Ureteroscopy || Ureteral Stenting or No Stenting

341M. Monga (ed.), Ureteroscopy: Indications, Instrumentation & Technique, Current Clinical Urology,DOI 10.1007/978-1-62703-206-3_29, © Springer Science+Business Media New York 2013

Introduction

Ureteroscopy has come to the forefront in the surgical management of ureteral calculi. There is signi fi cant literature regarding the effectiveness of this modality in clearing stones from the ureter; however, there still remains an active debate regarding the placement of ureteral stents after ureteroscopy. The morbidity of a stent, the resources required for an additional procedure to remove it, as well as the growing body of literature suggesting stentless ureteroscopy is a reasonable option, make it worthwhile to ask when stenting is necessary for optimal surgical outcome and patient care.

What Do Urologists Do?

A survey sent to community and academic urolo-gists to assess the use of ureteral stenting after ureteroscopy for stone surgery was performed demonstrating signi fi cant variety in the practice patterns among urologists [ 1 ] . Of the 173 respon-dents, 97% thought patient tolerance of stent dis-comfort was the most signi fi cant issue with indwelling ureteral stents. Approximately 66% of urologists placed a ureteral stent more than 50% of the time after routine ureteroscopy, with 13% of the respondents placing stents 100% of the time. Interestingly 25% of respondents stated that an access sheath would change their use of stents—i.e., 29% would increase their use of stenting and surprisingly 71% would decrease their use of stenting. Half of urologists would place a ureteral stent 100% of the time, if the ure-teral ori fi ce was dilated (balloon or coaxial dila-tor). Despite accumulating evidence suggesting that ureteral stents were likely not necessary after routine ureteroscopy, there appeared to be no consensus in practice patterns. This may have been secondary to a lack of subanalysis regarding stenting for distal ureteral calculi, which the lit-erature has increasingly suggested non-stenting may bene fi t. Although both community and aca-demic urologists were surveyed, it would have

S. A. Cohen , M.D. Urology Division, Surgery Department , U.C. San Diego Health System , San Diego , CA , USA

R. L. Sur , M.D. (*) Division of Urology, Surgery Department , U.C. San Diego Health System , 200 W Arbor Dr. #8897 , San Diego , CA 92103-8897 , USA e-mail: [email protected]

29 Ureteral Stenting or No Stenting

Seth A. Cohen and Roger L. Sur

342 S.A. Cohen and R.L. Sur

been interesting to note if resident availability in fl uenced academic physicians to embrace non-stenting more frequently. Future research exam-ining an urologist’s rationale for stenting would be useful as well—e.g., is it done to prevent read-mission, facilitate stone fragment passage, and/or prevent stricture development.

Potential Advantages of Placing a Stent

When considering the reasons for placing a ure-teral stent subsequent to ureteroscopy, the litera-ture provides physiologic rationale for placing a stent. Reactive ureteral edema after ureteroscopy and stone manipulation may lead to obstruction, threatening renal function, and causing fl ank pain. A ureteral stent serves to decompress this system postoperatively. Moreover the rare but recognized risk of ureteral stricture is potentially prevented with ureteral stenting as it promotes ureteral healing [ 2 ] . In the setting of ureteral dila-tion, animal models have shown persistent ure-teral edema and upper urinary tract obstruction up to 96 h after dilation; a ureteral stent could potentially decompress this system postopera-tively [ 3, 4 ] . In addition, it has been postulated that a ureteral stent could aide in passage of residual stone fragments, secondary to passive dilation of the ureter [ 5– 7 ] .

There is also data supporting pre-stenting prior to ureteroscopy to facilitate ease of surgery. A ret-rospective analysis evaluated the cost-effective-ness of pre-stenting patients prior to ureteroscopy [ 8 ] . The retrospective review identi fi ed pre-stented and matched control of unstented subjects, with a 19.5 day (range 6–67) median duration of preoperative stent placement. Total healthcare cost for stone clearance in patients with stone bur-den >1 cm who had been pre-stented was signi fi cantly less than the median cost of those not stented, $17,706 and $27,806 p = 0.03, respec-tively. Decreased operative time and reoperative rates explained this fi nding. In those patients with stone burden <1 cm, pre-stenting actually

signi fi cantly increased the overall cost of stone removal, $12,344 versus $10,872 p = 0.006.

