomy – Urolithiasis – 
Lithotripsy
Abstract: Mainz pouch II is a reliable and viable technique of continent urinary 
diversion. Patients are at increased risk of long-term complications including 
urolithiasis of the upper urinary tract and reservoir. We report the case of a 
67-year-old male with prior Mainz pouch II due to invasive bladder cancer treated 
for a large renal calculus. Percutaneous nephrolithotomy (PCNL) was successfully 
performed. Stone management in these type of patients is of increased interest 
due to existed “anatomical challenges” concerning the access and safety during the 
procedure. To our knowledge this is the first case of PCNL in a patient with Mainz 
pouch II that has been reported in the literature.
Mailing Address: Stavros Sfoungaristos, MD., PhD., 1st Department of Urology, 
Aristotle University, Thessaloniki, Greece; Phone: +302 310 963 396; e-mail: 
sfoungaristosst@gmail.com
https://doi. rg/10.14712/23362936.2016.20 
© Charles University – Karolinum Press, 2016
199)Prague Medical Report / Vol. 117 (2016) No. 4, p. 198–203
Percutaneous Nephrolithotomy in Mainz Pouch II
Introduction
Mainz pouch II or sigma-rectum pouch represents a continent urinary diversion 
for patients undergoing a radical cystectomy (Fisch et al., 1993). Sigmoid colon is 
utilized to create a low pressure and high capacity reservoir. Patients with urinary 
diversions are at increased risk for upper tract stones formation as well as calculi 
within the diversion segment (Okhunov et al., 2011). There are several treatment 
options for managing renal calculi. Following the establishment of minimal invasion 
techniques, percutaneous nephrolithotomy (PCNL) is considered the preferred 
option for treating renal stones in patients with urinary diversion.
Although PCNL is an efficient and safe technique, it may be a demanding 
procedure in case of urinary diversion. Gaining percutaneous access is a challenging 
step since identification of the neo-ureteral orifice and retrograde opacification 
of the collecting system is commonly difficult. There are several reports in the 
literature presenting the outcomes of PCNL in a variety of diversion types (El-
Nahas et al., 2006; Hertzig et al., 2013). However, data regarding the outcomes of 
PCNL in patients with Mainz pouch II is missing. In the present report, we describe 
the management of a large renal stone in a patient with Mainz pouch II urinary 
diversion by PCNL.
Case report
A 67-year-old Caucasian male was referred to our Department of Urology for 
definitive treatment of a large renal calculus. According to his past medical history, 
he underwent radical cystectomy and Mainz pouch II urinary diversion due to 
invasive bladder cancer 8 years ago. He also underwent an open ureterolithotomy 
for stone removal 2 years ago. The patient was admitted to another institution 
due to acute pyelonephritis 2 months ago. Obstruction of the left kidney was 
identified by ultrasound and a nephrostomy tube was inserted. A computed 
Figure 1 – Computed tomography 
scan revealing the stone  
(arrow – renal stone; arrowhead – 
nephrostomy tube).
200) Prague Medical Report / Vol. 117 (2016) No. 4, p. 198–203
Sfoungaristos S.; Mykoniatis I.; Poulios E.; Paikos D.; Hatzichristou D.
tomography showed a 21×13×15 mm stone within the left renal pelvis (Figure 1). 
Surgical options were discussed and PCNL was considered the optimal option. 
Preoperative urine culture revealed multi-drug resistant Pseudomonas aeruginosa 
and Meropenem was initiated 24 h prior the procedure.
After inducing general anesthesia, the patient was placed in prone position. 
Nephrostomy tube was utilized and antegrade pyelography was performed for 
Figure 2 – Figure 2a (upper left) – an 18G needle inserted in lower calyx; Figure 2b (upper right) – obtaining  
the tract with 30F balloon dilation; Figure 2c (lower left) – inspection of the ureter with flexible nephroscope; 
Figure 2d (lower right) – insertion of Council catheter and antegrade pyelography.
Figure 3 – Neo-ureteral orifice and safety wire.
201)Prague Medical Report / Vol. 117 (2016) No. 4, p. 198–203
Percutaneous Nephrolithotomy in Mainz Pouch II
Figure 4 – Postoperative KUB (kidney-ureter-bladder).
Figure 5 – Postoperative nephrostomography.
the identification of optimal calyx. Puncture of posterior lower calyx was chosen 
using the “bull’s eye” technique. After confirming the site of the needle within the 
collecting system (Figure 2a), a 0.035-inch hydrophilic-coated angled-tip guidewire 
was inserted. A 5F “hockey stick” catheter was then advanced guiding the wire 
down the ureter into the Mainz pouch. At this point, the guidewire was grasped 
and pulled out through the rectum by flexible colonoscope (Figure 3), obtaining 
a “through and through” wire. Guidewire was replaced with Amplatz 0.038-inch 
extra-stiff wire. A gas tube was placed into the pouch through the rectum. The 
202) Prague Medical Report / Vol. 117 (2016) No. 4, p. 198–203
Sfoungaristos S.; Mykoniatis I.; Poulios E.; Paikos D.; Hatzichristou D.
percutaneous tract was established by 30F balloon dilation (Figure 2b). The calculus 
was identified by rigid nephroscope, and fragmentation performed by ultrasonic 
lithotripter. Significant fragments were retrieved by duckbill stone grasper. Following 
