Complications following ureteroscopy

Clinical factors associated with postoperative hydronephrosis after ureteroscopic lithotripsy

Purpose

This study aimed to determine the predictors of ipsilateral hydronephrosis after ureteroscopic lithotripsy for ureteral calculi.

Materials and Methods

From January 2010 to December 2014, a total of 204 patients with ureteral calculi who underwent ureteroscopic lithotripsy were reviewed. Patients with lack of clinical data, presence of ureteral rupture, and who underwent simultaneous percutaneous nephrolithotomy (PNL) were excluded. Postoperative hydronephrosis was determined via computed tomographic scan or renal ultrasonography, at 6 months after ureteroscopic lithotripsy. Multivariable analysis was performed to determine clinical factors associated with ipsilateral hydronephrosis.

Results

A total of 137 patients were enrolled in this study. The mean age of the patients was 58.8±14.2 years and the mean stone size was 10.0±4.6 mm. The stone-free rate was 85.4%. Overall, 44 of the 137 patients (32.1%) had postoperative hydronephrosis. Significant differences between the hydronephrosis and nonhydronephrosis groups were noted in terms of stone location, preoperative hydronephrosis, impacted stone, operation time, and ureteral stent duration (all, p<0.05). On multivariable analysis, increasing preoperative diameter of the hydronephrotic kidney (adjusted odds ratio [OR], 1.21; 95% confidence interval [CI], 1.12–1.31; p=0.001) and impacted stone (adjusted OR, 3.01; 95% CI, 1.15–7.61; p=0.031) independently predicted the occurrence of postoperative hydronpehrosis.

Conclusions

Large preoperative diameter of the hydronephrotic kidney and presence of impacted stones were associated with hydronephrosis after ureteroscopic stone removal. Therefore, patients with these predictive factors undergo more intensive imaging follow-up in order to prevent renal deterioration due to postoperative hydronephrosis.

Ureterorenoscopy: avoiding and managing the complications

Retrograde exploration of the ureter and kidneys is currently a widely used and well-established procedure to deal with problems of a diagnostic and therapeutic nature with reduced invasiveness. The process of miniaturizing the instruments combined with the steady improvement in video quality has continuously amplified its potential applications, maintaining the procedure safe and rapid. During an operation, however, unexpected events may condition a change to the programme or determine the onset of even more serious complications. Our aim is to analyze such events and complications and recommend potential solutions to prevent and/or deal with such happenings.

Complications of ureteroscopy

Ureteroscopy has undergone a dramatic evolution over the last two decades. Although ureteroscopic injury is the most common cause of ureteral trauma because of the large number of ureteroscopic procedures performed, improvements in instrumentation and technique have resulted in a reduced incidence of serious complications. Despite significant technologic advances, however, surgical misadventures still occur, some of which have lasting consequences. Careful attention to instrument selection and surgical technique are critical to reduce untoward events related to ureteroscopy. As such, adverse sequelae associated with ureteroscopy should be related to the underlying pathology itself rather than to the treatment.

Techniques of ureteroscopy

The flexible ureteroscope has revolutionized the diagnosis and treatment of the entire upper urinary tract. Endoscopic tools have evolved, providing the surgeon with the armamentarium necessary to treat many different pathologic processes. Almost all renal calculi can be treated with retrograde ureteroscopy. The fragility of these new endoscopes is a concern, and great care must be taken when using them. With good technique and proper use of instruments, their working life can be extended.

Assessment of stricture formation with the ureteral access sheath

OBJECTIVES

To analyze the long-term incidence of ureteral stricture formation in a series of patients in whom a new-generation ureteral access sheath was used. A new generation of ureteral access sheaths has been developed to facilitate ureteroscopic procedures. However, some have questioned their safety and whether the device might cause significant ureteral trauma.

METHODS

Between September 1999 and July 2001, 150 consecutive ureteroscopic procedures with adjunctive use of an access sheath were performed. A retrospective chart review to April 2002 was done. Of the 150 patients, 130 underwent ureteroscopy for ureteral stones. Patients who underwent endoureterotomy or treatment of transitional cell carcinoma were excluded from this analysis. Sixty-two patients had follow-up greater than 3 months and were included in the analysis. Overall, 71 ureteroscopic procedures were performed, with 9 patients undergoing multiple procedures. Ninety-two percent of the patients had pathologic findings above the iliac vessels. The average patient age was 45.3 years (range 17 to 76), and 70% and 30% of the patients were male and female, respectively. The mean clinical follow-up was 332 days (range 95 to 821), and follow-up imaging was performed within 3 months after ureteroscopy in all patients.

