Effect of stent duration on ureteral healing following endoureterotomy in an animal model

Duration of Ureteral Stenting Following Ureteroscopic Perforation in a Porcine Model

Objectives: Ureteroscopic ureteral perforations have been reported in up to 6% of cases, with recent studies suggesting a decline to less than 2%. Ureteroscopic perforations are managed with prolonged ureteral stenting of up to 6 weeks based on historical data. We sought to evaluate the time of urothelial healing and duration of ureteral stenting following a ureteroscopic perforation in a porcine model. Materials and Methods: Part A: Ureteral perforation using a semirigid ureteroscope was performed in 37 ureters. The ureters were stented using 4.7F × 22 cm stents for 3, 7, 10, or 14 days, and retrograde pyelograms performed after stent removal. Injured ureteral segments were collected for histologic evaluation. Part B: 8 ureters had endoscopic perforation and stenting for 7 days and then survived for 4 weeks for evaluation of urinary extravasation or hydronephrosis and histologic evaluation. Results: Part A: At 3 days of ureteral stenting, there was urinary extravasation on retrograde pyelograms and gross defect in all ureters; average creatinine increased (1.55-1.75 mg/dL). Starting at 7 days, no evidence of gross urothelial defects or extravasation, and average creatinine was stable. Histologic evaluation revealed urothelial healing by 7 days with ongoing tissue healing. Granulation tissue predominated in early phase of healing. Part B: With only 7 days of ureteral stenting, no extravasation or hydronephrosis developed a month after stent removal. Conclusions: Following ureteroscopic ureteral perforation in a porcine model, the urothelium is functionally intact with 7 days of stenting. These results are sustained without complications for at least 4 weeks after stent removal. While further studies are warranted, these results challenge the current practice of maintaining ureteral stenting for several weeks following ureteral perforation during ureteroscopy.

Laparoendoscopic management of midureteral strictures

The incidence of ureteral strictures has increased worldwide owing to the widespread use of laparoscopic and endourologic procedures. Midureteral strictures can be managed by either an endoscopic approach or surgical reconstruction, including open or minimally invasive (laparoscopic/robotic) techniques. Minimally invasive surgical ureteral reconstruction is gaining in popularity in the management of midureteral strictures. However, only a few studies have been published so far regarding the safety and efficacy of laparoscopic and robotic ureteral reconstruction procedures. Nevertheless, most of the studies have reported at least equivalent outcomes with the open approach. In general, strictures more than 2 cm, injury strictures, and strictures associated either with radiation or with reduced renal function of less than 25% may be managed more appropriately by minimally invasive surgical reconstruction, although the evidence to establish these recommendations is not yet adequate. Defects of 2 to 3 cm in length may be treated with laparoscopic or robot-assisted uretero-ureterostomy, whereas defects of 12 to 15 cm may be managed either via ureteral reimplantation with a Boari flap or via transuretero-ureterostomy in case of low bladder capacity. Cases with more extended defects can be reconstructed with the incorporation of the ileum in ureteral repair.

Concomitant endoureterotomy and dextranomer/hyaluronic acid subureteral injection for management of obstructive refluxing megaureter

PURPOSE

To present the results of our experience with combined endoureterotomy and endoscopic injection of dextranomer/hyaluronic acid (Deflux) for the treatment of primary obstructive refluxing megaureter (PORM).

PATIENTS AND METHODS

Eighteen children (12 female, 6 male; mean age-14 months) with 20 PORM units underwent concomitant endoureterotomy and endoscopic subureteral Deflux injection. All patients underwent endoureterotomy at the 6-o'clock position with insertion of a 3F Double-J ureteral stent into the obstructed segment of ureter and subureteral injection of Deflux at the 5-o'clock and 7-o'clock positions. The Double-J stent was left in place with its distal tip fixed with a single knot to the external genitalia for easy removal after 1 week. Patients with refluxing nonobstructive ureter on the contralateral side of the PORM unit (seven children) underwent simultaneous endoscopic subureteral injection of Deflux. Voiding cystourethrography (VCUG) was performed at 6 months, and ultrasonography was performed at 1 week 3, 6, and 12 months postoperatively.

RESULTS

With a mean follow-up of 30 months, the procedure was uneventful in all patients. Follow-up VCUG showed no evidence of reflux in 15 ureterorenal (75%), significant decrease in reflux grade in 2 (10%), and no change in 3 (15%) in the endoscopic treated PORM units. No evidence of reflux was observed in the treated contralateral refluxing nonobstructive ureters. Ultrasonography revealed no ureterovesical junction obstruction. In 19 ureterorenal (95%) units, there was a complete resolution or decrease in hydroureteronephrosis.

CONCLUSIONS

The results of this study demonstrate that combined endoureterotomy and subureteral injection of Deflux is safe and effective in the treatment of PORM in selected patients.

Antegrade percutaneous balloon dilation of ureteral strictures after failed pelviureteric or ureterovesical reimplantation in children

OBJECTIVES

To assess the morbidity and success rate of percutaneous treatment of the postoperative ureteric strictures in children.

MATERIALS AND METHODS

Between January 1994 and December 2003, 12 children were treated by antegrade percutaneous balloon dilation for postoperative ureteric strictures. Stenosis occurred at the pelviureteric junction in 5 cases and ureterovesical junction in 7 cases. The 10 boys and 2 girls were between 3 months and 14 years old (mean, 5 years ± 4.7 years). General anesthesia was used in 10 cases for nephrostomy catheter placement. Five ureteral stents were used additionally for nephrostomy drainage with a 6-F catheter. Both nephrostomy and ureteric stents were in place for 28.5 ± 12 days, then removed after control antegrade pyelography.