stone removal, inspection of the upper calyces and ureter was performed by 
flexible nephroscope (Figure 2c). Spotted remaining fragments were removed by 
tipless nitinol basket while a significant fragment, identified within proximal ureter, 
was fragmented by Ho:YAG laser. Intra-operative stone-free status was confirmed 
by fluoroscopy and antegrade pyelography. An 18F council catheter was placed 
into the renal pelvis (Figure 2d). Sequential exchange and withdrawal of wires and 
catheters were performed antegradely to avoid retrograde microbial migration 
from the pouch to the collecting system.
Postoperative course was uneventful. Gas tube was removed the 1st post-
operative day. Patient was discharged the 2nd post-operative day after removal of 
council catheter. Nephrostomy tube remained closed but not removed. Stone-free 
status was confirmed by KUB (kidney-ureter-bladder) the 2nd post-operative day 
(Figure 4). One month after the procedure, a nephrostomography was performed 
to confirm stone-free status and ureteral patency (Figure 5). Nephrostomy tube 
was safely removed. Stone analysis revealed a mixed type stone, composed by 
struvite and apatite.
Discussion
Mainz pouch II technique was first described in 1993 (Fisch et al., 1993). The recto-
sigmoid reservoir is a low pressure pouch providing continence, protection of 
the upper urinary tract and minimal morbidity (Bastian et al., 2004). Compared 
to other types of continent diversions, Mainz II results to notable decrease in 
mean and peak bowel contraction pressures, as confirmed in postoperative recto-
dynamic studies (Okhunov et al., 2011).
It is well-established that patients undergoing urinary diversion are at amplified 
risk of calculi formation. Reported prevalence varies between 3% and 43%. Risk 
factors include postoperative anatomical changes resulting to urinary stasis and 
mucus reflux into the upper tract, bacterial colonization and diversion-associated 
metabolic disorders (Okhunov et al., 2011).
As it has been previously reported, PCNL represents the preferred treatment 
option for large renal stones in patients with urinary diversion (Okhunov et al., 
2011). Identification of the neo-ureteral orifices and retrograde pyelography are 
challenging steps in these cases. Ultrasound-guided or blind puncture is usually 
needed in order to obtain primary access and opacify the collecting system. In our 
case, ultrasound-guided nephrostomy insertion had preceded the operation. The 
nephrostomy tube was utilized for antegrade pyelography and lower calyx puncture 
under fluoroscopy guidance.
Under the contribution and assistance of gastroenterologists, we obtain a 
“through and through” wire. This step represents a significant part of the 
203)Prague Medical Report / Vol. 117 (2016) No. 4, p. 198–203
Percutaneous Nephrolithotomy in Mainz Pouch II
procedure since it offers maximal safety by providing a retrograde pathway.
Stone analysis revealed a mixed type stone, consisting by struvite and calcium 
phosphate. As it has been reported before, the above stone types represent the 
most common types of diversion stones (Okhunov et al., 2011).
Surgical management of renal stone disease in patients with urinary diversion 
requires detailed evaluation and individualized consideration depending on stone 
location and burden, diversion type and surgeon’s experience. To the best of our 
knowledge, this is the first case of percutaneous nephrolithotomy in a patient with 
Mainz pouch II urinary diversion that has been reported in the English literature. 
Although the experience regarding renal stone management in patients with Mainz 
pouch II is minimal, we may report that PCNL can be performed with safety and 
maximal efficacy. The combination of rigid and flexible scopes is mostly needed to 
obtain postoperative stone-free status. A “through and through” wire is strongly 
advised since it may provide retrograde and antegrade access to the collecting 
system.
References
Bastian, P. J., Albers, P., Haferkamp, A., Schumacher, S., Müller, S. C. (2004) Modified ureterosigmoidostomy 
(Mainz pouch II) in different age groups and with different techniques of ureteric implantation. BJU Int. 
94, 345–349.
El-Nahas, A. R., Eraky, I., el-Assmy, A. M., Shoma, A. M., el-Kenawy, M. R., Abdel-Latif, M., Mosbah, A., Abol-Enein, 
H., Shaaban, A. A., Mohsen, T., el-Kappany, H. A. (2006) Percutaneous treatment of large upper tract 
stones after urinary diversion. Urology 68, 500–504.
Fisch, M., Wammack, R., Müller, S. C., Hohenfellner, R. (1993) The Mainz pouch II (sigma rectum pouch). J. Urol. 
149, 258–263.
Hertzig, L. L., Iwaszko, M. R., Rangel, L. J., Patterson, D. E., Gettman, M. T., Krambeck, A. E. (2013) Urolithiasis 
after ileal conduit urinary diversion: a comparison of minimally invasive therapies. J. Urol. 189, 2152–
2157.
Okhunov, Z., Duty, B., Smith, A. D., Okeke, Z. (2011) Management of urolithiasis in patients after urinary 
diversions. BJU Int. 108, 330–336.


Percutaneous Nephrolithotomy in a Patient with Mainz Pouch II Urinary Diversion: A Case Report

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Percutaneous Nephrolithotomy in a Patient with Mainz Pouch II Urinary Diversion: A Case Report

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