How a Subcutaneous Ureteral Bypass (SUB) device is placed in your cat

Understanding Subcutaneous Urethral Bypass Surgery in Cats

The primary reason for performing this procedure is to address an obstructed ureter, preventing the kidney from properly emptying urine into the bladder. The sub allows us to bypass this blockage, facilitating the emptying of urine from the kidney.

Anatomy: Understanding the anatomy, we visualise a cat's abdomen with two kidneys. Your cat may have one or both ureters blocked. The ureters are white tubes running through the abdomen into the bladder. When obstruction occurs, often due to stones in cats, our subcutaneous ureteral bypass system comes into play.

Implants: To explain the process, we insert a tube into the renal pelvis part of the kidney. This involves a transverse section of the kidney, where the outer brown parts generate urine filtered from the blood. The renal pelvis, typically more dilated than normal, is sealed with glue after tube insertion.

Nephrostomy Tube: The nephrostomy tube, featuring a curled J-shaped section with fenestrations, is crucial. The string at the end acts as a locking loop to secure it in the kidney, preventing unintended removal. A cuff is super glued in place on the outside of the kidney, forming a seal and limiting leakage.

Subcutaneous Ports: These ports have three main parts - the nephrostomy connection tube, cystostomy connection tube, and a central silicon diaphragm. The diaphragm allows the use of a special needle (Huber needle) for flushing and draining the system, preventing mineral collection and tube obstruction.

Second Tube: A second tube, similar to the one in the kidney, is sutured to the outside of the body wall, completing the circuit. This subcutaneous port system, rather than direct connection, offers benefits such as easy urine sample collection and system flushing.

Benefits: Regular flushing helps control mineral stone formation, a common issue in these cats. The placement involves visualising the open abdomen, inserting the catheters into the kidney and bladder, and using fluoroscopy for confirmation. Contrast injection ensures proper tube positioning and patency.

Placement: The fluoroscopy also helps identify the size and diameter of the ureter, assisting in locating any obstructions. Once in place, the contrast injection into the subcutaneous port confirms the patency of all tubing.

In summary, this video provides insights into the placement and use of subcutaneous urethral bypass in cats. For any questions, feel free to contact us at Cat Specialist Services.