Reconstruction Of Mandibular Defects Research Articles

Augmented reality guided in reconstruction of mandibular defect with fibular flap: A cadaver study

BackgroundAugmented reality (AR) navigation has been developed in recent years and can overcome some limitations of existing technologies. This study aimed to investigate a novel method of fibula free flap (FFF) osteotomy based on AR technology through a cadaver study. MethodsOne mandible, seven fibulas, and seven lower limb specimens underwent computed tomography (CT) examination. We used the professional software Proplan CMF 3.0 to design a defective mandible model and created fourteen virtual reconstruction plans using the fibulas and lower limb specimens. The AR-based intraoperative guidance software prototype was developed using the Unity Real-Time Development Platform, and virtual plans were transferred into this software prototype. We used AR-based surgical navigation to guide the FFF osteotomy and used these fibular segments to reconstruct the defective mandible model. After reconstruction, all segments were scanned by CT. Osteotomy accuracy was evaluated by measuring the length and angular deviation between the virtual plan and the final result. The reconstruction precision was reflected by the volume overlap rate and average surface distance between the planned and obtained reconstruction. ResultsThe length difference, angular deviation, volume overlap rate and average surface distance of the in vitro group were 1.03±0.68 mm, 5.04±2.61°, 95.35±1.81%, and 1.02±0.27 mm, respectively. Those of the in vivo group were 1.18±0.84 mm, 5.45±1.47°, 95.31±2.09%, and 1.22±0.12 mm. ConclusionsDue to the ideal result of cadaver experiments, an AR-based FFF osteotomy guided system may become a novel approach to assist FFF osteotomy for the reconstruction of defective mandibles.

Dual Application of Patient-Specific Occlusion-Based Positioning Guide and Fibular Cutting Guide for Accurate Reconstruction of Segmental Mandibular Defect.

In this study, the authors introduced a dual application of patient-specific occlusion-based positioning guide and fibular cutting guide to obtain ideal occlusal relationship and mandibular contour in patients undergoing mandibular reconstruction. A retrospective review was performed in 21 patients who underwent mandibular reconstruction with a fibular osteocutaneous free flap. Using computed tomography and intraoral scanning data, fibular cutting guide and occlusion-based positioning guide were simulated in a modeling software and 3-dimensionally printed. Both guides were applied in 9 patients, defined as dual guide group, while the fibular cutting guide was solely used in the remaining patients, defined as single guide group. Functional outcomes including occlusion status, trismus, presence of osseointegrated implant were assessed at 1-year postoperative period. To evaluate the accuracy of the reconstruction, the discrepancy between the planned simulation and actual surgical result was quantified by measuring mandibular deviation angle and volume conformity. Regarding the functional outcomes, all patients in dual guide group showed satisfactory occlusion and intact oral capacity at postoperative 1-year assessment, while 3 patients in single guide group had prolonged malocclusion. The dual guide group showed significantly decreased deviation angle in coronal (right side, 2.93°±1.98° vs. 7.02°±2.81°, P =0.003) and axial plane (right side, 3.20°±2.04° vs. 7.63°±3.40°, P =0.006). The mean volume conformity between the simulation and actual fibular object was significantly higher in the dual guide group (75.27%±6.12% vs. 59.06%±8.57%, P =0.001). In conclusion, the use of occlusion-based positioning guide combined with the fibular cutting guide can enhance the accuracy of mandible reconstruction and functional outcomes.

Reconstruction of Dentomaxillofacial Deformity Secondary to Mandibular Defect Using Concomitant Orthognathic Surgery and Fibula Free Flap.

The reconstruction of mandibular defects may be delayed or compromised for many reasons, especially in pediatric patients. With the growth of the remaining mandible and the maxilla in the malocclusion status, secondary dentomaxillofacial deformity is plausible. To treat the concomitant mandibular defect and secondary dentomaxillofacial deformity, a hierarchical algorithm using orthodontics, orthognathic surgery, and fibula free flap was developed. This retrospective case series included six patients with long-term mandibular defects caused by tumor resection without repair or with compromised costochondral reconstruction. All patients were treated using the same staged protocol, but with minor changes: (1) presurgical orthodontics, (2) virtual surgical planning, (3) fabrication of the guides and splints, (4) sequenced operations, and (5) postoperative care. The sequence of surgery included the Le Fort I osteotomy, mandibular sagittal split ramus osteotomy of the remaining ramus, final occlusion registration, repositioning of the distal segment of the mandible, segmented fibula reconstruction, and finally, the fixation of mandibular sagittal split ramus osteotomy. The operations and wound healing were uneventful in all patients, and no flap failure or severe complications were detected. Also, the patients exhibited no signs of temporomandibular joint ankylosis during the follow-up. The subspinale-nasion-supramental angle was significantly reduced after surgery. A significant improvement was detected in the facial contour symmetry measurements postoperatively. This proposed workflow of concomitant orthognathic surgery and the fibula free flap is effective and reliable for the reconstruction of dentomaxillofacial deformity secondary to the long-term mandibular defect.

