Holmium: Yag Laser Endoureterotomy For Ureterointestinal Strictures

Holmium: Yag Laser Endoureterotomy For Ureterointestinal Strictures

0022-5347/02/1674-1692/0 THE JOURNAL OF UROLOGY® Copyright © 2002 by AMERICAN UROLOGICAL ASSOCIATION, INC.® Vol. 167, 1692–1695, April 2002 Printed i...

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0022-5347/02/1674-1692/0 THE JOURNAL OF UROLOGY® Copyright © 2002 by AMERICAN UROLOGICAL ASSOCIATION, INC.®

Vol. 167, 1692–1695, April 2002 Printed in U.S.A.

HOLMIUM:YAG LASER ENDOURETEROTOMY FOR URETEROINTESTINAL STRICTURES JAMES D. WATTERSON, MARIO SOFER, TIMOTHY A. WOLLIN, LINDA NOTT JOHN D. DENSTEDT*

AND

From the Division of Urology, University of Western Ontario, London, Ontario, Canada

ABSTRACT

Purpose: The management of ureterointestinal stricture in patients who have undergone urinary diversion can be challenging. Endourological techniques have been increasingly used in recent years for ureteral stricture. While long-term results may not be as reliable or durable as those of traditional open reconstructive surgical techniques, associated morbidity is much less. The holmium (Ho):YAG laser, which has cutting and coagulating properties, has been demonstrated to have many applications in urology. We report our experience with and long-term results of Ho:YAG laser endoureterotomy for ureterointestinal strictures. Materials and Methods: We reviewed the charts and followup history of 23 patients in whom the Ho:YAG laser was used to treat ureterointestinal anastomotic stricture. Strictures were treated percutaneously via the antegrade approach with flexible endoscopes and the holmium laser. A reversed 12/6Fr endopyelotomy stent was left indwelling for 6 weeks postoperatively. Success was defined as symptomatic improvement and radiographic resolution of obstruction. Results: Between 1993 and 2000, 23 patients with a mean age of 61 years underwent endoureterotomy using the Ho:YAG laser for 24 ureterointestinal stricture. An overall success rate of 71% (17 of 24 cases) was achieved at a mean followup of 22 months. The success rate of holmium laser endoureterotomy for ureterointestinal stricture at 1, 2 and 3 years was 85%, 72% and 56%, respectively. Seven patients had recurrent strictures of which 4 developed 16 months or more postoperatively. No complications were noted. Conclusions: Ho:YAG laser endoureterotomy for ureterointestinal stricture disease is a minimally invasive endourological procedure that may provide more durable results than other modalities used for endoureterotomy. The Ho:YAG laser with its ability to cut tissue precisely and provide hemostasis combined with its versatility and compatibility with flexible endoscopes is an ideal instrument for safely performing endoureterotomy. KEY WORDS: ureter, urinary diversion; anastomosis, surgical; laser surgery; endoscopy

The management of ureterointestinal stricture in patients who have undergone urinary diversion presents a particular challenge for urologists. The reported incidence of ureterointestinal stricture is 4% to 8% in patients who undergo ureteral ileal conduit procedures1, 2 with a higher rate of stenosis in those with nonrefluxing continent urinary diversions (13%)3 or ureterosigmoidostomy (22%).4 The development of stricture at the ureterointestinal anastomosis traditionally required laparotomy and revision of the anastomosis with reimplantation of the viable ureter into the urinary diversion. Advances in endourological techniques and instrumentation as well as in interventional radiology have led to a minimally invasive approach to ureterointestinal stricture, resulting in decreased morbidity, operative time, hospitalization and cost compared with open reconstruction. Various endourological techniques have been described for ureterointestinal stricture, including cold knife and electrosurgical endoureterotomy, balloon dilation and Acucise (Applied Medical Technologies, Laguna Hills, California) endoureterotomy. The endoureterotomy success rate at various followup intervals is 33% to 65% for the treatment of ureterointestinal stricture using these various modalities.5–10 The holmium (Ho):YAG laser is a relatively new multipurpose medical laser that is rapidly becoming an integral part of the endourological armamentarium in laser lithotripsy and numerous soft tissue applications. With ablative and hemostatic properties the Ho:YAG laser provides precise tissue incision and hemostasis, while limiting surrounding tissue damage, Accepted for publication November 16, 2001.

