0022-534 7/92/1483-0775$03.00/0 THE JOURNAL OF UROLOGY Copyright© 1992 by AMERICAN UROLOGICAL ASSOCIATION, INC.
Vol. 148, 775-783, September 1992
Printed in U.S.A.
Original Articles ENDOPYELOTOMY: COMPARISON OF URETEROSCOPIC RETROGRADE AND ANTEGRADE PERCUTANEOUS TECHNIQUES IRIT MERETYK, SHIMON MERETYK
RALPH V. CLAYMAN
From the Division of Urology and Department of Radiology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri
To date 2 approaches have been developed for performing endopyelotomy, that is the antegrade and retrograde approaches. Experience with antegrade transnephrostomy endopyelotomy is quite large and the results have been excellent. However, the need for percutaneous nephrostomy and prolonged hospitalization have been 2 drawbacks to this approach. In contrast, experience with retrograde transureteral endopyelotomy is scant. However, a ureteroscopic approach is attractive from the standpoint of eliminating the need for a large nephrostomy tube and because of the possibility of performing this procedure on an outpatient basis or during a short hospital stay. We report our experience with antegrade and retrograde endopyelotomy in 41 patients. The hospital stay (3.4 versus 4.0 days), nephrostomy tube size (8F to lOF versus 20F to 22F) and nephrostomy tube duration (2.9 versus 3.8 days) were all less with the retrograde approach. The initial success rate was similar between the 2 methods: 79% (retrograde) versus 78% (antegrade). However, the analgesic requirements (5.3 versus 3.5 doses) and the occurrence of significant complications (that is late uteteral stricture in 20%) were greater with the ureteroscopic approach. With the methods currently available, we believe that antegrade endopyelotomy is the preferred approach for endopyelotomy. KEY WORDS:
kidney calculi, endoscopy
The endourological approach to ureteropelvic junction obstruction is based upon the concept of the intubated ureterotomy, originally described in 1903 by Albarran,1 and later popularized by Davis. 2 •3 In 1983 Wickham reported the first series of pyelolysis, in which the obstructed ureteropelvic junction was approached via a nephrostomy tract using a direct vision cold knife urethrotome. 3 Later, Smith popularized this procedure in the United States and others soon began to report on endopyelotomy. The success rate with antegrade endopyelotomy ranges from 72 to 88% for congenital and acquired ureteropelvic junction obstruction, a figure comparable to open pyeloplasty results. 4- 6 Paralleling the developments with endopyelotomy were developments in ureteroscopy. The first ureteronephroscopic endopyelotomy was reported in 1986. This method has been developed further by Thomas and us. The immediate benefits of this approach are its less invasive nature and the elimination of the 4 to 6 weeks of postoperative nephrostomy tube drainage,7, 8 Early reports indicated a success rate equivalent to the antegrade approach. At our university antegrade and retrograde methods have been used to incise the obstructed ureteropelvic junction. We report our experience with 41 patients, comparing these 2 methods with regard to immediate operative and hospital information, and long-term followup (9 to 12 months). MATERIALS AND METHODS
Between November 1984 and September 1989, 17 men and 24 women with 42 ureteropelvic junction obstructions (1 patient
had bilateral obstruction) were entered into the study. There were 23 antegrade procedures (11 on the right and 12 on the left sides) and 19 retrograde procedures (12 on the right and 7 on the left sides) in patients ranging from 18 to 87 years old (mean age 49.8). The 42 cases of ureteropelvic junction obstruction were primary in 28 (12 antegrade and 16 retrograde procedures) and secondary in 14 (11 antegrade and 3 retrograde procedures). The most common presenting symptoms were flank or abdominal pain in 33 patients (79%), infection in 11 (26%), stones in 10 (24%) and/or failed pyeloplasty in 6 (14%), while 1 (2%) had an abdominal mass. Table 1 presents the objective preoperative evaluation. All but 1 of our patients had undergone at least 2 radiographic examinations. In this patient the excretory urogram (IVP) clearly demonstrated a ureteropelvic junction stricture. The 3 patients who had an apparently normal nephrostogram were subsequently diagnosed as having ureteropelvic junction obstruction: 1 by a positive retrograde ureterogram and renal scan, 1 by an IVP, retrograde ureterogram and renal scan, and 1 by a Whitaker test. The 4 patients with a normal renal scan were diagnosed as having ureteropelTABLE 1.
Endopyelotomy: objective preoperative evaluation Objective Preoperative Evaluation*
Obstructed Equivocal Normal Totals
19 3 3
16 4 4
Retrograde Renal Nephrostogram U re t erogram Scan
* All but 1 patient had 1 or more diagnostic studies.
Accepted for publication January 10, 1992. 775
Whitaker Test (cm. water) 10 (more than 20) 13 (15-20) 6 (less than 15) 29
MERETYK, MERETYK AND CLAYMAN
vie junction obstruction by an IVP (2), nephrostogram (2) and/ or Whitaker test (2). Of these patients 1 had undergone the renal scan with an internal stent to assess the functional, not obstructive, status of the kidney. The 6 patients with normal values on the Whitaker test (that is less than 15 cm. water) were diagnosed as having ureteropelvic junction obstruction by means of an IVP (3), nephrostogram (6), retrograde ureterogram (2) and/or renal scan (4). In 1 patient with a normal Whitaker test and a normal nephrostogram, a trial of upper tract decompression with a ureteral stent was initiated. During a 4-week period, with the stent in place, the patient had no further discomfort and, therefore, diagnosis was intermittent ureteropelvic junction obstruction. She subsequently underwent endopyelotomy. -ln l-Q pati-ents-undeI"going antegrade endopyelotomy a concomitant renal calculus was removed. In these patients either the calculus was remote from the ureteropelvic junction or the surgeon believed that the ureteropelvic junction obstruction was more than inflammatory in nature and, thus, required endopyelotomy. Presently, to document ureteropelvic junction obstruction better, these patients are discharged from the hospital after stone removal with the nephrostomy tube still in place. A week later a Whitaker test is performed to evaluate the functional patency of the ureteropelvic junction. In no patient undergoing retrograde endopyelotomy was a stone present at the time of the procedure. Techniques. Retrograde Endopyelotomy: The patient is placed on the urology fluoroscopy table in a modified dorsal lithotomy position. In most patients a small (8F) nephrostomy tube is left in place after the preoperative Whitaker test, which allows for continuous drainage of irrigant fluid during the procedure. A 0.035-inch Bentson floppy tip guide wire or 0.035inch Terumo glide wire is advanced up the ureter via a flexible cystoscope and coiled in the renal pelvis. If the ureteropelvic junction cannot be traversed, then an endopyelotomy is contraindicated. A 7F ureteral dilating balloon (8 cm. long and 6 mm. in diameter) is advanced over the guide wire and positioned so that it traverses the distal ureter from the ureteral orifice to a point just above the ureterovesical junction. The balloon is inflated slowly (0.5 cc per minute) under fluoroscopic control and left fully inflated for 2 to 10 minutes. Upon deflating and removing the balloon, a 5F angiographic catheter is passed over the guide wire and into the renal pelvis, and both are fixed to the ureteral meatus with a single 2-zero silk suture. A long rigid ureteronephroscope (12F) or flexible deflectable ureteroscope (9.8F or 10.8F) is passed. Usually, in women a rigid ureteroscope can be used, whereas in men a flexible