Case 1: Mandible Reconstruction with a Free Fibula Graft
Authors: Mette Hørberg, consultant in oral and maxillofacial surgery, Frederik Gulmark Hansen, med.stud., Magnus Balslev Avnstorp MD and Jytte Buhl, consultant in oral and maxillofacial surgery
Before and after
Procedure
Initially, a tracheostomy procedure is performed under general anaesthesia, providing air passage through a tube on the anterior neck, when the usual route is obstructed or impaired during and after surgery. The tracheostomy will be either temporary or permanent. The tube is inserted in a window of removed tracheal ring number 3-4.
Through a transmandibular approach, a mandibulotomy, is then carried out. See the steps below.
Step 1: Cervical incision
The standard cervical incision is made superiorly in the midline vertical plane through the vermilion border of the lower lip, lip-splitting, continuing down the neck
- Often a Z-plasty is created in the submental area to prevent scar contracture in the area of maximal tension. This is done by a head and neck surgeon.
Step 2: Cutting guide
The oral maxillofacial surgeon subsequently applies a cutting guide corresponding to the affected area attached to healthy tissue, for example the condylar process and the symphysis region if unilateral, depending on the orientation of the tumor.
Step 3: Drill holes
Using the cutting guide, drill holes are made for the reconstruction plate.
Step 4a: Mandible dissection (lateral view)
The mandible is subsequently dissected, and the diseased bone removed after which the cutting guide is removed.
Step 4b: Mandible dissection (medial view)
The mandible is subsequently dissected, and the diseased bone removed after which the cutting guide is removed.
The Neck dissection is then carried out, unilateral or bilateral depending on the gradation of the tumor, and the recipient vessels are exposed.
The plastic surgeon harvests the fibula bone, with a skin paddle if required with the pedicle – peroneal artery and its venae commitans. The septocutaneous perforators to the skin which travel along the posterior intermuscular fascia are identified and preserved.
Step 5: Fibula cutting guide
A cutting guide is attached to the fibula , and the osteotomy at each end of the fibula is performed, creating the projected angles and lengths of the transplant as required after the oral resection.
- Corresponding holes for the reconstruction plate are made.
Step 6: Application of reconstruction plate
The guide is removed, and the reconstruction plate is applied to the fibula.
Step 7a: Insertion of dental implants (lateral view)
The dental implants are inserted into the graft for later prosthetic rehabilitation
Step 7b: Insertion of dental implants (top view)
The dental implants are inserted into the graft for later prosthetic rehabilitation
Step 8a: Transplantation (model)
Above is a model showing how the transplant should appear in the patient when the surgery is finished.
Step 8b: Transplantation (actual)
The peroneal vessels are then released from the donor site, and the fibula is transplanted to the mandible and osteosynthesized
Time of ischaemia is registered, and the harvested pedicle vessels are then anastomosed to a corresponding artery and vein in the neck. Most commonly the superior thyroid artery and the external jugular vein on the affected side are exposed as recipient vessels to the fibula graft. Alternatively, the facial artery and tributaries of the internal jugular vein can be used. Ischaemia ends when the artery has been anastomosed to the recipient artery.
Step 9: Closure
When hemostasis is achieved, blood flow through the free flap is checked, after which suturing is performed intra-orally and extra-orally and a drain installed at the neck.
The leg wound is closed directly whenever possible, alternatively primary closure with a split thickness skin graft to replace the area of the harvested skin paddle may be required. A dressing is then applied to the leg and the foot placed in a slight dorsiflexion.
Step 10: Result
The patient should remain tracheostomized postoperatively as there is a risk of postoperative oedema causing obstructing the airway.
- Do not suture the anastomosis under tension, try to avoid significant redundancy, and make certain the vessels are not kinked.
- The venae commitans around the peroneal artery often have complex venous interconnections between the two veins. The microsurgeon should be mindful of this difference when preparing the vessels for microvascular anastomosis.
- The use of surgical drains requires caution. A suction drain in the neck might cause impingement on the vessels, causing pedicle thrombosis. Drains should always be sutured in position to avoid drain migration and vessel compression.
- 5-7 % will experience inadequate vascularity, and flap salvage surgery will be needed – worst case the transplant will be lost.