Fibula Free Flap Reconstruction of the Maxilla Leading to Extracapsular Ankylosis of the Mandible

After en bloc resection of the maxilla or mandible, surgeons may choose to replace the missing bone and soft tissue with a fibula free flap (FFF). One of the complications that may arise during the healing of an FFF is heterotopic ossification along the free flap pedicle. Heterotopic ossification is most often noted incidentally on postoperative radiographs and rarely creates a functional deficit. Subperiosteal dissection of the pedicle from the bone during the harvest of the FFF is believed to be the main contributing factor that leads to this formation of bone along the flap soft tissue. Pain or limitation of movement of the jaws, depending on where heterotopic bone forms, are related functional issues. Changes in facial appearance due to expansion related to this phenomenon of bone deposition may also occur. This paper presents a patient that developed a functional deficit secondary to heterotopic ossification of an FFF that required surgical intervention. The goal of our surgery is to maintain the blood supply to a vascularized flap while removing the heterotopic bone. We will present the unique aspects of planning this challenging surgery: A 40-year-old man with a history of right posterior maxillary ameloblastoma underwent a hemi-maxillectomy with FFF reconstruction. The patient developed extracapsular heterotopic bone ankylosis beginning 2 months postoperatively developing severe trismus and required surgical intervention. Radiographic imaging revealed extensive heterotopic ossification of the vascular pedicle that extended from the most proximal positioned end of the fibula to the inferior lateral border of the mandible. A radiographic computed tomography with contrast imaging revealed an intact vascular pedicle with surrounding heterotopic bone. Virtual planning and stereolithic modeling were utilized to plan the heterotopic bone removal. In the operating room, we removed the heterotopic bone in small segments according to the virtual plan to avoid injuring the vascular pedicle. A coronoidectomy was also performed to help gain more range of motion. An adipofascial flap using the buccal fat pad was raised into the area of defect to prevent future recurrence. The patient was put on a strict physical therapy regimen to help regain his range of motion. Heterotopic ossifications along free flap pedicles are a known complication of the FFF. A conservative management approach should be used since most postoperative patients will be asymptomatic and findings are incidental on postoperative imaging. Surgery should be reserved for symptomatic patients. Heterotopic ossification needs to be considered as a differential in a microvascular reconstruction postoperative patient when the patient presents with a slow onset of facial swelling, neck mass, or trismus. Virtual planning is an essential tool in the surgeon's planning armamentarium dependent on the timing of the procedure so that the vascular integrity of the flap can be protected after the initial anastomosis.