Segmental Mandibular Reconstruction Research Articles

Novel Sheep Model to Assess Critical-Sized Bone Regeneration with Periosteum for In Vivo Bioreactors.

Considerable research is being undertaken to develop novel biomaterials-based approaches for surgical reconstruction of bone defects. This extends to three-dimensional (3D) printed materials that provide stable, structural, and functional support in vivo. However, few preclinical models can simulate in vivo human biological conditions for clinically relevant testing. In this study we describe a novel ovine model that allows evaluation of in vivo osteogenesis via contact with bone and/or periosteum interfaced with printed polymer bioreactors loaded with biomaterial bone substitutes. The infraspinous scapular region of 14 Dorset cross sheep was exposed. Vascularized periosteum was elevated either attached to the infraspinatus muscle or separately. In both cases, the periosteum was supplied by the periosteal branch of the circumflex scapular vessels. In eight sheep, a 3D printed 4-chambered polyetheretherketone bioreactor was wrapped circumferentially in vascularized periosteum. In 6 sheep, 12 double-sided 3D printed 2-chambered polyetherketone bioreactors were secured to the underlying bone allowing direct contact with the bone on one side and periosteum on the other. Our model enabled simultaneous testing of up to 24 (12 double-sided) 10 × 10 × 5 mm bioreactors per scapula in the flat contact approach or a single 40 × 10 mm four-chambered bioreactor per scapula using the periosteal wrap. De novo bone growth was evaluated using histological and radiological analysis. Of importance, the experimental model was well tolerated by the animals and provides a versatile approach for comparing the osteogenic potential of cambium on the bone surface and elevated with periosteum. Furthermore, the periosteal flaps were sufficiently large for encasing bioreactors containing biomaterial bone substitutes for applications such as segmental mandibular reconstruction.

Early outcomes of osteofascial versus osteocutaneous fibula free flap mandibular reconstruction.

This study compares early outcomes of osteofascial fibula free flap (OF-FFF) with donor-site primary closure and osteocutaneous (OC) FFF with donor-site skin grafting in segmental mandibular reconstruction. A retrospective chart review of FFF mandibular reconstruction patients (2006-2022) divided into OF-FFF and OC-FFF groups. Clinical data, operative parameters, and early postoperative outcomes (≤ 90 days) were analyzed. The study included 67 patients (39 OF-FFF, 28 OC-FFF). OF-FFF had significantly lower donor-site complications (12.8% vs. 53.6%, p < 0.001) and revision surgeries (7.7% vs. 35.7%, p = 0.004) compared to OC-FFF. Recipient-site (28.2% vs. 25%, p = 0.77) and flap (15.4% vs. 17.9%, p > 0.99) complications were comparable. OF-FFF mandibular reconstruction with donor-site primary closure is a safe and reliable technique associated with superior donor-site and comparable flap and recipient-site outcomes to OC-FFF, thus may be considered as a viable alternative to OC-FFF for selected patients.

In-house virtual surgical planning and guided mandibular reconstruction is less precise, but more economical and time-efficient than commercial procedures.

To compare an in-house and a commercially available surgical planning solution for mandibular reconstruction in terms of postoperative reconstruction accuracy and economic benefit. Twenty-nine consecutive patients with advanced oral squamous cell carcinoma (OSCC) requiring segmental mandibular reconstruction were enrolled. Fifteen patients underwent in-house surgical planning and 14 patients underwent a commercially available planning solution. A morphometric comparison of preoperative and postoperative computed tomography (CT) data sets and a cost-benefit comparison were performed. Volumes of planned and reconstructed bone segments differed significantly for both in-house planning (p = 0.0431) and commercial planning (p < 0.0001). Significant differences in osteotomy angles were demonstrated for in-house planning (p = 0.0391). Commercial planning was superior to in-house planning for total mandibular deviation (p = 0.0217), intersegmental space volumes (p = 0.0035), and lengths (p = 0.0007). No significant difference was found between the two planning solutions in terms of intersegmental ossification and the incidence of wound healing disorders. In-house planning took less time than commercial planning (p < 0.0001). Component manufacturing costs (p < 0.0001) and total cumulative costs (p < 0.0001) were significantly lower for in-house planning. In-house surgical planning is less accurate but has a cost advantage and could be performed in less time.

