A Step-by-Step Approach to Free Fibula Flap Mandible Reconstruction of Mandibular Pathologic Fractures: A Pictorial Essay

Background: Pathologic fractures of the mandible following radiation and embolization can be a challenging problem for patients. Occasionally, patients have already completed the oncologic component of their treatment and are trying to move on with their lives. A pathologic fracture is not only painful, but also a frustrating hindrance as it limits food intake and overall nutrition. In addition, pathologic fractures are challenging to repair.

of pathologic fractures of the mandible from osteoradionecrosis varies on age and overall medical health of the patient [4,8].
In the young healthy patient, adequate treatment can include resection of the osteoradionecrosis segment and replacing it with a vascularized bone graft. This requires additional surgery and often a gastrostomy tube and tracheostomy to protect the repair and for safety.
When head & neck, and plastic & reconstructive surgeons are in practice early on, they are presented with many diffi cult cases. This reconstruction is particularly complicated as it is important to retain the functional teeth, maintain the patient's occlusion, and construct a fi bula fl ap that is small enough to be inset to fi ll the resulting defect of the resection. While larger tumors or resections require larger bone grafts, the smaller segments of bone are removed to retain functional teeth. Given the rarity of pathologic fractures and their treatment, it is hard to fi nd a solution to approach this scenario in a textbook; and operating without planning can lead to the pitfall of postoperative malocclusion. Repairing pathologic fractures in the radiated and embolized setting is not straightforward and should be accomplished carefully. The pathologic malocclusion fi rst requires establishing appropriate dental occlusion, followed by surgical resection, and fi nally, free vascularized tissue as the surrounding tissue is hostile to other methods. We present a step-by-step approach to this diffi cult problem so that Head & Neck or Plastic & Reconstructive surgeons can use it as a reference when trying to manage these surgical problems.

Methods
A photographic chart review was conducted on our patient who developed a pathologic fracture of the mandible after a prior history of successful tonsillar cancer treatment. The 65 year old male patient had preoperative embolization for an intra-oral bleed, successful tonsillar resection with clear margins, and then postoperative radiation therapy. During a subsequent dental procedure, over one year after radiation therapy, the patient developed a pathologic mandibular fracture with subsequent pain and malocclusion including a posterior open bite.
A panorex, as well as a pre-operative anatomic fi ne-cut CT-scan of the face/mandible, was obtained. The estimated bone resection of the pathologic fracture was 4 cm. Given the previous embolization and radiation therapy, vascularized fi bula was selected for autologous reconstruction. Dental models of the maxillary and mandibular teeth were obtained from the patient's dentist to better understand the occlusal alignment. Synthes intra-operative models and occlusal splints were created to facilitate occlusal alignment. Photographs obtained intra-operatively as well as photos of the preoperative plan were used to develop a step-by-step approach for head & neck and plastic & reconstructive surgeons to use as a surgical fl ight plan.
Adjunctive treatments include G-tube placement for nutrition while awaiting intraoral wound closure, hyperbaric oxygen therapy for facilitating healing in the radiated bed, and Head & Neck occupational therapy for relieving jaw stiff ness.

Results
The appropriate medical clearance was achieved. The patient was taken to the operating room, and the surgical fl ight plan created was followed with photographs of the representative steps of the operation (Figures 1-16).

Discussion
Pathologic fractures of the mandible occur infrequently, and the surgical management will depend on the etiology of the fracture and the patient. The treatment of these fractures and their repair are technically challenging but rewarding for the operating team and the patient. In our patient, the malocclusion and the pain were the operative indications for surgical resection and reconstruction. In the re-operative patient, we have found  that taking necessary precautions in all steps of the planning is helpful to maximize outcome. Often in the re-operative and frustrated patient, there is an overtone of trying to appease the patient and not cause further inconvenience. In our experience, it is important not to omit any standard pre-operative or operative steps to placate the patient despite their frustration.
Reiterating to the patient that measures such as gastrostomy tube, tracheostomy, etc. are needed for safety will help the reoperative patient to understand. It is important to reiterate the success of their cancer treatment.
The impetus for this article was to create a step-by-step approach to mandibular resection and reconstruction in the  While these models help angle of osteotomy, they do not establish or set occlusion. Occlusion will need to be established prior to osteotomy in the operating room. This is an important part of planning. Intra-operatively, all steps were taken to ensure patient safety in the post-operative period in the intensive care unit.