Potential Disadvantages of Placing a Stent

Indwelling stents have been documented to have signi fi cant patient morbidity, with up to 90% of patients with an indwelling ureteral stent com-plaining of urgency, frequency, fl ank pain during void, and hematuria [ 9 ] . Ureteral stents can frac-ture, migrate, knot, and encrust, making removal dif fi cult and hazardous for the patient [ 2 ] . A large study examining the natural history of 330 ureteral stents in 181 patients demonstrated 47% of the stents were encrusted, with an encrustation rate of 26% at less than 6 weeks, 56% at 6–12 weeks, and 75% at more than 12 weeks, while 14% stents necessitated surgery for removal [ 10 ] . The median dwell time for stents that resisted removal was 72 (range 14–124) days and 31 (range 30–60) days for irremovable stents. In rare circumstances retained stents have been found to obstruct the renal unit and to potentially lead to patient death. [ 11– 13 ] . Thus, the time course of encrustation is associated with increased dwelling time, but appears dif fi cult to predict. Although studies are underway to determine risk factors for encrusta-tion, including proteomic evaluations of stent bio fi lms, data does indicate that the shorter the interval of placement the lesser the discomfort for the patient [ 14, 15 ] .

The increased costs associated with ureteral stent placement after ureteroscopy have been documented in previous studies [ 16, 17 ] . The costs, however, are not only limited to the uret-eroscopy but also to the postoperative period when the stent is cystoscopically removed, given the common practice of performing outpatient cystoscopy to remove ureteral stents [ 1 ] . This additional cost of stent removal has been decried as a potential reason to avoid stenting if medi-cally feasible, and some groups have gone as far to devise creative ways to keep this cost down [ 18 ] .


Quality of Life

In addition to the inconvenience and discomfort of removing an indwelling ureteral stent, one must also consider the impact of an indwelling ureteral stent on patients’ health-related quality of life (HRQoL). HRQoL assessment uses mea-surement instruments, such as surveys, to evalu-ate aspects of health and well-being as valued by patients, focusing on physical, emotional, and cognitive function, in addition to their abilities to participate in meaningful activities within their workplace, families, and communities [ 19 ] . The signi fi cance of stent morbidity becomes more compelling when one considers that kidney stone patients have been reported to exhibit higher depression rates than normal population [ 20 ] .

When determining the appropriate treatment strategy for patients with stone disease, efforts to assess how ureteroscopy and stent placement impact HRQoL could potentially alter practice patterns and patient management. As mentioned, ureteral stents are associated with increased irri-tative voiding symptoms and hematuria. At this time, there is no stone-speci fi c instrument that has been validated for QoL assessment in neph-rolithiasis patients, thus there is no de fi nitive data regarding HRQoL and the use of ureteral stents in lithotripsy. However, informative inquiries have taken place. For instance, a study using the International Prostate Symptom Score (IPSS), International Continence Society (ICS) male and quality of life (QoL), and Bristol Female Lower Urinary Tract Symptoms (BFLUTS) question-naires to characterize voiding symptoms in 48 patients with indwelling ureteral stents before and after stent removal attempted to validate the morbidity of stents [ 21 ] . Not surprisingly mean total IPSS was signi fi cantly higher with the stent in situ, compared to after removal, though only the domain “feeling of incomplete emptying” had a statistically signi fi cant difference in value. Dysuria and hematuria were additional domains added to the questionnaire and these domains demonstrated signi fi cant improvement with stent removal. The ICS and BFLUTS questionnaires found patients to have a higher prevalence of

storage symptoms (up to 70%) associated with a high degree of bother and signi fi cant dissatisfac-tion with QoL, with the stent in situ. This data would support the notion that patients suffer decreased QoL with stents in place, yielding another reason to perform stentless ureteroscopy, if safe and feasible.

