What is the significance of the myopectineal orifice of Fruchaud in minimally invasive surgery (MIS) hernia repair?

Myopectineal Orifice of Fruchaud in Minimally Invasive Hernia Repair

Anatomical Definition and Clinical Significance

The myopectineal orifice (MPO) of Fruchaud represents the entire weak area of the groin where all inguinal and femoral hernias occur, and complete coverage of this anatomical space with mesh is essential for preventing recurrence in minimally invasive hernia repair. 1

The MPO is bounded by:

• Superiorly: Internal oblique and transversus abdominis muscles
• Inferiorly: Cooper's ligament and superior pubic ramus
• Medially: Rectus abdominis muscle and lateral border of rectus sheath
• Laterally: Iliopsoas muscle 1

Understanding this anatomical concept is critical because it unifies all groin hernias (direct, indirect, and femoral) as defects within a single anatomical space, rather than treating them as separate entities 1.

Critical View of the MPO (CVMPO)

The Critical View of the Myopectineal Orifice must be achieved during minimally invasive repair (TAPP, TEP, ETEP, RTAPP) to ensure safe and complete dissection. 1

The CVMPO requires visualization of seven key anatomical landmarks:

• Pubic symphysis
• Cooper's ligament
• Iliac vein
• Direct hernia orifice (medial space)
• Deep inguinal ring (lateral space)
• Triangle of Doom (between vas deferens and gonadal vessels)
• Iliopsoas muscle 2

This concept parallels the critical view of safety in laparoscopic cholecystectomy and serves the same purpose: preventing complications and ensuring complete repair 1.

Mesh Size Requirements Based on MPO Dimensions

Mesh dimensions must be based on intraoperative MPO measurements, with larger meshes required for defects ≥3 cm to prevent recurrence. 3

Evidence-Based Mesh Sizing:

For hernias with defects <3 cm:

• Recommended mesh size: 13.2 × 10.4 cm minimum 3
• This is derived from the 95th percentile MPO measurements (9.2 × 6.4 cm) plus 2-3 cm overlap on all sides 3

For hernias with defects ≥3 cm:

• Recommended mesh size: 15.6 × 13.0 cm minimum 3
• Based on 95th percentile measurements of 9.6 × 7.0 cm with adequate overlap 3

Gender Differences in MPO Anatomy:

Males: MPO is square-shaped, averaging 7.6 × 7.6 cm 4

Females: MPO is wider than tall, averaging 8.1 × 5.3 cm 4

A 10 × 8 cm mesh provides adequate coverage for both genders in most cases, covering the entire MPO including the infraligamental portion in females and the weak inguinal area in males 4.

Clinical Implications for Recurrence Prevention

Insufficient MPO coverage is a critical risk factor for hernia recurrence, with recurrence rates as low as 0.2-0.7% when appropriate mesh sizing based on MPO measurements is used. 3, 5

Key Technical Points:

• All groin hernia recurrences occur within the MPO area, making complete coverage mandatory 5
• The mesh must extend at least 2-3 cm beyond all MPO borders to account for mesh shrinkage and tissue movement 3
• Mesh placement should cover the entire weak area cranial to the inguinal ligament, which averages 4.5 cm in height 4

Advantages of MPO-Based Approach:

• Unified anatomical framework: Treats all groin hernias (direct, indirect, femoral) through one comprehensive repair 1
• Reduced complications: Smaller, appropriately-sized meshes covering only the MPO (rather than oversized meshes) minimize future complications with urogenital or vascular procedures 5
• Lower recurrence rates: Studies show 0.7% recurrence with MPO-based mesh sizing versus historical rates of 8-57% with inadequate coverage 3, 5

Practical Application in MIS Repair

The MPO concept should guide every step of minimally invasive groin hernia repair, from initial dissection to final mesh placement. 1

Surgical Algorithm:

1. Complete dissection to visualize all seven CVMPO landmarks 1, 2
2. Measure the MPO intraoperatively in both horizontal and vertical dimensions 3
3. Assess defect size: Categorize as <3 cm or ≥3 cm 3
4. Select appropriate mesh based on measurements (13.2 × 10.4 cm vs 15.6 × 13.0 cm minimum) 3
5. Position mesh to cover entire MPO with 2-3 cm overlap on all borders 3, 4

Common Pitfalls to Avoid:

• Inadequate lateral dissection: Failure to identify the iliopsoas muscle and lateral border of the MPO leads to incomplete coverage 1
• Undersized mesh selection: Using standard small meshes without measuring the MPO increases recurrence risk 3
• Incomplete CVMPO: Proceeding with mesh placement before achieving clear visualization of all landmarks risks injury to vessels in the triangle of Doom 1, 2