Cold-knife endoureterotomy for nonmalignant ureterointestinal anastomotic strictures

ADULT UROLOGY

COLD-KNIFE ENDOURETEROTOMY FOR NONMALIGNANT URETEROINTESTINAL ANASTOMOTIC STRICTURES VASSILIS POULAKIS, ULRICH WITZSCH, RACHELLE DE VRIES,

AND

EDUARD BECHT

ABSTRACT 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. UROLOGY 61: 512–517, 2003. © 2003, Elsevier Science Inc.

T

he incidence of ureterointestinal anastomosis stricture (UAS) after urinary diversion ranges from 1% to 9%.1,2 The reference standard for treating UASs is open ureteral reimplantation, but this is associated with considerable morbidity and prolonged hospitalization.3– 6 In recent decades, endoscopic methods have been established as alternative treatments. These include chronic stents, balloon dilation, and endoureterotomy. However, significant morbidity

can be associated with indwelling stents.7 The long-term success rate after the first percutaneous dilation was only 16%.8 Endoureterotomy showed better results, ranging from 30% to 100% using different modalities.5,8 –11 Our success with cold-knife incision (CNI) has been encouraging,12 and the present study reviewed our long-term results with this experience.

From the Departments of Urology and Pediatric Urology, Krankenhaus Nordwest Teaching Hospital of Johann-WolfgangGoethe-University Frankfurt, Frankfurt/Main, Germany Reprint requests: Vassilis Poulakis, M.D., Clinic for Urology and Pediatric Urology, Nordwest Hospital, Steinbacher Hohl 2-26, Frankfurt am Main D-60488, Germany Submitted: June 19, 2002, accepted (with revisions): October 23, 2002

Between September 1994 and May 2001, 40 patients (26 men and 14 women) with 43 UASs were primarily treated with CNI (group 1). The mean patient age was 67.8 years (range 58 to 78). In 6 patients (4 men and 2 women) in group 1 with seven UASs, the initial CNI failed; these patients underwent a second CNI (group 2). The reasons for performing urine diversion were muscle invasive transitional cell carcinoma (n ⫽ 30), radiogenic low-capacity bladder (contracted bladder oc-

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MATERIAL AND METHODS

0090-4295/03/$30.00 doi:10.1016/S0090-4295(02)02503-7

curred as a late complication after radiotherapy for Stage Ib cervical carcinoma, n ⫽ 3), interstitial cystitis (n ⫽ 3), neurogenic bladder (n ⫽ 2), and locally advanced prostate cancer (Stage pT4a, pN1, M0, n ⫽ 2). The patients with prostate carcinoma had been treated with adjuvant radiotherapy (40 Gy). Only 16 (40%) of 40 patients with UASs underwent urinary diversion at our center. In our series, 29 (72.5%) had an ileal conduit (Bricker urinary diversion with ureter implantation using the technique of Bricker in 27 and the technique of Wallace in 2),13 3 (7.5%) had a colon conduit (ureter implantation using the technique of Goodwin-Hohenfelner),14 and 8 (20%) had a Hautmann ileum neobladder (ureter implantation using the technique of Abol Enein and Ghoneim15 in 5 and the technique of Le-Duc in 2).13 Most patients (n ⫽ 23, 57.5%) had no complaints. The main presenting symptoms were flank pain (42.5%, n ⫽ 17) and urinary infection (30%, n ⫽ 12). In all patients, hydronephrosis was present. Tumor metastasis or local recurrence was preoperatively excluded with computed tomography, urinary cytology, biopsies obtained preoperatively from the strictured area. A percutaneous nephrostomy catheter was placed preoperatively in all obstructed renal units and antegrade pyeloureterography was performed. Twenty-two strictures were “partial” or high pressure (mean stricture length 1.8 cm, range 1 to 2.6) and 16 were “complete” (average stricture length 2.1 cm, range 0.9 to 3.3). A complete or constant-rising pressure stricture was defined if the contrast medium did not pass with a pressure of up to 40 cm H2O or a constant rise in pressure was apparent at a flow of 10 mL/min in the pressure-flow study (modified Whitaker-test).16 All the strictures were able to be passed with a 0.035-inch guidewire in an antegrade fashion. Under fluoroscopic control, the guidewire was pushed through the stenosis. If this was not possible, the nephrostomy tube was changed to a 5F ureteral catheter, which was inserted until above the stricture and the guidewire bypassed the stenosis. The end of the guidewire was extracted cystoscopically from the intestinal urinary pouch with a grasp. A flexible, wire-mounted cold-knife (Fa. Olympus, Hamburg, Germany) was pulled under fluoroscopic control through the UAS in retrograde fashion, and the stenosis was incised circularly three to six times. The strictured areas were stented with a polyurethane stent (8 to 12F) for 6 to 12 weeks. Broad-spectrum antibiotics (as prophylaxis)12 or the appropriate antibiotics (according to the antibiogram on the base of the urine cultures) were given routinely perioperatively. Urine cultures were performed monthly. Asymptomatic urinary infections were treated with a short-course of antibiotics. The follow-up consisted of diuretic (20 mg furosemide at a 20-minute sequence time) renal scintigraphy at 3 months, annually for the first 2 years, and biannually thereafter. Renal ultrasonography was performed at 3-month intervals for the first 2 years and twice yearly thereafter. If necessary, diuretic renography and/or computed tomography were performed. Success was defined as scintigraphic, radiographic, and sonographic resolution of obstruction and symptomatic relief. Possible prognostic factors predicting outcome were evaluated using the chi-square test for categoric variables and the Student t or Wilcoxon rank sum test for continuous data. Logistic regression analysis was applied to determine the predictors of incision success. For the construction of KaplanMeier recurrent-free interval curves, the time from the last scintigraphic follow-up in successfully treated patients and the time to failure was considered the censor point and endpoint, respectively. Using a Cox proportional hazard model, multiple variables were simultaneously evaluated to determine the role of multiple independently associated factors in UROLOGY 61 (3), 2003

