|Year : 2019 | Volume
| Issue : 3 | Page : 119-125
Complications of ureteroscopic stone lithotripsy: A multicentre local study
Murtadha Almusafer1, Ali Mohammed Jawad Al-Tawri2
1 Department of Urology, University of Basrah, College of Medicine, Basrah, Iraq
2 Basrah Health Directorate, Urologist at Basrah Teaching Hospital, Basrah, Iraq
|Date of Submission||11-Aug-2018|
|Date of Acceptance||27-Aug-2018|
|Date of Web Publication||23-Aug-2019|
University of Basrah College of Medicine, Basrah
Source of Support: None, Conflict of Interest: None
Aims: The aim of the study was to evaluate semi-rigid retrograde ureteroscopic pneumatic stone lithotripsy complications and to compare between the stone-related factors associated with the occurrence of these complications. Settings and Design: The Study design was a prospective study. Subjects and Methods: Two hundred and fifty-one patients (143 male and 108 female) who underwent (266) ureteroscopic procedures for their ureteral stones in Basra Teaching Hospital and also in communication with the other local centres at the south of Iraq extending from January 2015 to August 2017. Full medical and surgical history, routine laboratory investigations and imaging study were done preoperatively. After taking informed consent, pre-operative antibiotic was given, procedure done under general or regional anaesthesia using (8 or 9.5) ureteroscopy (URS) and lithotripsy, double j stent inserted when indicated. Stone-free status was reached when all the stones were destructed and extracted while gravels and fragments <2 mm left for spontaneous passage. The patient was discharged home after 24 h unless complications occurred. Statistical Analysis Used: Descriptive statistics were done to measure the frequency of intra- and post-operative complications using SPSS version 21. Results: Stone-free status was achieved in 81.95%. Regarding intra-operative complications, perforation occurred in 10.1%, of them 8.6% were minor and 1.5% were major, mucosal abrasions occurred in 7.1%, false passage in 2.25%, stone retropulsion in 4.1% and intraoperative bleeding in 1.8%. Post-operative complication includes fever (6.4%) and ureteral obstruction (6%). Conclusions: Semi-rigid URS has gained wide acceptance worldwide and seems to be safe and efficient in managing ureteral stones with low rate of intra- and post-operative complications.
Keywords: Complications, lithotripsy, ureteroscopy
|How to cite this article:|
Almusafer M, Jawad Al-Tawri AM. Complications of ureteroscopic stone lithotripsy: A multicentre local study. Hamdan Med J 2019;12:119-25
| Introduction|| |
Ureteroscopy (URS) first performed in 1929 by Young and Mckay using a cystoscope in hugely dilated ureter,, but the rigid ureteroscope was not done until 1977 when Goodman reported the first rigid URS for therapeutic purposes. Since its clinical introduction in 1982 by Perez-Castro and Martinez-Pineiro, URS had been impressively developed due to the technical improvements of new and smaller urological armamentarium. It is widely applied, safe and effective procedure in the routine urological practice, but sometimes it may fail., Although URS is relatively safe procedure, it is still considered the most common cause of ureteral injury., With improvements in URS and intracorporeal lithotripsy, the success rate of ureteroscopic stone lithotripsy has increased from 50% to 97%,, and the overall complication rate has decreased to 12%–15%, with a major complication rate of 0.8%–1.5%.,
Many articles classified complications into intra- and post-operative complications. Intra-operative complications include major and minor ones. The major complications are (ureteral avulsion which is the most devastated complication and intussusception of the ureter). The minor complications include perforation of the ureter which is a most common ureteroscopic complication, false passage,mucosal abrasions, stone retropulsion, instruments' breakage or malfunctioning, extravasation, bleeding, difficult access and incomplete stone destruction.,,,,,,,,,,,
The post-operative complications include early major (infection and steinstrasse) and early minor (obstruction of the ureter and vesicoureteral reflux).,,
Late post-operative complication includes stenosis of the ureter. The mechanism is likely to be multifactorial: a direct trauma such as a perforation, temporary ischemia due to prolonged use of a ureterorenoscope with an excessive-sized calibre, the presence of an impacted stone  and the result of a thermal trauma are the greatest risk factors. The objectives are to evaluate the complication which occurred during ureteroscopic stone destruction and to study the factors associated with the occurrence of these complications.
| Subjects and Methods|| |
A prospective cohort study conducted in Basra Teaching Hospital and other local centres at the south of Iraq extending from January 2015 to August 2017.
