Technique For Mandibular Reconstruction Research Articles

The CAD–CAM technique for mandibular reconstruction: An 18 patients oncological case-series

BackgroundModern techniques for mandibular reconstruction, such as CAD–CAM, offer new solutions for planning of reconstructive surgery in relation to the aesthetic outcome and the prosthetic rehabilitation. MethodsCAD–CAM reconstruction procedures using vascularised bone free-flap transfers and surgical guides to cut the mandible and fibula were performed in 18 cases of neoplasms. The planned surgery was used to design and manufacture customised surgical devices. ResultsThe mean follow-up was 12 months. All patients, except one, are alive without disease at the time of writing. Reconstructive microvascular flap survival was 100%. No major or minor microvascular complication occurred. No donor site complication was observed. ConclusionsCAD–CAM technology is a very useful way to obtain the native morphology of the mandible, especially when both bi-dimensional and tri-dimensional defects occur. The reconstruction protocol presented offers several benefits and few disadvantages, which are discussed in the article.

Initial Experience With rhBMP‐2 Delivered in a Compressive Resistant Matrix for Mandibular Reconstruction in 5 Dogs

To document cumulative initial experience and long-term follow-up of the use of rhBMP-2/CRM for reconstruction of large mandibular defects (≥5 cm) in dogs. Retrospective case series. Dogs (n = 5). Medical records (October 1999-April 2011) of dogs that had mandibular reconstruction for defects/resections of ≥5 cm using rhBMP-2/CRM were reviewed. Signalment, preoperative assessment/rationale for mandibular reconstruction, surgical methods, postoperative assessment of the reconstruction (evaluation of occlusion), and complications were recorded. A definitive histologic diagnosis was obtained in dogs that had mandibular resection for mass removal. Long-term complications were determined. A minimum time frame of 2-year in-hospital follow-up was required for case inclusion. Mandibular reconstruction was successfully performed in all dogs' defects where gaps of 5-9 cm were bridged. Surgical reconstruction rapidly restored cosmetic appearance and function. All dogs healed with new bone formation across the gap. New bone formation was present within the defects as early as 2 weeks after surgery based on palpation, and new bone formation bridging the gap was documented radiographically by 16 weeks. Minor complications occurred in all dogs in the early postoperative period, and included early firm swelling and gingival dehiscence in 1 dog; late plate exposure in 3 dogs; and exuberant/cystic bone formation in 2 dogs (related to concentration/formulation of rhBMP-2/CRM). Two dogs had minor long-term complications of late plate exposure and a non-vital canine tooth; the plates and the affected canine tooth were removed. Long-term in-hospital follow-up was 5.3 years (range, 2-12.5 years); further long-term telephone follow-up was 6.3 years (range, 2-12.5 years). All owners were pleased with the outcome and would repeat the surgery again under similar circumstances. The efficacy and success of this mandibular reconstruction technique, using rhBMP-2/CRM with plate fixation, was demonstrated with bridging of large mandibular defects regardless of the underlying cause, and with excellent cosmetic and functional results. Complications were common, but considered minor and easily treated. The complications encountered revealed the importance of tailoring the use of BMPs and fixation methods to this specific anatomic location and indication.

The Horizontal and Stepped Osteotomy Technique for Mandibular Reconstruction Using Fibular Free Flap

The mandible is an important component of the orofacial skeleton, and resection of part of the mandible as part of head and neck oncological procedures can have dramatic impact on both function and cosmesis. In this article, we describe a new technique in the resection osteotomy and flap fixation that improves the stability and aesthetic outcome of the reconstruction. The mandibular resection is performed utilizing a horizontal osteotomy above the mandibular angle on one side and a stepped body or angle osteotomy on the other side. Our technique is unique as it allows flexibility in adjusting the chin point projection to give the best possible aesthetic outcome; it allows more bone-to-bone contact, which increases the stability; it reduces rotation; and it allows for use of miniplate fixation, facilitating future rehabilitation with implants. We have been using this technique with great success in our hospital, and we recommend its use for its improved flexibility, stability, and aesthetic outcome.