RESULTS

Dilation was technically successful in 9 of our patients. Two peroperative complications occurred. Postoperative results were evaluated by ultrasonography, intravenous urography, antegrade pyelography, and diethylene triamine pentaacetic acid renography that confirmed no obstacle in all 5 cases of pelviureteric stricture with a follow-up of 4 ± 2.9 years and in 4 cases of ureterovesical junction with a follow-up of 4.7 ± 2.8 years. Three unsuccessful results were reported: in 2 cases, the guide wire could not be advanced over the stenotic ureterovesical junction and in 1 case an early restenosis occurred that eventually required surgery.

CONCLUSIONS

Although the main treatment of the postoperative ureteral strictures is surgical, the percutaneous antegrade balloon dilation seems to be an alternative to surgery with a low morbidity rate and short hospitalization period.

Primary endoscopic management versus open revision of ureteroenteric anastomotic strictures after urinary diversion--single institution contemporary series

PURPOSE

To review our institutional experience in the management of ureteroenteric strictures by primary endoscopic intervention or primary open revision.

PATIENTS AND METHODS

Between January 2000 and December 2007, 28 patients with ureteroenteric strictures underwent endoscopic management (n = 21) or open revision (n = 7). Strictures were characterized with regard to length and side as well as time to failure between the two groups. Success was defined as symptomatic improvement and evidence of patency on follow-up radiologic imaging.

RESULTS

Of all study patients, 78.6% were symptomatic on presentation. Endoscopic intervention (balloon dilation, electroincision, or holmium endoureterotomy) was successful in six patients for an overall success rate of 27% with a median follow-up of 21 months. Open revision was successful in 87.5% (7 of 8) patients for whom initial endoscopic surgery had failed. The success rate of primary open revision was 71.4% (5 of 7 patients) with a mean follow-up of 18.1 months. For the entire series, left-sided strictures were more common than right sided strictures; however, side and stricture length were not found to be significant (P > 0.05) with regard to patency. Functional renal imaging studies were performed in 42.9% of all study patients postoperatively.

CONCLUSIONS

Endoscopic management continues to have success rates that remain lower than that of open revision. Left-sided strictures remain more common than right-sided strictures; however, side and stricture length were not found to be statistically significant in our series. The lack of consistent postoperative functional renal studies highlights the importance of diligent monitoring and warrants further study to develop a surveillance algorithm.

Endoscopic incision for obstruction of vesico-ureteric anastomosis in transplanted kidneys

OBJECTIVE

To report our experience of endoscopic incision for obstruction of vesico-ureteric anastomosis (VUA) in transplanted kidneys.

PATIENTS AND METHODS

Between February 2001 and March 2006, six men and two women (mean age 38 years, range 27-57) with VUA obstruction in their transplanted kidneys were treated by percutaneous nephrostomy and endoscopic incision. After the anastomosis was completely cut, two JJ stents were placed in the ureter for 4-6 weeks. During the follow-up, serum urea, creatinine and uric acid levels were measured, and urine culture, ultrasound examination and washout renal scintigraphy were performed every month for the first 6 months, then every 3 months.

RESULTS

In all, 12 procedures of endoureterotomy were performed and all procedures resulted in successful incision of the obstruction. There were no complications during or after the procedures. The retrograde and antegrade endoureterotomies were performed with four procedures in two patients and eight procedures in six patients, respectively. At a mean (range) follow-up of 16 (4-45) months, five of the eight patients had ureteric patency and stable renal function. In three patients there was a recurrence of obstructive uropathy, immediately after JJ stent removal, which finally required open surgical correction.

CONCLUSIONS

Percutaneous nephrostomy and endoscopic incision is safe and effective for obstruction of VUA in transplanted kidney, and it can be the initial therapy for ureteric obstruction in transplanted kidneys; however, open surgical reconstruction should be considered if the initial endoscopic incision procedure fails.

Endoureterotomy for Treatment of Primary Obstructive Megaureter in Children

PURPOSE

To describe a new approach to the treatment of primary obstructive megaureter (POMU) using endoscopic endoureterotomy. The results obtained with this technique are reviewed with long-term follow-up.

PATIENTS AND METHODS

A total of 47 children (mean age 3.7 years) with 52 POMU units and a history of failed conservative management underwent endoureterotomy of obstructed juxtavesical and intramural ureter. A 3F Double-J ureteral stent was introduced up to the obstructed segment of ureter. Then a zebra catheter was inserted into the affected ureter beside the stent, followed by a neonatal-size ureteroscope. Following delineation of the length of the narrowed portion of the ureter, a guidewire with a plastic sheath replaced the zebra catheter. A longitudinal incision was made through the detrusor muscle at the 6 o'clock position, leaving the bladder adventitia untouched. The Double-J stent was left in place, while its distal tip was fixed by long nylon suture and single knot to the external genitalia to permit easy removal 1 week after the procedure.

RESULTS

With a mean follow-up of 39 months (range 14-62 months), no leakage, ureteral-orifice obstruction, or reflux was observed. The postoperative success rate was 90% (47 of 52 ureters), defined as resolution or decrease in hydroureteronephrosis and improvement or stability of renal function determined by renal scan. In 37 ureterorenal units (71%), there was complete resolution of hydroureteronephrosis.

CONCLUSIONS

On the basis of previous studies demonstrating the value of endoureterotomy with stenting for the treatment of benign ureteral strictures in adults, we developed a modified endoscopic approach for the treatment of POMU and applied this technique in meticulously selected cases. Our results showed that this approach is a valid option for the treatment of children with POMU.

[Should double J catheter be systematically considered in renal transplantation?]

