Component separation

Conflicting recommendations for anterior or posterior release

• • Can't do both
  • Anterior release generally requires larger subcutaneous tissue flaps and increase morbidity
  • Posterior release (TAR) creates a nice retrorectus plane which is convenient for the retrorectus mesh placement

Anterior (external oblique) release.

First trialled in 1990 (Dr Oscar Ramirez). Essentially release aponeurosis of external oblique (just lateral to the edge of rectus) and elevate rectus abdominis from posterior sheath.

• • Midline laparotomy
  • Elevate subcutaneous flaps (superficial to rectus sheath) to expose linea semilunaris, and go a couple of cm further laterally
  • Preserve large periumbilical perforators
  • External oblique fascia incised 1cm lateral to linea semilunaris from above costal margin to inguinal ligament, separating EO from IO fascia

• • 1. Allows development of avascular plane between EO aponeurosis and IO muscle as far as posterior axillary line
    2. Allows for 8-10cm advancement of waist and 3-5cm in upper and lower abdomen

• • An additional 2cm can be gained if rectus muscle is elevated off the posterior sheath

Posterior component separation

introduced 2012

• • Posterior lamellar of IO is incised to achieve myofascial advancement, while transversus abdominis is incised and released from the peritoneum in the upper third of the abdomen

• • Clear abdo wall of adhesions - can't do the dissection safely with bowel adherent to anterior abdo wall
  • Use a towel to protect bowel
  • Incise peritoneum just lateral to linea alba until rectus abdominis muscle is seen

• • Posterior rectus sheath dissected free of rectus muscle until linea semilunaris is exposed (look out for neurovascular bundle just medial to LS in rectus muscle)

• • Posterior lamellar of IO is incised just medial to the neurovascular bundles, which exposes the transversus abdominis muscle in the upper third of the abdomen

• • Right angle clamp used to guide transection of the TA muscle, which exposes peritoneum (very thin layer underneath, and easy to break)

• • Once posterior rectus sheath is incised completely along its length, the TA muscle is separated from the peritoneum using appropriate traction-counter traction. Don't make holes in peritoneum - if it happens, work lateral and get behind the defect before it gets bigger. Free peritoneum out to psoas muscle if necessary.

• • In pelvis, Cooper's ligaments are exposed bilaterally, and the bladder is taken down. At the xiphoid process, the medial edge of the posterior rectus sheath is incised in a cephalad fashion towards the diaphragm.
  • Posterior rectus sheath is reapproximated using 2-0 absorbable suture
  • Mesh inserted into preperitoneal pocket and fixed with transfascial sutures
  • Drains placed over the mesh and below the fascial closure
  • Linea alba reapproximated and skin closed

Post-op

• • Analgaesia - some say epidurals
  • Drains stay in until output <30ml/24 hours - typically 3-5 days with synthetic mesh