FIGURE 1. Kaplan-Meier curve showing success rate of CNI for UASs in group 1 (primary treatment) and group 2 (secondary CNI after failure of primary CNI).

the outcome of endoureterotomy. A P ⱕ0.05 was considered statistically significant.

RESULTS CNI of the UAS was performed in all patients without any serious complications. Perioperatively, minimal extravasation was documented in 14 cases. However, postoperatively, no urinoma was diagnosed by antegrade pyelography and sonographic control. No immediate perioperative urinary tract infections were noted. The operation time averaged 26 minutes (range 12 to 41) for unilateral strictures and 48 minutes (range 30 to 71) for bilateral strictures. The average hospital stay was 3.6 days (range 2 to 8). To reduce the hospital stay, the preoperative examinations, placement of the nephrostomy tube, and Whitaker test were performed on an outpatient basis for the last 5 cases. Consecutively, the hospital stay was reduced by 1.4 days (range 1 to 2). In group 1, the overall success rate was 60.5% (26 of 43) at a mean follow-up of 38.8 months (range 12 to 85) after primary CNI. The success rate at 1, 2, and 3 years was 86%, 67.8%, and 60.5%, respectively. In the first year (at 6, 9, 11, 11, 12, and 12 months), 6 failures occurred; in the second year (at 14, 14, 15, 15, 16, 16, 18, and 23 months) 8, and in the third year (at 25, 27, and 28 months) 3 occurred. No failure was detected after 28 months, and 26 patients were at risk beyond 28 months (Fig. 1). Of the 17 failed primarily endourologically treated UASs, a secondary CNI was performed in 7. In 4 patients, the stent was left in place and changed on an outpatient basis every 3 to 6 months. The reason for this approach was the refusal of 1 patient to open surgery and the high operative risk in the other 3 patients. The remain513

months or longer, stricture length 1.5 cm or less, and hydronephrosis grade I-II) resulted in a success rate of 100%. On the other hand, in no patient (n ⫽ 6) with the presence of all of the unfavorable factors (interval to stricture formation less than 12 months, stricture length greater than 1.5 cm, and hydronephrosis grade III-IV) was primary CNI successful. Using Cox proportional model to evaluate the factors listed in Tables I and II for their association with the success of CNI for UAS, no factor was found to be significantly and independently associated with outcome. COMMENT

FIGURE 2. Algorithm showing outcome of CNI in our patients (n ⫽ 40) with UASs (n ⫽ 43).

