Endourology and Stones

Comparison of Different Ureteroscope Sizes inTreating Ureteral Calculi in Adult PatientsGokhan Atis, Ozgur Arikan, Cenk Gurbuz, Asıf Yildirim, B€ulent Erol, Sabri Pelit, Ismail Ulus,and Turhan Caskurlu

OBJECTIVE To compare the success and complication rates of a 4.5-6.5F semirigid ureteroscope (S-URS) with

Financial Disclosure: The authoFrom the Department of Urolo

and Research Hospital, Istanbul,Reprint requests: Gokhan Atis

University, Goztepe Training andAtasehir, Istanbul, Turkey. E-mSubmitted: March 16, 2013,

ª 2013 Elsevier Inc.All Rights Reserved

an 8.5-11.5F S-URS in treating ureteral stones in adult patients.

MATERIALS ANDMETHODS

Fifty-two patients with ureteral stones, who were treated with 4.5-6.5F S-URS (group 1) and 52patients who were treated with 8.5-11.5F S-URS (group 2) were compared retrospectively using

a matched-pair analysis. The size, lateralization, location, and impaction of the stones and also thepatient age, gender, body mass index, and the presence of hydronephrosis were used as thematching parameters. The stones were fragmented with Holmium-YAG laser.

RESULTS The matching parameters were comparable between the 2 groups. The stone-free rates were

88.5% in group 1 and 84.6% in group 2 (P ¼ .566) after a single procedure. The mean operativetimes for groups 1 and 2 were 32.7 � 5.8 and 30.2 � 5.4 minutes, respectively (P ¼ .06).Postoperative hematuria was detected in 1.9% and 13.5% of patients in groups 1 and 2 (P ¼.027). Ureteral balloon dilation was needed in 1.9% and 15.4% of patients in groups 1 and 2,respectively (P ¼ .015). Mucosal injury was observed in 1.9% and 13.5% of the patients in groups1 and 2, respectively (P ¼ .027). No major complications were noted in either group.

CONCLUSION Although the stone-free rates and operative times were similar between the 2 groups, a 4.5-6.5F

ureteroscope can reduce the need for ureteral balloon dilation and some minor complications, suchas mucosal injury and postoperative hematuria, in adult patients. UROLOGY 82: 1231e1235,2013. � 2013 Elsevier Inc.

lthough ureteroscopy (URS) is a widely usedmethod in treating ureteral stones, the proce-

Adure might be associated with some complica-

tions. The reported overall complication rate of URSvaries from 9% to 25%.1-6 Intraoperative complications ofURS include mucosal injury (1.5%), ureteral perforation(1.7%), significant bleeding (0.1%), and ureteral avulsion(0.1%).2 Early complications, such as fever or urosepsis(1.1%), persistent hematuria (2%), and renal colic(2.2%), might also be observed after this procedure.2 Therate of late URS complications has been reported as 0.1%for ureteral stricture and 0.1% for vesicoureteral reflux.2

Most of these complications have been associated withlarger instrument size, and the complication rate forureteroscopic procedures reportedly decreases with theuse of small-caliber ureteroscopes.7,8 The overall com-plication rate has been reported to decrease from 5% to9% with the use of small ureteroscopes.7,8

Although some investigators have compared the safetyand efficacy of 4.5-6.5F semirigid ureteroscopes (S-URS)

rs declare that they have no relevant financial interests.gy, Istanbul Medeniyet University, Goztepe TrainingTurkey, M.D., Department of Urology, Istanbul MedeniyetResearch Hospital, Tahrali Sitesi Safakyeli Apt. D:36ail: gokhanatis@hotmail.comaccepted (with revisions): July 11, 2013

h

with the larger size of ureteroscopes in children, none ofthe studies has compared these instruments in adultpatients.9,10 To our knowledge, the use of small caliberof ureteroscopes might be associated with reducedcomplication rates, even in adult patients. To test thishypothesis, we compared the efficacy and safety of4.5-6.5F S-URS with 8.5-11.5F S-URS in treatingureteral stones in adult patients.

