What is Subcutaneous Ureteral Bypass (SUB)?

The Subcutaneous Ureteral Bypass (SUB) system has revolutionized the treatment of upper urinary tract urolithiasis in cats over the past decade. This completely indwelling system bypasses the ureter and diverts urine from the kidney to the bladder. Let’s delve into the details:

How SUB Works:

1. Components:

   • Nephrostomy Tube: A locking-loop nephrostomy tube is placed within the renal pelvis (the part of the kidney that collects urine).
   • Cystostomy Tube: A cystostomy tube is placed within the bladder.
   • Connector: Both tubes join at a connector within the abdomen.
   • Subcutaneous Shunting Port: An accessory tube connects the connector to a subcutaneous shunting port, allowing percutaneous access to the system (see Figure 1 below).

2. Procedure:

   • The nephrostomy tube diverts urine from the kidney, bypassing any obstruction.
   • The cystostomy tube directs urine into the bladder.
   • The port allows for urine sampling and adjustments.

Indications for SUB:

• Ureteral Obstructions: SUB is used when ureteral stones, strictures, trauma, or other obstructions hinder urine flow.
• Improved Outcome: Compared to ureteral stents, SUB has shown improved outcomes and decreased complications in cats.

Why SUB Matters:

• Challenging Cases: Feline ureteroliths (stones) are often composed of calcium oxalate and can be challenging to manage.
• Renal Function Preservation: Even partial obstructions can benefit from resolution, preserving renal function.
• Obstructive Nephropathy: Untreated obstructions lead to renal damage due to increased back pressure and decreased glomerular filtration rate (GFR).

 

Understanding the disease process, treatment options, and device components is crucial for veterinary professionals. Effective client education ensures successful outcomes for cats undergoing SUB surgery. If you suspect ureteral obstruction in your feline patient, consult your veterinarian promptly. They can assess the situation and recommend appropriate treatment options, including SUB if necessary. Remember, early intervention is critical for preserving kidney function and overall well-being.