0022-534 7/90/1432-0263$02.00/0 Vol.
THE JOURNAL OF UROLOGY
Copyright© 1990 by AMERICAN UROLOGICAL ASSOCIATION, INC.
February
in U.S.A.
MANAGEMENT OF THE IMPACTED URETERAL CALCULUS ABRAHAM MORGENTALER,* STEPHENS. BRIDGEt
AND
STEPHEN P. DRETLER:j:
From the Department of Urology, li1a.ssachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
ABSTRACT
The management of 42 impacted ureteral calculi is reviewed. Impacted stones were defined by the inability to pass a guide wire or catheter on initial attempts. Stones were impacted in the upper ureter in 10 patients, mid ureter in 11 and lower ureter in 21. Upper ureteral stones were treated in 8 patients by extracorporeal shock wave lithotripsy after disimpaction by laser or other techniques. Mid ureteral stones were treated by laser alone in 7 patients and by extracorporeal shock wave lithotripsy after disimpaction in 4. Lower stones were treated by laser in 17 patients and ultrasound in 2. Complications included 3 major and 5 minor perforations, and 4 false passages. Treatment was successful without an open operation in 40 of 42 patients (95%). Our current approach to impacted ureteral calculi involves passing a rigid ureteroscope to the stone, with disimpaction performed by laser fragmentation or other dislodgement maneuvers. Proximal stones or large fragments then are treated by extracorporeal shock wave lithotripsy. Mid ureteral stones are treated similarly, unless they are so fragile that in situ fragmentation may be completed easily. Lower ureteral stones are fragmented in situ, with hard fragments extracted by basket. Alternative treatments for impacted calculi at all levels include unstented in situ extracorporeal shock wave lithotripsy, antegrade ureteroscopy and, finally, an operation. (J. Ural., 143: 263266, 1990) Management of the impacted ureteral stone remains a challenge for the urologist. Whereas extracorporeal shock wave lithotripsy (ESWL§) has proved to be effective for renal1· 2 or stented ureteral stones 3 and ureteroscopic techniques have high success rates for stones that can be basketed, fragmented within the ureter or pushed up to the kidney for ESWL,4· 5 the impacted stone frequently does not permit successful application of these techniques. To investigate this matter further, we reviewed our experience with 42 consecutive patients with impacted ureteral stones, defined by the inability to pass a guide wire or stent beyond the stone on initial attempt. We report our findings and our current approach to this problem. MATERIALS AND METHODS
We identified 42 patients with impacted ureteral stones treated between October 1985 and April 1988. An impacted ureteral stone was simply defined as one in which a guide wire or stent could not bypass the stone on initial attempt. The presence of obstruction was not required for inclusion in this study. Steinstrasse were excluded. Impacted stones occurred primarily, or followed ESWL or percutaneous ultrasonic lithotripsy. Patients were treated under general anesthesia. Retrograde contrast studies were performed routinely to evaluate number and location of stones, and anatomy of the ureter. Patients were included in the study if initial attempts to pass a guide wire or catheter failed. Disimpaction techniques included high pressure irrigation via a ureteral catheter, injection of lidocaine jelly in the vicinity of the stone, manual manipulation of the kidney to achieve ureteral straightening6 and straightening of a tortuous ureter by traction on a ureteropelvic junction occlusion balloon catheter below the stone, with a subsequent repeat attempt to pass the guide wire (fig. 1). 7 If attempts to dislodge the stone failed, the ureteral orifice Accepted for publication August 4, 1989. * Current address: Division of Urology, Beth Israel Hospital, Boston, Massachusetts 02215. t Current address: 4060 Fourth Ave., San Diego, California 92103. +Requests for reprints: Massachusetts General Hospital, Fruit St., Boston, Massachusetts 02114. § Dornier Medical Systems, Inc., Marietta, Georgia. 263
was dilated followed by ureteroscopy. The tunnel was dilated by passing a 0.038-inch guide wire to the stone and using an 18F balloon dilator over the guide wire under fluoroscopic control. A rigid ureteroscope then was passed to the stone, with fragmentation performed in situ with the pulsed dye laser or ultrasound. The flexible ureteroscope was used when the rigid ureteroscope could not reach the stone. Electrohydraulic lithotripsy was not used. Fragmentation was continued within the ureter until all fragments were not greater than 1 to 2 mm. Large hard fragments, for example calcium oxalate monohydrate, were basketed under vision and fragmented within the basket, withdrawn or pushed to the kidney. Once the stone was dislodged or fragmented the ureteroscope was advanced through the area of impaction to examine the proximal ureter. Patients with stones of significant size (more than 5 mm.) remaining in the kidney or at the ureteropelvic junction subsequently were treated with ESWL. Two changes occurred in our management with time: 1) placement of a ureteral stent became routine unless a percutaneous nephrostomy tube already was in place and 2) the 7.2F semirigid ureteroscope with laser-delivering capability became available, which became our first choice of instrumentation over the 9.5F (actually ll+F) rigid ureteroscope. This preference was based on the fact that there was no need to dilate the ureteral orifice with the smaller instrument. Furthermore, its small caliber and flexibility enabled us to reach stones that were not possible with the larger ureteroscopes. Large calculi (greater than 1.5 cm.) were approached with the ultrasonic sonotrode, which required an llF sheath (actually 13+ F). RESULTS
We evaluated 31 men and 11 women with impacted ureteral calculi. Mean patient age was 58 years, with a range of 30 to 78 years. Stones averaged 11 mm. long and 7 mm. wide as measured on plain abdominal radiography. The largest stone measured 22 x 11 mm. Stone composition was available in 20 patients and included calcium monohydrate in 15 (75%), struvite in 1, calcium phosphate in 1, uric acid in 2 and carbonate apatite in 1. The majority of unrecovered stones were believed to be calcium oxalate dihydrate, since these crumbled into tiny particles at fragmentation and were unable to be recovered for
264
MORGENTALER, BRIDGE AND DRETLER
FIG. 2. Impacted stone in tortuous ureter. A, unable to place guide wire by stone. B, retrograde ureterogram shows size of stone and degree of impaction. C, ureteropelvic junction occlusion balloon below stone left inflated to allow dilatation of ureter and fluid-stone interface for in situ ESWL. ESWL resulted in complete fragmentation. TABLE 2.