Objective Data Regarding Stent Placement

Multiple randomized control trials (RCTs) have been performed within the last 10 years examining surgical outcomes in stented versus non-stented patients undergoing ureteroscopy. A multi-center prospective randomized controlled trial was per-formed in 2001, assessing pain, stone-free rates, and complications in patients undergoing uret-eroscopic treatment of distal ureteral calculi (de fi ned as below the iliac vessels on radiographic imaging) in subjects with or without ureteral stents (53 in stented group and 54 in unstented group) [ 22 ] . Despite 57% of unstented patients having undergone ureteral balloon or tapered dilation, there was no difference in readmission rate for fl ank pain (unstented 4 (7.4%) vs. stented 0, p > 0.05). Furthermore, stented subjects had more postoperative fl ank pain ( p = 0.005), blad-der pain ( p < 0.001), urinary symptoms ( p = 0.002), overall pain ( p < 0.001), and total narcotic use ( p < 0.001) compared to the unstented group. Long-term outcomes did not appear to be affected by lack of stenting as the stone-free rate was sim-ilar at 99.1%, and all patients who underwent imaging postoperatively were without evidence of ureteral stricture. The authors concluded uncomplicated ureteroscopy (including lack of signi fi cant ureteral trauma or ureteral perfora-tion) for the treatment of distal ureteral calculi, with or without intraoperative distal ureteral dila-tion, can be safely performed without placement of a ureteral stent.

A 2002 randomized controlled trial evaluated 60 patients, 30 stented, and 30 non-stented, after uncomplicated ureteroscopic lithotripsy with an electrohydraulic lithotripter [ 23 ] . Patients with-out ureteral stents were found to have similar


stone-free rates, renal function recovery, pain reduction, and less irritative voiding symptoms as compared to those patients in which stents were placed. After discharge, 1 (3.3%) patient in the non-stented group returned with intolerable fl ank pain, as opposed to 0 in the stented group. Overall, the authors found it was not necessary to place a ureteral stent routinely after uncomplicated uret-eroscopic electrohydraulic lithotripsy, without ureteral dilation, for stones smaller than 1 cm.

In 2004, a randomized controlled trial evalu-ated 104 patients, 52 stented versus 52 non-stented after uncomplicated ureteroscopic stone removal, without dilation, using pneumatic intra-corporeal lithotripsy [ 24 ] . No differences were seen in dysuria, hematuria, and frequency/urgency or stricture rates, though the stented group experienced higher pain scores on postop-erative day 3. There was no difference in anatom-ical ureteral narrowing on IVP at 6 months follow-up between the two groups. The authors concluded that when using pneumatic intracorpo-real lithotripsy, routine stent placement remained advisable. Of note, this is the only randomized controlled trial to date, in which there was a signi fi cantly higher rate of hospital readmission in the non-stented population.

A 2008 study enrolled 43 patients with distal (below the inferior part of the sacroiliac joint) stones larger than 1 cm in a randomized con-trolled trial comparing stent (21 cases) versus no stent (22 cases) after ureteroscopy with pneu-matic lithotripsy [ 25 ] . No patients required dila-tion of the ureteral ori fi ce or intramural ureter. Mean stone size was comparable between the groups (13.28 vs. 12.90 mm). There was no sta-tistically signi fi cant difference between the groups for postoperative pain and hematuria, though voiding irritative symptoms were much higher in the stented group. The authors were diligent in removing residual fragments ³ 4 mm with additional forceps application. This extra attention given to ensure removal of all residual fragments ³ 4 mm may have contributed to the lack of difference in return hospital visits between the stented (1 (4.7%)) and non-stented patients (1 (4.5%)), as opposed to those results found in the previously discussed 2004 study using pneumatic

lithotripsy. This highlights the importance of removing large, ³ 4 mm fragments, particularly in an unstented patient. Of note, a study in 1998 compared various lithotrites and found fragments ³ 4 mm are produced by all types of endoscopic lithotrites, except for the holmium:YAG laser [ 26 ] . Thus, when using electrohydraulic or pneu-matic lithotrites, it appears to behoove practitio-ners to diligently remove, when possible, residual fragments ³ 4 mm.

