Ureteropelvic Junction Obstruction

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Ureteropelvic junction (UPJ) obstruction is defined as an obstruction of the flow of urine from the renal pelvis to the proximal ureter. The condition is frequently encountered by both adult and pediatric urologists. Congenital abnormalities may be observed in both adults and children, but adults may also present with UPJ obstruction secondary to surgery or other disorders that can cause inflammation of the upper urinary tract.

The critical decision to be made in dealing with suspected UPJ obstruction is whether the radiologic findings correlate with the physiologic picture. In other words, severely dilated hydronephrotic kidneys may, in fact, be found to be draining well when studied appropriately. Defining the exact anatomy and function of these kidneys is crucial when evaluating and treating these patients.

The treatment strategies for UPJ obstruction have shifted significantly in the last several years. The gamut of current surgical treatments for UPJ obstruction includes the following:

While open pyeloplasty is still considered the criterion standard for treatment of UPJ obstruction in infants, laparoscopic pyeloplasty, with or without robotic assistance, is the treatment of choice in older children and in most adults.^[1]

UPJ obstruction is the most common cause of neonatal and antenatal hydronephrosis, occurring in one per 1500 live births. Prior to the use of prenatal ultrasonography, most patients with UPJ obstruction presented with pain, hematuria, urosepsis, failure to thrive, or a palpable mass. With the enhanced ability and availability of prenatal ultrasonography, urologic abnormalities are being diagnosed earlier and more frequently. Fifty percent of patients diagnosed with antenatal hydronephrosis are eventually diagnosed with UPJ obstruction upon further workup.

Initially, most children are treated conservatively and monitored closely. Intervention is indicated in the event of significantly impaired renal drainage or poor renal growth.

UPJ obstruction is defined as an obstruction of the flow of urine from the renal pelvis to the proximal ureter. The resultant back pressure within the renal pelvis may lead to progressive renal damage and deterioration.

UPJ obstruction presents most frequently in childhood, but adult and elderly individuals can also present with a primary obstructive lesion. In adults, other etiologies for ureteral obstruction must be considered, including stones, ureteral compression due to extrinsic processes, retroperitoneal fibrosis, and other inflammatory processes.

Epidemiologic features of UPJ obstruction are as follows:

Ultrasonography reveals fetal upper urinary tract dilatation in approximately one in 100 pregnancies; however, only one in 500 of those infants are later diagnosed with significant urologic problems

UPJ obstruction is found in approximately 50% of patients diagnosed with antenatal hydronephrosis

The male-to-female ratio of UPJ obstruction is 3-4:1

In general, the left kidney is more commonly affected than the right kidney

UPJ obstruction is less common in adults than in children but is not rare in either population

UPJ obstruction is bilateral in 10% of cases

Possible etiologies for UPJ obstruction include the following:

Intrinsic obstruction may result from stenosis due to scarring of ureteral valves.

Ureteral hypoplasia may result in abnormal peristalsis through the UPJ. Asymmetry of ureteral wall musculature may inhibit the natural peristaltic emptying of the renal pelvis into the ureter.

An abnormal or high insertion of the ureter into the renal pelvis may alter the configuration and impair drainage of urine. This may be an effect rather than a cause because the two etiologies mentioned above may manifest as a high-insertion variant seen on imaging studies.

Crossing lower-pole renal vessel(s) or entrapment of the ureter by a vessel can block urinary flow down the ureter. Vessels that wrap around the UPJ may be associated with obstruction or may be a product of renal dilatation and hydronephrosis that distorts renal vascular architecture.

Rotation of the kidney (eg, renal ectopy) and renal hypermobility can cause intermittent obstruction that is solely dependent on the position of the kidney relative to the ureter. This was once a very popular diagnosis; however, the other etiologies mentioned above are more prevalent today, and this cause is particularly rare.

Secondary UPJ obstruction can be caused by prior surgical intervention to treat other disorders (eg, renal stone disease) or failed repair of a primary UPJ obstruction. This obstructive lesion is usually secondary to ureteral-wall and periureteral scar formation.