RESULTS

The 10/12F access sheath was used in 8 ureteroscopic procedures (11.2%), the 12/14F access sheath in 56 (78.9%), and the 14/16F access sheath in 7 (9.8%). One stricture was identified on follow-up imaging of 71 procedures performed, for an incidence of 1.4%. The patient developed the stricture at the ureteropelvic junction after multiple ureteroscopic procedures to manage recurrent struvite calculi. The access sheath did not appear to be a contributing factor.

CONCLUSIONS

The results of our series indicate that the ureteral access sheath is safe and beneficial for routine use to facilitate flexible ureteroscopy. However, awareness of the potential ischemic effects with the use of unnecessarily large sheaths for long periods in patients at risk of ischemic injury should be considered. We advocate the routine use of the device for most flexible ureteroscopic procedures proximal to the iliac vessels.

Laser Doppler flowmetric determination of ureteral blood flow after ureteral access sheath placement

BACKGROUND AND PURPOSE

The ureteral access sheath has positively impacted ureteroscopy by decreasing operative times and increasing success rates. However, as previous studies have suggested that large-caliber endoscopes may cause ureteral ischemia, concern has been raised about the impact of access sheath insertion on ureteral blood flow. We sought to determine whether the access sheath compromises ureteral blood supply and, if so, causes ischemic damage to the ureter during ureteroscopic procedures.

MATERIALS AND METHODS

Using a swine animal model, ureteral blood flow was measured with a laser Doppler flowmeter. Eleven ureteral units were randomized into four study groups: those dilated with 10F-12F, 12F-14F, and 14F-16F access sheaths (N = 3 per group) and an undilated control group (N = 2). Blood flow measurements were obtained from the proximal ureter via laser Doppler flowmetry for 70 minutes at 5-minute intervals. Hemodynamic variability was controlled for through intraoperative heart rate and oxygen saturation monitoring, as well as a second Doppler probe that was placed on the animal's skin, from which readings were also taken every 5 minutes. Results were correlated with histopathologic findings.

RESULTS

The control group demonstrated little ureteral blood flow variability over the course of 70 minutes. The study groups that were dilated with sheaths, however, all showed a decrease in ureteral blood flow after access sheath insertion, with the flow in animals dilated with 12F-14F and 14F-16F sheaths dropping below 50% of baseline. This initial drop in blood flow was followed by a gradual increase from nadir toward baseline values over the course of the study. On average, the 14F-16F group reached nadir more quickly and took longer to restore its ureteral blood flow. All animals remained hemodynamically stable throughout the study, showing only minimal variability in heart rate, oxygen saturation, and skin blood flow over the 70-minute experiment. Histologically, there was no evidence of ischemic damage in any of the study groups at 72 hours.

CONCLUSIONS

In this animal model, the access sheath does cause a transient decrease in ureteral blood flow. Nonetheless, compensatory mechanisms of the ureteral wall restore blood flow to near-baseline rates and preserve urothelial integrity, suggesting that use of the ureteral access sheath remains a safe adjunct to flexible ureteroscopy. Because the chronic effects of the access sheath have yet to be elucidated, care must be taken in selecting an appropriate-size sheath for each individual case. Preventive measures may be available to help avoid sheath-related ureteral injury in those patients identified as high risk.

Follow-up functional radiographic studies are not mandatory for all patients after ureteroscopy

OBJECTIVES

To evaluate the usefulness of follow-up radiographic studies after ureteroscopy by retrospective chart review.

METHODS

We reviewed the charts of 118 patients who underwent 134 ureteroscopic procedures from January 1998 to November 1999.

RESULTS

Follow-up was obtained at our institution for 87 patients. The follow-up period ranged from 3 to 34 weeks (mean 7, SE +/- 0.75). Of 10 patients who underwent ureteroscopy for diagnostic purposes, none had postoperative pain or obstruction on follow-up radiographic studies. Of 77 patients who underwent ureteroscopy for calculi, 12 (16%) had postoperative obstruction. One third of patients with residual obstruction (4 of 12) complained of persistent pain versus 6% of patients without evidence of obstruction (4 of 65) (P = 0.02). Twelve patients had residual stone fragments on their follow-up radiographic studies; 5 (42%) of these patients complained of pain versus 3 (5%) of 65 patients who were stone free after surgery (P = 0.002). The use of pain to predict either obstruction or residual fragments had a negative and positive predictive value of 83% and 75%, respectively. Preoperative obstruction and postoperative pain were combined as one indicator for the presence of residual fragments and postoperative obstruction. Patients who had preoperative obstruction and presented with postoperative pain had a 67% chance of having residual fragments and a 50% chance of residual obstruction, and 96% of patients without preoperative obstruction and no postoperative pain had no persistent obstruction or residual fragments (P = 0.001).

