Ureteroscopy Treatment & Management

Ureteroscopy can be divided into diagnostic endoscopy and therapeutic treatments.

Diagnostic Ureteroscopy

Atraumatic diagnostic endoscopy minimizes mucosal distortion, allowing for complete mapping of the upper urinary tract. Ureteroscopic access is obtained with a wireless technique, if possible. The ureteral orifice is visualized and intubated without the assistance of a guidewire. The intramural ureter is traversed employing a "no-touch" technique, and the more proximal ureter and renal collecting system are then mapped. In a recent prospective study of 460 consecutive upper-tract endoscopies, no-touch ureteroscopy was successfully performed in most patients without prior stenting or ureteral dilation. ^[9] This wireless form of flexible ureteroscopy eliminates the potential trauma, mucosal irritation, and inadvertent manipulation of stones or tumors caused by guidewires and is particularly helpful when the collecting system is evaluated for mucosal/intra-luminal lesions.

Fluid irrigation facilitates passage of the ureteroscope while simultaneously clearing the optical field. Sterile saline is the preferred irrigant. Although automatic pumps are available for this purpose, hand irrigation is preferred for its precise control of volume dispensed.

When wireless flexible ureteroscopy is not feasible, a small-diameter rigid ureteroscope can be employed first to inspect and map the ureter. A guidewire is then placed only to the area that already has been inspected, and then a flexible instrument is the passed over it in a monorail fashion, under fluoroscopic guidance, to complete the mapping. The flexible ureteroscope is directed from calyx to calyx, and frequently dilute contrast material is injected through the working channel of the endoscope to help ensure the entire collecting system is inspected as depicted below.

Therapeutic Ureteroscopy

Therapeutic ureteroscopy is used in varied applications, including in the treatment of stones, urothelial tumors, and stricture disease.

Management of Stone Disease

Ureteroscopy is a safe and minimally invasive method of treating stone disease in the kidneys and ureter as shown below. It can be used either as primary therapy or as salvage therapy for residual stones following treatment with other modalities such as extracorporeal shockwave lithotripsy (ESWL) and/or percutaneous nephrolithotomy (PCNL). Compared with ESWL, ureteroscopic lithotripsy achieves a greater stone-free state. ^[10] Success rates following ureteroscopy are shown in Table 2 and Table 3 in the Outcome and Prognosis section below.

Furthermore, in select cases, ureteroscopy has been shown to be a viable and effective means of treating stone disease where ESWL may be contraindicated, such as in pregnant women and pediatric patients. In fact, a study by Freton et al indicated that in pediatric patients with stones of the upper ureter or kidney, the achievement of stone-free status in a single session was more likely with flexible ureteroscopy than with ESWL. The investigators found that after a single procedure, 37% of patients who had undergone flexible ureteroscopy were stone free, compared to 21% of patients who were treated with ESWL, even though there was more complexity to the urinary stones (a higher rate of multiple stones and lower-pole calculi) in the ureteroscopy group. ^[11]  Prattley and colleagues have demonstrated the efficacy of this modality in the elderly population, with significant initial and final stone-free states (88%; 97%), with 73% of cases performed as day surgery procedures. ^[12]

Urothelial Malignancy

Ureteroscopy is also a powerful tool in the diagnosis, treatment, and surveillance of transitional cell tumors of the upper tracts. ^{[13, 14]}

See image below.

Stricture Disease/Obstruction

In addition, ureteroscopy can be employed to treat ureteral stenosis/stricture and ureteropelvic junction obstruction. In each setting, an energy source is delivered through the working channel of the endoscope to fragment, ablate, and/or incise. Additional accessories can also be passed through the standard 3.6F working channel to remove stone fragments or to obtain biopsy samples (see Intraoperative details).

Prior to ureteroscopic examination, the surgeon must have the appropriate instrumentation available. This includes endoscopes, accessories, appropriate energy sources, and fluoroscopy.