Protection of urinary anastomoses using a ureteral catheter is a frequent option in urology but such use in a systematic manner remains debated in renal transplantation. Some consider that systematic insertion of a double J sound decreases the incidence of ureteral complications (fistula and stenosis). Others who prefer a selective use in some situations with a related risk consider that the implementation of a double J catheter cannot compensate a technical defect. It is even responsible for specific complications (infections, incrustation, haemorrhages); it increases implantation costs and is useless in more than 90% of the cases. This article analyses the risks related to systematic implementation of a double J catheter in Lich-Gregoir ureterovesical anastomoses for renal transplantation, together with the related costs and the infectious risk. The benefits in terms of prevention of ureteral complications are evaluated.

Evaluation of the duration of ureteral stenting following endopyelotomy: Animal study

BACKGROUND

The purpose of the present paper was to evaluate whether it is possible to reduce the duration of ureteral stenting following endopyelotomy, and thus reduce side-effects.

METHODS

Seventeen pigs were used. They were distributed at random into three groups. The study was divided as follows: phase I included baseline study of the urinary system and the creation of a ureteropelvic junction obstruction (UPJO) model. Phase II, 1 month later, consisted of diagnosing UPJO, Acucise endopyelotomy of the same, and the placement of a ureteral stent. Ureteral stents were left in situ for 1 week in group I, for 3 weeks in group II and 6 weeks in group III. Phase III, 3 months after treatment, consisted of follow up and post-mortem studies of the animals. The following procedures were carried out during each phase: ureteropelvic junction (UPJ) diameter measurement, ultrasound percutaneous and endoluminal studies, urine culture and determination of blood urea and creatinine levels.

RESULTS

On removal of the stent, the presence of urinoma was observed in two animals in group I. There were statistically significant differences between group I and III with regard to evolution of the internal diameter of the UPJ. However, the least severe histological lesion at the UPJ level was found in group II.

CONCLUSIONS

Ureteral stent placement for 1 week is insufficient in order to assure correct healing and evolution of the UPJ following endopyelotomy. Stenting for 3 weeks is effective, and it is not necessary to extend stenting time to 6 weeks. Endoluminal ultrasound is of great use in determining the effects of endourological techniques in the ureter and the retroperitoneal space. It is also useful for deciding which therapeutic technique to use, and for inserting the Acucise in order to prevent iatrogenic problems.

Comparative study of ureteral stents following endoureterotomy in the porcine model: 3 vs 6 weeks and 7F vs 14F

The aim of the study was to determine the optimal stent size and stenting duration following retrograde endoureterotomy of experimental ureteral strictures. Twenty healthy Large White female pigs were randomly divided into four groups, depending on stent size (7F vs 14F) and stenting duration (3 weeks vs 6 weeks). Three additional pigs were used as the control group. The internal ureteral diameter was measured 2 cm below the lower pole of the right kidney. Histopathological changes of the urinary tract, ultrasonographic and fluoroscopic studies, urine culture, and serum urea and creatine levels were analyzed during the different phases of the study. The study was divided into three phases. Phase I included premodel documentation of the normal urinary tract and laparoscopic ureteral stricture creation. During the second phase 1 month later, the diagnosis and endourologic treatment of strictures were performed. Phase III began 4 weeks after stent removal; follow-up imaging studies and postmortem evaluation of all animals were performed. Ureteral strictures developed in all animals 4 weeks after model creation. Results from ureteral diameter measurements and pathological studies revealed no statistically significant intergroup differences. However, prevalence of urinary infection proved to be directly related to stent size (14F) and permanence (6 weeks). The chi square results suggest a statistically significant relationship between the urinary tract infection and recurrent strictures (alpha = 0.046). We recommend the use of 7F stents for a period of 3 weeks or less, as these are more easily positioned and result in the reduction of secondary side effects (lower infection rate, less intramural ureteral lesions). A significant relationship between urinary tract infection and stricture recurrence was found in this experimental study.

Smooth-muscle regeneration after electrosurgical endopyelotomy in a porcine model as confirmed by electron microscopy

BACKGROUND AND PURPOSE

Endopyelotomy is the preferred treatment for ureteropelvic junction (UPJ) obstruction because of its short operating time, limited morbidity, fast recovery, and reasonable efficacy. We used tissue and immunohistochemistry staining and electron microscopy to look at the muscle regeneration following an endopyelotomy incision in a porcine model.

MATERIALS AND METHODS

Bilateral electrosurgical endopyelotomy was performed in six domestic pigs with placement of 7F 20-cm Percuflex double-J stents for up to 4 weeks, and urinary tracts were harvested at 3 or 5 months. Specimen evaluation included tissue staining with hematoxylin-eosin, Masson's trichrome, and Verhoeff's iodine and Van Gieson solution; histochemical staining for smooth-muscle actin, desmin and myosin staining, and electron microscopy. Each specimen was assigned a "healing" score of 0 (normal) 1 (slight changes), 2 (mild changes), or 3 (severe changes). The fibrosis score was based on six factors: muscle layer fibrosis, lamina propria fibrosis, amount of granulation tissue present, new deposits of collagen, fibrosis in the periureteral fat, and presence of myofibroblasts. The muscles were characterized with immunohistochemistry and electron microscopy.

RESULTS

At both 3 and 5 months, the urothelium was healed, and the lamina propria was healed with focal loss. By 3 months, smooth-muscle bundles bridged the defect, and by 5 months, the whole defect was covered. Smooth muscle cells were evident by electron microscopy by 3 months, and actin and myosin could be detected by immunohistochemistry. Desmin-positive cells accounted for 50% of the population at 3 months and 40% at 5 months. The regenerated smooth-muscle bundles were oriented in different directions and intermingled with fibrous tissue. They could be distinguished easily from normal ureter under the microscope.