Results of laser fragmentation No.
FIG. 1. Impacted ureteral stone. A, retrograde ureterogram demonstrates tortuous ureter and inability to bypass stone (arrow). B, ureteropelvic junction occlusion balloon (arrowhead) inflated with 0.6 cc by tuberculin syringe just below site of impaction (arrow). Note cylindrical shape of inflated balloon. C, traction on ureteropelvic junction occlusion balloon (arrowhead) straightens ureter. Arrow indicates stone. D, guide wire then bypasses stone (arrow). TABLE
1. Treatment by stone location
Laser fragmentation Complete Partial: Additional treatment:* ESWL Stone basket extraction Repeat ureteroscopy/fragmentation Stone dislodged to bladder via percutaneous nephrostomy Surgery
32
18 14 8 4 3
1
* Several patients underwent more than 1 secondary procedure. No.
Upper ureter (Ll-L3): Laser followed by ESWL ESWL after ureteroscopic stenting ESWL unstented ESWL after stone displaced Laser Ureterolithotomy Mid ureter (L3-Sl): Laser Laser followed by ESWL ESWL after stone displaced ESWL after occlusion balloon for 24 hrs. Lower ureter (Sl-tunnel): Laser Ultrasound Laser followed by ESWL Laser followed by ureterolithotomy
10 4 2 1 1 1 1 11 7 2 1 1 21 17 2 1 1
analysis. Duration of stone impaction was known in 21 patients (50%): less than 2 weeks in 1, 2 to 4 weeks in 4, 4 to 8 weeks in 1 and greater than 8 weeks in 15 (71 %). Seven patients were treated for impacted stones after failed ESWL. Eleven patients underwent some form of stone manipulation elsewhere and were referred for further treatment. Failed manipulations included percutaneous ultrasonic lithotripsy (1 patient), attempts at stent, catheter or guide wire placement (6), stone basketing (3) and an unsuccessful attempt to dislodge a stone to the renal pelvis with the ureteroscope (1).
Ten patients had stones in the upper ureter (Ll to L3), 11 in the mid ureter (L3 to 81) and 21 in the distal ureter. Treatment by stone location is indicated in table 1.
Initial treatment for upper ureteral stones was laser fragmentation in 5 patients, ESWL in 4 and ureterolithotomy in 1. Of the 5 stones treated with the laser 4 underwent additional treatment with ESWL for residual or displaced fragments. Ureterolithotomy and segmental ureterectomy were performed on a patient with a severe ureteral stricture that could not be treated adequately at ureteroscopy. Mid ureteral stones (11 patients) were treated initially by laser in 9 and ESWL in 2. One of these patients had an occlusion balloon inflated below the stone 24 hours before ESWL after attempts to visualize the stone endoscopically were unsuccessful. The occlusion balloon allowed the ureter to distend, facilitating ESWL treatment (fig. 2). One patient underwent ureteroscopic laser fragmentation via percutaneous nephrostomy. Two stones disimpacted by partial laser fragmentation subsequently were treated by ESWL. Half of the impacted stones occurred in the lower ureter (21 patients). The laser was used in 19 patients and ultrasound in 2 with large stones. One patient underwent subsequent ESWL. Two patients had repeat ureteroscopic stone fragmentation within 1 month and 1 underwent ureterolithotomy after partial laser fragmentation complicated by a ureteral perforation. Over-all, 40 of 42 patients (95%) were treated successfully by endourological techniques alone or in combination with ESWL. Laser fragmentation was performed in 32 patients: 18 (56%) had complete and 14 had partial fragmentation (table 2). Partial fragmentation was followed by 1 or more of the following procedures: ESWL (8), basketing (4), repeat ureteroscopy with laser or ultrasound fragmentation (3), manipulation of frag-
IMPACTED URETERAL CALCULI
ments into the bladder via percutaneous nephrostomy (1) and open ureterolithotomy (1). Complications consisted of major perforations in 3 patients, creation of false passages in 4 and minor perforations with wire or laser fiber in 5. Major perforations were treated as follows. One patient had perforation by the ureteroscope and underwent surgical correction. One patient had stent perforation of the ureter immediately before ESWL for a large impacted ureteropelvic junction stone. After ESWL, the remaining large impacted calculus was laser fragmented with visualization of the perforation site. The stone was fragmented enough to be dislodged to the kidney. A stent was placed and the patient subsequently underwent repeat ESWL without further problems. One patient underwent incision of a ureteral stricture during ureteroscopy, resulting in a perforation. Laser fragmentation and stenting were performed without problem. No other complications required specific intervention other than routine stenting. Strictures developed in 2 patients to our knowledge, both recognized by residual stone fragments causing clinical symptoms. One stricture occurred after a false passage was created by ureteroscopy during treatment of a lower ureteral stone with laser, while 1 patient had a failed stone extraction elsewhere, then underwent ureteroscopy and laser fragmentation of a soft stone without stent placement. Since followup studies generally were performed by the referring physician, complete data on stricture formation and clearance of fragments are not available. DISCUSSION
