Treatment of mandibular discontinuity defects is a great clinical challenge.1–3 Partial or complete mandibulectomy is the surgical treatment of choice for patients diagnosed with malignant oral lesions involving the mandible.
The use of microvascular grafts to minimize the impairment of function, speech, and esthetics is the mainstay of modern surgical approach of the reconstructive team.
Advances in microvascular surgery have provided the surgeon with methods to repair the partially resected mandible with vital bone grafts. Vascularized bone is used for the secondary reconstructions with large defect, where soft tissue is inadequate, or where the recipient bed has been compromised by radiation, chronic infection, or previous surgery. Often, however, reconstruction of the bony defect alone does not guarantee an adequate foundation for successful conventional prosthetic rehabilitation. Osseointegrated implants placed into the microvascularized grafted bone offer an opportunity for improved function and patient satisfaction and have become the preferred treatment modality.4–6
A variety of donor sites have been used for this purpose, including the iliac crest, radius, scapula, and fibula.7–10 However, currently the microvascular free fibula flap represents a versatile reconstruction method after mandibularablation.3
The free fibular microvascular flap was one of the earliest osseous free flaps with successful application in large bony defects.11–14 Hidalgo was the first to report the use of a fibula vascularized flap for mandibular reconstruction with 100% osseous survival in a series of 13 patients.15
Some of the documented advantages of using free fibular microvascular flaps are
The quality of fibular bone transfer and its rich periosteal blood supply makes it very safe and useful for mandibular reconstruction. The nature of the fibular blood supply allows precise graft shaping by multiple osteotomies using a prefabricated template.
It allows mandibular reconstruction without transferring a large bulk of soft tissue as is required in the iliac crest vascularized flap.
In addition, the fibula provides adequate amount of bone width and height to support osseointegrated implants that support the functional reconstruction via overdenture or fixed reconstruction.2
In recent years many reports of jaw reconstruction using free vascularized flaps have been published. However, the literature does not report any total reconstruction of the mandible using a vascularized free fibula graft followed by prosthetic rehabilitation. There are a number of unique clinical problems encountered during such prosthetic rehabilitation. The authors have encountered these problems during the jaw relation registration and the overdenture trial stage.
The following case report presents the prosthetic rehabilitation of a totally mandible reconstructed with a vascular free fibular graft using an implant-supported overdenture.
A 24-year-old female patient reported to the Department of Oral and Maxillofacial Surgery with a history of mandibular nerve neuroma treated with mandibular resection followed by reconstruction with a fibular graft about 3 years ago. Radiographic examination revealed a failed reconstruction (Figure 1).
The patient had no systemic disease and all routine investigations were normal.
Planning of the prosthodontic rehabilitation prior to mandibular reconstruction has been suggested as playing a vital role for a successful dental reconstruction.4
The case was planned for resection of the failed fibular flap followed by simultaneous reconstruction with a free fibular vascularized osteocutaneous flap.
Since the mandibular reconstruction was performed secondarily (ie, following failure of a previous reconstruction), the contours were established using normal maxillo-mandibular relationships. A wax rim supported by a record base was utilized as a stent in order to establish the contours of the reconstructed fibula.
Once the contour and length were established, the graft was then fashioned into the shape of the mandible by judiciously placed osteotomies and bone wedge resection; care was taken to meticulously preserve the periosteum. The osteotomies were performed sequentially and were maintained in position with a titanium miniplate system (2-mm 4-hole plate with gap and 2- by 10-mm screws; Orthomax, India; Figure 2).
The reconstructed fibula was then oriented in place of the mandible and anastomoses with vessels was done.
The panoramic radiograph showed well integrated fibula flap after 6 months (Figure 3).
Implant placement was planned in the reconstructed area.
After adequate healing for about 8 months from the initial reconstructive surgery, dental implants were inserted secondarily to allow a more accurate implant positioning according to the prosthodontic needs. Care was taken during incision, flap elevation, and implant site preparation to avoid damaging the vascular pedicle of the fibula flap.
