Laparoscopic Ureterolithotomy as a Primary Modalityfor Large Proximal Ureteral Calculi:

Comparison to Rigid Ureteroscopic Pneumatic Lithotripsy

Young Hwii Ko, MD, PhD,1 Sung Gu Kang, MD,1 Jae Young Park, MD, PhD,1 Jae Hyun Bae, MD, PhD,1

Seok Ho Kang, MD, PhD,1 Dae Yeon Cho, MD, PhD,2 Hong Seok Park, MD, PhD,1 Jun Cheon, MD, PhD,1

Jeong Gu Lee, MD, PhD,1 and Je Jong Kim MD, PhD1

Abstract

Objective: To define the role of laparoscopic ureterolithotomy (LU) as a primary modality for large proximalureteral stones, we compared the outcomes of primary LU with those of ureterorenoscopy (URS), the currentlyestablished modality in this circumstance.Materials and Methods: Among 71 patients who underwent LU in our institution between February 2005 andJanuary 2010, 32 patients with stone size over 1.5 cm who underwent LU as a primary modality without priorshockwave lithotripsy or URS and for whom LU was conducted as a separate procedure were exclusivelyenrolled. Based on preoperative characteristics of patients and stones, this patient group was matched with theURS group (n¼ 32, rigid pneumatic lithotripter) during the same period.Results: The LU group and the URS group were similar in age, gender distribution, body mass index, stone size(18.1� 4.2 versus 17.9� 3.6 mm; P¼ .88), and stone location. Members of the LU group required a longeroperative time (118� 53 versus 59� 41 minutes; P< .001) and hospital stay (5.9� 2.1 versus 3.4� 2.4 days;P< .001) and had greater blood loss (155� 62 mL). However, stone clearance rate (no remnant stone in post-operative X-ray of the kidney, ureter, and bladder) in a single session was marginally higher in the LU group(93.8% versus 68.8%; P¼ .06). Total complication rate was not significant and was slightly higher in the URSgroup (12.5% versus 21.9%, P¼ .51). Stone migration into the kidney (n¼ 2 versus 5), ureteral perforation (n¼ 0versus 3), open conversion (n¼ 1 versus 2), and ureteral stricture (n¼ 1 versus 2), as long-term complications,occurred more frequently in the URS group.Conclusions: For large proximal ureteral stones, LU can be conducted safely as a first-line procedure withoutincrease of complication rate, compared with conventional URS. Although LU required a prolonged operativetime and a longer hospital stay and blood loss was greater, our data showed an advantage of LU in highclearance rate in a single procedure.

Introduction

Since the introduction of shockwave lithotripsy (SWL),followed by technical advancements in endoscopic ap-

proaches, including ureterorenoscopy (URS) and percutane-ous nephrolithotomy (PNL), surgical management of urinarystone disease has changed dramatically from an open ap-proach to a minimally invasive one.1 SWL and endourologicapproaches are highly successive and constitute the treatmentof choice for urinary calculi. However, SWL cannot be

recommended as the first-line option for management of largeureteral stones, particularly those located in the upper third ofthe ureter with severe hydronephrosis.2 For large ureteralcalculi, the reported success rate of URS as a single primaryprocedure with pneumatic lithotripsy is between 75% and90% in various series, making it the first option for treatmentof such calculi.3 However, about 7% of ureteral stones treatedwith endoscopic manipulation require retreatment and about1–10% of them require open surgery.4 Although the advent oflaser-based flexible ureteroscopes has revolutionized the

1Department of Urology, Korea University School of Medicine, Seoul, Korea.2Department of Urology, Inje University School of Medicine, Seoul, Korea.

JOURNAL OF LAPAROENDOSCOPIC & ADVANCED SURGICAL TECHNIQUESVolume 21, Number 1, 2011ª Mary Ann Liebert, Inc.DOI: 10.1089/lap.2010.0340

7

treatment of ureteral calculi, reporting successful stoneclearance of up to 98%,5 it requires additional equipment costand is thus not generalized currently as a rigid one.