Biomechanical evaluation of CAD/CAM magnesium miniplates as a fixation strategy for the treatment of segmental mandibular reconstruction with a fibula free flap

Titanium patient-specific (CAD/CAM) plates are frequently used in mandibular reconstruction. However, titanium is a very stiff, non-degradable material which also induces artifacts in the imaging. Although magnesium has been proposed as a potential material alternative, the biomechanical conditions in the reconstructed mandible under magnesium CAD/CAM plate fixation are unknown. This study aimed to evaluate the primary fixation stability and potential of magnesium CAD/CAM miniplates. The biomechanical environment in a one segmental mandibular reconstruction with fibula free flap induced by a combination of a short posterior titanium CAD/CAM reconstruction plate and two anterior CAD/CAM miniplates of titanium and/or magnesium was evaluated, using computer modeling approaches. Output parameters were the strains in the healing regions and the stresses in the plates. Mechanical strains increased locally under magnesium fixation. Two plate-protective constellations for magnesium plates were identified: (1) pairing one magnesium miniplate with a parallel titanium miniplate and (2) pairing anterior magnesium miniplates with a posterior titanium reconstruction plate. Due to their degradability and reduced stiffness in comparison to titanium, magnesium plates could be beneficial for bone healing. Magnesium miniplates can be paired with titanium plates to ensure a non-occurrence of plate failure.

Implant Survival Rate in Mandible Reconstructed with Free Fibula Flaps After Oral Tumors: A Systematic Review and Meta-Analysis.

To assess the implant survival rate in mandibles reconstructed with free fibula flap after oral tumor resection after 1 year of prosthetic loading. A secondary objective was to compare immediate or delayed implant placement protocols in this population. Electronic and manual searches were performed on different databases for controlled and prospective trials that indicated implant survival rate. This systematic review followed PRISMA guidelines. Risk of bias was evaluated using Cochrane Collaboration tools. Meta-analyses heterogeneity source assessment and GRADE evaluation were performed among studies with identical follow-ups. Among 305 primarily selected articles, 109 were eligible after reading the title and abstract, and 8 were included after full-text reading: 2 randomized controlled trials and 6 prospective studies comprising 140 patients and 507 implants. Meta-analyses estimated an overall survival rate of 97% (95% CI: 94% to 99%) after 1 year of prosthetic loading. The survival rate was 98% (95% CI: 94% to 100%) with immediate implantation and 97% (95% CI: 90% to 99%) with delayed implantation. Only 3 studies reported radiotherapy treatment, with no real impact on implant survival rate. Overall, 69% of tumors were benign. Implant placement in vascularized fibula flaps in the mandible is recommended for patients undergoing segmental mandibular reconstruction after tumor resection. Within the limitations of this study, no significant difference in survival rates was found between immediate and delayed implant placement.

Fibula Jaw-during-Admission

Fibula Jaw-in-a-Day (JIAD) is considered the most advanced approach for segmental mandibular defect reconstruction and dental rehabilitation. However, it has limitations and challenges for further pursuit. We propose Fibula Jaw-during-Admission (JDA) as a solution. From 2019 to 2021, six patients received fibula "Jaw-during-Admission." Segmental mandibulectomy, fibula transfer, and immediate dental implantation were performed simultaneously during a single surgery. Intraoral scans were used to fabricate temporary light occlusion contact dental prostheses while on the ward prior to discharge during the first and second week post operation. The prostheses were installed before discharge and changed to permanent ones with normal occlusal contact in the clinic at about six months after X-ray confirmation of bone healing. All six surgeries succeeded. Four patients received palatal muco-periosteal graft after debridement of peri-implant overgrown granulation tissue. Follow-up ranged from 12 to 34 months (average 21.2 months) and revealed good function and appearance in all patients. Fibula JDA is superior to the Fibula JIAD approach for simultaneous mandibular reconstruction with fibula and dental rehabilitation. There is no need for postoperative intermaxillary fixation. The surgery can be performed more reliably with less stress. It provides an additional opportunity for dental rehabilitation if initial dental prosthesis installation during JIAD fails. Postreconstruction intraoral scans provide greater precision and more flexibility in milling dental prosthesis which are mapped to the reconstructed mandible during the postoperative period.

Micro-porous PLGA/β-TCP/TPU scaffolds prepared by solvent-based 3D printing for bone tissue engineering purposes.