All of the above abnormalities impair drainage of urine from the kidney into the ureter, resulting in elevated intrarenal back pressure, dilatation of the collecting system, and hydronephrosis.

Scanning electron microscopy studies using 3-dimensional techniques have shown that normal elasticity and distension of the renal pelvis are impaired secondary to rigid collagen bundling. Increased collagen deposition between smooth muscle cells results in wider cell-to-cell and nerve-to-cell distances. Neural depletion has also been reported. In addition, immunohistochemical studies have shown decreased neuronal markers and nerve growth factors within the smooth muscle layer, thus impeding peristalsis.

In the rat model, acute obstruction resulted in increased levels of angiotensin 11 and increased transforming growth factor–β expression, resulting in pathological deposition of extracellular matrix, which may be one mechanism that leads to obstruction.

Neonates may present with hydronephrosis. Older children may present with urinary tract infection (UTI), a flank mass, or intermittent flank pain secondary to a primary UPJ obstruction. Hematuria may also be a presenting sign if obstruction is associated with infection.

Adults with UPJ obstruction can present with various symptoms, including back and flank pain, UTI, and/or pyelonephritis. A detailed history may reveal that the pain correlates with periods of increased fluid intake or ingestion of a food with diuretic properties (ie, Dietl crisis).

The goals in treating patients with ureteropelvic junction (UPJ) obstruction are to improve renal drainage and to maintain or improve renal function.

As mentioned above, dilatation of the intrarenal collecting system or hydronephrosis does not necessarily imply obstruction. Specifically in children, renal pelvic dilatation should be monitored with serial imaging to assess for changes in dilatation, renal parenchymal thickness and/or the presence of scarring, and function. Surgical repair is indicated upon a significant differential on serial imaging or progressive deterioration of renal function.

Using this algorithm, patients with hydronephrosis are monitored closely with renal ultrasonography and nuclear medicine renography every 3-6 months. Similarly, in adults, repair is recommended if nuclear medicine renal scan or intravenous pyelography (IVP) reveals ureteral obstruction.

The evaluation of an obstructed ureteropelvic junction (UPJ) requires information about ureteral and surrounding anatomy, renal position and ectopy, associated vasculature, and renal function. Prior to surgical intervention, the surgeon frequently evaluates for renal position/ectopy, mobility, and UPJ anatomy, such as high-insertion variants versus annular stricture variants.

The major vascular supply of the UPJ comes from branches of the renal artery. These vessels usually lie in an anteromedial location in relation to the proximal ureter. Aberrant polar vessels may also be associated with the renal pelvis, causing compression and obstruction of the collecting system. These vessels arise from either the renal artery from a position proximal to the main intrarenal branching site or directly from the aorta. They can surround the UPJ and can be associated with obstruction, or they may be aberrantly positioned secondary to increasing hydronephrosis.

An endopyelotomy refers to an endoscopic incision of the UPJ, performed to create a more funneled drainage system and to bring the UPJ more dependent or caudad below areas of pathology.

The vascular anatomy at the UPJ becomes crucial during an endopyelotomy. The renal collecting system may be accessed percutaneously (antegrade) or in a retrograde fashion via passage of a ureteroscope through the urethra, bladder, and ureter in order to access the obstruction and to perform an incision. While most associated UPJ vessels lie in the anteromedial plane, accessory vessels may lie posteriorly or laterally. If all endoscopic incisions are made in the posterior-lateral plane, intraoperative hemorrhage may occur. For this reason, a comprehensive vascular evaluation with intraoperative endoluminal ultrasonography, preoperative CT scanning, or MRI with vascular reconstruction is recommended prior to this form of treatment.