The challenge of treating impacted ureteral calculi stems from the restrictions placed on the otherwise highly effective modern urological armamentarium. The decreased efficacy of ESWL for the unstented ureteral stone is well documented, 3• 4 presumably because of a lack of an adequate expansion chamber. This should apply particularly to the impacted stone. During ureteroscopy, the inability to pass a guide wire by the stone reduces the safety margin and increases the possibility of bleeding, perforation or creation of a false passage. Basketing a stone is difficult unless the basket can be passed proximally. The initial objective then should be to disimpact the stone so that standard techniques may be applied, such as in situ fragmentation with laser, ultrasound or electrohydraulic lithotripsy, basketing the entire stone or its fragments, or pushing the stone up to the kidney where it can be treated by ESWL. Disimpaction is difficult because of the characteristic surrounding edema, which causes narrowing of the lumen above and below the calculus. The edematous ureter also is prone to perforation with even gentle technique. The area just at the point of impaction is the point of exit for wires, stents and thin ureteroscopes. A variety of disimpaction maneuvers exist, including high pressure irrigation, injection of lubricant or lidocaine jelly in the vicinity of the stone, carbon dioxide flushing with a venting nephrostomy tube,8 pushing the stone with a catheter or ureteroscope, or placing an occlusion balloon below the stone to allow for hydrodilation of the ureter. 9 Characteristically, long-term impaction causes ureteral tortuosity above and below the stone. Straightening of the ureter will assist passage of a guide wire. One method is to place traction on an occlusion balloon so that the ureter is straightened and a guide wire may be passed (fig. 1). Also, one may place an angiographic catheter to the level of the stone and pass the guide wire through it, achieving improved purchase and less bending of the guide wire as it emerges from the catheter. Evans and associates compared saline, lidocaine jelly and lubricant jelly injections in blind fashion to manipulate impacted stones before ESWL, and found saline irrigation to be best, although they noted that the difference was not statistically significant. 10 The result may have occurred because higher pressures could be achieved with saline irrigation. Saline irrigation was successful in 3 of our
265
patients. One stone also was dislodged with the ureteroscope and 1 proximal stone was successfully fragmented by ESWL after placement of an occlusion balloon below it (fig. 2). However, we did not attempt all of these disimpaction techniques with each case. Fewer options are available when the stone cannot be displaced. Our initial choice was to perform ureteroscopy with in situ fragmentation. The primary modality was laser in 32 patients and ultrasound in 2. Ultrasound was reserved for the larger, harder stones, since it is more effective than the laser for calcium oxalate monohydrate. The need for ultrasound can be judged preoperatively by the radiodensity of the calculus on a plain radiograph, which often correlates with stone fragility. 11 ESWL was used as an additional procedure in 7 patients in whom the laser was used for disimpaction. This use was primarily for proximal or hard stones that could be pushed to the kidney after partial fragmentation and disimpaction. Hard stones in the lower or mid ureter were fragmented partially and withdrawn with the basket. ESWL had a major role in the treatment of upper ureteral calculi and the strategy of our ureteroscopic techniques was adapted to take advantage of the high success of this modality with stented stones. In situ ureteroscopic fragmentation was preferred for most mid ureteral and all impacted lower ureteral stones, with ESWL reserved for instances when the stone migrated to the kidney. The laser appears to be an ideal modality for the treatment of impacted ureteral stones. The 250 µ. fiber is small and flexible enough to pass through the smallest available ureteroscopes as well as the flexible instruments yet it is capable of delivering enough energy to fragment most stones within a reasonable operating time. 12 The laser delivers energy at 504 nm. wavelength, which is absorbed by calculi but not hemoglobin. Therefore, the ureter is not harmed by direct laser energy itself, unlike ultrasound or electrohydraulic lithotripsy. The main complication attributable to the laser has been minor perforations caused by the sharp thin fiber. The ability to use smaller ureteroscopes with the laser fiber is a distinct advan tage, requiring infrequent ureteral dilation, and access to stones beyond the reach of larger instruments. Flexible steerable ureteroscopes are available in small sizes (for example 9.8F). However in our experience with current flexible instruments the laser fiber often exited the tip with difficulty, ureteral dilation was required and there was insufficient torque and control at the tip. We prefer the 7.2F semirigid ureteroscope for the male lower ureter and all locations in the female ureter. However, when the ureter is so tortuous as to make rigid instrumentation difficult, the flexible steerable ureteroscope is a good choice (fig. 3). Once the stone is visualized fragmentation can be initiated. Soft calcium oxalate dihydrate stones can be fragmented easily to particles 1 to 2 mm. in size. However, the black, hard calcium monohydrate stones usually require more effort. Frequently, we have encountered stones with an outer shell of yellow calcium oxalate dihydrate and an inner core of black calcium oxalate monohydrate. In these cases we chip off the outer soft shell and trap the stone in a basket for further fragmentation or, if small enough, the remaining hard fragments are removed with the basket. Large hard ureteral stones in the upper ureter are treated best by disimpaction and displacement to the kidney, where they then can be treated by ESWL. Postoperative stenting was not routine in the early experience but with the advent of stents with strings we later stented all patients when possible, unless there was a pre-existing percutaneous nephrostomy tube. One of our 2 patients with a stricture did not receive a stent. Stents permit less painful passage of stone fragments and prevent ureteral obstruction secondary to edema. To avoid difficulty in placing a stent from below the stone due to false passages or mucosal flaps in ureters that have undergone significant manipulation, we frequently use a stent that can be placed via the ureteroscope directly into the renal pelvis.