Composite Mandibulectomy: A Novel Animal Model

Objective: The safe and reliable reconstruction of composite mandibulectomy defects is a topic of significant interest. Unfortunately, a well-established small-animal model of the segmental composite mandibulectomy does not exist. We describe a reliable animal model that can be utilized to study mandibular reconstruction techniques, including atuogenous bone grafts and biomaterials. Method: Prospective analysis of survival-operations in the rat model (4-month Sprague Dawley Rattusnorvegicus). A detailed, stepwise description of surgical technique and relevant intraoperative anatomy is presented, utilizing photographic and radiographic images. Postoperative management, early pitfalls, surgical complications and future applications are discussed. Results: A total of 72 operations were performed by a single individual between July and October 2010. Two intraoperative and seven postoperative complications were recognized. There were 4 orocutaneous fistulas, 1 abscess, and 1 seroma. There were 3 fatalities; deaths were attributed to anesthetic complications (2, intraoperative) and foreign-body aspiration (1, postoperative). Conclusion: The novel animal model described here, reliably replicates the en-bloc segmental mandibular defects seen in our patient population. It can be manipulated to achieve a wide variety of research objectives, including the evaluation of biomaterials and tissue engineering techniques.

Mandible reconstruction

The purpose of this article is to review current microvascular mandibular reconstruction techniques and recent literature on the advances of tissue engineering as they relate to mandibular reconstruction. Microvascular reconstruction continues to be the standard of care for complicated mandibular reconstruction in major ablative defects of the head and neck. Several recent modifications of current microvascular techniques offer significant improvement in the quality of reconstructions currently being performed. Advances in tissue engineering are currently not widely applicable clinically due to a number of factors; however, the technology offers promising advances in the management of mandibular continuity defects in the future. Microvascular reconstruction of the mandible represents the most significant advancement in technique in the current era. Tissue engineering offers a promising future to improve outcomes and decrease patient morbidity. Future investigations regarding this new technology will provide information on the utility and feasibility of tissue engineering in mandibular reconstruction.

Techniques on Modeling the Vascularized Free Fibula Flap in Mandibular Reconstruction

In mandibular reconstruction with bone grafts, the functional and aesthetic outcomes are clearly influenced by reconstructive techniques. Vascularized free fibular flaps are considered the most suitable choice for mandible reconstruction because of their good aesthetic and functional outcomes. Several techniques have been described in literature. According to various authors, shaping of the fibular graft can be performed by means of computer-aided design/computer-aided modeling procedures for the evaluation of the presurgery anatomy and three-dimensional models of fibula graft. However, these models are expensive, require a strict realization of the programmed intervention, and are not easily adaptable to a surgical treatment different from the planned one. We report our experience on a technique for mandibular reconstruction using a free fibular flap, obtained by modeling a template on the resected mandible. Our operative technique consists of 5 steps: preplating, resection, template modeling, contouring of the fibula, and fixing the flap on the mandible.Template modeling is performed to record the length of the resected bone, the mandibular curvature on the 3 space planes, and the width of the basal bone. On the basis of the template, the fibula flap was modeled while still attached to the pedicle. The plates, positioned at the level of the fibular osteotomies, were preformed to make the fibula precisely fit in the template. Once the fibula was shaped, mandibular reconstruction was completed by positioning the fibula graft on the mandibular stumps. Bone graft modeling by means of template is a rapid, safe, and flexible method to reconstruct the mandible.

