What are the key anatomical considerations for Inguinal Posterior Open Mesh (IPOM) repair?

Key Anatomical Considerations for IPOM Repair

For intraperitoneal onlay mesh (IPOM) repair of inguinal hernias, the key anatomical considerations include proper mesh placement with at least 5 cm overlap of the defect, careful dissection of important structures, and appropriate mesh fixation to ensure optimal outcomes.

Essential Anatomical Structures

When performing IPOM repair, surgeons must be aware of and properly manage several critical anatomical structures:

• Peritoneal Space: The IPOM technique involves placing mesh directly in the intraperitoneal space, which differs from the preperitoneal placement used in other techniques 1

• Hernia Defect Margins: Complete visualization and measurement of the entire defect is essential, with the mesh needing to extend at least 5 cm beyond all margins of the defect 2

• Critical Structures Requiring Dissection:

  • Falciform ligament
  • Ligamentum teres hepatis
  • Prevesical space (must be adequately opened to allow proper mesh fixation) 2

• Vascular Considerations: Care must be taken to avoid injury to:

  • Inferior epigastric vessels
  • Testicular vessels in males
  • Round ligament in females

Mesh Selection and Placement

The choice and placement of mesh are critical considerations:

• Mesh Requirements:

  • Must induce strong and rapid incorporation on the parietal (abdominal wall) side
  • Should prevent adhesions on the visceral (bowel) side
  • Should allow overlap of multiple meshes for larger defects 2
  • Composite meshes with anti-adhesive properties on the visceral side are preferred 3

• Placement Technique:

  • The mesh must be completely flat against the peritoneum
  • Edges should not be curled or wrapped
  • Firm adherence is necessary to prevent displacement when pneumoperitoneum is released 4

Fixation Methods

Proper fixation is essential for successful IPOM repair:

• Traditional Fixation:

  • Tacks or staples are commonly used
  • Sutures may be used for additional security

• Alternative Fixation:

  • Fibrin glue has been used successfully in some cases 3
  • The "contraposition and alignment" technique involves pre-marking fixation positions to ensure optimal placement 4

Potential Complications Related to Anatomy

Understanding anatomical considerations helps prevent complications:

• Mesh-Related Complications:

  • Adhesive intestinal obstruction
  • Enterocutaneous fistula
  • Mesh erosion into organs 5

• Technical Complications:

  • Seroma formation (reported rate 0.4%)
  • Hematoma (reported rate 1.6-1.86%)
  • Wound infection (reported rate 0.4-1.6%) 1

Advantages of Preperitoneal Placement

It's worth noting that some surgeons have developed techniques to place mesh in the preperitoneal plane (PPOM) rather than intraperitoneally to reduce mesh-related complications 5. This represents an evolution of the traditional IPOM approach.

Surgical Outcomes

Understanding the anatomical considerations impacts surgical outcomes:

• Recurrence Rates:

  • Open IPOM techniques have shown recurrence rates between 0-61% (mean 12.6%) 6
  • Proper mesh overlap of at least 5 cm and appropriate fixation can significantly reduce recurrence 2

• Operative Time:

  • With proper anatomical understanding and technique, IPOM repair can be performed efficiently (mean operative time of 10 minutes in some studies) 3

Pitfalls to Avoid

• Inadequate Mesh Overlap: Failure to provide at least 5 cm overlap in all directions increases recurrence risk 2

• Improper Mesh Placement: Can lead to intestinal obstruction and mesh infection 4

• Incomplete Dissection: Failure to adequately dissect structures like the falciform ligament can lead to poor mesh incorporation 2

• Mesh Selection Errors: Using non-composite mesh can increase adhesion risk and related complications 3

By understanding and respecting these anatomical considerations, surgeons can optimize outcomes for patients undergoing IPOM repair for inguinal hernias.