MATERIALS AND METHODS

Between March 2012 and October 2012, 52 patients withureteral stones were treated with 4.5-6.5F S-URS (Wolf,Knittlingen, Germany; group 1), which is the only availableureteroscope at that period in our clinic. The patient out-comes were compared with 52 patients retrospectively, whowere selected from a group of 352 patients and treated with8.5-11.5F S-URS (Wolf, Knittlingen, Germany) betweenFebruary 2011 and February 2012, using a matched-pair analysis(group 2) at a 1:1 ratio. The matching parameters were the size,lateralization, location, and impaction of the stones and alsothe patient age, gender, body mass index, and the presence ofhydronephrosis. The impaction of the stone was defined as thefailure of the guidewire passage behind the stone.The patients were preoperatively evaluated with plain

abdominal radiography, intravenous urogram, and/or non-contrast computed tomography (NCCT). The mean stone sizewas determined as the longest diameter on plain abdominal

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Table 1. Matched-pair analysis of the groups

Variables Group 1 (4.5-6.5F; n ¼ 52) Group 2 (8.5-11.5F; n ¼ 52) P Value

Age (y) 43.7 � 11.2 44.2 � 12.1 .820Male/female 28/24 30/22 .693BMI (kg/m2) 26.54 � 3.49 27.40 � 3.31 .112Stone size (mm) 11.5 � 2.5 12.2 � 2.2 .159Lateralization 27/25 24/28 .556Stone location .892Upper ureter (n, %) 13 (25) 11 (21.2)Midureter (n, %) 11 (21.2) 12 (23.1)Lower ureter (n, %) 28 (53.8) 29 (55.7)

Preoperative hydronephrosis (n, %) 32 (61.5) 34 (65.4) .684Stone impaction (n, %) 6 (11.5) 7 (13.5) .767

BMI, body mass index; F, French.

radiography for opaque stones and on NCCT for nonopaquestones. Laboratory tests, such as urinalysis, urine culture, coag-ulation screen tests, and serum creatinine level, were assessedbefore the surgery, and the patients who had positive urinecultures were treated with appropriate antibiotics before thesurgery. First-generation cephalosporins were administered forprophylaxis in all patients before the surgery. The patients withmultiple stones, presented cases, pediatric patients, and patientswith abnormal anatomies, such as horseshoe or pelvic kidney,were excluded from the study.

All the procedures were performed under general anesthesiaby 1 of the 3 experienced surgeons, with the patients placed inthe lithotomy position. The same technique was performed foreach of the groups. At the beginning of the procedure, theureteroscope was introduced into the bladder to localize theureteral orifice and place hydrophilic guidewire into the ureter.The S-URS was then introduced into the ureter. If the ure-teroscope failed to be introduced into the ureter, the ureteralorifice was dilated with balloon dilators. In cases, in which theureteroscope failed to reach to the stones because of the inabilityto introduce the ureteroscope into the ureter or the migration ofthe stone, a Double-J stent was placed, and the procedure wasrepeated 2 weeks later. The stones were fragmented withHolmium-YAG laser in all procedures, with an energy level0.6-1.0 J and a frequency at 5-10 Hz. Some stone fragments wereremoved with basket catheter for stone analysis. At the endof the procedure, a Double-J stent was placed in selected casesaccording to the duration of the procedure or presence ofureteral trauma.

All the patients were followed up with imaging studies, suchas plain abdominal radiography and urinary ultrasonography, todetect the presence of hydronephrosis and residual stone frag-ments on postoperative day 1 and 1 month after the surgery.NCCT was performed only on the patients with nonopaquestones. Treatment success was defined as complete stonedisappearance in plain radiography or NCCT, which was per-formed 1 month after the surgery.

Both the groups were compared with respect to operativetime, the need for balloon dilation, stone migration rates,postoperative stent placement, stone-free rates (SFRs), length ofhospital stay, and auxiliary procedure and complication rates.