Feasibility of alloplastic mandibular reconstruction in patients following removal of oral squamous cell carcinoma

Microvascular bone grafts have evolved as the preferred technique for mandibular reconstruction in irradiated tumour patients. However immediate reconstruction by bridging plates remains an option for patients whose clinical condition is not favourable for microsurgical reconstruction. This retrospective study evaluates the performance of alloplastic mandibular reconstruction in patients following removal of oral squamous cell carcinoma. Three hundred and thirty-four patients with primary (biopsy proven) oral squamous cell carcinoma without distant metastasis (stages II-IV), who were all treated by segmental mandibular resection and reconstruction by means of a titanium bridging plate were included. Two hundred and seventy-two patients received preoperative treatment, consisting of concomitant radiochemotherapy (RCT) (n=228), chemotherapy (n=34) and radiotherapy (n=10). Median follow-up was 5.1 years (min 0.3, max 18.0). The median 2-year-disease-specific survival rate (DSS) was 81.6%. Five-year-DSS and 10-year-DSS was 71.8% and 62.0%, respectively. One hundred and thirty-six plates were removed due to infection with intra- and/or extraoral exposure, seven plates because of fracture. Preoperative RCT (p=0.027), mandibular defects including the symphysis (p=0.016) and heavy smoking at the time of diagnosis (p=0.042) were associated with infection-related failure of the reconstruction plates. Reconstruction of mandibular defects with titanium bridging plates seems crucial in heavy smoking tumour patients with preoperative RCT as well as in mandibular defects including the symphysis.

Reconstruction mandibulaire en cancérologie : état actuel et perspectives

Introduction Mandibular reconstruction in head and neck oncology uses a number of techniques whose results are inconsistent and whose indications do not benefit from consensus. Materials and methods A review of the literature allowed us to assemble the available knowledge on current mandibular reconstruction techniques, their functional results, and the research perspectives. Results and discussion Marginal resections lead to dental rehabilitation problems, which can be palliated by alveolar enhancement techniques but whose results have not been validated in cases subjected to irradiation. Reconstruction of segmental substance loss is warranted by the repercussions on the vital prognosis when it is anterior and on the quality of life when it is posterior. The ideal means of reconstruction is the free fibular flap, which is limited by cost, morbidity of the donor site, and selection of the patient's surgical team. For these reasons, it may be necessary to turn to pedicled osteo-myocutaneous flaps, abandoned because of their reputedly very high failure rate, but few have been reported in the literature. Conclusion Poor functional results of mandibular reconstruction plates make this a last-resort solution. Tissue engineering is currently the most promising line of research. It runs counter to the principles of oncology itself because postoperative radiotherapy reduces the osteoinduction potential of the biomaterials proposed.

A Comparison of Vascularized Fibular Flap and Iliac Crest Flap for Mandibular Reconstruction

Segmental mandibular defects, which are caused either by ablative surgery or trauma, are usually accompanied by different degrees of skin, soft tissue or mucosa losses. The reconstruction of such defects requires complicated surgical procedures. An ideal mandibular reconstruction method must support the insertion osseointegrated dental implants which is necessary for total oral rehabilitation. The soft tissue defect should also be reconstructed if it accompanies the bony defect. We performed 37 mandibular reconstructions using either vascularized iliac crest flap or fibula flap. Sixteen of 24 patients who underwent mandibular reconstruction using iliac crest flap, and 3 of 13 patients who has been reconstructed with fibula flaps, had mandibular defects involving skin and/or mucosa. Both techniques were compared regarding patients records such as hospital stay, operation time, defect size, etiopathogenesis, skin paddle, blood transfusion, and complication rates. Self-assessment questionnaires were also used to evaluate aesthetic and functional results. When 2 different mandibular reconstruction techniques are compared regarding patient records, the complication rate of fibula flap was less than the iliac crest flap. Functional and aesthetic results also showed that oral continence, social activities, and facial appearance rates of fibula flap were superior to iliac crest flap. Lower complication rates of fibula flap group may be associated with patients' higher satisfaction rate. Both flaps are commonly used in mandibular reconstruction, however, many parameters including defect localization, defect size, presence of soft tissue defect should be considered.

Management of mandibular basilar fracture as a complication of tumor surgery

Fracture of the mandible basilar bone after a conservative resection of an ameloblastoma is an unusual postoperative complication and poorly cited in literature, since the radical resection is the most common treatment used for this condition. We present a case dealing with this complication, showing a technique for mandibular reconstruction that creates good results in five years of follow-up.

