Michael Carson

Department of Oral and Maxillofacial Surgery, Naval Medical Center Portsmouth, Portsmouth, Virginia, USA

A surgical procedure for harvesting a cortical, cancellous, or corticocancellous block graft from the anterior ilium.

Indications

1. When autogenous grafting is desired that requires a high ratio of cancellous to cortical bone (a high volume of osteocompetent cells)
2. Hard tissue maxillofacial defects requiring 50 mL or less of cancellous bone

Contraindications

1. Reconstruction of maxillofacial defects requiring more than 50 mL of cancellous bone
2. Patients with previous head and neck radiation involving the graft recipient site

Anatomy

• Anterior ilium: Located between the anterior iliac spine and the ilium tubercle. The ilium serves as a site for numerous muscular attachments responsible for normal gait and core stability.
• Anterior superior iliac spine: Serves as the attachment of the external abdominal oblique muscle medially and the tensor fascia lata laterally.
• Tensor fascia lata: Originates at the anterior superior iliac spine and the antero-lateral portion of the anterior iliac crest, and inserts into the iliotibial tract of the lateral thigh. The iliotibial tract (band) continues inferiorly and inserts along the lateral condyle of the tibia. Damage or excessive retraction of this muscle is the most common cause of postoperative gait disturbances.
• Iliacus muscle: Originates along the superior half of the iliac fossa (medial iliac crest). The iliacus muscle joins the psoas major muscle and inserts along the lesser trochanter of the femur.
• Sensory cutaneous nerves (3):
  • Iliohypogastric nerve (L1, L2): The lateral cutaneous branch of the iliohypogastric nerve is located overlying the ilium tubercle and is the most commonly injured nerve during an anterior iliac crest bone graft (AICBG). The iliohypogastric nerve provides sensory innervation to the skin of the pubis and lateral aspect of the buttock.
  • Lateral branch of the subcostal nerve (T12, L1): Located overlying the anterior superior iliac spine. The subcostal nerve is located medial to the iliohypogastric nerve and provides sensory innervation to the lateral buttock.
  • Lateral femoral cutaneous nerve: Located between the psoas major and the iliacus muscle, medial to the subcostal nerve. In 2.5% of the population, the lateral femoral cutaneous nerve can be found within 1 cm of the anterior superior iliac spine. The lateral femoral cutaneous nerve provides sensory innervation to the skin of the anterior and lateral thigh. Damage to this nerve may result in a meralgia paresthetica.

Anterior Iliac Crest Bone Graft (AICBG) Harvesting Technique (Medial Approach)

1. Preoperative intravenous antibiotics are administered. The patient is intubated and positioned supine on the operating room table. A hip roll is placed under the pelvis to accentuate the anterior iliac crest anatomy. Surgical markings are made to include the locations of the anterior superior iliac spine, the ilium tubercle, and the anterior iliac crest (Figure 53.1).
2. A hand is used to place medial (toward the abdomen) pressure, and the anticipated incision line is marked 2–4 cm lateral to the height of the anterior iliac crest (Figure 53.1). Incisions placed directly overlying the anterior ilium will cause postoperative pain along the beltline. Local anesthetic containing a vasoconstrictor is injected within the area of the proposed skin incision within the subcutaneous tissue.
3. The patient is prepped and draped in a sterile fashion. An iodoban antimicrobial incise drape (3M, St. Paul, MN, USA) may be used if desired.
4. A 4–6 cm skin incision is made with a #10 blade 1 cm posterior to the anterior superior iliac spine and terminating 1–2 cm anterior to the ilium tubercle.
5. The dissection proceeds through the subcutaneous tissue until Scarpa’s fascia is reached. A 4 × 4 sterile gauze is used to bluntly dissect Scarpa’s fascia (Figure 53.2) from the overlying subcutaneous fat. Prior to transversing Scarpa’s fascia, electrocautery is used to control all hemorrhaging subcutaneous vessels.
6. A #15 blade is used to transect Scarpa’s fascia. A hypovascular tissue plane is identified overlying the anterior iliac crest between the insertions of the tensor fascia lata laterally and the external and transverse abdominal muscles medially. Elevating within this hypovascular tissue plane will minimize bleeding and postoperative pain or gait disturbances. The periosteum is released, and dissection proceeds within a subperiosteal tissue plane over the medial (inner) iliac cortical plate. The iliacus muscle is identified and reflected to expose the medial iliac crest (iliac fossa).
7. A blunt retractor (i.e., a Bennett retractor) is placed to retract the musculoperiosteal layer and to protect the intra-abdominal contents during the medial approach to the anterior ileum.
8. Osteotomies are made utilizing combinations of saws, burs, and chisels based on the type of graft required (corticocancellous block or cancellous graft) and the size of the defect requiring reconstruction. Regardless of the osteotomy design, it is imperative to preserve the attachments to the anterior superior iliac spine and to maintain a minimum safe distance of 1 cm from the anterior superior iliac spine and 1–2 cm from the ilium tubercle.

9. For standard medial (inner) AICBG harvest, the author marks the proposed osteotomy site with either a sterile marking pen or electr/>

   Only gold members can continue reading. Log In or Register to continue