Definitive treatment options for ureteral obstruction

Contributors of Campbell-Walsh-Wein, 12th edition

Stephen Y. Nakada, and Sara L. Best

Clinical presentation

Upper urinary tract obstruction has a variable presentation depending on the etiology and acuity of the obstruction. Workup most commonly involves cross-sectional imaging and, in many cases, a temporizing procedure with either ureteral stent or nephrostomy tube drainage with concurrent retrograde or antegrade studies to further delineate the degree and nature of the obstruction prior to planning definitive management (see Chapter 24 ). One of the most common causes of obstruction is urinary stone disease (see Chapter 27 ). However, numerous non stone related causes of obstruction exist as well and can occur anywhere from the kidney to the bladder.

Indications for repair

While temporizing measures such as stents and nephrostomy tubes with scheduled changes can offer a definitive solution in select situations such as end-of-life care and poor surgical candidates, in general, the goal in managing upper urinary tract obstruction should be a definitive repair that reestablishes normal drainage from the kidney to the bladder and avoids the needs for stents or nephrostomy tubes. Indications for repair include the presence of symptoms, impairment in renal function, development of stones and/or urinary tract infection (UTI) and in rare cases hypertension. The goal of repair should be symptom relief and preservation of renal function. In asymptomatic patients without apparent functional impairment to the kidney, observation with serial imaging and renal scans can be considered. Occasionally, nephrectomy is a more suitable treatment option rather than definitive repair. This can be considered in the event of diminished or absent renal function and a normal contralateral kidney, especially in the setting of chronic infection and/or pain. In general, differential renal function below 15%–20% is the threshold at which the kidney is considered nonsalvageable.

Ureteropelvic junction obstruction (UPJO)

Most cases of UPJO are congenital in nature but may not be identified until later in life. Other etiologies include stone-related or postoperative strictures, neoplastic obstruction, fibroepithelial polyps, or extrinsic compression. Cases of congenital UPJO typically result from intrinsic disease characterized by an aperistaltic segment of the ureter. Histologically, this segment of ureter often has abnormal longitudinal muscle or fibrous tissue distinct from the expected spiral musculature that is usually present. The resulting defect often leads to a ureter that looks grossly normal but does not function appropriately. Other less common etiologies include true ureteral strictures characterized by abnormal collagen deposition or kinks/valves in the ureter that preclude normal antegrade propulsion of urine. Aberrant crossing vessels are also associated with UPJO, having been identified in 63% of patients with UPJO but only 20% among individuals with normal kidneys.

Diagnosis

The routine use of maternal prenatal ultrasonography has led to a dramatic increase in the identification of prenatal hydronephrosis and ultimately UPJO. The diagnosis and management of UPJO in pediatric patients can be found in Chapter 7 . The presentation of UPJO in adolescents, teenagers, and adults is more likely to include intermittent abdominal or flank pain with nausea and vomiting, hematuria, UTI or in rare cases hypertension. Typically, provocative testing with diuretic renography accompanied by Lasix administration confirms the diagnosis. Cross-sectional imaging with computed tomography (CT) and/or magnetic resonance imaging (MRI) can also be utilized to gain anatomic information and identify the presence of a crossing vessel. Ultimately, retrograde pyelography can be used to confirm the diagnosis, though this is commonly accomplished at the time of definitive repair ( Fig. 25.1 ).

Pyeloplasty

When treatment is indicated, the procedure of choice is a pyeloplasty (open, laparoscopic, robotic), though endourologic incisional procedures can be considered as well, particularly in the case of secondary UPJO. Pyeloplasty is most commonly performed in a dismembered fashion whereby the abnormal portion of ureter is fully incised, and the healthy end of the ureter is reanastamosed to the renal pelvis. This is the only approach that allows for complete excision of the diseased area of ureter. It also allows for transposition of the UPJ anterior to or posterior to potential crossing vessels. This can be achieved either by open or minimally invasive laparoscopic or robotic approaches with relatively equivocal outcomes.

Technique.

In the classic Anderson-Hynes technique, the proximal ureter is dissected to the level of the renal pelvis. The abnormal UPJ tissue is excised, and the proximal ureter is spatulated and anastamosed to the renal pelvis in a watertight fashion, typically over a ureteral stent ( Fig. 25.2 ). Reduction pyeloplasty can be performed in cases of extremely capacious renal collecting systems but is typically unnecessary. Contraindications for dismembered pyeloplasty include small intrarenal pelvis and long segment of diseased ureter typically 2 cm or greater. Open pyeloplasty is typically performed via an extraperitoneal flank approach. Laparoscopic pyeloplasty can be performed via a transperitoneal or retroperitoneal approach. One advantage of a transperitoneal approach for laparoscopic repair is larger working space and familiar anatomy. Most commonly, patients stay in hospital overnight with Foley catheter, and surgical drain left in place from 24–36 hours. If drain output increased after the Foley catheter is removed, this is suggestive of ureteral leak from reflux, and the catheter should be replaced for 7 days. The ureteral stent is typically removed 4–6 weeks after surgery. Success rates have been estimated at 95% for open or lap/robotic approaches with the majority of failures occurring in the first 2 years. If failure is identified, repeat pyeloplasty (86% success rate) or endopyelotomy (70% success rate) can be considered.

Special situations

In the case of a small intrarenal pelvis, a ureterocalicostomy can be performed by transecting the lower pole of the kidney and anastomosing the ureter to the lower pole calyx ( Fig. 25.3 ). If stones are present in the kidney, they can be removed at the time of repair via pyelolithotomy. If performed laparoscopically or robotically, endoscopic stone retrieval can be achieved either with laparoscopic instruments or occasionally with passage of a flexible endoscope through one of the working ports. Alternatives to dismembered pyeloplasty typically include creation of flaps out of redundant renal pelvis. Such approaches can be utilized to address a high insertion of the ureter (Foley Y-V plasty) ( Fig. 25.4 ) or long segments of diseased ureter (Culp-DeWeed spiral flap) ( Fig. 25.5 ).