Figure 4:
Step 1. General endotracheal anesthesia was undertaken. The endotracheal tube was converted into a tracheostomy for airway protection and swelling post-operatively and to facilitate anesthetic delivery in case of a return trip to the operating room for fl ap or bleeding emergencies.

Figure 5:
Step 2. Place arch bars. Prior to the surgical fi eld prep, the arch bars were placed with the intention to establish occlusion and maintain post-operatively in gliding elastics. The arch bars are the key to occlusal alignment. Pathologic fracture treatment is different than a primary resection where a patient has normal occlusion pre-operatively.

Figure 6:
Step 3. Expose the mandibular fracture. This is an important step. Wide exposure of the fracture was undertaken intra-orally and extra-orally for resection and irrigation of the osteoradionecrosis. The wide exposure allows easy mobilization of the mandible to re-establish occlusion.

Figure 7:
Step 4. Expose the recipient vessels. In patients with prior embolization or head and neck surgery preoperative ultrasound is helpful. The external jugular vein and facial vein were exposed to have dual venous drainage. The facial artery was exposed, however, contained a coil from previous embolization and was unusable. Proximal dissection was required to access the superior thyroid artery. Pre-operative ultrasound is helpful in previously radiated and embolized settings for surgical planning. pathologic fracture reconstruction is that the occlusion is not normal to begin with. Unlike a traditional resection and reconstruction, the occlusion is often normal or normal enough to be maintained. In our patient it was important to fi rst to recreate and mobilize the fracture and re-establish occlusion before embarking on resection and reconstruction.
In the patient who had previous embolization and previous surgery and radiation, we fi nd that a pre-operative ultrasound of the neck to look for arterial and venous recipient vessels is helpful. The vascular ultrasound can not only detect fl ow, Figure 8: Step 5. Recreate the mandibular fracture and mobilize the mandible. The pathologic fracture is easily identifi ed with a fi brous non-union after wide exposure. Osteotomy through the fi brous non-union allows the mandibular segments to move, to help re-establish occlusion.

Figure 9:
Step 6. Re-establish the occlusion of the teeth intra-operatively. Take your time with this step and make sure the teeth align properly from all angles. Dental models are extremely helpful. Make sure the condyle swings. This is an important step prior to pre-plate placement as this will help to set the fi nal post-operative occlusion.

Figure 10:
Step 7. Using the dental wires, bring the patient into appropriate maxillomandibular fi xation.  Step 9. Resect the pathologic fracture site back to a healthy bleeding bone edge. In this case, the object was to preserve all functional teeth as long as there was no osteomyelitic bone or necrotic bone. This is different than the patient with a malignant tumor of bone. Keeping the plate in place facilitates the oscillating saw. Removal of the plate then facilitated the fi nal osteotomy. The plate is returned to the mandible at the location where the holes were pre-drilled.

Figure 13:
Step 10 Harvest the Fibula Flap. After making the anterior skin incision, use the back end of the scalpel to bluntly dissect posteriorly to identify the perforator. Once the perforator is identifi ed, the peroneus longus and brevis can be retracted anteriorly and will make the dissection easier. Make the distal osteotomy and then proximal osteotomy in usual fashion.

Figure 14:
Step 11. Contour the fi bula fl ap. This could be accomplished with a ruler or tongue depressor as a model or the 3-D CT scan model. Grasping the fi bula with Kocher clamps are helpful for stabilization during the osteotomy. The resulting defect that was created was 3cm. The osteotomies were completed, and the fi bula fl ap was brought to the mandibular defect.

Figure 15:
Step 13. Stabilize the fi bula fl ap with screw fi xation to the mandibular reconstruction plate. Once stabilized, perform the microvascular anastomosis. The fi bula skin is deepithelialized leaving a small skin paddle to monitor with doppler and examine fl ap color. Inset the fl ap and close the neck wound.

Conclusion
Head & neck reconstruction is a challenging and humbling fi eld of surgery, but nonetheless rewarding. This surgical case encompasses many diff erent surgical principles, the most important are surgical planning and safety. In early stages of one's career, it is helpful to maintain a photo journal of maneuvers performed. This can help for future cases the surgeon encounters and serve as a measure for improvement in outcomes, effi ciency, and to minimize complications.