Anterolateral retroperitoneal approach

Retroperitoneal (Anterolateral) Approach to the Lumbar Spine

Indications

   Can access L1 to sacrum
      slightly more difficult to reach L5-S1 disk space than transperitoneal approach
      bifurcation of great vessels anterior to L4 vertebral body q
  Indications
      psoas abscess drainage (without risk of postoperative ileitits)
      spinal fusion
      biopsy or resection of vertebral body
      disc replacement
      exposure of sympathetic chain (general surgery)

Position

  Place in semilateral position (45 degrees to horizontal)
      use sandbags or bean bag to hold patient at angle
      or place patient supine and tilt table
  Place left side up
      aorta is more resistent to injury than vena cava

Incision

  Make incision from
      posterior half of 12th rib to
      lateral border of rectus abdominis (midway between umbilicus and pubic symphysis)

Approach

  Approach to spine
      incise subcutaneous fat
      expose aponeurosis of external oblique muscle
      divide external oblique in line with fibers
      divide internal oblique in line with incision and perpendicular to muscle fibers
      divide transverus abdominis in line with skin incision
      bluntly disect plane between retroperitoneal fat and psoas fascia
      retract peritoneal cavity medially
          bring ureter with peritoneal cavity
      follow surface of psoas muscle to vertebral bodies
      tie off segmental lumbar arteries of aorta in the field of dissection
  L4/5 disc space
      mobilize aorta to the contralateral side
      place needle in disc and take lateral xray to identify level
  L5/S1 disc space
      work between the bifurcation of aorta
      place needle in disc and take lateral xray to identify level

Dangers

  Sympathetic chain
      lateral aspect of vertebral body
  Genitofemoral nerve
      anterior surface of psoas muscle attached to fascia 
  Segmental arteries
      segmental lumbar arteries and veins q
      aorta
  Ureter
      lies between psoas fascia and peritoneum
          attached more firmly to peritoneum
          stroke to produce peristalsis to confirm
  Superior hypogastric plexus 
      injury leads to retrograde ejaculation