Perioperative management - Component separation according to Ramirez

The reconstruction of the abdominal wall in complex incisional hernias or the presence of a laparostoma presents a particular challenge. A "loss of domain" represents the extreme form of a volume displacement of the intestines.

Complex hernias are considered to be abdominal wall hernias with defect widths of more than 10 cm, recurrent incisional hernias after mesh implantation (mesh edge herniation, mesh tear, mesh rupture), hernias after flap transfer (denervation, donor site defects), and multiple recurrences.

The abdominal wall defect after laparostoma represents a special situation. An abdominal wall closure has never occurred here. Complicating matters, there is no natural skin in the area of the abdominal wall defect, but rather a split-thickness skin graft. There is also no hernial sac helpful for reconstruction. The closure of the skin can pose an additional problem.

In principle, the indication for repair of even a complex hernia is given. Patients lack ventrally stabilizing elements of the trunk musculature. Patients with such unstable abdominal walls complain of postural problems with back pain. Physically demanding activities and sports are severely restricted to impossible. An intact ventral abdominal wall is of great importance for physiological processes such as breathing and defecation.

Furthermore, the abdominal wall defect and the extra-abdominal organ volume will continue to increase. The reconstruction of the abdominal wall is ultimately performed to prevent increasing morbidity.

To achieve a fascial closure in the midline for these hernias, an abdominal wall component separation is usually required.

With the anterior component separation ("Ramirez") presented here, midline defects with a width of up to 20 cm periumbilically, up to 8 cm epigastrically, and up to 6 cm suprapubically can be closed by separating parts of the lateral abdominal wall. The technique allows for a tension-free closure with a dynamically competent abdominal wall.

Due to the broad detachment of the subcutaneous tissue with the risk of destroying perforating vessels (blood supply to subcutaneous tissue and skin through the deep epigastric vessels) and the consequently high rate of wound healing disorders, hematomas, and seromas, this technique is now considered only as a second-choice procedure. The posterior component separation, which leads to a release in the area of the transversus muscle, is favored; additionally, the mesh bed can be extended laterally, dorsally, and retrocostally.

The reconstruction according to Ramirez was described in the original work without mesh augmentation. The results in the literature favor the simultaneous implantation of a retromuscular mesh.

In the demonstrated case, after small bowel perforation and peritonitis, a monstrous abdominal wall defect of 20 cm width occurred. The defect extends from subxiphoidal to the symphysis and is closed by an abdominal wall plasty using component separation and subfascial mesh augmentation.

The indication for hernia repair in patients with liver cirrhosis and ascites should be critically evaluated, and preoperative optimization of liver function should be considered if necessary. In cases of severe coagulation disorders (Quick < 50%, PTT > 60 s, platelets < 50 /nl) and pronounced portal hypertension with caput medusae, surgery should be avoided due to the risk of uncontrollable bleeding from abdominal wall vessels.

A good respiratory condition, not compromised by acute infections, is also important. In the case of respiratory infections, elective surgery should definitely be postponed.

• The abdominal wall hernia is a clinical diagnosis and can be well recognized in a standing patient. It is advisable to additionally examine the patient in a relaxed, lying position. When the patient is asked to lift the upper body, the fascial edge, the extent of the fascial defect, and the surrounding muscles can usually be assessed in reducible incisional hernias.
• To determine the defect location, the extent of the defect, and to depict the abdominal wall anatomy, CT is the best diagnostic procedure, alternatively an MRI.
• In cases of previous incisional hernia repairs, a corresponding surgical report is often helpful, especially if a mesh repair has already been performed. Here, in addition to the exact surgical technique (extra- or intraperitoneal mesh placement, augmentation or bridging of the fascial defect), the type of mesh material is particularly important.
• In extensive findings, thorough cardiopulmonary function diagnostics are recommended due to the increase in pressure after repositioning the protruded intestines.

For better characterization of the present hernia, the EHS classification should be used.

Classification of primary ventral hernias

 Classification of secondary ventral hernias (incisional hernias)

The classification of secondary abdominal wall hernias is initially based on a medial or lateral defect location in the abdominal wall.

The defect location of medial hernias is then more precisely delineated as subxiphoidal, epigastric, umbilical, infraumbilical, and suprapubic. Laterally, the defects are classified as subcostal, lateral, iliac, and lumbar.

Further consideration is given to the defect width of incisional hernias: W1 (< 4 cm), W2 (4 - 10 cm), and W3 (> 10 cm).

If there are multiple hernia defects (mesh hernia, Swiss-cheese hernia), their size is determined by the total length and width.

• Control of infection situations
• Medication management in immunosuppression or anticoagulation
• Control of cardiac and pulmonary risk factors
• Bowel evacuation is advisable, preoperative bowel lavage is not strictly necessary.
• Single-shot antibiotic i.v. perioperatively (due to the use of foreign material/mesh) possibly continuation of therapy in case of intraoperative signs of inflammation or bacterial contamination.
• In advanced eventration of the intestines, additional conditioning of the abdominal wall should be discussed. The following options exist:
  • progressive pneumoperitoneum: Stretching of the abdominal wall by insufflation of air through a catheter into the abdomen. Central venous catheters, small pleural catheters, or similar are used, as no standardized instrumentation exists. This catheter is inserted through the abdominal wall in a primary procedure. The catheters should be equipped with a bacterial filter and a closure system. Depending on the scheme, room air is applied daily into the abdomen using a large-bore syringe. The preoperative hospitalization of the patient is a disadvantage.
  • Injection of botulinum toxin into the lateral abdominal muscles 4 weeks preoperatively.
  • Intraoperative fascial traction, where the lateral abdominal muscles are mechanically stretched intraoperatively, traction duration 30 min with 14 - 20 kg.
  • An average length gain of 4 - 5 cm per side is reported for all methods.

In the example, no conditioning of the abdominal wall was performed.

General:

• Pneumonia
• Bleeding, rebleeding, hematoma
• Wound infection/wound healing disorder
• Thrombosis/embolism
• Excessive scar formation
• Injuries to adjacent structures such as nerves, vessels, bladder, and bowel

Specific:

• Implantation of synthetic material
• Reduced load-bearing capacity, especially during the first 3 months
• Altered shape of the abdominal wall, depressions due to lack of subcutaneous tissue
• Abdominal wall paralysis
• Nerve injury/chronic pain
• Seroma (usually present, mostly without therapeutic consequence)
• Infection of the implant with the consequence of needing to remove it
• Bowel passage disorder (atony/ileus)
• Recurrent hernia
• Bowel perforation
• Follow-up surgeries
• Lethality