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Iliac Crest-Internal Oblique Free Flap

last modified on: Mon, 01/08/2024 - 08:43

return to: Microvascular Surgery Protocols

Note: last updated before 2015

GENERAL CONSIDERATIONS

  1. Indications
    1. This flap has been used extensively for oromandibular reconstruction. It is particularly well suited for this purpose due to the natural contour of the bone, the excellent bone stock available to accept osseointegrated implants, and the utility of the internal oblique muscle in the formation of a thin immobile soft tissue closure over the bone intraorally. This last feature allows for re-creation of labial and lingual sulci that facilitate the use of either tissue-borne or implant-retained dental prostheses. The iliac crest flap has also been used in maxillary reconstruction.
  2. Contraindications
    1. See Microvascular Surgery General Considerations. Flap-specific contraindications include prior inguinal hernia or abdominal surgery in the region of the flap harvest.
    2. Prior vascular surgery involving the femoral vessels is a contraindication.
    3. Although not an absolute contraindication, elevation of this flap is extremely difficult in the severely obese patient. If a large intraoral soft tissue defect involving the tongue will be present in addition to the bony defect, a scapular or fibula flap may be preferred. An alternative would be the use of the iliac crest with a second free flap for soft tissue closure.
  3. Pertinent Anatomy
    1. The bone and cutaneous paddle are based on the deep circumflex iliac artery (DCIA) and vein (DCIV). These vessels arise from the external iliac vessels. The vascular pedicle of the internal oblique muscle is the ascending branch of the deep circumflex iliac vessels. This branch is located approximately 2 cm medial to the anterior superior iliac spine (ASIS) and courses along the medial surface of the muscle. The ascending branch takes off deep to the transversus abdominis muscle. The musculocutaneous perforators emerge through the transversus abdominis, internal oblique, and external oblique muscles along the iliac crest. The greatest concentration of these vessels is approximately 6 to 8 cm posterior to the ASIS. The skin paddle is obliquely oriented with its major axis along the iliac crest. The blood supply to the iliac crest bone is derived from the deep circumflex iliac vessels coursing along the inner aspect of the iliac crest in a groove between the iliacus and transversus abdominis muscles. This is about 2 cm from the top of the crest.

PREOPERATIVE PREPARATION

  1. Evaluation
    1. Exclude previous surgical or traumatic injury to the region of the vascular pedicle or flap through careful history and physical examination.
  2. Potential Complications
    1. See Microvascular Surgery General Considerations. Flap-specific complications include postoperative hernia, prolonged painful ambulation, and potential numbness in the distribution of the lateral femoral cutaneous nerve. Most patients will have a postoperative ileus for several days. All patients should be instructed regarding the need for involvement in a physical therapy program postoperatively to get them up and ambulating after the first postoperative day.

NURSING CONSIDERATIONS

  1. Room Setup
    1. See Free Flap Room Setup
  2. Instrumentation and Equipment
    1. Standard
      1. Major Instrument Tray 1, Otolaryngology
      2. Major Instrument Tray 2, Otolaryngology
      3. Bipolar Forceps Trays
      4. Microsurgery Instrument Tray, Otolaryngology
      5. Hall Micro Sagittal Saw Tray (Pneumatic)
      6. Retractor Tray, Large
    2. Special
      1. Padgett Dermatome Instrument Tray
      2. Bien Otologic Electric Drill Tray
      3. KLS Oto Trauma Implant - Instrument Tray
      4. KLS Free Flap Implant - Instrument Tray or Midas Rex Drill Tray
  3. Medications (specific to nursing)
    1. Heparin sodium injection, 1,000 unit per ml, 10 ml vial
    2. Papaverine injection, 60 mg per 2 ml, 2 ml ampule x 2
    3. PhysioSol irrigation solution, 500 ml (be sure the PhysioSol is in the warmer in sufficient time to be warm when the surgeon requests it)
  4. Prep and Drape
    1. Standard prep, 10% providone iodine: head and neck as needed for the ablative procedure including the chest. The abdomen should be prepped from the upper thigh to the chest. The abdominal prep should extend from 6 cm medial to the midline of the abdomen to the midline of the back.
    2. Drape
      1. Drape the entire operative field from nipples to upper thighs, side to side with towels
      2. Long sheet above and long sheet below
      3. Split sheet
  5. Drains and Dressings
    1. Abdominal binder
    2. 10 mm flat suction drains
  6. Special Considerations
    1. Heparin sodium injection 5,000 units in sodium chloride 0.9% 500 ml in syringe, Luer tip 5 cc syringe with 24-gauge IV cannula is used to irrigate vessels.
    2. Papaverine 60 mg in 500 cc sodium chloride 0.9% in a Luer tip 10 cc syringe with 18-gauge IV cannula will be used topically to irrigate for vasospasm.
    3. Use all measures to keep body temperature at least 37.6°C (warming blanket, room temperature).
    4. See Skin graft protocol if necessary for procedure.
    5. See Microvascular Surgery General Considerations.