endoscope is necessary. When the flexible ureteroscope is used a 14F ureteral access sheath may be necessary to stabilize passage of the endoscope across the distal ureter. The ureteroscope is advanced alongside the 5F angiographic catheter up to the point of ureteropelvic junction obstruction. At this point the irrigant is changed from normal saline to sorbitol. A 2F, 3F or 5F angled tip Greenwald electrode with cutting current (50 to 100 watts) is used to make the incision. The 2F or 3F electrodes with a 250 µ. tip are preferred. The ureteropelvic junction is incised along its posterolateral border until the periureteral fat is seen, and then extended proximally 1 cm. into the renal pelvis. A nephrostogram is performed. Marked extravasation at the ureteropelvic junction should be present, which indicates that the depth of the endopyelotomy incision was sufficient. A 260 cm. long, 0.035-inch exchange guide wire is passed via the 8F nephrostomy tube and grasped with a 3F grasping forceps passed through the ureteroscope. The exchange guide wire is pulled caudal and delivered out the urethra, thereby establishing a through-and-through guide wire. The 5F angiographic catheter and the guide wire are removed. Then, an 8 mm., 4 cm. long, ureteral dilating balloon is passed over the exchange guide wire and placed across the incised ureteropelvic
junction. Inflation of the balloon to 1 to 2 atmospheres separates the cut edges of the ureteropelvic junction and enables the surgeon to identify any inadequately incised areas. The balloon catheter is removed and, using 2 metal tip pushers, a 7F /14F internal stent is advanced over the exchange guide wire so that the 14F portion of the stent overlies the incised ureteropelvic junction. A urethral catheter is placed at the end of the procedure. On postoperative morning 2 a nephrostogram is performed. If there is no extravasation the nephrostomy tube can be removed under fluoroscopic control. Likewise, the urethral catheter is removed. The patient is discharged from the hospital the same day or the next morning with the internal 7F/14F stent in place. On an outpatient basis 6 weeks later cystoscopy is performed and the stent is removed withthe patientunder intravenous sedation. The patency of the ureteropelvic junction is assessed at the same time by passing the flexible ureteroscope or performing retrograde ureterography. At 3 weeks and 3 months after the endopyelotomy procedure a furosemide washout renal scan is obtained. At 6 months and at 1 year a nuclear renal scan or an IVP is obtained. If there is any evidence of obstruction a Whitaker test is performed.7· 8 Antegrade Endopyelotomy: The patient is placed on the urology/fluoroscopy table in the prone position. 9•1° Flexible cystoscopy is performed and a 0.035-inch Bentson floppy tip guide wire or Terumo glide wire is advanced up the ureter and coiled in the renal pelvis. If the ureteropelvic junction cannot be cannulated, antegrade endopyelotomy as described is contraindicated. Antegrade percutaneous access through a posterior upper calix or posterior middle calix is obtained, resulting in a straight path to the ureter. A 5F angiographic catheter or 6 mm. ureteral dilating balloon is placed over the initial retrograde guide wire and likewise advanced into the renal pelvis. If a balloon is used, it is positioned such that the balloon straddles the ureteropelvic junction. The balloon is inflated with contrast medium to 1 atmosphere, thereby outlining the area of the ureteropelvic junction narrowing. The ureteropelvic junction is approached alongside the 5F catheter or inflated balloon using a urethrotome, insulated rigid nephroscope or, rarely, a flexible nephroscope. With the cold straight knife, or angled tip 2F, 3F or 5F Greenwald electrode with cutting current (50 to 100 watts), the ureteropelvic junction is incised posterolaterally until periureteral fat is seen. The 2F and 3F electrodes are preferred. The incision is ex tended distally for 1 cm. into healthy and normal caliber ureter along the posterolateral aspect of the ureteropelvic junction. After the incision, a 260 cm. exchange guide wire is passed via the balloon catheter and retrieved by the nephroscope. This establishes a through-and-through guide wire. Then a nephrostogram is obtained. Marked extravasation indicates sufficient depth of the incision. If there is a question as to the adequacy of the incision an 8 mm. ureteral dilating catheter may be advanced over the exchange guide wire until it straddles the ureteropelvic junction. The balloon is inflated to 1 to 2 atmospheres, thereby separating the cut edges of the ureteropelvic junction and identifying any inadequately incised areas. If there is a waist in the balloon, a deeper incision in the ureteropelvic junction is made. An internal 7F/14F stent then is advanced over the exchange guide wire using 2 metal tip pushers (1 placed cephalad and 1 placed caudal, thereby trapping the stent between the 2 pushers) until the 14F portion overlies the ureteropelvic junction. A coil of the stent is formed in the renal pelvis and bladder, respectively. A 20F to 22F Councill catheter serves as a nephrostomy tube and a Foley catheter is placed in the bladder. On postoperative morning 2 a nephrostogram is obtained. Provided there is no extravasation the nephrostomy tube (under fluoroscopic control) and the urethral catheter are removed. The 7F /14F stent is left indwelling for 6 weeks. At 6 weeks the
ENDOPYELOTOMY: COMPARISON OF TECHNIQUES
stent is removed cystoscopically on an outpatient basis. At the same session, flexible ureteroscopy or a retrograde ureterogram is done to assess the patency of the ureteropelvic junction. Followup studies include a renal scan and/or IVP at 3, 6 and 12 months. If there is a question of recurrent obstruction a Whitaker test is performed. RESULTS
Between November 1984 and September 1989, 41 patients with 42 ureteropelvic junction obstructions were entered into the study. One patient had bilateral ureteropelvic junction stricture. A total of 23 patients (11 men and 12 women) underwent antegrade endopyelotomy, while 19 (6 men and 13 women) underwent retrograde endopyelotomy. In the antegrade group 12 patients had primary and 11 had secondary ureteropelvic junction obstruction, compared to 16 and 3, respectively, in the retrograde group. Patient age ranged from 18 to 87 years (mean 49.8). The most frequent presenting symptoms were flank or abdominal pain of varying duration and severity (79%). In 1 patient the condition was incidentally diagnosed (that is negative objective studies but relief of intermittent flank pain by placement of an indwelling ureteral stent). An IVP and a Whitaker test were the most frequent preoperative examinations (table 1). The average procedural time for antegrade and retrograde endopyelotomy was 200 minutes and 179 minutes, respectively (table 2). In half of the patients an additional procedure was performed at endopyelotomy (that is a Whitaker test or stone removal) and this served to increase the average procedural time. While all patients undergoing a retrograde approach required ureteral dilation, none in the antegrade group underwent ureteral dilation. In half of the retrograde group a ureteral access sheath was inserted. All antegrade group patients had a 20 to 22F nephrostomy tube placed, while 15 (79%) in the retrograde group had 8 to lOF nephrostomy tubes. Nephrostomy duration averaged 3.8 days in the antegrade group and 2.9 days in the retrograde group. Generally, blood loss was minimal in both groups, averaging 1.4 gm. % hemoglobin decrease in the antegrade procedures and 1.8 gm. % hemoglobin decrease in the retrograde group. A total of 4 patients required blood transfusions: 2 with antegrade TABLE 2.
