Anterior Approach to the Iliac Crest

Anterior Approach to the Iliac Crest is used for harvesting bone graft. Anterior iliac crest bone grafts are the most commonly used grafts in orthopedic surgery.

Position of the Patient

Place the patient supine on the operating table. Place a small sandbag under the gluteal (cluneal) area of the side from which the graft will be taken to elevate the crest and rotate it internally, making it more accessible.

Landmarks and Incision

• Landmarks:
  1. Anterior superior iliac spine.
  2. Iliac tubercle.
• Incision :
  • The length of incision depends on the amount of bone graft that is required.
  • For an extensive bone graft make an 8-cm incision parallel to the iliac crest and centered over the iliac tubercle.

See Also: Pelvic Anatomy

Internervous plane

• The crest offers a truly internervous plane because muscles either take origin from or insert onto the iliac crest, but do not cross it. 
•  The tensor fasciae latae, gluteus minimus, and gluteus medius are the muscles affected most directly by grafts taken from the anterior portion of the crest, because they originate from the outer portion of the ilium and are supplied by the superior gluteal nerve.
• The abdominal muscles take their origin directly from the iliac crest and are supplied segmentally.

Superficial dissection

• Retract the skin and identify the iliac crest. Cut down onto the iliac crest with a scalpel.
• In children, the crest still may be an avascular apophysis. If so, incise it and remove the muscle through the crest in either direction with a Cobb elevator.
• No apophysis will be present in adults.
• Take care not to carry the incision from the apophysis or iliac crest onto the anterior superior iliac spine itself; if this occurs, the origin of the inguinal ligament may be detached and an inguinal hernia may result.

Deep dissection

• The muscles may be stripped off either the inner or the outer wall of the ilium.
• Initially, cut down onto the bone using a scalpel.
• Follow the contour of the bone, sticking to it rigidly
• After coming around the corner of the crest onto the ilium, continue the dissection using blunt instruments such as a Cobb elevator.
• The muscles will come away from the bone easily.
• Alternatively, push a swab into the plane between the iliac wing and the overlying muscles.
• Using a blunt instrument, introduce more and more of the swab into the plane.
• The swab will act as a tissue expander, pushing the muscle away from the bone, while at the same time protecting the soft tissues.

Approach Extension

• The Anterior Approach to the Iliac Crest  is not classically extensile. The approach has been described in this section merely as a means of obtaining bone graft.

Dangers

The structures at risk during Anterior Approach to the Iliac Crest includes:

1. Both the crest of the ilium and the anterior superior iliac spine should be left intact to preserve the normal appearance of the pelvis.
2. If the anterior superior iliac spine is taken as graft material, the inguinal ligament might retract, causing an inguinal hernia.

References

• Surgical Exposures in Orthopaedics book – 4th Edition
• Campbel’s Operative Orthopaedics book 12th