Patient Selection and Preoperative Planning
Proper preoperative patient selection and planning plays a paramount role in optimizing outcomes after antegrade endoscopic management of ureteropelvic junction obstruction (UPJO). Indications for surgical treatment of UPJO include symptomatic obstruction (ipsilateral flank pain, nausea and vomiting, costovertebral angle tenderness), associated urolithiasis, recurrent urinary tract infections (UTIs), or deteriorating renal function. The highly successful outcomes of minimally invasive pyeloplasty have rendered endoscopic management of UPJO suitable only for patients with secondary strictures post pyeloplasty; associated urolithiasis; or major medical comorbidities prohibiting a laparoscopic or robotic approach.
Generally, active UTIs and uncorrected coagulopathy are the only absolute contraindication to antegrade endoscopic treatment of UPJO. Nevertheless, a number of factors have proven to negatively affect the success rate of endoscopic management and considered as relative contraindications such as lengthy strictured segments (>2 cm); severe ipsilateral hydronephrosis; a poorly functioning ipsilateral kidney (<25%), the presence of an aberrant crossing vessel, ischemic strictures, or extrinsic compression of the ureter.
Routine preoperative laboratory investigations should include urine analysis and culture, serum urea and electrolytes with creatinine levels, and a coagulation profile. Imaging studies are helpful in diagnosing the obstructive segment and detecting any associated unfavorable factors. Spiral contrast-enhanced computed tomography is particularly useful to demonstrate any aberrant crossing vessels, and baseline renal ultrasonography provides the basis for comparison with postoperative follow-up imaging. Diuretic renography helps estimate the split function of the obstructed kidney in addition to detecting any significant obstruction. Retrograde pyelography is usually performed concurrently at the time of the intended procedure to localize the diseased segment before any intervention.
A prophylactic intravenous dose of antibiotic is given. After induction of general anesthesia and successful endotracheal intubation on a stretcher, the patient is placed into a prone position. The patient’s arms are slightly flexed at the shoulders, and the elbows are supported. All pressure points are adequately padded, and the chest is supported with a pillow to allow adequate ventilation. The ipsilateral flank and genitalia are widely prepped and draped under strict sterile technique.
Obtaining Percutaneous Access
Initially, flexible cystoscopy is performed in the prone position to identify the ipsilateral ureteral orifice. Intubation of the proper ureteral orifice with 0.038-inch Bentson guidewire is performed under fluoroscopic guidance. The guidewire is advanced as far cephalad as possible. A 5-Fr open-ended ureteral catheter is then advanced over the Bentson guidewire, and the wire is removed. A 16-Fr Foley catheter is inserted into the bladder, and the 5-Fr ureteral catheter is secured to it using waterproof tape. A 60-mL Luer lock syringe filled with dilute contrast is attached to the ureteral catheter. Alternatively, patients may initially be placed in the lithotomy position for ureteral catheter insertion and subsequently be placed prone for the endopyelotomy procedure.
Retrograde pyelography is performed to delineate the pelvicaliceal anatomy and localize the diseased segment. The preferred access is through a posterior mid- or upper pole calyx to provide a straight route to the ureteropelvic junction (UPJ) and ureter using rigid instruments. The C-arm is rotated 30 degrees laterally, (i.e., toward the operator) for a middle posterior calyx. An extra 5 degrees of cephalad rotation of the C-arm is required if a posterior upper pole calyx is chosen for puncture. Air nephrostography might help identify the posterior calyces in difficult cases by gently injecting less than 5 mL of air in a retrograde fashion. Air bubbles reside in the posterior calyces, differentiating them from contrast-filled anterior calyces. Under fluoroscopic guidance, an 18-gauge Chiba needle is advanced toward the tip of the chosen calyx during full expiration. When a pop is felt, the C-arm is rotated 10 degrees medially (i.e., away from the operator) to ensure a straight trajectory of the needle in relation to the punctured calyx with adequate depth. When the needle stylet is removed, urine may be seen confirming adequate position. Alternatively, a gentle trial to pass 0.035-inch hydrophilic tip guidewire into the calyx can be attempted under fluoroscopic guidance. If the tip of the needle is not in the collecting system, the needle should be repositioned or removed and the entire process repeated. Care should be taken not to move the needle when it is within the renal parenchyma to prevent inadvertent parenchymal laceration and increased risk of bleeding.
After proper access is confirmed, antegrade passage of 0.035-inch hydrophilic tip guidewire is performed under fluoroscopic guidance into the collecting system. A small skin incision is made around the wire. Subsequently, a 5-Fr, 40-cm angled-tip Kumpe catheter is advanced over the wire into the collecting system and manipulated to advance the guidewire, passing it down the ureter into the bladder under fluoroscopic guidance. After the Kumpe catheter is advanced coaxially over the wire as far caudad as possible, the wire is exchanged for a 0.038-inch extra-stiff wire, and the Kumpe catheter is removed. The skin incision is then extended to 1 cm, and a 30-Fr balloon dilator is used to dilate the tract before a 30-Fr Amplatz working sheath is inserted under fluoroscopic guidance. Care should be taken to advance the radiopaque tip of the balloon far enough into the calyx but not beyond the infundibulum or the UPJ. In the case of a very tight UPJ or a large redundant renal pelvis, it may not be possible to pass a guidewire into the ureter; in such circumstances, an extra-stiff wire is coiled within the intrarenal collecting system until the collecting system tract is dilated and accessed with the nephroscope. A wire may then be advanced antegrade down the ureter under direct vision to provide secure access.
After the percutaneous access is secured, inspection of the collecting system is performed using a rigid nephroscope. Any renal stones should be dealt with at this stage before incision of the UPJ to avoid dislodgement of stones into the periureteral and perinephric tissues. Careful inspection of the UPJ is performed looking particularly for pulsations that should be avoided during the incision ( Fig. 20.1 ). If not present, a guidewire should be advanced down the ureter before attempting endopyelotomy. At our institution, the preferred endopyelotomy is a cold hook knife, but different options can be used for the incision, including the holmium:YAG (yttrium-aluminum-garnet) laser, endoscopic scissors, or a wire-guided knife according to the surgeon’s preference.