ing 6 patients underwent successful surgical revision (Fig. 2). In group 2 (n ⫽ 6 patients), restenosis occurred at 4.6 months (range 1 to 9) after the second intervention (Fig. 1). In 2 patients, nephrectomy was performed because of fulminating urosepsis 4 and 6 months after the second incision. Three cases with relatively long, complete UASs were stented permanently after a second failed incision. Two patients were treated successfully with surgical revision (Fig. 2). The outcomes were examined using univariate statistical analysis (Tables I and II). The type and length of the stricture, kidney function, hydronephrosis grade, presence of urinary infection at presentation, radiotherapy, number of incisions, and premature appearance of the anastomosis stricture influenced the outcome of CNI in a statistically significant manner (P ⬍.05). In contrast, patient sex and age, side of the UAS, extravasation, antibiotic duration (applied only perioperatively or after patient discharge), type of ureter implantation, and stent width and duration seemed to be independent of the outcome of CNI (P ⬎.05). Logistic regression analysis of all the factors that were significant with univariate analysis revealed the interval to stricture formation to be the most significant, with a higher adjusted odds ratio of 2.45, followed by stricture length (adjusted odds ratio 2.04) and hydronephrosis grade (adjusted odds ratio 1.79). The presence of two or more of the most favorable or two or more of the most unfavorable factors had a more significant impact on the outcome than any individual factor. Selecting only the patients (n ⫽ 8) with the most favorable factors (interval to stricture formation 12 514

In published reports, experience with CNI for UAS is limited. Despite the good results of CNI (success rate 80% to 100%) in patients with benign ureteral stenoses,17 this method has been applied sporadically in cases of UAS.3,18 In an animal model, different methods of endoureterotomy have been evaluated. It was found that electroincision was as effective as CNI. Incision of any type (electrosurgical or cold) seems to be more effective than balloon dilation.19 Encouraged by our past preliminary experience12 with CNI for UASs, we used this method as the initial treatment in any patient presenting with a nonmalignant UAS. In cases of primary treatment, our long-term result of 60.5% at a mean follow-up of 39 months is to date satisfactory, because no severe complications have been observed, and it is comparable with those of former series.3,9,20 –22 Furthermore, by avoiding complicated endoscopic devices, as well as miniaturized cutting electrodes, our method becomes simpler and faster compared with the series of other investigators.5,9 In the case of laser incision, a percutaneous antegrade approach through the upper or mid-calix was used and the tract was dilated to 30F using Amplatz or balloon dilators, making that method more invasive and time consuming.22 Our multifactorial analysis confirmed that the interval to stricture formation together with stricture length and hydronephrosis grade at presentation were the most significant factors for the prognosis of outcome. Our analysis showed that the shorter the period to the appearance of UAS after urinary diversion, the poorer the prognosis after endourologic treatment. We believe the premature appearance of the UAS is due to a severe surgicaltechnical mistake with extensive ischemic damage of the ureteroenteric area that cannot be managed endourologically. The type of stricture was also found to affect the outcome, with partial strictures responding more favorably than complete ones. The side (left/right) and type of ureteral implantaUROLOGY 61 (3), 2003

TABLE I. Statistical analysis of categorical variables in success of cold-knife incision in group 1* Variable Sex Female Male Side Right Left Irradiation Yes No Kidney function ⬎25% ⬍25% Hydronephrosis grade I–II III–IV Stricture type Complete Partial Urinary infection at presentation Yes No Type of ureter implantation Refluxive Antirefluxive Antibiotic duration Perioperatively After discharge Extravasation during cold-knife incision Yes No

Success (n)

Failure (n)

9 (37) 17 (63)

6 (35) 11 (65)

0.964

0.971 (0.269–3.496)

9 (37) 17 (63)

7 (41) 10 (59)

0.189

1.322 (0.375–4.658)

1 (4) 25 (96)

5 (42) 12 (58)

0.018

0.096 (0.010–0.915)

25 (96) 1 (4)

8 (47) 9 (53)

⬍0.001

28.125 (3.073–257.426)

25 (96) 1 (4)

6 (35) 11 (65)

⬍0.001

45.833 (4.915–427.361)

7 (27) 19 (73)

14 (82) 3 (18)

⬍0.001

0.079 (0.017–0.360)

8 (31) 18 (69)

11 (65) 6 (25)

0.028

0.242 (0.066–0.887)

20 (77) 6 (23)

14 (82) 3 (18)

0.669

0.714 (0.152–3.349)

6 (23) 20 (77)

7 (41) 10 (59)

0.206

0.429 (0.114–1.618)

8 (31) 18 (69)

6 (23) 11 (77)

0.757

0.815 (0.223–2.982)

P Value

Odds Ratio (95% CI)

Data presented as the number of patients, with the percentage in parentheses unless otherwise noted. * Pearson chi-square test.

