Obstructive Traumatic Ureteral Disease Flashcards
Most common urolith type in dog? (2)
struvite (magnesium ammonium phosphate) and calcium oxalate
Most common urolith type in cats? (1)
Calcium oxalate
Where are calculi more likely to be found in what ureteral region?
Proximal ureteral region
Types of ureteral mass/neoplasia, that are benign? (3)
Fibropapilloma
Fibroepithelial polyp
Leiomyoma
Types of ureteral mass/neoplasia, that are malignant?(4)
Myosarcoma
TCC
MCT
STS
Where are benign mass more likely to be found in ureter?
Proximal
Where are malignant mass more likely to be found in ureter?
Distal
Clinical signs of ureteral obstruction? (3)
- Absent (e.g. with unilateral obstruction where contralateral renal function is normal, or not severe enough to cause uraemia)
- Typical of a UTI (stranguria, pollakiuria, haematuria)
- Typical of chronic kidney disease/acute kidney Injury (lethargy, anorexia, vomiting, PU/PD).
What imaging modality is best for ureter urolith?
Xrays - most are radio-opaque
U/S - all types seen on ultrasound
How can uroliths be medically managed?
Medical management options include the administration of medications to relax ureteral smooth muscle, such as prazosin, tamsulosin, amlodipine, amitryptyline and glucagon
Lithotripsy
What are the surgical options for uroliths? (6)
- Nephrotomy
- Pyelolithotomy
- Ureterotomy
- Double-pigtail ureteral stent placement
- The more recently reported subcutaneous ureteral bypass
= Ureteral resection with re-implantation (Ureteroneocystostomy)
What is caused if the ureter can also leak in the retroperitoneal space creating a distension of that space?
Urinoma
How can the integrity of the ureter be assessed?
intravenous urography or antegrade pyelography (injection of contrast directly in the pyelic cavity) when in doubt.
In a direct antegrade pyelogram, where is the injection performed?
Level of renal pelvis
What is seen with a direct antegrade pyelogram if there is a loss of ureter integrity?
Contrast material is seen flowing distally but marked pyelectasia is present.
If there is ureteral trauma, what are the treatment options if there is a proximal lesion/obstruction of a single site? (1)
Ureterotomy
If there is ureteral trauma, what are the treatment options if there is a proximal lesion/obstruction of multiple sites? (2)
- SUB
- Double pigtail ureteral stent
If there is ureteral trauma, what is the treatment option if there is a proximal lesion/obstruction beyond repair?
Ureteronephrectomy
If there is ureteral trauma, what are the treatment options if there is a mid lesion/obstruction of a single site? (1)
Ureterotomy
If there is ureteral trauma, what are the treatment options if there is a mid lesion/obstruction of a multiple sites? (2)
SUB
Double pigtail ureteral stent
If there is ureteral trauma, what are the treatment options if there is a mid lesion/obstruction?
- Ureteral end to end anastomosis (spatulated) +/- ureteral stent
- Ureteroneocystotomy
If there is ureteral trauma, what are the treatment options if there is a mid lesion/obstruction?
Ureteroneocystotomy +/- cystopexy
If there is ureteral trauma, what are the treatment options if there is a distal lesion/obstruction of a single site?
Ureterotomy
If there is ureteral trauma, what are the treatment options if there is a distal lesion/obstruction of multiple sites? (2)
- SUB
- Double pigtail ureteral stent
If there is ureteral trauma, what are the treatment options if there is a distal lesion/obstruction of multiple sites beyond repair?
Ureteronephrectomy
How long for ureter to re-epithelization?
4-10 days
How long for ureter mural layers to regenerate?
4-6 weeks
Renal descensus and cystopexy (psoas hitch): what does this mean?
A renal descensus is a procedure by which the kidney is dissected from its sub lumbar attachments and is only attached by its vessels and ureter. It is moved caudally to minimise the gap between the ureter and bladder, therefore minimizing tension. It is often associated with a cystopexy where the bladder is attached dorsally to the psoas muscle
Where is the bladder normally attached in a STANDARD cystopexy? (Not renal descensus)
transversus abdominis muscle
What is required for ureter surgery for visual reasons?
surgical loupe, or in small dog/cat surgical microscope
High intensity light
What should be in the surgical kit for ureter surgery?(6)
microsurgery needle holder
Microsurgery forceps
fine dissecting scissors,
Beaver blade handle,
Mixter (right angle) forceps
Cotton buds (for haemostasis)
Why are non ratcheted instruments advised in microscopic surgery?
To avoid jittering movement
What is the diameter of a non dilated ureter in cats?