Standardized and axially vascularized calcium phosphate-based implants for segmental mandibular defects: A promising proof of concept

The reconstruction of massive segmental mandibular bone defects (SMDs) remains challenging even today; the current gold standard in human clinics being vascularized bone transplantation (VBT). As alternative to this onerous approach, bone tissue engineering strategies have been widely investigated. However, they displayed limited clinical success, particularly in failing to address the essential problem of quick vascularization of the implant. Although routinely used in clinics, the insertion of intrinsic vascularization in bioengineered constructs for the rapid formation of a feeding angiosome remains uncommon.In a clinically relevant model (sheep), a custom calcium phosphate-based bioceramic soaked with autologous bone marrow and perfused by an arteriovenous loop was tested to regenerate a massive SMD and was compared to VBT (clinical standard). Animals did not support well the VBT treatment, and the study was aborted 2 weeks after surgery due to ethical and animal welfare considerations. SMD regeneration was successful with the custom vascularized bone construct. Implants were well osseointegrated and vascularized after only 3 months of implantation and totally entrapped in lamellar bone after 12 months; a healthy yellow bone marrow filled the remaining space. Statement of significanceRegenerative medicine struggles with the generation of large functional bone volume. Among them segmental mandibular defects are particularly challenging to restore. The standard of care, based on bone free flaps, still displays ethical and technical drawbacks (e.g., donor site morbidity).Modern engineering technologies (e.g., 3D printing, digital chain) were combined to relevant surgical techniques to provide a pre-clinical proof of concept, investigating for the benefits of such a strategy in bone-related regenerative field.Results proved that a synthetic-biologics-free approach is able to regenerate a critical size segmental mandibular defect of 15 cm3 in a relevant preclinical model, mimicking real life scenarii of segmental mandibular defect, with a full physiological regeneration of the defect after 12 months.

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.

Preparation of functional poly-(lactic acid-co-glycolic acid)-based guided bone-regeneration membrane and its application in the reconstruction of mandibular defects in rats.

This study aimed to prepare functional composite electrospinning fibrous membranes with the functions of antifibrosis and bacteriostasis, as well as to explore its repair effect on rat jaw defect. Poly-(lactic acid-co-glycolic acid) fibrous membrane loaded with cyclic-arginine-glycine-aspartic acid sequence, ornidazole, and nanohydroxyapatite (n-HA) was prepared by electrospinning as the functional layer (GBRL) for adhering onto defective bone. A barrier layer with the function of supporting and isolating different functional layers was prepared by tape-casting method. Poly(p-dioxanone-co-l-phenylalanine) fiber membrane with the function of inhibiting fibrosis was prepared by electrospinning technology as the antifibrosis layer (AFL). The morphology of the composite membrane was characterized by scanning electron microscopy. The effects of different functional layers on the proliferation of mouse osteoblast precursor cells (MC3T3-E1) and mouse fibroblasts (L929) were studied by cell-proliferation test (CCK-8 method). The inhibitory effect of composite membrane on the proliferation of Porphyromonas gingivalis was studied by bacteriostatic circle test. A rat mandibular-bone defect model was established to study the repair effect of composite fiber membrane on bone-defect tissue. This repair effect was compared with that of collagen oral-repair membrane commonly used in clinics. The GBRL layer could support the proliferation of MC3T3-E1 cells, and the AFL layer could inhibit the proliferation of L929 cells. Composite membranes loaded with ornidazole could inhibit the proliferation of Porphyromonas gingivalis. Various composite membranes can induce the reconstruction of rat jaw defects, among which the composite membranes loaded with ornidazole and n-HA had the best repair effect, which was better than that of collagen oral-repair membrane. The electrospun membrane loaded with ornidazole and n-HA as the composite fiber membrane of GBRL layer had excellent antibacterial and bone-tissue-regeneration activity. The effect was better than that of the commonly used collagen oral-repair membrane. Therefore, this material has great potential to induce bone regeneration for defects caused by periodontal diseases.