making it an ideal modality for endoureterotomy. We review our surgical technique and results of Ho:YAG laser endoureterotomy for the endourological management of ureterointestinal stricture. MATERIALS AND METHODS

Between 1993 and 2000, 23 patients presenting with a total of 24 ureterointestinal strictures after urinary diversion underwent endoureterotomy using the Ho:YAG laser. Mean age at presentation was 61 years (range 31 to 81). Of the patients 10 (43%) were female and 13 (57%) were male. The indications for cystectomy and ileal conduit urinary diversion were bladder transitional cell carcinoma in 16 patients (70%), cervical carcinoma requiring pelvic exenteration in 1 and various benign bladder conditions in 7 (30%). Of the patients (63%) presented with a stricture on the left side and a third presented with a stricture on the right side. The 11 patients (48%) who were asymptomatic at presentation were diagnosed at routine radiographic surveillance, 6 (26%) presented with biochemical and/or clinical evidence of renal failure, and 9% each presented with flank pain, pyelonephritis and urosepsis. In a patient who presented with bilateral ureterointestinal stricture 2 strictures were treated at the same session. Previous stricture treatment with balloon dilation in 2 cases and open revision in 2 had failed, while 7 (30%) presented for treatment with a previously placed indwelling percutaneous nephrostomy tube. The mean interval between urinary diversion and endoureterotomy was 45

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HOLMIUM:YAG LASER ENDOURETEROTOMY FOR STRICTURES

months (range 1 to 432). No patient previously underwent pelvic or abdominal radiotherapy. Patients were evaluated preoperatively by standard history and physical examination, renal function studies, urinary cytology, urine culture to exclude urinary tract infection and appropriate radiographic imaging. Abdominal computerized tomography (CT) was performed in all cases to exclude recurrent malignancy and allow adequate assessment of the spatial relationship of the stricture to adjacent organs and vascular structures. Adjunctive imaging studies, such as ultrasound, excretory urography, loopography and antegrade nephrostography were performed in select patients to document adequately the location, length and degree of stricture patency. Patients with complete anastomotic occlusion were excluded from Ho:YAG laser endoureterotomy and advised to undergo open surgical reconstruction. Informed consent was obtained. All procedures were performed with the patient prone under general anesthesia. A broad-spectrum antibiotic was administered intravenously for prophylaxis in all cases. A catheter was placed within the conduit for drainage. Under fluoroscopic guidance percutaneous renal access was achieved via a superior or mid pole posterior calix to provide straight access tract to the stenotic segment. The tract was dilated to 30Fr using semirigid Amplatz dilators or a balloon dilator. Ureterointestinal stricture location and length were evaluated by antegrade pyelography. A 0.035-inch Bentson guide wire was advanced across the stenotic segment into the ileal conduit. When traversing tightly stenotic ureteral segments, it was invaluable to use hydrophilic guide wires buttressed by 5Fr open-ended catheters or angled catheters. Guide wire passage under direct endoscopic vision was a final option. After through-and-through access was achieved endoscopic inspection was performed beside the wire to define further the stenosed length of ureter. A 15Fr flexible nephroscope was usually sufficient to access the stenotic segment due to proximal ureteral dilation. If the stenosed segment was not accessible, particularly left strictures, a 7.5Fr flexible ureteroscope was used. During inspection the length, location, degree of stenosis and presence of pulsations were assessed. Endoscopic findings were correlated with preoperative imaging to avoid injury to adjacent structures. If the strictured ureter did not accommodate the endoscope, the area was calibrated using a 6 mm. ⫻ 10 cm. balloon dilation catheter. Partial balloon inflation provided additional information on stricture compliance and resulted in minimal dilation to facilitate endoscope passage. Endoureterotomy was performed using a pulsed 80 W. Ho:YAG laser combined with a 365 ␮m. end-firing laser fiber. The fiber was extended 2 to 3 mm. beyond the tip of the endoscope and placed in direct contact with the tissue to be incised. The parameters used for endoureterotomy were 0.6 to 2 J. per pulse at a pulse rate of 8 to 15 Hz.11 A fullthickness incision was made into retroperitoneal fat, extending 5 mm. above and below the lesion. The site of endoscopic incision was individualized in each procedure. Direct endoscopic inspection of the stricture was correlated with preoperative radiographic imaging to avoid vascular pulsations and subsequent injury. After laser incision the segment was completely dilated using an 8 mm. ⫻ 10 cm. balloon dilation catheter. Endoscopic incision was repeated as necessary, particularly if persistent waisting due to extensive fibrosis was noted. Ancillary incisional techniques, such as cold knife or electrocautery, were not required in any procedure and fullthickness incision was accomplished in all cases. Extravasation of contrast material was documented by fluoroscopy. A reversed 6/12Fr endopyelotomy stent was placed in antegrade fashion and left indwelling for 6 weeks. A 16 to 18Fr nephrostomy tube remained indwelling for 24 to 48 hours.