Laparoscopic ureterolithotomy (LU) has recently emergedas a novel option for replacement of open surgery in themanagement of large proximal ureteral stones. Comparedwith open surgery, a stone can be nearly removed during oneprocedure using LU, while maintaining advantages over opensurgery in terms of analgesia, recuperation, hospital stay, andcosmetics.6 However, in most of the series using LU, the in-dication was restricted in selected circumstances. Most indi-cations were shared with that of open surgery, which isgenerally reserved as the final surgical modality. These in-clude failure with a prior SWL or endoscopic approach, large,impacted stones, or anatomic anomalies, which might requiresimultaneous surgical correction.1 From our experience withover 70 cases of LU, we recognized the potential of this mo-dality, combining the previously reported advantages of openand minimally invasive approaches. If these advantages weremanifested similarly for proximal large ureteral stones treatedwith LU as a primary surgical approach compared with URS,the current standard treatment of choice, the indication for LUcould be widened. However, lack of a large amount of com-parative data hinders our ability to reach a conclusion re-garding this issue. As a preliminary study, we present ourdata on LU compared with URS as a primary procedure.

Materials and Methods

Patients enrolled and data analysis

From February 2005 to January 2010, 71 LUs were con-ducted in our institution. The initial indication of LU in theinitial 30 cases was restricted to patients with prior failurewith URS or SWL, distal ureteral stricture, a large (more than1.0 cm), impacted stone, concomitant laparoscopic surgery fora separate indication, and social or economic necessity forstone removal in a single treatment session. Through theseexperiences, we recognized that LU can be conducted safelywithout open conversion while maintaining an acceptablesuccess rate in almost all cases. This encouraged us to care-fully expand our indications for LU from January 2007, as aprimary procedure for treatment of larger (more than 1.5 cm)upper to mid ureteral stones, if there is no absolute contra-indication for laparoscopic surgery. Before conducting LU, alltreatment options, including SWL, URS, and PLN, were pre-operatively explained and the final treatment decision wasmade based mainly on the preferences of surgeons and pa-tients after discussion of the advantages and disadvantages ofeach procedure. From retrospective reviews, 32 patients whochose LU as a primary treatment without prior history ofSWL, URS, or PNL, with stone size over 1.5 cm, and for whomLU was conducted as a separate laparoscopic procedure wereexclusively enrolled in this series. All patients who underwentLU at our institution were registered prospectively in a spe-cific database that included all important information, such asage, body mass index (BMI), stone location, size, and distancefrom the intrarenal pelvis. This allowed us to match the pa-rameters of patients who had undergone LU against those ofpatients who underwent URS during the same period. Forequal comparison of the two groups, match-paired analysiswas performed with respect to the entire variables mentionedabove.

Stone size, which was defined as the maximal diameter,and location of the stone were identified by abdominopelviccomputed tomography or intravenous pyelography (IVP) inall patients (Fig. 1A). Distance from the intrarenal pelvis inthis series was defined as the shortest distance from thetransverse line at the base of the intrarenal pelvis to the su-perior tip of the stone in an IVP or reconstructed coronal planeimage in cases of abdominopelvic computed tomography(Fig. 1B). Postoperative X-ray of the kidney, ureter, andbladder was taken on the day of surgery. For patients withLU, IVP was taken routinely at 3 months after surgery foridentification of dilated complications on the ureter. In theURS group, postoperative IVP was taken only if the patientcomplained of suspicious symptoms, including flank pain orunidentified fever.

Perioperative outcomes, including stone-free rate in a sin-gle session, operation time, and complications, were analyzedin the two groups. The stone-free rate in a single session,which is the primary end point in this series, was defined as ano residual stone on postoperative X-ray of the kidney, ureter,and bladder taken at 1 day after procedure. If a residual stonewas identified in a postoperative image, the case was thendesignated as a failure in this series, whether the identifiedstone was removed spontaneously or required axial proce-dures, including SWL or URS (Fig. 1C).

All data were collated using SPSS ver. 12.0 (SPSS, Chicago,IL) and evaluated by the Mann-Whitney U test, logistic re-gression test, and chi-square test. A P value of less than .05was considered statistically significant.