Vascularized Fibula TMJ Reconstruction: A Report of Five Cases featuring Computerized Patient-specific Surgical Planning.

Background:Mandibular defects involving the condyle represent a complex reconstructive challenge for restoring proper function of the temporomandibular joint because it requires precise bone graft alignment, or alloplastic materials, for complete restoration of joint function. The use of computerized patient-specific surgical planning (CPSSP) technology can aid in the anatomic reconstruction of mandibular condyle defects with a vascularized free fibula flap without the need for additional adjuncts. The purpose of this study was to analyze clinical and functional outcomes after reconstruction of mandibular condyle defects using only a free fibula graft with the assistance of virtual surgery techniques.Methods:A retrospective review was performed to identify all patients who underwent mandibular reconstruction utilizing CPSSP with only a free fibula flap without any temporomandibular joint adjuncts after a hemimandibulectomy with total condylectomy.Results:From 2018 to 2021, five patients underwent reconstruction of mandibular defects involving the condyle with CPSSP technology and preservation of the native temporomandibular articulating disk. The average age was 62 years (range, 44–73 years). The average follow-up period was 29.2 months (range, 9–46 months). Flap survival was 100% (N = 5). The maximal interincisal opening range for all patients was 22–45 mm with no lateral deviation or subjective joint pain. No patients experienced progressive joint hypomobility or condylar migration.Conclusion:The use of CPSSP technology can aid in the anatomic reconstruction of mandibular condyle defects with a vascularized free fibula flap through precise planning and intraoperative manipulation with optimal functional outcomes.

P-60443372-101 - Modifications of the osteomyocutaneous peroneal artery based combined flap for reconstruction of composite anterior-mandibular defects.

Purpose Reconstruction of composite anterior mandibular defect (CAMD) requires the challenging restoration of oral competence and function. This study aimed to evaluate two novel modifications of the Osteomyocutaneous Peroneal Artery-based Combined (OPAC) flap for CAMD with or without lip preservation. Methods CAMDs reconstructed using either of the modifications in a one-year period from February 2020 were studied. When the entire lower lip-chin unit was resected (lip-resected group) a chimeric, bipaddled OPAC flap was used with a Palmaris Longus sling. The larger, inner skin paddle reconstructed the floor of the mouth, alveolus and lower lip draping itself over the sling, while the chimeric paddle was used for the chin defect. Whenever a viable band of lip mucosa was preserved (lip-preserved group), a single large skin paddle covered the chin defect while the intact Crural septum recreated the oral lining with the residual lip intervening. Patients were prospectively evaluated for oral function, symmetry, flap complications and donor site morbidity at one and six months. Results 19 patients were included (8 lip-preserved;11 lip-resected). Mouth opening (mean-35.1 mm), subjective oral competence and facial symmetry were satisfactory at 6 months. Objective measures of speech, eating and aesthetics significantly improved at 6 months (p<0.01, compared to pre-operative). Complications (graft loss-3, wound dehiscence-2) were managed conservatively. Conclusion These modifications of the OPAC flap for CAMDs have the advantage of a single donor site, satisfactory oral competence, function and facial symmetry. Flap complication and donor-site morbidity are minimal. This is a prudent replacement to the current practice of double-free flaps in the reconstruction algorithm of CAMDs. Reconstruction of composite anterior mandibular defect (CAMD) requires the challenging restoration of oral competence and function. This study aimed to evaluate two novel modifications of the Osteomyocutaneous Peroneal Artery-based Combined (OPAC) flap for CAMD with or without lip preservation. CAMDs reconstructed using either of the modifications in a one-year period from February 2020 were studied. When the entire lower lip-chin unit was resected (lip-resected group) a chimeric, bipaddled OPAC flap was used with a Palmaris Longus sling. The larger, inner skin paddle reconstructed the floor of the mouth, alveolus and lower lip draping itself over the sling, while the chimeric paddle was used for the chin defect. Whenever a viable band of lip mucosa was preserved (lip-preserved group), a single large skin paddle covered the chin defect while the intact Crural septum recreated the oral lining with the residual lip intervening. Patients were prospectively evaluated for oral function, symmetry, flap complications and donor site morbidity at one and six months. 19 patients were included (8 lip-preserved;11 lip-resected). Mouth opening (mean-35.1 mm), subjective oral competence and facial symmetry were satisfactory at 6 months. Objective measures of speech, eating and aesthetics significantly improved at 6 months (p<0.01, compared to pre-operative). Complications (graft loss-3, wound dehiscence-2) were managed conservatively. These modifications of the OPAC flap for CAMDs have the advantage of a single donor site, satisfactory oral competence, function and facial symmetry. Flap complication and donor-site morbidity are minimal. This is a prudent replacement to the current practice of double-free flaps in the reconstruction algorithm of CAMDs.