A 2008 randomized controlled trial attempted to overcome the limitations of previous trials, which had included small sample size, patient heterogeneity, improper de fi nition of “uncompli-cated ureteroscopy,” poor documentation of out-comes, and lack of long-term follow-up—all of which compromised the external validity of the results [ 27 ] . The de fi nition of “uncomplicated ureteroscopy,” was explicitly described as uret-eroscopy in adults 18 years or older with stones located in the distal part of the ureter below the iliac vessels, with largest stone diameter of less than 1.5 cm, “no multiple complex stones” no distal ureteral pathology; no intraoperative major complications (e.g., ureteral perforation), and complete stone disintegration or removal. The study was large including 110 stented and 110 unstented subjects. Both patients and surgeons were blinded to group allocation, with the sur-geon informed of group allocation when the ure-teroscopic portion was completed. All stented patients had ureteral stents in place for 2 weeks. There was no difference in readmission, low-grade fever, fl ank pain, hematuria, urinary tract infection, time to return to normal physical activ-ity, or postoperative stricture. Dysuria was signi fi cantly less in the non-stented group.

Synthesizing the Data: Meta-Analyses

In 2007, Nabi et al. published a meta-analysis of nine randomized controlled trials examining the outcomes with and without stenting after uret-eroscopy [ 28 ] . The authors found a signi fi cantly higher incidence of dysuria (relative risk 2.25, 95% con fi dence interval (CI) 1.14–4.43) and fre-quency or urgency (2.00, 95% CI 1.11–3.62).


There was no signi fi cant difference in postoperative requirement for analgesia, urinary tract infec-tions, stone-free rate, and postoperative strictures. The authors noted that marked heterogeneity pre-vented pooling of data for outcomes such as fl ank pain. Pooled analysis suggested a nonsigni fi cant trend toward a reduced likelihood of unplanned medical visits and hospital admissions in the stented group (RR = 0.53, 95% CI 0.17–1.60). They concluded that stenting in uncomplicated ureteroscopy leads to considerable morbidity, but there is still signi fi cant uncertainty with the role of stenting due to “lack of standardization of outcome measures, marked clinical heterogene-ity, withdrawal after randomization, imprecision in measurement of outcomes (large con fi dence intervals), and poor reporting of published clini-cal trials.”

In 2008, a systematic review of the same nine randomized controlled trials, reported similar fi ndings to the previous meta-analysis study with respect to stent morbidity and lack of long-term advantages. However, the systematic review con-cluded stenting in an uncomplicated patient is not mandatory, a slightly different interpretation [ 29 ] . The difference in the interpretation of the data may lie in the methodological differences between a systematic review and a meta-analysis, whereas the latter incorporates complex statistical meth-ods of combining evidence.

A combined systematic review and meta-anal-ysis performed in 2011 is one of the most con-temporary reports involving 16 randomized controlled trials [ 30 ] . No signi fi cant differences were found between the groups in fever, urinary tract infection, need for analgesia, unplanned readmission, and late postoperative complica-tions. It is interesting that the authors concluded that routine stenting is not necessary despite the admitted “bias and different quality levels of the included trials” in this meta-analysis. In contra-distinction, another recent 2011 meta-analysis of 14 randomized controlled trials demonstrated signi fi cant bene fi t to non-stenting but admitted that the poor quality of available studies resulted in uncertainty in the role of stenting [ 31 ] . The authors noted data from the 14 randomized con-trolled trials were of moderate to poor quality,

had clinical heterogeneity (varying sizes of ureteroscopes, different intracorporeal lithotripsy devices, variations in practice), lacked standard-ized de fi nition of “uncomplicated ureteroscopy,” had imprecision in outcomes (large con fi dence intervals)—all reasons underscoring the need for further investigation.

