Pelvic urethral junction obstruction

1. Pelvic urethral junction obstruction Dec 2015

2. Pelvicurethral Junction Obstruction (PUJO) • PUJO: Probably commonest congenital abnormality of ureter with reported incidence of about 5/100000 of population/year • One of commonest form of urinary tract obstruction seen in children • Occurs more often in males than females (5:2 ratio) & when unilateral, more commonly affects left side (5:2 ratio) • 10-15% of cases (Bilateral obstruction) & commoner in infants British Journal of Urology (1997), 80, 365–372.

3. PUJO • Most PUJO is probably congenital, it often presents later in life • PUJO can be diagnosed during investigation of urological symptoms or imaging for other reasons BJU International. 2012; 110: 446-448.

4. PUJO • Usually appears spontaneously, but clustering of cases in some families suggests that there may be genetic predisposition • Often associated with other renal abnormalities, such as contralateral renal agenesis, ectopic position, duplication of the collecting system, multicystic dysplastic kidney and horseshoe kidney British Journal of Urology (1997), 80, 365–372.

5. 2 types of PUJO • Koffdescribed 2types of PUJO: Intrinsic & Extrinsic • Intrinsic type classically known as “adynamic” segment: Defective peristalsis of urine at level PUJ leads to obstruction & hydronephrosis • Extrinsic type: Mechanical factors such as crossing vessels, adhesive bands, arterio-venousmalformations & fetal folds have been described to cause PUJO • Very rarely renal structural abnormalities such as horseshoe kidney & malrotation of kidneys present with PUJO Eur J Pediatr Surg 2012; 22: 279–282.

6. Bimodal age of presentation Aust N Z J Surg. 1982; 52(2): 198-202.

7. Major presenting compliant Aust N Z J Surg. 1982; 52(2): 198-202.

8. Colossal hydronephrosis caused by PUJO BMJ Case Reports 2011; doi:10.1136/bcr.10.2011.4913.

9. Colossal hydronephrosis caused by PUJO BMJ Case Reports 2011; doi:10.1136/bcr.10.2011.4913.

10. Diagnosis: Laboratory investigations • All patients with possible ureteropelvic junction (UPJ) obstruction should be evaluated with following lab studies: • CBC • Coagulation profile • Electrolyte levels • Renal function assessment: BUN & serum creatinine levels • Urine culture Medscape 2015.

11. Diagnosis: Imaging Studies • Neonates who present with hydronephrosis should be fully evaluated with voiding cystourethrography (VCUG; to rule out vesicoureteral reflux) & renal ultrasonography soon after birth • These patients should also be placed on prophylactic antibiotics to prevent UTIs, especially while diagnostic imaging is being performed Medscape 2015.

12. Intraluminal sonogram of ureteropelvic junction obstruction demonstrating multiple crossing vessels Medscape 2015.

13. Diagnosis: Imaging Studies • If renal USG demonstrates hydronephrosis without reflux on VCUG, a diuretic renal scan (mercaptotriglycylglycine [MAG-3], diethylenetriamine [DTPA], or dimercaptosuccinic acid [DMSA]) should be performed to quantify relative renal function & to define extent of obstruction • Renal ultrasonography and VCUG are performed in children with suspected UPJ obstruction Medscape 2015.

14. Diagnosis: Imaging Studies • Historically, intravenous pyelography (IVP) was used to evaluate patients with possible UPJ obstruction • However, in evaluation of a child with hydronephrotic kidney, diuretic renography has taken place of IVP • Benefits of diuretic renography are that iodine-based intravenous contrast is not used, radiation exposure is minimal & renal function can be better quantified • Disadvantage of nuclear medicine scan: Insight into renal anatomy is not obtained Medscape 2015.

15. Diagnosis: Imaging Studies • 1992, Society for Fetal Urology & PediatricNuclear Medicine Council published guidelines for "Well-Tempered Diuresis Renogram.“ • Standardized protocols for hydration, radiopharmaceuticals, bladder catheterization, diuretic dose, timing of diuretic & determination of clearance half-time (T 1/2) have been established • Functionally significant obstruction is often diagnosed with diuretic renal scanning • Conventional renographic criteria include a flat or rising washout curve after diuretic with T 1/2 of > 20 minutes & differential function of < 40. Differential function is important in determining need for intervention, especially in asymptomatic patients & in selecting appropriate treatment (pyeloplasty vs nephrectomy). Poorly functioning kidneys (< 10%) are often best treated with nephrectomy Medscape 2015.

