urreteral stricture hẹp niệu quản

bệnh lý hẹp niệu quản là một bệnh lý khá thường gặp trong bệnh lý thận tiết niệu nói chung. có 2 nhóm nguyên nhân là mắc phải và nguyên phát. trong nguyên nhân mắc phải thì vấn đề do người thầy thuốc vẫn chiếm một tỷ lệ khá cao, điều này là do sự phát triển về các thiết bị nội soi và điều trị đường tiểu trên. vấn đề điều trị hiện nay rất phong phú và nhiều phương phát, điều này phụ thuộc vào vị trí hẹp, độ dài đoạn hẹp, mức độ hẹp, nguyên nhân hẹp cũng như trang thiết bị, trình độ của phẫu thuật viên.

Ureteral stricture

Resident Minh

A US is characterized by a narrowing of the ureteral lumen, causing upper tract

obstruction

The most common cause is UPJ obstruction, which is characterized by a

congenital or acquired narrowing at the level of the UPJ

The objective of this article is to discuss the incidence, etiology, diagnosis,

therapy, and management outcomes of ureteral strictures

Classification & Etiology

Extrinsic or intrinsic, benign or malignant, and iatrogenic or noniatrogenic.

Extrinsic malignant strictures (primary or metastatic cancer): Primary pelvic

malignancies (the cervix, prostate, bladder, and colon) → extrinsic compression of the distal ureter, Retroperitoneal lymphadenopathy (lymphoma, testicular carcinoma, breast cancer, or prostate cancer) → proximal to midureteral obstruction

Classification & Etiology (cont)

Extrinsic benign compression: idiopathic retroperitoneal fibrosis.

Intrinsic malignant strictures: TCC.

Intrinsic benign strictures: congenital (obstructing megaureter), iatrogenic, or

noniatrogenic (passage of calculi or chronic inflammatory ureteral involvement (tuberculosis, schistosomiasis))

Classification & Etiology (cont)

Iatrogenic benign strictures:

↑↑ upper tract endoscopy → ↑↑ iatrogenic ureteral stricture Factors by

endoscopy:

 Large scope size.

 Prolonged case duration.

Epidemiology (cont)

Urinary diversion: 3-5% (ureterointestinal anastomotic strictures).

Ureteral injuries (pelvic or retroperitoneal surgery, particularly abdominal

hysterectomy and sigmoid colectomy) In: Gynecologic surgery (75% of iatrogenic)

Vakili et al (a prospective analysis of 479 patients undergoing hysterectomy for

benign disease): Iatrogenic ureteral injury: 8 patients (1.7%) # the literature (0.02%-2.5%)

Ischemia → fibrosis: follows open, laparoscopic surgery or radiation therapy

Nonischemic:caused by spontaneous stone passage or a congenital abnormality

Mechanical (Less commonly): such as from a poorly placed permanent suture or surgical clip

Pathophysiology (cont)

Pathologic analysis: disordered collagen deposition, fibrosis, and varying levels of

inflammation, depending on factors such as etiology and interval since the causative insult

The resulting ureteral obstruction: mild (asymptomatic proximal ureteral dilation

and hydronephrosis), to severe (complete obstruction and subsequent loss of renal function)

Pathophysiology (cont)

Patients:

Asymptomatic.

Symptomatic only during periods of diuresis.

Severe renal colic.

The degree of symptoms correlates poorly with the degree of obstruction.

At times, severe obstruction is asymptomatic or silent.

Recovery depends on the duration of ureteral obstruction.

 A detailed patient history.

 Attention to symptoms during periods of diuresis.

 Take note of any history of prior malignancy, surgery, or radiation therapy.

 Physical examination: abdominal pain, fullness or tenderness, and costovertebral angle

tenderness.

 Ureteral strictures are often found during routine follow-up imaging after ureteroscopy or

intestinal urinary diversion.

 Less frequently, persistent urinary tract infection or pyelonephritis is associated with

unilateral ureteral obstruction.

Laboratory Studies

Urinalysis

Urine culture and sensitivities

Serum electrolytes with serum blood urea nitrogen and creatinine

Imaging Studies

Renal ultrasonography

The initial imaging study: hydronephrosis, noninvasive, no intravenous contrast

Limitations: fairly poor ureteral imaging, anatomic > functional

Imaging Studies (cont)

Computed tomography

 Noncontrast helical computed tomography (NCCT):

 Identify hydroureteronephrosis and the site of dilatation, ureteral wall thickness, calculi, urinary extravasation, Secondary signs of obstruction.

 Limitations: not a functional study, not estimate the degree of obstruction or relative renal function

 The addition of intravenous contrast:

 The degree of obstruction.

 A delayed nephrogram: anatomic relationship of the strictured ureter to the adjacent structures.

 The best test for extrinsic obstruction.

Imaging Studies (cont)

Intravenous pyelography:

o CT → IVP is rarely used.

o Particularly valuable in patients who have partial obstruction with normal renal

function

Retrograde pyelography:

o Used in preparation for endoscopic or open surgery.

o Limitations: invasiveness, cystoscopy.