0.4mm
What is a dilated ureter lumen size in cats?
1-2mm
Where is the ureter dilated compared to the obstruction?
Proximal to
What can be placed under the ureter in surgery to enhance contrast?
Coloured sheet
How should the ureter be manipulated?
By the peri-ureteral fat
Is a ureter incision made longitudinally or transverse?
Either
What needs to be performed if it found a calculus is embedded in the ureter wall?
ureteroureterostomy (end to end anastomosis of the ureter)
Before closing the ureter - what MUST be performed?
Ureter flush
What suture/pattern to close ureter in large dogs?
7/0 monofilament absorbable or non-absorbable suture in a simple continuous or simple interrupted manner.
What suture/pattern to close ureter in cats?
9/0 monofilament absorbable or non-absorbable suture in a simple continuous or simple interrupted manner.
What can be placed in ureter to avoid stenosis and leakage?
Double pigtail ureteral stent
Ureteral stent Placement can be achieved percutaneously, via endoscopy or ventral midline coeliotomy, though in cats only one of these techniques is recommended. Do you know which?
Ventral midline coeliotomy
Which direction can a ureteral stent be placed?
The stents are placed either retrograde, from the uretero-vesicular junction, or normograde via an approach to the renal pelvis using fluoroscopic guidance.
How is a ureteral stent placed?
A guidewire is first inserted, and then a ureteral dilator is passed over the top followed by the double-pigtail indwelling catheter. One end is situated within the renal pelvis and the other in the bladder lumen.
Do we remove the ureterolith prior to stent placement?
not usually removed unless it prevents passage of the guidewire, in which case a ureterotomy may be performed.
Following ureteral stent placement - how many cats can get a late complication?
30%
Post op ureter stent placement complications (7)
- dysuria
- haematuria
- stranguria
- UTI
-Stent migrate - fracture
- Obstruct
What is the SUB technique?
involves placement of an internal locking-loop nephrostomy tube and an internal cystostomy tube (locking loop as well nowadays) connected via a specialised port sutured subcutaneously on the outside surface of the body wall to completely bypass the ureter (i.e. complete external to the ureter).
Placing a SUB
- How should the nephrostomy catheter be placed?
Fluoroscopic guidance using a modified Seldinger technique
SUB technique:
How is the cystotomy tube placed?
Through a Purse-string suture in the bladder wall, and the catheter cuff and overlying silicone ring are secured to the bladder serosa using sutures and sterile tissue glue.
Following placement of cystotomy and neprostomy tube - what is the next step in placing a SUB?
A subcutaneous pocket is created on the abdominal wall for the port, and the free ends of the two tubes are then tunnelled through the body wall and are connected. The port is sutured to the body wall with nonabsorbable monofilament suture.
Step by step SUB placement..
1 Isolation of the caudal pole of the kidney
2 Insertion of a 18G catheter inside the renal pelvis via the caudal pole
3 A wire is inserted through the catheter and placed inside the renal pelvis (angled towards the ureter in case the renal pelvis is only mildly dilated)
4 The insertion of the wire is guided by a pyelogram done at the time of catheter placement
5 The nephrostomy tube is inserted over the flexible guidewire. The nephrostomy tube is maintained rigid by the insertion of a hollow stiff trocar
6 The nephrostomy tube curled inside the pelvis by slowly advancing the tube as the trocar and wire are withdrawn
7 The Dacron cuff of the nephrostomy tube is glued in place
8 The cystostomy tube (B) is placed in a middle of a purse string (A) at the apex of the bladder
9 The tubes are connected to the port
10 The exit points of the tube on the body wall should be located about two fingers widths of the proposed location of the port to avoid any kink in the tubes
11 The port is secured to the body wall using a series of simple interrupted sutures
12 Extra-sutures can be placed between the blue boot and the body wall to further secure the device
When is it suggested to flush a SUB (based on manufacturer?
(using the subcutaneous port and a non-core needle) prior to discharge, at 1-week post-operatively, then at 1-month, and every 3-months thereafter.
What should a SUB be flushed wit?
Tetrasodium ethylenediaminetetraacetic acid (tetra-EDTA), trade name T-FloLoc.
What chemical restraint allows SUB flushing?
Normal restraint; or light sedation
Intraoperative complications of SUB (3)
- Inability to access the renal pelvis
- Damage to tube whilst placing sutures
- Urine leakage around nephrostomy tube if improperly placed
Late complications of SUB placement (7)
- Device kinking
- UTI
- Purulent material
- Urloith material blocking
- Blood clot
- Device leaking
- Non infectious cystisis