16. Diagnosis: Imaging Studies • Nuclear medicine scanning is also used to assess outcomes after surgical intervention. • Evaluation of ureteral anatomy is difficult with nuclear medicine renal scanning • In adult patients, IVP is more commonly used to outline this anatomy & can often replace nuclear medicine scanning altogether Medscape 2015.

17. Intravenous pyelogram demonstrating ureteropelvic junction obstruction with dilatation of the collecting system and lack of excretion of contrast. Retrograde pyelogram demonstrating ureteropelvic junction obstruction secondary to annular stricture. Retrograde pyelogram demonstrating ureteropelvic junction obstruction secondary to crossing vessels

18. Diagnosis: Imaging Studies • Multidetector computed tomography (CT) scanning with 3-dimensional reconstruction may be used to help establish anatomy of UPJ obstruction & associated vessels • In children, retrograde ureteropyelography is sometimes performed to define entire ureter just prior to surgical repair • Contrast-enhanced color Doppler imaging is recommended by some as useful imaging modality for detection of crossing vessels in patients with UPJ obstruction Medscape 2015.

19. Diagnosis: Imaging Studies • Dynamic contrast-enhanced magnetic resonance urography (MRU) is latest imaging modality used in assessing UPJ obstruction • In children, this study offers advantages of no radiation exposure & excellent anatomical and functional details with single study • Study also provides details of renal vasculature, renal pelvis anatomy, location of crossing vessels, renal cortical scarring & ureteral fetal folds in proximal ureter Medscape 2015.

20. Diagnosis: Imaging Studies • Recent criteria for diagnosis of UPJ obstruction on MRU include fluid levels on delayed contrast-enhanced scans & presence of swirling contrast material on dynamic images • MRU using time-resolved, data-sharing 3-dimensional contrast-enhanced technique can demonstrate ureteral peristalsis & permits quantification of ureteral peristaltic frequency Medscape 2015.

21. Diagnosis: Imaging Studies • Contrast-enhanced magnetic resonance angiography (MRA) had a sensitivity of 85%, a specificity of 80%, and a positive predictive value of 0.8 for diagnosis of aberrant & obstructing renal arteries in a retrospective study of 19 pediatric patients with UPJ obstruction Medscape 2015.

22. MRI in evaluation of PUJO: All-in-one approach • Objective: • To study ability of comprehensive MRI to replace multiple imaging methods in evaluation of patients with PUJO • Patients & Methods: • 46 consecutive patients (22 male &24 females; mean age: 31.6 yrs) with symptomatic primary PUJO • All had comprehensive MRI, including MR urography (MRU), dynamic MRI &MR angiography (MRA) BJU Int. 2007; 99: 641-645.

23. MRI in evaluation of PUJO: All-in-one approach • Patients & Methods: • Morphological results of MRU were compared with that of renal ultrasonography or intravenous urography, while anatomical results of MRA were compared with operative findings • A correlation between MR clearance & radioisotope clearance was done using linear regression analysis BJU Int. 2007; 99: 641-645.

24. MRI in evaluation of PUJO: All-in-one approach • Results: • MRU: Morphology of collecting system in all patients& ureter below PUJ in 31 of 46 (67%), but renal stones were missed in 3 of 10 patients • MRA: Crossing vessels in 22 patients (48%) • Strong correlation between MR clearance & radioisotope clearance • MRI: 35 patients (19 with crossing vessels & 16 with marked hydronephrosis) had pyeloplasty& 11 had endopyelotomy BJU Int. 2007; 99: 641-645.

25. MRI in evaluation of PUJO: All-in-one approach • Results: • Findings during pyeloplastyshowed 1 false-negative & 1 false-positive result of preoperative MRI • Sensitivity, specificity & accuracy of MRA: 95%, 94% and 94%, respectively • Outcome was successful in 44 (96%) patients • 1 failure after pyeloplasty was managed with endopyelotomy& other was treated with pyeloplasty after endopyelotomy BJU Int. 2007; 99: 641-645.