CONCLUSION

Verifiable, functional smooth-muscle bundles bridge the endopyelotomy defect by 3 months, as confirmed by immunohistochemistry staining and electron microscopy.

[Endourologic treatment of ureteral strictures. Experimental comparative study]

OBJECTIVES

To compare efficacy and efficiency of two different endourological therapies for ureteral stricture, and to evaluate pathological reactions of the ureters following both endourological techniques.

MATERIAL AND METHODS

Ten pigs underwent experimental induction of ureteral stricture. Four weeks later, ureteral strictures were demonstrated by imaging techniques. Animals were divided in two groups, according to the received therapy: -Group I. (5 pigs), endoballoon rupture endoureterotomy. -Group II (5 pigs), Acucise balloon endoureterotomy. Ureteral stents were placed for 3 weeks following endoureterotomy. Animals were followed up four weeks after ureteral stents retrieval.

RESULTS

In all cases, ureteral stricture was proved four weeks after model induction. In one case from each group, it was needed a second balloon dilatation to achieve complete endoureterotomy. Leading to ureteral restenosis, stent migration occurred in one animal from group I. Success was achieved in 80% of cases from group I, and 100% of cases from group II.

CONCLUSIONS

Our results suggest that both endourological therapies are effective. Nevertheless, a higher efficiency was proved with Acucise endoureterotomy. Our pathological evidences do not support Davis's studies on ureteral healing following endoureterotomy.

Ureteroscopic endoureterotomy

OBJECTIVE

To highlight the current status of ureteroscopic endoureterotomy (UE) by reporting extensive experience with the endoscopic management of ureteric strictures, with special emphasis on factors determining success, and by reviewing publications on the minimally invasive management of ureteric strictures.

PATIENTS AND METHODS

The study comprised 50 patients (mean age 53 years, range 18-85, equal sex distribution) with ureteric strictures of varying causes; all had their stricture treated endoscopically. The follow-up was 0.5-9 years; 10 patients with recurrent strictures had two ipsilateral stents placed to try to improve the outcome, and eight patients with completely obliterating strictures were treated by ureteroscopic re-canalization.

RESULTS

The site of stricture had no bearing on the eventual outcome. Patients with uretero-enteric and malignant strictures did not fare so well. The most important predictor of failure was the length of the stricture, with failure in all seven patients with strictures of > 2 cm. In the 10 patients treated with two ipsilateral stents, eight were successful, which was very promising considering that these patients had recalcitrant strictures and placing one stent had previously failed. The overall success rate was 74%.

CONCLUSION

UE has become the procedure of choice for the initial management of ureteric strictures. Simple balloon dilatation is also effective in certain situations. The characteristics of the stricture often govern the eventual outcome. In properly selected cases success rates of approximately 75% can be expected.

The use of stents in contemporary urology

PURPOSE OF REVIEW

Ureteral stents are a mainstay of today's urological armamentarium. This review critically evaluates the recent literature and provides a concise summary of the use of stents in urology today. While stents are used in many reconstructive urologic procedures, this review focuses on the use of stents in urolithiasis as it pertains to ureteroscopy, shockwave lithotripsy, and ureteropelvic junction obstruction.

RECENT FINDINGS

Ureteral stents are associated with irritative symptoms, hematuria, infection, and encrustation. A new validated quality of life and impact questionnaire has been developed and has shown that 76% of patients suffer at least some type of morbidity related to the stent. Many studies in the recent literature have re-examined our use of stents today. For example, concepts regarding stenting following ureteroscopy, before shockwave lithotripsy, and following endopyelotomy have undergone an evolution based on the results of randomized, prospective studies.

SUMMARY

The ureteral stent is an invaluable urological tool and its indications are evolving as are new stent technologies to improve patient care and comfort.

Anatomic and physiologic considerations in ureteroscopy

The successful and safe implementation of ureteroscopic techniques depends on considerations of anatomy and physiology. Combining knowledge of the drainage system of the kidney with its vascular supply, predictive patterns of incisions can be applied within the collecting system to safely avoid vascular injury. In addition, awareness of the variation in normal and pathologic anatomy and physiology is key to effective interventions. An appreciation of the impact of ureteroscopy on normal anatomy and physiology can prevent complications and promote improved therapeutic outcomes.

Pediatric ureteroscopy

Endoscopic evaluation and management of the diverse conditions involving the upper urinary tract of children is now feasible and has been shown to be safe and efficacious. This modality should be considered an essential part of the armamentarium of any urologist involved in the care of children. Continued technological advances will allow the indications for pediatric ureteroscopy to evolve. The benefits of minimally invasive surgery that have been proved in adult patients can now be offered to pediatric patients. A thorough knowledge of available equipment and the anatomic and physiologic differences of pediatric patients will ensure a successful outcome with minimal morbidity.

Update On Minimally Invasive Management of Ureteral Strictures

PURPOSE

To review the role of minimally invasive management in ureteral stricture disease.

MATERIALS AND METHODS

A literature search was performed on the MEDLINE database through 2002 concerning endoscopic treatment of patients with ureteral strictures.

RESULTS

Many endourologic methods are available for ureteral strictures. Ureteral dilation may be accomplished in most cases, with various rates of success depending on stricture etiology, location, and length. Endoureterotomy also leads to long-term patency in properly selected cases and appears to be superior to dilation alone.

CONCLUSIONS

Significant advances in technique and technology have improved our ability to treat ureteral strictures without the need for open surgery in most patients.

Laparoscopic Repair of Ureteral Injuries

STUDY OBJECTIVES

To evaluate the laparoscopic approach for repairing ureteral injuries, and assess the effect of ureteral dissection (ureterolysis) on tissue healing.

DESIGN

Randomized animal study (Canadian Task Force classification I).