Imaging Studies (cont)

Nuclear medicine diuretic scan:

Measure the degree of obstruction and to quantify relative renal function.

Measure clearance of the radiopharmaceutical over time and to calculate renal

blood flow → renal function

The most common radiopharmaceuticals: Tc 99m mercaptoacetyltriglycine.

Disadvantages: user dependence, and lack of informative anatomic data.

Imaging Studies (cont)

Intraluminal ultrasonography:

o Useful to help evaluate ureteral obstruction

o Advantages: assess ureteral submucosal and periureteral abnormalities (eg, fibrosis, vascular structures)

o Disadvantages: invasive, an inability to assess complete or near-complete obstruction

Based on location and severity:

 Location: proximal (UPJ to sacrum), mid (over sacrum), and distal (inlet

of pelvis to UVJ).

 Severity: degree of obstruction (ie, mild, moderate, severe).

 Asymptomatic

 Normal contralateralrenal function

Medical Therapy

No accepted medical treatment of ureteral strictures

currently exists

Surgical Therapy

 Recurrent stone formation

 Need to rule out malignancy

Absolute: an active and untreated urinary tract infection.

When US surgery (endoscopic or open) is contemplated, many factors should be considered:

 A terminal malignancy, extremely elderly, a high surgical risk and tolerates internal stenting

well → long-term stenting Chung et al (101 with extrinsic ureteral obstruction by stents): 41% failed within 1 year; 30% → percutaneous nephrostomy after 40 days.

 The affected kidney < 25% renal function: balloon dilation & endoureterotomy ↑↑ fail

 The renal function < 10% → nephrectomy.

 Goldfischer and Gerber (a large series): a success rate of 50%-76%

 Factors associated with a good outcome: short duration (< 3 mo) and short length of stricture

 The higher success rate with endoureterotomy.

 Most urologists recommend endoscopic incision as the initial minimally invasive management of US disease.

Balloon dilation (cont)

 For benign strictures > balloon dilation.

 Hafez and Wolf (8 published series of endoureterotomy for benign stricture disease): success

rates of 55-85% Goldfischer and Gerber: 62-100% Wolf et al: 82%

 Poor renal function (< 25%), long strictures (>1 cm), and tight stricture lumen (< 1 mm) →

poorer.

 Wolf et al: triamcinolone injection into the stricture bed + large stents (>12F) → long

strictures (>1 cm) Recent long-term studies indicate a success rate of closer to 50% after year follow-up.

5-Endoureterotomy (cont)

An antegrade or retrograde endoureterotomy may be performed, but note that a

retrograde endoureterotomy has the advantage of avoiding percutaneous renal access

Ureteral incisions can be performed with an endoscopic cold knife, or cutting

electrode or holmium:YAG laser

Keep in mind that this is a blind cut when only fluoroscopy is used

This can result in vascular complications, even in patients with normal anatomy.

Endoureterotomy (cont)

Incisions should be of full thickness into periureteral fat and for 1-2 cm proximal and

distal to the stricture At times, postincisional dilation may facilitate complete incision

The orientation of the incision should vary depending on the location of the stricture in

the ureter

Endoluminal ultrasound may assist with the identification of the periureteral vessels.

Postoperative stenting with a 7F-14F stent for 4-6 weeks is commonly performed.

Ureteral metal stents

 To treat end-stage malignant disease.

 Sometimes: apply to benign ureteral strictures and UPJ obstruction and ureterovesical

obstruction.

 Innovations in the materials and design of ureteric stents will likely continue

 Stents coated with polymers that retard stone growth These stents can be used in patients who

require long-term stent changes or in those with malignant obstruction due to terminal illness

 The stents can be changed every 6-12 months

 Periodic cystoscopy to rule out stent encrustations has been recommended.

Ureteral metal stents (cont)

Open surgical management

Open surgical management (cont)

All open procedures carry an increased risk of morbidity, increased recovery time, and increased hospitalization time compared with endoscopic approaches

Depends primarily on the location of the ureteral stricture.

Open surgical management (cont)

 Distal strictures: ureteroneocystostomy or a psoas hitch, depending on the proximity to the

ureteral orifice If more length is required, a Boari flap can bridge a 10- to 15-cm defect and may reach the mid ureter.

 Midureteral strictures: short benign strictures with minimal tension → ureteroureterostomy

TUU may be used if the donor ureter is of adequate length and the recipient ureter is not diseased Relative contraindications to TUU include conditions that may affect both ureters (TCC, urolithiasis, radiation, chronic infection, retroperitoneal fibrosis).