Two hundred and seventy-seven patients were enrolled in this study, attended the outpatient clinic or emergency unit in Basra General Hospital including patients who were referred from private clinics and also in communication with the other centres in Iraq. After exclusion of the cases with pathologies other than ureteral calculi, 251 patients (143 male and 108 female) were left as the study population with 266 ureteroscopic procedures (15 patients had bilateral ureteroscopic interventions). A full medical and surgical history was recorded, clinical examination was performed and informed consent was obtained. Investigations include (renal function tests, urinalysis, urine culture, new imaging including ultrasonography of urinary system, kidney, ureter and bladder [KUB], computed tomography scan and/or intravenous urography (IVU) in addition to the routine pre-operative investigations were performed) and the dimensions of the stone(s) were calculated from the imaging preoperatively.
The endourological procedure
The procedure was in lithotomy position under general or regional anaesthesia, after preparation and draping, pre-operative antibiotic (ceftriaxone 1 g IV infusion was given), an 8 or 9.5 Fr semi-rigid ureterposcope with video monitor, light source, stone grasper or dormia, lithoclast and normal saline irrigating fluid were used. The URS was inserted, safety flexible guidewire (0.035/0.038-inch) was passed through the ureteral orifice and the visualised stone was fragmented under direct vision using laser and pneumatic stone lithotripsy according to the stone hardness. In a very tortuous ureter, double guidewire technique was used to reach up the stone. Stone fragments were taken out by grasper to attain complete clearance while stone gravels of approximately 2 mm size were left for spontaneous passage and the stone-free status was determined either by direct visualisation of the involved ureter and by radiographic follow-up imaging. All the procedures done without the use of anti-retropulsive devices to minimise the complications which might result from these accessories. At the end of procedure, a double j (DJ) stent was placed in most of the patients. Before removing DJ stent, a KUB was requested. The patient kept on broad-spectrum antibiotic cover and analgesia on the post-operative period (based on the patient's condition). Patients were discharged within 24 h unless complications or co-morbidity necessitate prolonged hospitalisation.
Stone impaction was defined as the stone causing complete ureteral obstruction on imaging or present at the same site for more than 3 months with documented signs of impaction during the procedure.
Descriptive statistics were done to measure the frequency of intra- and post-operative complications using Statistical Package for the Social Sciences version 21.
| Results|| |
This study included a total of 251 patients (143 male and 108 female) with 266 ureteroscopic procedures. Male/female ratio was (1.45:1), their age ranged from 13 to 78 years with a mean age of 41.4 ± 6.3 years and stone size ranged from 6 to 20 mm with mean stone size 12.4 mm as shown in [Table 1].
The complete stones' destruction achieved in 81.95%, while partial stone destruction occurred in 11.65% and procedure failed in 6.4%. The outcome of ureteroscopic stone lithotripsy is shown in [Figure 1].
Minor perforations occurred in 8.6% of patients with higher percentage in those with larger stone size (77.8%), upper ureteral location (66.6%) comparing with lower location which was only 33.3%, more in obstructed stones (77.8%) than nonobstructed (22.2%) with duration more than 2 weeks in (74%), also found more in patients who had received extracorporeal shock wave lithotripsy (ESWL) before the intervention and their operations done as an emergency (70.4%) than those who underwent an elective URS.
Only four patients suffered from major perforations (1.5%). All of them had impacted stone >10 mm (100%) which located in upper ureter in 66.6%, 75% of them had multiple stones and impacted for <2 weeks and had received ESWL before and they underwent an elective procedure.
False passage occurred in 2.25% of patients, 66.7% of them had >10 mm stone and lower ureteral location for more than 2 weeks and had a history of ESWL, 83.3% impacted and causing complete ureteral obstruction.
Stone retropulsion occurred only in 11 patients (4.1%), 72.7% of them had a large stone (>10 mm size) non-obstructed with a history of ESWL and underwent emergency intervention, and (80.8%) of patients had the upper ureteral location of their stones.
Intraoperative bleeding occurred in 1.8% of the patients, 80% of them had larger size multiple stones with duration of symptoms more than 2 weeks and underwent elective surgery, all of the stones are obstructing (100%). The intraoperative complications are shown in [Figure 2] and [Table 2]. The types of perforation are shown in [Table 3].
