A functionally significant impairment of urinary transport from renal pelvis to ureter.
Epidemiology
Incidence difficult to know due to large asymptomatic population.
May present any time from antenatal to elderly – adults most often symptomatic in teens/20s.
Males > females.
Left > right.
Can be bilateral. Associated with horseshoe kidneys, VACTERL syndrome, other congenital abnormalities.
Causes
Aperistaltic segment:
- Abnormal muscle fibres (spiral fibres replaced with longitudinal fibres or fibrosis) and less cells of Cajal histologically (ureter canalises up and down – failure of terminal canalisation?)
Crossing vessel:
- Controversial – found in 30 – 40 % of children and adults undergoing pyeloplasty – but may also be present in 20 % of non affected population
Clinical features
Classically Dietl’s crisis – pain after fluid intake mimicking renal colic with nausea and vomiting, settles conservatively.
Atypical presentations – UTIs, haematuria, stones, worsening renal function, workup for hypertension.
Often found incidentally on imaging.
Work-up
Urine testing – microscopy and culture
Bloods
- Renal function, previous renal functions
Imaging:
Ultrasound
- Will often show hydronephrosis and without proximal ureteric dilation
CT
- Non contrast often ordered – dilated renal pelvis without ureteric dilation.
- Contrast – compare drainage in delayed phase, compare contrast uptake/parenchyma, assess vasculature
Retrograde pyelogram – can often be done in same sitting as intended pyeloplasty – assess insertion point of ureter to dilated pelvis
Whitaker test – antegrade infusion of contrast with measures of intrarenal pressure and bladder pressure – intrapelvic pressures > 22 cm H2O indicates obstruction
MAG3 is test of choice – provides information on split function, and objective information of drainage and obstruction.
Poorly functioning kidneys or massive distended redundant renal pelvises may interfere with assessment of drainage.
Management
Goals of intervention:
- Relieve symptoms
- Protect or improve renal function
- Restore normal urinary drainage
Indications for intervention (adults):
- Symptomatic – pain, infections, stones
- Imaging – concordant with PUJ obstruction
- Obstruction on renogram
In kids – symptoms, recurrent UTIs, worsening creatinine, split function deterioration 5 – 10 %, split function < 40 %, increasing AP diameter on ultrasound
Management options
- Conservative / observation
- Endoscopic
- Pyeloplasty
- Palliation / long term stent
- Nephrectomy
Conservative
- Annual creatinine, ultrasound +/- MAG3 and symptom review
- Asymptomatic with preserved split function
Palliation / long term stent
- If symptomatically obstructed (including UTIs) but unfit for pyeloplasty
Endoscopic – endopyelotomy
- 60 – 75 % primary success rate
- Full thickness lateral incision at proximal ureter / PUJ theoretically out to fat
- Often done with laser
- Pros – less invasive, quicker recovery, good for failed pyeloplasty, transplants
- Cons – less successful, may compromise pyeloplasty
Technique for endopyelotomy:
- Cystoscopy / RPG
- Flexible ureteroscopy alongside safety wire
- Laser on tissue settings (0.8 J, 10 Hz) – lateral incision to avoid vessels – gradually deepening the incision (posterolateral to avoid crossing vessel)
- Large stent – endopyelotomy stents with 12 fr proximal end or if not able to pass, 8 fr
- IDC
Often useful procedure after a failed pyeloplasty. If concomitant renal stones, can use antegrade approach.
Pyeloplasty
- Success rates reported 90 %
- Open vs laparoscopic / robotic
Dismembered pyeloplasty is the usual approach – can be adapted for wide variety of situations
Principles:
- Creation of dependent and funnelled reconstruction
- Watertight anastomosis with absorbable sutures
- Tension free
- Widely patent
- Stented and drained
- Preservation of vascular supply
Steps (lap):
- Cystoscopy + RPG first if not done prior in lithotomy (exclude distal obstruction)
- Lateral position a la nephrectomy. Ports same.
- Medialise colon and expose renal pelvis/ureter
- If point of obstruction not clear, can fill renal pelvis via needle
- Transect ureter below point of obstruction (healthy ureter)
- Excise redundant pelvis avoiding calyces
- Spatulate ureter on its lateral surface (away from vasculature)
- Avoid rotation of ureter
- Apical sutures (apex of spatulation to most dependent renal pelvis) then close front and back wall – 4-0 monocryl or v-lock
- Dependent funnelled anastomosis which is watertight and tension free with absorbable sutures over a stent
- Transposed anterior to a crossing vessel
- Cover with fat if able
- Drain and catheter
Open:
- Cystoscopy / RPG if not done prior to confirm no distal obstruction
- Flank incision in lateral position – tip of 12th forward
- Exposure of kidney, medialisation of peritoneum and open Gerota’s posteriorly away from peritoneum
- Expose PUJ / clear it of fat.
- Expose ureter with only a little skeletonised and the rest of adventitia preserved
- Transect ureter below obstruction and crossing vessel if present (after placing stay suture)
- Excise diamond-shaped segment of redundant pelvis ensuring ureter will reach
- Keep away from calyces which may be close
- Tenotomy scissors
- Spatulate lateral ureter
- Apical suture from inferior dependent renal pelvis to apex of lateral spatulation
- Dependent funnelled anastomosis which is watertight and tension free with absorbable sutures over a stent
- Transposed anterior to a crossing vessel
- Cover with fat if able
- Drain and catheter
Other options if can’t do dismembered:
- Foley V-Y plasty – most useful for very high insertions
- Culp De-Weerd spiral flap – for long lengths of abnormal ureter/PUJ
- Scardino Prince vertical flap – for long lengths with high insertion
- Mobilise the kidney down inferiorly – pex to QL with bolstered sutures
- Ureterocalycostomy (if no extrarenal pelvis at all)
Follow up:
- IDC out prior to drain on the ward.
- Stent out at 6 weeks.
- USS and Cr at 3 months and symptom review.
- If concerns – MAG3 at 6 months, otherwise 12 months with bloods.
- Annual imaging and bloods for 3 years.
Nephrectomy
- Indicated for poorly or non-functioning kidneys – below 10 – 15 % (depending on patients age, renal function, preference).
- Consider repeating MAG3 with a stent in to relieve obstruction if initial result equivocal.