Operative technique

LU in this series was performed by five surgeons (D.Y.C.,J.H.B., S.H.K., Y.H.K, and J.Y.P.). All of the surgeons hadundergone a minimum of 2 years of training in a laparoscopicfellowship, and each surgeon was familiar with varioustransperitoneal or retroperitoneal laparoscopic urologic pro-cedures, including radical nephrectomy, partial nephrectomy,and marsupialization of renal cyst. All of these operators hadperformed a minimum of 10 LU procedures, among a total of71 cases. Before LU or URS procedure, susceptible antibioticswere applied based on urine culture report to diminish risk ofexposure to virulent bacteria. For prophylactic purposes, asingle dose of fluoroquinolone was administrated intrave-nously for all patients, 30 minutes before procedure.

LU was conducted using the conventional three laparo-scopic ports under flank position. Using a retroperitonealapproach, a 1.5-cm muscle-splitting incision was made be-tween the tip of the 12th rip and anterior superior illiacspine, depending on the location of the calculi. The perito-neum was pushed forward by an index finger, and a self-made expansion balloon was introduced into the space tocreate a working space. After insertion of a 10-mm Hassontrocar, the other two trocars (10 and 5 mm) were insertedunder laparoscopic vision, parallel to the first trocar in anequilateral triangle fashion. Using the transperitoneal ap-proach, the trocar for the camera was made on the peri-umbilicus; the positions of the other two trocars were thenadjusted depending on the location of the calculi for bettersurgical performance.

The ureter was generally identified on the major psoasmuscle. In an attempt to prevent migration of the calculi, ef-

8 KO ET AL.

forts were made to avoid touching the ureter directly, anddissection was carried out cephalocaudally, generally fromthe renal hilum. The location of the stone was identified by aconspicuous bulge on the ureter. Over the bulging of thestone, a longitudinal incision was made using a cold knife,and the stone was carefully extracted.

The ureter was then routinely catheterized using a standard6F Double-J stent that was closed at both ends. In earlier cases,it was inserted by the method described by Fan et al.7 Briefly,the Double-J stent was inserted into the bladder through theureteral incision site, with the help of a guidewire, which wasinserted through the one side hole of the stent. Followingremoval of the guidewire, the proximal end of the Double-J

stent was inserted into the renal pelvis through the incisionsite. From July 2008, we have applied the method originallydescribed by Khan and Khan.8 To facilitate the insertionprocedure by making it straight, a short guidewire, which was1 cm greater than the stent, was passed from the two sideholes of the stent, making the stent ‘‘V’’ shaped. This V-shapedstent was then inserted through the ureteral incision site; theguidewire was then removed. Using 4-0 vicryl, the incisionwas closed with three to four interrupted sutures. A drain wasinserted in all patients and removed routinely 2 days after LUafter confirmation of no urine leakage via check on draincreatinine level. The ureteral stent was extracted 2 weeks later,on an outpatient basis.

FIG. 1. Preoperative and postoperative images.(A) Preoperative intravenous pyelography image.In this scout film, white arrowhead indicates a leftureteral calculi measuring 1.6 cm in a 38-year-oldmale patient. (B) Intravenous pyelography of thesame patient. The distance to the upper pole of theureteral calculi from the intrarenal pelvis was26.4 mm (arrow line). (C) Postoperative X-ray of thekidney, ureter, and bladder taken after the day ofoperation shows a migrated stone in the left kidney(arrowhead). Because this case had failed to acquireno residual stone in a single session, it was desig-nated as failure in this series.

PRIMARY LU COMPARED WITH URS 9

URS was performed with a 7.5F semirigid ureteroscope,using a Swiss lighoclast (Richard Wolf) with a 2.4F, 668-mm-long probe. A Double-J stent was placed in patients with largeresidual stones, significant mucosal edema, stone impaction,or probable ureteral trauma.

