Managing Urethral Obstructions in the Dog
What is a Urethral Obstruction?
Bladder stones becoming lodged in the urethra are the most common cause of obstruction. This occurs mostly in the male dog because they have a long urethra which narrows distally.
What is a Urethrotomy?
A urethrotomy is a surgical procedure that entails entering the urethra at the level of the obstruction to remove it. It is more difficult to remove stones through a urethrotomy than a cystotomy. The complication rate tends to also be higher with the urethrotomy. This is why it is better to retropulse the stones back into the bladder and remove them from there.
Situational Awareness
Retropulsing stones from the urethra is another LIFE SAVING procedure every veterinarian will need to perform someday.
If the obstruction is ACUTE, the dog will quickly become uncomfortable, anxious, and unable to pass urine despite frequent attempts. This is an emergency situation; the onset of azotemia is an indicator of severity. In acute cases retropulsion should be successful 100% of the time. Lack of success is usually due to inappropriate catheter selection and flushing technique. Follow the steps described here and ensure that your team (yes, you need a team for this) understands their role.
A CHRONIC obstruction usually results from a smaller stone being lodged in the urethra, typically at the level of or within the os penis. The stone is too large to be passed during micturition but is not so large that it fully obstructs the flow of urine. These patients present with a history of taking a long time to urinate, often with a very narrow stream. They may also display pollakiuria, dysuria and hematuria. These are by far the more difficult stones to dislodge and retropulse back into the bladder. Failure to successfully retropulse a stone from the urethra is more likely to occur with this patient.
Get ready to retropulse:
All the information you need.
Step by step explanations of the procedure.
This content is designed for veterinary professionals. If you are a pet owner, please consult your vet if you have any questions about a surgery.
Pre-procedural Considerations:
Pre-procedural Considerations:
- Stabilize the patient
- palpate to assess the bladder size
- get blood work to assess the kidneys and electrolytes
- establish an IV access
- Empty the bladder
- use a small gauge catheter to get past the stone and into the bladder.
- If not possible – how full/turgid is the bladder?
- if not turgid: proceed cautiously with retropulsion
- If turgid: perform a cystocentesis first
- Good radiographs of the Lower Urinary Tract
What the client needs to know:
- Retropulsions are usually successful with acute obstructions when properly performed.
- Once the stone is dislodged from the urethra, the patient can be taken to surgery so the stones can be removed from the bladder, or, if necessary, the patient can be stabilized with fluids for several hours and have the surgery the next morning or later that day, once stable.
- Retropulsion of chronic uroliths, although often successful, are more likely to require a urethrotomy than the acute ones. A cystotomy may still be necessary after a urethrotomy, depending on the number and size of stones that are in the bladder.
- Appropriate dietary management will be necessary
Key points for a successful retropulsion (and watch the video!):
- Figure 1
Place a large red rubber or stiffer PVC catheter up against the urolith. Occlude the penile orifice around the catheter
- Figure 2
Quickly push a BOLUS of warm saline through the catheter. Often this is sufficient to dislodge the stones. If the stones have moved but have not completely cleared the urethra (as per radiographs), simply repeat these 2 steps. Check the size of the bladder frequently through out the procedure.
- Figure 3
If steps 1&2 did not succeed in dislodging the stones then have an assistant occlude the pelvic urethra with a finger.
- Figure 4
Then repeat steps 1&2; the bolus of warm saline against the occluded pelvic urethra will serve to expand the penile urethra.
- Figure 5
As the warm saline is bolused into the urethra, the assistant will lift their finger off the floor of the pelvis, allowing the saline (and uroliths) to flow into the bladder. The occlusion/ unocclusion of the pelvic urethra is done intermittently while the saline is being bolused. Check the size of the bladder frequently through out the procedure.
Get ready to retropulse:
Instrumentation:
- Assemble your team
- Sedation and pain medications (valium or medetomidine and narcotic)
- Assemble your equipment:
- Large PVC or red rubber catheter
- Large syringe (35 or 60cc) to connect to catheter
- Saline for flushing (preferably warm)
- Sterile lubricant
- Set up in radiology
Post-obstruction actions:
- Proceed with a cystotomy now or at a more convenient time or once the patient is better stabilized for a general anesthesia.
- Leave a soft catheter (red rubber or other but not the PVC) within the urethra until the cystotomy can be performed.
What you get when you register:
- Detailed description of each step and why they will work if applied properly, and fail if not.
- Further drug considerations
- How to manage the more difficult/tenacious obstructions (i.e. plans B, C and D).
- How to perform a urethrotomy safely, minimizing complications; what to expect post-op.
