A long-tunnel modification of the combined principle after Leadbetter and Clarke as true antireflux uretero-ileal anastomosis.

The aim of this study, involving 25 female mongrel dogs, was to develop a technique of ureteroileal anastomosis that would 1) avoid the danger of ureteric obstruction and urinary extravasation and 2) prevent reflux, even when exposed to extreme pressures. The combined principle, developed ny Leadbetter and Clarke, offers 3 theoretically possible modifications that were successively applied to the ileal conduit. The technically simplest one as described by Kelalis and the long-tunnel-modification of the Leadbetter-Clarke technique, resulted in ureteric obstruction and high-pressure reflux, respectively, in a high percentage. The last modification of the combined principle, not described before, allows the ureter to develop free peristalsis, covered by ileal mucosa only and unimpeded by any muscular tension. Twelve renal units implanted according to this last technique were fully protected from reflux when subjected to a pressure of 25 cm. of water. High-pressure reflux was observed in 2 renal units only. When these 12 renal units were compared with 12 renal units implanted into the same ileal conduit accordingly to Cordonnier, a statistically significant difference as to the pyelonephritic involvement of the corresponding kidneys could be established with preponderance to the inflammatory changes on the refluxing side (p less than 0.05).