Treatment of Ureteral Stones
Treatment options
The current treatment options for ureteral stones include ESWL, ureterorenoscopic lithotripsy, laparoscopic and open surgery, lithotripsy and drug therapy (see Table VII-9). The vast majority of ureteral stones can be treated satisfactorily with ESWL and ureterorenoscopic lithotripsy. Patients who fail minimally invasive treatment often require open surgery to retrieve the stone. Laparoscopic surgery is minimally invasive and can be used as an alternative to open surgery. Both methods can also be used when ESWL and ureteroscopic treatment are contraindicated, such as when the stone is located in the proximal end of a narrow segment of the ureter.
There is an ongoing debate as to which is more minimally invasive, ESWL or ureteroscopic lithotripsy, with opposing views for each method. Although ESWL is more likely to be re-treated than ureteroscopy, it has the advantage of being minimally invasive and requiring no anesthesia, and even with the addition of various adjunctive measures, ESWL is still a minimally invasive treatment.
On the other hand, in most of the literature, ureteroscopy is considered as a “one-step” treatment performed under anesthesia. Several controlled studies between ureteroscopy and ESWL have been reported in the literature, but most of the focus has been on distal ureteral calculi. Although some of these findings have been confirmed in the literature, a few still believe that ESWL should be preferred for the treatment of ureteral stones due to its minimally invasive nature.
In conclusion, it is difficult to determine which of these two approaches is superior. For the urologist, the choice of the most appropriate treatment for a patient depends on his experience, the equipment available and the treatment environment.
It is important to note that only pure uric acid stones can be lithotripsed by oral lithotripsy, while those containing ammonium urate or sodium urate cannot. For stones showing hypodense shadow on X-ray, ESWL can be tried with the assistance of ureteral catheter or double J tube for positioning. uric acid stones can be lithotripsed by local instillation of alkaline drugs under close observation if the catheter successfully reaches the top of the stone during retrograde ureteral intubation for diagnosis and drainage treatment, which is faster than oral lithotripsy.
Extracorporeal shock wave lithotripsy (ESWL)
Most of the ureteral stones can be treated with in situ lithotripsy with satisfactory results and low incidence of complications and side effects. Since ureteral stones are often relatively embedded in the ureteral lumen, they lack a fluid environment around them that is conducive to stone crushing, making them more difficult to crush compared to kidney stones of the same size. Therefore, ESWL treatment of ureteral stones usually requires a higher shock wave energy and a greater number of impacts. For complex stones (stones that are too large or very tightly packed), a combination of ESWL and other minimally invasive treatment modalities (such as ureteral stenting or ureteroscopic lithotripsy) is required.
The efficacy of ESWL is related to the size of the stone, the degree of stone encapsulation by the tissue and the stone composition, and the re-treatment rate is higher for large and dense stones. ESWL is preferred for upper ureteral stones ≤1 cm in diameter, and ESWL, ureteroscopy (URS) and PNL can be chosen for stones >1 cm in diameter; ESWL and URS can be used for middle and lower ureteral stones.
Most ureteral stones can be treated with satisfactory results by in situ lithotripsy, while some ureteral stones can be treated with in situ lithotripsy by placing a ureteral stent tube and passing the stone or leaving it underneath the stone; it is also possible to push the ureteral stone retrogradely into the renal pelvis before lithotripsy.
Ureteroscopic lithotripsy
Since the ureteroscope was used in the clinic in the 1980s, the treatment of ureteral stones has undergone fundamental changes. The application of new small-diameter rigid, semi-rigid and flexible ureteroscopes, the extensive combination of new lithotripsy equipment such as ultrasonic lithotripsy, fluid electrolysis, pneumatic ballistic lithotripsy and laser lithotripsy, and the application of ureteroscopic direct vision lithotripsy basket extraction have greatly improved the success rate of minimally invasive treatment of ureteral stones.
The choice of ureteroscopic stone extraction or lithotripsy method should be based on the site, size, composition (density) of the stone, co-infection, available instruments and equipment, the technical level and clinical experience of the urologist, as well as the patient’s own conditions and wishes.
(1)Indications
1) Ureteral stones in the lower part of the ureter.
2)Middle ureteral stones.
3) Upper ureteral stones after failed ESWL.
4) “Stone street” after ESWL.
5)Stones complicated by suspected uroepithelial tumor.
6)Ureteral stones with negative X-rays.
7) Embedded stones with long residence time and difficult ESWL.
(2) Contraindications: (see section on percutaneous nephrolithotomy).
(3) Preoperative preparation: (see section on percutaneous nephrolithotomy).
(4) Operation method
(1) There are three types of ureteroscopes currently in use: rigid, semi-rigid and flexible. Rigid and semi-rigid ureteroscopes are suitable for lithotripsy and stone extraction of middle and lower ureteral stones, while soft ureteroscopes are mostly suitable for lithotripsy and stone extraction of middle and upper ureteral stones, especially upper segment or renal stones (see percutaneous nephrolithotomy section).
