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How a Subcutaneous Ureteral Bypass (SUB) Device is Placed
If your cat is suffering from a ureteral obstruction, a Subcutaneous Ureteral Bypass (SUB) device may be the solution to restore their health.
Ureteral obstructions, often caused by urinary stones, can prevent the kidneys from draining urine properly into the bladder.
Left untreated, this condition can lead to severe complications, including kidney failure.
An SUB device allows urine to bypass the blockage and flow freely from the kidney to the bladder.
But how exactly is this device placed, and what does the procedure involve?
Understanding your cat's anatomy
To better grasp how an SUB device works, it’s helpful to understand a bit about your cat’s anatomy. Your cat has two kidneys, each responsible for filtering waste from the blood and producing urine. The urine travels from the kidneys to the bladder through thin tubes called ureters. When a blockage occurs, usually due to urinary stones, the ureter becomes obstructed, preventing urine from flowing normally. This can cause the kidney to swell and stop functioning properly.
In some cases, one or both ureters may be blocked, which is where the SUB device comes in. The SUB system acts as a bypass, allowing urine to flow around the obstruction so it can drain from the kidneys into the bladder.
How the SUB device is placed
The placement of an SUB device is a delicate, intricate procedure performed by a veterinary surgeon.
Here’s how it works:
Implants in the kidney: First, a small tube is inserted into the renal pelvis, the part of the kidney that collects urine. This tube allows urine to drain from the kidney, bypassing the blocked ureter. The renal pelvis is often swollen due to the obstruction, and this swelling helps the surgeon insert the tube securely. After placing the tube, the opening is sealed using a special glue to prevent any leakage.
Nephrostomy tube: The tube used in the kidney is called a nephrostomy tube, which has a curled, J-shaped tip designed to stay securely in place. The tube features small openings, or fenestrations, that allow urine to flow through it. A small string at the end of the tube forms a locking loop, securing the tube in the kidney and preventing it from slipping out. A cuff is also glued in place on the outside of the kidney to create a tight seal, limiting the risk of leaks.
Subcutaneous ports: Once the nephrostomy tube is in place, the next step involves connecting it to a subcutaneous port system. This port sits just under your cat’s skin, and it has several important functions. It connects the nephrostomy tube from the kidney to the cystostomy tube, which drains urine into the bladder. The port also has a silicone diaphragm, which allows vets to easily flush and drain the system using a special Huber needle. This is crucial for preventing blockages caused by mineral buildup in the tubes.
Second tube to the bladder: A second tube, similar to the one in the kidney, is inserted into the bladder. This tube ensures that urine can flow from the kidney through the SUB device and into the bladder, where it can be safely excreted.
Benefits of the SUB device
The SUB system offers many benefits for cats with ureteral obstructions:
Prevention of mineral buildup: One of the main advantages of the SUB device is that it can be regularly flushed to prevent the formation of mineral stones, which are common in cats with urinary issues. By keeping the system clear, the risk of future blockages is significantly reduced.
Ease of urine collection and monitoring: The subcutaneous port system also allows vets to easily collect urine samples for analysis. This is especially important for monitoring your cat’s kidney function and detecting any signs of infection or stone formation.
Confirming the placement: fluoroscopy and contrast injection
To ensure that the SUB device is positioned correctly, the vet uses fluoroscopy, a type of real-time X-ray, during the procedure. Fluoroscopy helps the surgeon visualise the kidneys, ureters, and bladder in detail, allowing them to accurately place the tubes and identify the location of any blockages.
Once the SUB device is in place, the surgeon injects a contrast dye into the system through the subcutaneous port. This dye helps confirm that the tubes are properly positioned and that urine is flowing as it should. If the dye moves smoothly through the system, it indicates that the bypass is working and the ureters are effectively bypassed.
The placement of a Subcutaneous Ureteral Bypass device is a highly effective solution for treating ureteral obstructions in cats. This procedure can significantly improve your cat’s quality of life by restoring normal urine flow and preventing dangerous complications. While it may sound complex, the SUB device offers a safe and reliable way to manage a common and serious condition in cats. If your cat has been diagnosed with a ureteral obstruction, talk to your vet about whether an SUB device could be the right option for them.