266
MORGENTALER, BRIDGE AND DRETLER
FIG. 3. Flexible ureteroscopy for impacted stones. A, tortuous ureter required flexible steerable ureteroscope for stone treatment. B, dislodgement of stone to kidney was followed by advancement of instrument to kidney and completion of fragmentation.
What options are available if ureteroscopic access to the stone is impossible? Unstented ESWL in situ of impacted ureteral stones is a noninvasive therapy that may succeed, even though the success rate is inferior to the stented situation. Our impression is that stones that appear radiographically fragile are more likely to be treated successfully by ESWL in situ. Fragmentation may be improved if a catheter is placed to the level of the stone and saline is injected during ESWL to create a fluid-tissue interface, which thereby increases the effectiveness of the shock wave. This treatment was attempted in 2 cases when no other options were available, resulting in 1 success and 1 failure. Alternatively, an occlusion balloon catheter may be inflated below the stone with subsequent ESWL in a hydrostatically dilated ureter. Balloon dilation must be performed under fluoroscopic control to ensure that the balloon maintains a cylindrical form consistent with an intact ureter. Another option is endoscopic treatment from above the stone via percutaneous nephrostomy, which was successful in 1 of our patients with a pre-existing percutaneous nephrostomy tube. Finally, ureterolithotomy may be the most expedient treatment in certain circumstances. Two of our patients underwent this procedure: 1 to repair a perforation caused by the ureteroscope, while 1 had a stone lying above a severe ureteral stricture that made surgical treatment preferable, since the stone and stricture could be treated properly. We believe that large (greater than 1.5 cm.), radiodense, impacted upper ureteral calculi that are unstentable and cannot be reached with a flexible or rigid ureteroscope are treated best in most hands by ureterolithotomy rather than by percutaneous techniques. Our current approach to impacted ureteral stones that have failed nonureteroscopic disimpaction techniques is presented. A guide wire is passed to the stone, followed by the rigid 9.5 or 7.2F ureteroscope, with dilation performed as necessary. If unable to reach the stone with rigid instruments we use the flexible steerable ureteroscope. Stones impacted at the uretero-
pelvic junction or in the proximal ureter are disimpacted with the laser or other techniques and displaced to the renal pelvis for subsequent ESWL. Mid ureteral stones are either disimpacted and stented for ESWL, or completely fragmented in situ depending on the fragility. Lower stones are treated preferentially by in situ fragmentation. Fragmentation in situ is performed by laser, with ultrasound reserved for large or hard stones. Should these techniques fail ESWL in situ, antegrade ureteroscopy via percutaneous nephrostomy or ureterolithotomy is performed. It should be noted that in situ ESWL for ureteral calculi is gaining in popularity, with many investigators reporting success in approximately 80% of the cases. However, it is unclear whether long-impacted stones were included in these series. Our own initial experience suggested that ESWL failed in 40% of the nonstented calculi4 and in retrospect it appears that impacted fragile stones fragmented while hard ones did not. Although data to prove this observation are lacking, we would sooner recommend in situ ESWL for a small impacted fragile-appearing stone than for a large hard calculus. The impacted ureteral stone represents a challenging therapeutic problem. Successful therapy may be achieved with minimum morbidity by a number of endourological methods. An operation should be reserved for the large, radiodense, severely impacted upper ureteral calculus or the stone for which other manipulative efforts have failed. REFERENCES 1. Chaussy, C., Brendel, W. and Schmiedt, E.: Extracorporeally induced destruction of kidney stones by shock waves. Lancet, 2: 1265, 1980. 2. Drach, G. W., Dretler, S., Fair, W., Finlayson, B., Gillenwater, J., Griffith, D., Lingeman, J. and Newman, D.: Report of the United States cooperative study of extracorporeal shock wave lithotripsy. J. Urol., 135: 1127, 1986. 3. Lingeman, J. E., Shirrell, W. L., Newman, D. M., Mosbaugh, P. G., Steele, R. E. and Woods, J. R.: Management of upper ureteral calculi with extracorporeal shock wave lithotripsy. J. Urol., 138: 720, 1987. 4. Dretler, S. P., Keating, M. A. and Riley, J.: An algorithm for the management of ureteral calculi. J. Urol., 136: 1190, 1986. 5. Blute, M. L., Segura, J. W. and Patterson, D. E.: Ureteroscopy. J. Urol., 139: 510, 1988. 6. Lingeman, J. E.: Mertz maneuver for catheterizing the tortuous ureter. Endourology, 2(2): 16, 1987. 7. Clayman, R. V.: Catheterizing the tortuous ureter. Endourology, 2(4): 14, 1987. 8. Hulbert, J. C., Reddy, P. K., Hunter, D. W., Young, A. T., Castaneda-Zuniga, W. R., Amplatz, K. and Lange, P. H.: Percutaneous management of ureteral calculi facilitated by retrograde flushing with carbon dioxide or diluted radiopaque dye. J. Urol., 134: 29, 1985. 9. Beckmann, C. F. and Roth, R. A.: Use of retrograde occlusion balloon catheters in percutaneous removal of renal calculi. Urology, 25: 277, 1985. 10. Evans, R. J., Wingfield, D. D., Morollo, B. A. and Jenkins, A. D.: Ureteral stone manipulation before extracorporeal shock wave lithotripsy. J. Urol., 139: 33, 1988. 11. Dretler, S. P.: Stone fragility-a new therapeutic distinction. J. Urol., 139: 1124, 1988. 12. Dretler, S. P., Watson, G., Parrish, J. A. and Murray, S.: Pulsed dye laser fragmentation of ureteral calculi: initial clinical experience. J. Urol., 137: 386, 1987.