Regarding post-operative complication, 16/251 of patients developed post-operative fever which required prolonged post-operative monitoring or readmission, of them 75% had larger stone size (more than 10 mm), 81.25% had multiple stones with duration of symptoms more than 2 weeks, 68.75% had obstructing stone and underwent elective surgery and 56.25% had bilateral ureteral stones as shown in [Table 4] and [Figure 3].
Obstruction of the ureter postoperatively occurs in 16/266 ureteroscopic procedures (68.75%); of them larger size stone more than 10 mm located in the lower ureter, 75% of the patients had multiple stones obstructing the ureter who had ESWL in their history, 81.25% of patients had duration of symptoms more than 2 weeks as shown in [Figure 4].
| Discussion|| |
The ureter is a fragile structure which makes it more prone to get injured during endourologic interventions. The distension which occurs during ureteroscopic procedures compromises its vascular flow, thus exposing the wall to a higher risk of injury. Consequently, the size of ureteroscope plays a major role in the occurrence of perforation. A correlation exists between ureteroscopic size and ureteral injury.
The success rate of semi-rigid URS found in this study is 81.95% which agrees with that obtained by Mandal et al.(81%–94%) and lower than the study of Ibrahim which was 88.5% and higher than the study of Dongol et al. which was 69.33% and Bayar et al. (69%).
The overall intra-operative complication rate in this study was 25.35%. Most of the complications were minor. This finding was in accordance with that of Perez Castro et al. (3.8%–7.7%) and slightly lower than that of Ibrahim which was 26.35%.
In this study, the procedure failed in 6.4% of patients and this was higher than that found by Tepeler et al. (1.8% only).
The high likelihood of perforation occurs in the impacted lithiasis because of chronic inflammation, interstitial fibrosis and ureteral oedema which weaken the ureteral wall.
Major perforations in this study occurred in 1.5% and this is higher than that obtained by Tepeler et al., who reported incidence of only 0.8% and also higher than that mentioned by Georgescu et al. which was only 0.7%. and D'Addessi et al. which was only 1% and lower than obtained by öǧreden et al. which was 4.6%.
All of the patients who experienced major perforations underwent procedures with (8 or 9.5 Fr) ureteroscopes, and this finding goes with that of Tepeler et al., who concluded that perforation and avulsion arose when using a 9.5 Fr ureteroscope, whereas the procedures performed with a 4.5 Fr ureteroscope rarely show ureteral trauma.
This study demonstrates that perforations occurred when using pneumatic lithotripsy in stone fragmentation and this goes with (De La Cruz et al) who reported that the type of the lithotripsy does impact the incidence of perforation which was higher when using pneumatic lithotripsy.
Stone location and impaction affect the likelihood of perforation. For proximal and lumbar ureters being 1.6% and 0.7%, respectively, and 64% of the perforations at lumbar ureter occurred with impacted lithiasis. These findings correlate with our results which showed that most of perforations occurred in impacted proximal ureteral stones.
With regard to the location also, stones at upper ureter are larger and they are difficult to descend. This location and size make them more difficult to approach with increased duration of procedure. These factors expose the patients for additional risk of complications including perforation. Consequently, the treatment of large impacted lithiasis at proximal and lumbar ureters implies a higher risk of ureteral injuries and perforations as also concluded from this study.
We face cases of ureteral perforation (whether major or minor) in this study and this may be explained by the fact that we are dealing with a lot of large and impacted stones for a long duration. All of these act as risk factors for ureteral perforation due to their effect on the ureteral wall (inflammation and oedema which lead to the weakening of the ureteral wall). Furthermore, a large proportion of ureteral perforation occurred in the upper ureter which is physiologically explained by the deficit muscle coats which adversely affects its strength.
The use of smaller size ureteroscope, more flexible guidewire (like hydrophilic ones), laser stone lithotripsy and more expert surgeons may probably decrease the incidence of such problems.
This study demonstrates that obstructing upper ureteric stones, larger stone size (>10 mm) with long duration of symptoms and history of ESWL are risk factors for ureteric perforations which goes with study done by El-Nahas et al., who found that, in addition to surgeon's inexperience, lithiasis size and location and whether the stone was impacted or not are significant factors affecting perforation incidence. Many other studies demonstrate a higher perforation incidence in patients with large size calculi.,,
Öǧreden et al. reported that complications were not seen in situation with a stone size smaller than 5 mm (it was seen with stones larger than 5 mm). Another studies found that the complication rate was the highest in situations where the stones are larger than 10 mm. Perez castro et al. mentioned that higher incidence of perforation occurred in patients with impacted ureteral stone. Another study done by Bayar et al. also showed that proximal location increases the complication risk by about 2 folds.