“Fluoroscopy helps ensure the device is positioned correctly.”
Are you worried about your cat’s health?
If you are concerned about your cat, please reach out to our friendly team. Call us on 1300 228 377 or fill out the contact form below. In an emergency, please contact your local vet.
For vets – to refer a patient or book a telehealth consultation, please call us on 1300 228 377, book through the portal or fill in the form.
Meet The Author
Dr Rachel Korman
Specialist in Feline Internal Medicine
BVSc MANZCVS (Internal Medicine) FANZCVS (Feline Medicine)
Dr. Korman’s childhood love for cats led her to veterinary medicine, and early on, it was clear that feline care was her calling. After graduating from the University of Queensland in 2000, she worked in small animal and feline-only practices across Australia and the UK.
She received a Senior Clinical Training Scholarship from the Feline Advisory Bureau (now International Cat Care) at the University of Bristol, where she researched feline infectious and haematological diseases, and in 2018, became a Fellow of the Feline Medicine Chapter of the Australian New Zealand College of Veterinary Scientists and a registered Feline Medicine specialist.
Frequently Asked Questions
What is a SUB device for cats?
A Subcutaneous Ureteral Bypass (SUB) device is implanted to help urine bypass a blocked ureter. It redirects urine flow from the kidney to the bladder.
How is the SUB device placed?
During surgery, tubes are placed in the kidney and bladder and connected through a port beneath the skin. Fluoroscopy imaging helps guide correct placement.
Why is fluoroscopy used during the procedure?
Fluoroscopy provides real-time X-ray imaging. It allows the surgeon to visualise the kidneys, ureters and bladder during placement.
How is the SUB device monitored after surgery?
The port allows veterinarians to flush the system periodically. This helps prevent mineral buildup and monitor kidney function.
Can the SUB device improve a cat’s quality of life?
Yes. By restoring urine flow, the device can help prevent complications associated with ureteral obstruction.
Patient Stories
Our commitment to feline health is best seen in the stories of the cats we’ve had the privilege of treating. These journeys highlight the dedication, expertise and compassion that drive us.
Each patient faced unique challenges, and it was our honour to offer high-quality care and help them regain strength and happiness. We value the deep bonds with cats and their owners, knowing the difference we make in their lives.
Kitty, a lymphoma survivor
We first met Kitty after she was referred to CSS for the evaluation of a large intestinal mass
Poppi finds her feet again
Following surgery to remove a hairball obstruction, Poppi was referred to us at CSS as she had not bounced back as expected
Rusty and his ongoing chronic rhinitis journey
Lifelong nasal issues, including persistent discharge and breathing noise, have been a bit of a thorn in Rusty’s side.
Lando’s long game with cryptococcus
Lando was referred to CSS because he had a swelling under his jaw that wouldn’t go away.
Popeye coughs up the culprit
Ares is a handsome young Maine Coon who was referred to CSS after presenting at AES with sudden lameness in his back leg.
Key Takeaways
A SUB device is used to restore urine flow when the ureter is blocked.
The system includes tubes connecting the kidney to the bladder via a port under the skin.
Fluoroscopy and contrast dye are used during surgery to confirm correct placement.
Cat Specialist Services Reviews 
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Tanya Bell
6 months ago
We transported our cat here from another animal hospital, as his condition was too complex for them. Our pet was given the highest quality of care, multiple investigations/procedures being able to be done at the one place a godsend. We were kept up to date frequently throughout his stay. All questions & options explained thoroughly. Being able to have private visits certainly helped us and our cat too. I would highly recommend Cat Specialist Services at Underwood. Amazing staff from reception, vet nurses, vets & specialists. Oh, and yes he is recovering wonderfully at home.
Melinda Cox
A month ago
So very happy we were asked to come here for advice for our NORBIT. He has had 2 x UTI blockages within weeks of each other since turning 6. Surgery seemed to be his only option and he didn’t feel it was very fair on him if we didn’t at least exhaust all other avenues first.
Dr Allison was very thorough in her tests and has let us know she would like to treat the cause of the problem. Great news.