THE JOURNAL OF UROLOGY
Copyright© 1990 by AMERICAN UROLOGICAL ASSOCIATION, INC.
February
in U.S.A.
MANAGEMENT OF THE IMPACTED URETERAL CALCULUS ABRAHAM MORGENTALER,* STEPHENS. BRIDGEt
AND
STEPHEN P. DRETLER:j:
From the Department of Urology, li1a.ssachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
ABSTRACT
The management of 42 impacted ureteral calculi is reviewed. Impacted stones were defined by the inability to pass a guide wire or catheter on initial attempts. Stones were impacted in the upper ureter in 10 patients, mid ureter in 11 and lower ureter in 21. Upper ureteral stones were treated in 8 patients by extracorporeal shock wave lithotripsy after disimpaction by laser or other techniques. Mid ureteral stones were treated by laser alone in 7 patients and by extracorporeal shock wave lithotripsy after disimpaction in 4. Lower stones were treated by laser in 17 patients and ultrasound in 2. Complications included 3 major and 5 minor perforations, and 4 false passages. Treatment was successful without an open operation in 40 of 42 patients (95%). Our current approach to impacted ureteral calculi involves passing a rigid ureteroscope to the stone, with disimpaction performed by laser fragmentation or other dislodgement maneuvers. Proximal stones or large fragments then are treated by extracorporeal shock wave lithotripsy. Mid ureteral stones are treated similarly, unless they are so fragile that in situ fragmentation may be completed easily. Lower ureteral stones are fragmented in situ, with hard fragments extracted by basket. Alternative treatments for impacted calculi at all levels include unstented in situ extracorporeal shock wave lithotripsy, antegrade ureteroscopy and, finally, an operation. (J. Ural., 143: 263266, 1990) Management of the impacted ureteral stone remains a challenge for the urologist. Whereas extracorporeal shock wave lithotripsy (ESWL§) has proved to be effective for renal1· 2 or stented ureteral stones 3 and ureteroscopic techniques have high success rates for stones that can be basketed, fragmented within the ureter or pushed up to the kidney for ESWL,4· 5 the impacted stone frequently does not permit successful application of these techniques. To investigate this matter further, we reviewed our experience with 42 consecutive patients with impacted ureteral stones, defined by the inability to pass a guide wire or stent beyond the stone on initial attempt. We report our findings and our current approach to this problem. MATERIALS AND METHODS
We identified 42 patients with impacted ureteral stones treated between October 1985 and April 1988. An impacted ureteral stone was simply defined as one in which a guide wire or stent could not bypass the stone on initial attempt. The presence of obstruction was not required for inclusion in this study. Steinstrasse were excluded. Impacted stones occurred primarily, or followed ESWL or percutaneous ultrasonic lithotripsy. Patients were treated under general anesthesia. Retrograde contrast studies were performed routinely to evaluate number and location of stones, and anatomy of the ureter. Patients were included in the study if initial attempts to pass a guide wire or catheter failed. Disimpaction techniques included high pressure irrigation via a ureteral catheter, injection of lidocaine jelly in the vicinity of the stone, manual manipulation of the kidney to achieve ureteral straightening6 and straightening of a tortuous ureter by traction on a ureteropelvic junction occlusion balloon catheter below the stone, with a subsequent repeat attempt to pass the guide wire (fig. 1). 7 If attempts to dislodge the stone failed, the ureteral orifice Accepted for publication August 4, 1989. * Current address: Division of Urology, Beth Israel Hospital, Boston, Massachusetts 02215. t Current address: 4060 Fourth Ave., San Diego, California 92103. +Requests for reprints: Massachusetts General Hospital, Fruit St., Boston, Massachusetts 02114. § Dornier Medical Systems, Inc., Marietta, Georgia. 263
was dilated followed by ureteroscopy. The tunnel was dilated by passing a 0.038-inch guide wire to the stone and using an 18F balloon dilator over the guide wire under fluoroscopic control. A rigid ureteroscope then was passed to the stone, with fragmentation performed in situ with the pulsed dye laser or ultrasound. The flexible ureteroscope was used when the rigid ureteroscope could not reach the stone. Electrohydraulic lithotripsy was not used. Fragmentation was continued within the ureter until all fragments were not greater than 1 to 2 mm. Large hard fragments, for example calcium oxalate monohydrate, were basketed under vision and fragmented within the basket, withdrawn or pushed to the kidney. Once the stone was dislodged or fragmented the ureteroscope was advanced through the area of impaction to examine the proximal ureter. Patients with stones of significant size (more than 5 mm.) remaining in the kidney or at the ureteropelvic junction subsequently were treated with ESWL. Two changes occurred in our management with time: 1) placement of a ureteral stent became routine unless a percutaneous nephrostomy tube already was in place and 2) the 7.2F semirigid ureteroscope with laser-delivering capability became available, which became our first choice of instrumentation over the 9.5F (actually ll+F) rigid ureteroscope. This preference was based on the fact that there was no need to dilate the ureteral orifice with the smaller instrument. Furthermore, its small caliber and flexibility enabled us to reach stones that were not possible with the larger ureteroscopes. Large calculi (greater than 1.5 cm.) were approached with the ultrasonic sonotrode, which required an llF sheath (actually 13+ F). RESULTS
We evaluated 31 men and 11 women with impacted ureteral calculi. Mean patient age was 58 years, with a range of 30 to 78 years. Stones averaged 11 mm. long and 7 mm. wide as measured on plain abdominal radiography. The largest stone measured 22 x 11 mm. Stone composition was available in 20 patients and included calcium monohydrate in 15 (75%), struvite in 1, calcium phosphate in 1, uric acid in 2 and carbonate apatite in 1. The majority of unrecovered stones were believed to be calcium oxalate dihydrate, since these crumbled into tiny particles at fragmentation and were unable to be recovered for
264
MORGENTALER, BRIDGE AND DRETLER
FIG. 2. Impacted stone in tortuous ureter. A, unable to place guide wire by stone. B, retrograde ureterogram shows size of stone and degree of impaction. C, ureteropelvic junction occlusion balloon below stone left inflated to allow dilatation of ureter and fluid-stone interface for in situ ESWL. ESWL resulted in complete fragmentation. TABLE 2.
