|Year : 2017 | Volume
| Issue : 1 | Page : 33-38
Rehabilitation with dental implants after mandibular reconstruction with microvascular fibula flap with previous osteoradionecrosis
Rafael Martin-Graniz1, Diana Carolina Correa-Muñoz2
1 Department of Oral and Maxillofacial Surgery, Hospital Clínico San Carlos, Madrid, Spain
2 Department of Oral and Maxillofacial Surgery, Hospital Clínico San Carlos, Madrid, Spain; Department of Oral and Maxillofacial Surgery, Nacional University of Colombia, Bogotá, Colombia
|Date of Web Publication||13-Feb-2018|
Diana Carolina Correa-Muñoz
Calle 23 # 54-79 Medellin, Colombia
Source of Support: None, Conflict of Interest: None
| Abstract|| |
This article discusses how the microvascularized fibula flap with or without cutaneous component has become the reconstructive option of choice for mandibular defects due to its length,the ability to be molded, its acceptable and consistent vascular pedicle, and the relative ease to obtain. Since this bone has shown, due to its vascularization, to maintain the bone mass in time, which gives a potential advantage over other free bone flaps, and therefore, the possibility of rehabilitation with dental implants. However, this can be a challenge because most of these patients have large oncologic resections, frequent medical comorbidity, and often require associated radiotherapy. Initially we review some published works about changes over time in height and bone mass of fibula bone in patients treated for osteoradionecrosis (ORN), and therefore, about the success or failure of the implant rehabilitation in these patients was performed. After, the case of a male patient aged 40 is presented who underwent mandibular reconstruction with fibula free flap after an oncological resection which showed a picture of ORN managed with previous surgical therapy and hyperbaric oxygen as adjuvant therapy and on whom rehabilitation was then performed with implant-supported prostheses with favorable development during 7 years follow-up. Therefore we conclude that the microvascularized fibula bone can receive a functional dental rehabilitation with osseointegrated implants even if there has been a previous history of properly treated ORN.
Keywords: Fibula, microvascularized, osteoradionecrosis
|How to cite this article:|
Martin-Graniz R, Correa-Muñoz DC. Rehabilitation with dental implants after mandibular reconstruction with microvascular fibula flap with previous osteoradionecrosis. J Dent Implant 2017;7:33-8
|How to cite this URL:|
Martin-Graniz R, Correa-Muñoz DC. Rehabilitation with dental implants after mandibular reconstruction with microvascular fibula flap with previous osteoradionecrosis. J Dent Implant [serial online] 2017 [cited 2021 Nov 29];7:33-8. Available from: https://www.jdionline.org/text.asp?2017/7/1/33/225398
| Introduction|| |
Previous studies have suggested that radiotherapy does not affect the rates of local complications after reconstruction with microvascular free flap for head and neck cancer. However, there is little data that indicate whether the presence or absence of osteoradionecrosis (ORN) affects the outcome of the treatment. The mandibular ORN is potentially one of the most serious complications of radiotherapy in patients treated for cancer of the head and neck. Originally, it was thought that the ORN arose in the presence of radiation, trauma, and infection., Later, Marx  proposed the widely accepted theory that radiation causes endarteritis resulting in tissue hypoxia, hypocellularity, and hypovascularity which, in turn, causes tissue breakdown, causing chronic nonhealing wounds. Evidence suggests that there are additional factors involved in the etiology of this disease. It is thought that osteoclasts suffer the radiation effects before the vascular disruption and that the suppression of bone metabolism is a critical component in the development of ORN. Since Marx  described the pathophysiology of ORN, no other explanation was given until Delanian et al. published the fibroatrophic theory in 1993. They described three differentiated phases. The first is a prefibrotic phase, in which changes in endothelial cells with an acute inflammatory response predominate. The second is a constitutive phase, in which an abnormal fibroblast activity exists and in which the extracellular matrix becomes disorganized. Finally, at the end of this fibroatrophic phase, the tissue tries remodeled as fragile scar tissue, which has an inherent risk of reactive inflammation late in cases of local injury can cause bone necrosis. ORN affects between 2% and 22% of patients that receive radiotherapy in the region of the head and neck, and the severity of involvement and effect on the patient range from cases completely asymptomatic to those that cause severe pain, disfigurement, and functional impairment of the jaws seriously altering the quality of life.