2) The patient is placed in a lithotomy position, the bladder is first examined using the ureteroscope, and then the ureteroscope is introduced under the guidance of a safety wire (guide wire). Whether the ureteral opening needs to be dilated depends on the thickness of the ureteroscope and the size of the ureteral lumen. Both rigid or semi-rigid ureteroscopes can be inserted retrograde into the upper ureter under fluoroscopic surveillance. A flexible ureteroscope requires insertion into the ureter under its guidance with the aid of a 10-13F ureteroscope sheath or a safety guidewire guided through a connector (see the section on percutaneous nephrolithotomy). During the approach, the pressure and flow rate of the irrigating fluid are adjusted using a syringe or a liquid perfusion pump to maintain a clear surgical view.
(3) For stones in the middle or upper ureter or stones at the PUJ or larger stone fragments, the following methods can be used to prevent or reduce stone slippage back into the renal pelvis or calyces: (1) the pressure of the irrigation fluid should be minimized; (2) adjust the position such as head-high foot position; (3) reduce the energy and frequency of lithotripsy; (4) use a lithotripsy basket to fix the stone before lithotripsy; (5) lithotripsy starts from the edge of the stone side and try to (5) Start from the edge of the stone and try to break the stone into pieces, leaving the ureteral side of the stone to be broken at the end.
(4) After the stone is seen by ureteroscopy, the stone is crushed into pieces less than 3 mm by using lithotripsy equipment (laser, pneumatic ballistic, ultrasound, liquid electricity, etc.). For those small stones and fragments ≤5mm in diameter, they can also be removed by lithotripsy basket or stone extraction forceps.
5) Postoperative placement of double J-tube: It is still controversial whether to place double J-tube after ureteroscopic lithotripsy. In the following cases, it is recommended to place double J tubes: (1) large embedded stones (>1cm); (2) obvious edema or bleeding of ureteral mucosa; (3) ureteral injury or perforation; (4) polyps formation; (5) ureteral stenosis with (without) simultaneous ureteral stenosis endotomy; (6) large stones with significant fragment load after lithotripsy, requiring postoperative stone removal; (7) incomplete lithotripsy or lithotripsy failure, requiring postoperative ESWL treatment is needed after the operation; ⑧ with obvious upper urinary tract infection. Generally, double J tube is placed for 1 to 2 weeks, or 4 to 6 weeks if ureteral stricture endotomy is performed at the same time.
(6) Complications and their management: The incidence of complications is significantly related to the equipment used, the technical level of the operator and the condition of the patient itself. The current literature reports a complication rate of 5% to 9%, with more serious complications occurring at a rate of 0, 6% to 1%.
a. Recent complications and their management: ① infection: apply sensitive antibiotics to actively anti-infection treatment; ② submucosal injury: place double J stent tube to drain for 1 to 2 weeks; ③ false tract: place double J stent tube to drain for 4 to 6 weeks; ④ perforation: one of the main acute complications, small perforation can be placed double J stent tube to drain for 2 to 4 weeks, if the perforation is serious, surgical repair (ureteral end-to-end anastomosis, etc.) should be performed. ⑤ Ureteral mucosal avulsion: it is one of the most serious acute complications and should be actively surgically reconstructed (autologous kidney transplantation, ureteral bladder anastomosis or ileal substitution ureteroplasty, etc.).
b. Long-term complications and their management: Ureteral stenosis is one of the major long-term complications, with an incidence of 0.6% to 1%. Ureteral mucosal injury, pseudo-channel formation or perforation, ureteral stone entrapment with polyp formation, and ureteral mucosal destruction due to multiple ESWL are the main risk factors for ureteral stenosis. The long-term complications and their management are as follows: ① ureteral stenosis: ureteral stenosis endotomy or stenosis segment resection end anastomosis; ② ureteral occlusion: stenosis segment resection end anastomosis or ureteral bladder reimplantation; ③ ureteral reflux: mild: follow-up; severe: ureteral bladder reimplantation.
Percutaneous nephrolithotomy .
Open surgery and laparoscopic treatment of ureteral stones Open surgery is only used when ESWL and ureteroscopic lithotripsy and stone extraction treatments have failed. In addition, open surgery can be used in cases where ureteroscopic stone extraction or ESWL is contraindicated. Posterior laparoscopic ureterotomy can be used as an alternative to open surgery.
Lithotripsy.
Bilateral stones are treated with staged surgery. With the update of extracorporeal lithotripsy and endolithotripsy equipment and the advancement of minimally invasive urological techniques, bilateral upper urinary tract stones can be treated with simultaneous minimally invasive surgery for some patients with better general condition and relatively easy stone removal.
The treatment principles for bilateral upper urinary tract stones are: ① Bilateral ureteral stones, if the total renal function is normal or in the compensatory phase of renal insufficiency, and the blood creatinine value.