Results of laser fragmentation No.
FIG. 1. Impacted ureteral stone. A, retrograde ureterogram demonstrates tortuous ureter and inability to bypass stone (arrow). B, ureteropelvic junction occlusion balloon (arrowhead) inflated with 0.6 cc by tuberculin syringe just below site of impaction (arrow). Note cylindrical shape of inflated balloon. C, traction on ureteropelvic junction occlusion balloon (arrowhead) straightens ureter. Arrow indicates stone. D, guide wire then bypasses stone (arrow). TABLE
1. Treatment by stone location
Laser fragmentation Complete Partial: Additional treatment:* ESWL Stone basket extraction Repeat ureteroscopy/fragmentation Stone dislodged to bladder via percutaneous nephrostomy Surgery
32
18 14 8 4 3
1
* Several patients underwent more than 1 secondary procedure. No.
Upper ureter (Ll-L3): Laser followed by ESWL ESWL after ureteroscopic stenting ESWL unstented ESWL after stone displaced Laser Ureterolithotomy Mid ureter (L3-Sl): Laser Laser followed by ESWL ESWL after stone displaced ESWL after occlusion balloon for 24 hrs. Lower ureter (Sl-tunnel): Laser Ultrasound Laser followed by ESWL Laser followed by ureterolithotomy
10 4 2 1 1 1 1 11 7 2 1 1 21 17 2 1 1
analysis. Duration of stone impaction was known in 21 patients (50%): less than 2 weeks in 1, 2 to 4 weeks in 4, 4 to 8 weeks in 1 and greater than 8 weeks in 15 (71 %). Seven patients were treated for impacted stones after failed ESWL. Eleven patients underwent some form of stone manipulation elsewhere and were referred for further treatment. Failed manipulations included percutaneous ultrasonic lithotripsy (1 patient), attempts at stent, catheter or guide wire placement (6), stone basketing (3) and an unsuccessful attempt to dislodge a stone to the renal pelvis with the ureteroscope (1).
Ten patients had stones in the upper ureter (Ll to L3), 11 in the mid ureter (L3 to 81) and 21 in the distal ureter. Treatment by stone location is indicated in table 1.
Initial treatment for upper ureteral stones was laser fragmentation in 5 patients, ESWL in 4 and ureterolithotomy in 1. Of the 5 stones treated with the laser 4 underwent additional treatment with ESWL for residual or displaced fragments. Ureterolithotomy and segmental ureterectomy were performed on a patient with a severe ureteral stricture that could not be treated adequately at ureteroscopy. Mid ureteral stones (11 patients) were treated initially by laser in 9 and ESWL in 2. One of these patients had an occlusion balloon inflated below the stone 24 hours before ESWL after attempts to visualize the stone endoscopically were unsuccessful. The occlusion balloon allowed the ureter to distend, facilitating ESWL treatment (fig. 2). One patient underwent ureteroscopic laser fragmentation via percutaneous nephrostomy. Two stones disimpacted by partial laser fragmentation subsequently were treated by ESWL. Half of the impacted stones occurred in the lower ureter (21 patients). The laser was used in 19 patients and ultrasound in 2 with large stones. One patient underwent subsequent ESWL. Two patients had repeat ureteroscopic stone fragmentation within 1 month and 1 underwent ureterolithotomy after partial laser fragmentation complicated by a ureteral perforation. Over-all, 40 of 42 patients (95%) were treated successfully by endourological techniques alone or in combination with ESWL. Laser fragmentation was performed in 32 patients: 18 (56%) had complete and 14 had partial fragmentation (table 2). Partial fragmentation was followed by 1 or more of the following procedures: ESWL (8), basketing (4), repeat ureteroscopy with laser or ultrasound fragmentation (3), manipulation of frag-
IMPACTED URETERAL CALCULI
ments into the bladder via percutaneous nephrostomy (1) and open ureterolithotomy (1). Complications consisted of major perforations in 3 patients, creation of false passages in 4 and minor perforations with wire or laser fiber in 5. Major perforations were treated as follows. One patient had perforation by the ureteroscope and underwent surgical correction. One patient had stent perforation of the ureter immediately before ESWL for a large impacted ureteropelvic junction stone. After ESWL, the remaining large impacted calculus was laser fragmented with visualization of the perforation site. The stone was fragmented enough to be dislodged to the kidney. A stent was placed and the patient subsequently underwent repeat ESWL without further problems. One patient underwent incision of a ureteral stricture during ureteroscopy, resulting in a perforation. Laser fragmentation and stenting were performed without problem. No other complications required specific intervention other than routine stenting. Strictures developed in 2 patients to our knowledge, both recognized by residual stone fragments causing clinical symptoms. One stricture occurred after a false passage was created by ureteroscopy during treatment of a lower ureteral stone with laser, while 1 patient had a failed stone extraction elsewhere, then underwent ureteroscopy and laser fragmentation of a soft stone without stent placement. Since followup studies generally were performed by the referring physician, complete data on stricture formation and clearance of fragments are not available. DISCUSSION