Statistical AnalysisStatistical analyses were performed with SPSS software, version20.0 (IBM, Armonk, NY). Data were determined as mean �SDs or frequency. The Kolmogorov-Smirnov test was performed

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to test normal distribution. Categorical variables were analyzedusing the chi-squared test or Fisher’s exact test, according to theresults of the Kolmogorov-Smirnov test. Continuous variableswere compared with an unpaired t test or the Mann-WhitneyU test. A P value �.05 was considered to be significant.

RESULTSThe demographic data were comparable between the 2groups in terms of the size, lateralization, location, andimpaction of the stones and also the patient age, gender,body mass index, and the presence of hydronephrosis(Table 1).

The operative and postoperative outcomes of patientsin each group are shown in Table 2. The mean operativetimes were 32.7 � 5.8 minutes in group 1 and 30.2 �5.4 minutes in group 2 (P ¼ .06). Ureteral balloon dila-tion was needed in 1 patient (1.9%) in group 1 and in 8patients (15.4%) in group 2 (P ¼ .015).

The complications were classified using the Claviensystem.11 The observed complications were fever (Clav-ien 1), hematuria (Clavien 1), renal colic (Clavien 1),mucosal injury (Clavien 1), stone migration (Clavien 3),inability to introduce the URS (Clavien 3), and thepresence of the residual fragments that require additionaltreatment (Clavien 3). Six patients (11.5%) in group 1experienced 13 complications, whereas 9 patients(17.3%) in group 2 experienced 28 complications (P ¼.085). Although the number of patients who experiencedany of the complications was higher in group 2, thedifference was not statistically significant (Table 3).

Stone migration was detected in 2 patients in group 1and 3 patients in group 2 (3.8% in group 1 and 5.8% ingroup 2; P ¼ .647). In these patients, a Double-J stent wasplaced, and auxiliary procedures, such as shock-wavelithotripsy, retrograde intrarenal surgery, or re-URS,were performed. In group 1, reaching to the stone wasnot possible because of the inability to introduce theS-URS owing to the ureteral kinking or stenosis in 1patient (1.9%), whereas this rate was 5.8% (3 patients) ingroup 2 (P ¼ .117). In these patients, a Double-J stentwas placed, and the procedure was repeated 2 weeks laterwith the same ureteroscope. In the follow-up, residualstone fragments were detected in 3 patients (5.8%) in

UROLOGY 82 (6), 2013

Table 2. The operative and postoperative outcomes of the groups

Variables Group 1 (4.5-6.5F; n ¼ 52) Group 2 (8.5-11.5F; n ¼ 52) P Value

Operative time (min) 32.7 � 5.8 30.2 � 5.4 .06Balloon dilation (n, %) 1 (1.9) 8 (15.4) .015Stent placement (n, %) 11 (21.2) 13 (25) .642Auxillary procedure (n, %) 6 (11.5) 8 (15.4) .42SFR after a single procedure (n/total; %) 46/52 (88.5) 44/52 (84.6) .566Length of hospital stay (d) 1.15 � 0.64 1.21 � 0.74 .696

SFR, stone-free rate; other abbreviation as in Table 1.

Table 3. The intraoperative and postoperative complications

Variables Group 1 (4.5-6.5F, n ¼ 52) Group 2 (8.5-11.5F, n ¼ 52) P Value

Complication rate (number of patients, %) 6 (11.5%) 9 (17.3) .085Fever (n, %) 3 (5.8) 3 (5.8) 1.000Hematuria (n, %) 1 (1.9) 7 (13.5) .027Renal colic (n, %) 2 (3.8) 3 (5.8) .647Mucosal injury (n, %) 1 (1.9) 7 (13.5) .027Stone migration (n, %) 2 (3.8) 3 (5.8) .647Inability to introduce the URS (n, %) 1 (1.9) 3 (5.8) .112Residual fragments (n, %) 3 (5.8) 2 (3.8) .647

URS, ureteroscopy; other abbreviation as in Table 1.

group 1 and 2 patients (3.8%) in group 2 (P ¼ .647). Inthese patients, re-URS was performed 1 month after thesurgery. In total, after a single procedure, 46 patients(88.5%) in group 1 and 44 patients (84.6%) in group 2(P ¼ .566) were rendered stone-free. The overall SFRswere 100% after auxiliary treatments in each group.