26. MRI in evaluation of PUJO: All-in-one approach Gadodiamide-enhanced MRU shows mild left hydronephrosis with filling defect at PUJ secondary to a crossing vessel BJU Int. 2007; 99: 641-645.

27. A. Gadodiamide-enhanced renal MRA shows an artery (arrow) arising from aorta & crossing dilated non-opacified left renal pelvis to lower pole. B., T2-weighted static MRU of the same patient shows moderate left hydronephrosis with ballooned extrarenalpelvis BJU Int. 2007; 99: 641-645.

28. dMRItime-intensity curve shows obstructed pattern • Conclusion: • Comprehensive MRI is a valuable & accurate single-imaging method for evaluating patients with PUJO BJU Int. 2007; 99: 641-645.

29. Diagnostic Procedures • When workup results are equivocal, a Whitaker antegrade pressure-flow study may be performed to further evaluate for UPJ obstruction • This test begins with placement of small-diameter nephrostomy tube through back & directly into kidney • Dilute contrast medium is instilled & intrarenal collecting system is pressure-monitored • Under fluoroscopy, UPJ is assessed & drainage through this segment is defined Medscape 2015.

30. Diagnostic Procedures • While function cannot be assessed, relative resistance & pressure within renal pelvis can be measured • High intrarenal pressures define obstruction, while low pressures in presence of hydronephrosis are consistent with normal variance • This is particularly useful in large dilated systems in which renal pelvis must be completely full prior to drainage assessment • In this setting, nuclear medicine scanning can yield false-positive results Medscape 2015.

31. Indications to Relieve Obstruction • Ureteral obstruction that is symptomatic, accompanied by fever, complicated by undrained infection, or determined to be high grade, bilateral, or inducing renal failure warrants immediate drainage of affected renal unit • Indications for the relief of urinary tract obstruction Wein: Campbell-Walsh Urology, 9th ed. 2007.

32. Management of PUJO: Debatable subject for urologists BJU International. 2012; 110: 446-448.

33. Surgical intervention to treat obstructed UPJ is warranted, especially upon deterioration of renal function Principles of surgical repair, as initially described by Foley, include following: Formation of a funnel Dependent drainage Watertight anastomosis Tension-free anastomosis Medscape 2015.

34. Surgical Treatment • Surgical management of PUJO>> changed considerably over past 20 yrs • Traditionally, open pyeloplasty has been considered to be gold standard for treatment of PUJO with success rates of up to 95% • However, procedure requires loin incision & so is associated with prolonged recovery time European Urology 48 (2005) 973–977.

35. Surgical Treatment: Endopyelotomy • Endopyelotomybecame popular in 1980’s & 1990’s as minimally invasive technique with low complication rates, relatively short operating times & quick recovery • Success rates: 63% to 93% in well-selected patients • Higher success rates have been quoted in those patients with small pelvis & in whom no crossing vessels are present European Urology 48 (2005) 973–977.

36. Surgical Treatment: Laparascopypyeloplasty • Since end of last decade, laparoscopic pyeloplasty has become increasingly popular • Success rates: 87–100% • Procedure allows: • Identification of crossing vessels • Excision of diseased pelvi-ureteric junction plus or minus a reduction pyeloplasty& • Watertight anastomosis European Urology 48 (2005) 973–977.

37. Surgical Treatment: Laparascopypyeloplasty • Analgesic requirements, hospital stay & recovery period are considerably reduced compared to open procedure • Procedure requires considerable skill, has marked learning curve & involves longer operating times as compared with open and minimally invasive techniques • Can be performed via retroperitoneal/ transperitonealapproach • Equivalent success rates have been quoted in literature European Urology 48 (2005) 973–977.

38. Surgical Treatment: In Children • In children, procedure of choice is Anderson-Hynes dismembered pyeloplasty • Approach may be performed through flank, dorsal lumbotomy, or anterior extraperitonealtechnique • Laparoscopy has gained increasing acceptance in pediatric surgery & is often used to perform pyeloplasties in children Medscape 2015.

39. Surgical Treatment: In Children • In many cases, laparoscopic pyeloplasty is technically unfeasible in very small children & infants because of space constraints • Using this method, obstructed segment is completely resected, with reanastomosis of renal pelvis & ureter in dependent funneledfashion • Decision of whether to use ureteral stent transiently during initial healing process is based on personal preference of surgeon • Success rate of dismembered pyeloplasty for treating obstructed UPJ exceeds 95% Medscape 2015.