Osteogenic potential of calcium silicate-doped iron oxide nanoparticles versus calcium silicate for reconstruction of critical-sized mandibular defects: An experimental study in dog model

ObjectiveTo evaluate bioactivity and osteogenic potential of calcium silicate (CS)-doped iron oxide (Fe2O3) nanoparticles versus pure CS in the reconstruction of induced critical-sized mandibular defects. DesignCS-doped Fe2O3 was prepared; morphological and microstructure identification of nanoparticles were made. An in vivo randomised design was developed on 24 adult male dogs where four critical-sized mandibular defects were created in each dog. Bone defects were allocated into control, CS, CS-3% Fe2O3 and CS-10% Fe2O3 group. Dogs were euthanized at 1 and 3 months (12 dog/time) for histopathologic and histomorphometric evaluation. ResultsAt three months, bone formation and maturation were evident where mean ± SD percent of mature bone was 2.66 ± 1.8, 9.9 ± 2.5, 22.9 ± 4.9, and 38.6 ± 8.1 in control, CS, CS-3% Fe2O3, and CS-10% Fe2O3 groups respectively. A high significant (P < 0.001) increase in area percent of mature bone was recorded in CS, CS-3% Fe2O3, and CS- 10% Fe2O3 groups compared to control group (73%, 88% and 93.3% respectively). Significant increase (P < 0.001) in area of mature bone was recorded in CS-3% Fe2O3 and CS-10% Fe2O3 groups compared to CS group. A significant increase (P < 0.001) in area of mature bone formation was detected in CS-10% Fe2O3 group compared to other groups. ConclusionCS-doped Fe2O3 has good osteoconductive, biocompatible properties with promoted bone regeneration. Fe2O3 has synergistic effect in combination with CS to promote bone formation. Increasing concentration of Fe2O3 nanoparticles resulted in improved osteogenesis and maturation. Results suggests that the novel CS-Fe2O3 alloplasts could be used for reconstruction of critical-sized bone defects.

Accurate Reconstruction of Mandibular Defects With Vascularized Bone Flaps Through Utilization of Mandible Space-Retention Guides.

Comprehensive evaluation of the effects of using computer-aided design and space retention guide technology to reconstruct mandibular defects using vascularized autogenous bone flaps. This study included 8 patients who received autogenous bone flaps (2 cases of vascularized fibula flaps and 6 cases of vascularized iliac flaps) for mandibular defect reconstruction at Peking University School and Hospital of Stomatology, from July 2018 to May 2021. All patients received digital surgery planning, computer aided design/computer aided manufacture, surgical guide technique for the removal of diseased bone segments, as well as vascularized fibular flap/iliac flap reconstruction. Three-dimensional deviations were analyzed after the operation. The mandibular defects of all 8 patients were successfully reconstructed using the vascularized fibular flap/iliac bone flap. There were no serious complications at either the donor site or recipient site during our follow-up. The average three-dimensional deviation of all 8 patients was 1.92 mm, based on comparisons of preoperative design and actual postoperative computed tomography. Utilizing computer aided design/computer aided manufacture, we designed a new mandibular space-retention guide, which can accurately translate the preoperative digital design plan to real-time surgery with satisfactory accuracy and efficacy.

