Mandible reconstruction:

Can jaw bone healed from chronic sclerosing osteomyelitis be considered healthy when planning dental implants? Case report with 20-year follow-up

Introduction and importance

Extraction of mandibular third molars can lead to complications such as chronic sclerosing osteomyelitis (CSO), an inflammatory bone marrow disease that tends to progress. CSO involves the cortical plates and often the periosteal tissues and is caused by a variety of microorganisms, including Corynebacterium spp. The treatment of chronic osteomyelitis (CO) and CSO remains challenging, as there is no universal treatment protocol. This case report investigated whether jaw bone that has healed from chronic sclerosing osteomyelitis can be considered healthy bone when planning dental implants.

Case presentation

A 21-year-old Caucasian woman developed CO and CSO after third molar surgery.

Clinical discussion

A combination of alveolar ridge bone resection, extraction of teeth 47-32, and long-term specific antibiotic therapy against Corynebacterium spp. was administered. An attempt at preprosthetic alveolar ridge reconstruction with an anterior superior iliac crest bone graft resulted in graft failure and the patient refused further harvesting procedures. Implantation in the intraforaminal zone also resulted in the loss of two implants after loading. Finally, inferior alveolar nerve transposition resulted in the successful reimplantation of two implants, which were fully functional almost 11 years later.

Conclusion

This case report presents the treatment history of this patient. With a longitudinal observation period of greater than 20 years, the results of this case demonstrate the successful treatment of bone with CO, CSO, and Corynebacterium spp. infection. Following the removal of infected bone, radical debridement, and long-term antibiotic therapy, bone health was restored.

Risk Factors for Plate Extrusion After Mandibular Reconstruction With Vascularized Free Flap

PURPOSE

Plate extrusion after mandibular reconstruction is a complication that imposes significant morbidity on the patient. The goal of this study is to estimate the incidence of plate extrusion after mandible reconstruction with a vascularized free flap and to identify the factors associated with plate extrusion.

METHODS

This was a retrospective cohort study involving patients who underwent mandibular reconstruction from October 2008 to July 2019 at LAC + USC or Keck Hospital of USC. Inclusion criteria were age ≥ 18 years, single-stage mandibular reconstruction with vascularized free flap, and follow-up of at least 12 months. Relevant demographic, intraoperative, and postoperative data were collected. The primary outcome was postoperative plate extrusion within the 12-month follow-up. Descriptive, univariate, and multivariate analyses were performed. Statistical significance was set at P ≤ .05.

RESULTS

A total of 102 patients were included in this study. The majority received a fibula free flap (90%) for a malignant neoplasm (76%). All patients had at least 12 months of follow-up. The rate of plate extrusion was 16%, with the majority of those patients undergoing plate removal (69%). After adjusting for postoperative fistula, soft tissue, and length of hospitalization, we found that any history of smoking (odds ratio = 12.8; confidence interval, 1.57 to 104.2), number of osteotomies (odds ratio 3.07; confidence interval, 1.09 to 8.6), flap nonviability (odds ratio = 18.2; confidence interval, 2.22 to 148.8) were associated with plate extrusion on multivariate analysis. Postoperative soft tissue infection approached significance.

CONCLUSIONS

This study demonstrates that smoking history, number of osteotomies, and flap nonviability are associated with plate extrusion after mandible reconstruction. Performing fewer osteotomies when possible to avoid excessively small flap bone segments and minimizing postoperative complications may improve long-term outcomes after mandibular reconstruction.

Enhancement of BMP-2 and VEGF carried by mineralized collagen for mandibular bone regeneration

Repairing damage in the craniofacial skeleton is challenging. Craniofacial bones require intramembranous ossification to generate tissue-engineered bone grafts via angiogenesis and osteogenesis. Here, we designed a mineralized collagen delivery system for BMP-2 and vascular endothelial growth factor (VEGF) for implantation into animal models of mandibular defects. BMP-2/VEGF were mixed with mineralized collagen which was implanted into the rabbit mandibular. Animals were divided into (i) controls with no growth factors; (ii) BMP-2 alone; or (iii) BMP-2 and VEGF combined. CT and hisomputed tomography and histological staining were performed to assess bone repair. New bone formation was higher in BMP-2 and BMP-2-VEGF groups in which angiogenesis and osteogenesis were enhanced. This highlights the use of mineralized collagen with BMP-2/VEGF as an effective alternative for bone regeneration.

