Fibula Free Flap - Indications, Contraindications, Techniques, Benefits, and Risks

What Is a Fibula-Free Flap?

Mandibular reconstruction is a complex surgery due to its anatomical consideration and the complex nature of mandibular movements. Mandibular reconstruction helps restore and reconstruct defective bones due to ablative surgery, infection, extensive lesions, cysts, or trauma. Various methods of mandibular reconstruction include pedicle flaps, titanium reconstruction plates, and bone grafts.

The commonly used method is the free fibular flap technique. This technique comprises a vascularized free composite flap, including bone and muscle, with or without skin. It provides excellent results, both functionally and aesthetically, by restoring the defect.

The iliac crest, scapula, and radial forearm flaps are other flaps used for bony reconstruction. The free fibular flap technique was first described by Hidalgo et al. in 1989 for mandibular reconstruction. Head and neck reconstruction can be done with free fibular flaps as bone grafts, but mandibular reconstruction is difficult to perform as the fibula is a linear bone. It is difficult to achieve the mandibular shape and occlusion pattern. This technique withstands irradiation better than other methods like bone grafts and plates.

What Are the Indications for a Fibula-Free Flap?

The indications for fibula-free flaps are

• Larger bone defects of more than 6 cm in size.

• Surgical bony defects might occur due to the removal of tumors.

• Pseudoarthrosis.

• Length alterations in the limbs.

• Severe bone loss associated with chronic osteomyelitis.

• Mandibular reconstruction for correcting the mandibular defects.

• Osteonecrosis of the bone.

What Are the Contraindications for a Fibula-Free Flap?

The contraindications for free fibular flaps are

• Lower limbs with peripheral vascular disease.

• Ischemic disease in the lower limb includes deep vein thrombosis and arteriosclerosis of the fibular artery that can not provide good blood supply to the flap.

• Hypoplastic anterior tibial artery.

• Venous insufficiency.

• Previous amputation history in the lower limbs.

• Arteritis.

What Are the Techniques Used for Mandibular Reconstruction?

Steps involved in the free fibular flap technique include:

• Expose the Bone: Bone resection can be done on the exposed surface of the mandible at the lateral aspect, and then insertion and fixation of the flap can be done. A 3cm margin is needed over the osteotomy for the fixation of the plates.

• Preplating: Mark the limits after the bone resection and then fix the 3mm plate using 7 to 11mm fixation screws on the inner side of the mandible. If there is involvement of the external cortical bone, then use the inferior margin of the bone.

• Removing the Plate: The plate has been removed. Mark the plate holes and screw holes on the bone to verify the fixation during replating. This is mostly used for the permanent fixation of the plates.

• Bone Resection: A segmental mandibulectomy procedure can resect the bone with clear margins. The mandibular stump should contain at least two identifiable screw holes for reconstruction.

• Replating: The plate has been placed based on the markings of screw holes. To achieve the mandibular shape, correctly identify the markings of the plate holes and screw holes. Permanent plate fixation is done on the lateral aspect of the mandible, while pre-plating is done on the inferior margin of the mandible.

• Removing the Pre-plating: The permanent plate is kept in place by removing the pre-plating.

• Making a Template for Flap: A template can be made by shaping the plastic sheet, which can be used as a model for the flap based on the number, length, and other characteristics of the fibula.

• Shaping the Fibula: The fibula flap can be removed from the donor site, and be shaped based on the shape of the template.

• Fixing the Flap: Fix the shaped flap between the mandibular stumps to the plate using several bicortical screws. The micro anastomoses are done, and then the flap's skin is placed in the desired position with sutures.

What Are the Benefits of a Fibula-Free Flap for Mandibular Reconstruction?

The benefits of using a fibula-free flap are

• Larger bone defects can be restored using a fibula bone, which is a thin, long bone.

• The fibula can be shaped as a mandible based on the requirements.

• The flap can be obtained easily from the donor site with fewer side effects at the recipient site. It also eases the operation by allowing two surgical teams to perform surgical procedures simultaneously on the donor and recipient sites.

• Dental implants are also placed during this procedure in the bone.

What Are the Risks and Limitations Associated With a Fibula-Free Flap for Mandibular Reconstruction?

The risks associated with a fibula-free graft are

• Bleeding.

• Infection.

• Wound dehiscence.

• Fracture of the graft.

• Hematoma.

• Neurovascular damage might cause sensory or motor loss.

• Improper technique and fixation.

• A length discrepancy occurs in graft.

• Malunion or non-union of graft.

• Partial or complete free flap failure due to thrombosis of the micro anastomose vessels.

• In case of smaller fragment requirements for bone modeling, the blood supply to the intramedullary fibula bone will be reduced due to several osteotomies.

• This flap has a smaller pedicle, which makes anastomoses difficult to perform.

• If the patient has aesthetic concerns, this technique should be avoided, as it may cause scars over the lateral part of the lower limb. The patient may go for an iliac crest and lateral brachialis flap. The Iliac crest flap may cause a scar over the iliac crest, which can be covered, and the arm can cover the para-scapular scar when resting. The lateral brachialis flap produces a scar over the lateral part of the arm.

• The Fibula flap has limited skin thickness, which does not provide adequate skin paddle to reconstruct soft tissue.

What Are the Postoperative Care and Follow-up for Fibula Free Flap?

Following fibula-free flap surgery, postoperative care and follow-up are essential for tracking a patient's recovery. Scheduling routine meetings with the medical team is essential to evaluate the progress of wound healing, identify any infections or problems, and modify rehabilitation plans. Imaging tests such as CT scans or X-rays can assess fibula flap integration and bone repair. Patients need to adhere to the guidelines provided by the healthcare team for wound care, rehabilitation exercises, and medication administration. This includes keeping the wound dry and clean, avoiding physically demanding activities, and taking prescription drugs as needed.

Conclusion

A fibula-free flap is a method for mandibular reconstruction when there are defects in the mandible due to congenital malformations, tumors, cysts, or other lesions. The fibula-free flap can be shaped according to the patient's needs; thereby it helps in achieving bone integrity both functionally and aesthetically. It can provide enough bone for the reconstruction of lengthy mandibular defects.