and 3 with retrograde endopyelotomy. Five units of packed cells were given for 3 procedures in the retrograde group, while 2 units were given for 2 procedures in the antegrade group. However, 1 of these patients was the individual who underwent bilateral endopyelotomy (1 side via the antegrade approach and 1 side via the retrograde approach). One patient in the antegrade group had delayed severe bleeding due to a renal arteriovenous fistula and he was given an additional 8 units of blood elsewhere and 2 units of blood at our hospital before segmental renal artery embolization (table 3). None of the patients had fever higher than 37.8C during the hospital stay. However, 1 patient in the antegrade group had sepsis while at home 10 days after endopyelotomy, which required rehospitalization and antibiotic therapy. Analgesic requirements were similar in the 2 groups, averaging 3.5 doses of parenteral analgesics in the antegrade group and 5.3 doses in the retrograde group. Interestingly, the smaller size of the nephrostomy tube in the retrograde group did not appear to lessen patient discomfort. In the antegrade group 1 patient did not require any analgesics and 2 were managed with oral analgesics alone. In the retrograde group 1 patient was managed on oral analgesics alone. Hospital stay was brief in both groups, averaging 4 days in the antegrade group and 3.4 days in the retrograde group. An indwelling ureteral stent, usually 7F/14F, was placed in all 42 ureters. Stent duration averaged 6.5 weeks with the antegrade procedure and 6 weeks with the retrograde procedure. The complications following endopyelotomy are summarized in table 3. The most threatening complication was bleeding, which occurred in 4 patients (1 of whom underwent bilateral simultaneous endopyelotomy). Two patients in the retrograde group had a large perirenal hematoma. Interestingly, 1 patient in the retrograde group and 2 in the antegrade group had hemoglobin decreases of more than 3 gm. %, requiring transfusions but without proved perirenal hematomas. One patient with an acute hemorrhage underwent bilateral procedures. Therefore, there are 4 patients with a complication secondary to endopyelotomy after 5 procedures (3 retrograde and 2 antegrade procedures). Of the patients with an acute hemorrhage in the antegrade group 1 later had severe hematuria with passage of blood clots 2 weeks after endopyelotomy, which was
Endopyelotomy: procedural information Antegrade
Av. mins. procedural time (range) Cutting element(%) Endoscope used:* Rigid Flexible
SF, 5F and 7F Greenwald (83), cold knife (39), Collings' knife (30)
2F, SF and 5F Greenwald electrode (100)
26F Storz pyelotome or 20F urethrotome or 20F cystoscope (74) 20-24F rigid and 15-18F flexible nephroscope (9)
12F short rigid ureteroscope, 10.8F flexible ureteroscope Olympus (42) llF flexible ureteroscope Storz, 9.8F flexible ureteroscope ACMI (42) (16) Yes, 6 mm. balloon with or without 14F ureteral access sheath Yes (15/19)
Both Ureter dilated
Nephrostomy (No. pts./ total) Nephrostomy size
Nephrostomy durationt Stent size (F) Stent duration (wks.) Av. gm.% hemoglobin change (range) Av. postop. analgesia doses (range) Av. days hospital stay (range)
3.8 (1-7) 7/14 6.5 -1.4 (0.2,-3.2)
8-lOF biliary urinary drainage catheter 2.9 (0-14) 7/14 6
* Numbers in parentheses refer to percentage of patients in whom this particular modality was used. t Does not include 2 outliers in antegrade (30 and 37 days) and 2 outliers in retrograde (14 and 90 days) groups in whom complications resulted in prolonged nephrostomy tube drainage.
MERETYK, MERETYK AND CLAYMAN TABLE 3.
Antegrade Retrograde Endopyelotomy (%) Endopyelotomy (%) Major complications: Immediate: Blood loss requiring transfusion (3 gm. % or greater decrease in hemoglobin) Pulmonary edema/ascites Delayed: Arteriovenous fistula Sepsis U reteral stricture Overall Minor complications: Immediate: Urinoma Disp!aced--nephrostomy Pleural effusion Delayed: Stent related Overall
4. Endopyelotomy: subjective and objective results
Postop. mos. (range) Improved No change or worse
4 4 0
0 11 0
Overall failure rate is 17%, including 1 patient who required 2 endopyelotomies to achieve satisfactory outcome. * One patient had bilateral simultaneous antegrade and retrograde endopyelotomy. Therefore, this patient was not included in overall major complications under antegrade or retrograde. t Migration in 1 patient, occlusion in 2 and calcified in 2. t Migration in 2 patients and occlusion in 1.
secondary to a renal arteriovenous fistula. He was given 10 units of blood and underwent successful embolization. An elderly woman had bilateral ureteropelvic obstruction, and was treated simultaneously with right antegrade and left retrograde endopyelotomy. Congestive heart failure and oliguria developed in the immediate postoperative period requiring a 3-day stay in the intensive care unit_ A patient in the antegrade group had a large peripelvic urinoma that resolved with reinsertion of the percutaneous nephrostomy tube. . Early in our experience and on subsequent rare occasions, we placed a standard 7F stent following endopyelotomy (7 patients). However, in February 1987 we began to use a. 7F / 14F indwelling ureteral stent. These stents have a proximal and distal 7F pigtail. Half of the stent shaft is 14F without sideholes, while the other half of the stent shaft is 7F with multiple sideholes. The stent is positioned such that the 14F portion traverses the site of the endopyelotomy. Among the 6 small stents placed 2 problems occurred: 1) stent migration and 2) stent occlusion. Among 36 of the 7F/14F type stents placed, problems arose in 6 patients, including stent oc?lusi?n (2), discomfort requiring stent exchange (1), stent m1grat10n (1) and calcification of the stent (2). The last complication necessitated percutaneous ante grade removal of the stent in 1 patient and extracorporeal shock wave lithotripsy (ESWL *) of the stent in 1 patient before its removal. These are the only 2 instances of calcification of a 7F/14F stent that we have experienced and both occurred early in the development of this stent (August and September 1987). No other 7F/14F stents have calcified in our subsequent experience with placement of more than 80 of these stents since September 1987. Subjective followup averaged 22 months for the antegrade group and 17 months for the retrograde group. The success rates were 78% and 79%, respectively (table 4). All but 1 patient could be contacted by either telephone or mail. The patient who we could not contact was a known failure of endopyelotomy. Objective followup was obtained by an IVP and/or furosemide washout renal scan. A followup Whitaker test was performed in 11 patients: 8 in the retrograde group and 3 in the antegrade group. Objective followup averaged 9.5 months in the antegrade group and 12 months in the retrograde group. The success rate was 78% and 79%, respectively. Of 23 patients in the antegrade group 12 had primary ureteropelvic junction obstruction compared to 11 who were de* Dornier Medical Systems, Inc., Marietta, Georgia.
