Preperitoneal Space as an Ideal Layer for Endoscopic Sublay Repair of Ventral Hernia: A Technical and Clinical Review

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Preperitoneal Space as an Ideal Layer for Endoscopic Sublay Repair of Ventral Hernia: A Technical and Clinical Review

The management of ventral hernias has evolved considerably, with traditional approaches like open sublay repair and laparoscopic intraperitoneal onlay mesh (Lap-IPOM) repair being supplemented by newer minimally invasive techniques. Endoscopic sublay repair (ESR), particularly through totally extraperitoneal (TES) and transabdominal (TAS) approaches, has emerged as a promising alternative. This article explores the technical feasibility, outcomes, and rationale for utilizing the preperitoneal space as the primary layer for ESR in small ventral hernias, based on a multicenter retrospective study of 62 patients in China.

Historical Context and Rationale for Preperitoneal Sublay Repair

Open sublay repair, which involves retrorectus (retromuscular) mesh placement, and Lap-IPOM repair, where mesh is positioned intra-abdominally, have been cornerstone techniques for ventral hernia repair. However, these methods carry inherent limitations: open sublay repair is associated with wound-related complications, while Lap-IPOM risks intra-abdominal organ injury and long-term mesh complications, such as adhesion formation and fistula. ESR, by contrast, aims to combine the advantages of sublay mesh positioning with minimally invasive access, minimizing tissue disruption and preserving anatomical integrity.

The preperitoneal space, located between the posterior rectus sheath and the peritoneum, offers unique advantages over the retrorectus space. Dissection in this layer avoids cutting through musculoaponeurotic structures (e.g., rectus sheath or transversus abdominis), thereby reducing iatrogenic damage. Additionally, the preperitoneal space’s natural continuity across abdominal regions enables extensive separation without compromising structural stability, making it particularly suitable for small hernias (e.g., umbilical, linea alba, or small incisional defects).

Endoscopic Sublay Repair: Technical Approaches and Innovations

Two ESR methodologies were evaluated:

  1. Totally Extraperitoneal Sublay (TES): This approach avoids entering the peritoneal cavity entirely, reducing risks of intra-abdominal complications.
  2. Transabdominal Sublay (TAS): Utilized in selected cases, TAS employs robotic assistance to facilitate precise dissection of the thin peritoneum from the rectus sheath.

Surgical Procedure: Key Technical Steps

  1. Trocar Arrangement:

    • For midline defects (M1–M3 regions, spanning the upper to lower midline), a lower abdominal access point was created by incising the linea alba above the pubis. Two 5-mm trocars were placed laterally [Figure 1B], followed by cephalad dissection along the posterior rectus sheath.
    • Lateral defects (M4–M5 and L3 regions) employed unilateral or bilateral trocar configurations [Figure 1C–D], while lumbar hernias (L4) required lateral decubitus positioning and retroperitoneal dissection between the transversus abdominis and Gerota’s fascia [Figure 1N–Q].
    • Complex defects crossing multiple regions necessitated customized trocar placements to ensure adequate mesh overlap [Figure 1F].

  2. Preperitoneal Space Dissection:

    • Midline Defects: Starting from the lower abdomen, blunt dissection advanced cephalad, carefully identifying the Douglas line to avoid peritoneal tears. The hernia sac was either reduced intact [Figure 1J] or transected [Figure 1K], followed by suturing of residual peritoneum. At the umbilicus, structures like the ligamentum teres hepatis and urachus were severed to prevent necrosis [Figure 1L].
    • Lateral Defects: Dissection along the transversus abdominis required meticulous separation of the retroperitoneal fat from the muscle fascia to avoid nerve injury (e.g., iliohypogastric/ilioinguinal nerves) [Figure 1P].

  3. Defect Closure and Mesh Placement:

    • Defects were closed using barbed sutures or transfascial stitches [Figure 1S]. Mesh sizing depended on the dissected preperitoneal space, with coverage extending at least 5 cm beyond the defect margin. Polypropylene or composite meshes were employed, tailored to the hernia’s location and size.

  4. Drainage Strategy:

    • Closed suction drains were routinely placed to eliminate dead space, reduce seroma risk, and enhance mesh incorporation. Exceptions were made for limited dissections with minimal contamination.

Clinical Outcomes and Challenges

The study included 62 patients with small ventral hernias (primary or incisional) treated between 2016–2020. Key findings included:

  • Success Rate: 56/62 (90.3%) completed preperitoneal TES repair. Failures (6 cases, all midline defects) resulted from extensive peritoneal tears, necessitating conversion to Lap-IPOM (2 cases) or conventional TES (4 cases).
  • Complications:
    • Seroma: Observed in 8 patients (14.3%), all resolving spontaneously within 2–4 months.
    • Wound Events: Two cases of delayed healing required debridement.
    • Chronic Pain: None reported at a median follow-up of 8 months (range: 3–45 months).
    • Recurrence: No recurrences were observed.

Critical Technical Challenges

  • Peritoneal Tear Management: Minor tears were managed by extending dissection to isolate the damaged area, followed by delayed suturing. Major tears often necessitated procedure conversion.
  • Anatomical Variability: Dissection near the diaphragm (for upper defects) and lumbar regions demanded careful identification of peritoneal reflections and neurovascular structures.

Conceptual Advancements: Total Visceral Sac Separation (TVS)

The study introduced the novel concept of TVS, likened to “peeling an eggshell” to mobilize the entire peritoneal sac. While complete TVS is unnecessary clinically, the principle underscores the preperitoneal space’s expansibility and continuity. TVS enables extensive mesh coverage while preserving musculoaponeurotic integrity, particularly advantageous for complex or recurrent hernias.

Indications and Limitations

Current evidence supports preperitoneal TES for:

  • Primary Ventral Hernias: Umbilical, epigastric, and small linea alba defects.
  • Small Incisional Hernias: Defects <5 cm in diameter.
  • Lumbar Hernias: Avoids colonic mobilization required in laparoscopic transabdominal repair.

Limitations include:

  • Learning Curve: Mastery of preperitoneal dissection requires proficiency in laparoscopic tissue handling and anatomical recognition.
  • Defect Size: Larger hernias (>5 cm) may require retrorectus or hybrid approaches for adequate reinforcement.

Conclusion

Endoscopic sublay repair via the preperitoneal space represents a paradigm shift in ventral hernia management. By combining minimally invasive access with anatomical preservation, TES achieves favorable outcomes in small hernias, minimizing wound morbidity and mesh-related complications. Refinements in dissection techniques, alongside advancements like robotic-assisted TAS, promise to expand indications and improve reproducibility. Future studies should validate long-term efficacy and explore TVS applications in complex hernia scenarios.

doi.org/10.1097/CM9.0000000000001884

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