Postoperative fever was observed in 3 patients (5.8%)in either group (P ¼ 1.000) and treated with antibiotics.Postoperative renal colic was observed in 2 patients(3.8%) in group 1 and 3 patients (5.8%) in group 2 (P ¼.647) and was treated with analgesics and hydration.Intraoperative mucosal injuries were observed in 1.9% ofthe patients in group 1 and 13.5% of the patients in group2 (P ¼ .027). A Double-J stent was placed in thesepatients and removed 2 weeks after the surgery. Post-operative hematuria was detected in 1 patient (1.9%) ingroup 1 and 7 patients (13.5%) in group 2 (P ¼ .027) andwas treated with hydration. Neither ureteral perforationnor ureteral avulsion was noted in either group (Table 3).

The stone analyses in the groups were performed in 42patients (80.7%) in group 1 and 44 patients (84.6%)in group 2 and revealed the following results: group 1,Ca-oxalate (86.5%), cystine (1.9%), struvite (3.8%),and uric acid (7.7%); group 2, Ca-oxalate (84.6%),cystine (1.9%), struvite (7.7%), and uric acid (5.8%).

COMMENTS-URS is the most preferred management choice intreating ureteral calculi worldwide. The reported SFR forS-URS in treating ureteral calculi varies from 85% to100% according to the stone location.12,13 Despite thishigh success rate, the procedure has been associatedwith a complication rate of 9%-25%.14 Although mostof these complications are minor and can be treated

UROLOGY 82 (6), 2013

conservatively, some major complications, such asureteral perforation or avulsion, may also be observedafter this procedure.14 However, it has been reported thatthe complication rate after S-URS decreases to 5%-9%with the use of small-caliber ureteroscopes.7,8 Note thatthe safety and efficacy of 4.5-6.5F S-URS have neverbeen examined in ureteral stone treatments for adultpatients, which is known to use the smallest S-URSequipment worldwide, with a 3.3F working channel.10

After introducing this instrument in our clinic, wetreated 52 patients for ureteral calculi with this instru-ment and matched this group with 52 patients (selectedfrom a group of 352 patients) who were treated with 8.5-11.5F S-URS and compared the safety and efficacy ofeach ureteroscope. According to our findings, in treatingureteral stones, 4.5-6.5F S-URS presented lower rates ofureteral injury and postoperative hematuria and similarSFRs and reduced the need for balloon dilation comparedwith 8.5-11.5F S-URS.

The factors predicting unfavorable results of S-URS intreating ureteral stones have been studied by severalinvestigators. El-Nahas et al15 reported a complicationrate of 6.7% and an SFR of 87% after a single uretero-scopic procedure. In their study, proximal ureteral stones,low experience in URS, stone width, and stone impactionwere determined to be significant factors that contributedto unfavorable results. Similarly, Seitz et al16 achieveda success rate of 90.6% and a complication rate of 5.5% in543 patients who were treated with URS for ureteralstones. In that study, proximal ureteral stones were asso-ciated with increased intraoperative complication andretreatment rates. The caliber of ureteroscopes has alsobeen associated with unfavorable results after URS by thesame investigators. Yaycioglu et al17 compared the 7.5Fureteroscope with the 10F rigid ureteroscope and reported

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that the stone-free and complication rates improvedwith the 7.5F ureteroscope in treating ureteral calculi.Similarly, Francesca et al18 revealed that the small caliberS-URS was safer compared with the rigid ureteroscopes.In the present study, we achieved a SFR of 88.5% with4.5-6.5F S-URS and a SFR of 84.6% with 8.5-11.5F S-URS after a single intervention; these resultswere similar to the results in published reports regardingSFRs after URS. The SFRs were similar among the 2groups. However, the complication rates in the presentstudy were 11.5% for 4.5-6.5F S-URS and 17.3% for8.5-11.5F S-URS. Our complication rates were also inaccordance with published series that were conductedwith a large number of patients.15,16,19,20 The number ofpatients who experienced any of the complications wasgreater in the 8.5-11.5F S-URS group, although it failedto reach statistical significance.