TABLE II. Statistical analysis of continuous variables in success of cold-knife incision in group 1 Variable Age (yr) Stricture length (cm) Interval to stricture formation (mo) Incisions (n) Stent width (F) Stent duration (wk)

Total 67.68 1.71 18.63 3.63 8.65 7.81

(5.16) (0.67) (13.58) (1.61) (1.29) (1.56)

Success 68.12 1.33 26.19 4.23 8.58 7.54

(4.99) (0.42) (12.47) (1.07) (1.30) (1.03)

Failure 66.93 2.29 7.06 2.71 8.76 8.24

(5.51) (0.53) (2.33) (0.47) (1.31) (2.11)

P Value 0.948* ⬍0.001† ⬍0.001† 0.001† 0.275† 0.424†

Data presented as the mean, with the standard deviation in parentheses. * Student’s t test. † Wilcoxon rank sum test.

tion (reflexive/nonrefluxive) were not found to influence the outcome. Other investigators23 found similar long-term success rates in both crossed and uncrossed ureters. However, Wolf et al.20 found statistically significant worse rates in the left UAS after endourologic treatment. Regarding postincision stenting, we found that stent duration (range 6 to 12 weeks) and stent diameter (range 8 to 12F) had no beneficial effects on UROLOGY 61 (3), 2003

the outcome. Kramolowky et al.4 and Shapiro et al.8 described a disappointing patency rate (20% and 16%, respectively) using balloon dilation, with an average stenting duration of the ureter of only 2 weeks. We stent for 6 to 8 weeks, which is a widely accepted practice in published studies.12 In contrast, Ravery et al.21 postulated that the increased duration of ureter stenting may have promoted healing of the ureter and attributed the high suc515

cess rate of 61% to the very long duration of stenting (4 to 30 months). However, in a recently investigated animal model, no direct association has been found between stent duration and outcome after endoureterotomy.24 Similarly, Wolf et al.20 proved statistically that the stenting duration (4 weeks or less versus greater than 4 weeks) did not influence the short and long-term success rate of the endoureterotomy, not only in cases of benign ureter stricture but also in cases of ureteroenteric stricture. The importance of renal function and the hydronephrosis grade of the ipsilateral kidney on the prognosis of CNI has been identified as well. Only one of the nine strictures in ureters subtending a kidney with less than 25% of total renal function and none of the strictures in ureters subtending a kidney with hydronephrosis greater than grade II were successfully treated. Lin et al.11 and Wolf et al.20 also showed that normal renal function or function greater than 25% is implicated with increased success of endoureterotomy. Although in other series,17,25 previous radiotherapy had no significant influence on the outcome, in our patient series, radiogenic damage of the ureterointestinal anastomosis predicted a negative outcome of CNI in a statistically significant manner. Because the secondary CNI achieved no success, the most important question would be the following: which therapy can be applied in cases of stricture recurrence after failed CNI? Despite the second endourologic treatment with balloon dilation recommended by some investigators, the longterm results of the multiple attempts were comparable with those of the first treatment.26,27 A combination of different methods (balloon dilation and incision) has been suggested21 as a possible alternative method. However, the long-term results are not significantly better.3,5,20 In our experience, the indication for open surgery must be retained for relatively young patients with no high operative risk, especially those patients with unfavorable factors (interval to stricture formation less than 12 months, stricture length greater than 1.5 cm, and hydronephrosis grade III-IV) in whom primary CNI has failed. CONCLUSIONS UASs seem to be the most difficult stenoses for endourologic therapy. The most effective treatment remains open revision, for which a success rate of 89% was reported.4 The CNI is successful in 60.5% of primarily treated patients at a follow-up of more than 3 years. However, this technique fails uniformly as secondary procedure. By avoiding the use of the flexible endoscope, this method is 516