40. Anderson–Hynes dismembered pyeloplasty Nature Reviews Urology 11, 629–638 (2014).

41. Surgical treatment, i.e. pyeloplasty (laparoscopic & to lesser extent open pyeloplasty) remains ‘ gold standard ’ treatment for patients with PUJO if they are significantly symptomatic or if their renal function deteriorates on renogram - BJU International. 2012; 110: 446-448.

42. Treatment options for PUJO: implications for practice & training British Journal of Urology (1997), 80, 365–372.

43. Traditional Open Surgical Methods • Traditional open surgical methods for relief of PUJ obstruction are associated with success rate of 80-90% • However, this is usually achieved at expense of painful wound, period of 6–12 weeks until full activities can be resumed & unsightly scar • Occasionally, wound itself produces morbidity, in form of chronic pain or herniation • In recognition of these unwanted consequences of open renal surgery, techniques have been developed for treatment of PUJ obstruction which require either small or no incision British Journal of Urology (1997), 80, 365–372.

44. Balloon dilatation • Initial attempts at percutaneous treatment of PUJO were made with balloon catheters developed for treatment of occlusive coronary artery disease • Technique: • Gruntzigballoon catheter, whose deformation characteristics make it superior to conventional balloon catheters, is advanced over guidewire until it is seen to straddle PUJ on fluoroscopy • Failure to negotiate guidewire through narrowed PUJ using either retrograde or antegrade approach, requires procedure to be abandoned British Journal of Urology (1997), 80, 365–372.

45. Balloon dilatation: Technique • Balloon is then inflated until ‘waist’ (indicating site of obstruction) disappears & retrograde ureterography shows extravasation of contrast medium • Placement of double-pigtailstentensuresupper tract drainage, reducessubsequent urine extravasation & fibrosis, and is thought to be ‘a key factor in maintaining patency of dilated area’ British Journal of Urology (1997), 80, 365–372.

46. Balloon dilating catheter inflated across obstructed PUJ

47. Balloon dilatation: Results • As with balloon dilatation of ureteric strictures balloon rupture of the PUJ has yielded mixed results, with success rates of up 68–78% • Pearle et al. suggested that reason for inconsistency of results is that balloon rupture of PUJ produces ureterotomy of unpredictable length, breadth & depth • Results of their experimental study, which support this theory, show that when full-thickness ureterotomyof adequate length is produced by balloon rupture, patency rates at 6 weeks are similar to& histological changes of the healing ureter are indistinguishable from, those produced by endopyelotomy British Journal of Urology (1997), 80, 365–372.

48. Balloon dilatation: Results • Balloon dilatation seems better suited to treatment of early post-operative rather than congenital PUJ strictures, as latter appear to be mainly fibrotic & more resistant to deformation than are ureteric strictures, although exceptions have been reported • Lang & Glorioso suggest that ‘window’ for success for this indication is during 1st 3 months after surgery with a 91% success rate for strictures dilated within and a 53% success rate after that period British Journal of Urology (1997), 80, 365–372.

49. Balloon dilatation: Complications • Only reported complications following use of this technique are urinoma in 1 patient & septicaemia (despite antibiotic prophylaxis) in another British Journal of Urology (1997), 80, 365–372.

50. Endopyelotomy: Technique • 1983: Wickham &Kellettdescribed technique of full-thickness incision of obstructing PUJ with a cold knife inserted through a dilated percutaneous nephrostomy track, which they named percutaneous pyelolysisbut which is now more commonly known as endopyelotomy • After incision of PUJ, a double-pigtail stent, usually tapering from 14 F at its proximal end to 7 F at its distal end, is inserted, although Gardner et al. have challenged need for any stent, based on results of experimental study of un-intubated ureterotomy • Principle on which endopyelotomy relies is identical to that of Davis’ intubated ureterotomy, i.e. when ureter is divided longitudinally over a splint, it heals by endothelial cell proliferation on luminal aspect & smooth muscle regeneration and fibrosis on the outer aspect British Journal of Urology (1997), 80, 365–372.