Results

Preoperative characteristics are summarized in Table 1.Preoperatively, the LU and URS groups were similar in age,gender distribution, BMI, stone size, and location. During theprocedure, blood loss for LU, measured as the amount ofblood in the suction device, was 141� 24 mL. LU requiredmore operative time (118� 53 versus 59� 42 minutes;P< .001) and a longer hospital stay (5.9� 2.1 versus 3.4� 2.4days; P< .001). However, stone clearance rate in a singlesession was marginally higher in the LU group (93.8% versus68.8%; P¼ .06). In an attempt to identify factors affecting theclearance rate, several variables, including BMI, stone size,and distance from UPJ, were analyzed by logistic regression;however, none of these variables showed predictability(P¼ .98, 0.71, and 0.52, respectively).

Complications of each procedure are summarized inTable 2. Total complication rate was not significant and wasslightly higher in the URS group (12.5% versus 21.9%;P¼ .51). Stone migration into the kidney and ureteral perfo-ration occurred more frequently during URS. One patientrequired open conversion in LU because of stone migrationinto the kidney. In URS, 2 patients required open conversion,one for ureter perforation and another for migration of largestone fragments into the kidney. During a minimum follow-up period of 3 months, 1 and 2 patients with ureteral stricturewere found in each treatment group. Of them, 2 patients, 1from each group, required endoscopic dilatation at 4 and 5months after surgery, respectively.

Dividing the LU group into subgroups by the method ofapproach used, blood loss, stone clearance rate, hospital stay,ureteral catheterization period, and complication rates weresimilar (Table 3). However, the retroperitoneal subgroup re-quired more operative time than its retroperitoneal counter-part (128� 54 versus 92� 47 minutes; P< .04). Dividing bystenting method, blood loss and operative time were signifi-cantly shorter when the modified technique was used (Pvalue¼ .03 and< .001, respectively).

Discussion

Urinary calculi are the third most common affliction of theurinary tract; recurrence of the condition is observed in rou-tine urological practice.9 The advent of various new tech-niques, such as URS, SWL, and PNL, has revolutionized thetreatment of ureteral calculi and rendered a need for opensurgical lithotomy.10 Each treatment modality has particularrates of complete stone elimination, additional operationalrequirements, and complications. Currently, SWL and URShave become the standard treatments for ureteral calculi andoffer considerable advantages over conventional open ur-eterolithotomy.11 However, for larger ureteral stones over1.5 cm in maximal diameter, there is still controversy overwhich modality can obtain the best clearance, minimizingmorbidity in nature. Success of SWL in ureteral stone removalis dependent on the size of the stone; thus, the stone-free rateafter a single SWL session decreases from 84% to 42% whenthe stone is larger than 1.0 cm.12 For proximal ureteral stones,based on a promising stone-free rate in a single session, URS iscurrently established as the first choice.13 However, as themajority of upper ureteral stones were near the renal pelvis,the stones tend to be brushed easily into the renal pelvis,leading to URS surgical failure,14 particularly when a pneu-matic lithotripter was used. Currently, according to recentavailable guidelines, no clear-cut mention of treatment mo-dality was made when the size of the calculus is greater than1.0 cm.15 Although the 2007 AUA/EAU Ureteral StonesGuideline Panel reported that PNL is an acceptable first-linetreatment in selected cases with large, impacted stones in theupper ureter,16 it is associated with a relatively high morbidity

Table 1. Perioperative Outcomes

VariablesLaparoscopic

ureterolithotomy (n¼ 32)Ureterorenoscopy

(n¼ 32) P value

Age 50.7� 14.9 47.2� 12.1 .21Sex (M:F) 21:11 18:14 .60Body mass index (kg/m2) 25.3� 3.7 28.4� 7.2 .08Stone size (mm) 18.1� 4.2 17.9� 3.6 .88Stone side (right:left) 19:13 16:16 .61Stone location (upper:mid) 26:6 24:8 .76Distance of stone from intrarenal pelvis (mm) 36.9� 36.7 42.4� 37.8 .12Estimated blood loss (mL) 141� 24 — —Operative time (minute) 117.8� 53.1 58.8� 41.7 <.001Hospital day (day) 5.9� 2.1 3.4� 2.4 <.001Ureteral catheter indwelling period (day) 14.1� 3.1 7.3� 2.3 <.001Stone clearance rate in a single session 93.8% (30/32) 68.8% (22/32) .06