Multidetector CT scanning with 3-dimensional reconstruction can be particularly helpful in establishing the anatomy of UPJ obstruction, revealing an intrinsic or high-insertion UPJ. Crossing vessels and their relationship to the ureter of the UPJ can also be evaluated. The location of these vessels and their possible contribution to renal obstruction can help the surgeon decide whether endopyelotomy, open pyeloplasty, or laparoscopic pyeloplasty would be the most effective treatment modality.

When an open or laparoscopic pyeloplasty is performed, an accurate understanding of the vascular anatomy allows the surgeon to preserve the accessory renal vessels and to redirect them if the surgeon feels that they contribute to the obstruction. If an endopyelotomy is planned, this information can guide the surgeon in directing the endopyelotomy incision away from crossing vessels. CT scanning in combination with 3-phase and 3-dimensional contrast imaging yields a reported sensitivity of 75%-97% in revealing crossing vessels. El-Nahas et al reported that CT scanning yielded a sensitivity of 97%, specificity of 92%, and accuracy of 96% in detecting crossing vessels associated with UPJ obstruction.^[2]

Retrograde pyelography at the time of surgery is often used to estimate the length of the stricture and the amount of pelvis/ureter that needs to be excised at the time of the pyeloplasty to create a dependent funnel.

Symons SJ, Bhirud PS, Jain V, Shetty AS, Desai MR. Laparoscopic pyeloplasty: our new gold standard. J Endourol. 2009 Mar. 23(3):463-7. [Medline].

El-Nahas AR, Abou-El-Ghar M, Shoma AM, Eraky I, El-Kenawy MR, El-Kappany H. Role of multiphasic helical computed tomography in planning surgical treatment for pelvi-ureteric junction obstruction. BJU Int. 2004 Sep. 94(4):582-7. [Medline].

Conway JJ, Maizels M. The “well tempered” diuretic renogram: a standard method to examine the asymptomatic neonate with hydronephrosis or hydroureteronephrosis. A report from combined meetings of The Society for Fetal Urology and members of The Pediatric Nuclear Medicine C. J Nucl Med. 1992 Nov. 33(11):2047-51. [Medline].

von Rundstedt FC, Scovell JM, Bian SX, Lee D, Mayer WA, Link RE. Percent of Tracer Clearance at 40 Minutes in MAG3 Renal Scans Is More Sensitive Than T_1/2 for Symptomatic Ureteropelvic Junction Obstruction. Urology. 2017 May. 103:245-250. [Medline].

Nishi M, Matsumoto K, Fujita T, Iwamura M. Improvement in Renal Function and Symptoms of Patients Treated with Laparoscopic Pyeloplasty for Ureteropelvic Junction Obstruction with Less Than 20% Split Renal Function. J Endourol. 2016 Nov. 30 (11):1214-1218. [Medline].

Singla N, Lay AH, Cadeddu JA. Poor split renal function and age in adult patients with ureteropelvic junction obstruction do not impact functional outcomes of pyeloplasty. Can J Urol. 2016 Oct. 23 (5):8457-8464. [Medline].

Li XD, Wu YP, Wei Y, Chen SH, Zheng QS, Cai H, et al. Predictors of Recoverability of Renal Function after Pyeloplasty in Adults with Ureteropelvic Junction Obstruction. Urol Int. 2018 Jan 18. [Medline].

Kim S, Jacob JS, Kim DC, Rivera R, Lim RP, Lee VS. Time-resolved dynamic contrast-enhanced MR urography for the evaluation of ureteral peristalsis: initial experience. J Magn Reson Imaging. 2008 Nov. 28(5):1293-8. [Medline].

Ritter L, Götz G, Sorge I, Lehnert T, Hirsch FW, Bühligen U, et al. Significance of MR Angiography in the Diagnosis of Aberrant Renal Arteries as the Cause of Ureteropelvic Junction Obstruction in Children. Rofo. 2015 Jan. 187(1):42-48. [Medline].

Strother MC, Mucksavage P. Minimally Invasive Techniques for the Management of Adult UPJ Obstruction. Curr Urol Rep. 2016 May. 17 (5):39. [Medline].