CONCLUSIONS

For patients who present for ureteroscopy with no obstruction and report no pain at follow-up, a plain radiograph may be sufficient. For patients who present with obstruction and report pain during follow-up, functional imaging studies are recommended.

A stone developed within the dilated intravesical ureter following ureteroscopy

A 58-year-old man presented with a stone within the dilated intravesical ureter, which was probably attributable to a previous ureteroscopy. Transurethral incision of the right intravesical ureter and lithotripsy were carried out without subsequent urinary tract impairment. Although some complications resulting from ureteroscopy, such as ureteral stricture, ureteral perforation and vesicoureteral reflux, have been reported, this complication is considered to be very rare.

Ureteroscopy: current practice and long-term complications

PURPOSE

We compared a current cohort of patients who underwent ureteroscopy to a cohort from the early 1980s to determine changes in success, indications and long-term complications of the procedure.

MATERIALS AND METHODS

A chart review was performed of 194 patients who underwent 209 ureteroscopic procedures at our institution during 1992. This group was then statistically compared to 317 patients who underwent 346 ureteroscopies between 1982 and 1985.

RESULTS

The current indications for ureteroscopy were calculus extraction (67% of the cases), diagnosis (28%) and stent manipulation (5%). These indications differed from those of the early series, in which 84% of all ureteroscopies were performed for calculus extraction and 16% for diagnosis. Overall ureteroscopic success rate increased from 86 to 96% (p < 0.001). Success of stone extraction improved from 89 to 95% (p = 0.08, distal success rate 95 to 97% and proximal success rate 72 to 77%). Success of diagnostic inspections increased from 73 to 98% (p < 0.001). In the early series failure was usually due to inability to traverse the ureter (54% of the cases), while currently failure is due almost exclusively to impassable ureteral strictures (63%). The overall complication rate decreased from 20 to 12% (p = 0.01) and the rate of significant complications decreased from 6.6 to 1.5% (p < 0.05). Clinical followup (mean 36 months) for all patients and radiological followup (mean 9.8 months) for 67% of eligible patients detected only 1 ureteral stricture. The remaining patients were asymptomatic after the ureteroscopic procedure.

CONCLUSIONS

Improvements in ureteroscope design, accessories and technique have led to a significant increase in the success of diagnostic and therapeutic ureteroscopy while decreasing morbidity. Outpatient ureteroscopic stone extraction, particularly for distal ureteral calculi, is almost uniformly successful with low morbidity. The long-term complication rate of ureteroscopy is 0.5%.

Stone granuloma: a cause of ureteral stricture

Ureteral stricture is a recognized complication of ureteroscopy and ureteral stone fragmentation. Although most strictures are either asymptomatic or easily dilated, there are some strictures that result in progressive ureteral obstruction, do not respond to ureteral dilation and require operative intervention. A review of 125 percutaneous nephrostolithotomies for staghorn stone disease and 652 ureteroscopic stone fragmentations revealed 5 cases in which refractory ureteral strictures developed, requiring operative intervention. In 4 patients a "stone granuloma," embedded particles of calcium oxalate associated with macrophages and foreign body giant cells, was found with surrounding fibrosis and ureteral obstruction. In the remaining patient a suture granuloma from a recent ureterolithotomy was the source of the stricture. In each instance of stone granuloma the particles of calcium oxalate had become embedded in the wall as a consequence of ureteroscopic stone fragmentation and partial ureteral wall disruption. During ureteroscopy and intracorporeal lithotripsy every effort should be made to prevent calcium oxalate particles from becoming embedded in the ureteral wall. They are not inert and may cause irreversible stricture formation. To our knowledge, stone granuloma is a previously undescribed phenomenon and should be suspected when ureteral strictures that occur following ureteroscopy do not respond to endourological methods of management.