Stone retropulsion occurred in 4.1% in this study which was slightly higher than that obtained by Tepeler et al., who had stone retropulsion rate of 3.9%. and by öǧreden et al. which was 3.7% and much higher than the results in a study done by Shrestha which was only 1.27% and lower than that found by Georgescu et al. which was 5.6% and lower than the result of Li et al. which was 4.6%. We noticed that the stone retropulsion occurred more in stones located in proximal ureter and this is logic and correlates with the findings of Sen et al. and who reported that most of stone migration to the kidney occurred when dealing with proximal ureteral stones, and also they found that most cases occurred when using pneumatic lithotripsy.
The use of antiretropulsion devices (like stone cone, etc.,) and avoidance of the modalities of lithotripsy with high risk of retropulsion may aid in minimising this complication. Furthermore, the use of flexible ureteroscope in which the stone can be fragmented inside the kidney when it is migrated proximally increases the stone-free status.
Intraoperative bleeding according to this study occurred in 1.8% which is close to the result of a study done by Ogreden et al. (1.9%) but higher than the result of Georgescu et al. which was only 0.1%. and also higher than that of D'Addessi et al. which was 1.4%. We found that bleeding occurred more if we deal with patients who had multiple stones than patients with one stone. This finding is matched with a study done by Öǧreden E et al., who reported that more bleeding was encountered during multiple stones' ureteroscopic lithotripsy. In this study, the bleeding which occurred intraoperatively was mild and self-limited but adversely affected the field vision which mandated the termination of the procedure after putting a DJ stent.
Post-operative fever occurred in 6.4% which was higher than what mentioned in the European Association of Urology guidelines (fever or urosepsis occurred at the rate of 1.1%). Bloom J et al. demonstrated postoperative urosepsis in 4.3% Mandal et al. reported a urosepsis rate of 0.8%. Öǧreden et al. reported the incidence of 10.2% and Shrestha  report a 45% in his study and also reported in the study of Hossain et al. which are higher than what is found in this study. Fever probably occurred when managing large long-standing impacted stones which usually accompanied by infection and required a prolonged surgery and high volume highly pressurised irrigation fluid., In addition, the stone nidus may be bacteria which adds further risk for the development of post-operative fever.,,
- Upgrading and updating the instruments, accessories and surgeon's experience are important in reducing complications and improving success rate
- More detailed studies with larger sample size are recommended
- It is worthy to train and know how to avoid the occurrence of these possible complications. Surgeon's experience (the attendance of workshops, good training of the juniors and residents), the presence of good facilities (including instruments, good accessories, monitors and cameras), the use of careful technique (like the direction of the pneumatic probe or laser fibre which should be parallel to the ureteral lumen, careful disintegration of the stone near the wall of ureter to avoid direct or thermal injury, avoiding forceful introduction and dangerous dilatation of the ureter by ureteroscope), avoiding high irrigation pressure and pre-operative treatment of already present urinary tract infection are very important factors aiding in the prevention of disastrous complications.
| Conclusions|| |
- Semi-rigid URS seems to be safe and efficient in managing ureteral stones with low rate of intra- and post-operative complications, most of them were successfully managed conservatively
- The occurrence of complications encountered during ureteroscopic stone lithotripsy was highly affected by many factors such as stone size, location, number, whether obstructing or not and the duration of symptoms.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Gaizauskas A, Markevicius M, Gaizauskas S, Zelvys A. Possible complications of ureteroscopy in modern endourological era: Two-point or “scabbard” avulsion. Case Rep Urol 2014;2014:308093.
Maxim L, Bănuţă I, Scârneciu I. Ureterorenoscopy: Indications and complications-a retrospective study. Bull Transilvania Univ Brasov 2016;9:18-22.
Reddy SV, Shaik AB. Ureteroscopic lithotripsy; Retrospective review of mid and lower ureteric stones-its results and complications. Urol Nephrol Open Access J 2016;3:71.