SETTING

Biological Resources Unit, Cleveland Clinic Foundation.

SUBJECTS

Ten pigs.

INTERVENTION

In all animals, the pelvic segment of the right ureter was completely dissected off the pelvic sidewall and peritoneum. In group A, both pelvic ureters were divided with scissors and repaired over a stent; in group B the ureters were coagulated and anastomosis was performed after resection of the necrotic segment. Laparoscopic intracorporeal suturing techniques were used for end-to-end ureteral anastomosis.

MEASUREMENTS AND MAIN RESULTS

All animals survived without complications. Ureteral stents were removed 4 weeks after repair. Creatinine level and retrograde pyelogram performed before injury and 12 weeks after repair were compared. At necropsy anastomoses were evaluated for leak, pressure flow studies, and histopathology. All anastomoses were patent with no leak. Although serum creatinine level increased significantly after repair (p = 0.001), this increase never reached levels found in renal failure, and all animals continued to do well and have good appetite (mean increase in body weight 20.3 +/- 6.2 kg). Mild hydronephrosis was diagnosed in three kidneys, all on the right side. Mild ureteral dilatation occurred bilaterally; it was significant on the right side (3.8 +/- 3.8 mm, p = 0.05) but not on the left (1.7 +/- 2 mm, p = 0.3). Results of pressure flow studies did not reveal significant obstruction at anastomoses. Healing around the dissected right ureter was marked with dense fibrosis, adhesions, and scar formation. On histopathology the right ureter showed more urothelial abnormalities than the left, with marked fibrosis and sclerosis in the muscularis and adventitial layers.

CONCLUSION

Ureterolysis may interfere with the healing process of ureteral injuries by increasing fibrosis and adventitial scarring. Laparoscopic repair of these injuries is feasible and safe.

Cold-knife endoureterotomy for nonmalignant ureterointestinal anastomotic strictures

OBJECTIVES

To evaluate the long-term results of cold-knife incision (CNI) of nonmalignant ureterointestinal anastomosis strictures (UASs) after urinary diversion in a consecutive series of patients.

METHODS

Since 1994, we have evaluated retrospectively 40 patients with 43 UASs, who were primarily treated with CNI (group 1). Six patients from group 1 with 7 UASs who failed primary CNI comprised group 2. After placement of an 8F nephrostomy tube, a 0.035-inch guidewire bypassed the stricture in an antegrade fashion under guidance of a centrally opened ureteral catheter (5F). A wire-mounted cold-knife was pulled through the strictured area in retrograde fashion under fluoroscopic control. Postoperatively, an 8 to 12F stent was left indwelling for 6 to 12 weeks. Successful treatment was defined as radiographic and scintigraphic resolution of obstruction and symptomatic relief.

RESULTS

In group 1, after removal of the stent, the ureteroenteric area remained patent in 26 (60.5%) of 43 UASs during a follow-up period of 38.8 months (range 12 to 85). The success rate at 1, 2, and 3 years was 86%, 67.8%, and 60.5%, respectively. In group 2, no success occurred. The diameter and length of the stricture, kidney function, hydronephrosis grade, presence of urinary infection at presentation, past CNI or radiotherapy, number of incisions with the cold-knife, and premature appearance of the anastomosis stricture were statistically significant influences on the outcome (P <0.05). Considering only the patients (n = 8) with the most favorable predictive factors (interval to stricture formation 12 months or longer, stricture length 1.5 cm or less, and hydronephrosis grade I-II), the success rate was 100%. No complications were observed.

CONCLUSIONS

CNI is an effective and minimally invasive treatment for primary UASs, providing durable results compared with other modalities used for endoureterotomy, and should be considered as an initial approach. The selection of patients with the most favorable prognostic factors leads to excellent results. As a secondary procedure, CNI was not successful.

Is a 2-week duration sufficient for stenting in endopyelotomy?

PURPOSE

Internal stenting is an integral part of endopyelotomy. Studies in animals show good healing after 1 to 2 weeks of ureterotomy. Inherent stent related problems warrant a minimum possible duration of stenting without compromising the results of endopyelotomy. We performed a prospective randomized trial to evaluate the optimum duration of stenting after endopyelotomy.

MATERIALS AND METHODS

A total of 57 consecutive patients with primary ureteropelvic junction obstruction were randomized to undergo 7/14Fr internal endopyelotomy stent placement for 2 (group 1) and 4 (group 2) weeks. A symptom based questionnaire was administered to all patients at stent removal. Followup was done with diuretic scanning at 3, 6, 9 and 12 months and then yearly, and thereafter with diuretic renography.

RESULTS

In each group 26 patients were available for evaluation. The 2 groups were comparable in terms of age, sex, symptoms and ipsilateral glomerular filtration rate. Mean followup was 22.3 (range 12 to 36) and 21.3 months (range 12 to 35) in groups 1 and 2, respectively. At the end of 1 year 24 group 1 (92.3%) and 23 group 2 (90.3%) patients had an improved drainage pattern. This difference was not significant. Stent related symptoms were present in a good proportion of patients in groups 1 and 2 but there was a significant difference in the incidence of urinary tract infections (11.5% versus 38.1%, p = 0.04). Of the group 2 patients 64% preferred 2 weeks of stenting.

CONCLUSIONS

Two weeks seems to be a sufficient duration to allow functional restoration across the ureteropelvic junction after endopyelotomy and decrease stent related complications.

Treatment of iatrogenic postoperative ureteral strictures with Acucise endoureterotomy

OBJECTIVES

To determine factors influencing the outcome of Acucise endoureterotomy in patients with iatrogenic postoperative ureteral strictures after different open surgical procedures.