Large bone defects in the mandible due to atrophy, trauma, or after large tumor resections, can generate a number of problems, such as distortion of facial contour, loss of lip support, dental malocclusions as well as functional alterations.
With the advent of microvascular free flaps is provided a predictable method to restore the bone and soft tissue in cases of large and complex defects. The possibility of placing dental implants in these areas overcomes the problems associated with the dental rehabilitation with dental prosthesis. There are several donor sites that have been used for mandibular reconstruction, such as the iliac crest flap, radial flap, fibula, and parascapular flap. Among these alternatives, the vascularized fibula flap is one of the bony flaps, which is most employed since due to its length; it has demonstrated high reliability and adaptability for the reconstruction of maxillo-mandibular defects, its long vascular pedicle, the segmental blood supply and its ability to be bent to conform to the shape of the mandible.
Even though recent studies have shown that osseointegration in irradiated bone is often possible, it remains uncertain with high failure rates, probably because the number of vessels in the oral mucosa decrease leading to tissue weakness, reason which the surgeon and the prosthodontist should pay special attention when raising the flap and placing the implants., To date, we do not know of published work in the indexed medical literature that describes exclusively the bony changes and the evolution of dental implants placed in patients with ORN after reconstruction with microvascularized fibula. The aim of this study is to present the evolution of a 40-year-old male patient, who underwent a mandibular reconstruction with fibula free flap after an oncological resection which showed a picture of ORN managed with surgical therapy and hyperbaric oxygen (HBO) as adjuvant therapy and on whom rehabilitation was then performed with implant-supported prostheses.
Male patient 40-year-old with antecedent of heavy smoking and casual drinking, who in October 2001 consulted to present a clinical picture consistent in ulcer on the floor of the mouth with extension to lingual raphe without palpation of cervical lymphadenopathy. Incisional biopsy of the lesion was performed, which showed that microscopically a fragment is partially coated by malpighian epithelium showing an epithelial neoplastic proliferation with signs of squamous differentiation infiltrating the chorion consisting of atypical cells, with an end histopathological diagnosis of well-differentiated epidermoid carcinoma. Computed tomography (CT) showed an injury in floor of mouth in midline, poorly demarcated of approximately 2.5 cm, and bone involvement at the level of the mandibular symphysis with absence of significant lymphadenopathy (T4, N0, Mx). In November 2001, the patient underwent surgery, performing on him a bilateral cervical lymph node functional dissection, resection of the tumor with segmental mandibulectomy from 36 to 45, and immediate reconstruction with microvascularized osteomyocutaneous flap obtained from the left fibula bone with a skin island that is placed intraoral [Figure 1]. The flap is stabilized by 6 mini plates and monocortical titanium screws. He received complementary cervicofacial radiotherapy which from January to February 2002. Radiotherapy was carried out at a dose of 50 Gy with X-ray 6MV using two lateral fields, the right lateral field consisting of 14 cm × 10 cm and the left lateral field consisting of 14.5 cm × 10 cm (fractionation-5 cGy × 200 cGy). Sixteen months after successive revisions with good evolution without local or lymph node recurrence, an orocervical fistula was observed with secretion of pus, which did not close in spite of local cures, because nonunion (mobility of bone fragments) in the junction of the fibula with the jaw on its left side. Extension studies were performed, and in the MR, one abscessed area was observed under the skin island of the fibula flap in the left side, without evidence of recurrences. In the mandibular CT, areas of bone necrosis and in the orthopantomography (OPG) [Figure 2] areas of bone sequestration in the edge of the fibula bone on the left side of the jaw were observed. The antibiogram showed the presence of Coagulase Negative Staphylococcus. This patient was diagnosed as postradiotherapy ORN of fibula bone for mandibular reconstruction. In March 2003 after establishing antibiotic treatment and removing some screws that had become exposed, the patient was operated under general anesthesia by the left cervicotomy for exposition of the fibula bone, removal of fragments of necrotic bone and exposed miniplates, and filling the medullary canal of the bone with calcium sulfate paste. The patient was referred to adjunctive treatment