Whitaker Test (No.)
Antegrade endopyelotomy (23 pts.)*
22 (2-39) 78% 22%
9.5 (2-30) 78% 22%
Retrograde endopyelotomy (19 pts.Jt
Postop. mos. (range) Improved No change or worse
17 (4-36) 79% 21 %
12 (3-30) 79% 21 %
* Outcome results were secondary pyeloplasty in 2 patients (pate_llt; ureteropelvic3iinct10nT, seconclacy- endopyeiotomy in 1 (patent ureteropelvic junction), observation in 1 and unknown in 1. t Outcome results were secondary pyeloplasty in 1 patient (patent ureteropelvic junction), secondary endopyelotomy in 1 (patent ureteropelvic junction) and nephrectomy in 2.
fined as having secondary ureteropelvic junction obstruction (table 5). 5• 6 • 11- 14 The success rates were 75% and 91 %, respectively. In the retrograde group 16 of 19 patients had primary ureteropelvic junction obstruction and the success rate was 82%. All 3 patients with secondary ureteropelvic junction obstruction had an excellent outcome from retrograde endopyelotomy (table 5). Interestingly, the success rates are somewhat higher for secondary ureteropelvic junction obstruction in both groups. However, success even with primary ureteropelvic junction obstruction is routinely achieved in 75 to 81 % of the patients. Table 5 also compares our results with the results reported in the literature for surgical pyeloplasty and antegrade endopyelotomy procedures. Ureteral stricture was the most common complication among patients in the retrograde group. Of 20 patients 4 had strictures: 3 in the distal ureter and 1 in the mid ureter. Three strictures resolved with endoureterotomy, while in 1 patient balloon dilation failed. In the latter woman endoureterotomy also failed and nephrectomy was subsequently performed. No patient in the antegrade group had a ureteral stricture (table 6). Four patients in the retrograde group had recurrent stricture at the ureteropelvic junction within 2 to 4 months: 1 was cured by reincision of the ureteropelvic junction, 1 underwent a successful open operation and 2 underwent nephrectomy due to a nonfunctioning kidney. Five patients in the antegrade group had a recurrent stricture at the ureteropelvic junction: 1 was cured by reincision of the ureteropelvic junction, 2 underwent a successful open operation, 1 had a poorly functioning kidney but refused any additional treatment due to a lack of symptoms and 1 who failed endopyelotomy is the only patient in our series lost to followup. DISCUSSION
Ureteropelvic junction obstruction varies widely in its genesis and anatomy. Ureteropelvic junction obstruction may be congenital or acquired. Congenital causes include segmental dysfunction· intrinsic ureteral stricture; a ureteral kink, adhesions, bands o; valves; ureterovascular tangle, and obstructive high insertion. Acquired causes include post-inflammation, ischemic scarring or fixation; kinking due to ureterovesical reflux, and urothelial or extraureteral tumors. The age distribution of patients with ureteropelvic junction obstruction is relatively uniform from infancy through old age. The male-to-female ratio is 50:50. 15 The majority of affected adults have a long history of symptoms, including flank or back pain varying in severity and at times exacerbated by self-induced or iatrogenic diuresis. A history of urinary tract infection may accompany ureteropelvic junction obstruction and should always be considered when assessing patients with renal calculi. 16' 17 The evaluation of patients with suspected ureteropelvic junction obstruc-
ENDOPYELOTOMY: COMPARISON OF TECHNIQUES TABLE 5.
Therapy for ureteropeluic junction obstruction: review of the literature
Scardino and Scardino"
Ramsay et al6
Antegrade en- Cold knife dopyelotomy Antegrade en- Cold knife dopyelotomy Antegrade en- Cold knife dopyelotomy
Van Cangh et al'
Karlin and Smith, and Weiss et al 13
Kuenkel and Korth 14 Present study
Antegrade en- Cold knife dopyelotomy
Antegrade en- Electrocautery/cold dopyelotomy knife
Retrograde en- Electrocautery dopyelotomy
Initial Procedure: Ureteral Dilation
Success Rate (%) Primary Secondary Overall
Restricture (2.4), calculi (1.1), ? reoperation (2.2), secondary nephrectomy (3.0) Infection (?), technical prob18 !ems(?) Bleeding (5.1), hydrothorax 16 (7.7), stent migration (5.1) Hemorrhage (1.6), stent repo3-48 sitioning (?), ureteral stricture (3.1), ureteral avulsion (1.6) Pneumothorax (4.2), bleeding 12.4 (8), fever more than 38C (46) Bleeding (9) 22 (subjective), 9.5 (objective) Bleeding (16), ureteral stric- 17 (subjecture (21) tive), 12 (objective)
Hospital Stay (days)
6. Retrograde endopyelotomy: delayed distal ureteral strictures Type of Ureteroscope Used
U reteral Access Sheath
Stent Type (wks.)