MATERIAL AND METHODS

Acucise endoureterotomy was performed in 18 patients with ureteral strictures after pyeloplasty (n = 5), renal transplantation (n = 5), ureteroenteric anastomosis (n = 3), calicoureterostomy (n = 1), ureterocystoneostomy (n = 1), hysterectomy (n = 1), ureterorenoscopy (n = 1) and transurethral resection of the ureteral orifice (n = 1). Success was determined as relief of clinical symptoms, improvement of renal function or improvement of radiographic findings.

RESULTS

The overall success rate was 61% (mean follow-up: 21.5 months). Six out of 18 patients showed relevant side effects. Neither the localization of the stricture nor the duration of postoperative ureteral stenting but the length of the stricture had influence on the postoperative outcome. Decreased renal function to less than 25% of the total function was always associated with failure of the treatment. The time period between the ureteral injury and the appearance of the ureteral stricture had influence on the outcome of the treatment.

CONCLUSIONS

Acucise endoureterotomy is effective in the treatment of postoperative ureteral strictures, but only in selected cases. The selection criteria are the time period from the primary operation to the appearance of the stricture (>6 months), the length of the stricture (<1.5 cm) and the renal function (>25% of the total function). In other cases, open surgical treatment of the ureteral stricture may provide better results.

The role of Acucise endopyelotomy in the treatment of ureteropelvic junction obstruction

OBJECTIVE

Open surgical pyeloplasty has been the gold standard for the correction of ureteropelvic junction obstruction (UPJO). Endourological management of UPJO has gained increased acceptance, with reported success rates of 57-87%. It has been suggested that Acucise endopyelotomy (AE) should be the procedure of choice for patients with UPJO. The aim of this study was to assess the effectiveness of AE in the treatment of UPJO and the factors contributing to surgical outcome.

MATERIALS AND METHODS

Forty-two patients (34 primary, 8 secondary UPJO) underwent AE between June 1995 and December 1999. Presenting symptoms were; pain 34 (80.9%), UTI 10 (23.8%) and haematuria 5 (11.9%). Preoperative evaluation included ultrasound and/or intravenous urogram with diuretic renography. Hydronephrosis was graded in 36 patients. Of these 4, 14, 9 and 9 had grade I, II, III and IV hydronephrosis, respectively. Twenty-four patients were stented prior to endopyelotomy and one required nephrostomy. Overall (true) success was defined as clinically pain free and radiologically no evidence of obstruction on diuretic scan.

RESULTS

The average operating time was 45 min and mean hospital stay was 2.7 days. Mean follow-up was 27 months (range 6-55). The objective success rate was 52% and the subjective success rate was 64%. A total of 19 patients (45.2%) had long lasting clinical and radiographic treatment success. Three (7%) patients required nephrectomy and five (12%) underwent open pyeloplasty. Success rate for grade I/II hydronephrosis was 55.5% and only 27.7% with grade III/IV hydronephrosis. Normal renograms were found in 12 (48%) of those with perioperative extravasation compared to three (25%) without. Only one of the eight patients with secondary UPJO had a normal post-operative renogram. Size or type of stent used had no effect on surgical outcome. The substandard results were noted in patients with grade III/IV hydronephrosis, poor pre-operative renal function, secondary UPJO and without perioperative extravasation.

CONCLUSIONS

Acucise endopyelotomy is a safe and minimally invasive procedure for the management of UPJO. Although the results of AE are suboptimal, its lower degree of invasiveness makes it reasonable choice for first-line treatment. Careful selection of patients will improve the results of AE, although multicentre randomized trials are needed to make a valued comparison with other techniques.

Endoscopic ureteral incision using the holmium:YAG laser

BACKGROUND

We reviewed the results of endoscopic ureteral incision for benign ureteral stricture, ureteropelvic junction obstruction and ureteroenteroanastomotic stricture using the holmium laser.

METHODS

We carried out endoscopic ureteral incision using the holmium laser through an 8-Fr semirigid or 6.9-Fr flexible ureteroscope on 17 ureters in 15 patients. Balloon dilatation was not necessary before insertion of the ureteroscope. The stricture was incised with the holmium laser using a 200-365 microm fiber through the working channel of the ureteroscope. After completion of the incision, a 12-Fr double-J catheter was left for 6 weeks. Thereafter patients were followed by renal scan and/or ultrasound and excretory urography at 3-6 month intervals.

RESULTS

The mean operative time was 65 min (18-135 min). The stricture resolved completely in 86.7% of cases at an average follow up of 20.5 months (11-32 months).

CONCLUSIONS

The holmium laser endoscopic ureteral incision was associated with a good outcome in our series. We recommend this procedure to be employed initially because it is less invasive and has a favorable outcome.

Ureteropelvic junction obstruction. Retrograde endopyelotomy

The modern day treatment of UPJO with retrograde endopyelotomy continues to evolve as experience and knowledge progress. Use of the straight lateral incision and selective use of spiral CT angiogram has refined treatment decisions with retrograde endopyelotomy further. The authors' decision-oriented approach offers guidelines for the practicing urologist. Ultimately, it is up to the urologist and the patient to select the best approach for each clinical scenario.

Endourological treatment of ureteroenteric strictures: efficacy of Acucise endoureterotomy

PURPOSE

The Acucise endoureterotomy balloon catheter has proved to be a safe and effective alternative to open surgery for the management of ureteropelvic junction obstruction and benign ureteral stricture disease. The established management of ureteroenteric strictures following urinary diversion is open surgical revision. There are few reports evaluating the efficacy of Acucise endoureterotomy in patients with ureteroenteric strictures.