Functional Reconstruction of Mandibular Segment Defects With Individual Preformed Reconstruction Plate and Computed Tomographic Angiography-Aided Iliac Crest Flap

PURPOSE

With the development of imaging technology and computer-assisted surgery in oral and maxillofacial surgery, digital technology is widely used in vascularized bone flap grafts for mandibular reconstruction. The aim of this study was to use digital technology throughout the treatment process to show that digital techniques can provide a reliable and accurate match between the mandible and the iliac crest flap to achieve functional reconstruction of mandibular segment defects.

MATERIALS AND METHODS

Twenty patients underwent 3-dimensional (3D) computed tomography (CT), mirroring technology, 3D model prototyping, and CT angiography (CTA) for treatment planning. Individual preformed reconstruction plates were fabricated and iliac crest flaps were designed preoperatively. After complete resection of the mandibular lesion, the iliac crest flap was shaped to reconstruct the mandibular defects.

RESULTS

During follow-up (range, 12 to 36 months), the facial shape, facial symmetry, and mouth opening of all patients recovered well. The 3D CT reconstruction also was evaluated for height, width, length, and bone healing of the iliac crest flap. Postoperative examination showed ideal bone union between the iliac crest flap and the mandible at 6 months. Nine patients received implant-supported fixed dentures to restore dentition. After follow-up, all patients were satisfied with their facial esthetics and function. The new mandible provided a suitable 3D position for implant-supported fixed partial dentures.

CONCLUSION

Use of digital techniques throughout the course of treatment improves the predictability and convenience of functional mandibular reconstruction. Individual preformed reconstruction plates and CTA effectively guaranteed the accuracy of iliac flap preparation.

Electron beam melting in the fabrication of three-dimensional mesh titanium mandibular prosthesis scaffold

The study was designed to fulfill effective work-flow to fabricate three-dimensional mesh titanium scaffold for mandibular reconstruction. The 3D titanium mesh scaffold was designed based on a volunteer with whole mandible defect. (1) acquisition of the CT data; (2) design with computer aided design (CAD) and finite element analysis (FEA). The pore size and intervals with the best mechanic strength was also calculated using FEA. (3) fabrication of the scaffold using electron beam melting (EBM); (4) implantation surgery. The case recovered well, without loosening and rejection. Additionally, 12 mandibular defect model beagles were used to verify the results. The model was established via tooth extraction and mandibular resection surgeries, and the scaffold was designed individually based on CT data obtained at 2 weeks after extraction operation. Then scaffolds were fabricated using 3D EBM, and the implantation surgery was performed at 2 months after extraction operation. All the animals healed well after implantation, and the grafted mandibular recovered well with time. The relevant parameters of the grafted mandibular were nearly to the native mandibular at postoperative 12 months. It is feasible to fabricate mesh titanium scaffold for repairing mandibular defects individually using reverse engineering, CAD and EBM techniques.

Heterotopic bone formation in the musculus latissimus dorsi of sheep using β-tricalcium phosphate scaffolds: evaluation of different seeding techniques

Osseous reconstruction of large bone defects remains a challenge in oral and maxillofacial surgery. In addition to autogenous bone grafts, which despite potential donor-site mobility still represent the gold standard in reconstructive surgery, many studies have investigated less invasive alternatives such as in vitro cultivation techniques. This study compared different types of seeding techniques on pure β-tricalcium phosphate scaffolds in terms of bone formation and ceramic resorption in vivo. Cylindrical scaffolds loaded with autologous cancellous bone, venous blood, bone marrow aspirate concentrate or extracorporeal in vitro cultivated bone marrow stromal cells were cultured in sheep on a perforator vessel of the musculus latissimus dorsi over a 6-month period. Histological and histomorphometric analyses revealed that scaffolds loaded with cancellous bone were superior at promoting heterotopic bone formation and ceramic degradation, with autogenous bone and bone marrow aspirate concentrate inducing in vivo formation of vital bone tissue. These results confirm that autologous bone constitutes the preferred source of osteoinductive and osteogenic material that can reliably induce heterotopic bone formation in vivo.

Secondary reconstruction for mandibular osteoradionecrosis defect with fibula osteomyocutaneous flap flowthrough from radial forearm flap using stereolithographic 3-dimensional printing modeling technology

Osteoradionecrosis (ORN) is one of the most serious complications of oral and nasopharyngeal malignant neoplasms after radiotherapy. The incidence of mandibular ORN is significantly higher than that of maxilla. A radical surgical intervention such as mandibulectomy for advanced ORN is appropriate and effective to relieve pain and control infection. However, recovery of functionality and aesthetics is usually not the primary purpose of the one-stage radical surgery. Some patients often need a 2-stage operation owing to the bone defect, scar contracture, or recurrence. Although free flap has been proven as a reliable way to repair the complex maxillofacial defects, it is still a great challenge for surgeons to reconstruct the secondary complex mandibular ORN defects. Here, we report a case of secondary composite mandibular ORN reconstruction using the preoperative 3-dimensional biomodel planning and flowthrough radial forearm flap for free fibula osteocutaneous flap.

