Reconstruction of Mandible with Free Fibula Flap:Report of Three Cases

Introduction

Segmental resections of mandible frequently cause severe facial defects which results in difficulty in chewing, seriously affecting the standard of life. Malignant and benign tumors, as well as infectious diseases or trauma can result in segmental defects of the mandible.1 The interruption of the mandibular continuity, muscular detachments and loss of motor and sensory innervations leads to difficulty in mastication, swallowing and speech. Immediate reconstruction is preferred from a functional and aesthetic point of view.^1,2 Iliac crest free flap, radial forearm flap and scapula osteocutaneous flap are the other techniques used in reconstruction of mandible. Hidalgo popularized free fibula flap in mandibular reconstruction which was introduced by Taylor and colleagues, due to its favourable characteristics like vascular pedicle and diameter of the vessel, length of the bone which affords to carry out multiple osteotomies to contour the transplanted segment.^3,4 The fibula free flap has high success rate with minimal donor site morbidity making it an excellent choice for mandibular reconstructions, independent of the cause of the bony defect.^3,4

The transplanted bone segment provides adequate width and height to allow for the placement of osseointegrated dental implants for oral rehabilitation.⁵ We present three cases of segmental mandibular defects reconstructed primarily with vascularised free fibular flap without skin paddle which were followed up for two years without any complications.

Case report

Case 01:

A 16-year-old female presented with a swelling on the right side of the face from past one year (Figure 1). Examination of the region revealed a smooth bonyhard swelling involving right angle and body region of the mandible obliterating the right gingivo-buccal sulcus. OPG and CT scan (Figure 2) revealed a radiodense mass with small multicystic radiolucencies involving right angle and body of the mandible causing facial asymmetry with expansion of involved bones. An incisional biopsy was subsequently performed, providing a diagnosis of ossifying fibroma. Based on the clinical history, radiographic and histopathological features of the lesion, a diagnosis of aggressive ossifying fibroma was established. The patient was planned for surgery under general anesthesia for segmental resection of mandible with primary reconstruction using free fibula flap (Figure 3 and Figure 4). The patient was followed up for two years with satisfactory facial profile and intraoral healing with no complications at donor and recipient sites (Figure 5 and Figure 6).

Case 02:

A 26-year-old male patient presented with a history of swelling in right lower jaw region since eight months. On examination, significant swelling was present on the right body and parasymphysis region of mandible which was non-tender with normal overlying skin (Figure 7). Correlating with the history and clinical examination, panoramic radiograph was advised which revealed a well-defined, large expansive multilocular radiolucency in the right mandible extending from the midline to anterior border of ramus on the same side with resorption of involved teeth (Figure 8). Incisional biopsy was made intraorally in the right vestibular region which revealed follicular ameloblastoma and subsequently patient was posted for surgical resection with primary reconstruction using free fibula flap (Figure 9). The patient was followed up for two years with satisfactory facial profile and intraoral healing with no complications at donor and recipient sites (Figure 10 and Figure 11).

Case 03:

A 60-year-old female patient presented with a history of swelling in left lower jaw region since six months (Figure 12). On examination, significant swelling was present on the left body region of mandible which was non-tender, with ulcerated overlying mucosa in the lower buccal sulcus. The panoramic radiograph revealed a well-defined, mixed, radiolucent-radiopaque lesion involving left body of the mandible (Figure 13). Incisional biopsy was made and the lesion was diagnosed as squamous cell carcinoma. The treatment plan was radical neck dissection with segmental resection of mandible involving wide margins to avoid recurrence followed by primary reconstruction using free fibula flap (Figure 14). The patient was followed up for two years with satisfactory facial profile and intraoral healing with no complications at donor and recipient sites (Figure 15 and Figure 16).

Surgical Procedure

All three patients were operated under general anesthesia involving two surgical teams to reduce the operating time; one team resected the lesion and the other team simultaneously harvested the free fibula flap. Erich arch bars were placed preoperatively for both maxillary and mandibular arches except for the segment to be resected. Risdon’s incision was used to expose the lesion in two cases except in one case where radical neck dissection was carried out, and the tumour was exposed subperiosteally and resected with 1 cm margin on either side using Gigli saw. The facial artery and the vein were isolated and vascular clips for future vascular placed for anastomosis.