Table 2. Complications of Each Treatment Group

Complication

Laparoscopicureterolithotomy

(n¼ 32)Ureterorenoscopy

(n¼ 32)P

value

Open conversion n¼ 1 (3.1%) n¼ 2 (6.3%) 1.0Stone migration n¼ 2 (6.3%) n¼ 5 (15.6%) .43Ureteral perforation — n¼ 3 (9.4%) —Ureteral stricture n¼ 1 (3.1%) n¼ 2 (6.3%) 1.0

Total complicationrate

4/32 (12.5%) 7/32 (21.9%) .51

10 KO ET AL.

and a potentially large degree of bleeding, despite its highstone-free rate, because it requires access through the renalparenchyme.17

Although the advantages of LU as a treatment modality forlarge proximal ureteral stones have been reported, LU hasbeen used as a feasible alternative for treatment of these dif-ficult stones.18 Reported indication of LU includes a salvageprocedure for failed SWL or an endourologic approach, se-lected patients with large chronically impacted ureteralstones, a need for a concomitant laparoscopic operation for aseparate indication, and lack of the appropriate technologicalfacilities.19 However, these indications have not been clearlydefined and may vary from center to center depending on theavailable expertise. Indeed, because of excellent results withthe new endourologic technology, most data from developedcountries demonstrate a considerable population for whomLU is applied as a salvage procedure. In contrast, recent dataon LU as a primary procedure were mainly released in de-veloping countries, which do not have easy access to en-dourologic facilities and SWL.20,21 Considering this, to obtainthe actual benefit from the laparoscopic approach, we focusedon the patient group in whom LU was applied as a primaryprocedure, without prior trials using endoscopic or SWLtreatment.

As is evident from many clinical series, the greatest ad-vantage of LU is the high probability of removing a largestone in one session without need for additional procedures.A success rate of greater than 95% has been described byvarious researchers,22 and it was also regenerated in our data.This benefit can be particularly maximized for patients with asolitary kidney or functional renal disease, or a social or eco-nomic necessity for stone removal in a single treatment ses-sion. This high success rate, which is comparable with that ofURS using a laser, can be advocated in centers where a facilitywith laser equipment is not available or in centers where ur-eteroscopy devices are not readily available. In contrast, lap-aroscopy is currently available at many centers, which makesit an alternative option than the endoscopic approach.23 InSWL, retreatment is necessary in up to 36% of patients,24 andauxiliary procedures, including ureteral catheter insertion orendoscopic manipulation, are required in about 46% of cases.3

Particularly large proximal stones also pose a significantchallenge for modern endoscopic techniques, often requiringseveral endoscopic procedures.3 For stone fragments brushedinto the renal pelvis, acceptance of SWL as a further treatmentremains to be obtained.25

Although obvious advantages are associated with a highsuccess rate, a general reluctance still exists with regard to useof LU for larger upper ureteral stones,26 mainly because ofprolonged operative time and EBL, compared with URS.Disadvantages of laparoscopy also include a longer hospitalstay, risk of injury to intra-abdominal structures inherent inthe laparoscopic approach, and the inherited risk of conver-sion to open surgery. Regarding this point, our data showhow the surgical outcome of LU can be improved. In theconduct of LU, the access can be carried out via the trans-peritoneal or retroperitoneal approach. The retroperitonealapproach has advantages over transperitoneal access by ob-viating compromise of the peritoneum and mobilizing theviscera, which could reduce the occurrence of complica-tions.27 However, the retroperitoneal approach offers a lim-ited working place and finding the ureter is often difficult

Ta

bl

e3.

Co

mp

ar

iso

nD

ep

en

ds

on

th

eM

et

ho

do

fA

pp

ro

ac

ha

nd

th

eS

te

nt

in

gM

et

ho

d

Met

hod

ofap

pro

ach

Dou

ble-

Jin

sert

ion

met

hod

Tot

alT

ran

sper

iton

eal

(n¼

16

)R

etro

per

iton

eal

(n¼

16

)P

val

ue

Sta

nd

ard

tech

niq

ue

(20

)M

odifi

edte

chn

iqu

e(1

2)

Pv

alu

e

EB

L(m

L)

141�

2414

9�

2313

8�

270.