The challenge of treating impacted ureteral calculi stems from the restrictions placed on the otherwise highly effective modern urological armamentarium. The decreased efficacy of ESWL for the unstented ureteral stone is well documented, 3• 4 presumably because of a lack of an adequate expansion chamber. This should apply particularly to the impacted stone. During ureteroscopy, the inability to pass a guide wire by the stone reduces the safety margin and increases the possibility of bleeding, perforation or creation of a false passage. Basketing a stone is difficult unless the basket can be passed proximally. The initial objective then should be to disimpact the stone so that standard techniques may be applied, such as in situ fragmentation with laser, ultrasound or electrohydraulic lithotripsy, basketing the entire stone or its fragments, or pushing the stone up to the kidney where it can be treated by ESWL. Disimpaction is difficult because of the characteristic surrounding edema, which causes narrowing of the lumen above and below the calculus. The edematous ureter also is prone to perforation with even gentle technique. The area just at the point of impaction is the point of exit for wires, stents and thin ureteroscopes. A variety of disimpaction maneuvers exist, including high pressure irrigation, injection of lubricant or lidocaine jelly in the vicinity of the stone, carbon dioxide flushing with a venting nephrostomy tube,8 pushing the stone with a catheter or ureteroscope, or placing an occlusion balloon below the stone to allow for hydrodilation of the ureter. 9 Characteristically, long-term impaction causes ureteral tortuosity above and below the stone. Straightening of the ureter will assist passage of a guide wire. One method is to place traction on an occlusion balloon so that the ureter is straightened and a guide wire may be passed (fig. 1). Also, one may place an angiographic catheter to the level of the stone and pass the guide wire through it, achieving improved purchase and less bending of the guide wire as it emerges from the catheter. Evans and associates compared saline, lidocaine jelly and lubricant jelly injections in blind fashion to manipulate impacted stones before ESWL, and found saline irrigation to be best, although they noted that the difference was not statistically significant. 10 The result may have occurred because higher pressures could be achieved with saline irrigation. Saline irrigation was successful in 3 of our
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patients. One stone also was dislodged with the ureteroscope and 1 proximal stone was successfully fragmented by ESWL after placement of an occlusion balloon below it (fig. 2). However, we did not attempt all of these disimpaction techniques with each case. Fewer options are available when the stone cannot be displaced. Our initial choice was to perform ureteroscopy with in situ fragmentation. The primary modality was laser in 32 patients and ultrasound in 2. Ultrasound was reserved for the larger, harder stones, since it is more effective than the laser for calcium oxalate monohydrate. The need for ultrasound can be judged preoperatively by the radiodensity of the calculus on a plain radiograph, which often correlates with stone fragility. 11 ESWL was used as an additional procedure in 7 patients in whom the laser was used for disimpaction. This use was primarily for proximal or hard stones that could be pushed to the kidney after partial fragmentation and disimpaction. Hard stones in the lower or mid ureter were fragmented partially and withdrawn with the basket. ESWL had a major role in the treatment of upper ureteral calculi and the strategy of our ureteroscopic techniques was adapted to take advantage of the high success of this modality with stented stones. In situ ureteroscopic fragmentation was preferred for most mid ureteral and all impacted lower ureteral stones, with ESWL reserved for instances when the stone migrated to the kidney. The laser appears to be an ideal modality for the treatment of impacted ureteral stones. The 250 µ. fiber is small and flexible enough to pass through the smallest available ureteroscopes as well as the flexible instruments yet it is capable of delivering enough energy to fragment most stones within a reasonable operating time. 12 The laser delivers energy at 504 nm. wavelength, which is absorbed by calculi but not hemoglobin. Therefore, the ureter is not harmed by direct laser energy itself, unlike ultrasound or electrohydraulic lithotripsy. The main complication attributable to the laser has been minor perforations caused by the sharp thin fiber. The ability to use smaller ureteroscopes with the laser fiber is a distinct advan tage, requiring infrequent ureteral dilation, and access to stones beyond the reach of larger instruments. Flexible steerable ureteroscopes are available in small sizes (for example 9.8F). However in our experience with current flexible instruments the laser fiber often exited the tip with difficulty, ureteral dilation was required and there was insufficient torque and control at the tip. We prefer the 7.2F semirigid ureteroscope for the male lower ureter and all locations in the female ureter. However, when the ureter is so tortuous as to make rigid instrumentation difficult, the flexible steerable ureteroscope is a good choice (fig. 3). Once the stone is visualized fragmentation can be initiated. Soft calcium oxalate dihydrate stones can be fragmented easily to particles 1 to 2 mm. in size. However, the black, hard calcium monohydrate stones usually require more effort. Frequently, we have encountered stones with an outer shell of yellow calcium oxalate dihydrate and an inner core of black calcium oxalate monohydrate. In these cases we chip off the outer soft shell and trap the stone in a basket for further fragmentation or, if small enough, the remaining hard fragments are removed with the basket. Large hard ureteral stones in the upper ureter are treated best by disimpaction and displacement to the kidney, where they then can be treated by ESWL. Postoperative stenting was not routine in the early experience but with the advent of stents with strings we later stented all patients when possible, unless there was a pre-existing percutaneous nephrostomy tube. One of our 2 patients with a stricture did not receive a stent. Stents permit less painful passage of stone fragments and prevent ureteral obstruction secondary to edema. To avoid difficulty in placing a stent from below the stone due to false passages or mucosal flaps in ureters that have undergone significant manipulation, we frequently use a stent that can be placed via the ureteroscope directly into the renal pelvis.
