COMPARISON OF PERCUTANEOUS NEPHROLITHOTOMY AND URETEROSCOPIC LITHOTRIPSY IN THE MANAGEMENT OF IMPACTED, LARGE, PROXIMAL URETERAL STONES

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1 COMPARISON OF PERCUTANEOUS NEPHROLITHOTOMY AND URETEROSCOPIC LITHOTRIPSY IN THE MANAGEMENT OF IMPACTED, LARGE, PROXIMAL URETERAL STONES Yung-Shun Juan, 1 Jung-Tsung Shen, 1 Ching-Chia Li, 2 Chii-Jye Wang, 1,3 Shu-Mien Chuang, 4 Chun-Hsiung Huang, 2,3 and Wen-Jeng Wu 2,3 1 Department of Urology, Kaohsiung Municipal Hsiao-Kang Hospital, 2 Department of Urology, Kaohsiung Medical University Hospital, and Departments of 3 Urology and 4 Anatomy, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. The optimal treatment for large, impacted, proximal ureteral stones remains controversial. We report our experience and compare treatment outcomes in patients with single, impacted, proximal ureteral stones undergoing percutaneous nephrolithotomy (PCNL) and ureteroscopic lithotripsy (URSL). Between January 2005 and January 2006, a total of 53 consecutive patients with solitary, impacted, proximal ureteral stones > 15 mm in diameter who had undergone PCNL or URSL treatments were enrolled in this study. The mean age was 48.5 ± 11.8 years. PCNL and URSL were performed in 22 and 31 patients. Stone burdens in the PCNL and URSL groups were ± mm 2 and ± 70.3 mm 2, respectively. The efficiency quotient (EQ) for the PCNL and URSL groups was 0.95 and 0.67, respectively. The stone-free rate at the 1 month follow-up was 95.4% in the PCNL group and 58% in the URSL group (p < 0.001). Two patients in the PCNL group had blood loss requiring transfusion. Eight patients had stones showing upward migration during the URSL procedure, and these stones were subsequently treated by extracorporeal shock wave lithotripsy and PCNL. For an impacted, proximal ureteral stone > 15 mm in diameter, PCNL had better stone-free rates and could simultaneously treat coexisting renal stones. However, URSL had the advantages of shorter operative times, shorter postoperative hospital stays, and fewer postoperative complications. Key Words: percutaneous nephroscopy, ureteral stone, ureteroscopy (Kaohsiung J Med Sci 2008;24:204 9) In the last two decades, the management of urolithiasis has changed profoundly. Ever since the introduction of extracorporeal shock wave lithotripsy (SWL) in 1980 [1,2], it has become the first-line therapy for most renal 204 Received: Dec 29, 2006 Accepted: Apr 25, 2007 Address correspondence and reprint requests to: Dr Wen-Jeng Wu, Department of Urology, Kaohsiung Medical University, 100 Shih-Chuan 1 st Road, Kaohsiung 807, Taiwan. wejewu@kmu.edu.tw and ureteral stones. Nevertheless, the optimal treatment for a large and impacted proximal ureteral stone remains controversial. The outcome of SWL for ureteral stones is determined by various factors, including stone size, location, and composition [3]. Large ureteral stones may require several treatment sessions with SWL. Percutaneous nephrostolithotomy (PCNL) was introduced as an alternative treatment for large renal and proximal ureteral stones, and achieved success in the 1980s [4]. Recently, with the advances in smaller Kaohsiung J Med Sci April 2008 Vol 24 No Elsevier. All rights reserved.

