Tumor resection in the maxilla or in the mandible can lead to significant facial deformity, altered oral functions, and subsequent psychological problems. Rehabilitation of patients with orofacial defects after tumor resection poses a common and challenging problem in maxillofacial surgery.1,2 The regeneration of bony defects of the jaws using free vascularized tissue grafts has become a reliable procedure during the last few years. Various donor sites are available to provide vascularized bone grafts for mandibular or maxillary reconstruction such as the fibula flap, the iliac flap, the rib flap and the scapula flap. Vascularized grafts provide a good bulk of bone in which to place implants and a satisfactory contour. Among these alternatives, the fibula-free flap presents many advantages compared with the scapula or the iliac crest. It was demonstrated that the fibula flap offers favorable conditions for implant placement due to its strong bicortical bone. Dental implants contribute significantly to the restoration of adequate function over other tooth-replacement options, because implant-supported prostheses are far more stable.2–7 The purpose of this study was to evaluate the clinical status and success rates of dental implants inserted in fibula-free flaps used for orofacial reconstruction following ablative tumor surgery.
Between December 2000 and December 2005, 29 consecutive patients were investigated and used for the present study. They underwent orofacial reconstruction with an autogenous fibula-free flap and received dental implants. The patients were selected from a large cohort of patients undergoing surgery for oral and maxillofacial resections in one single unit. Only a small group of patients were selected and could afford oral rehabilitation with implants, some were selected for conventional prosthodontics, and others received no further treatment. Patient selection criteria for implant treatment were as follows: favorable relationship between the mandible and the maxilla; reasonable tumor prognosis based on stage and grade for cancer patients; good residual tongue function; absence of systemic diseases; good oral hygiene and realistic expectations. Twenty-one patients were male and eight were female. The average patient age at the time of implant placement was 47.1 years with a maximum of 61 years and a minimum of 26 years. Thirteen patients suffered from defects caused by destructive malignant tumors (6 in the maxilla, 7 in the mandible), 7 patients had benign tumors of the mandible, and 1 patient presented with benign tumors of the maxilla. Eleven of the 29 patients were completely edentulous while all other patients were partially edentulous. Three patients received radiotherapy of the head and neck area with irradiation doses ranging from 40 to 65 Gy before implant placement. All procedures were performed in the same hospital and by the same surgical team.
In 15 patients, the fibula-free flap was used as an osseofasciocutaneous flap; and in 14 patients it was used without the cutaneous component. In 27 patients, reconstruction with a fibula-free flap was performed immediately after mandibular or maxillary resection (primary reconstruction). Only 2 patients were reconstructed some time after the ablative procedure (secondary reconstruction). Twenty-two patients received a conventional monobarred fibula graft. The fibula flap was shaped in 2 patients as a double-bar. In 1 patient, additional free bone grafting, using corticocancellous iliac grafts, was performed. In 4 patients, the insufficient height of the fibula transplant was successfully corrected by means of vertical distraction osteogenesis with a dental implant distractor (DID) distraction device (China).7
Implant placement and prosthodontic treatment
Two implant systems were used: Brånemark (Nobel Biocare, Gothenburg, Sweden) and ITI (Straumann, Basel, Switzerland). A total of 117 implants were placed, i.e., 66 ITI, 51 Brånemark. The implants were placed by 2 doctors from the Department of Oral and Craniomaxillofacial Implant. Dental implants were immediately placed in 19 patients at the time of reconstructive surgery (Figure 1). Defects may result from resection of benign tumors or low-grade malignancies. Implants were placed in 10 patients using a 2-stage procedure after adequate healing from the initial reconstructive surgery. The diameter of the implants placed varied from 3.3 mm to 5 mm; the length varied from 10 mm to 20 mm. All implants were allowed to integrate for at least 3 months before stage-2 surgery. Prosthodontic restoration was accomplished by the same 2 doctors who placed the implants after stage-2 surgery and completed healing of the soft tissues. Evaluation included assessment of implant survival, mucositis, and peri-implantitis. Measurements of bone level changes were evaluated mesially and distally to each implant. We measured the vertical distance from the neck of the implant to the crest of the surrounding bone tissue to evaluate peri-implant bone loss. According to Albrektsson,8 the criteria for successful implants are: absence of persistent pain; absence of peri-implant infection with suppuration; absence of mobility; absence of continuous peri-implant radiolucency; peri-implant bone resorption less than 1.5 mm in the first year of function and less than 0.2 mm in the subsequent years. Implants still functioning with no mobility, pain or infection, but with peri-implant bone resorption more than 2 mm, were classified as survival implants. Implant failure was defined as implant removal. We analyzed the causes of implant loss, peri-implant bone resorption and the etiology of soft tissue proliferation.