The 3D printing process of fused deposition modelling is an attractive fabrication approach to create tissue-engineered bone substitutes to regenerate large mandibular bone defects, but often lacks desired surface porosity for enhanced protein adsorption and cell adhesion. Solvent-based printing leads to the spontaneous formation of micropores on the scaffold's surface upon solvent removal, without the need for further post processing. Our aim is to create and characterize porous scaffolds using a new formulation composed of mechanically stable poly(lactic-co-glycol acid) and osteoconductive β-tricalcium phosphate with and without the addition of elastic thermoplastic polyurethane prepared by solvent-based 3D-printing technique. Large-scale regenerative scaffolds can be 3D-printed with adequate fidelity and show porosity at multiple levels analysed via micro-computer tomography, scanning electron microscopy and N2 sorption. Superior mechanical properties compared to a commercially available calcium phosphate ink are demonstrated in compression and screw pull out tests. Biological assessments including cell activity assay and live-dead staining prove the scaffold's cytocompatibility. Osteoconductive properties are demonstrated by performing an osteogenic differentiation assay with primary human bone marrow mesenchymal stromal cells. We propose a versatile fabrication process to create porous 3D-printed scaffolds with adequate mechanical stability and osteoconductivity, both important characteristics for segmental mandibular bone reconstruction.

Hydrogel: A Potential Material for Bone Tissue Engineering Repairing the Segmental Mandibular Defect.

Free flap surgery is currently the only successful method used by surgeons to reconstruct critical-sized defects of the jaw, and is commonly used in patients who have had bony lesions excised due to oral cancer, trauma, infection or necrosis. However, donor site morbidity remains a significant flaw of this strategy. Various biomaterials have been under investigation in search of a suitable alternative for segmental mandibular defect reconstruction. Hydrogels are group of biomaterials that have shown their potential in various tissue engineering applications, including bone regeneration, both through in vitro and in vivo pre-clinical animal trials. This review discusses different types of hydrogels, their fabrication techniques, 3D printing, their potential for bone regeneration, outcomes, and the limitations of various hydrogels in preclinical models for bone tissue engineering. This review also proposes a modified technique utilizing the potential of hydrogels combined with scaffolds and cells for efficient reconstruction of mandibular segmental defects.

An Artificial Intelligence-Based Cosmesis Evaluation for Temporomandibular Joint Reconstruction.

Management of the temporomandibular joint (TMJ) following condylar resection remains challenging in the field of mandibular reconstruction. A simple reconstruction of the TMJ with a contoured end of a fibular graft placed into the joint space is a potential option, but its efficacy is unknown partly because there are only few objective assessment systems for aesthetic outcome. This study aimed to develop an artificial intelligence (AI)-based aesthetic outcome evaluation system for the simple TMJ reconstruction method and evaluate its functional outcomes. Patients who underwent segmental mandibular resection and reconstruction with fibular flaps at our institution between 2011 and 2020 were retrospectively reviewed. The mandibular asymmetry value was introduced as a primary aesthetic outcome measure, calculated for each patient's photograph using facial recognition AI. The outcomes of the simple TMJ reconstruction method were compared with those of cases in which the native condyle was preserved. Ten patients underwent condylar resection followed by simple TMJ reconstruction, while the native condyle was preserved in 18 patients. No significant difference was observed in the postoperative mandibular asymmetry value between the two treatment groups. No significant differences were found in the functional outcomes of deglutition and speech. The AI-based asymmetry evaluation system was useful as an aesthetic outcome measure in mandibular reconstruction. Simple TMJ reconstruction with a fibular end seemed to be a promising option, as there were no significant differences in both aesthetic and functional outcomes between this method and those cases in which the native condyle was preserved. Laryngoscope, 133:841-848, 2023.

Segmental mandibular reconstruction in patients with poor lower extremity perfusion, vessel-depleted necks and/or profound medical frailty.

Options for segmental mandibular reconstruction in patients poorly suited to undergo fibula free flap (FFF). Although FFF is the current 'gold standard' for segmental mandibular reconstruction, other reconstructive options must be considered when FFF is contraindicated or disfavoured and/or patient frailty precludes a lengthy anaesthetic. In addition to various nonvascularized and soft tissue only reconstructions, excellent osseous free flap alternatives for functional segmental mandibular reconstruction may be employed. The subscapular system free flaps (SSSFF) may be ideal in frail and/or elderly patients, as SSSFF allows for early mobility and does not alter gait. In extensive and/or symphyseal defects, functional mandibular reconstruction in lieu of a free flap is extremely limited. Pedicled segmental mandibular reconstructions remain reasonable options, but limited contemporary literature highlights unpredictable bone graft perfusion and poor long-term functional outcomes. There are several excellent free flap alternatives to FFF in segmental mandibular reconstruction, assuming adequate cervical recipient vessels are present. On the basis of the current literature, the optimal mandibular reconstruction for the medically frail, elderly and/or patients with extreme vessel-depleted necks is limited and debatable. In qualifying (i.e. limited, lateral) defects, soft tissue only reconstructions should be strongly considered when osseous free flaps are unavailable.