6315

2�

3899�

640.

03O

per

ativ

eti

me

(min

ute

s)11

8�

5392�

4712

8�

540.

0413

4�

5072�

31<

0.00

1

Sto

ne

clea

ran

cera

tein

asi

ng

lese

ssio

n93

.8%

(30/

32)

93.8

%(1

5/16

)93

.8%

(15/

16)

—95

%(1

9/20

)91

.6%

(11/

12)

—

Ho

spit

alst

ay(d

ays)

5.9�

2.1

5.7�

1.7

6.3�

2.7

0.62

6.2�

3.0

5.1�

2.1

0.3

Co

mp

lica

tio

nra

te4/

32(1

2.5%

)12

.5%

(2/

16)

1S

ton

em

igra

tio

n1

Ure

tera

lst

rict

ure

12.5

%(2

/16

)1

Op

enco

nv

ersi

on

1S

ton

em

igra

tio

n

—10

%(2

/20

)1

Sto

ne

mig

rati

on

1U

rete

ral

stri

ctu

re

16.6

%(2

/12

)1

Op

enco

nv

ersi

on

1S

ton

em

igra

tio

n

0.62

PRIMARY LU COMPARED WITH URS 11

because of lack of anatomical landmarks. In fact, Harewoodet al.28 reported in their series that two of three retroperitonealapproach cases were converted to transperitoneal laparos-copy because of a limited working place. In a prospectivestudy29 comparing transperitoneal and retroperitoneal ap-proaches during the learning curve, significant differenceswere demonstrated in favor of the transperitoneal procedurein terms of time for access to the operating field, time forsuturing of the ureter, and total operative time. Similar tothese observations, the transperitoneal approach in our seriesrequired significantly less operative time than the transper-itoneal approach, with the same complication rate.

Post-LU stenting of the ureter is mandatory if the morbidityof the procedure has to be kept low. However, one of thedifficulties encountered during this procedure is the place-ment of a stent after stone extraction, which, in our experience,was the most time-consuming procedure. The standardDouble-J stent is soft and pliable and curls at both ends be-cause of inherent memory, necessitating both great expertiseand considerable patience to ensure its placement in the cor-rect position inside the ureter. However, placement of thestent by the standard technique also adds considerably tothe operating time. Gaur et al.30 reported a mean operatingtime of 92 minutes when the ureter was stented and su-tured and only 66 minutes when the ureter was left open.Moreover, the narrow space of the retroperitoneal cavitymade it difficult to operate when the Double-J stent twisted inthe operating field. To facilitate this procedure, modificationsto standard stenting techniques have been invented by severalauthors.7,8 By application of those methods, we observedobvious improvement in terms of operative time and bloodloss.

We recognized several limitations in this study. The firstdrawback is that the data were collected from different sur-geons without randomization. LU procedures were per-formed by five different surgeons with different surgicalexperience. This difference in cases of LU may affect thelearning curve of each surgeon, resulting in a difference inoperative time, blood loss, and complication rate. In addition,considering the relatively small number of cases with primaryLU, it was not possible to perform a randomized study. Sec-ond, the relatively high complication rate in the pneumaticURS group in this series should be interpreted with care.Along with advances in the flexible URS, its ability to accessthe upper urinary tract, combined with laser-based litho-tripsy, particularly using holmium YAG laser, made theflexible ureteroscopic laser lithotripsy more attractive to treatcomplicated ureteral stones with high success rate and lowmorbidity. Although stone size and location were variable,considering reported stone-free rates over 90%31,32 and com-plication rates below 10%,31,33 this novel device may offer amore effective and definitive treatment. In particular, stonemigration, which was the most common complication ofpneumatic URS in this series, may be reduced using the flex-ible URS with laser lithotripsy. Finally, the prolonged patienthospitalization of 3.4 days in the URS group compared withthat of other published data deserves to be explained here.This prolongation is mainly caused by the characteristics ofKorean Health Care system, which is national and mandatory.Because of this national coverage, the hospital admission costcan be maintained at a minimum compared with the costs ofother nations; therefore, the patients and doctors alike are not

aggressive in scheduling an early discharge. Despite theselimitations, our data show that LU may be considered as thefirst-line management for large impacted ureteric stones, es-pecially to ensure that patients become stone-free within asingle operation. Prospective, randomized trials comparingthese modalities for treatment of large ureteric calculi mayprove the efficacy of one modality over the other.