with HBO. This treatment begins in July 2003 at the rate of 1 daily session of 1 h duration, breathing 100% oxygen to 2.5 absolutes atmospheres during 30 days. After treatment with HBO, the patient reports pain relief. In June 2005, after 11 months without clinic, the patient returns to relapse exhibiting bone sequestration at the jaw reason why a second cycle of 15 sessions of HBO and subsequent intra- and extra-oral sequestrectomy, curettage of the area, and removal of osteosynthesis material is carried out, which definitely stabilizes the process with a favorable outcome. Successive controls with radiography and CT indicate a complete remission of the process, showing a good bone consolidation. After 14 months without evidence of ORN, the patient requests placement of 4 implants (4.25 mm × 11.5 mm) with external hexagon connection and surface resorbable blasting media (Mozo Grau, SL, Spain) on the fibula bone for the rehabilitation with dental prosthesis. The surgery is performed transmucosal without lifting flaps to avoid compromising bone vacularización and carrying out the regular drill protocol with copious irrigation. Eight months after surgery, implants osseointegrated checked perfectly with good stability, so healing screws [Figure 3] are placed. One month later, a removable dental prosthesis on bar without mucous support is made and adapted [Figure 4]. After 7 years of evolution, the patient remains free of disease and with stability of his dental rehabilitation [Figure 5].
|Figure 2: Fibula with signs of osteoradionecrosis. Orthopantomography where areas of bone rarefaction in the fibula flap are observed after removing the miniplates and screws on the left side|
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|Figure 3: Orthopantomography 8 months after insertion of the implants. Orthopantomography with good evolution of osteoradionecrosis without progression and with increase of bone density|
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| Discussion|| |
In ORN, a endarteritis resulting in tissue hypoxia, hypovascularity, and hypocellularity is produced, which in turn causes tissue breakdown, triggering in chronic nonhealing wounds., This condition may even appear several years after the radiotherapy treatment, may occur spontaneously, and their degree of involvement and effect on the patient may vary from completely asymptomatic cases where the ORN can be demonstrated radiologically without any involvement in the oral mucosa or cervicofacial skin, to cases that cause severe pain, disfigurement, and functional impairment of the jaws seriously affecting the quality of life.
Considering the pathophysiologic triad of hypoxia, hypocellularity, and hypovascularity given by Marx 1983, a logical solution to this etiology to improve vascularization and remove devitalized tissue is the use of HBO, which could be used as monotherapy or as adjunctive therapy depending on the features presented or the patient's response to it. However, in the literature, it seems clear that the advanced stages of ORN require aggressive surgical treatment, and the only HBO therapy has minimal or benefit null. Some publications have even suggested that therapy with HBO may not have a clear role in the treatment of advanced ORN when a vascularized reconstruction has been performed. Nevertheless, the use of HBO in early and intermediate stages of ORN is still important because the benefit appears to be based plainly on numerous retrospective studies.,,,, These favorable results published in several retrospective studies share the argument that the purpose of the use of HBO is to increase the gradient of oxygen in the blood to the tissues, which enhances the diffusion of oxygen to hypoxic tissues. Hyperoxygenation of irradiated tissues stimulates angiogenesis, fibroblast proliferation, and collagen formation and therefore, promoting the osteogenesis.,
Furthermore, increased oxygen tension is bactericidal and bacteriostatic. Therefore, cases of ORN which are complicated or refractory to treatment should be treated with aggressive surgical resection of all affected tissues (hard and soft) with healthy margins and if necessary to perform reconstruction with microsurgical flaps. This aggressive surgical treatment is often performed without using therapy of HBO (before or after surgery) or debridement, because patients who present with advanced disease do not benefit from OHB., It has been speculated that this method of therapy improves the viability of the remaining bone in residual areas partially involved with ORN. This approach differs significantly from protocol of treatment of Marx in which the OHB before and after surgery advocates, and the reconstruction performed does not involve the use of vascularized bone flaps. However, the use of HBO in early and intermediate stages of ORN remains important.