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MORGENTALER, BRIDGE AND DRETLER
FIG. 3. Flexible ureteroscopy for impacted stones. A, tortuous ureter required flexible steerable ureteroscope for stone treatment. B, dislodgement of stone to kidney was followed by advancement of instrument to kidney and completion of fragmentation.
What options are available if ureteroscopic access to the stone is impossible? Unstented ESWL in situ of impacted ureteral stones is a noninvasive therapy that may succeed, even though the success rate is inferior to the stented situation. Our impression is that stones that appear radiographically fragile are more likely to be treated successfully by ESWL in situ. Fragmentation may be improved if a catheter is placed to the level of the stone and saline is injected during ESWL to create a fluid-tissue interface, which thereby increases the effectiveness of the shock wave. This treatment was attempted in 2 cases when no other options were available, resulting in 1 success and 1 failure. Alternatively, an occlusion balloon catheter may be inflated below the stone with subsequent ESWL in a hydrostatically dilated ureter. Balloon dilation must be performed under fluoroscopic control to ensure that the balloon maintains a cylindrical form consistent with an intact ureter. Another option is endoscopic treatment from above the stone via percutaneous nephrostomy, which was successful in 1 of our patients with a pre-existing percutaneous nephrostomy tube. Finally, ureterolithotomy may be the most expedient treatment in certain circumstances. Two of our patients underwent this procedure: 1 to repair a perforation caused by the ureteroscope, while 1 had a stone lying above a severe ureteral stricture that made surgical treatment preferable, since the stone and stricture could be treated properly. We believe that large (greater than 1.5 cm.), radiodense, impacted upper ureteral calculi that are unstentable and cannot be reached with a flexible or rigid ureteroscope are treated best in most hands by ureterolithotomy rather than by percutaneous techniques. Our current approach to impacted ureteral stones that have failed nonureteroscopic disimpaction techniques is presented. A guide wire is passed to the stone, followed by the rigid 9.5 or 7.2F ureteroscope, with dilation performed as necessary. If unable to reach the stone with rigid instruments we use the flexible steerable ureteroscope. Stones impacted at the uretero-
pelvic junction or in the proximal ureter are disimpacted with the laser or other techniques and displaced to the renal pelvis for subsequent ESWL. Mid ureteral stones are either disimpacted and stented for ESWL, or completely fragmented in situ depending on the fragility. Lower stones are treated preferentially by in situ fragmentation. Fragmentation in situ is performed by laser, with ultrasound reserved for large or hard stones. Should these techniques fail ESWL in situ, antegrade ureteroscopy via percutaneous nephrostomy or ureterolithotomy is performed. It should be noted that in situ ESWL for ureteral calculi is gaining in popularity, with many investigators reporting success in approximately 80% of the cases. However, it is unclear whether long-impacted stones were included in these series. Our own initial experience suggested that ESWL failed in 40% of the nonstented calculi4 and in retrospect it appears that impacted fragile stones fragmented while hard ones did not. Although data to prove this observation are lacking, we would sooner recommend in situ ESWL for a small impacted fragile-appearing stone than for a large hard calculus. The impacted ureteral stone represents a challenging therapeutic problem. Successful therapy may be achieved with minimum morbidity by a number of endourological methods. An operation should be reserved for the large, radiodense, severely impacted upper ureteral calculus or the stone for which other manipulative efforts have failed. REFERENCES 1. Chaussy, C., Brendel, W. and Schmiedt, E.: Extracorporeally induced destruction of kidney stones by shock waves. Lancet, 2: 1265, 1980. 2. Drach, G. W., Dretler, S., Fair, W., Finlayson, B., Gillenwater, J., Griffith, D., Lingeman, J. and Newman, D.: Report of the United States cooperative study of extracorporeal shock wave lithotripsy. J. Urol., 135: 1127, 1986. 3. Lingeman, J. E., Shirrell, W. L., Newman, D. M., Mosbaugh, P. G., Steele, R. E. and Woods, J. R.: Management of upper ureteral calculi with extracorporeal shock wave lithotripsy. J. Urol., 138: 720, 1987. 4. Dretler, S. P., Keating, M. A. and Riley, J.: An algorithm for the management of ureteral calculi. J. Urol., 136: 1190, 1986. 5. Blute, M. L., Segura, J. W. and Patterson, D. E.: Ureteroscopy. J. Urol., 139: 510, 1988. 6. Lingeman, J. E.: Mertz maneuver for catheterizing the tortuous ureter. Endourology, 2(2): 16, 1987. 7. Clayman, R. V.: Catheterizing the tortuous ureter. Endourology, 2(4): 14, 1987. 8. Hulbert, J. C., Reddy, P. K., Hunter, D. W., Young, A. T., Castaneda-Zuniga, W. R., Amplatz, K. and Lange, P. H.: Percutaneous management of ureteral calculi facilitated by retrograde flushing with carbon dioxide or diluted radiopaque dye. J. Urol., 134: 29, 1985. 9. Beckmann, C. F. and Roth, R. A.: Use of retrograde occlusion balloon catheters in percutaneous removal of renal calculi. Urology, 25: 277, 1985. 10. Evans, R. J., Wingfield, D. D., Morollo, B. A. and Jenkins, A. D.: Ureteral stone manipulation before extracorporeal shock wave lithotripsy. J. Urol., 139: 33, 1988. 11. Dretler, S. P.: Stone fragility-a new therapeutic distinction. J. Urol., 139: 1124, 1988. 12. Dretler, S. P., Watson, G., Parrish, J. A. and Murray, S.: Pulsed dye laser fragmentation of ureteral calculi: initial clinical experience. J. Urol., 137: 386, 1987.
