Postpercutaneous Nephrolithotomy Ureteropelvic Junction Obstruction

Abstract

Percutaneous endoscopic renal surgery such as percutaneous nephrolithotomy (PCNL) is a safe and effective treatment for patients with large and/or complex renal calculi. However, a unique set of complications can occur with this surgical approach that may involve the targeted kidney and surrounding structures. Renal collecting system obstruction after PCNL is rare, but may result from ureteral avulsion, stricture formation, transient mucosal edema, blood clot, or infundibular stenosis. Impaction of stone and trauma during PCNL could induce stricture formation and obstruction. Use of proper percutaneous and endoscopic techniques and instruments will help to reduce the chances of developing such strictures and obstruction.

Introduction

Percutaneous nephrolithotomy (PCNL) is considered as a standard of care in the treatment of staghorn and/or large-volume renal calculi. It is also used in the management of upper tract calculi refractory to other modalities, difficult lower pole stones, cystine urolithiasis, and calculi in anatomically abnormal kidneys.^1,2 PCNL is considered as a safe and well-tolerated procedure. However, like with any other surgical intervention, PCNL is associated with a specific set of complications.^3,4

PCNL has been widely accepted by urologists all over the world and this makes it important to standardize reporting of complications. There have been several classifications used for reporting surgical complications. One of the most widely accepted classification systems within surgery and urology is the one that was proposed by Clavien et al.⁵ The Clinical Research Office of the Endourological Society (CROES) PCNL study group adopted the Clavien–Dindo classification system for a large prospective cohort study of 5803 patients from 96 participating centers in 26 countries.⁶ The authors found that 20.5% of patients experienced one or more complications, the majority of which were Clavien–Dindo grade I (54%) with few life-threatening complications (0.5%) and two deaths (0.03%).

Renal collecting system obstruction after PCNL is rare, but may result from ureteral avulsion or stricture, transient mucosal edema, blood clot, or infundibular stenosis. Transient renal collecting system obstruction either caused by edema or blood clot often resolve without intervention or long-term sequelae. However, persistent renal collecting system obstruction is associated with ureteral stricture or avulsion, which can further lead to nephrocutaneous fistulae, hydronephrosis, or hydrocalix. Prolonged operative time, large stone burden, and extended postoperative nephrostomy tube drainage are known risk factors for persistent obstruction.⁷ We report a case of post-PCNL ureteropelvic junction (UPJ) obstruction with secondary calculi.

Case Report

A 65-year-old woman presented to the urologic services of the hospital with complaints of left flank pain, fever, and vomiting. She had previously undergone left PCNL 3 years ago for a 3.1 cm staghorn calculi. Urine examination revealed plenty of pus cells with numerous bacteria. Urine culture showed Escherichia coli. Ultrasonography showed a dilated pelvicaliceal system (PCS) on the left side with multiple calculi in the lower pole calix. A CT was done that showed a cluster of small calculi (8–10 in number) measuring 3–6 mm both in the anterior and posterior lower calices (Fig. 1a–d). Two other small calculi were seen in the renal pelvis. The left kidney showed moderate hydronephrosis. There was scarring at the UPJ with a focal bend of the ureter resulting in UPJ obstruction. The left kidney showed decreased renal function when compared with the right side. A 99mTc-DTPA (diethylene triamine pentaacetate) renal scan showed prompt perfusion of the left kidney with delayed and suboptimal cortical tracer extraction and delayed intrarenal transit time. The glomerular filtration rate was 23.2 mL/min on the left side and 55.5 mL/min on the right side (Fig. 2a, b).

FIG. 1.

(a–d) CT scan showing cluster of small calculi both in the anterior and posterior lower calices. Two other small calculi seen in the renal pelvis.

FIG. 2.

DTPA renogram showing the GFR of 23.2 mL/min on the left side and 55.5 mL/min on the right side. GFR, glomerular filtration rate.

The patient was prepared for a repeat PCNL. Initial retrograde pyeloureterogram showed a narrow UPJ with a small renal pelvis. A 0.038 inch guidewire was passed into the renal collecting system; however, dilatation of the narrow portion with Teflon dilators was not possible. The guidewire was left in place and a 5F ureteral catheter was passed into the ureter for instillation of contrast media (Fig. 3a, b). The patient was positioned for PCNL in the prone position. The PCS was punctured through the posterior middle calix and the nephroscope was introduced into the PCS after dilatation of the tract. The stones in lower calices and pelvis were cleared. The guidewire passed through the ureter into PCS was identified. Using it as a guide a posterior medial endopyelotomy was done using a hook electrode. The UPJ was dilated sufficiently and a silicon 6F ureteral Double-J stent was passed through the ureter into the bladder. A 14F nephrostomy was placed. Postoperatively the patient recovered well. The Double-J ureteral stent was removed after 6 weeks and a 99mTc-DTPA renogram repeated after 12 weeks, which showed adequate drainage. The patient has been advised close follow-up, with repeat ultrasonography every 3 months, and DTPA renogram every year for at least 3 years.

FIG. 3.

(a, b) Retrograde pyeloureterogram shows narrowing of the UPJ. A 0.038 inch guidewire was passed into the PCS. PCS, pelvicaliceal system; UPJ, ureteropelvic junction.

Discussion

UPJ obstruction after PCNL seems to be rare. Stricture after percutaneous renal surgery occurs in <1% of cases; the proximal ureter and the UPJ are the areas most commonly involved.⁸ Impaction of stone could induce stricture formation; however, in many cases it is the trauma during the procedure, including intracorporeal lithotripsy that is responsible for the stricture and obstruction. Patients having a urinary diversion and proximal ureteral calculi may be at increased risk for stricture formation owing to an intense inflammatory response (obliterative pyeloureteritis) that may occur. “Silent obstruction” from stricture formation after PCNL has been described, which emphasizes the need for routine postoperative imaging in patients to assess for this occurrence.⁸ The vast majority of patients can be managed effectively utilizing endourologic techniques such as endopyelotomy provided the stricture is <1.5 cm in length. Endopyelotomy can be performed either to the antegrade or retrograde route and it can be performed using either cold knife, electrocautery, or laser.⁹ Advantages of the antegrade approach over retrograde techniques include the ability to remove nonobstructing renal stones and to place a stent >8F across the incised UPJ.⁹ It is always recommended to visually inspect the strictured area for arterial pulsations. Open surgical or laparoscopic reconstruction may be necessary in patients with more extensive strictures or in those who fail an endoscopic approach. Prevention of such strictures is important. Use of proper percutaneous and endoscopic techniques and instruments will definitely reduce the chances of developing such strictures and obstruction.

Abbreviations Used

CT

computed tomography

PCNL

percutaneous nephrolithotomy

PCS

pelvicaliceal system

UPJ

ureteropelvic junction

Disclosure Statement

No competing financial interests exist.

Cite this article as: Nerli RB, Kadeli V, Deole S, Mishra A, Patil S, Ghagane SC, Hiremath MB, Dixit NS (2020) Postpercutaneous nephrolithotomy ureteropelvic junction obstruction, Journal of Endourology Case Reports 6:1, 13–15, DOI: 10.1089/cren.2019.0084.