U reterovesical junction Mid ureter
6 mm. balloon
8F-10F-12F semirigid dilators
8 mm. balloon
6 mm. balloon
tion should be sufficient to demonstrate the site and functional significance of the blockage. In most patients this requires an IVP plus 1 or more of the following studies: retrograde pyelography, renal isotope studies, nephrostogram and/or a Whitaker renal pelvic/bladder pressure study. 16· 18· 19 Obstruction producing functional impairment, troublesome symptoms, chronic infection or urolithiasis is an indication for treatment of ureteropelvic junction obstruction. 20 Since the initial operative repair of ureteropelvic junction obstruction by Trendelenburg in 1886, a variety of surgical procedures have been developed. These procedures can be classified into 4 categories: 1) advancement (Y-V plasty), 2) pelvic flap (Scardino or Culp procedure), 3) dismembered (AndersonHynes) pyeloplasty and 4) intubated ureterotomy. 11 • 21 Of these procedures the dismembered pyeloplasty is the most commonly performed. The overall success rate of these procedures is approximately 90%.11 Complications of surgical pyeloplasty include nephrectomy (3.2%), urinary fistula (2.6%) and recurrent ureteropelvic junction obstruction (2.4%). 2· 11 • 22-29 Repeat pyeloplasty is necessary in 2.2% of the patients.11 The basis for endopyelotomy harkens back to the description by Albarran in 1903 of a ureterotome externe, 1 which was subsequently popularized in the 1940s by Davis et al. 2· 30· 31 The procedure involves cutting from the outside of the ureter through the stenotic ureteropelvic junction or ureter and then placing a stent around which ureteral regeneration could progress. Studies on incised dog ureters have demonstrated that mucosa regenerates around the stent in 6 days, and the smooth muscle regenerates and regains peristaltic activity at 6 to 8 weeks. 30· 32 Interestingly, it was noted that regeneration of all layers of the ureter could be achieved even without an indwelling stent as long as adequate drainage was provided via a drain through the operative wound. 33-36 Clinically, the Davis intubated ureterotomy for treatment of ureteropelvic junction ob-
Ureterovesical junction Ureterovesical junction
Treatment (mos.) Endoureterotomy, patent (11) Endoureterotomy with triamcinolone injection, patent (14) Endoureterotomy, patent (20) Balloon dilation of stricture failed, endoureterotomy failed, nephrectomy
struction resulted in symptomatic relief in 85% of the patients and objective radiographically documented patency in 70% _11, 30, 31 In 1983 Wickham first reported percutaneous pyelolysis using a direct vision cold knife urethrotome passed via a nephrostomy tract. 3 This endoscopic modification of the Davis intubated ureterotomy avoided an open operation and left the ureteral blood supply intact. Subsequently, Badlani et al popularized this procedure (which they renamed endopyelotomy) as an acceptable alternative to open pyeloplasty in patients with either primary or secondary ureteropelvic junction obstruction. 4 Other urologists reported similarly favorable results (72 to 88% success rates). 5• 6· 22-29 These results were almost equivalent to an open procedure but the hospital stay and postoperative convalescence were markedly less with endopyelotomy compared to open procedures. 22 Our results with antegrade endopyelotomy are likewise in keeping with the reported literature (78% initial success with only 3.4 days of hospitalization). With the development of ureteroscopic instruments Bagley et al reported the first combined antegrade and retrograde approach to the obliterated ureteropelvic junction in 2 patients.37 However, the incision was performed through the nephrostomy tract and the ureteroscope served only for visual guidance. In 1986 Inglis and Tolley reported the first retrograde ureteroscopic endopyelotomy in 2 female patients using a rigid ureteroscope and a diathermy hook for incision. 38 The immediate benefits of the ureteroscopic approach seem to be its less invasive nature and the elimination of a long-term large nephrostomy tube. 7· 8· 38 Clayman et al also described incising the ureteropelvic junction from below the stricture; the advantage appeared to be that the starting point (narrowing in the ureter) and the ending point (capacious pelvis) of the endopyelotomy were more easily recognized. 7· 8
MERETYK, MERETYK AND CLAYMAN
In our series comparing the antegrade and retrograde endopyelotomy approaches there was no significant difference in operative time (200 versus 178.5 minutes). Overall, our average procedural time was longer than that reported by others (90 minutes). 5· 12• 22 However, in our series an additional procedure was performed in almost half of the endopyelotomy patients, including stone removal in 10, incision of a ureterocele in 1 and a Whitaker test in 19. Postoperative hemoglobin decrease, administration of parenteral analgesics and hospital stay were similar in the antegrade and retrograde groups. This finding is somewhat surprising bearing in mind that the retrograde approach is a less invasive procedure in which the need for a large bore 30F to 34F percutaneous nephrostomy tube is eliminated. Another interesting observation is that the 4 retrograde patients in whom no nephrostomy tube was placed still had the same analgesic requirement and same average hospital stay as the nephrostomy-bearing cohorts. The most serious complication was hemorrhage, which occurred in 10% of the patients and was similar in both groups. Four patients (3 with retrograde and 2 with antegrade endopyelotomy; 1 had bilateral simultaneous antegrade and retrograde endopyelotomy) had significant bleeding requiring a total of 7 units of blood. One patient in t he antegrade group had a renal arteriovenous fistula 2 weeks after the procedure and required an additional 10 units of transfusion followed by embolization. Among these 4 patients 3 had a primary ureteropelvic junction obstruction and 1 had a secondary ureteropelvic junction obstruction. Therefore, we could not attribute the bleeding to the problems associated with secondary obstruction due to possible anterior transposition of the anastomosis. T he question of whether bleeding is a preventable complication should be raised. On review of the operative reports of these patients, it becomes apparent that the usual safety guidelines, that is observation of the ureteropelvic junction for any arterial pulsation in the area of the planned incision and the incision itself being made at the posterolateral aspect of the renal pelvis, were strictly kept. Of the 4 patients 2 had a specific reason for the bleeding: incision into the parenchyma of t he kidney in 1 and incision possibly into an ovarian vein in 1 wit h a low lying kidney. We could find no other reason to account for the bleeding in the remaining 2 patients. It seems that bleeding, presumably from t he cut edge of the ureter or a posterior vein, may be an unpreventable complication even with a careful approach. 13• 39 None of t hese 4 patients required immediate operative intervention, and in all but 1 (arteriovenous fistula that was embolized angiographically) conservative treatment was sufficient. However, while performing endopyelotomy one should keep in mind this complication and be prepared for intervention al radiographic or operative intervention.13· 39 Parenthetically, an advantage of making the incision with an electrosurgical unit from an antegrade approach is the ability to identify endoscopically and point coagulate any smaller bleeding vessels. Complications related to drainage tubes (nephrostomies and stents) were also similar in both groups. Occluded or slipped stents and misplaced nephrostomy tubes were repositioned or exchanged under fluoroscopic guidance. In 2 patients the stent became severely calcified, and required antegrade removal in 1 and an ESWL treatment to fragment t he calcified deposits in 1. A total of 4 patients (21 %) in t he retrograde group had ureteral strictures (3 dista l and 1 mid ureter) within 12 months of the procedure (table 6 ), while none in the antegrade group experienced this late complication. Ureteroscopy is potentially a hazardous procedure. Various physicians report development of a post-ureteroscopy ureteral stricture of 3 to 5%.40-46 Late strictures may be attributed to extravasation of urine into periureteral tissues, infection or ischemia of t he ureteral wall. In our patients this problem could have been secondary to t he
