Technique: Percutaneous Antegrade Endopyelotomy

Patients undergoing endopyelotomy should have preoperative imaging performed in order to delineate the length of the narrowed segment, degree of hydronephrosis, presence of a crossing vessel, insertion of the ureter, and presence and location of concomitant stones, ideally with a computed tomography (CT) urogram. Additional considerations when performing a percutaneous antegrade approach include the location of ipsilateral adjacent structures such as the pleura, colon, and spleen or liver. Diuretic renography is helpful to quantify both the degree of obstruction and the differential renal function. Preoperative prophylactic antibiotics are recommended for all patients undergoing both percutaneous renal surgery and retrograde ureteral surgery [29].

Following the induction of general anesthesia, the patient is placed in a prone position. Care is taken to ensure that all pressure points are adequately padded and joints are appropriately supported. Flexible cystoscopy is undertaken in the prone position, and a Teflon-coated guidewire is advanced into the kidney and then replaced with a 5 French (Fr) ureteric catheter. If there is difficulty in navigating the wire beyond the ureteropelvic junction (UPJ), the use of a hydrophilic guidewire (straight or angled) can be helpful. Combining the hydrophilic wire with an angled 5 Fr angiographic catheter (Kumpe catheter) can be utilized to provide additional control in directing the guidewire if there is significant tortuosity of the ureter.

A retrograde pyelogram is then performed to further characterize the narrowing of the UPJ and assist with percutaneous renal access. An upper or middle pole posterior calyx is preferable for renal access as it allows for a straighter path to the UPJ and minimizes torqueing on the renal parenchyma, which can increase bleeding. An 18-guage access needle is used to puncture the collecting system through a renal papilla, and a hydrophilic guidewire is then advanced into the renal pelvis and through the UPJ. The use of a Kumpe catheter can be especially valuable in navigating the guidewire down the ureter. However, due to the narrow UPJ and dilated renal pelvis, it is often not possible to initially advance the wire beyond the UPJ. In this instance, the hydrophilic wire can be exchanged for an extra-stiff guidewire, which is then amply curled within the voluminous renal pelvis, and allows for dilation of the tract.

Tract dilation can be performed with either serial dilators or a balloon catheter, as with standard percutaneous nephrolithotomy. If concomitant calculi are present that require fragmentation and removal, a 30 Fr working sheath should be utilized in order to allow the passage of a rigid nephroscope. If this is not required, a 24 Fr tract is recommended as it allows for the use of a 21 Fr cold knife endopyelotome and reduces trauma to the renal parenchyma. If renal calculi are present, they should be completely removed prior to endopyelotomy in order to avoid the extrusion of stone fragments into the retroperitoneal space.

If a guidewire was not previously placed across the UPJ, once the percutaneous tract has been dilated, nephroscopy can then be used to facilitate the passage of the guidewire down the ureter under direct vision. If this is unsuccessful, a long exchange wire (270 cm) can be advanced through the 5 Fr ureteral catheter in a retrograde fashion and grasped with the rigid nephroscope using the duckbill forceps. The exchange wire is then brought out through the flank, thereby creating through-and-through access. Every effort should be made to pass the guidewire through the UPJ and into the bladder, as through-and-through access is critical to performing a safe endopyelotomy. If a safety guidewire cannot be placed across the UPJ, the procedure should be aborted and an alternative approach selected.

Once a guidewire across the stricture has been secured, the area of a narrowing is dilated with a ureteral balloon-dilating catheter (6 mm-diameter, 10 cm-length) under fluoroscopy. This allows for a clear demarcation of the area of narrowing and increases the working space for the endopyelotome. Endopyelotomy was originally described by Smith et al. utilizing an endopyelotome with a “cold knife” technique [30] (Fig. 14.1). Various blades are available; however, our preference is the hooked blade (Fig. 14.2). Other modalities of incision have been reported, including electrosurgical incision and laser-energy sources; however, outcomes are similar regardless of the cutting modality utilized [8].

Regardless of the tool and energy source used for endopyelotomy, the incision should be made in the true lateral orientation in order to minimize the risk of lacerating a crossing vessel. In addition, prior to the incision, preoperative imaging should be reviewed to identify the location of any potential vessels, and the UPJ area should be closely visualized for any pulsations suggestive of an overlying artery. The incision should encompass the entire length of the narrowed segment and extend at least 1 cm both proximally and distally. Adequate depth is achieved when perinephric fat is visualized. Following the endopyelotomy incision, balloon dilation should be repeated to confirm that all fibrotic bands have been transected.

Following the endopyelotomy, a ureteric stent is inserted in an antegrade fashion; this is based on the technique of intubated ureterotomy described by Davis [31]. There is currently no consensus regarding the optimal stent size and period of stent placement. Some advocate the use of smaller 6–8 Fr stent, while others utilize a larger diameter stent [32]. Our practice is to insert a 14/7 Fr endopyelotomy stent in an antegrade fashion. When Davis initially described the technique of intubated ureterotomy in 1943, a period of stenting for 6 weeks was recommended [31]. However, multiple contemporary series have demonstrated no difference in short-term outcomes with shorter periods of stenting ranging from 2 to 4 weeks [33, 34].