simple and minimally time-consuming, with extremely low morbidity, because dilation of the transrenal tract is not needed. The most important factors predicting the outcome are the interval to stricture formation, stricture length, and hydronephrosis grade of the affected kidney. Thus, the selection of patients with the most favorable prognostic factors will lead to excellent results (patency rate 100%). Compared with open surgery, CNI appears to be one of the most appropriate initial approaches, because the 3-year results of the primary incision have been quite satisfactory, with shortened hospitalization and decreased morbidity. REFERENCES 1. Killeen KP, and Libertino JA: Management of bowel and urinary tract complication after urinary diversion. Urol Clin North Am 15: 183–194, 1988. 2. Shapiro SR, Lebowitz R, and Colodny AH: Fate of 90 children with ileal conduit urinary diversion a decade later: analysis of complications, pyelography, renal function and bacteriology. J Urol 114: 289 –295, 1975. 3. Bierkens AF, Oosterhof GON, Meuleman EJM, et al: Anterograde percutaneous treatment of ureterointestinal strictures following urinary diversion. Eur Urol 30: 363–368, 1996. 4. Kramolowky EV, Clayman RV, and Weyman PJ: Management of ureterointestinal anastomotic strictures: comparison of open surgical and endourological repair. J Urol 139: 1195–1198, 1988. 5. Meretyk S, Clayman RV, Kavoussi LR, et al: Endourological treatment of ureteroenteric anastomotic strictures: long-term followup. J Urol 145: 723–727, 1991. 6. Vandenbroucke F, Van Poppel H, Vandeursen H, et al: Surgical versus endoscopic treatment of non-malignant uretero-ileal anastomotic strictures. Br J Urol 71: 408 –412, 1993. 7. Rosen RJ, McLean GK, Freiman DB, et al: Obstructed ureteroileal conduits: antegrade catheter drainage. AJR Am J Roentgenol 135: 1201–1204, 1980. 8. Shapiro MJ, Banner MP, Amendola MA, et al: Balloon catheter dilation of ureteroenteric strictures: long-term results. Radiology 168: 385–387, 1988. 9. Cornud F, Lefebvre JF, Chre´ tien Y, et al: Percutaneous transrenal electro-incision of ureterointestinal anastomotic strictures: long-term results and comparison of fluoroscopic and endoscopic guidance. J Urol 155: 1575–1578, 1996. 10. Gerber GS, Kuznetzov D, Leef JA, et al: Holmium: YAG laser endoureterotomy in the treatment of ureteroenteric strictures following orthotopic urinary diversion. Tech Urol 5: 45–48, 1999. 11. Lin DW, Bush WH, and Mayo ME: Endourological treatment of ureteroenteric strictures: efficacy of Acucise endoureterotomy. J Urol 162: 696 –698, 1999. 12. Poulakis V, Witzsch U, de Vries R, et al: Antegrade percutaneous endoluminal treatment of non-malignant ureterointestinal anastomotic strictures following urinary diversion. Eur Urol 39: 308 –315, 2001. 13. McDougal WS: Use of intestinal segments in the urinary tract: basic principles, in Walsh PC, Retik AB, Stamey TA, et al (Eds): Campbell’s Urology. Philadelphia, WB Saunders, 1992, vol 3, pp 2595–2629. 14. Fisch M, and Hohenfellner R: Transversum-Conduit, in Hohenfellner R, Fichtner J, and Stein R (Eds): Ausgewa¨ hlte UROLOGY 61 (3), 2003

