Ureteral Reimplantation (Anti-Reflux Surgery): Cohen, Lich-Gregoir

The ureter (the urine channel between the kidney and the bladder) does not enter the bladder at a right angle; it passes through an oblique tunnel within the bladder muscle before opening onto the inner surface. As the bladder fills and contracts, this tunnel is compressed from outside and works like a one-way valve. In vesicoureteral reflux, this tunnel is short, or the opening has shifted sideways; the valve fails to close and urine flows back up to the kidney.

In the Cohen technique, the bladder is opened, the ureter is freed from its own opening, and it is passed through a horizontal tunnel across the bladder base (trigone) toward the opposite side, then stitched to its new opening. In bilateral reflux, the two ureters cross each other. Because the tunnel is horizontal, the risk of kinking and obstruction is low; this is the most widely used technique and the one with the most predictable results.

In the Lich-Gregoir technique, the bladder is not opened. At the point where the ureter enters the bladder, the bladder muscle is split lengthwise from the outside, the ureter is laid into this groove, and the muscle is closed back over it to create a new tunnel. Because the inner lining of the bladder is not disturbed, blood in the urine and bladder spasms are less common, catheter time is shorter, and the hospital stay is usually shorter too.

Open ureteral reimplantation is one of the most predictable operations in pediatric urology: resolution of reflux is reported in the literature at roughly 95–98%. This figure depends less on the specific technique than on experience and correct patient selection.

Surgery is performed under general anesthesia through a small horizontal incision in the lower abdomen, close to the bikini line; it takes roughly 1–1.5 hours for one side, and somewhat longer for both sides. In our practice, reimplantation is carried out by the two pediatric urologists operating together; technical details are finalized through their joint assessment during surgery, based on the findings in the ureter and bladder.