What is the Wallace technique (Wallace 1) for tension‑free uretero‑ileal anastomosis in ileal conduit urinary diversion?

Wallace Technique for Uretero-Ileal Anastomosis

The Wallace technique (Wallace 1) is a method of creating a tension-free uretero-ileal anastomosis in ileal conduit urinary diversion by spatulating both ureters along their posteromedial walls, joining them together to form a single wide ureteral plate, and then anastomosing this plate to the opened end of the ileal conduit in a side-to-side fashion.

Technical Description

The Wallace 1 technique involves the following key steps:

• Both ureters are spatulated along their posteromedial walls for approximately 1-2 cm
• The medial edges of both spatulated ureters are sutured together using running absorbable sutures to create a single wide ureteral plate
• This combined ureteral plate is then anastomosed to the opened end of the ileal conduit in a side-to-side fashion
• The anastomosis creates a wide, tension-free mucosa-to-mucosa connection between the ureters and bowel 1

Modified Wallace Technique

A modified version has been described that includes eversion of the ureteral plate and bowel mucosa edges, which are anastomosed together in running fashion, while the outer anastomotic wall is augmented with sero-serosal interrupted sutures 2. This modification has demonstrated significantly lower anastomotic stricture rates (3% vs 12%) and leakage rates (8.5% vs 17%) compared to traditional techniques 2.

Clinical Outcomes

Stricture Rates

Recent evidence shows nuanced outcomes:

• Overall stricture rates are similar between Wallace and Bricker techniques in general populations 3, 4
• Wallace demonstrates lower stricture rates specifically in patients undergoing ileal conduit urinary diversion (OR 0.35; 95% CI 0.19-0.64) 3
• Wallace shows reduced strictures in patients without prior radiotherapy (OR 0.29; 95% CI 0.14-0.61) 3
• Critical caveat: When strictures occur with Wallace technique, they are more likely to be bilateral, affecting both renal units simultaneously (15 bilateral strictures in Wallace vs 1 in Bricker) 4

Additional Benefits

• Reduced hydronephrosis compared to alternative techniques (OR 0.37; 95% CI 0.17-0.79) 3
• Appropriate for both adults and children, and can be used for primary or revision anastomoses 5

Key Surgical Principles

The fundamental principles for proper ureteric reconstruction that apply to Wallace technique include 1:

• Good vascular supply - minimize ureteral devascularization during mobilization
• Adequate drainage - ensure proper stenting and drainage to prevent urinoma
• Wide spatulated tension-free mucosa-to-mucosa anastomosis - the hallmark of the Wallace approach

Clinical Decision-Making

Choose Wallace technique when:

• Performing ileal conduit urinary diversion (not neobladder) 3
• Patient has no history of pelvic radiotherapy 3
• Both ureters are available and of adequate length
• Surgeon has expertise with the technique

Exercise caution with Wallace when:

• Patient has received prior pelvic radiotherapy - consider alternative techniques as radiation is an independent predictor of stricture formation 4
• Risk tolerance for bilateral complications is low - remember that Wallace converts two renal units into one functional unit, so strictures affect both kidneys simultaneously 4

Common Pitfalls

• Inadequate spatulation leads to narrow anastomosis and increased stricture risk
• Excessive ureteral mobilization compromises blood supply
• Tension on the anastomosis defeats the primary purpose of the technique
• Failure to recognize that bilateral involvement occurs more frequently with Wallace, requiring more aggressive monitoring of both renal units 4