Implant survival rates and success rates were estimated with the cumulative Kaplan-Meier method and compared using the chi-square test. All statistical analyses were made using statistical software (SPSS 11.0 for Windows, SPSS, USA). There were no significant differences between pairs of implant system groups. A P value of less than 0.05 was considered statistically significant.
The mean follow-up period after implant placement was 47.8 months (range, 24–84 months). The cumulative survival rate of the fibula bone grafts was 100%. Only one flap underwent necrosis of the skin paddle, but did not present problems to the bone graft. Nine implants were lost (6 international team for implantology (ITI) and 3 Brånemark) during this investigation; they were placed in the fibula bone. One implant placed in the native jaw was lost (Brånemark). All the failure implants were found before the prosthetic procedure. None of the implants that inserted in patients who received radiation were lost. Only 3 patients received radiotherapy in our series. With regard to implant distribution, 29 implants were placed in the maxilla and 88 were placed in the mandible. Seventeen implants were placed in the native jaw. One hundred implants were placed in a fibula bone flap. The most commonly used implant dimensions were 4.1 mm × 10 mm, 4.1 mm × 12 mm, 3.75 mm × 10 mm, and 3.75 mm × 13 mm. Thirty-seven implants had a machined surface and 80 had a rough surface. After fitting of the prostheses, the patients were placed on long-term review in the oral and craniomaxillofacial clinic, as well as the usual oncologic follow-up in the oral and maxillofacial clinic.
Peri-implant soft tissue proliferation is a common phenomenon for implants placed in a fibula-free flap (Table 1). In our study, 6 patients (17 implants) who had soft tissue hyperplasia needed surgical removal. Oral hygiene should be well maintained in these patients. Routine visits are necessary for the early detection of inflammation, infection or bone resorption.
At the time of follow-up, 28 patients had functioning dentures. Of these, 21 had fixed bridges retained by dental implants (15 hybrid and 6 metal ceramic prostheses), 4 had bar-supported overdentures on dental implants and 3 had O-ring-retained overdentures (Figure 2). These prostheses were retained by 104 functioning implants (Table 2). The other 3 implants were not integrated into the prosthodontic treatment (implants without function). The analysis of the 3 sleepers showed that 1 implant was never loaded and that the underlying reasons for the other 2 implants were persistent soft tissue hyperplasia.
Implant survival rates and success rates were calculated using the cumulative Kaplan-Meier method. The 1-year and 5-year cumulative survival rates of the implants placed in the fibula bone grafts were 96% and 91%, respectively. Because of unfavorable local soft tissue locations in 2 patients, 3 implants had to remain unexposed as “sleepers”. Another 2 implants had peri-implant bone resorption more than 2 mm. Therefore, the 1-year and 5-year cumulative success rates of the implants placed in the fibula bone grafts were 95% and 87%, respectively.
Most patients with jaw reconstruction after tumor ablation were satisfied with bone and soft-tissue restoration. All patients were able to use the dental prosthesis for chewing. Oral functions including chewing, swallowing and speaking were improved, and the patients were satisfied with the cosmetic results. Our study showed that implant-supported dental prosthetic rehabilitation always positively influence oral function.