2 Comparison of antegrade and retrograde treatment of stones caliber semi-rigid and flexible ureteroscopes, ureteroscopic lithotripsy (URSL) has reached a good stonefree rate for lower ureteral stones and decreased the risk of complications [5]. Although open surgery is rarely used as first-line therapy, patients with large, impacted, proximal ureteral stones may sometimes require open surgery or laparoscopic ureterolithotomy. Herein, we report our experience of the management of impacted, proximal ureteral stones > 15 mm in diameter and compare the treatment outcomes in patients undergoing PCNL and URSL. In so doing, we have attempted to determine the optimal therapeutic modality for patients with large, impacted, proximal ureteral stones. MATERIALS AND METHODS Fifty-three consecutive patients presenting with a solitary, impacted, proximal ureteral stone between January 2005 and January 2006 were enrolled in this study. The advantages, related complications of either method of treatment and the possibility of conversion to open surgery were explained to the patients preoperatively. The inclusion criteria for treatment were: (1) radioopaque upper ureteral stone > 15 mm in diameter by plain film of kidney, ureter and bladder; (2) ureteral stone located between the upper border of the L5 vertebral body and the ureteropelvic junction (UPJ); and (3) intravenous pyelogram (IVP) confirming impaction of a stone with no visible contrast media below the calculus on any IVP images. Patients with the following conditions were excluded from the study: renal insufficiency with a creatinine > 3.5 mg/dl, history of previous irradiation or pelvic surgery, morbid obesity, and coagulopathy. PCNL was performed using the standard technique of puncture and placement of a nephrostomy tract. The nephrostomy tract was created the day before surgery. The middle posterior calyx was chosen for needle puncture. A core guide wire was negotiated into the renal pelvis and across the UPJ into the ureter. The guide wire was coiled into the calyces to prevent it from being dislocated from the kidney inadvertently. A 10-mm diameter, 8-cm long highpressure balloon dilation catheter (BlueMax; Boston Scientific, Watertown, MA, USA) was used and the nephrostomy tract was dilated to 30 F. The second day, PCNL was performed under general anesthesia with the patient in the prone position. A 26 F rigid nephroscope or semirigid 7 F ureteroscope was introduced through a 30 F Amplatz sheath along the guide wire. Once the proximal ureteral stone was visible, the stone was broken with a LithoClast Ultra (EMS, Nyon, Switzerland), a combination ultrasonic and pneumatic lithotripter unit, and the stone fragments were removed. A double-j catheter was inserted if possible, and a nephrostomy tube was left in place for a few days. URSL was performed with a semi-rigid Storz 6.5 F or Wolf 7 F ureteroscope under epidural anesthesia in the lithotomy position. A ureteral guide wire was used without dilating the ureteral orifice. The stones were fragmented with the LithoClast Ultra or an electrohydraulic lithotripter according to the surgeon s preference. A double-j catheter was placed in patients with intraluminal mucosa edema, ureteral polyps, or ureteral strictures. Stone-free was defined as no residual stones detected on plain abdomen X-ray film 1 month after therapy. We used the efficiency quotient (EQ) to compare the efficiency of both treatment groups. EQ was calculated by the equation: EQ = [percentage stone-free/ (100% + percentage requiring retreatment + percentage requiring an auxiliary procedure) [6]. The results are presented as mean ± standard deviation. All of the parameters were analyzed statistically using the unpaired Student s t test and χ 2 test. A p value < 0.05 was considered statistically significant. RESULTS A total of 53 patients were included in this study, of whom 22 were treated by PCNL and 31 were treated by URSL. The patient demographic and clinical characteristics are summarized in Table 1. There were no significant differences in age, gender, calculus size, and serum BUN level between the two groups of patients. The stone burden was significantly greater in the PCNL group than in the URSL group (232.8 ± mm 2 vs ± 70.3 mm 2, p = 0.006) and the creatinine level was higher in the URSL group. The stone-free rate at the 1 month follow-up visit after initial treatment was 95.4% in the PCNL group and 58% in the URSL group (p < 0.001). The mean treatment time and postoperative hospital stay were Kaohsiung J Med Sci April 2008 Vol 24 No 4 205

3 Y.S. Juan, J.T. Shen, C.C. Li, et al Table 1. Demographic and clinical characteristics of patients in the percutaneous nephrolithotomy (PCNL) and ureteroscopic lithotripsy (URSL) groups* PCNL group (n = 22) URSL group (n = 31) p Age (yr) 48.2 ± ± Men/Women 16/6 23/ BUN (mg/dl) ± ± Creatinine (mg/dl) 1.22 ± ± Stone laterality, R/L 9/13 13/ Stone size (mm) 20.1 ± ± Stone burden (mm 2 ) ± ± *Data presented as mean ± standard deviation or n. BUN = blood, urea, nitrogen; R = right; L = left. Table 2. Stone-free rate, operative finding and postoperative complications in patients in the percutaneous nephrolithotomy (PCNL) and ureteroscopic lithotripsy (URSL) groups* PCNL group (n = 22) URSL group (n = 31) p Stone free 21 (95.4) 18 (58) Mean treatment time (min) ± ± Postoperative hospital stay (d) 4.7 ± ± Operation-related complications Fever 6 (27.2) 2 (6.5) Pain 8 (36.3) 6 (19.4) Hematuria 12 (54.5) 7 (22.6) Blood loss required transfusion 