It may lead to removal of crystals in his bladder if his diet doesn’t let him pass them naturally.
At least this surgery won’t be as severe at taking his penis off him – so as his fur parents – we are very happy with this.
We await further tests to see what’s in store for him.
NORBIT will now be a patient of the clinic as we are so far very happy with his treatment thus far.
Lesley Rosekrans
A month ago
Hi has only been a week since losing my beautiful Peaches but can’t thank Dr Cindy, Maree and Jackie enough for the tender care they gave her and they after care they gave me. I sincerely thank them and can’t recommend the Clinic highly enough they are such caring people. Peaches I’m happier times.
Madison McEwan
A month ago
I cannot thank the entire CSS team enough and especially Dr Cindy for the care they provided for our boy with a urinary blockage, and we will be taking both our cats here from now on. The clinic is exceptionally clean and calming compared to all other clinics we’ve been too, and all staff from the reception to the nurses/vets were so supportive during a stressful time. I knew from the first minute that I got to see him after he was transferred that he was in the best place, and that the staff genuinely care about their well-being and positive long term outcomes. We were given regular updates and full transparency, so much information including QR video codes on how to administer medications, along with print outs and emails about how to best help avoid future issues or recurrence. Our boy got to smooch on everyone and was beyond well looked after. Thank you again, you all made an incredibly stressful situation actually manageable and calming.
Astrid El Gamal
6 months ago
Dr Wan-Ju has been treating my baby since her first seizure in November 2025 and she has been fantastic.
Everybody at the clinic is so friendly and caring and I know my baby is in good hands.
Thank you team!
Deeba M
3 months ago
Dr Alison Jukes from CSS Underwood is an AMAZING feline physician. She is kind, professional, thorough and our cat is blessed to have her on his side. She even was able to save us money and invasiveness by being skilled to the level of doing ultrasound on two separate occasions without our cat needing to go under full sedation. Our other cat was recently seen by Dr Jukes as well, and she made sure our cat’s heart was ok. I also want to thank the lovely Jacqueline and Mairead from customer care. They are very kind each time I see them and call up. Sending thanks from our family, including Smokey and Floozy!
Judith Dionysius
A month ago
My whole experience with CSS was positive – from the first email I received giving lots of information regarding the process of radioactive iodine treatment to the expected costs, to checking my cat in for the treatment, boarding for 2 weeks after the treatment and picking her up to come home. They didn’t push for any tests that were not necessary.
Janelle Wieden
5 months ago
We never knew this service existed but we are very grateful we were referred to them. Our vet Cindy was really great, she made us feel at ease during a very stressful time. We got the sense straight away the Leo was in good hands. This service made us feel better knowing that they specialise is cats only. Would highly recommend their services
Georgia Carter
5 months ago
My Lani finished her I-131 treatment today and I am beyond impressed with the way she was looked after. I am by definition a neurotic pet owner and sending my fur child away for a week was seriously daunting.
I was given daily updates about how kitty was eating, toileting and behaving. This really put my mind at ease. Vets and vet nurses were so accomodating and allowed Lani to have her favourite foods from home prepared her favourite way.
Her vet was so thorough when explaining her treatment and condition to me.
The ladies at reception were so friendly and understanding.
I honestly cannot recommend this clinic enough and I am so thankful for the positive experience Lani and I have had.
Lauren Woodward
A year ago
My sweet ginger boy Louis was hospitalised at CSS for a Urinary Obstruction. Dr Cindy and all the reception staff were amazing and empathetic. I would often ring up with questions post procedure and Dr Cindy would make time to talk and explain things to me
Service Locations
Cat Specialists accepts referrals for cats across Brisbane and surrounding regions, working closely with local veterinary clinics to provide specialist diagnosis, treatment, and ongoing management.
Contacting Us
Pet Owners
If you would like to talk about treatment for your cat, call us on 1300 228 377 or fill in the form.
In an emergency, please contact your local vet.
Vets and Nurses
To refer a patient or book a telehealth consultation please call us on 1300 228 377, book through the portal or fill in the form. For advice calls, please see the guidelines here.
Monday-Friday: 8 am-6 pmSaturday/Sunday - Closed