Sorokin I, O’Malley RL, McCandless BK, Kaufman RP Jr. Successful Outcomes in Robot-Assisted Laparoscopic Pyeloplasty Using a Unidirectional Barbed Suture. J Endourol. 2016 Jun. 30 (6):660-4. [Medline].

Jacobs BL, Lai JC, Seelam R, Hanley JM, Wolf JS Jr, Hollenbeck BK, et al. The Comparative Effectiveness of Treatments for Ureteropelvic Junction Obstruction. Urology. 2017 Sep 21. [Medline].

Parente A, Angulo JM, Burgos L, Romero RM, Rivas S, Ortiz R. Percutaneous Endopyelotomy over High Pressure Balloon for Recurrent Ureteropelvic Junction Obstruction in Children. J Urol. 2015 Jul. 194 (1):184-9. [Medline].

Gill IS, Desai MM, Kaouk JH, Wani K, Desai MR. Percutaneous endopyeloplasty: description of new technique. J Urol. 2002 Nov. 168(5):2097-102. [Medline].

Shapiro EY, Cho JS, Srinivasan A, Seideman CA, Huckabay CP, Andonian S, et al. Long-term follow-up for salvage laparoscopic pyeloplasty after failed open pyeloplasty. Urology. 2009 Jan. 73(1):115-8. [Medline].

Singh V, Sinha RJ, Gupta DK, Kumar V, Pandey M, Akhtar A. Prospective randomized comparison between transperitoneal laparoscopic pyeloplasty and retroperitoneoscopic pyeloplasty for primary ureteropelvic junction obstruction. JSLS. 2014 Jul. 18(3):[Medline]. [Full Text].

Casale P. Robotic pyeloplasty in the pediatric population. Curr Urol Rep. 2009 Jan. 10(1):55-9. [Medline].

Casale P. Robotic pyeloplasty in the pediatric population. Curr Opin Urol. 2009 Jan. 19(1):97-101. [Medline].

Tugcu V, Sönmezay E, Ilbey YO, Polat H, Tasci AI. Transperitoneal laparoendoscopic single-site pyeloplasty: initial experiences. J Endourol. 2010 Dec. 24(12):2023-7. [Medline].

Stein RJ, Berger AK, Brandina R, et al. Laparoendoscopic single-site pyeloplasty: a comparison with the standard laparoscopic technique. BJU Int. 2011 Mar. 107(5):811-5. [Medline].

Seideman CA, Tan YK, Faddegon S, Park SK, Best SL, Cadeddu JA, et al. Robot-assisted laparoendoscopic single-site pyeloplasty: technique using the da Vinci Si robotic platform. J Endourol. 2012 Aug. 26(8):971-4. [Medline].

Isoyama T, Iwamoto H, Inoue S, Morizane S, Hinata N, Yao A, et al. Hydronephrosis after retroperitoneal laparoscopic dismembered Anderson-Hynes pyeloplasty in adult patients with ureteropelvic junction obstruction: A longitudinal analysis. Cent European J Urol. 2014. 67 (1):101-5. [Medline].

Sepilveda JC, Rodó Salas J, Mañé S, Tarrado X, Morales L. [Evolution of pre and postoperative renographic parameters in pyeloreteral juntion obstruction syndrome]. Cir Pediatr. 2004 Oct. 17 (4):179-84. [Medline].

Molina CA, Facincani I, Muglia VF, Araujo WM, Cassini MF, Tucci S Jr. Postnatal evaluation of intrauterine hydronephrosis due to ureteropelvic junction obstruction. Acta Cir Bras. 2013. 28 Suppl 1:33-6. [Medline].

Bagley DH, Liu JB. Endoureteral sonography to define the anatomy of the obstructed ureteropelvic junction. Urol Clin North Am. 1998 May. 25(2):271-9. [Medline].

Baniel J, Livne PM, Savir A. Dismembered pyeloplasty in children with and without stents. Eur Urol. 1996. 30(3):400-2. [Medline].