In addition to the ureteric stent, drainage with a nephrostomy tube and Foley catheter is also recommended. We typically utilize a 16 Fr Councill-tip catheter for a nephrostomy tube, which is removed within 48–72 h if the urine is clear and the patient is afebrile. The Foley catheter can be removed once the nephrostomy tube has been discontinued and the flank site is dry. Premature removal of the Foley catheter can cause urine reflux, which may result in persistent flank drainage or urine extravasation.

Once the ureteric stent has been removed, the patient should be followed clinically with regular anatomic imaging, such as a CT urogram or an intravenous pyelogram (IVP), as well as a diuretic renogram. We typically perform an IVP or CT urogram 6 weeks following stent removal, followed by a Lasix renogram 6 weeks later. Repeat imaging should then be performed annually, or sooner if the patient develops recurrent symptoms. There is no consensus on the optimal duration of a follow-up after endopyelotomy. The majority of failures from endopyelotomy occur within the first 2 years; however, recurrences have been demonstrated as late as 10 years after surgery [6, 7]. It is our practice to follow patients with routine imaging for a duration of 5 years.

Technique: Retrograde Endopyelotomy

Retrograde endopyelotomy allows treatment of UPJO without the need for percutaneous access. This provides many advantages such as reduced blood loss, shorter hospital stay, and faster recovery time compared with antegrade endopyelotomy [35]. However, there are some important disadvantages to consider; specifically, a smaller endoscope is utilized, which results in a narrower field of vision, smaller working space, and reduced irrigation flow compared to the antegrade approach. In addition, the presence of renal calculi is a contraindication for retrograde endopyelotomy as there is a risk of extravasation of stone fragments into the retroperitoneal space. In this case of concomitant renal calculi, an antegrade approach is required.

Preoperative preparation is similar to antegrade endopyelotomy with regard to the requirement for preoperative imaging and prophylactic antibiotics. Retrograde endopyelotomy is performed with the patient under general anesthesia and placed in the dorsal lithotomy position. A retrograde pyelogram is performed in order to delineate the anatomy of the UPJ, specifically the length and degree of narrowing. An extra-stiff guidewire is then advanced and coiled in the renal pelvis. If the UPJ is very tight or there is significant ureteral tortuosity, additional techniques utilizing a hydrophilic guidewire with or without a Kumpe catheter can be employed as described above. The placement of a safety guidewire across the UPJ is essential for a safe endopyelotomy, and if a guidewire cannot be placed the procedure should be aborted and an alternative treatment approach should be considered.

Once a guidewire is secured across the UPJ, balloon dilation is then performed across the area of narrowing, utilizing a ureteral balloon-dilating catheter (6 mm diameter, 10 cm length) under fluoroscopy. The balloon should be dilated until a “waist” is no longer present. This will help to delineate the area of narrowing and provide increased working space for the endopyelotomy.

Retrograde endopyelotomy is most commonly performed utilizing a flexible ureteroscope. The length of the male urethra requires the use of a flexible ureteroscope in order to be able to access the UPJ properly. In females, the UPJ can often be reached with a semi-rigid ureteroscope; however, the potential for ureteral trauma with this approach is higher. Consequently, we recommend the use of a flexible ureteroscope in both circumstances. To advance the flexible ureteroscope, a second wire is inserted to the level of the UPJ utilizing either a dual lumen catheter or an 8/10 Fr coaxial dilator. The ureteroscope is then passed over the second wire, in a coaxial fashion under fluoroscopy, up to the level of the UPJ.

Prior to making the endopyelotomy incision, the UPJ area should be closely visualized for any pulsations, which may indicate an overlying crossing vessel. Similar to the antegrade approach, the incision should be made in the true lateral direction and extend 1 cm both proximal and distal to the area of narrowing. The incision should reach a depth where periureteral fat is visualized. Multiple mechanisms for making the incision have been described, including the Bugbee electrode and the Holmium:YAG laser; however, the laser is most commonly utilized [6]. A 270 nm laser fiber is small enough to permit adequate irrigation flow and a deflection of the flexible scope, which allows for adequate precision of the endopyelotomy incision. Typical laser settings are 0.5–1.5 J/pulse with a rate of 5–15 Hz. Following laser incision, balloon dilation of the UPJ should be repeated to ensure a complete incision of the narrowed segment.

Following the completion of the endopyelotomy, a stent is inserted in a retrograde fashion. As discussed above, there is no consensus regarding the ideal size and duration of the stent following endopyelotomy. It is our practice to place a 14/7 Fr endopyelotomy stent at the end of the procedure. We typically utilize a stent one size longer than the patient’s height in order to prevent downward migration of the proximal coil of the stent into the freshly incised UPJ [10]. A Foley catheter is placed for 48 h, and the stent is removed after 6 weeks. Once again, follow-up anatomical and functional imaging is required, and is performed as described above.