Four implants were placed into the reconstructed mandible under local anesthesia (3 implants, Uniti D5.3 × L10 and 1 Uniti D4.3 × L10; Equinox, Medical Technologies, BV, Ziest, Holland). Primary stability of all implants achieved was achieved and verified by Periotest (Medizintechnik Gulden eK, Modataul, Germany). All implants were allowed to integrate for a period of 4 months before second-stage surgery. The healing period was asymptomatic.
After 4 months, second-stage surgery for implant exposure was performed along with skin graft harvested from the medial aspect of the thigh. An acrylic stent relined with tissue conditioner was used to stabilize the tissues using titanium bone plating screws (1.5 × 6 mm; Orthomax, India).1
However this graft failed to take up due to a postoperative infection and an additional vestibuloplasty was performed to allow increase in attached gingiva to provide an adequate amount of keratinized mucosa around the implants so as to allow maintenance procedures.
After adequate healing of the site the implants were uncovered and an acrylic stent was fabricated to maintain the patency of the emergence profile of the gingival formers.
Straight abutments (Uniti D5.3; Equinox Medical Technologies) were placed into the terminal implants while gingival formers were placed on the implants closer to the midline. Addition silicone putty (Affinis Putty super soft, Coltène Whaledent, Langenau, Germany) was manipulated and adapted over the straight abutments. It was then molded to fabricate an index. The index so formed was then flasked and packed in clear self-cure acrylic resin. (DPI, India) The acrylic resin stent was stabilized intraorally by cementing the stent using GIC luting agent (GC Fuji I glass ionomer luting cement, GC America, Alsip, Ill) onto the straight abutments. (Uniti straight abutments D5.3, Equinox Medical Technologies) The stent was placed to hold the labial tissues away from the implant abutments and to maintain patency of the exposed implants (Figure 4).
After a month the patient was recalled and the stent removed. The central implants were re-exposed. Preliminary impression was made using a stock tray and modeling plastic impression compound (Y-Dents impression compound, MDM Corporation, New Delhi, India) and poured in dental stone. Open tray impression posts were placed and final impression made using Impregum Penta medium body polyether (3M ESPE AG, Seefeld, Germany; Figure 5).
Due to the thickness of overlying soft tissue, a closed-tray impression coping could not be utilized. The angulation of the medial right implant, and its proximity to its neighboring implant, precluded the utilization of long open-tray impression copings. Hence it was decided to utilize only 3 implants for the prosthetic rehabilitation. Laboratory analogues were attached and the impression was poured to obtain the working model.
The orientation of the implants was verified intraorally using a transfer orientation jig fabricated on the master cast (Figure 6).
Considering the amount of the excessive overlying soft tissue, to obtain maximum stability of the record base during recording of jaw relations, the record base was then fabricated over the jig.
It was observed that the amount of closure of the reconstructed mandible was dependent on the position and tilt of the head. Thus the horizontal and vertical jaw relations varied with the amount of opening. This could be attributed to the pseudo TMJ reconstruction and lack of direct muscle attachments with the reconstructed mandible. Hence it was decided to record the jaw relation record with the head tilt (centered) with a straight gaze as that was the position the patient would assume during mastication and at rest. This facilitated development of maximum intercuspation at the particular head tilt and allowed maximum masticatory efficiency (functional efficiency) thus allowing better patient satisfaction and improving quality of life (Figure 7).
Tentative maxillo-mandibular relationship records and diagnostic arrangement of teeth were made to evaluate the amount of space for prosthetic platform fabrication. Other parameters like occlusion, esthetics, and phonetics were also evaluated.
It was decided to splint all 3 implants with a platform to harbor the precision attachment (Ball and O-ring) for retention of the prosthesis.