Ultrathin flexible endoscopes for ureteroscopy. A preliminary experimental and clinical study

Recent advances in fiberoptic technology have resulted in the development of endoscopes with an outer diameter of less than 6 F, including an irrigating or working channel. After preliminary testing of these ultrathin fiberscopes for ureteroscopy on 6 pigs, 17 patients were examined during routine retrograde pyelography. Prototypes of flexible endoscopes without an actively deflectable tip and an outer diameter of 5.5 F (= 1.8 mm) and a 1.5 F (= 0.5 mm) channel were used. Fine-needle aspiration cytology was obtained through the channel. The feasibility, performance and benefits of ureteroscopy with ultrathin, flexible endoscopes were evaluated. At present the lack of maneuverability and the fragility of the fiberscopes limit this method. Yet its routine clinical use, in addition to retrograde ureteropyelography under local anesthesia, shows great promise.

Long-term results of transurethral lithotripsy with the rigid ureteroscope: injury of intramural ureter

We treated 208 patients with ureteral calculi via transurethral lithotripsy using the rigid ureteroscope between March 1985 and April 1988. A total of 220 ureteroscopic procedures was performed in 217 ureters. Complete removal was achieved after 180 procedures (81.8%) and incomplete removal was achieved after 9 (4.1%). In 31 cases (14.1%) the stone could not be removed because of various reasons. Ureteral disruption was observed in 1 case (0.5%), which was treated successfully with reconstruction. Ureteral perforation occurred in 15 cases (6.8%) and was treated successfully except for 1 patient (0.5%) in whom ureteral stricture was observed requiring reconstruction. From long-term followup of sequential excretory urography and voiding cystography, mild stricture at the vesical end of the ureter was noted in 3 of 86 ureters (3.5%) and vesicoureteral reflux was noted in 7 of 73 (9.6%). These results indicate that the injury to the intramural ureter might arise from the passage of the ureteroscope resulting in stricture and vesicoureteral reflux.

Treatment of distal ureteral stones in the horse riding position

From August 1986 through March 1987, 102 patients with 110 distal ureteral stones were treated in 110 sessions with the standard Dornier HM-3 lithotriptor in the so-called horse riding position. The majority of the patients (70 of 110, 63.7%) were treated for distal stones alone, whereas in a third (40 of 110, or 36.3%) treatment was performed for distal and upper stone localization during the same session. Additional treatment besides extracorporeal shock wave lithotripsy was necessary in 12.7% of the patients. Of the 110 patients 89.4% were without residual stones after a mean of 17.3 days. This modified position of the patient, which is specific to the Dornier HM-3 lithotriptor, makes possible treatment of distal ureteral stones with results comparable to those of endoscopic management but with less major complications (4.7%). A total of 7 patients had anal blood loss in the early postoperative period. Rectal bleeding ceased within 36 hours after treatment. The position also allows for treatment of stones at other, more proximal locations without great modifications to the position during the same session.

Pressure-controlled hydraulic dilation of the ureter: "one-step" ureteroscopy

A controlled pressure pump was used to dilate the ureteral orifice hydraulically with irrigant flow through the ureteroscope in 50 ureters in 48 patients. The method was successful in all but 1 patient, who had a dense, fibrotic intramural segment that required extensive ureteral meatotomy before the instrument could be inserted. All subsequent procedures (stone removal, relief of obstruction or diagnostic evaluation) were successful, and there were no cases of sepsis or signs of excessive intraureteral or intrapelvic pressure. Hydraulic dilation drastically reduced the time required for ureteroscopy and probably reduced the frequency of complications. Details of the technique and the precautions are provided.

Changing surgical aspects of urinary stone disease

Surgical management of urinary calculous disease has changed dramatically in the past decade. The development of percutaneous nephrostomy techniques has allowed new access to upper tract stones. Percutaneous removal of large calculi was made possible by the development of ultrasonic and electrohydraulic lithotripsy. All upper tract calculi can now be removed in 70 to 100 per cent of cases with minimal complications. Nephrostolithotomy has reduced transfusion rates and hospitalization costs and has markedly shortened convalescence periods compared with open surgery. Ureteroscopy followed nephrostolithotomy as advanced fiberoptic technology allowed the development of the small-caliber instruments required for this procedure. With experience, successful stone retrieval has occurred in 90 per cent or more of cases, again with minimal complications. As nephrostolithotomy and ureteroscopy have become available, the subspecialty of endourology has emerged and significantly changed the management of urinary tract calculi. Perhaps the most significant advance in stone therapy has been the design and implementation of extracorporeal shock wave lithotripsy. With this noninvasive technique, most renal and proximal ureteral calculi can be effectively treated with minimal morbidity and convalescence. Research in lithotripter design is continuing, with more advanced and effective machines on the horizon. The applicability of extracorporeal therapy for the treatment of biliary tract calculi is currently under investigation. Finally, one should not disparage medical therapy for recurrent nephrolithiasis. A comprehensive metabolic evaluation combined with selective medical therapy provides almost complete relief from recurrent stone formation and makes medical therapy an integral component of treating the patient with renal or ureteral calculi.