Rigid ureteroscope specifications include the following:

• Tip diameter - 4.5-9.5F (6.9F most common)

• Optics - Fiberoptic bundles or digital imager

• Working channels - One, 2, or 3 (2 channels preferred)

• Accessory length - 40 - 60 cm

Flexible ureteroscope specifications include the following:

• Tip diameter - 6.9-9.8F (7.5F most common)

• Optics - Fiberoptic bundles or digital imager

• Working channel - Single, 3.6F

• Access - Guidewire (0.035 in nitinol or 0.038 in stainless steel)

• Accessory length - 100 - 120 cm

Energy sources include the following:

• Holmium:yttrium-aluminum-garnet (Ho:YAG) laser

• Neodymium:yttrium-aluminum-garnet (Nd:YAG) laser

• Thulium: YAG laser

• Thulium laser fiber laser

• 1470 nm diode laser 

• Electrocautery

• Electrohydraulic lithotripsy

• Mechanical impactor (ie, Lithoclast)

Prophylaxis is as follows:

• All patients receive a preoperative dose of a broad-spectrum parenteral antibiotic

• Patients with positive cultures should receive appropriate treatment course, based on sensitivity panel

When therapeutic ureteroscopy is performed, a guidewire can be useful. It can help facilitate multiple passes of the instrument while maintaining access to the upper urinary tract. For example, during treatment of a distal ureteral stone, a rigid ureteroscope is passed up the ureter beside the guidewire and laser energy is delivered through a small quartz fiber to fragment the stone. An accessory such as a wire prong grasper or basket then can be used to extract fragments with multiple passes of the endoscope (see video below). 

Ureteral access sheaths have utility but generally only in select settings. A meta-analysis that studied the routine use of access sheaths found no difference in stone-free rate, operative time, length of stay, or intraoperative complications. ^[8]  However, postoperative complications were appreciably higher. Additionally, other studies have found evidence of elevations in expression of COX-2 and TNF-α, tissue ischemia, and tissue necrosis, particularly in the distal ureter, ^{[8, 15]}  which correlates with earlier studies documenting injury by ureteral access sheaths. ^[5]  A ureteral sheath can be employed, but its relatively large diameter (≥11F) may potentiate ureteral wall trauma as described earlier. ^[5]

There are a variety of stone extraction devices available. Those composed of nitinol, which maintains its shape and rarely kinks, are preferred, as depicted in the video above.

If electrocautery is to be employed, special attention to the guidewire choice helps minimize energy scatter. If a standard stainless steel guidewire is used, electrical current may inadvertently arc to the wire and result in thermal injury. This can be prevented by using an insulated guidewire such as a Teflon-sheathed nitinol guidewire (eg, Zebra wire, Boston Scientific, Natick, Mass).

Intraluminal ultrasonography has been used in various applications. It offers enhanced diagnostic yield in the evaluation of disease processes such as ureteropelvic junction obstruction, tumors of the upper tract, and anatomic anomalies (eg, crossing renal vessels). It has also improved treatment of hidden or submucosal ureteral calculi.

Special Consideration: The Impacted Distal Calculus/The Tight Intramural Ureter

A particular therapeutic quandary can be the impacted distal ureteral stone. When a guidewire cannot be passed cystoscopically, employing a small diameter semi-rigid ureteroscope is useful in gaining access to the proximal ureter. The tip of the endoscope is placed into the edema and a guidewire is passed proximally beyond the obstruction under direct vision.

In the case of a tight intramural ureteral tunnel, after a guide wire is passed into the proximal collecting system, a two wire access technique is often helpful. In this setting a small caliber, two-channel semi-rigid ureteroscope is passed just to the ureteral orifice beside the pre-placed safety guide wire. A second guide wire is passed through the working channel proximally under direct endoscopic and fluoroscopic guidance. Irrigation is administered thru the second endoscopic working channel to clear the optical field and the endoscope rotated placing its tip between the two guide wires. The semi-rigid ureteroscope is then gently passed proximally between the two wires, compressing the edema and gently dilating the distal segment until the calculus is encountered. Once at the level of the calculus, the second wire is removed and lithotripsy can commence.

In circumstances where ureteral endoscope access proves difficult, staged interventions with first stenting to drain the system have proven to be particularly effective, approaching 100% access rate after stenting. This pre-stenting facilitates passive ureteral dilation over time. While optimal duration of stenting varies, some studies demonstrated good results in as little as 3-5 days. ^{[16, 17]}

Special Consideration: Anomalous Kidneys 

In selected populations with aberrant upper urinary tract anatomy, ureteroscopy is frequently successful, with reduced risk of complications compared to PCNL, and increased overall success/stone clearance as compared to ESWL. ^[18]

When the ureteroscopy is completed, internal ureteral stents are commonly placed to facilitate healing and to ensure drainage, particularly if vigorous therapeutic maneuvers were performed and/or the ureter required dilation for access. However, simple diagnostic ureteroscopy without ureteral dilation does not routinely require postoperative ureteral stenting.