Long-term facial symmetry after pediatric mandibular reconstruction using the vascularized fibula free flap: A photogrammetric analysis

The fibula free flap is the standard of care in the reconstruction of large mandibular defects in pediatric patients, enabling adequate restoration of the facial contour. However, the unpredictable growth potential of the reconstructed mandible could influence the preservation of the initially restored symmetry over time. Being mindful of the importance of facial appearance during developmental stages, this study aimed to evaluate the long-term facial symmetry after mandible reconstruction using this technique in growing patients. A photogrammetric analysis of facial symmetry using the "Asymmetry Index" (AI) was performed from preoperative and postoperative frontal photographs in 17 pediatric patients (9 males and 8 females) who underwent mandibular reconstruction with the vascularized fibula free flap and had a minimum follow-up of 5 years. Comparisons between preoperative and postoperative measurements-as well as postoperative comparisons between condyle-reconstructed and condyle-preserved patients-were conducted. The mean follow-up was 76.9 (± 19.0) months (range, 60-120). The average age at intervention was 9.23 (± 3.8) years. Mean AI was 15.31 (± 1.81) preoperatively and 3.59 (± 0.97) postoperatively. Differences between preoperative and postoperative measurements were statistically significant in all the assessed parameters (p<0.001). Postoperative differences between the condyle-reconstructed and the condyle-preserved groups were not significant (p>0.05). No secondary procedures were required to enhance symmetry in the late postoperative period. Mandibular reconstruction using the vascularized fibula free flap provides adequate restoration of facial symmetry that could be predictably maintained throughout the developmental period in children and adolescents, regardless of the need for condylar reconstruction.

Novel Design and Optimization of Porous Titanium Structure for Mandibular Reconstruction.

A porous material is considered to be a potential material that can be used to repair bone defects. However, the methods of designing of a highly porous structure within the allowable stress range remain to be researched. Therefore, this study was aimed at presenting a method for generating a three-dimensional tetrahedral porous structure characterized by low peak stress and high porosity for the reconstruction of mandibular defects. Firstly, the initial tetrahedral porous structure was fabricated with the strut diameters set to 0.4 mm and a mean cell size of 2.4 mm in the design model space. Following this, the simulation analysis was carried out. Further, a homogenization algorithm was used for homogenizing the stress distribution, increasing porosity, and controlling peak stress of the porous structure by adjusting the strut diameters. The results showed that compared with the initial porous structure, the position of the large stress regions remained unchanged, and the peak stress fluctuated slightly in the mandible and fixation system with the optimized porous structure under two occlusions. The optimized porous structure had a higher porosity and more uniform stress distribution, and the maximum stress was lower than the target stress value. The design and optimization technique of the porous structure presented in this paper can be used to control peak stress, improve porosity, and fabricate a lightweight scaffold, which provides a potential solution for mandibular reconstruction.

A hierarchical vascularized engineered bone inspired by intramembranous ossification for mandibular regeneration

Mandibular defects caused by injuries, tumors, and infections are common and can severely affect mandibular function and the patient’s appearance. However, mandible reconstruction with a mandibular bionic structure remains challenging. Inspired by the process of intramembranous ossification in mandibular development, a hierarchical vascularized engineered bone consisting of angiogenesis and osteogenesis modules has been produced. Moreover, the hierarchical vascular network and bone structure generated by these hierarchical vascularized engineered bone modules match the particular anatomical structure of the mandible. The ultra-tough polyion complex has been used as the basic scaffold for hierarchical vascularized engineered bone for ensuring better reconstruction of mandible function. According to the results of in vivo experiments, the bone regenerated using hierarchical vascularized engineered bone is similar to the natural mandibular bone in terms of morphology and genomics. The sonic hedgehog signaling pathway is specifically activated in hierarchical vascularized engineered bone, indicating that the new bone in hierarchical vascularized engineered bone underwent a process of intramembranous ossification identical to that of mandible development. Thus, hierarchical vascularized engineered bone has a high potential for clinical application in mandibular defect reconstruction. Moreover, the concept based on developmental processes and bionic structures provides an effective strategy for tissue regeneration.

Semi-automated digital workflow to design and evaluate patient-specific mandibular reconstruction implants

The reconstruction of large mandibular defects with optimal aesthetic and functional outcomes remains a major challenge for maxillofacial surgeons. The aim of this study was to design patient-specific mandibular reconstruction implants through a semi-automated digital workflow and to assess the effects of topology optimization on the biomechanical performance of the designed implants. By using the proposed workflow, a fully porous implant (LA-implant) and a topology-optimized implant (TO-implant) both made of Ti–6Al–4V ELI were designed and additively manufactured using selective laser melting. The mechanical performance of the implants was predicted by performing finite element analysis (FEA) and was experimentally assessed by conducting quasi-static and cyclic biomechanical tests. Digital image correlation (DIC) was used to validate the FE model by comparing the principal strains predicted by the FEM model with the measured distribution of the same type of strain. The numerical predictions were in good agreement with the DIC measurements and the predicted locations of specimen failure matched the actual ones. No statistically significant differences (p < 0.05) in the mean stiffness, mean ultimate load, or mean ultimate displacement were detected between the LA- and TO-implant groups. No implant failures were observed during quasi-static or cyclic testing under masticatory loads that were substantially higher (>1000 N) than the average maximum biting force of healthy individuals. Given its relatively lower weight (16.5%), higher porosity (17.4%), and much shorter design time (633.3%), the LA-implant is preferred for clinical application. This study clearly demonstrates the capability of the proposed workflow to develop patient-specific implants with high precision and superior mechanical performance, which will greatly facilitate cost- and time-effective pre-surgical planning and is expected to improve the surgical outcome.

