30 Michael W. Sourial,1 Bodo E. Knudsen,1 & Paul J. Van Cangh2 1 Department of Urology, The Ohio State University Wexner Medical Center, Columbus, OH, USA 2 University of Louvain Medical School, Department of Urology, Saint Luc University Hospital, Brussels, Belgium Percutaneous endopyelotomy was one of the first minimally invasive surgical procedures to address a reconstructive operation. In patients with ureteropelvic junction (UPJ) obstruction the ultimate goal remains the relief of the obstruction in order to preserve renal function and reduce pain with minimal morbidity. Prior to the introduction of laparoscopic pyeloplasty, percutaneous endopyelotomy rapidly gained acceptance and became widely adopted in the management of UPJ obstruction, replacing open pyeloplasty [1]. However, being totally endoscopic, endopyelotomy can only address intrinsic factors of obstruction; extrinsic causes cannot be corrected. In UPJ obstruction, the renal pelvis is usually dilated or redundant. Classically, the volume should be reduced by resecting part of the wall, but this is not possible with a purely endoscopic procedure, neither redundancy of the renal pelvis. This probably explains its inferior success rate compared to pyeloplasty, especially when it is applied without selection [2–5]. As with many pioneering techniques, endopyelotomy has been superseded by newer techniques and is now less often performed (see Prognostic factors, patient selection, and results) [6–8]. It nevertheless retains its status as a landmark procedure, and could be regarded as one of the first natural orifice transluminal endoscopic surgeries (NOTES) to be routinely performed [7]. Preoperative evaluation of UPJ obstruction is mandatory with a view to documenting the following critical prognostic factors: the stricture (length, nature, and degree), the involved renoureteral unit (individual renal function, degree of hydronephrosis, remaining ureter), the presence of extrinsic factors (crossing vessels, bands), and the patient themselves (Box 30.1, Figure 30.1). Figure 30.1 (a) CT scan and (b) retrograde pyelogram showing right‐sided hydronephrosis secondary to UPJ obstruction. Preoperative decompression of the collecting system is advisable in totally obstructed cases, in case of active infection, or when there is a need to evaluate the function of the kidney. Tubular function recuperates in 10–15 days; glomerular function improves more slowly (up to three months). Despite its potential associated morbidity, we favor a small nephrostomy tube inserted under local anesthesia rather than a double‐J stent, which commonly induces an inflammatory reaction at the UPJ that may later interfere with healing. For percutaneous endopyelotomy we start with the patient positioned prone in a split‐legged position. A flexible cystoscopy is passed through the urethra into the bladder and a hydrophilic tipped guidewire is advanced up the affected side into the kidney. The cystoscope is then removed and a 5 Fr open‐ended catheter is advanced up into the renal pelvis and secured. A 16 Fr Foley catheter is placed into the bladder. If this maneuver fails, the endoscopic route should be abandoned, since further attempts to localize an impassable UPJ usually are unsuccessful and an unguided incision is dangerous and may result in total separation of the ureter. The best orientation for the incision is still a matter of debate. In a primary UPJ obstruction with no prior pyeloplasty, a lateral incision is made to avoid both a potential posterior and anterior crossing vessel [10]. In a patient who underwent a prior pyeloplasty and had a posterior crossing vessel displaced anteriorly, we prefer to make the incision posterolaterally. The incision is made through the entire thickness of the pelvic wall, the UPJ, and the narrow portion of the proximal ureter, and as far down as necessary to visualize a normal‐caliber lumen, essentially performing an endoureteropyelotomy. A significant advantage of the direct percutaneous approach is the possibility of careful visual inspection of the pelvic wall, looking for pulsation transmitted from significant adjacent crossing vessels. The second guidewire is advantageous to straighten and stiffen the ureter to be incised. Incision of the UPJ can be performed using a cold (straight or hooked) knife railroaded on the track, electric incision, or, more recently, the holmium laser. Equal success has been obtained with these different modalities. When the exact length of the abnormal ureter is in doubt, a dilation balloon is inserted over the second guidewire and is inflated with contrast under fluoroscopic control, with care being taken to correct any residual or additional narrowed areas. Prolonged stenting and drainage are deemed essential, although their exact duration is still a matter of controversy. A convenient drainage system consists of a 14/7 double‐J stent, commonly referred today as an “endopyelotomy” stent (Figure 30.2), straddling the incised UPJ. Other drainage techniques including the traditional 8 Fr double‐J stent have been used successfully, provided that extravasation is minimal and drainage is adequate. Our own practice has been to leave two traditional 7 Fr stents in parallel in an effort both to hold the UPJ widely open during the healing process and to provide maximum drainage. We typically do not leave a nephrostomy tube but a Foley catheter is placed to prevent reflux and further extravasation of urine through the endopyelotomy incision. In patients with a history of voiding dysfuction or a history of lower urinary tract symptoms, consideration to discharging them home with a Foley cather is made. The internal stent is removed under local anesthesia in the outpatient clinic after 4–6 weeks [1, 11, 12]. Figure 30.2 Endopyelotomy stent. The proximal end measures 14 Fr and the distal end measures 7 Fr in diameter.
Percutaneous Treatment of Ureteropelvic Junction Obstruction
Introduction
Preoperative management
Preoperative drainage
Antegrade endopyelotomy
Percutaneous endopyelotomy
If the catheter is placed with the patient in the supine position, then they should be repositioned prone on the table as for a classical percutaneous procedure Ideally, a posterior calyx is punctured and catheterized. A middle or superior calyx should be selected to secure an adequate working angle to the UPJ. The tract is dilated and the nephroscope is introduced. Secondary calculi are fragmented and extracted at this stage. The UPJ is easily identified by the protruding retrograde ureteral catheter. A second guidewire is introduced from above and down into the ureter. Streem describes placing the ureteral stent in an antegrade fashion prior to performing the incision using an acorn‐tip Bugbee. The UPJ and proximal ureter can often be seen to bulge into the renal pelvis, such that a subsequent endopyelotomy is equivalent to a ureteral meatotomy at the ureterovesical junction. Having a stent in place at the onset of the procedure helps to better define the UPJ, and also obviates concern about avulsing the UPJ during placement of a stent after the UPJ has been incised [9] (see Video 30.1).
Invagination technique
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