What is a Boari flap repair?

Boari Flap Repair: A Surgical Technique for Ureteral Reconstruction

A Boari flap repair is a surgical technique that creates a full-thickness bladder flap that is swung cranially and tubularized to perform an anastomosis with the proximal ureteral segment when the distal ureter is damaged or missing. 1

Definition and Purpose

The Boari flap is a reconstructive urological procedure used when:

• The distal part of the ureter is severely injured or completely resected
• The remaining proximal ureter cannot reach the bladder for direct reimplantation
• A tension-free anastomosis is required to maintain urinary drainage

Anatomical Principles

The procedure involves:

1. Opening the bladder on its anterior surface
2. Creating a rhomboid incision to form a full-thickness bladder flap
3. Extending the flap cranially toward the proximal ureter
4. Tubularizing the flap to create a conduit
5. Performing an anastomosis with the proximal ureteral segment 1, 2

Indications

Boari flap repair is indicated in:

• Iatrogenic ureteral injuries (IUTI) of the lower third of the ureter 1
• Ureteral strictures (benign or malignant) 3
• Complete loss of distal ureter due to trauma or ischemic necrosis 4
• Situations where direct ureteroneocystostomy is not possible due to length deficiency 1

Surgical Technique

1. Bladder Mobilization: The bladder is mobilized to allow creation of the flap
2. Flap Creation: A rhomboid incision is made on the anterior bladder surface
3. Flap Extension: The full-thickness bladder flap is extended cranially
4. Tubularization: The flap is tubularized to form a conduit
5. Anastomosis: The proximal ureter is anastomosed to the tubularized flap
6. Stenting: A ureteral stent is placed to maintain patency during healing 1, 2

Combination with Psoas Hitch

• Often combined with a psoas hitch technique for additional stability
• The bladder is hitched to the psoas minor tendon to minimize tension
• This combination can allow replacement of significant ureteral length 5

Advantages

• Preserves normal urinary drainage pathway
• Avoids use of bowel segments for reconstruction
• Maintains the feasibility of future ureteroscopy in stone formers 3
• Can bridge substantial ureteral defects (up to the level of iliac vessels) 2

Surgical Approaches

The Boari flap can be performed via:

• Open surgery (traditional approach)
• Laparoscopic technique (minimally invasive)
• Robotic-assisted approach 1, 3, 6

Stent Management

• Ureteral stenting is essential following Boari flap repair
• Stents are typically left in place for 4-6 weeks after complete ureteral transection repair 7
• Foley catheter drainage is maintained for approximately 14 days 3

Outcomes and Success Rates

• Success rates for ureteral reimplantation using Boari flap can exceed 85% 2
• The technique allows correction of higher and more extensive defects than the psoas-hitch technique alone 2

Potential Complications

• Anastomotic leak
• Stricture formation
• Vesicoureteral reflux
• Urinary tract infection
• Flap ischemia or necrosis

Special Considerations

• Requires a normal bladder wall and adequate bladder capacity (>400 ml) 5
• Technical expertise is essential, particularly for laparoscopic approaches 6
• Should be referred to an experienced urological center due to technical complexity 1

The Boari flap represents an important technique in the urological reconstructive armamentarium, particularly for managing distal ureteral defects when direct anastomosis is not feasible.