The transvesical approach for the removal of distal ureteral calculi

Our experience with a modification of transvesical ureterolithotomy in 12 patients in whom endourological extraction failed is presented and the technique is described. Successful removal of stones was achieved in all patients with 1 significant postoperative complication of a perivesical hematoma, which was drained percutaneously. Excretory urography and voiding cystourethrography at 3 months and 1 year postoperatively demonstrated no ureteral stricture or vesicoureteral reflux. When removal of distal ureteral stones by endourological means or extracorporeal shock wave lithotripsy fails, we recommend transvesical ureterolithotomy as an easy and rapid approach that necessitates minimal dissection away from blood vessels and avoids manipulation or displacement of the ureteral orifice.

A case of pediatric ureteroscopic lasertripsy

The standard treatment for ureteral calculi in children has been open surgical removal. Recently, we removed successfully a lower ureteral calculus in a young child with ureteroscopy and the pulsed dye laser. The improvements in smaller rigid and flexible ureteroscopes, in conjunction with lasertripsy, will expand its applications in the treatment of pediatric urolithiasis.

Ureteroscopic results and complications: experience with 130 cases

Since its introduction for general use, the role of rigid ureteroscopy in the diagnosis and therapy of urological disease has been in evolution. We evaluated retrospectively the experience at our institution with rigid ureteroscopy from January 1983 to July 1986 in an attempt to identify clinical situations or techniques that tended to increase the incidence of either success or complications. We determined that ureteroscopic complications were rare in procedures performed for diagnosis compared to those performed for calculi (2 of 33 or 6 per cent versus 27 of 99 or 27 per cent, p less than 0.025). The likelihood of failure or complication was greater for stones above than for those below the pelvic brim (15 of 25 or 60 per cent versus 26 of 75 or 35 per cent, p less than 0.05). Major complications were more common early in our experience (9 of 63 or 14 per cent versus 2 of 69 or 3 per cent for the combined years 1983 and 1984 compared to 1985 and 1986, p less than 0.05). Our success rates in the treatment of calculous disease were similar to those reported previously, and they were somewhat better for stones located below (62 of 75 or 83 per cent) than for those above (17 of 25 or 68 per cent) the pelvic brim. Based on our findings we conclude that carefully performed diagnostic ureteroscopy has little potential for major complications, ureteroscopy for stones above the pelvic brim should be avoided when possible, and an increased rate of complications and failures is expected early in any series owing at least partly to the learning curve effect.

Ureteroscopic stone manipulation in the upper third of ureter and the pelvicaliceal system

During the period of January 1984 to March 1987, a total of 15 patients with upper third ureteric calculi and 115 patients with renal calculi were treated by percutaneous nephrolithotomy (PCNL), transurethral ureteroscopy (TUU) or open surgery. In all patients, endoscopic techniques were the primary modalities of therapy. In 15 patients with upper third ureteric calculi and in 22 patients with 27 calculi in the pelvicaliceal system (five had bilateral calculi), TUU was carried out. The success rate was 67% for calculi in the upper third of ureter and 44% for calculi in the pelvicaliceal system. No persistent strictures or other serious complications were encountered. We conclude, that TUU, in experienced hands, could be considered for proximal ureteric calculi and for certain renal calculi, especially in poor risk patients and patients with only one kidney.

Management of ureteroscopic injuries

Ureteroscopy is an important technique in the management of calculous disease and ureteral lesions but it appears to have a greater potential for injury than percutaneous nephroscopy. In 2 years 4 patients with severe ureteroscopic injuries were treated. In 3 patients complete obstruction of the ureter occurred, and 1 had a major ureteral tear, prolonged urinary extravasation and infection. Even in the presence of total ureteral occlusion patients with short strictures were managed successfully percutaneously but the 2 patients with longer strictures were not. Previous surgery on the ureter or pelvic surgery and radiation therapy appear to be negative factors that affect adversely the ureteral blood supply, and potentiate poor healing and scarring. Nephrostomy tube drainage and ureteral stenting after ureteral dilation appear to be important steps in the percutaneous management of these patients.