Outcomes of microvascular free flap reconstruction for mandibular osteoradionecrosis: A systematic review

INTRODUCTION

Osteoradionecrosis of the mandible is a devastating complication of radiotherapy in patients with head and neck cancer. Many cases present at a late stage, from months to years following completion of radiation therapy. When medical treatment fails, surgery may be required with a variety of free flaps available for microvascular reconstructive techniques.

OBJECTIVE

To conduct a systematic review of the literature investigating the outcomes of free flap reconstruction of the jaw in mandibular osteoradionecrosis and determine the failure rates of different flap tissue.

METHODS

A systematic literature search was performed using Medline (Ovid) Pubmed and Embase databases and Google Scholar. Primary outcome measures were flap failures and complications, with donor site complications representing the secondary outcome measure. Analysis of pooled outcomes was undertaken for different flaps.

RESULTS

333 articles were identified and 15 articles met the final inclusion criteria, detailing 368 primary free tissue flap transfers. There was a flap failure rate of 9.8%. There were 146 post-operative complications (39.7%), the most common being fistula formation (8.4%), hardware plate exposure (7.1%) and flap wound infections (6.5%).

CONCLUSION

The fibula is the workhorse free flap for reconstruction in mandibular osteoradionecrosis. Evidence to date is largely limited with the need for larger powered multi-institutional prospective studies to determine the ideal flap donor tissue and evaluate patient and treatment predictors of free flap outcomes in order to tailor the best patient-based surgical approach for mandibular osteoradionecrosis.

Osteocutaneous free flaps for mandibular reconstruction: systematic review of their frequency of use and a preliminary quality of life comparison

OBJECTIVES

To determine whether the fibula free flap is the most frequently used osteocutaneous flap for mandible reconstruction, and whether it provides quality of life, depression and anxiety advantages.

METHODS

A systematic review of the public Medline database was conducted. Thirteen patients who underwent mandibular reconstruction at our hospital centre completed questionnaires to evaluate quality of life, depression and anxiety outcomes.

RESULTS

The most frequently used free flaps are those of the fibula (n = 982), radial forearm (n = 201), iliac crest (n = 113), subscapular system (n = 50) and rib-serratus (n = 7). In our patient population, there was a trend towards a better quality of life in those with a fibula free flap. However, patients in this group were significantly younger than patients with other flap types (p = 0.025). Patients with a subscapular system free flap were more depressed (p = 0.031); however, they had large through-and-through defects.

CONCLUSION

The flap used most frequently in the literature is the fibula free flap. Comparative quality of life data are lacking, and homogeneous populations should be used to reach significant conclusions.

Perioperative findings and complications of non-vascularised iliac crest graft harvest: The experience of a Nigerian tertiary hospital

Background:

The reconstruction of a mandibular defect remains a significant challenge to the reconstructive surgeon. In developing countries like Nigeria, the required facilities and expertise for vascularised graft surgery are not readily available, thus mandibular defects are commonly reconstructed with non-vascularised bone grafts. The aim of this study is to describe the experience with the reconstruction of mandibular defects using non-vascularised iliac crest bone grafts (NVICBG) at a Nigerian tertiary hospital.

Patients and Methods:

This was a descriptive longitudinal study in which data was prospectively collected from patients who had mandibular reconstruction secondary to benign lesions using NVICBG at the University College Hospital, Ibadan, over a 24-month period. Information recorded included demography, cause of mandibular defect, type of mandibular resection, span of defect, peri-operative data, recipient site complications and donor site complications. Patient satisfaction with facial aesthetic outcome was assessed with the use of visual analogue scale score.

Results:

Twenty patients had mandibular resection and immediate reconstruction with NVICBG. The mean age was 31.61 (+/−11.05) years. Mean span of the defects was 10.65 (+/−2.88) cm. At the recipient site, two patients had extra-oral wound dehiscence and two patients had intra-oral wound dehiscence of which one patient had loss of the graft. Donor site complications noted were seromas and wound dehiscence. Eighteen patients had paraesthesia of the lateral femoral cutaneous nerve. All patients had temporary abnormal gait. The mean duration of abnormal gait was 2.11 weeks (SD +/−0.74). Majority of the patients were satisfied with the aesthetic outcome.