Shrestha NM. Semi-rigid pneumatic ureteroscopicremoval of ureteric stone; Seven years' experience at Nepalgunj medical college. J Nepalgunj Med Coll 2017;13:10-2.
Georgescu D, Mulţescu R, Geavlete B, Geavlete P. Intraoperative complications after 8150 semirigid ureteroscopies for ureteral lithiasis: Risk analysis and management. Chirurgia (Bucur) 2014;109:369-74.
Taie K, Jasemi M, Khazaeli D, Fatholahi A. Prevalence and management of complications of ureteroscopy: A seven-year experience with introduction of a new maneuver to prevent ureteral avulsion. Urol J 2012;9:356-60.
Chen DY, Chen WC. Complications due to surgical treatment of ureteral calculi. Urol Sci 2010;21:81-7.
Sofer M, Watterson JD, Wollin TA, Nott L, Razvi H, Denstedt JD, et al.
Holmium: YAG laser lithotripsy for upper urinary tract calculi in 598 patients. J Urol 2002;167:31-4.
Elashry OM, Elgamasy AK, Sabaa MA, Abo-Elenien M, Omar MA, Eltatawy HH, et al.
Ureteroscopic management of lower ureteric calculi: A 15-year single-centre experience. BJU Int 2008;102:1010-7.
Grasso M. Ureteropyeloscopic treatment of ureteral and intrarenal calculi. Urol Clin North Am 2000;27:623-31.
D'Addessi A, Bassi P. Ureterorenoscopy: Avoiding and managing the complications. Urol Int 2011;87:251-9.
Burks FN, Santucci RA. Management of iatrogenic ureteral injury. Ther Adv Urol 2014;6:115-24.
Chen SS. A rare complication of ureteroscopy: Ureteral avulsion. Urol Sci 2014;25:105.
Lee H, Ryan RT, Teichman JM, Kim J, Choi B, Arakeri NV, et al.
Stone retropulsion during holmium: YAG lithotripsy. J Urol 2003;169:881-5.
Monga M, editor. Ureteroscopy: Indications, Instrumentation and Technique. Current Clinical Urozlogy. New York: Springer Science + Business Media; 2013. p. 162-9.
Sen H, Bayrak O, Erturhan S, Urgun G, Kul S, Erbagci A, et al.
Comparing of different methods for prevention stone migration during ureteroscopic lithotripsy. Urol Int 2014;92:334-8.
Dretler SP. The stone cone: A new generation of basketry. J Urol 2001;165:1593-6.
Arthur D, Gopal H, Glenn M, Louis R. editors. Smith's Textbook of Endourology. 3rd
ed. Hoboken, New Jersey, USA: Blackwell Publishing Ltd.; 2012. p. 506-12.
Schuster TG, Hollenbeck BK, Faerber GJ, Wolf JS Jr. Complications of ureteroscopy: Analysis of predictive factors. J Urol 2001;166:538-40.
Geavlete P, Georgescu D, Niţă G, Mirciulescu V, Cauni V. Complications of 2735 retrograde semirigid ureteroscopy procedures: A single-center experience. J Endourol 2006;20:179-85.
Reddy TG, Assimos DG. Optimizing stone-free rates with ureteroscopy. Rev Urol 2015;17:160-4.
Göktaş C, Horuz R, Akça O, Cetinel AC, Albayrak S, Sarıca K, et al.
Fragmentation without extraction in ureteral stones: Outcomes of 238 cases. Urol Res 2012;40:383-7.
Jung H, Osther PJ. Intraluminal pressure profiles during flexible ureterorenoscopy. Springerplus 2015;4:373.
Hafez KS, Wolf JS Jr. Update on minimally invasive management of ureteral strictures. J Endourol 2003;17:453-64.
de la Cruz JE, Morcillo E, Folkersma LR, Álvarez S, Margallo FM, Soria F. Complications of endourologic procedures: A review on iatrogenic ureteral perforation. ARC J Urol 2017;2:17-24.
Traxer O, Thomas A. Prospective evaluation and classification of ureteral wall injuries resulting from insertion of a ureteral access sheath during retrograde intrarenal surgery. J Urol 2013;189:580-4.
Mandal S, Goel A, Singh MK, Kathpalia R, Nagathan DS, Sankhwar SN, et al.
Clavien classification of semirigid ureteroscopy complications: A prospective study. Urology 2012;80:995-1001.
