Search

The ureter is the tube that allows passage of urine from the kidneys to the bladder. It can become blocked by stones. Treatment to remove such stones varies, depending on the location of the stones. If the stones are lodged toward the lower end of the ureter, they can usually be removed directly with a ureteroscope. On the other hand, if they are in the upper third of the ureter, shock wave lithotripsy, fragmentation of the stones with shock waves, is normally used. Such stones are usually pushed with a catheter back into the kidneys prior to lithotripsy, as stones that are bathed in urine or other fluids respond much better to the procedure. The more difficult situation is where the stones can neither be reached with a ureteroscope nor pushed back into the kidneys. This study reported on the treatment of ureter stones with lithotripsy where the stones initially could not be manipulated with either a ureteroscope for direct removal nor with a catheter to push the stones into the kidneys. Lithotripsy was used to treat 261 stones that did not respond to initial manipulations and remained in place in the ureter. Fragmentation was successfully achieved for 254 (97 percent) of the stones, with 219 (86 percent) successfully fragmented with only one lithotripsy treatment. Thirty more cases were successful after two treatments and five cases were successful after three treatments. Retrograde catheters were in place when the lithotripsy was performed on 215 (82 percent) patients. Neither the presence nor the placement of these catheters affected treatment outcomes. In 81 cases, some type of intervention was required following lithotripsy to help remove the stones. These results indicate that lithotripsy can be highly successful in treating ureteral stones that cannot be manipulated by other means. (Consumer Summary produced by Reliance Medical Information, Inc.)

Until recently, treatment for stones in the ureter, the tube connecting the kidney and the bladder, was limited to either close observation to see if the stone passed on its own, manipulating it with a scope to get it to pass, or surgery. New treatments include dissolving the stone with shock waves (extracorporeal shock wave lithotripsy, or ESWL) and using a ureteroscope to manipulate and remove the stone. ESWL is preferred when the stone is in the upper third of the ureter, while the ureteroscope is usually used when the stone is in the lower third of the ureter. ESWL is most effective when the stone is surrounded by fluid (i.e. urine). This can be accomplished by passing a catheter past the blocked area or by pushing the stone into the kidneys. In the January 1990 issue of Radiology, Barr et al. report that ESWL can be highly successful, even when the catheter cannot be passed through the blockage and treatment with a ureteroscope fails. These researchers used a higher number of shock waves than is normally used. The ureteroscope is more successful in treating stones when the stones are more distal (lower). The instrument used is rigid and it is difficult to manipulate it beyond a certain point in the ureter. When it is used, the stone is caught in a basket and then removed or destroyed. Success in using this technique is highly dependent upon the skill of the technician using the scope. The more problematic situation is where the stone cannot be removed with the ureteroscope nor can it be pushed into the kidney. Although the study by Barr reported success with repeated ESWL treatments, it did not mention whether repeated ureteroscopic treatments were attempted. Once the ureteroscope reaches the stone, repeat treatments are rarely required, unlike ESWL. The Barr study certainly indicates that ESWL is useful as a secondary treatment for stones that cannot be reached with a ureteroscope or a catheter, but this situation involves only a small population of the patients with these stones. Ureteroscopic extraction of stones from distal regions, and the middle regions if they can be reached, of the ureter is still preferable to ESWL. (Consumer Summary produced by Reliance Medical Information, Inc.)