Bartoli F, Penza R, Aceto G, et al. Urinary epidermal growth factor, monocyte chemotactic protein-1, and ß2-microglobulin in children with ureteropelvic junction obstruction. J Pediatr Surg. 2011 Mar. 46(3):530-6. [Medline].

Boylu U, Oommen M, Lee BR, Thomas R. Ureteropelvic junction obstruction secondary to crossing vessels-to transpose or not? The robotic experience. J Urol. 2009 Apr. 181(4):1751-5. [Medline].

Casale P, Grady RW, Joyner BD, Zeltser IS, Figueroa TE, Mitchell ME. Comparison of dismembered and nondismembered laparoscopic pyeloplasty in the pediatric patient. J Endourol. 2004 Nov. 18(9):875-8. [Medline].

Chow GK, Geisinger MA, Streem SB. Endopyelotomy outcome as a function of high versus dependent ureteral insertion. Urology. 1999 Dec. 54(6):999-1002. [Medline].

el-Nahas AR, Shoma AM, Eraky I, el-Kenawy MR, el-Kappany HA. Prospective, randomized comparison of ureteroscopic endopyelotomy using holmium:YAG laser and balloon catheter. J Urol. 2006 Feb. 175(2):614-8; discussion 618. [Medline].

El-Sherbiny MT, Mousa OM, Shokeir AA, Ghoneim MA. Role of urinary transforming growth factor-beta1 concentration in the diagnosis of upper urinary tract obstruction in children. J Urol. 2002 Oct. 168(4 Pt 2):1798-800. [Medline].

Figenshau RS, Clayman RV. Endourologic options for management of ureteropelvic junction obstruction in the pediatric patient. Urol Clin North Am. 1998 May. 25(2):199-209. [Medline].

Frauscher F, Janetschek G, Helweg G. Crossing vessels at the ureteropelvic junction: detection with contrast- enhanced color Doppler imaging. Radiology. 1999 Mar. 210(3):727-31. [Medline].

Jabbour ME, Goldfischer ER, Klima WJ. Endopyelotomy after failed pyeloplasty: the long-term results. J Urol. 1998 Sep. 160(3 Pt 1):690-2; discussion 692-3. [Medline].

Johnston JH, Evans JP, Glassberg KI. Pelvic hydronephrosis in children: a review of 219 personal cases. J Urol. 1977 Jan. 117(1):97-101. [Medline].

Kajbafzadeh AM, Elmi A, Talab SS, Emami H, Esfahani SA, Saeedi P. Urinary and serum carbohydrate antigen 19-9 as a biomarker in ureteropelvic junction obstruction in children. J Urol. 2010 Jun. 183(6):2353-60. [Medline].

Kumar R, Kapoor R, Mandhani A. Optimum duration of splinting after endopyelotomy. J Endourol. 1999 Mar. 13(2):89-92. [Medline].

Lee RS, Retik AB, Borer JG, Peters CA. Pediatric robot assisted laparoscopic dismembered pyeloplasty: comparison with a cohort of open surgery. J Urol. 2006 Feb. 175(2):683-7; discussion 687. [Medline].

Lopez-Pujals A, Leveillee RJ, Wong C. Application of strict radiologic criteria to define success in laparoscopic pyeloplasty. J Endourol. 2004 Oct. 18(8):756-60. [Medline].

Matlaga BR, Shah OD, Singh D, Streem SB, Assimos DG. Ureterocalicostomy: a contemporary experience. Urology. 2005 Jan. 65(1):42-4. [Medline].

McDaniel BB, Jones RA, Scherz H, Kirsch AJ, Little SB, Grattan-Smith JD. Dynamic contrast-enhanced MR urography in the evaluation of pediatric hydronephrosis: Part 2, anatomic and functional assessment of uteropelvic junction obstruction. AJR Am J Roentgenol. 2005 Dec. 185(6):1608-14. [Medline].