urologische OP-Techniken. Stuttgart, Thieme, 1997, pp 6.33– 6.48. 15. Abol Enein H, and Ghoneim M: Orthotope Ileumersatzblase mit Ureterimplatantion mittels sero¨ sem extramuralem Tunnel, in Hohenfellner R, Fichtner J, and Stein R (Eds) Ausgewa¨ hlte urologische OP-Techniken. Stuttgart, Thieme, 1997, pp 6.121– 6.127. 16. Whitaker RH: Methods of assessing obstruction in dilated ureters. Br J Urol 45: 15–22, 1973. 17. Goldfischer ER, and Gerber GS: Endoscopic management of ureteral strictures. J Urol 157: 770 –775, 1997. 18. Schneider AW, Conrad S, Busch R, et al: The cold-knife technique for endourological management of stenoses in the upper urinary tract. J Urol 146: 961–965, 1991. 19. Figenshau RS, Stone AM, Clayman RV, et al: Endoureterotomy in an animal model: comparison of electrosurgical, mechanical and balloon treatment modalities. J Urol 147(suppl): 470, 1992. 20. Wolf JS, Elashry OM, and Clayman RV: Long-term results of endoureterotomy for benign ureteral and ureteroenteric strictures. J Urol 158: 759 –764, 1997. 21. Ravery V, de la Taille A, Hoffmann P, et al: Balloon catheter dilatation in the treatment of ureteral and ureteroenteric stricture. J Endourol 12: 335–340, 1998. 22. Watterson JD, Sofer M, Nott L, et al: Holmium: YAG laser endoureterotomy for ureterointestinal strictures. J Urol 167: 1692–1695, 2002. 23. Banner MP, Pollack HM, Ring HW, et al: Catheter dilatation of benign ureteral strictures. Radiology 147: 427–433, 1983. 24. Kerbl K, Chandhoke PS, Fingenshau RS, et al: Effect of stent duration on ureteral healing following endoureterotomy in an animal model. J Urol 150: 1302–1305, 1993. 25. Beckmann CF, Roth RA, and Bihrle W: Dilatation of benign ureteral strictures. Radiology 172: 437–441, 1989. 26. Glanz S, Gordon DH, Butt K, et al: Percutaneous transrenal balloon dilatation of the ureter. Radiology 149: 101–104, 1983. 27. Kwak S, Leef JA, and Rosenblum JD: Percutaneous balloon catheter dilatation of benign ureteral strictures: effect of multiple dilatation procedures on long-term patency. AJR Am J Roentgenol 165: 97–100, 1995. EDITORIAL COMMENT The reported success rate for minimally invasive treatment of ureteroenteric strictures varies considerably, from 16% to 75%. In this report, the authors describe a success rate of 86%, 68%, and 61%, respectively at 1, 2, and 3 years. This is somewhat better than most series. There are several possible explanations for this. The authors’ technique is notable for the use of a cold-knife, which may minimize thermal damage to the surrounding tissue. In addition, the authors used multiple shallow cuts rather than a single deep incision. Indeed, they found that the number of cuts was a significant factor in their success; a mean of 4.23 incisions was made in successful cases, and the mean in failed cases was only 2.71 (P ⫽ 0.001). A related finding was that the presence of extravasation after the incisions, noted in

UROLOGY 61 (3), 2003

31% of successful cases and 23% of failed ones, was not associated with outcome. It is generally theorized that endoscopic incision of ureteral strictures is effective when an incision through the entire depth of scar induces entry of healthy cells to regenerate a portion of the ureteral wall. This report suggests that, at least for ureteroenteric strictures, the mechanism may be different. Rather than converting the circumferential scar at the stricture site to a partial scar that contains a portion of healthier ureteral wall (which would be expected with the theory of ureteral regeneration), a successful outcome may simply represent widening of the scar’s lumen. Another factor in the authors’ high success rate may be their patient population. Several prognostic factors for success were evaluated. Using logistic regression analysis, the authors concluded that the degree of hydronephrosis, length of stricture, and interval from urinary diversion to stricture formation were the most important factors. In univariate analysis, the authors also found associations with renal function, completeness of the stricture (“complete” versus “partial”), a history of radiation treatment, and urinary tract infection. The interval to stricture formation, a history of radiation treatment, and urinary tract infection have not consistently been associated with outcome in other reports. Conversely, poor renal function (this probably represents the same phenomena as hydronephrosis and is more objectively measurable), long strictures (greater than 1 to 2 cm depending on the report), and complete or very tight strictures have been associated with poor treatment outcome in most studies. In this series, 23% of patients had differential renal function of less than 25%; the strictures reported in 48% to be “complete” actually were not “complete,” because the authors reported being able to pass a guidewire in all cases; and the average stricture length was 1.7 cm. Inasmuch as these factors may differ from the patients in other reports, this may explain a portion of the authors’ overall results. There are two important take-home messages from this report. First, CNI with multiple small cuts without extravasation, as opposed to a single “hot” incision through the entire scar depth, may be a better way to manage ureteroenteric strictures. Second, the authors did not find that any single one factor was of overwhelming significance in predicting the outcome of minimally invasive management of ureteroenteric strictures, but did note that the major factors are cumulative in their predictive ability. Taken together with other published reports on the subject, I think that the three most important factors in the minimally invasive management of ureteroenteric strictures probably are renal function, stricture length, and completeness of the stricture. J. Stuart Wolf, Jr., M.D. University of Michigan Medical Center Section of Urology Ann Arbor, Michigan doi:10.1016/S0090-4295(02)02504-9 © 2003, ELSEVIER SCIENCE INC. ALL RIGHTS RESERVED

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