ANESTHESIA CONSIDERATIONS

  1. General
    1. Patient is in supine position with Mayfield headrest.
    2. The arms should be tucked and the table turned 180° from the anesthesiologist.
    3. A foam cushion should be placed under ipsilateral buttock to elevate hip.
  2. Specific
    1. The anesthesia tubing and arterial and IV lines should all be contralateral to the side of flap harvest.
    2. Advise the anesthesiologist that nitrous oxide should not be used during the case.

OPERATIVE PROCEDURE

  1. Mark out location of inguinal ligament, ASIS, pubic tubercle, iliac crest, and skin paddle over iliac crest along an axis from the ASIS toward the angle of the scapula.
  2. Initial incision should extend from the midaxillary line to the approximate location of the femoral vessels. The superior margin of the skin paddle is incorporated into the incision. Separate the external oblique fibers along the axis of the muscle 3 cm above the iliac crest to expose the entire internal oblique.
  3. Incise the lateral, superior, and medial borders of the internal oblique and elevate it off of the transversus. The ascending branch will be identified running on the medial surface of the muscle.
  4. Trace the ascending branch through the transversus to its origin from the DCIA. Divide the transversus 3 cm from the upper iliac crest. Dissect the DCIA and DCIV to their origins from the external iliac vessels.
  5. Detach the fascia lata, sartorius, and gluteus from the lateral aspect of the iliac crest. Identify the course of the DCIA running on the inner surface of the iliac crest. Incise through the iliacus muscle down to bone 2 cm inferior to the vessel and roughly parallel to it. Use the oscillating saw or Midas-Rex to make the bone cuts. The flap is now pedicled on the vascular pedicle.
  6. After delivery of the flap, meticulous hemostasis is obtained. The transversus muscle and transversalis fascia are sutured to the iliacus muscle and inguinal ligament. The external oblique is sutured to the gluteus fascia and fascia lata. The skin is closed over one or two 10 mm fully-perforated suction drains. An abdominal binder is placed at the end of the case.

POSTOPERATIVE CARE

  1. The patient should be at bedrest for approximately 24 hours.
  2. Limited ambulation with the assistance of a physical therapist begins on postoperative day 2 or 3.
  3. The patient should wear the abdominal binder for two weeks.
  4. The patient should be cautioned against heavy lifting for six weeks.

REFERENCES

Urken ML, Vickery C, Weinberg H, et al. The internal oblique-iliac crest osteomyocutaneous free flap in oromandibular reconstruction. Arch Otolaryngol Head Neck Surg. 1989;115:339-349.

Urken ML, Vickery C, Weinberg H, et al. The internal oblique-iliac crest otseomyocutaneous microvascular free flap in head and neck reconstruction. J Recon Microsurg. 1989;5:203-214.

Urken ML, Weinberg H, Vickery C, et al. The combined sensate radial forearm and iliac crest free flaps for reconstruction of significant glossectomy-mandibulectomy defects. Laryngoscope. 1992;102:543-558.