Safety and efficacy of secondary mandibular reconstruction using a free osteo-cutaneous fibula flap after segmental mandibular resection: a retrospective case\u2013control study

BackgroundFree osteocutaneous fibula flap (FFF) is currently considered the best option for segmental mandibular reconstruction; however, there are only a few reports comparing secondary with primary reconstructions using FFF. This study aimed to evaluate the safety and efficacy of secondary mandibular reconstruction using FFF when compared with primary mandibular reconstruction.MethodsFrom October 2018 to February 2020, patients who underwent mandibular reconstruction using FFF after segmental mandibulectomy were retrospectively reviewed. The size and location of the mandibular defect, the segment length and number of osteotomies in the fibula, types of the mandibular plating system, kinds and laterality of the recipient vessels were recorded from the surgical notes. Flap survival, duration of nasogastric tube use, and implant installation after reconstruction were recorded as postoperative evaluation indices.ResultsTwelve patients underwent mandibular reconstruction using FFF during the study period. There were no significant differences in demographic characteristics other than body mass index between the primary (n = 8) and secondary (n = 4) reconstruction groups. No significant differences were observed in the size and location of defects, the segment length and number of osteotomies in the fibula, and the types of mandibular plating system. There was no significant difference in the kinds of recipient vessels; however, the laterality of recipient vessels was ipsilateral in all cases of primary reconstructions and contralateral in all cases of secondary reconstructions. Three out of eight patients with primary FFF reconstruction developed partial flap necrosis. Four patients in the secondary FFF reconstruction group achieved complete flap survival. The duration of use of the nasogastric tube and implant installation after reconstruction was comparable between the two groups.ConclusionSafe and effective secondary mandibular reconstruction can be performed in this clinical case study using FFF.

Induced Membranes for Segmental Mandibular Reconstruction: Case Series and Technique Review

This article describes the induced membrane technique (IMT) and presents 10 cases in which the technique was applied for segmental mandibular reconstruction. Ten patients requiring segmental mandibular resection were reconstructed using the staged IMT. Mandibular resection, placement of a reconstruction plate and polymethylmethacrylate spacer, was performed. At the second procedure, the spacer was removed through a small incision and particulate autograft from the ilium was placed, in some cases with bone morphogenic protein. Nine of the 10 patients achieved bony continuity with the IMT. Spacers were designed to optimize mandibular form and future implant-based restoration. All patients have either had implants placed or have adequate bone for implant placement. The average hospital length of stay for both surgeries combined was 3.1 nights. The IMT can be successfully used to reconstruct segmental mandibular defects, allowing surgeons to create a neomandible with optimal form both for facial contour and for dental implant-based reconstruction.

Clinical evaluation of an automated virtual surgical planning platform for mandibular reconstruction.

Virtual surgical planning (VSP), via commercial services or developed in-house, has been applied to facilitate head and neck reconstruction. We evaluate a custom, automated planning software. Prospectively, VSP of 25 consecutive patients undergoing segmental mandibular reconstruction was performed. Postoperative CT was used to assess structural accuracy of VSP. Operative time, length of stay, and complication rate of the prospective cohort were compared with those of 25 consecutive retrospective historical cases. The deviations between the plan and execution in mandibular width, projection, and volumetric overlap were 2.32 ± 3.91, 2.39 ± 1.72, and 0.59 ± 0.51 mm respectively. Compared with historical data, there was a significant reduction in operative time and length of stay, and no significant difference in complication rates. This is the largest prospective series evaluating an in-house VSP workflow for mandibular reconstruction and the first clinical evaluation of an automated planning platform.

Segmental Mandibular Reconstruction Using Tissue Engineering Strategies: A Systematic Review of Individual Patient Data.

The aim of the systematic review was to analyze the current clinical evidence concerning the use of tissue engineering as a treatment strategy for reconstruction of segmental defects of the mandible and their clinical outcomes using individual patient data. A systematic review of the literature was conducted using PubMed and Cochrane Library on May 21, 2019. The eligibility criteria included patients in whom segmental mandibular reconstruction was carried out using tissue engineering as the primary treatment strategy. After screening and checking for eligibility, individual patient data were extracted to the extent it was available. Data extraction included the type of tissue engineering strategy, demographics, and indication for treatment, and outcomes included clinical and radiographic outcome measures, vitality of engineered bone, dental rehabilitation, and patient-reported outcome measures and complications. Out of a total of 408 articles identified, 44 articles reporting on 285 patients were included, of which 179 patients fulfilled the inclusion criteria. The different tissue engineering treatment strategies could be broadly classified into 5 groups: "prefabrication," "cell culture," "bone morphogenetic protein (BMP) without autografts," "BMP with autografts," and "scaffolds containing autografts." Most included studies were case reports or case series. A wide variety of components were used as scaffolds, cells, and biological substances. There was not a single outcome measure that was both objective and consistently reported, although most studies reported successful outcome. A wide variety of tissue engineering strategies were used for segmental mandibular reconstruction that could be classified into 5 groups. Due to the low number of treated patients, lack of standardized and consistent reporting outcomes, lack of comparative studies, and low evidence of reported literature, there is insufficient evidence to recommend any particular tissue engineering strategy.