Conclusion:

NVICBG, though limited in its versatility has satisfactory aesthetic outcome with relatively few complications. It appears that this method of reconstruction can be used even for large mandibular defects contrary to perceptions of many reconstructive surgeons.

Autologous Ilium Grafts: Long-Term Results on Immediate or Staged Functional Rehabilitation of Mandibular Segmental Defects Using Dental Implants after Tumor Resection

BACKGROUND

It is a challenge for clinicians to restore oral function in patients with segmental defects of the mandible because of tumor extirpation. Dental implant therapy following vascularized autologous ilium grafts is an effective method to restore oral function in patients with mandibular segmental defects.

PURPOSE

The aim of this retrospective study was to investigate the long-term clinical outcomes of ilium grafts combined with immediate or staged mandibular dental implant therapy to restore craniofacial defects resulting from tumor resection.

MATERIALS AND METHODS

Over a 5-year period (2000-2004), 32 patients who underwent mandibular segmental resection for tumors were treated with vascularized ilium grafts to augment bone volume. Seventeen patients received phase I therapy (immediate placement of implants), and 15 patients underwent phase II therapy (delayed placement of implants). A total of 110 dental implants were placed in these patients for mandibular restoration of the defective areas. Information regarding implant success and survival rates, marginal bone loss, soft tissue inflammation, complications of prosthesis, and patient satisfaction for the 8 to 12 years following oral reconstruction was obtained from patient records.

RESULTS

Although there was mild evidence of bone graft resorption, the vascularized autogenous ilium bone grafts were successful in all patients. The cumulative patient survival and success rate of the implants were 96.4% and 91.8%, respectively. The mean peri-implant bone resorption ranged from 1.0 to 1.2 mm over the 8- to 12-year follow-up period. The annual mean number of complications/repairs was from 0.11 to 0.07 per patient during the 8- to 12-year follow-up. Over 80% of the patients were fully satisfied with their restoration of oral function.

CONCLUSIONS

This study demonstrates that reconstruction of mandibular segmental defects because of resection of mandibular tumors using dental implants therapy combined with vascularized autogenous ilium grafts is an effective method to restore oral function.

Tissue-engineered mandibular bone reconstruction for continuity defects: a systematic approach to the literature

BACKGROUND

Despite significant surgical advances over the last decades, segmental mandibular bone repair remains a challenge. In light of this, tissue engineering might offer a next step in the evolution of mandibular reconstruction.

PURPOSE

The purpose of the present report was to (1) systematically review preclinical in vivo as well as clinical literature regarding bone tissue engineering for mandibular continuity defects, and (2) to analyze their effectiveness.

MATERIALS AND METHODS

An electronic search in the databases of the National Library of Medicine and ISI Web of Knowledge was carried out. Only publications in English were considered, and the search was broadened to animals and humans. Furthermore, the reference lists of related review articles and publications selected for inclusion in this review were systematically screened. Results of histology data and amount of bone bridging were chosen as primary outcome variables. However, for human reports, clinical radiographic evidence was accepted for defined primary outcome variable. The biomechanical properties, scaffold degradation, and clinical wound healing were selected as co-outcome variables.

RESULTS

The electronic search in the databases of the National Library of Medicine and ISI Web of Knowledge resulted in the identification of 6727 and 5017 titles, respectively. Thereafter, title assessment and hand search resulted in 128 abstracts, 101 full-text articles, and 29 scientific papers reporting on animal experiments as well as 11 papers presenting human data on the subject of tissue-engineered reconstruction of mandibular continuity defects that could be included in the present review.

CONCLUSIONS

It was concluded that (1) published preclinical in vivo as well as clinical data are limited, and (2) tissue-engineered approaches demonstrate some clinical potential as an alternative to autogenous bone grafting.