What Shall We De fi ne as Complex Ureteroscopy?

The results of the aforementioned RCT’s and meta-analyses all reserve conclusions for “uncomplicated” ureteroscopy. These conclu-sions therefore beget the corollary question—what de fi nes “complicated” or “complex” ureteroscopy? The characteristics that de fi ne complex ureteroscopy will most likely provide clinical guidelines to elucidate optimal candi-dates for stentless patients. The current literature unfortunately inconsistently or even fails to de fi ne complicated criteria. It is intuitively a mul-tifaceted issue involving patient and stone char-acteristics, surgical technique as well as surgical equipment variables.

A retrospective evaluation of 219 unstented patients of whom 39 developed postoperative ureteroscopic complications was performed with the goal of determining factors that predict post-operative complications. Of the 39 complications 26 included postoperative obstruction and these were analyzed. The authors concluded that bilat-eral stentless surgery, history of recent of recur-rent urinary tract infections, history of recurrent urolithiasis are the greatest risk factors for post-operative complications. They postulated that a history of urolithiasis and/or urinary tract infec-tions induces abnormal ureteral mechanics, which subsequently predispose these patients to postop-erative problems. Prolonged surgical time >45 min with concomitant use of lithotripsy as well as renal pelvic stones were additional risk factors associated with complications [ 32 ] .

A 2011 retrospective review was performed on patients who had undergone “uncomplicated ureteroscopy” with pneumatic lithotripsy and subsequently required emergent stenting, with the


goal of identifying factors to more completely stratify the subset of ureteroscopy patients who require stents [ 33 ] . In over 3 years, 276 uncom-plicated ureteroscopy procedures were per-formed; in which 23 (8.3%) patients require emergent ureteral stenting in the initial 24 h sec-ondary to intractable colic pain. All patients had undergone ureteroscopy for what was believed to be a single ureteral calculus through a semirigid ureteroscope. No patient underwent ureteral dila-tion. Stones were extracted with basket or for-ceps, with or without pneumatic intracorporeal lithotripsy. Patients were excluded from the review if they had stents placed preoperatively, multiple stones, evidence of active infection, a solitary kidney, or suspected additional ureteral pathologic features (e.g., ureteral stricture). Stones were located in the distal ureter in 11 patients (47.8%), mid-ureter in 6 (26.1%), and proximal ureter in 6 (26.1%). The authors reviewed operative recordings and radiographs and determined that longer operative time, repeated access, large stones, impacted calculi with ureteral wall edema, a mildly narrowed ure-teral segment, untreated caliceal small calculi, and a recent history of urinary tract infection were risk factors for postoperative intervention.

Those Situations That Require Further Investigation

In the setting of balloon dilation of the distal ure-ter, there is no current consensus on whether stenting is necessary. Animal models have found persistent ureteral edema and upper urinary tract obstruction up to 96 h after dilation [ 3, 4 ] . However, to our knowledge, limited human data available suggests that stenting after balloon dila-tion is necessary. The meta-analysis by Nabi et al. demonstrates the inconsistent use of ureteral dila-tion in the available literature (two studies required dilation, one study excluded subjects who were dilated, three studies did not require dilation) and therefore the unclear need to stent after ureteral dilation [ 28 ] . The limited data from the RCT’s suggests no untoward effect of dilat-ing, but again the data is too heterogeneous to

permit conclusive recommendations. We never-theless acknowledge the growing body of litera-ture that does support a possible stentless approach to ureteral dilation. A subset analysis by Hollenbeck et al. of their cohorts of stented versus non-stented patients who had undergone ureteral dilation found no difference in the risk of postoperative complications [ 34 ] . In 2011, a multi-center prospective randomized control trial enrolled 505 patients undergoing ureteroscopy, with 286 requiring balloon dilation of the ureteral ori fi ce, of which 144 were randomized to be stented and 142 were randomized to receive no stent [ 35 ] . In each case of dilation, a 18 Fr-4 cm balloon dilator was applied for approximately 2–3 min. At 1 week postoperatively, patients’ pain, dysuria, and urgency were evaluated, in addition to urine culture, plain X-ray, and ultra-sounds obtained. At 6 months, follow-up intrave-nous urogram was obtained to evaluate ureteral narrowing. Although there was no signi fi cant dif-ference in pain, infectious complications, unplanned visits, or ureteral narrowing, the irrita-tive symptoms (dysuria and urgency) and hema-turia, were more common in the stented group.

