Medically reviewed by Dr. Scott Rizzo, DVM, MS, DACVIM, MBA, and Dr. Grace Clark, DVM, DACVIM
Some dogs with urethral sphincter mechanism incompetence (USMI) keep leaking even on medication. Others can’t take the medication at all. For many of these dogs, collagen injections are the next step. This post is part of our guide to USMI in dogs, which explains what USMI is and why it happens.
What collagen injections do
USMI means the sphincter muscle that holds urine in the bladder is too weak to stay closed when your dog relaxes or sleeps. A collagen injection adds bulk to the lining of the urethra near the bladder. With that extra cushion, the urethra closes more snugly and holds urine better. The material is a crosslinked collagen made for this use, and it’s placed just under the lining of the urethra.
Which dogs are good candidates
Collagen is usually considered for dogs that still leak on medication such as Proin or Incurin, or that can’t take those drugs. Before we recommend it, we want a clean urine culture so we know there’s no infection. We also want a cystoscopy, a look inside the urethra and bladder with a small camera. That exam checks for problems like an ectopic ureter, which is common alongside USMI. Collagen is often a good choice for older dogs because it avoids open surgery.
How the procedure works
Your dog is under general anesthesia. We pass a cystoscope into the urethra and inject small deposits of collagen into its wall while we watch on the monitor. There is no incision. Because we’re already looking through the cystoscope, we can examine the urethra and bladder during the same anesthesia.
Dr. Scott Rizzo and Dr. Grace Clark perform collagen injections, and only at our Louisville hospital. We’ll talk with you about how to prepare and what to watch for at home before your dog’s procedure.
What to expect afterward
Many dogs are noticeably drier after collagen injections, and some become fully continent. Others still need medication to stay dry, and collagen often works well alongside it. In one published study of 40 female dogs, 27 were continent after their collagen injections, for anywhere from one month to more than five years. Ten more improved, and six of those became fully continent once medication was added. Those are results from published research, not a promise for any one dog.
The effect can fade over time. In that same study, some dogs had more leaking again within the first year before things leveled off. If leaking comes back, we’ll talk through the next options with you. Those might include another injection, a change in medication or a hydraulic urethral occluder.
Possible side effects
Side effects in that study were mild and short lived. As with any procedure, anesthesia carries some risk, and we’ll go over it with you. Rarely, too much bulk can make it harder for a dog to urinate.
If your dog is straining and can’t pass urine, that is an emergency. Call or come in right away. VSP Louisville’s emergency and urgent care is open every day until 10 PM. Walk in, no appointment needed. (502) 901-7990.
Collagen or an occluder?
Collagen avoids surgery and can be repeated, but it may not last as long. A hydraulic urethral occluder is an adjustable artificial sphincter placed during surgery by board certified surgeon Dr. Joshua Bruce of Kentucky Veterinary Surgery. It’s usually saved for dogs that still leak after medication and collagen. We’ll help you weigh the options based on your dog’s age, health and how much leaking is going on.
Questions we hear often
Does my dog need an incision for collagen injections?
No. The collagen goes in through a cystoscope, which passes through the urethra, so there is no incision.
How long do collagen injections last?
It varies. Some dogs stay dry for years, and others notice the leaking creeping back within a year. If that happens, we can talk about another injection or other options.
Can my dog still take Proin or Incurin after collagen?
Yes. Some dogs need medication along with collagen to stay fully dry.
Where can my dog get collagen injections?
At VSP, Dr. Scott Rizzo and Dr. Grace Clark perform them only at our Louisville hospital.
Do I need a referral?
No, you don’t need a referral. We still want your family vet included in your dog’s care, so we’ll request their records and keep them up to date before and after the procedure.
Talk with us
If your dog is still leaking on medication, collagen injections may help. Call (502) 901-7990 or request an appointment. Referrals from your family vet are always welcome.
To learn more, go back to our guide to USMI in dogs, or read about hydraulic urethral occluders and our interventional radiology services.