Registry to Collect Data on Patients Undergoing Segmental Mandibular Defect Reconstruction Following Oral Squamous Cell Carcinoma Resection

Registry to Collect Data on Patients Undergoing Segmental Mandibular Defect Reconstruction Following Oral Squamous Cell Carcinoma Resection

Digital Design, Analysis and 3D Printing of Prosthesis Scaffolds for Mandibular Reconstruction

Segmental mandibular reconstruction has been a challenge for medical practitioners, despite significant advances in medical technology. There is a recent trend in relation to customized implants, made up of porous structures. These lightweight prosthesis scaffolds present a new direction in the evolution of mandibular restoration. Indeed, the design and properties of porous implants for mandibular reconstruction should be able to recover the anatomy and contour of the missing region as well as restore the functions, including mastication, swallowing, etc. In this work, two different designs for customized prosthesis scaffold have been assessed for mandibular continuity. These designs have been evaluated for functional and aesthetic aspects along with effective osseointegration. The two designs classified as top and bottom porous plate and inner porous plate were designed and realized through the integration of imaging technology (computer tomography), processing software and additive manufacturing (Electron Beam Melting). In addition, the proposed designs for prosthesis scaffolds were analyzed for their biomechanical properties, structural integrity, fitting accuracy and heaviness. The simulation of biomechanical activity revealed that the scaffold with top and bottom porous plate design inherited lower Von Mises stress (214.77 MPa) as compared to scaffold design with inner porous plate design (360.22 MPa). Moreover, the top and bottom porous plate design resulted in a better fit with an average deviation of 0.8274 mm and its structure was more efficiently interconnected through the network of channels without any cracks or powder material. Verily, this study has demonstrated the feasibility and effectiveness of the customized porous titanium implants in mandibular reconstruction. Notice that the design and formation of the porous implant play a crucial role in restoring the desired mandibular performance.

Autogenous non-vascularized bone graft in segmental mandibular reconstruction after a gunshot

Autogenous non-vascularized bone graft in segmental mandibular reconstruction after a gunshot

Induced membranes for segmental mandibular reconstruction: technique review and case series

Induced membranes for segmental mandibular reconstruction: technique review and case series

State of the Art Simultaneous Bilateral Segmental Mandibular Reconstruction using a Single Fibula Transplant: Discussion of the Surgical Steps

During last 22 years the different reports have shown successful using of vascularized single fibular transplant for a simultaneous bilateral segmental mandibular reconstruction. The surgeries were performed in cases of bilateral mandibular defects of different origin: 1) bilateral infected pseudoarthrosis, 2) bilateral squamous cell carcinoma of the mandible, 3) bilateral ossifying fibroma, 4) osteoradionecrosis that caused mandibular defects, and 5) traumatic mandibular defects. We present a case of a 60-year-old patient who was referred to our clinic with osteoradionecrosis of bilateral mandible, which was reconstructed using a single fibula flap. A 6-month follow-up images are presented.

Clinical experience with a novel structure designed bridging plate system for segmental mandibular reconstruction: The TriLock bridging plate

The innovative TriLock Bridging Plate System (Medartis AG, Switzerland) was developed to reduce common complications related to conventional mandibular reconstruction plates. The novelties regarding the plating system concern the cross-strut structure in the centerpiece, the bendable side elements and the reduction of the plate's thickness to 2.0 mm 4 different models are available, which cover lateral and central segmental mandibular defects. The plating system has only been introduced at selected maxillofacial units so far and clinical assessment is still lacking. Thus, the aim of the study was to analyze the novel Bridging Plate system in terms of its clinical applicability, rate of trimming and postoperative outcomes in a first investigation over 6 months. The study includes 25 patients with segmental mandibular resection, who underwent reconstruction with TriLock Bridging Plates. According to the assessment parameters, excellent clinical applicability was stated in 48%. The overall trimming rate was found to be 88%. Mostly adaptions to the distal bendable elements of lateral plates were performed. The occurrence of postoperative complications was 16%. Plate fracture occurred in 4%. With reference to the results, the novel plating system represents a viable method for segmental mandibular reconstruction, however, further evaluation is needed, for a more detailed analyzation.