duration of ureteroscopy (3 hours) or thermal damage from using electrocautery to incise the ureteropelvic junction.47· 48 We do not believe that any of the strictures were related to the stent, since the lower pigtail was always in the bladder. This impression is further corroborated by the observation that no patient in the antegrade endopyelotomy group had a ureteral stricture. Likewise, we do not believe that balloon dilation of the ureter to 6 mm. was a causative factor, since strictures secondary to balloon dilation are a rare occurrence. 49 Also, while of initial concern, we could not relate stricture occurrence to use of the ureteral access sheath. Indeed, in our series strictures developed equally among patients in whom the ureteral access sheath was and was not used. Long-term objective and subjective followup was obtained in 98% of our patients. One patient who failed the procedure could not be contacted for further followup. Clinical improvement or failure was confirmed radiographically or by diuretic renograms in 40 patients. In doubtful cases a Whitaker test was performed. The initial objective response rate was similar: 79% in the retrograde group and 78% in the antegrade group. Failures became evident within 2 to 4 months after the procedure. In the antegrade group 5 patients failed initial endopyelotomy. Of these 5 patients 1 was cured with reincision of the ureteropelvic junction. One patient had a large peripelvic urinoma in the immediate postoperative period, which was drained percutaneously. Two months later she underwent dismembered pyeloplasty due to recurrent stricture at the ureteropelvic junction. At operation, the ureteropelvic junction was patent and she also had a large adynamic renal pelvis, which could explain the poor result. For the other 4 patients with recurrent ureteropelvic junction stricture we could find no obvious cause. There were 3 failures in the retrograde group. In 2 of the 3 patients the kidney had poor function at the outset (15% or less on renal scan), a factor that may have contributed to the recurrent ureteropelvic junction stricture. Also, 2 of these 3 patients had a large perirenal hematoma in the immediate postoperative period, which also might have interfered with healing of the ureteropelvic junction. In 1 patient the recurrent ureteropelvic junction obstruction resolved successfully with reincision. From our experience, we currently conclude that an antegrade approach to endopyelotomy is preferable to a retrograde approach. The success rate is equivalent and the incidence of significant complications is less. However, the entire field of endopyelotomy is in a state of flux. Certainly, the retrograde approach is still attractive and it remains for other investigators to overcome the problems we have encountered. Indeed, already Thomas and Cherry have reported a technique modification that allows for a more rapid and possibly safer retrograde approach. 50 Specifically, by placing a small indwelling ureteral stent for 1 week before planned retrograde endopyelotomy they eliminated the need to dilate the distal ureter at the endoscopic retrograde approach. Early results appear to be equivalent to t he antegrade approach and, to date, no distal ureteral strictures have occurred. Similarly, Figenshau et al have described a 24F electrocautery cutting balloon* that allows the operator to incise the ureter retrograde under fluoroscopic control without the need for ureteroscopy. 51 T he electrocautery cutting wire is only 100 µ. in diameter. Initial animal studies have revealed that the fluoroscopically controlled balloon incision is extremely fine and the acute peri-incisional injury is less than or equal to that incurred with endoscopic endoureterotomy performed with a cold knife or neodymium:YAG laser. With regard to endopyelotomy, regardless of t he approach many procedural variables must be considered. Specifically, the etiology of the obstruction, met hod of incision, stent size and stent duration may each impact upon endopyelotomy outcome. We noted a slightly, albeit not statistically, significant improve* Applied Urology, Laguna H ills, California.
ENDOPYELOTOMY: COMPARISON OF TECHNIQUES
ment in results for treating secondary ureteropelvic junction obstruction as opposed to primary ureteropelvic junction obstruction. Other investigators have also noted improved results in patients with secondary ureteropelvic junction obstruction. However, it is important to realize that even among patients with primary ureteropelvic junction obstruction the success rate compares favorably with that of an open procedure (table 5). Stent size may have a role in the final outcome. In our series 2 of 7 patients (29%) with a standard 7F stent failed endopyelotomy. In contrast, with the larger variable sized 7F /14F stent 21 % of the patients failed the procedure. However, this is only a trend and we are as yet unable to show whether this new stent design is of significant benefit. While intrinsically appealing, the virtue of the 7F/14F stent design remains unproved. Nonetheless, we currently prefer that our patients be discharged from the hospital with an indwelling 7F /14F ureteral stent rather than an external nephrostomy stent. Our impression is that the indwelling stent is more comfortable for the patient and that the patient prefers not to have any external catheters. It is of interest that the final outcome, whether a 14F nephrostomy stent or a 7F/14F indwelling stent is used, appears to be similar (table 5). 14 The proper duration of the indwelling stent after endopyelotomy also remains undetermined. Although earlier canine studies with an open intubated ureterostomy suggest that a 6week period is necessary before complete ureteral healing (urothelium and muscle) occurs, clinical experience questions the application of these findings to the human situation. 32 - 34 Indeed, in an extensive series Kuenkel and Korth 14 concluded that a 3-week period of stinting was actually preferable to the current 6-week standard. 52 Further basic and clinical studies are needed to determine the optimal duration of stinting. Lastly, there is some question as to the safety of electrocautery in the ureter. Upon review of the failures in the retrograde group, it became apparent that all 3 failed patients were incised with a 2F or 3F Greenwald electrode. However, all incisions in the retrograde group were also made with 2F to 5F Greenwald electrode. Of the 5 failures in the antegrade group 2 incisions were made with a 3F or 5F Greenwald electrode, 1 with a Collings knife and 1 with a cold knife. Interestingly, our overall success rate was similar regardless of use of a cold knife (11 % failure rate) or an electrocautery probe (13% failure rate, table 5). Therefore, we believe that with 1 caveat electrocautery in the ureter is safe. Specifically, a 250 to 400 µ. tip electrode operating on pure cut at 50 to 100 watts should be used. Larger electrocautery probe tips (1,000 µ.) can be damaging. Indeed, our laboratory studies revealed no difference in the acute dam age to a pig ureter from a cold knife and a 250 or 660 /.L tipped electrode (2F to 3F shaft). However, larger 5F electrodes, with a 1,000 µ. tip, were associated with increased local acute inflammation and peri-incisional injury. 51 This problem with the larger electrocautery probes could well explain some of the earlier admonitions regarding electrocautery incision in the ureter. 53 Also, an additional benefit of using electrocautery over a ureterotomy blade to incise the ureter is that any bleeding from small periureteral vessels can be stopped by precise electrocoagulation, thereby precluding the development of a periureteral hematoma. Presently, the indications for endopyelotomy in adults are broad. Indeed, while results are somewhat improved for secondary ureteropelvic junction obstruction (75 to 100% ), the outcome for primary ureteropelvic junction obstruction is also favorable (71 to 89%, table 5). In children endopyelotomy has been performed rarely and then predominantly only for secondary obstruction following open pyeloplasty. However, in those few cases the successful salvage rate with endopyelotomy has been excellent irrespective of patient age (6 weeks old or older). 54 The only absolute contraindication to endopyelotomy is a