Conclusions

For large proximal ureteral stones, LU as a primary pro-cedure can be conducted safely as a first-line procedurewithout increase of complication rate, compared with theconventional URS. Although LU required a prolonged oper-ative time, greater blood loss, and a longer hospital stay, op-erative time can be decreased by application of atransperitoneal approach and modification of the stentingmethod. Our data show an advantage of LU regarding highclearance rate in a single procedure, implying its clinical ef-ficacy particularly in the absence of flexible ureteroscopes orlaser-based lithotropic equipments.

Disclosure Statement

No competing financial interest exists.

References

1. Paik ML, Wainstein MA, Spirnak JP, et al. Current indica-tions for open stone surgery in the treatment of renal andureteral calculi. J Urol 1998;159:374–378.

2. Lee YH, Tsai JY, Jiaan BP, et al. Prospective randomized trialcomparing shock wave lithotripsy and ureteroscopic litho-tripsy for management of large upper third ureteral stones.Urology 2006;67:480–484.

3. Keeley FX, Gialas I, Pillai M, et al. Laparoscopic ureter-olithotomy: the Edinburgh experience. BJU Int 1999;84:765–769.

4. El-Moula MG, Abdallah A, El-Anany F, et al. Laparoscopicureterolithotomy: our experience with 74 cases. Int J Urol2008;15:593–597.

5. Muslumanoglu AY, Karadag MA, Tefekli AH, et al. When isopen ureterolithotomy indicated for the treatment of ureteralstones? Int J Urol 2006;13:1385–1388.

6. Goel A, Hemal AK. Upper and mid-ureteric stones: a pro-spective unrandomized comparison of retroperitoneoscopicand open ureterolithotomy. BJU Int 2001;88:679–682.

7. Fan T, Xian P, Yang L, Liu Y, et al. Experience and learningcurve of retroperitoneal laparoscopic ureterolithotomy forupper ureteral calculi. J Endourol 2009;23:1867–1870.

8. Khan M, Khan F. Innovative technique for ureteral stentingduring retroperitoneal laparoscopic ureterolithotomy. J En-dourol 2005;19:994–996.

9. Bartoletti R, Cai T, Mondaini N, et al. Epidemiology and riskfactors in urolithiasis. Urol Int 2007;79:3–7.

10. Jeong BC, Park HK, Byeon SS, et al. Retroperitoneal lapa-roscopic ureterolithotomy for upper ureter stones. J KoreanMed Sci 2006;21:441–444.

11. Preminger GM, Tiselius HG, Assimos DG, et al. AmericanUrological Association Education and Research, Inc.; Euro-pean Association of Urology. Guideline for the managementof ureteral calculi. Eur Urol 2007;52:1610–1631.

12. Park H, Park M, Park T. Two-year experience with ureteralstones: extracorporeal shockwave lithotripsy v ureteroscopicmanipulation. J Endourol 1998;12:501–504.

12 KO ET AL.

13. Chen CS, Wu CF, Shee JJ, et al. Holmium:YAG Lasertripsywith semirigid ureterorenoscope for upper-ureteral stones>2 cm. J Endourol 2005;19:780–784.

14. Fong YK, Ho SH, Peh OH, et al. Extracorporeal shockwavelithotripsy and intracorporeal lithotripsy for proximal ure-teric calculi—a comparative assessment of efficacy andsafety. Ann Acad Med Singapore 2004;33:80–83.

15. Segura JW, Preminger GM, Assimos DG, et al. UreteralStones Clinical Guidelines Panel summary report on themanagement of ureteral calculi. The American UrologicalAssociation. J Urol 1997;158:1915–1921.

16. Preminger GM, Tiselius HG, Assimos DG, et al. EAU/AUANephrolithiasis Guideline Panel. Guideline for the manage-ment of ureteral calculi. J Urol 2007;178:2418–2434.