Experimental study of mineralization in mandibular bone distraction with irradiation during the consolidation phase

This study aimed at assessing the effect of radiotherapy on regenerated bone mineralization and consolidation obtained by mandibular bone distraction. The planned application was a new immediate mandibular reconstruction technique in defects following surgery for oral cavity tumours requiring postoperative radiotherapy. Ten sheep underwent bilateral mandibular bone distraction (control group). A second group of 6 sheep (study group) had bilateral mandibular bone distraction followed by irradiation on the 21st postoperative day. The animals were sacrificed on the 60th postoperative day. Radiographic and histomorphometric studies were performed. In the control group, 9 distraction sites out of 20 were consolidated. In the irradiated group, 9 out of 12 were consolidated. Histomorphometric analysis did not demonstrate any statistically significant difference between the osseous and cartilaginous samples, the trabecular thickness of the new bone, or the osteoid surface of basal bone in the control and test groups (p=0.126, 0.247, 0.792, 0.082). However, the osteoid surface of the regenerated bone in the test group was statistically smaller (p=0.017) than in the control group. In this experiment, radiotherapy did not hinder bone mineralization or consolidation following distraction of mandibular bone receiving irradiation on the 21st postoperative day. Bone distraction could be proposed for the repair of mandibular defects following surgery for oral tumours which require early postoperative radiotherapy.

Mandibular reconstruction in 2004: an analysis of different techniques.

The field of mandibular reconstruction has evolved dramatically over the past fifty years. Numerous advances in microsurgical technique, plating technology and instrumentation, and an understanding of donor site angiosomes have made consistent and reliable mandibular reconstruction possible. Refinements in technique continue to improve the functional and aesthetic outcomes of oromandibular reconstruction. This review discusses the current state-of-the-art techniques for mandibular reconstruction and highlights the latest innovations in technique. The most common indication for oromandibular reconstruction remains ablative surgery for advanced neoplastic processes of the oral cavity and oropharynx. Reconstruction of these complex three-dimensional composite bony and soft-tissue defects is paramount for rehabilitation of form and function. Vascularized osseous free tissue transfer is the state-of-the-art for mandibular reconstruction. The long-term excellent functional and aesthetic outcomes of this technique have recently been reported. The most commonly used free flaps for mandibular reconstruction are the fibula, iliac crest, and scapula. Each of these typically accepts endosseous implants improving functional outcomes. The use of mandibular reconstruction plates and coverage with a soft-tissue flap remains a reconstructive option for selected patients. The latest refinements in technique include temporary intraoperative external fixation, the use of periosteal free flaps, distraction osteogenesis, and development of biodegradable biopolymer scaffolds for mandibular defects. Oromandibular reconstruction, although a challenge for the head and neck reconstructive surgeon, is now reliable and highly successful with excellent long-term functional and aesthetic outcomes.

Indications for the AO plate with a myocutaneous flap instead of revascularized tissue transfer for mandibular reconstruction.

Our preferred technique for mandibular reconstruction uses a revascularized osseomyocutaneous flap. However, to reconstruct small lateral defects in dentulous patients, the AO mandibular reconstruction plate (MRP) is used. Its advantages include quick, reliable placement without a donor site or the need for advanced technical training. This review examines 16 patients who underwent primary mandibular reconstruction after ablative oncologic surgery using an AO MRP without a bone graft. The average follow-up was 32 months. Twelve patients (75%) had successful reconstructions, while 4 (25%) developed serious complications resulting in failure of the MRP. The most significant factor limiting rehabilitation was disease progression, affecting 12 (75%) of the 16 patients. In this subgroup of selected patients with small (< 6 cm) lateral mandibular defects, useful dentition, and advanced disease, or whose general medical condition precludes prolonged general anesthesia, primary mandibular reconstruction using an AO MRP and a myocutaneous flap without a bone graft is a viable reconstructive alternative.