Pregnant patients undergoing ureteroscopic management of urolithiasis represent another population for which there is no consensus on postoperative stenting. In 2006, a retrospective review of seven patients found routine insertion of ureteral stents with pullout strings for at least 72 h reduces pain and analgesic use postopera-tively [ 36 ] . In 2009, Rana et al. reported on a series of 19 pregnant patients who underwent ureteroscopy, 12 (63%) of which were left with postoperative ureteral stents; 2 (11%) developed retained, encrusted stents requiring cystolithola-pexy and ureteroscopy for removal [ 37 ] . In 2011, Isen et al. published a descriptive analysis of the management of 36 pregnant women with symp-tomatic ureteric stones [ 38 ] . Nine (25%) were managed with ureteroscopic lithotripsy, in which a ureteral catheter was placed at the end of the procedure and withdrawn on the fi rst postopera-tive day. No signi fi cant complications were reported. Thus, the management of stone disease in pregnant patients requires thought and it should be reiterated that indwelling devices, including


stents, are associated with increased risks of infection, pain, bacteriuria, dislodgement, and migration—these events during pregnancy may place pregnancy itself at risk [ 39 ] . Further studies are needed to elucidate the role of postoperative stent placement in the pregnant population.

Previous literature had reported that patients at highest risk for stricture after ureteroscopy were those with impacted calculi, up to an inci-dence of 24% in patients with stone impaction greater than 2 months in duration, with the pri-mary risk factor being ureteral perforation at the stone site [ 40, 41 ] . Cevik et al. prospectively ran-domized 60 patients with impacted ureteral stones to undergo ureteroscopic lithotripsy with and without ureteral stent placement [ 42 ] . Impacted ureteral stones were de fi ned as stones that did not allow passage of a guidewire at initial attempts before the disintegration of stones at ureteros-copy. Of note, ureteroscopic pneumatic litho-tripsy was utilized for distal and middle ureteral impacted calculi, with an 8 French semirigid ure-teroscope, without ureteral dilation. Excretory urography was performed 3 months after the pro-cedure. Until postoperative (POD) day 5, narcotic use was more frequently necessary in the non-stent group ( p = 0.004); after POD 5, narcotics were almost unnecessary in the no-stent patients. Stent related irritative symptoms were signi fi cantly higher in the stented group (93 vs. 10%, p < 0.001). Rates of postoperative compli-cations in the stented and no-stent group were otherwise similar: fever (10 vs. 6%, p = 1), pain delaying discharge (10 vs. 23%, p = 0.299), emer-gency department visits (10 vs. 20%, p = 0.472), and stricture rate (0% in both groups). The authors concluded that routine ureteral stent placement after ureteroscopic lithotripsy for impacted ure-teral stones was not necessary in patients without complications.

Conclusions

A multitude of recent evidence in the literature suggest routine stent placement after uncompli-cated ureteroscopy may not be necessary, espe-cially for small distal ureteral calculi; however, the

current level of evidence leaves some uncertainty to this universal recommendation. Though it is incontrovertible that stents are a source of excess morbidity and that not all patients should be stented, de fi ning those exact patients who are ideal for stentless surgery still requires investiga-tion. Exclusion criteria for the non-stenting rec-ommendation include solitary kidney, renal insuf fi ciency, recent history of urinary tract infec-tion, bilateral ureteroscopy, intraoperative ureteral injury, prolonged surgery, pregnancy, and poor access to postoperative on-call urologic care.

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Ureteroscopy || Ureteral Stenting or No Stenting