MATERIALS AND METHODS

The Acucise cutting balloon catheter was used to treat 9 patients with 12 ureteroenteric strictures 2 cm. or less in length. Median time from diversion to stricture was 48 months (range 13 to 192). Success was defined as resolution of symptoms and radiographic confirmation of patency.

RESULTS

Recurrence of malignancy accounted for failure in 1 patient with bilateral strictures. Of the remaining 10 benign strictures 7 (70%) required open revision or serial stent changes. The remaining 3 strictures in 2 patients have remained patent at 30 and 18 months of followup for a success rate of 30%. There were no perioperative or operative complications. Mean followup was 9 months after Acucise treatment before intervention was necessary.

CONCLUSIONS

Acucise endoureterotomy for ureteroenteric strictures following urinary diversion is a low morbidity procedure. Although the success rate is only 30%, Acucise endoureterotomy offers an alternative to immediate open surgical revision.

Optimum duration of splinting after endopyelotomy

OBJECTIVE

Endopyelotomy is a well-accepted modality of treatment for pelviureteral junction (PUJ) obstruction, but the time period of stenting is debatable. The present study was aimed at evaluating the optimum duration and effectiveness of splinting after endopyelotomy.

PATIENTS AND METHODS

Twenty-nine consecutive patients with primary PUJ obstruction were randomized to have an external splint (for economic reasons) for 2 weeks or 4 weeks. Thirteen patients in each group were available for evaluation. The groups were comparable in age, sex, symptoms, and preoperative glomerular filtration rate (GFR). All patients underwent antegrade endopyelotomy with placement of an 8F-12F polyethylene splint across the PUJ. A nephrostogram was performed after removal of splint at 2 or 4 weeks. Nondraining units were managed by putting in a 6F double-J stent for 6 weeks and considered failures. Patients were evaluated at 3, 6, and 12 months for symptomatic improvement, change in GFR, and drainage pattern on a diuretic renogram.

RESULTS

At 1 year, a nonobstructed curve pattern was seen in 70% and improvement in GFR in 54% of the patients in the 2-weeks group, whereas in the 4-weeks group, these values were 54% and 39%, respectively. All patients in the 4-weeks group and 90% of those in the 2-weeks group were symptom free at 1 year of follow-up. Morbidity in terms of tube-related complications was comparable.

CONCLUSION

Two weeks of splinting is as effective as 4 weeks in the successful outcome of endopyelotomy.

Endobrst: simple and safe is best

Minimal-access treatment for ureteropelvic junction (UPJ) obstruction is becoming increasingly complex. Is there still a place for the simple procedure of balloon dilatation? To examine the symptomatic and renographic results of patients at least 6 months after balloon disruption of an obstructed UPJ, we carried out a prospective audit of outcome as judged by DTPA renograms and clinical follow-up. The procedure has been performed on a total of 21 renal units (20 patients) with follow-up of 6 to 30 months (mean 22 months). Of these, 18 (86%) were asymptomatic at 3 months, although this success rate dropped to 17 (81%) by 6 months. Renographic split function improved in 11 renal units, and excretion improve in 14. Perioperative complications were few and associated with stent insertion. Three of the patients in whom the procedure failed went on to nephrectomy (14%); all had poor renal function (split <20%) at presentation. Although the quoted success rates are lower for endoluminal balloon rupture of stenosis treatment than open pyeloplasty, the former technique has significantly less morbidity. Our nephrectomy rate reflects our less than ideal early patient selection, and our balloon dilation technique is not recommended as a salvage procedure for patients in whom nephrectomy is inevitable. The learning curve is quick to climb, and this is a fundamentally simple procedure with medium-term results that remain encouraging.

Ureteral repair with titanium staples: comparison with suture closure

OBJECTIVES

Vascular closure staple (VCS) clips made of titanium were initially developed for microvascular anastomoses with little knowledge of their effectiveness in larger tubular tissue structures. This study compares VCS clips and sutures in the closure of longitudinal ureterotomy incisions.

METHODS

In 9 pigs, 1-cm-long anterior, longitudinal ureterotomy incisions were randomly assigned to closure with either 4-0 interrupted polyglactin sutures or VCS clips.

RESULTS

Clip closure was significantly faster (74+/-28 versus 534+/-182 seconds). All 18 ureters were patent and without signs of leakage, calculus formation, or stenoses after 3 months. Clip closure resulted in slightly but not statistically significantly less narrowing of the duct lumen, but there was no difference in wall thickness at the repair site. At histologic examination, all 18 incisions healed without signs of acute inflammation or marked fibrosis.

CONCLUSIONS

Ureterotomy closure with VCS clips results in wound healing that is as effective as suture closure, with a comparable degree of narrowing. The time required for clip closure is only about 1/7 that required for suture closure.

Update on interventional uroradiology

From its humble beginnings as a method of expediently decompressing the obstructed kidney, the field of interventional uroradiology has evolved in the hands of urologists and interventional radiologists to a means of addressing myriad problems in the urinary tract and has changed the day-to-day practice of urology. The foundation of interventional uroradiology is the creation of an appropriate entry into the urinary system. After a review of this basic procedure, extensions of the technique and new applications of emerging technology are reviewed.

Comparative ureteral microanatomy

Several animals have been used as models for experimental upper urinary tract surgery. Although minipigs have recently gained favor because their upper urinary tract is grossly similar to that of humans, the ureteral microanatomic features of the two species have not been compared. We evaluated the histologic features of human and animal ureters in order to provide addition information regarding experimental models for upper urinary tract surgery. Cross-sections of upper, middle, and lower ureteral segments from human autopsy specimens and animals (farm pig, minipig, dog, sheep, rabbit, and rat) were evaluated after preparation with Masson's trichrome stain. Morphology, computer-assisted morphometry, linear micrometry, and point-count estimation of smooth muscle/connective tissue ratios were assessed. The epithelium was remarkably consistent across all species, both morphologically and in terms of absolute size. The lamina propria was highly vascularized in all species, but the compactness varied with the overall ureteral dimensions. In the muscularis, the relative size and the percentage composed of smooth muscle differed widely among species, as did the ratio of muscularis to lamina propria cross-sectional surface area. Among the species evaluated, the sheep, farm pig, and minipig ureters were the best histologic approximations of the human ureter. Given the difficulties with manipulation of the small sheep ureter, the minipig and farm pig models appear to be optimal for experimental research on upper urinary tract surgery by an endourologic approach.