completely obstructed ureteropelvic junction. In this circumstance, while there have been isolated case reports of reestablishing continuity by cutting to the light, an open procedure currently is the standard of care in the urological community. Further evaluation of the long-term success rate of endopyelotomy for the totally obstructed ureteropelvic junction will be necessary to determine accurately the role of endopyelotomy under this specific circumstance. With regard to patients with partial obstruction at the ureteropelvic junction, there are only a few contraindications to endopyelotomy. A poorly functioning adult kidney due to ureteropelvic junction obstruction will probably respond poorly to endopyelotomy. Therefore, if the overall function of the affected kidney is less than 10 to 15%, we believe that nephrectomy is the preferred form of therapy. Ureteropelvic junction obstruction associated with large (that is giant) pyelectasis is better treated by an open operation in which pyeloplasty and plastic tapering of the renal pelvis can be accomplished. While endopyelotomy may provide a more patent ureteropelvic junction, it will not improve emptying of the system if the pelvis is truly phlegmatic due to its exaggerated size. Also, we and others do not believe that a high ureteral insertion into the renal pelvis is a contraindication to endopyelotomy. 5 Our patients with this anatomical situation did as well as other patients with a low insertion. Finally, while ureteropelvic junction blockage due to a crossing vessel is cited as an absolute contraindication, among our initial 42 cases and in 40 subsequent cases we have yet to identify a posterior crossing vessel. Indeed, in our series 2 arteriograms were performed in patients with an IVP suspicious for this entity and both angiograms failed to reveal an obstructing lower pole renal artery. Also, these aberrant obstructing vessels classically cross the ureteropelvic junction anteriorly, while endopyelotomy is always performed posteriorly or posterolaterally. Therefore, in the rare circumstance of ureteropelvic junction blockage from a posteriorly crossing segmental vessel there is a potential for significant hemorrhage. Indeed, this may have been the cause of bleeding in 1 or all of our 4 patients who required transfusion. However, this single possibility continues to concern us and, therefore, we prefer to make a precise controlled electrocautery incision to identify any possible larger, posteriorly lying vessels and to fulgurate immediately any smaller crossing vessels that are present. CONCLUSIONS
In this series of 41 patients with 42 ureteropelvic junction strictures the presence of ureteropelvic junction obstruction was documented by an IVP, diuresis renogram and/or a Whitaker test before treatment. The initial success rate for antegrade and retrograde endopyelotomy was similar (78% versus 79% ). Morbidity and hospital stay were identical in both groups. However, the complication rate for retrograde endopyelotomy exceeded that for the antegrade approach due to the development of a distal ureteral stricture in 21 % of the patients. Presently, we prefer an antegrade approach via an 18F nephrostomy tract. In comparison with standard open pyeloplasty, endopyelotomy has a slightly lower long-term success rate. However, we believe that the smaller skin incision, briefer hospital stay and minimal morbidity associated with endopyelotomy have made it the procedure of choice among the majority of adults with either primary or secondary ureteropelvic junction obstruction. REFERENCES
1. Albarran, J.: Operations plastiques et anastomoses clans la trait-
ment des retentions de veim. These DeParis, 1903. 2. Davis, D. M.: Intubated ureterotomy: a new operation for ureteral and ureteropelvic strictures. Surg., Gynec. & Obst., 76: 513, 1943. 3. Wickham, J. E. A.: Percutaneous pyelolysis. In: Percutaneous Renal Surgery. Edited by J. E. A. Wickham and R. A. Miller. New York: Churchill Livingstone, chapt. 6, pp. 148-154, 1983.
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4. Badlani, G., Eshghi, M. and Smith, A. D.: Percutaneous surgery for ureteropelvic junction obstruction (endopyelotomy): technique and early results. J. Urol., 135: 26, 1986. 5. Van Cangh, P. J., Jorion, J. L., Wese, F. X. and Opsomer, R. J.: Endoureteropyelotomy: percutaneous treatment of ureteropelvic junction obstruction. J. Urol., 141: 1317, 1989. 6. Ramsey, J. W. A., Miller, R. A., Kellett, M. J., Blackford, H. N., Wickham, J.E. A. and Whitfield, H. N.: Percutaneous pyelolysis: indications, complications and results. Brit. J. Urol., 56: 586, 1984. 7. Clayman, R. V. and Picus, D. D.: Ureterorenoscopic endopyelotomy: preliminary report. Urol. Clin. N. Amer., 15: 433, 1988. 8. Clayman, R. V., Basler, J. W., Kavoussi, L. and Picus, D. D.: Ureteronephroscopic endopyelotomy. J. Urol., 144: 246, 1990. 9. Clayman, R. V., Bub, P., Haaff, E. and Dresner, S.: Prone flexible cystoscopy: an adjunct to percutaneous stone removal. J. Urol., 137: 65, 1987. 10. Kavoussi, L. R. and Clayman, R. V.: Flexible endoscopy of the urinary tract part II. AUA Update Series, vol. VIII, lesson 6, pp. 41-48, 1989. 11. Scardino, P. T. and Scardino, P. L.: Obstruction at the ureteropelvic junction. In: The Ureter, 2nd ed. Edited by H. Bergman. New York: Springer-Verlag, chapt. 33, pp. 697-716, 1981. 12. Karlin, G. S. and Smith, A. D.: Endopyelotomy. Urol. Clin. N. Amer., 15: 439, 1988. 13. Weiss, J. N., Badlani, G. H. and Smith, A. D.: Complications of endopyelotomy. Urol. Clin. N. Amer., 15: 449, 1988. 14. Kuenkel, M. and Korth, K.: Endopyelotomy: long-term follow-up of 143 patients. J. Endourol., 4: 109, 1990. 15. Koff, S. A.: Ureteropelvic junction obstruction: role of newer diagnostic methods. J. Urol., 127: 898, 1982. 16. Schaeffer, A. J. and Grayhack, J. T.: Surgical management of ureteropelvic junction obstruction. In: Campbell's Urology, 5th ed. Edited by P. C. Walsh, R. F. Gittes, A. D. Perlmutter and T. A. Stamey. Philadelphia: W. B. Saunders Co., vol. 3, sect. XV, chapt. 65,pp. 2503-2533, 1986. 17. Roberts, J.B. and Slade, N.: The natural history of primary pelvic hydronephrosis. Brit. J. Surg., 51: 759, 1964. 18. Whitaker, R. H.: Methods of assessing obstruction in dilated ureters. Brit. J. Urol., 45: 15, 1973. 19. Whitaker, R. H.: Clinical assessment of pelvic and ureteral function. Urology, 12: 146, 1978. 20. Blute, M. L. and Malek, R. S.: Contemporary concepts in diagnosis and management of ureteropelvic junction obstruction in adults. AUA Update Series, vol. IX, lesson 5, pp. 33-40, 1990. 21. Murphy, L. J. T.: The kidney. In: The History of Urology. Springfield, Illinois: Charles C Thomas, Publishers, chapt. 8, pp. 197208, 1972. 22. Karlin, G. S., Badlani, G. H. and Smith, A. D.: Endopyelotomy versus open pyeloplasty: comparison in 88 patients. J. Urol., 140: 476, 1988. 23. Nguyen, D. H., Aliabadi, H., Ercole, C. J. and Gonzalez, R.: Nonintubated Anderson-Hynes repair of ureteropelvic junction obstruction in 60 patients. J. Urol., 142: 704, 1989. 24. Johnston, J. H., Evans, J. P., Glassberg, K. I. and Shapiro, S. R.: Pelvic hydronephrosis in children: a review of 219 personal cases. J. Urol., 117: 97, 1977. 25. Hendren, W. H., Radhakrishnan, J. and Middleton, A. W., Jr.: Pediatric pyeloplasty. J. Ped. Surg., 15: 133, 1980. 26. Persky, L., Krause, J. R. and Boltuch, R. L.: Initial complications and late results in dismembered pyeloplasty. J. Urol., 118: 162, 1977. 27. Bratt, C.-G. and Nilsson, S.: Late results after surgical correction ofpyelopfasty failure in idiopathic hydronephrosis. J. Urol., 132: 231, 1984. 28. Kelalis, P. P., Culp, 0. S., Stickler, G. B. and Burke, E. C.: Ureteropelvic obstruction in children: experiences with 109 cases. J. Urol., 106: 418, 1971. 29. Saing, H., Chan, F. L., Yeung, C. K. and Yeung, D. W. C.: Pediatric pyeloplasty: 50 patients with 59 hydronephrotic kidneys. J. Ped. Surg., 24: 346, 1989. 30. Davis, D. M., Strong, G. H. and Drake, W. M.: Intubated ureterotomy: experimental work and clinical results. J. Urol., 59: 851, 1948. 31. Davis, D. M.: Intubated ureterotomy. J. Urol., 66: 77, 1951. 32. Oppenheimer, R. and Hinman, F., Jr.: Ureteral regeneration: contracture vs hyperplasia of smooth muscle. J. Urol., 74: 476, 1955.