Stone migrations, the inability to reach the stone, andresidual stone fragments are potential complications ofURS. In the present study, the stone migration rates were3.8% in the 4.5-6.5F S-URS group and 5.8% in the 8.5-11.5F S-URS group. The inability to reach the stone wasobserved in 1.9% of patients in the 4.5-6.5F S-URS groupand 5.8% in the 8.5-11.5F S-URS group. Residual stonefragments were detected in 5.8% of the patients in the 4.5-6.5F S-URS group and 3.8% of patients in the 8.5-11.5F S-URS group. These complication rates were similarbetween the 2 groups. El-Nahas et al15 reported a stonemigration rate of 3.5%, a failure rate of 1.3%, and residualfragments rates of 8% after S-URS procedures for ureteralstones; these rates are similar to those in the present study.It has been suggested that stone migration in URS can bedecreased using a laser lithotripter and other devices, suchas occlusion balloon catheters or stone cones.20 Althoughwe used laser lithotripsy in all the procedures, stone coneor occlusion balloon catheters were not used to preventstone migration because of the cost involved.

In the present study, mucosal injury and hematuriawere the most common complications in the 8.5-11.5FS-URS group. Similar to our results, these complicationshave been reported as the most common complicationsafter URS by some investigators.20-22 Mucosal injury wasobserved in 13.5% of the patients in the 8.5-11.5FS-URS group and 1.9% of the patients in the 4.5-6.5F S-URS group, which reached the level of statisticalsignificance (P ¼ .027). In each group, the patients whoexperienced mucosal injury were treated with Double-Jstent placement. However, postoperative hematuria wasnoted in the patients with mucosal injury, and this sideeffect responded to hydration. To our knowledge, thesecommon complications can be reduced with the use ofsmall-caliber ureteroscopes.

Balloon dilators have been traditionally used to facili-tate the introduction of the ureteroscope into the ureterand to treat ureteral strictures.23 Bin et al23 noted thatintraoperative balloon dilation was needed in 27.5% ofpatients who have undergone URS with S-URS rangingfrom 6.5F to 8F to treat ureteral stones. In our study

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group, balloon dilation of the ureteral orifice was neededin 13.5% of the patients in 8.5-11.5F S-URS group,whereas this rate was only 1.9% in the 4.5-6.5F S-URSgroup (P ¼ .027). To our knowledge, the need forballoon dilation of the ureteral orifice can be reducedusing small caliber ureteroscopes. This method also hasthe advantage of being cost-effective. Moreover, concernsstill exist about developing ureteral stricture after balloondilation in ureteroscopic procedures. However, in ourstudy, none of the patients who underwent balloondilation experienced hydronephrosis 1 month after thesurgery, which may have indicated ureteral stricture.

A disadvantage of 4.5-6.5F S-URS could be that thisinstrument has only 1 working channel of 3.3F, whereas8.5-11.5F S-URS has 2 working channels of 6.6F, whichresult in a faster irrigation flow, larger field of view, andbetter visibility. Despite these advantages of 8.5-11.5F S-URS, we did not observe any statistical differencesbetween the groups in terms of the operative time and theSFR.

The present study has some limitations. First, the studywas retrospective and in nonrandomized design in natureand has limited power for statistical analysis, which maylack detecting some differences between the groups.Second, postoperative SFRs were evaluated with NCCTonly in the patients with nonopaque calculi, which mayhave resulted in higher SFRs. Despite these limitations,our study was the first to compare the 4.5-6.5F S-URSand 8.5-11.5F S-URS in adult patients.

CONCLUSIONIn the present study, the SFRs and operative times weresimilar between the 2 groups. However, 4.5-6.5F S-URScan reduce the need for ureteral balloon dilation andsome minor complications, such as ureteral mucosalinjury and postoperative hematuria, in adult patients.

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