Open surgical management (cont)

Proximal ureteral strictures: ureteropyelostomy if length allows

Ureterocalicostomy if the renal pelvis is scarred or intrarenal in location

Long, complex upper tract ureteral strictures: traditionally → nephrectomy, bowel

interposition, and autotransplantation If not amenable to repair with urothelium, ileal

ureteral substitution may be a satisfactory solution; Contraindications: renal

insufficiency, bladder outlet obstruction, inflammatory bowel disease, and radiation enteritis

Open surgical management (cont)

Incision:

Ureteroneocystostomy and a psoas hitch can be performed through a Pfannenstiel or lower midline incision

Both a Boari flap and TUU can be performed through midline incisions

Proximal ureteral surgery can be performed through dorsal lumbotomy or flank incisions

TUU or ileal substitution: midline approach

Open surgical management (cont)

All ureteral anastomosis should be widely spatulated and free of tension

Ureteral adventitia should be carefully preserved to avoid injuring the ureteral blood

supply

Absorbable sutures are recommended to avoid a nidus for calculus formation.

Most ureteral anastomoses in adults are stented with indwelling stents to promote

drainage and to minimize urine extravasation: 10-21 days is most common for anastomotic repairs

Indication: Injury, stricture, or obstruction of the distal 3-4 cm of the ureter; distal

ureteral cancers that cannot be removed endoscopically, pelvic malignancies involving the ureter, and renal transplantation and complications arising from transplanted kidneys

Contraindication: high intravesical pressures and poor compliance (eg, neuropathic

bladder)

Via an open technique, laparoscopic, transvesicoscopic, and robotic-assisted

procedures

Ureteroneocystostomy (cont)

Various approaches to ureteral reimplantation:

 Politano-Leadbetter ureteral reimplantation.

 Modified Politano-Leadbetter procedure.

 Lich-Gregoir and modified Lich-Gregoir procedure.

 Cohen cross-trigonal reimplantation.

Politano-Leadbetter ureteral reimplantation

Cohen cross-trigonal reimplantation

Lich-Gregoir procedure

Psoas hitch

Indication: distal ureteral injury, ureteral fistulae secondary to pelvic surgery,

segmental resection of a distal ureteral tumor, and failed ureteroneocystostomy

Contraindication: a small contracted bladder with limited mobilization.

Boari flap

Indication: diseased segment of ureter is too long or ureteral mobility is too limited

to perform a primary ureteroureterostomy Boari flaps can be created to bridge a 10-

to 15-cm defect

Relative contraindication: Small bladder capacity.

Ureteroureterostomy

Transureteroureterostomy (TUU)

 Avoid kinking as the ureter crosses the sigmoid mesentery.

 Superior to the inferior mesenteric artery.

Transureteroureterostomy (TUU)

Intestine interposition

Involves relocating the ipsilateral native kidney to the pelvis.

The renal artery and vein are then anastomosed to the iliac vessels, and the healthy

ureter or renal pelvis is anastomosed to the bladder

Offers the best results in patients younger than 60 years without any underlying

aortoiliac atherosclerosis or renal disease

Autotransplantation (cont)

Laparoscopic and robot-assisted laparoscopic repair

Simmons and colleagues (2007) Open (34) Laparoscopic (12)

Average operative blood loss (ml)

The hospital stay (day) 5 days 3Overall complication rate (%) 15 8

Laparoscopic and robot-assisted laparoscopic repair

(cont)

o Fugita and colleagues reported 3 successful cases of distal ureteral stricture treated

with laparoscopic Boari flap creation

o Modi et al reported the successful use of laparoscopic ureteroneocystostomy with

psoas hitch in 6 patients with ureterovaginal fistula in whom endoscopic management initially failed

o The first reported use of laparoscopic ureteroureterostomy was published in 1998

Laparoscopic and robot-assisted laparoscopic repair

(cont)

Seidemanet Al (2009) have largest series on Laparoscopic

ureteral reimplantation:

45 patients with distal uretericstrictures

Ureteroneocystostomyin 53% (n=24) and Boariflap in 47% (n=21)

8 patients had undergone previous attempt at repair (balloon dilation, open repair, ureterolysis)

Seidemanet al

Success rate was 96% (no residual obstruction, no subsequent procedure, no renal

deterioration, no symptoms) at 24.1 months

2 patients had recurrent strictures with 1 having nephrectomyfor chronic flank pain

and pyelonephritis

Mean intraoperativeblood loss = 150cc.

Mean LOS = 3 days

3 patients had high drain outputs post-op with documented leak but were managed

conservatively

Laparoscopic and robot-assisted laparoscopic repair

(cont)

With the increasing availability of the da Vinci robot system, this technology has been

successfully applied to ureteral stricture disease It offers the advantage of easier intracorporal suturing and knot tying

Multiple centers have reported small case series documenting successful treatment of

distal ureteral stricture with robot-assisted laparoscopic reimplantation, with and without psoas hitch or Boari flap

Robotic Assisted Reimplantation

 First described in 2004 following ureteric injury during radical prostatectomy.

 UberoiJ et al 2007 described Robotic assisted laparoscopic ureteral reimplantationwith psoas

hitch.

 Patilet al 2008 performed multi-institutional evaluation of experience with Robotic assisted

reimplantation with psoas hitch:

 12 patients, 10 had distal uretericstrictures.

 Conversion rate was 0%.

 No complications w/ mean follow up of 15.5 months.