33. Hamm, F. C. and Weinberg, S. R.: Renal and ureteral surgery without intubation. J. Urol., 73: 475, 1955. 34. Hamm, F. C. and Weinberg, S. R.: Experimental studies of regeneration of the ureter without intubation. J. Urol., 75: 43, 1956. 35. Webb, E. A., Smith, B. A., Jr. and Price, W. E.: Plastic operations on the ureter without intubation. J. Urol., 77: 821, 1957. 36. Mahoney, S. A., Koletsky, S. and Persky, L.: Approximation and dilatation: the mode of healing of an unintubated ureterostomy. J. Urol., 88: 197, 1962. 37. Bagley, D. H., Huffman, J., Lyon, E. and McNamara, T.: Endoscopic ureteropyelostomy: opening the obliterated ureteropelvic junction with nephroscopy and flexible ureteropyeloscopy. J. Urol., 133: 462, 1985. 38. Inglis, J. A. and Tolley, D. A.: Ureteroscopic pyelolysis for pelviureteric junction obstruction. Brit. J. Urol., 58: 250, 1986. 39. Badlani, G. H., Karlin, G. and Smith, A. D.: Complications of endopyelotomy: analysis in series of 64 patients. J. Urol., 140: 473, 1988. 40. Sosa, R. E., Bagley, D. H. and Huffman, J. L.: Complications of ureteropyeloscopy. In: Ureteroscopy. Edited by J. L. Huffman, D. H. Bagley and E. S. Lyon. Philadelphia: W. B. Saunders Co., chapt. 11,pp. 157-168, 1988. 41. Kramolowsky, E. V .: U reteral perforation during ureterorenoscopy: treatment and management. J. Urol., 138: 36, 1987. 42. Schultz, A., Kristensen, J. K., Blide, T. and Eldrup, J.: Ureteroscopy: results and complications. J. Urol., 137: 865, 1987. 43. Flam, T. A., Malone, M. J. and Roth, R. A.: Complications of ureteroscopy. Urol. Clin. N. Amer., 15: 167, 1988. 44. Blute, M. L., Segura, J. W. and Patterson, D. E.: Ureteroscopy. J. Urol., 139: 510, 1988. 45. Kavoussi, L., Clayman, R. V. and Basler, J.: Flexible, actively deflectable fiberoptic ureteronephroscopy. J. Urol., 142: 949, 1989. 46. Huffman, J. L.: Ureteroscopy. In: Monographs in Urology. Edited by T. A. Stamey. Vol. 9, No. 1, 1988. 47. Miller, R. A.: Endoscopic surgery of the upper urinary tract. Brit. Med. Bull., 42: 274, 1986. 48. Weinberg, J. J., Ansong, K. and Smith, A. D.: Complications of ureteroscopy in relation to experience: report of survey and author experience. J. Urol., 137: 384, 1987. 49. Ford, T. F., Parkinson, M. C. and Wickham, J. E. A.: Clinical and experimental evaluation of ureteric dilation. Brit. J. Urol., 56: 460, 1984. 50. Thomas, R. and Cherry, R.: Ureteroscopic endopyelotomy for management of ureteropelvic junction obstruction. J. Endourol., suppl. 1, 4: S141, abstract S-15, 1990. 51. Figenshau, R. S., Stone, A. M., Wick, M. R. and Clayman, R. V.: Acute histologic changes associated with endourologic manipulations in the normal pig ureter. J. Endourol., suppl. 1, 5: S63, abstract P. 11-4, 1991. 52. Badlani, G. H. and Smith, A. D.: Stent for endopyelotomy. Urol. Clin. N. Amer., 15: 445, 1988. 53. King, L. R., Coughlin, P. W. F., Ford, K. K., Brown, M. W. and Van Moore, A.: Initial experiences with percutaneous and transurethral ablation of postoperative ureteral strictures in children. J. Urol., 131: 1167, 1984. 54. Kavoussi, L. R., Meretyk, S., Dierks, S. M., Bigg, S. W., Gup, D. I., Manley, C. B., Shapiro, E. and Clayman, R. V.: Endopyelotomy for secondary ureteropelvic junction obstruction in children. J. Urol., 145: 345, 1991.
EDITORIAL COMMENTS Endopyelotomy has become a standard procedure for the treatment of ureteropelvic junction obstruction and the success rates of approximately 80% by the percutaneous and retrograde routes as reported by the authors are consistent with what others have reported in the literature. I have always preferred the antegrade over the retrograde approach because I have always been able to see the area of interest more clearly even in the face of bleeding. Also, the larger instruments available for percutaneous use seem to make the procedure technically simpler and more expeditious. It is probably a reasonable step to compare these 2 different techniques even though the 2 groups are not quite comparable, there being fewer men in the retrograde group due to access difficulties and fewer people in the secondary ureteropelvic junction group than in the retrograde group. The 7F /14F internal stent in my opinion represents an advance in