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Followup scheduled every 3 months for the first year and biannually thereafter consisted of assessment of symptomatology, determination of renal function and radiographic imaging with ultrasound, excretory urography, loopography or CT. Success was defined as symptomatic improvement, and/or absence of obstruction or stricture on postoperative imaging. Time to the last radiographic followup in successfully treated patients and time to failure were considered the censor and end points, respectively, for constructing KaplanMeier curves.12 Clinical, anatomical and pathological factors were analyzed as prognostic factors to predict the outcome using Fisher’s exact test for categorical data and the MannWhitney U test for continuous data with p ⱕ0.05 considered significant. RESULTS

A single attempt at laser endoureterotomy with the Ho: YAG laser was performed in all cases. All patients were treated on an inpatient basis with an average hospitalization of 2 days (range 1 to 4). Mean operative time was 75 minutes (range 30 to 240). Direct endoscopic visualization of the incised area was possible in all cases. Mean stricture length was 1.7 cm. (range 0.5 to 5). Average laser pulse energy and pulse rate were 0.9 J. (range 0.5 to 2) and 13 Hz. (range 8 to 15), respectively. Blood loss was minimal and the laser provided excellent hemostasis, allowing a clear field of view throughout the procedure. No intraoperative complications were noted. The overall success rate was 70.8% (17 of 24 patients) at a mean followup of 22.5 months (range 3 to 68). The success rate of Ho:YAG laser endoureterotomy for ureterointestinal stricture at 1, 2 and 3 years was 85%, 72% and 56%, respectively. The figure shows a Kaplan-Meier curve of success versus the time from Ho:YAG laser endoureterotomy for ureterointestinal stricture. The simple success rate in patients followed more than 12 months was 81% (13 of 16). The side and length of the stricture, interval between diversion and endoureterotomy, laser pulse energy, drainage before endoureterotomy, and patient age and gender were analyzed as possible prognostic factors (see table). Statistical analysis did not identify any differences in patients in whom endoureterotomy succeeded and failed. Although it was not statistically significant, patients with a right stricture, a stricture less than 10 mm. or urinary tract drainage before endoureterotomy fared better. In patients with failure cystectomy was performed for muscle invasive transitional cell carcinoma. In 3 cases treatment failed within year 1 postoperatively at 4, 7 and 10 months, respectively. More importantly, treatment failed in 4 cases after 1 year at 16 months in 1, 23 in 1 and 29 in 2. Failure was managed by successful open revision in 1 patient, nephroureterectomy due to recur-

Kaplan-Meier curve shows success rate of Ho:YAG laser endoureterotomy for ureterointestinal strictures. Values in parentheses indicate number of patients at risk at 12, 24 and 36 months.