2 (9.1) 0 Stone upward migration 0 8 (25.8) *Data presented as n (%) or mean ± standard deviation. significantly lower in the URSL group than in the PCNL group. Ten (45.4%) patients in the PCNL group had a proximal ureteral stone combined with renal stones; both the renal and proximal ureteral stones were removed simultaneously during the same session in all but one patient. The EQs for the PCNL and URSL groups were 0.95 and 0.67, respectively. Complications included blood loss requiring transfusion, ascending stones, transient postoperative fever, flank pain, and hematuria (Table 2). In the PCNL group, there were six patients who had a transient postoperative fever, which was controlled with appropriate antibiotics and supportive treatment. Two patients had massive blood loss requiring transfusion. One patient experienced a delayed renal hemorrhage and transarterial embolization of traumatic aneurysm was performed for a pararenal hematoma and massive blood loss. No urinary tract perforation or adjacent organ injury occurred during the procedure. One patient had steinstrasse over the distal ureter after PCNL treatment, but the stone passed spontaneously within 1 week after sufficient hydration and irrigation through the 206 nephrostomy tube. In the URSL group, there were two patients who had episodes of a transient fever, 10 patients who had gross hematuria, and eight patients who had stones showing upward migration during the procedure; seven of these stones were subsequently treated by SWL and one patient underwent PCNL treatment. Upward migrating stone fragments were the leading cause of URSL treatment failure. In one patient, the stone could not be reached due to the tortuosity and angulation of the ureter; therefore, he underwent open ureterolithotomy. There were no major complications in the URSL group. DISCUSSION Long-term impacted ureteral stones may cause interruption of urinary flow and progressive backpressure on the ureter and kidneys, resulting in hydroureteronephrosis. The increased backflow resulting from intrapelvic pressure leads to a decline in renal blood flow with progressive focal ischemia, compression of Kaohsiung J Med Sci April 2008 Vol 24 No 4

4 Comparison of antegrade and retrograde treatment of stones the papillae with a decrease in the glomerular filtration rate, and thinning of the parenchyma due to a loss of nephrons. Significant cortical atrophy will ultimately result in renal function impairment [7]. The optimal management for ureteral stones is still a subject of debate, especially for large, impacted, proximal ureteral stones. SWL has the advantages of an outpatient procedure, minimal requirements for anesthesia, and a low complication rate. However, stone burden, stone composition, and degree of stone impaction are the main variables affecting the stonefree rate after SWL. The impacted stones may be resistant to shock wave disintegration. This phenomenon can be explained by the expansion space theory, in which stones impacted in the ureteral mucosa have no natural expansion space and no water-stone interface, which are critical for calculi fragmentation [8,9]. The high retreatment rate often prohibits SWL as a first-line treatment for a large, impacted, proximal ureteral stone [10,11]. Ureteroscopic lithotripsy was initially introduced as a technique for managing distal ureteral stones and has achieved a high success rate [8]. Because of the improvement in fiberoptics and small caliber semirigid ureteroscopes, we can now directly access the whole ureter without ureteral dilatation. Irrespective of the stone size, Park et al [12] reported an overall stone-free rate of 87.8%. In URSL combined with different kinds of lithotripters, the stone-free rate ranges widely from 35% to 87% for proximal ureteral stones > 15 mm in diameter [9 11]. PCNL can achieve a total stone-free rate from 86% to 98.5% for stone sizes > 15 mm in diameter, which is superior to that with any other treatment [13,14]. In the current study, the stone-free rate was 95.8% in the PCNL group at the 1-month follow-up visit. The other advantage of PCNL is that any associated renal stones can be removed simultaneously. In our series, 10 patients had combined renal stones and we were able to remove both renal and proximal ureteral stones simultaneously in nine of these patients. The complications observed with URSL mainly depend on the surgeon s experiences and skills. The most serious complication is ureteral perforation, which is reported with an incidence of 2 25% [5,11]. Most of these perforations are minor and can be managed by ureteral stents. Some severe perforations may need conversion to an open ureterolithotomy for further ureteral repair. Other complications include ascending stones, postoperative fever, gross hematuria, and ureteral strictures. Upward migration of ureteral stone fragments is the leading cause of incomplete URSL treatment [15,16]. Continuous high-pressure irrigation for obtaining a clear operative visual field may result in an ascending stone. A pneumatic lithotripter is a power lithotripter to fragment all types of stones and is cheaper than the holmium:yttrium-aluminum-garnet (Ho:YAG) laser. However, with the pneumatic lithotripter, there is a greater chance of producing ascending stones. Seven patients in the URSL group needed auxiliary SWL for ascending stones. Dretler [17] designed a stone cone for preventing and minimizing ascending stones during the URSL procedure. However, all ureteral stones in our