17. Kurien A, Baishya R, Mishra S, et al. The impact of percu-taneous nephrolithotomy in patients with chronic kidneydisease. J Endourol 2009;23:1403–1407.

18. Sinha R, Sharma N. Retroperitoneal laparoscopic manage-ment of urolithiasis. J Laparoendosc Adv Surg Tech A1997;7:95–98.

19. Skolarikos A, Papatsoris AG, Albanis S, et al. Laparoscopicurinary stone surgery: an updated evidence-based review.Urol Res 2010;38:337–344.

20. Gaur DD, Agarwal DK, Purohit KC, et al. Retroperitoneallaparoscopic pyelolithotomy. J Urol 1994;151:927–929.

21. Nualyong C, Taweemonkongsap T. Laparoscopic ureter-olithotomy for upper ureteric calculi. J Med Assoc Thai1999;82:1028–1033.

22. Kijvikai K, Patcharatrakul S. Laparoscopic ureterolithotomy:its role and some controversial technical considerations. Int JUrol 2006;13:206–210.

23. Khaladkar S, Modi J, Bhansali M, et al. Which is the bestoption to treat large (>1.5 cm) midureteric calculi? J Lapar-oendosc Adv Surg Tech A 2009;19:501–504.

24. El-Moula MG, Abdallah A, El-Anany F, et al. Laparoscopicureterolithotomy: our experience with 74 cases. Int J Urol2008;15:593–597.

25. Wang Y, Hou J, Wen D, et al. Comparative analysis of upperureteral stones (>15 mm) treated with retroperitoneoscopicureterolithotomy and ureteroscopic pneumatic lithotripsy.Int Urol Nephrol 2010 [Epub ahead of print].

26. Wu CF, Shee JJ, Lin WY, et al. Comparison betweenextracorporeal shock wave lithotripsy and semirigid ur-

eterorenoscope with holmium:YAG laser lithotripsy fortreating large proximal ureteral stones. J Urol 2004;172:1899–1902.

27. Kieran K, Montgomery JS, Daignault S, et al. Comparison ofintraoperative parameters and perioperative complica-tions of retroperitoneal and transperitoneal approaches tolaparoscopic partial nephrectomy: support for a retroperi-toneal approach in selected patients. J Endourol 2007;21:754–759.

28. Harewood LM, Webb DR, Pope AJ. Laparoscopic ureter-olithotomy: the results of an initial series, and an evaluationof its role in the management of ureteric calculi. Br J Urol1994;74:170–176.

29. Bove P, Micali S, Miano R, et al. Laparoscopic uretero-lithotomy: a comparison between the transperitoneal andthe retroperitoneal approach during the learning curve.J Endourol 2009;23:953–957.

30. Guar DD, Trivedi S, Prabhudesai MR, et al. Laparoscopicureterolithotomy: Technical considerations and long termfollow up. Eur Urol 2001;40:609–613.

31. Cocuzza M, Colombo JR Jr., Cocuzza AL, et al. Outcomesof flexible ureteroscopic lithotripsy with holmium laserfor upper urinary tract calculi. Int Braz J Urol 2008;34:143–149.

32. Portis AJ, Rygwall R, Holtz C, et al. Ureteroscopic laserlithotripsy for upper urinary tract calculi with active frag-ment extraction and computerized tomography followup. JUrol 2006;175:2129–2133.

33. Cocuzza M, Colombo JR Jr., Ganpule A, et al. Combinedretrograde flexible ureteroscopic lithotripsy with holmiumYAG laser for renal calculi associated with ipsilateral ure-teral stones. J Endourol 2009;23:253–257.

Address correspondence to:Hong Seok Park, MD, PhD

Department of UrologyKorea University School of Medicine

Anam-dong 5-ga, Seongbuk-guSeoul 136-705

Korea

E-mail: urokyh@korea.ac.kr

PRIMARY LU COMPARED WITH URS 13

Copyright of Journal of Laparoendoscopic & Advanced Surgical Techniques is the property of Mary Ann

Liebert, Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the

copyright holder's express written permission. However, users may print, download, or email articles for

individual use.