Ureteral Strictures

The etiology of ureteral strictures include trauma, stone impaction, radiation, malignancy, and infection, with the most common cause being iatrogenic injury from gynecological, vascular, general surgical, or endoscopic procedures [36]. The overall rate of ureteral stricture formation following ureteroscopy is estimated to be 1% but has shown to increase to 5–24% with a long duration of stone impaction [36].

A plethora of reconstructive and endoscopic procedures can be considered for the management of ureteral strictures. Technique selection depends on a number of important factors, including the length, location, and etiology of the stricture, as well as the degree of periureteral tissue involvement, ipsilateral and global renal function, and the patient’s overall health status. A variety of surgical reconstructive procedures, including ureteroureterostomy, ureteroneocystostomy, Boari flap, transureteroureterostomy, ileal ureteral interposition, and renal auto-transplant, can be performed through open, laparoscopic, or robotic approaches. While these techniques typically offer more definitive management with higher reported success rates, they are associated with increased operative morbidity and longer recovery times.

Alternatively, a number of endoscopic management options have evolved, including ureteral stent placement, balloon dilation, and endoureterotomy. While success rates for these procedures are inferior to surgical reconstruction, they remain an important option for the treatment of ureteric strictures in the appropriately selected patient. An understanding of the etiology of the stricture, as well as its anatomical characteristics, can aid in selecting the most appropriate treatment choice. Preoperative imaging should include a contrast study such as an IVP, CT urogram, and retrograde or antegrade pyelogram in order to characterize the stricture location, length, and caliber of the lumen. Strictures with a completely obliterated ureteral lumen will fail endoscopic approaches and should be treated with a surgical reconstruction. Diuretic renography should also be performed in order to determine both ipsilateral and global renal function, as well as the degree of obstruction. If ipsilateral renal function is considerably compromised, nephrectomy may be the most appropriate treatment modality.

Endoscopic management of ureteric strictures is best suited for patients with benign or nonischemic etiologies, short stricture length (<2 cm), good ipsilateral renal function (>20%), and nonradiated fields and patients who have not previously failed the management of their stricture [37]. In addition, endoscopic techniques offer the advantage of shorter operative time, decreased morbidity, reduced hospital stay and recovery times, lower cost, and improved cosmetic results [17].

Ureteral stent placement is an effective short-term intervention that relieves the effects of obstruction and protects the kidney from damage while definitive therapy is being considered. In very select patients who are not candidates for reconstructive procedures, such as those with significant medical comorbidities or a short life expectancy, a chronic indwelling stent may be a reasonable management option. In this circumstance, the ureteral stent must be exchanged every 3–4 months in order to prevent encrustation.

Balloon dilation alone is rarely an effective treatment for ureteral strictures with only modest reported success rates of between 40% and 75% [38]. However, in selected circumstances when there is a short segment stricture with minimal periureteral fibrosis and no ischemia, ureteral strictures can be managed with balloon dilation alone [39]. Balloon dilation has also been shown to be less effective for strictures located in the mid-ureter [39]. Previous studies have failed to demonstrate an optimal balloon diameter and pressure, with most studies reporting similar outcomes [40]. Given that balloon dilation alone is rarely effective as a monotherapy, it is more commonly used in conjunction with endoureterotomy.

Similar to endopyelotomy, endoureterotomy can be performed using either an antegrade or retrograde approach. Strictures involving the distal and mid-ureter are typically approached in a retrograde fashion with a semi-rigid ureteroscope, while proximal ureteric strictures can be treated through a percutaneous antegrade approach or retrograde technique utilizing a flexible ureteroscope. Reported success rates are comparable for each approach and range from 66% to 83%; the reported outcomes of several contemporary series with long-term follow-up are listed in Table 14.3 [41–53]. The average complication rate following endoureterotomy is reported to be 5.7%, and specific complications are outlined in Table 14.2 [12]. The following section details the surgical steps involved in endoureterotomy.

Table 14.3

Selected contemporary results of endoureterotomy

Author	Number of patients	Success rate (%)			Mean follow-up in months (range)
		Orthotopic	Transplant	Ureteroenteric
Razdan et al. [41]	50	74			75 (6–108)
Lane et al. [42]	19	68			36 (5–84)
Hibi et al. [43]	18	80			60 (46–74)
Gnessin et al. [44]	35	79			27 (10–72)
Kristo et al. [45]	3		100		24 (6–33)
Gdor et al. [46]	6		67		58 (13–89)
He et al. [47]	8		62		16 (4–45)
Mano et al. [48]	12		83		44 (2–68)
Laven et al. [49]	16			57	20 (9–41)
Watterson et al. [50]	23			71	23 (3–68)
Poulakis et al. [51]	40			60.5	38 (12–85)
Milhoua et al. [52]	15			33	23 (6–86)
Hu et al. [53]	32			69	22 (6–36)

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