series were impacted in the ureteral mucosa, where there is no additional space for passing the wire of the stone cone. Complications of bleeding can be managed conservatively in most cases; only about 2 5% of patients need blood transfusion and arterial embolization is rarely required [18]. With preoperative prophylactic broad-spectrum intravenous antibiotics, the present incidence of transient fever was 25% and no patient experienced severe sepsis. All the transient fevers were managed conservatively. Urinary tract perforation, including the renal pelvis or ureter, is seen in some series [18 20]. It is suggested that transfusion and complication rates can be decreased to minimize the nephrostomy tract to the diameter of a sheath that will accept the nephroscope [19]. Using the concept of EQ, we can compare different treatment results with the needs for retreatment and auxiliary procedures. An ideal treatment has an EQ of 1, and if the EQ is < 0.5, the treatment is considered insufficient because every patient requires another treatment or auxiliary procedure to achieve a stone-free state. In our study, the EQs for the PCNL and URSL groups were 0.95 and 0.67, respectively, which is similar to other studies [10,11,21], demonstrating the advantage of the PCNL treatment over URSL therapy for large, proximal ureteral stones. This investigation demonstrated that for large, impacted, proximal ureteral stones > 15 mm in diameter, PCNL met the stone-free rate goals and simultaneously treated coexisting renal stones. URSL has the advantages of less operative time, shorter postoperative hospital stays and fewer postoperative complications, but the main disadvantages are the lower initial stone-free rates and easy stone upward migration. Kaohsiung J Med Sci April 2008 Vol 24 No 4 207

5 Y.S. Juan, J.T. Shen, C.C. Li, et al We suggest that only after discussing and understanding the stone-free success rate, cost-effectiveness, and postoperative complications of these two different treatments with the patients, could we choose the optimal therapeutic modality for large, impacted, proximal ureteral stones. REFERENCES 1. Chaussy C, Schmiedt E, Jocham D, et al. First clinical experience with extracorporeally induced destruction of kidney stones by shock waves. J Urol 1982;127: Chaussy C, Schuller J, Schmiedt E, et al. Extracorporeal shock-wave lithotripsy (ESWL) for treatment of urolithiasis. Urology 1984;23: Bush WH, Gibbons RP, Lewis GP, et al. Impact of extracorporeal shock wave lithotripsy on percutaneous stone procedures. AJR Am J Roentgenol 1986; 147: LeRoy AJ, May GR, Bender CE, et al. Percutaneous nephrostomy for stone removal. Radiology 1984;151: Honeck P, Hacker A, Alken P, et al. Shock wave lithotripsy versus ureteroscopy for distal ureteral calculi: a prospective study. Urol Res 2006;34: Hamano S, Nomura H, Kinsui H, et al. Experience with ureteral stone management in 1,082 patients using semirigid ureteroscopes. Urol Int 2000;65: Hussain M, Ali B, Ahmed S, et al. Prediction of renal function recovery in obstructive renal failure due to stones. J Pak Med Assoc 1997;47: Gurbuz ZG, Gonen M, Fazlioglu A, et al. Ureteroscopy and pneumatic lithotripsy, followed by extracorporeal shock wave lithotripsy for the treatment of distal ureteral stones. Int J Urol 2002;9: Mugiya S, Ozono S, Nagata M, et al. Retrograde endoscopic management of ureteral stones more than 2 cm in size. Urology 2006;67: Wu CF, Shee JJ, Lin WY, et al. Comparison between extracorporeal shock wave lithotripsy and semirigid ureterorenoscope with holmium:yag laser lithotripsy for treating large proximal ureteral stones. J Urol 2004; 172: Lee YH, Tsai JY, Jiaan BP, et al. Prospective randomized trial comparing shock wave lithotripsy and ureteroscopic lithotripsy for management of large upper third ureteral stones. Urology 2006;67: Park H, Park M, Park T. Two-year experience with ureteral stones: extracorporeal shockwave lithotripsy v ureteroscopic manipulation. J Endourol 1998;12: Segura JW, Preminger GM, Assimos DG, et al. Ureteral Stones Clinical Guidelines Panel summary report on the management of ureteral calculi. The American Urological Association. J Urol 1997;158: Goel R, Aron M, Kesarwani PK, et al. Percutaneous antegrade removal of impacted upper-ureteral calculi: still the treatment of choice in developing countries. J Endourol 2005;19: Knispel HH, Klan R, Heicappell R, et al. Pneumatic lithotripsy applied through deflected working channel of miniureteroscope: results in 143 patients. J Endourol 1998;12: Yinghao S, Linhui W, Songxi Q, et al. Treatment of urinary calculi with ureteroscopy and Swiss lithoclast pneumatic lithotripter: report of 150 cases. J Endourol 2000;14: Dretler SP. The stone cone: a new generation of basketry. J Urol 2001;165: Osman M, Wendt-Nordahl G, Heger K, et al. Percutaneous nephrolithotomy with ultrasonography-guided renal access: experience from over 300 cases. BJU Int 2005;96: Maheshwari PN, Oswal AT, Andankar M, et al. Is antegrade ureteroscopy better than retrograde ureteroscopy for impacted large upper ureteral calculi? J Endourol 1999;13: Juan YS, Huang CH, Chuang SM, et al. Colon perforation: a rare complication during percutaneous nephrolithotomy. Kaohsiung J Med Sci 2006;22: Lam JS, Greene TD, Gupta M. Treatment of proximal ureteral calculi: holmium:yag laser ureterolithotripsy versus extracorporeal shock wave lithotripsy. J Urol 2002;167: Kaohsiung J Med Sci April 2008 Vol 24 No 4

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