Mitterberger M, Pinggera GM, Neururer R, Peschel R, Colleselli D, Aigner F, et al. Comparison of contrast-enhanced color Doppler imaging (CDI), computed tomography (CT), and magnetic resonance imaging (MRI) for the detection of crossing vessels in patients with ureteropelvic junction obstruction (UPJO). Eur Urol. 2008 Jun. 53(6):1254-60. [Medline].

Murakumo M, Nonomura K, Yamashita T, Ushiki T, Abe K, Koyanagi T. Structural changes of collagen components and diminution of nerves in congenital ureteropelvic junction obstruction. J Urol. 1997 May. 157(5):1963-8. [Medline].

Niemczyk P, Krisch EB, Zeiger L. Use of diuretic renogram in evaluation of patients before and after endopyelotomy. Urology. 1999 Feb. 53(2):271-5. [Medline].

Park JM, Bloom DA. The pathophysiology of UPJ obstruction. Current concepts. Urol Clin North Am. 1998 May. 25(2):161-9. [Medline].

Patel V. Robotic-assisted laparoscopic dismembered pyeloplasty. Urology. 2005 Jul. 66(1):45-9. [Medline].

Reddy PP, Mandell J. Prenatal diagnosis. Therapeutic implications. Urol Clin North Am. 1998 May. 25(2):171-80. [Medline].

Richstone L, Seideman CA, Reggio E, Bluebond-Langner R, Pinto PA, Trock B, et al. Pathologic Findings in Patients With Ureteropelvic Junction Obstruction and Crossing Vessels. Urology. 2009 Feb 2. [Medline].

Rooks VJ, Lebowitz RL. Extrinsic ureteropelvic junction obstruction from a crossing renal vessel: demography and imaging. Pediatr Radiol. 2001 Feb. 31(2):120-4. [Medline].

Shalhav AL, Giusti G, Elbahnasy AM. Adult endopyelotomy: impact of etiology and antegrade versus retrograde approach on outcome. J Urol. 1998 Sep. 160(3 Pt 1):685-9. [Medline].

Siddiq FM, Leveillee RJ, Villicana P, Bird VG. Computer-assisted laparoscopic pyeloplasty: University of Miami experience with the daVinci Surgical System. J Endourol. 2005 Apr. 19(3):387-92. [Medline].

Smith AD, Horgan JD. Endopyelotomy and Pyeloplasty. Clinical Urology. Philadelphia, Pa: JB Lippincott; 1994. 433-43.

Thomas DF. Fetal uropathy. Br J Urol. 1990 Sep. 66(3):225-31. [Medline].

Wang Y, Puri P, Hassan J, Miyakita H, Reen DJ. Abnormal innervation and altered nerve growth factor messenger ribonucleic acid expression in ureteropelvic junction obstruction. J Urol. 1995 Aug. 154(2 Pt 2):679-83. [Medline].

Yurkanin JP, Fuchs GJ. Laparoscopic dismembered pyeloureteroplasty: a single institution’s 3-year experience. J Endourol. 2004 Oct. 18(8):765-9. [Medline].

Mizuno K, Kojima Y, Kurokawa S, Kamisawa H, Nishio H, Moritoki Y, et al. Robot-assisted laparoscopic pyeloplasty for ureteropelvic junction obstruction: comparison between pediatric and adult patients-Japanese series. J Robot Surg. 2017 Jun. 11 (2):151-157. [Medline].

Michael Grasso, III, MD Professor and Vice Chairman, Department of Urology, New York Medical College; Director, Living Related Kidney Transplantation, Westchester Medical Center; Director of Endourology, Lenox Hill Hospital

Michael Grasso, III, MD is a member of the following medical societies: American Medical Association, American Urological Association, Endourological Society, International Society of Urology, Medical Society of the State of New York, National Kidney Foundation, Society of Laparoendoscopic Surgeons

Disclosure: Received consulting fee from Karl Storz Endoscopy for consulting.

Jacob H Cohen, MD, MPH Fellow in Endourology, Lenox Hill Hospital