Use of ureteral stents after endopyelotomy

Despite the widespread practice of endopyelotomy for the management of ureteropelvic junction obstruction, the optimal conditions for ureteral healing after endoincision remain largely untested. Current recommendations for the use of large-caliber graduated endopyelotomy stents and a 6-week duration of stenting are being challenged by recent reports of successful outcomes with the use of standard, small-caliber ureteral stents and early stent removal. Moreover, improvements in stent design have led to the development of endopyelotomy stents with improved biocompatibility, enhanced case of insertion, and fewer adverse effects.

Physiology and evaluation of ureteropelvic junction obstruction

Ureteropelvic junction (UPJ) obstruction is not a single anatomic entity but rather a set of processes with multiple causes. In the obstructed system, histologic changes are apparent that have implications for healing. The role of crossing vessels In UPJ obstruction and its treatment is of growing interest. Various methods are available to assess the functional characteristics of the UPJ, of which the diuretic renogram, Whitaker perfusion test, and Doppler ultrasound resistive index may be the most useful. The treatment must be individualized according to the patient's symptoms, the status of renal function, and the potential complications of intervention.

Long-term follow-up of Acucise incision of ureteropelvic junction obstruction and ureteral strictures

OBJECTIVES

There are few data on the long-term effectiveness of various endoureterotomy procedures. One such technique for the treatment of ureteral strictures and ureteropelvic junction (UPJ) obstruction utilizes a recently developed ureteral cutting balloon catheter, Acucise. This device may be used under fluoroscopic guidance alone, which significantly reduces operating time. The purpose of this study is to determine the long-term efficacy of the Acucise balloon in treatment of ureteral strictures and UPJ obstruction.

METHODS

Fifteen patients have been treated with the Acucise balloon, with an average follow-up of 21.6 months. Five of the patients have been followed for more than 2 years, and 11 of the patients had greater than 1 year follow-up.

RESULTS

The overall success rate, defined as resolution of obstruction radiographically or disappearance of symptoms, or both, was 73%, with only 4 overt failures. All but one of the procedures were completed in 45 minutes or less, and 13 of the 15 patients were treated as outpatients. There were two significant complications. Seventy-five percent (3 of 4) of the treatment failures occurred within the first 4 months following original procedure. Of the 4 total failures. 2 patients had ureteral strictures greater than 2 cm in length, which were likely ischemic in nature secondary to previous surgeries. One patient, with a primary UPJ obstruction, was found to have a crossing vessel at subsequent open pyeloplasty.

CONCLUSIONS

The Acucise cutting balloon offers the urologist a rapid and effective alternative for the management of ureteral strictures and UPJ obstruction. In our experience, early results (3 to 4 months) are usually indicative of long-term success. Proper patient selection may further improve long-term results of this simple, innovative technique.

Evaluation of optimal stent size after endourologic incision of ureteral strictures

The stent size necessary to promote optimal ureteral healing after an endoureterotomy is not known. We compared healing of an endoureterotomy over a 7F indwelling ureteral stent with healing over a 14F endopyelotomy stent. A midureteral stricture was created in each of 25 anesthetized female minipigs using an electrified stone basket passed retrograde. Six weeks later, the stricture was incised with a 24F cutting balloon device. Twenty pigs were randomized to receive a 7F or a 14F stent; four control pigs received neither incisions nor stents. At 1 week, a radiograph was performed to confirm proper stent position, and the stents were removed. At 3 months, a retrograde ureterogram was performed, and the ureters were examined grossly and harvested for histologic studies. Two of the ten pigs in each study group developed a recurrent stricture. The use of a 14F stent provided no advantage over the use of a smaller, more easily positioned 7F stent.

Changing incidence and etiology of iatrogenic ureteral injuries

In the last decade there have been major advances in endoscopic surgery including ureteroscopy and laparoscopy, both of which may cause ureteral injury. We sought to determine if increased use of these procedures affected the frequency and nature of major iatrogenic ureteral injuries managed at our medical center. From 1980 to 1984 we treated 8 patients with such injuries compared to 19 patients treated from 1985 to 1989. The most recent period corresponded to the institution of ureteroscopy and the use of more aggressive laparoscopic procedures. Of the patients 14 sustained injuries at our center while 13 were referred from other institutions. Between 1985 and 1989 the incidence of injuries per total hospital admissions at risk increased from 4 to 11 per 10,000 (p = 0.0067), the incidence of urological injuries increased from 4 to 23 per 10,000 (p = 0.0071) and the incidence of injuries occurring in gynecologic patients increased from 13 to 41 per 10,000 admissions (p = 0.0385). There was no difference in the incidence of injuries in the general surgical population. From 1980 to 1984 no laparoscopic or ureteroscopic injuries occurred. However, from 1985 to 1989, 25% of gynecologic injuries occurred during laparoscopy and 70% of urological injuries were sustained during ureteroscopic procedures. Depending on the extent of the injury, patients were initially treated with either endourological or open surgical procedures. Good results were obtained in the majority of cases. Contemporary therapeutic strategies for treating patients sustaining ureteral injuries are discussed.