Even though most of the studies available reveal that radiation reduces the number of osteogenic cells, alter the ability of cytokines, and delays and impair the capacity of bone remodeling, recent studies have shown that osseointegration of dental implants in irradiated bone is common despite the high failure rates., Integration of dental implants in irradiated bone depends not only on interindividual variations but also on the influence of the radiation parameters. The initial dose of radiation delivery becomes an effective dose that itself has a biological effect under the influence of three main parameters: type of radiation, tissue type, and radiation protocol. Different forms of radiation do not produce the same biological effects, examples of this are the conflicting outcomes obtained in the studies about the outcome of dental implants. From the available literature, some authors have recommended that implant surgery is safe in patients who have been irradiated at lower doses of 50–55 Gy. On the other hand, patients with irradiation <55 Gy should not be rehabilitated with osseointegrated implants.,,, In our case, the patient received radiation to doses up to 50 Gy. Patients with doses of extremely high radiation (>120 Gy) have low survival of implants and high risk of ORN. However, Gy dose is misleading because this name does not consider the number of fractions delivered. If the term “cumulative radiation effect” is applied and calculated a more reliable estimate of the radiation dose can be obtained. With a cumulative radiation effect below18–20 (corresponding to 48–65 Gy. Given as radiotherapy of standard fractionated) relatively few implants fail while implant failures increases at higher doses. With doses cumulative radiation effect higher 40 (120 Gy, in standard fractionated), implants fail.
With regard to the time between radiotherapy and implant surgery, literature has documented that this is an important factor in the commitment of osseointegration. It has been shown that the closer the implant surgery of the end of the radiation is performed, greater the probability of failure. Therefore, the best results are achieved when the implants are placed sometime after the irradition., The early implantation after irradiation to high dose is not commonly recommended since the aim to improve the quality of life with the placement of the dental implant cannot justify the increased risk of ORN. Nevertheless according Marx and Johnson., the irradiation of decades ago seems to have a more negative effect on survival of implants that radiotherapy recently administered due to progressive endarteritis taking place in the irradiated bone, which is known to increase with time. However, most of the authors agree that a long interval between radiotherapy and the implant placement is preferable. The maximum bone damage occurs at 6 months after irradiation. Therefore, implants should be placed at least 1 year later.
Implant-related factors also affect its integration in irradiated bone. Several studies have shown that the rates of failure for short implants are increased when these are placed in the irradiated bone. Very short implants (3–7 mm.) are particularly prone to failure. Therefore, the use the longest possible implant is recommended. With regard to retention of the prosthesis has been shown that the survival of the implants in the irradiated bone depends on a high degree of this variable. Most implant survival is observed for prosthesis of fixed retention, and lower survival of the implant is observed for the removable prosthesis with extensions in cantilever. Nevertheless, a conventional fixed prosthesis may be more difficult to adapt due to new anatomical conditions after oncological surgery. Furthermore, a high number of implants is also required, which is not always possible in these patients, this added to that the follow-up and oral hygiene are more difficult, which is considered to be critical for long-term success. With regard to soft tissue, it is important to note that due to the radiotherapy, hyposalivation could lead to a significant decrease of blood vessels and mucous membrane irritation causes the tissues to be more susceptible to trauma mainly in patients with removable prosthesis.
We present this case, due of its favorable development during 7 years follow-up. However, it is important to note that according to the literature, the failure of implants on irradiated bone, increase during periods of prolonged follow-up. This phenomenon makes it important to define the follow-up time of each study when discussing the benefits and disadvantages of the surgery of implants in irradiated bone. Reports of success with only 2–3 years of follow-up may give the false impression that the implant surgery in irradiated bone is simple and uncomplicated.
| Conclusion|| |
Microvascularized fibula bine can receive a functional dental rehabilitation with osseointegrated implants even if there has been a previous history of properly treated ORN.
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Conflicts of interest
There are no conflicts of interest.
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