Internal ureteral stents are associated with lower urinary tract symptomatology, including urinary frequency, urgency, and mild-to-moderate hematuria, which is transient. Ureteral stents are removed after a period of healing that can range from a few days to 6-8 weeks, depending on the complexity of the treatment. Stents are usually removed in the office with either an attached nylon trailor or cystoscopically.

Most ureteroscopic procedures are performed as day surgery outpatient procedures. On discharge prophylactic oral (quinolone-based) antibiotics and analgesics are frequently prescribed. Anticholinergic medications and alpha-blockers can be used to minimize frequency, urgency, and discomfort often associated with ureteral stents; however, individual patient tolerance varies widely. Careful selection of the best stent length and optimal positioning help to minimize these unpleasant symptoms.

Most patients are return after 1-2 weeks following the ureteroscopic procedure for stent removal and surgical follow-up. If endoscopic lithotripsy was performed, serial imaging (eg, plain radiography or ultrasonography) is performed to define residual stone burden.

Subsequent imaging is required and tailored to the clinical presentation and underlying disease process. If, for example, a ureteral stricture is incised ureteroscopically, serial follow-up imaging studies defining drainage and renal function (eg, IVP or CT urography and nuclear medicine renal scan) are performed periodically, particularly during the first year to ensure an acceptable surgical outcome.

Minor intraoperative complications

Minor ureteroscopic complications are those that have no long-term deleterious effects and, if treated promptly, cause only minimal or transient postoperative problems. Table 1 (below) chronologically lists 5 studies spanning the almost 20-year evaluation of ureteroscopic equipment and technique. In the initial series from the Mayo Clinic, large-diameter endoscopes were used, ^[19] while, in the last two series, the smallest-diameter ureteropyeloscopes were used, with a noticeable decrease in complication rates. ^{[20, 21]}

In general, the minor complication rate associated with ureteropyeloscopy was decreased based on refined technique, experience of the operators, and prompt treatment or prevention of intraoperative problems. Prophylactic parenteral antibiotics, careful guidewire placement, endoscope minimization preventing excessive ureteral dilation, and postoperative ureteral stenting all have decreased the rate of postoperative problems. This, combined with better surgical training and improved instrumentation, has resulted in this very positive trend.

Major intraoperative complications

Major intraoperative problems associated with ureteroscopy include trauma to tissues leading to significant ureteral wall perforations, avulsions, or foreign body (eg, stone) migration into the ureteral wall. The major complication rate has markedly decreased (now occurring in less than 1% of all ureteroscopic procedures). As with the minor problems, major complications are less common for basically the same reasons. However, when they do occur, treatment is more complex.

Major ureteral wall perforations can be the product of improper application of an endoscope, dilator, or sheath. The forceful positioning of any device, particularly in young patients with a small caliber ureter, can lead to ureteral wall trauma. Pre-operative placement of a double-J stent is often unnecessary, but is recommended when unusual difficulty in access is encountered, or when a strictures is found. Pre-stenting greatly facilitates complex ureteroscopy.

Ureteral wall trauma may lead to stone migration into the wall or outside the urinary tract. Subsequently, this may result in the formation of a stone granuloma and ureteral wall strictures. Meticulous clearance of stone fragments in this setting and stent drainage will minimize the risk of subsequent stricture.

When a minor problem is encountered during ureteroscopy, taking appropriate measures to prevent progression is essential. Additionally, the inappropriate application of endoscopes, lithotrities, and accessories can lead to surgical misadventure. An example would be basketing a relatively large renal stone with a retrograde-placed ureteroscope and attempting extraction rather than fragmentation.

A basic concern is that, if the stone was too large to pass, how does engagement in a basket and application of tension along the long axis of the ureter have merit? Surgeons can find themselves in a tenuous situation in which extraction is impossible; stone disengagement is difficult, and, with a single endoscopic working channel, simultaneous placement of an endoscopic lithotrite is difficult or impossible. Excessive tension on the ureter can lead to an avulsion, with disastrous complications.

Allowances or contingencies should be made for stone fragmentation if extraction is deemed too difficult or dangerous. If treatment is challenging and/or access difficult, placing a stent and returning another day is a better plan, or consider an alternative technique such as percutaneous access or extracorporeal shockwave lithotripsy. Such planning can prevent complications and poor outcomes.