Plating techniques for mandibular reconstruction

The alloplastic reconstruction plate can provide acceptable primary reconstruction of the bony mandibular defect. Used in combination with myocutaneous flap reconstruction or free tissue transfer, this form of mandibular reconstruction is reliable, technically easy, and, in the properly selected patient, represents a sound approach that allows excellent postoperative esthetics and function. This reconstruction modality does not interfere with postoperative radiation treatment and does not prejudice delayed reconstruction with vascularized bone in those patients who survive their cancer. The alloplastic reconstruction plate can provide acceptable primary reconstruction of the bony mandibular defect. Used in combination with myocutaneous flap reconstruction or free tissue transfer, this form of mandibular reconstruction is reliable, technically easy, and, in the properly selected patient, represents a sound approach that allows excellent postoperative esthetics and function. This reconstruction modality does not interfere with postoperative radiation treatment and does not prejudice delayed reconstruction with vascularized bone in those patients who survive their cancer.

Evaluation of mandibular reconstruction techniques following resection of malignant tumors in the oral region

Over the past 15 years, reconstruction following excision of malignant oral tumors was performed on 27 patients with segmental resection and five patients with hemiresection of the mandible. Following segmental resection, the mandible was reconstructed using an autogenous bone graft in eight patients in whom the surrounding soft tissues were fairly well preserved. Bony union was achieved in six of them. In the remaining two, the graft was removed because of postoperative infection, and one patient underwent secondary bone grafting. A pedicled myocutaneous flap and bone graft was used in seven patients who underwent extensive resection of the surrounding soft tissue. Bony union was achieved in three patients, and one developed pseudoarthrosis. The graft was removed in the remaining three because of postoperative infection. Reconstruction with only a metallic plate for stabilization of the mandible was carried out in six aged or sarcoma-affected patients. In two of them, the postoperative course was uneventful for 4 to 7 years. In the remaining four patients, plate removal was required because of exposure or tumor recurrence. In 5 of 11 patients in whom reconstruction was carried out with a combination of a pedicled myocutaneous flap and metallic plate, the postoperative course was uneventful for 2 to 8 years. Two of these five patients underwent secondary bone grafting. In four of the remaining six patients, the plate was removed because of exposure or improper adaptation to the stump. Two others died of disseminated intravascular coagulation syndrome within 1 month. A prosthesis was used more frequently by patients when reconstruction was performed using a pedicled osteomyocutaneous flap. The metallic reconstruction plate was helpful for restoring mandibular contour. When there was insufficient tissue to cover the plate, exposure was liable to occur because of tension exerted on the covering tissues. Therefore, a plate should be placed as medial as possible when using a thick myocutaneous flap.

Vascularized parietal bone flaps: A new dimension in mandibular reconstruction

The ultimate objective, when treating a mandibular defect, is to restore completely the function and cosmetic appearance of the face. The reconstruction must include bone from a similar source, good in quality and shape and living, to resist infection and the continuous stress that takes place in the mandible during mastication. Our technique for mandibular reconstruction using bone from the calvarium, of full thickness to receive implants and living because it is pedicled on the galea (from the superficial temporal artery) is reported. Our criteria for reconstruction, and the analysis of all the cases reconstructed with the technique mentioned above, is presented. Emphasis is placed on the good shape of this bone flap, its vascularization studies (compared with those in other techniques) and the high rate of success in both cosmetic and functional results.

Mandibular reconstruction using a special plate: Animal experiments and clinical application

The use of a variety of procedures and techniques for mandibular reconstruction suggest that no satisfactory solutions have been found with regard to restoration of functional stability, joint function and masticatory function. In view of the varied clinical problems involving restoration of mandibular function, we developed our own reconstruction plate, a condylar prosthesis, and a reconstruction plate with a condylar head. The U-shaped notches of the reconstruction plate permitted universal adaptation of the plates by means of special pliers. The most important result of the animal experiments was the achievement of stability under functional stress. This made intermaxillary fixation unnecessary. The preliminary experience in our clinical cases with the reconstruction plate showed a reduction of masticatory disability. The clinical results corresponded well with those of the animal experiments, and thus confirmed the value of the experimental model chosen.