Microsurgical techniques are now considered safe and reliable for jaw reconstruction. The reconstruction of maxillo-mandibular continuity defects caused by tumor surgery often requires a free vascularized tissue transplant. Free revascularized flaps have become a valuable means for the rehabilitation of such patients.1–4 Different donor sites such as the iliac crest, the fibula, the scapula, and the radius have been recently suggested for use. These flaps allow for the immediate reconstruction of defects despite unfavorable local conditions such as large defects and irradiation. The iliac osteocutaneous free flap can provide sufficient bone for jaw reconstruction and the insertion of osseointegrated implants. The radial forearm osteocutaneous flap and the scapular osteocutaneous free flap have also been used for jaw reconstruction, but they are not suitable for osseointegrated implants.4–6 Since its introduction in 1975, the fibula-free flap has become a routine procedure for the functional reconstruction of extended defects of both the mandible and the maxilla. The fibula flap has many advantages for jaw reconstruction compared with any other vascularized bone grafts. The flap can be easily shaped with osteotomies, according to the defect size. The pedicle of the fibula flap is always long and large enough for microanastomoses. Morbidity has been recorded to be acceptable in all previously treated patients.9–11
The purposes of oral rehabilitation include both esthetic and functional aspects. Patients who receive surgical ablation of oral tissues often lack of a functioning dentition, and are unable to wear conventional prostheses due to insufficient bone height or an unfavorable environment for tissue-bone prosthesis. In the last few years, dental implants have been proven to be a very reliable means for dental rehabilitation, not only in healthy edentulous patients but also in patients with sequelae of tumor surgery. Satisfactory functional results after implant rehabilitation of patients with reconstructed jaws have been published in a number of clinical studies.10–13 Therefore, for many patients, implant-supported prosthesis offers more effective rehabilitation than conventional dentures. In this investigation, implant-supported prosthetic rehabilitation used 4 principles of fixation. The application of dental implants has greatly contributed to the successful treatment of these patients. At the time of follow-up, 28 (96.55%) patients had functioning dentures.
Compared with healthy patients with conditions following tooth loss, patients with severe maxillo-mandibular defects offer more complicated surroundings for implants due to surgical alterations of the oral cavity. Factors contributing to the failure of dental implants include infection, heavy smoking, radiation therapy, bone quality, use of bone grafts and poor oral hygiene.14–16 Therefore, patient selection is important to avoid unfavorable results. Our high survival rates could be attributed to the high ratio of benign tumors in this study and the selection of implant candidates. The use of vascularized bone grafts may have contributed to the high rate of implant survival. However, in situations where there is massive soft tissue loss, functional outcomes can be poor even with implant-supported prostheses. In the present study, patients with large soft tissue defects would not be selected for implant treatment. Our study showed that implant-supported dental prosthetic rehabilitation always positively influences oral function. Soft tissue proliferation around the implant abutments is a common phenomenon of the reconstruction of intraoral soft tissues. Oral hygiene should be well maintained. Regular recall visits are a prerequisite for the long-term success of such treatment and for the early detection of inflammation, infection or bone resorption. Tissue movement, plaque accumulation, and ineffective oral hygiene efforts may affect peri-implant health and possibly long-term retention of the implant. In the present study, of the 13 patients who had soft tissue hyperplasia that needed surgical removal, only 1 patient developed implant failure.
The fibula flap presents many advantages but a limitation may be insufficient bone height (rarely more than 13 mm) for the reconstruction of the alveolar ridge. It presents some problems from a prosthetic point of view, particularly in cases of partial mandibular resection with residual dentition on the healthy side. The distance between the implant shoulder and the occlusal plane is large, leading to an unfavorable crown-to-implant ratio. This situation also creates a significant difference in the level of the alveolar crest between the residual mandible and the reconstructed part, therefore causing functional and esthetic problems. A solution to this problem may be the use of double-barrel fibula bone transfer to allow simultaneous reconstruction of the maxilla and mandible.17,18 In this series, the fibula flap was shaped in two patients as a double-bar. However, the length of the fibula bone segment may not be sufficient for the correction of a large defect. Another alternative may be the use of vertical distraction osteogenesis. This method has recently been applied for alveolar distraction in the case of severely resorbed edentulous jaws to improve bone volume for dental implant placement. 19,20 Using an external device7 (DID) that increases the alveolar height of the microvascularly transplanted fibula, vertical distraction osteogenesis was performed to enable prosthetic rehabilitation with dental implants. Four patients in this study underwent segmental vertical distraction of the fibula bone. The increase in vertical bone height was stable and enabled the placement of dental implants without any complications. The final result represents an improvement of the local anatomy, with functional and esthetic optimization of the implant-supported dental rehabilitation. Further research is necessary to evaluate the possible applications and limitations of this technique.
The results of the present study indicate that implants placed in vascularized fibula bone grafts are safe and reliable. We found that dental implants placed in composite fibula-free flaps performed approximately as well as those placed in regular bone. Despite some persistent soft tissue problems and implant loss, most patients demonstrated successful prosthetic and functional results.
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