Using waxable bridge abutments a prosthetic platform was fabricated in pattern resin (GC America) to splint the implants. After verifying the fit of the platform intraorally the precision attachments (ball attachments from OT cap system, castable single spheres [Rhein 83 attachments, Bologna, Italy]) were attached on top of the platform and it was cast in nickel-chromium alloy (Hi-Chrom Soft-7, High Dental Japan, Osaka, Japan; Figure 8).
The passive fit of the framework was evaluated using radiographs. A record base was fabricated over the framework with the O-rings incorporated in order to stabilize the base; jaw relation records were made.
Anatomic teeth were selected for maximum masticatory efficiency to compensate for decreased muscle action due to lack of direct muscle attachments. A shortened dental arch concept was utilized to reduce the amount of cantilever and decrease the amount of stress on the implants. The second premolar tooth was omitted and replaced by a second molar. This was done to increase the surface area of the occlusal table to improve the masticatory efficiency and compensate for the lack of normal masticatory muscle attachments (Figure 9).
The try-in denture was evaluated for esthetics, phonetics, and occlusion. The try-in denture was then processed using injection molding technique. (BPS-Biofunctional Prosthetic System, Ivoclar Vivadent, Liechtenstein; Figures 10 through 12).
At the time of prosthesis delivery, a panoramic radiograph was taken to check implant position and the coupling between prosthetic components (Figure 13).
The patient was instructed to eat a soft diet during the healing period of 3 months. Oral hygiene instructions, including the use of toothbrushes, interdental brushes, Waterpik (Water Pik Inc, Fort Collins, Colo) and chlorhexidine mouth rinse were given.
The literature also reports an excellent potential prognosis for implant-supported prostheses with the long-term survival and success rates of implants placed in reconstructed jaws ranging from 86–99%.4,16–20 Hidalgo and coworkers have reported a success rate of 100% for a series of 19 patients over a 10-year followup.16 Kramer reported a success rate of 96.1% after an observation period of 1400 days.17 Wu reported that high primary stability for implants placed into the free fibula grafts was achieved. The 1-year and 5-year cumulative survival rates of the implants were 96% and 91%.18
The implant-supported fixed restoration is often considered the treatment of choice for patients following jaw resection/reconstruction.17 However, its fabrication requires more implants, and the initial treatment cost is much higher than the implant overdenture option.18,21 The lack of keratinized mucosa, coupled with reduced labial sulcus depth and limited oral access hinders the patient's oral hygiene procedures. Removable implant-supported prostheses are easier for the patient to clean.22,23
Hence an implant-supported removable prosthesis was planned for the patient. The implants were splinted to minimize movement of the prosthesis during function and better distribution of forces.
Over a period of 2 years the patient reported great comfort and ability to function with the prosthetic reconstruction. The patient was able to wear the prosthesis easily. The patient reported ability to eat most of the normal to near normal diet except for nuts, meats. The level of retention achieved from the attachments helped in psychological comfort which in turn had positive impact on the patient's confidence levels. During the followup time period the plastic attachments had to be replaced once due to routine wear and tear. Although, following surgical failure of the first fibular graft, the fibula from other leg was utilized for the secondary reconstruction. The patient did not report or display any significant donor site disability that had effect on or would curtail any form of routine physical activity.
The reconstructed mandible acted as a stable platform for tongue mobility. Thus the patient showed excellent speech quality postoperatively. Postoperatively, there was significant change in the patient's profile, facial proportions and symmetry (Figure 14). Over a 2-year followup period, there was no detectable distortion to the outcome achieved. Radiographically the grafted bone did not show any significant change and was uniformly stable. These outcomes had a significant effect from a quality of life standpoint.
In conclusion, the fibula free vascularized flap is a safe and reliable method for comprehensive functional and esthetic mandibular defect reconstruction. The use of the free fibular vascular flap of the second leg following failure of the first flap led to an excellent surgical and prosthetic outcome. The protocol followed for the case had a significant impact on enhancing the patient's quality of life.
The authors report no sources of support and no conflicting interests for this paper.