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HOLMIUM:YAG LASER ENDOURETEROTOMY FOR STRICTURES Success rate after Ho:YAG laser endoureterotomy No. Pts./No. Successes (%)

Factor Side: Lt. Rt. Mos. from diversion to endoureterotomy: 24 or Greater Less than 24 Stricture length (cm.): 1 or Less Greater than 1 Stent or PCN drainage before endoureterotomy: Yes No Laser pulse energy (mean J./pulse): Success Failure Mean pt. age: Success Failure

p Value 0.19

15/9 (60) 9/8 (89) 1 7/5 (71) 10/7 (70) 0.12 10/9 (90) 8/4 (50) 0.07 7/7 (100) 17/10 (59) 0.56 0.95 0.91 0.73 60.9 66.3

rent transitional cell carcinoma (malignant stricture) in 1 and permanent nephrostomy or indwelling stent drainage in the remaining 5. DISCUSSION

Ureteroenteric stricture develops in 4% to 8% of patients who undergo urinary diversion.1, 2 Stricture occurs more commonly on the left side secondary to resultant ischemia produced during mobilization of the distal ureter beneath the sigmoid colon.1, 13 Important factors for avoiding anastomotic stricture include meticulous surgical technique involving mobilization of the sigmoid mesentery cephalad to the origin of the inferior mesenteric artery to avoid obstruction of the left ureter, preservation of the ureteral adventitia to optimize the blood supply and the use of soft stents postoperatively.14, 15 Standard treatment for ureterointestinal anastomotic stricture is open surgical reimplantation, for which a success rate of 89% was reported.16 Open surgical revision can be difficult to perform due to dense adhesions caused by previous surgery or fibrosis arising from radiotherapy. Advances in endourological techniques and refinements in instrumentation have provided alternate, minimally invasive therapeutic options. Currently the endourological techniques for managing ureteroileal stricture do not have the same success rates as open surgery. However, these approaches are preferred for initial treatment because of decreased associated morbidity, operative time, hospitalization and cost. If required, subsequent open revision does not seem to be compromised by initial endourological procedures. Endosurgical approaches to ureteral stricture have been proposed for more than a century. In 1890 Kelly recommended using a catheter to dilate a ureteral stricture.17 In 1924 Hunner reported good results with placement of a ureteral catheter left indwelling for short periods.18 Advances in ureteral stent technology during the 1970s led to the role of ureteral stents for stricture management and internal urinary drainage.19 In the 1980s with the development of high pressure arterial balloon dilating catheters dilation under fluoroscopic control was performed for the first time for treating ureteral stricture.20 However, ureteral dilation appears to be most successful for nonanastomotic strictures rather than for obstruction after urinary diversion.21 A longterm patency rate of 0% to 61% was reported in patients with ureteroenteric strictures managed by dilation alone.22, 23 Balloon dilation of ureteroenteric strictures does not incise the scar and enable ureteral regeneration from healthy tissue. Furthermore, concern regarding ischemic changes in the surrounding healthy ureter due to hydraulic trauma has led most investigators to recommend against balloon dilation alone for initial management of ureteral stricture disease.24