Cholesteryl group- and acryloyl group-bearing pullulan nanogel to deliver BMP2 and FGF18 for bone tissue engineering

To create a drug delivery system that allows the controlled release of proteins, such as growth factors, over a long-term period, cholesteryl group- and acryloyl group-bearing pullulan (CHPOA) nanogels were aggregated to form fast-degradable hydrogels (CHPOA/hydrogels) by cross-linking with thiol-bearing polyethylene glycol. The gold standard of clinical bone reconstruction therapy with a physiologically active material is treatment with recombinant human bone morphogenetic protein 2 (BMP2); however, this approach has limitations, such as inflammation, poor cost-efficiency, and varying interindividual susceptibility. In this study, two distinct growth factors, BMP2 and recombinant human fibroblast growth factor 18 (FGF18), were applied to a critical-size skull bone defect for bone repair by the CHPOA/hydrogel system. The CHPOA-FGF18/hydrogel displayed identical results to the control CHPOA-PBS/hydrogel, and the CHPOA-BMP2/hydrogel treatment imperfectly induced bone repair. By contrast, the CHPOA-FGF18 + BMP2/hydrogel treatment strongly enhanced and stabilized the BMP2-dependent bone repair, inducing osteoprogenitor cell infiltration inside and around the hydrogel. This report indicates that the CHPOA/hydrogel system can successfully deliver two different proteins to the bone defect to induce effective bone repair. The combination of the CHPOA/hydrogel system with the growth factors FGF18 and BMP2 might be a step towards efficient bone tissue engineering.

Swallowing dysfunction in head and neck cancer patients treated by radiotherapy: review and recommendations of the supportive task group of the Italian Association of Radiation Oncology

PURPOSE

Dysphagia is a debilitating complication in head and neck cancer patients (HNCPs) that may cause a high mortality rate for aspiration pneumonia. The aims of this paper were to summarize the normal swallowing mechanism focusing on its anatomo-physiology, to review the relevant literature in order to identify the main causes of dysphagia in HNCPs and to develop recommendations to be adopted for radiation oncology patients. The chemotherapy and surgery considerations on this topic were reported in recommendations only when they were supposed to increase the adverse effects of radiotherapy on dysphagia.

MATERIALS AND METHODS

The review of literature was focused on studies reporting dysphagia as a pre-treatment evaluation and as cancer and cancer therapy related side-effects, respectively. Relevant literature through the primary literature search and by articles identified in references was considered. The members of the group discussed the results and elaborated recommendations according to the Oxford CRBM levels of evidence and recommendations. The recommendations were revised by external Radiation Oncology, Ear Nose and Throat (ENT), Medical Oncology and Speech Language Pathology (SLP) experts.

RESULTS

Recommendations on pre-treatment assessment and on patients submitted to radiotherapy were given. The effects of concurrent therapies (i.e. surgery or chemotherapy) were taken into account.

CONCLUSIONS

In HNCPs treatment, disease control has to be considered in tandem with functional impact on swallowing function. SLPs should be included in a multidisciplinary approach to head and neck cancer.

Pre-operative planning for mandibular reconstruction - a full digital planning workflow resulting in a patient specific reconstruction

Objectives

Reconstruction of large mandiblular defects following ablative oncologic surgery could be done by using vascularized bone transfer or, more often, primarily with simultaneous or delayed bone grafting, using load bearing reconstruction plates. Bending of these reconstruction plates is typically directed along the outer contour of the original mandible. Simultaneously or in a second operation vascularized or non-vascularized bone is fixed to the reconstruction plate. However, the prosthodontic-driven backward planning to ease bony reconstruction of the mandible in terms of dental rehabilitation using implant-retained overdentures might be an eligible solution. The purpose of this work was to develop, establish and clinically evaluate a novel 3D planning procedure for mandibular reconstruction.

Materials and methods

Three patients with tumors involving the mandible, which included squamous cell carcinoma in the floor of the mouth and keratocystic odontogenic tumor, were treated surgically by hemimandibulectomy.

Results

In primary alloplastic mandible reconstruction, shape and size of the reconstruction plate could be predefined and prebent prior to surgery.

Clinical relevance

This study provides modern treatment strategies for mandibular reconstruction.

Current reconstructive techniques following head and neck cancer resection using microvascular surgery

Various techniques have been developed to reconstruct head and neck defects following surgery to restore function and cosmetics. Free tissue transfer using microvascular anastomosis has transformed surgical outcomes and the quality of life for head and neck cancer patients because this technique has made it possible for surgeons to perform more aggressive ablative surgery, but there is room for improvement to achieve a satisfactory survival rate. Reconstruction using the free tissue transfer technique is closely related to cardiovascular surgery because the anastomosis techniques used by head and neck surgeons are based on those of cardiovascular surgeons; thus, suggestions from cardiovascular surgeons might lead to further development of this field. The aim of this article is to present the recent general concepts of reconstruction procedures and our experiences of reconstructive surgeries of the oral cavity, mandible, maxilla, oropharynx and hypopharynx to help cardiovascular surgeons understand the reconstructions and share knowledge among themselves and with neck surgeons to develop future directions in head and neck reconstruction.