On the donor site, the other team simultaneously exposed the fibula using lateral surgical approach. The patient’s knee flexed at 90° and the pelvic girdle was internally rotated with a roll placed under the ipsilateral hip with tourniquet applied around the thigh without exanguination. Surgical markings were made from the fibular head to the lateral malleolus indicating the submascular and subcutenous course of fibula. Around 6 cm of proximal bone was preserved to avoid injury to the peroneal nerve and distally 8 cm of bone was left to support the ankle. The peroneus longus was anteriorly reflected, and the fibular bone was identified and the posterior crural septum was located and examined for perforators. Extensor hallucis longus was transected after thick interosseous septum was identified, posterior dissection was performed. Osteotomy cuts were made with Gigli saw and the bone was retracted laterally and the interosseous membrane was transected. The tibilis posterior was dissected and the pedicle underneath was identified and ligated and the flexor hallucis longus and soleus muscles were transected. Dissection was continued till the posterior tibial bifurcation and the anterior and posterior tibial pulses were palpated prior to transecting the peroneal vessels. The bone length required for reconstruction was measured with K wire and osteotomy was performed, and the leg wound was closed primarily. The harvested bone was adapted, pre plated and fixed to the residual mandibular defect using stainless miniplates using 8 mm screws. The pedicle was positioned along the lingual aspect of the flap. The anastomosis was then performed with standard micro vascular techniques using microscope/surgical loupe, first facial vein then facial artery was anastomosed preferably.

Adequate measures were taken to avoid complications at donor and recipient sites. Drains were used in the limbs until output was minimal for removal. Compartment syndrome was prevented by avoiding over tight closure of the limbs using drains to avoid hematoma. The recipient site was closely monitored for early identification of any vascular compromise. A regular monthly follow up was advised for a period of two years to detect any donor site or recipient site morbidities and removable partial denture was placed to aid in mastication.

Discussion

Mandibular reconstruction after segmental resection is a complex procedure causing residual defect on the oromandibular function, aesthetics and quality of life. The most common indication for mandibular reconstruction remains ablative surgery for benign and malignant tumours of the oral cavity and oropharynx.

With the present technical and surgical advancements, reconstruction of mandibular defects has become a highly standardized procedure over the past decade. When Hidalgo introduced free fibula flap for reconstruction of mandible, it became a gold standard reconstructive technique in maxillofacial surgery.^4,5 Several factors like availability of surgical expertise, equipment, medical fitness, financial factors affect the choice of reconstruction. Fibula with its tubular structure similar to mandible, with the presence of endosteal blood supply and dense cortical plates helps for carrying out multiple osteotomies without compromising blood supply. The availability of 20–25 cm of bone for harvest and minimal donor site morbidity makes it an ideal choice for mandibular reconstruction.⁶ As fibula is not the prime weight bearing bone, its removal will not affect the function of the leg. Since the fibula is distant from recipient site, the resection and reconstruction operating teams can work simultaneously. Although Hidalgo mentioned that the blood supply for the cutaneous flap is not good in his first report, the peroneal artery perforators for cutaneous flap perfusion are sufficient to achieve anastomosis.^5,6

Height of the fibular bone is the only disadvantage at the anterior segment. To improve the aesthetic and functional outcome, double barreling of the fibula is done to create equal struts.^6,7 Immediate osseointegrated dental implantion in double barreled fibula gives good results and fewer complications.⁷ Intermaxillary fixation plays an important role to maximize the precision of the reconstruction. Intermaxillary fixation screws and Erich arch bars are most commonly used techniques where more stability is needed.⁸ The timing of reconstruction largely is very important as some surgeons prefer secondary reconstruction as secondary surgeries give ample time for adequate healing of the tissues and in the event of recurrence, the critical tissue resources for the reconstruction, as well as financial resources, are lost.^9,10,11Despite these advantages of secondary reconstruction, primary reconstruction is preferred because of its surgical, functional, and psychological advantages.¹² Primary reconstruction after radical excision has several advantages to secondary reconstruction like lower morbidity rate, preventing soft tissue fibrosis and obliteration of recipient vessels, secondary surgical procedure and economic burden.^13,14,15

Conclusion

The free fibula flap is a versatile and reliable choice for the reconstruction of large segmental mandibular defects. It provides a large quantity of bone, which could easily be shaped and adapted to the remaining mandible, with good length of vascular pedicle which can be easily harvested for anastomosis. It is indicated for young patients with need of dental implants for oral rehabilitation as it has good osseointegration. The free vascularised fibula flap has the advantage of two teams working simultaneously which reduces operating time, thereby reducing blood loss and lower incidence of infection. The donor site morbidity of the free vascularized fibula graft is consistently acceptable and is avoidable with meticulous planning and appropriate surgical technique. With our experience, the free fibula flap can be the primary choice for the majority of mandibular defect reconstruction cases.

Conflict of Interest

None.