Endoureterotomy, that is endoscopic incision of a stricture, involves direct vision or fluoroscopy guided incision of the involved area. Performing endoureterotomy for ureteral stricture is based on the principles of the Davis intubated ureterotomy, as originally described in the 1940s.25 The endoureterotomy incision can be created with various cutting devices, including the cold knife, electrocautery, cutting balloon catheter and laser. Endoureterotomy cold knife or electrocautery series show a patency rate of 57% to 71% at greater than 12-month followup,7, 8 decreasing to 32% at 3-year followup.26 Endoureterotomy series using the Acucise cutting balloon catheter for ureterointestinal stricture indicate a patency rate of 30%,27 50%9 and 68%10 at a mean followup of 18, 7.8 and 25 months, respectively. Lasers that are currently available for endoscopic stricture incision include the neodymium:YAG, semiconductor diode with contact fibers, potassium-titanyl-phosphate neodymium:YAG and Ho:YAG lasers.13 The Ho:YAG laser is a solidstate laser system that operates at a wavelength of 2,100 nm. in pulsed mode. This wavelength provides the unique properties associated with the Ho:YAG laser. The Ho:YAG laser is rapidly becoming the modality of choice for intracorporeal ureteroscopic lithotripsy and it also has many potential soft tissue applications. The 2,100 nm. Ho:YAG laser has been shown to have ablative and hemostatic properties, and because laser light can be passed down small optical fibers, these actions can be performed using flexible endoscopes in a fluid environment.28 Precise incisions to a depth of less than 0.5 mm. with good hemostasis are possible. Tissue studies using the Ho:YAG laser show that the zone of thermal injury associated with laser ablation is 0.5 to 1 mm.29 The ability of the Ho:YAG laser to make accurate incisions, while providing hemostasis, may offer an advantage over a cold knife ureterotome, in which hemostasis, when required, can only be effected with the subsequent use of electrocautery. Furthermore, endoureterotomy performed with electrocautery or the Acucise cutting balloon catheter risks possible injury to surrounding healthy tissue due to increased energy transmission. The Ho:YAG laser offers an additional potential advantage over the Acucise catheter through the direct visual application of the laser energy. The Acucise catheter, in which the cutting element cannot be directly visualized at operation, may carry potentially elevated risks through application of this energy to healthy tissue or structures beyond the scar. Several examples in the literature involve injury to adjacent structures sustained during Acucise catheter use. A single case of a ureteroenteric fistula that healed over a ureteral stent without surgery was reported by Meretyk et al.7 Others reported injury to the internal iliac artery, which is a complication with potentially fatal consequences.8, 30 Despite these apparent theoretical advantages of endoureterotomy using the Ho:YAG laser no randomized controlled trials support the benefits of 1 cutting modality over the others.13, 26 The Ho:YAG laser is currently the modality of choice for endoureterotomy at our institution. Despite reports of endoureterotomy performed for complete occlusive strictures,31 our practice is to recommend open surgical reconstruction in these patients and reserve Ho:YAG laser endoureterotomy for incomplete strictures. Our early clinical results with the Ho:YAG laser in 22 patients with nonenteral ureteral strictures had a success rate of 76% (16 of 21) at a mean followup of 10.8 months.32 In patients with ureterointestinal strictures the success rate was 89% (8 of 9) during the same period. Our long-term results confirm that the Ho:YAG laser is a reliable modality for endoureterotomy for ureterointestinal strictures, providing excellent patency rates of 85, 72, and 56% at 1, 2 and 3 years, respectively. Although it was not statistically significant, cases of a stricture of less than 10 mm. trended toward greater success (p ⫽ 0.118), coinciding with previous study results.5, 33 The

HOLMIUM:YAG LASER ENDOURETEROTOMY FOR STRICTURES

side of stricture, interval between diversion time and endoureterotomy, laser pulse energy, drainage before endoureterotomy and gender did not predict the outcome. We realize that the study design and small number of patients does not allow conclusive statements regarding which factors predict outcome. Furthermore, 2 failures 29 months postoperatively support the basis for continued clinical and radiological surveillance beyond year 1 and likely indefinitely. In patients who undergo urinary diversion for malignancy restenosis after Ho:YAG laser endoureterotomy for ureterointestinal strictures should receive a thorough evaluation for the possibility of recurrent malignancy. Repeat evaluation with CT, urinary cytology, antegrade contrast studies and possibly endoscopic visualization would help to identify these patients and guide appropriate therapy.

10. 11. 12. 13. 14.

15. CONCLUSIONS

The main limitation of the Ho:YAG laser is its overall cost with an initial start-up cost of $80,000 to $140,000. However, because of its versatility in the field of urology, specifically for laser lithotripsy and various soft tissue applications, and its potential uses in other surgical specialties the Ho:YAG laser is proving to be a cost-effective tool. In addition, recent generation, low power Ho:YAG lasers with sufficient wattage to perform all urological applications except prostate resection are becoming available at a lower capital cost. For treating ureteral stricture disease, particularly ureterointestinal stricture, the holmium laser would seem to be an ideal tool. Advantages include the accurate control of energy delivery and incision, hemostasis of superficial blood vessels, a narrow zone of thermal injury that should limit damage to surrounding normal tissue, small caliber fibers that allow excellent irrigation and the ability to treat stricture in the upper urinary tract because of its compatibility with flexible endoscopes. These variables offer distinct advantages over existing modalities for endoureterotomy and may result in improved long-term success in this challenging patient population.

16.

17. 18. 19. 20. 21. 22. 23. 24.

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