Ibrahim AK. Reporting ureteroscopy complications using the modified clavien classification system. Urol Ann 2015;7:53-7.
] [Full text]
Dongol UM, Acharya L, Subba K, Khambu B, Joshi R, Shrestha SK, et al.
Semirigid ureteroscopy with pneumatic lithotripsy for ureteral stone. J Nepal Health Res Counc 2011;9:21-4.
Bayar G, Tanriverdi O, Horasanli K, Dalkiliç A. Ureteroscopy outcomes, complications and management of perforations in impacted ureter stones. J Urol Surg 2016;3:133.
Perez Castro E, Osther PJ, Jinga V, Razvi H, Stravodimos KG, Parikh K, et al.
Differences in ureteroscopic stone treatment and outcomes for distal, mid-, proximal, or multiple ureteral locations: The clinical research office of the endourological society ureteroscopy global study. Eur Urol 2014;66:102-9.
Tepeler A, Resorlu B, Sahin T, Sarikaya S, Bayindir M, Oguz U, et al.
Categorization of intraoperative ureteroscopy complications using modified Satava classification system. World J Urol 2014;32:131-6.
Öǧreden E, Oǧuz U, Demirelli E, Benli E, Sancak EB, Gülpinar MT, et al.
Categorization of ureteroscopy complications and investigation of associated factors by using the modified clavien classification system. Turk J Med Sci 2016;46:686-94.
Galvin DJ, Pearle MS. The contemporary management of renal and ureteric calculi. BJU Int 2006;98:1283-8.
El-Nahas AR, El-Tabey NA, Eraky I, Shoma AM, El-Hefnawy AS, El-Assmy AM, et al.
Semirigid ureteroscopy for ureteral stones: A multivariate analysis of unfavorable results. J Urol 2009;181:1158-62.
Mursi K, Elsheemy MS, Morsi HA, Ali Ghaleb AK, Abdel-Razzak OM. Semi-rigid ureteroscopy for ureteric and renal pelvic calculi: Predictive factors for complications and success. Arab J Urol 2013;11:136-41.
Kassem A, Elfayoumy H, Elsaied W, Elgammal M, Bedair A. Laser and pneumatic lithotripsy in the endoscopic management of large ureteric stones: A comparative study. Urol Int 2012;88:311-5.
Geraghty R, Abourmarzouk O, Rai B, Biyani CS, Rukin NJ, Somani BK, et al.
Evidence for ureterorenoscopy and laser fragmentation (URSL) for large renal stones in the modern era. Curr Urol Rep 2015;16:54.
Li YC, Pan YS, Chen SL, Chang CY. Ureteroscopic manipulation of ureteral calculi: Experience in a regional hospital. Urol Sci 2012;23:45-7.
Bloom J, Fox C, Fullerton S. Sepsis after elective ureteroscopy. Canadian Journal of Urology 2017;24:9017-23.
Hossain GZ, Hasan MR, Rahman M, Ahmed M. Ureterorenoscopy and pneumatic lithotripsy in the management of ureteral calculus. J Chittagong Med Coll Teach Assoc 2008;19:11-4.
Fan S, Gong B, Hao Z, Zhang L, Zhou J, Zhang Y, et al.
Risk factors of infectious complications following flexible ureteroscope with a holmium laser: A retrospective study. Int J Clin Exp Med 2015;8:11252-9.
Gu SP, Huang YT, You ZY, Zhou X, Lu YJ, He CH, et al.
Clinical effectiveness of the polyScope™ endoscope system combined with holmium laser lithotripsy in the treatment of upper urinary calculi with a diameter of less than 2 cm. Exp Ther Med 2013;6:591-5.
Flannigan R, Choy WH, Chew B, Lange D. Renal struvite stones-Pathogenesis, microbiology, and management strategies. Nat Rev Urol 2014;11:333-41.
Takazawa R, Kitayama S, Tsujii T. Successful outcome of flexible ureteroscopy with holmium laser lithotripsy for renal stones 2 cm or greater. Int J Urol 2012;19:264-7.
Cohen J, Cohen S, Grasso M. Ureteropyeloscopic treatment of large, complex intrarenal and proximal ureteral calculi. BJU Int 2013;111:E127-31.
[Figure 1], [Figure 2], [Figure 3], [Figure 4]
[Table 1], [Table 2], [Table 3], [Table 4]