Recent case reports in the literature defined an issue with a specific flexible endoscope, where the outer jacket accordioned intraoperatively, resulting in a distal tip that was too large to extract. Consequently, the endoscope could not be removed. While the manufacturer in question performed a recall of this particular model, practitioners are nonetheless cautioned to perform careful inspection of their equipment prior to insertion to confirm stability of the device. ^[22]

If ureteral avulsion occurs in the distal segment, repair is based on standard open or laparoscopic surgical technique of ureteral reimplantation. Ureteroneocystostomy can be performed for most distal ureteral avulsions, with a psoas bladder hitch used if necessary, to create a tension-free anastomosis. A Boari bladder wall flap can increase the proximal extent of the repair to the middle third of the ureter. These repairs are usually performed over a ureteral catheter with perianastomotic drainage. This can be performed at the time of the injury or in a staged fashion after proximal percutaneous drainage is obtained.

The more proximal ureteral avulsion requires the most complex surgical repair. If a proximal ureteral avulsion is encountered intraoperatively and most of the ureter is intact, primary repair over a ureteral catheter can be performed. Unfortunately, in this setting the ureter is often devitalized. If the entire devitalized ureteral segment is brought into the bladder, it is of no value in subsequent repair. Percutaneous renal drainage should be obtained immediately for this type of ureteral injury. Subsequent therapy is based on either bowel interposition (ie, ileal ureter) or renal autotransplantation to a pelvic position. Both procedures are highly complex and have their own inherent risks.

Table 1. Comparison of Complication Rates Associated With Ureteroscopy, Emphasizing the Noticeable Decrease in the Major Complication Rate With Greater Experience and Endoscope Miniaturization (Open Table in a new window)

 

UTI= urinary tract infection; CVA= cerebrovascular accident; DVT= deep vein thrombosis; MI= myocardial infarction

The outcome of a ureteroscopic procedure is based on the underlying disorder and whether a diagnostic or therapeutic endoscopy was performed. In diagnostic ureteroscopy, finding the source of bleeding, or defining the nature of a filling defect (with tissue sampling for biopsy) is usually the end point.

Therapeutic ureteroscopy for the treatment of upper urinary tract calculi should resolve ureteral obstruction and decrease the stone burden. Endoscopic treatment of stricture disease should improve drainage. Treatment of urothelial tumors has the same goals and end points as endoscopic treatment of bladder tumors. Thus, ureteroscopy is a surgical platform from which various disease processes can be treated, each with their own specific postoperative expectations and outcomes.

The following tables show success rates of ureteroscopic lithotripsy.

Table 2. New York University Experience With Ureteroscopic Treatment of Ureteral Calculi Using the Holmium:YAG Laser (Open Table in a new window)

Table 3. New York University Experience With Ureteropyeloscopic Treatment of Intrarenal Calculi Using the Holmium:YAG Laser (Open Table in a new window)

 

Advances in technology and surgical technique have paved the way for the endoscopic treatment of larger stone burdens. The ureteroscopic treatment of large upper urinary tract calculi was first described in patients with comorbidities prohibiting percutaneous nephrostolithotomy in 1998. ^[25] Over the last 15 years, multiple centers have presented their experience with similar large stones treated ureteroscopically with excellent stone-free rates and minimal morbidity, as exhibited in Table 4. ^[26]

Technological advances, including new laser energy sources (Ho:YAG and thulium laser fiber lasers) facilitate efficient treatment of larger stone burdens. This is underscored in the setting of PCNL salvage, ^[27]  particularly in high-risk populations. It has been found to have equivalent stone-free rates and is preferred to PCNL in high-risk patient populations, with shorter length of stay and increased rates of stone-free clearance. ^[27]  

Table 4. Review of Studies on Ureteroscopic Management of Upper Urinary Tract Calculi > 2 cm (Open Table in a new window)

 

Miniaturization of ureteroscopic instrumentation will continue, with smaller fiberoptics and enhanced digital imagers, improved accessories, and new energy sources. As the instrumentation becomes smaller and more refined, it also will become more delicate. Thus, manufacturers are challenged to develop new, smaller instruments that will also survive the rigors of surgical therapy. 

Single-use endoscopes were introduced to increase ureteroscope availability where automated sterilization is not available. Factors impacting their utility include size, expense, image quality, deflectability, and capacity to adequately navigate the ureter. ^[34]  Other factors under consideration include case volume, surgical skill, and presence and quality of in-house sterile processing. Cost-effectiveness is multifactorial, and, as such, no conclusive statement can be made. ^[34]