Extended Total Temporomandibular Joint Replacement - A Feasible Option for Functional and Aesthetic Reconstruction of Mandibular Defects Involving the Temporomandibular Joint.

Study design: Retrospective case series. Objective: Alloplastic temporomandibular joint replacement has been established as a standard technique for end- stage temporomandibular (TMJ) pathologies. Joint replacement when there are extensive mandibular defects remains a challenging clinical problem. Custom-made extended temporomandibular joint replacement is a feasible option but there is limited information about this emerging technique. Methods: Included were all patients undergoing extended TMJ-replacements (TMJe), all operatrions were carried out by the senior author. Surgical technique was either single stage or two stage protocol. Surgical details and pitfalls and outcome of more than 2 years follow-up with reference to thirteen including twelve patients were recorded. Results: The most common diagnosis was ameloblastoma of the mandibular ramus. Single stage or two stagge regime were carried out depending on resection requirements and involvement of teeth. Improved mouth opening of more than 30mm was achieved in 10 of 12 patients. One patient with previous TMJ replacement reported temporary weakness of the facial nerve, which resolved after 10 months. Conclusions: The authors suggest a simplified anatomically based single-stage or two-stage regime, with both regimes achieved excellent anatomic reconstruction, facial appearance and function with low surgical morbidity. Custom-made extended temporomandibular joint protheses appear an advanced and reliable solution for reconstruction of combined complex mandibular defects including the temporomandibular joint. If surgical clearance of the pathology can be achieved, a single-stage regime is favoured.

Secondary Mandible Reconstruction with Computer-Assisted-Surgical Simulation and Patient-Specific Pre-Bent Plates: The Algorithm of Virtual Planning and Limitations Revisited

Despite the known advantages of virtual surgical planning and three-dimensional (3D) printing, translation of virtual planning to actual operation is a challenge, especially in secondary mandibular reconstruction. Patients who underwent secondary microvascular mandibular reconstruction were retrospectively reviewed and categorized into three categories as follows: (i) defect not crossing the midline (category I); (ii) defects crossing the midline with availability of previous imaging data (category II) and; (iii) defects crossing the midline with unavailability of previous imaging data (category III). The resulting 3D printed models were used as an effective guide for plate bending during secondary reconstruction surgery. Accuracy of the reconstruction was evaluated by superimposing post-operative images over virtual plan. Out of eleven patients, five were category I, three were category II, and three were category III. The mean linear discrepancy between the planned and post-operative position was measured. A Mann-Whitney U test was conducted to compare mean discrepancy among the groups showed no significant difference between group I and group II (p &gt; 0.05) whereas comparison of groups I and II with group III showed a significant difference (p &lt; 0.01). The proposed algorithm for the generation of defect template for manual plate bending during secondary reconstruction of mandibular defects is valid with acceptable accuracy in various defect configurations.

Real-time intraoperative computed tomography can accurize virtual surgical planning on the double-barrel fibular flap for mandibular reconstruction

Real-time intraoperative computed tomography created the accuracy of less than 1 mm deviation in virtual surgical planning double barrel fibular flap for mandibular reconstruction-the symbiosis of intelligent technology in a digital OR. BackgroundWith the intelligent technology of virtual surgical planning, CAD/CAM, and intraoperative CT(iCT) in a digital OR, the secondary mandibular defect or primary amelobalstoma mandibulectomy can be restored using double barrel fibula and be achieved precision medicine purpose. Material and MethodA series of 7 patients underwent free flap for oral cancers who sustained 5 osteoradionecrosis, 2 segmental mandibular defect, and 2 ameloblastoma. They received 9 double barrel fibula flap and 2 free skin flaptransfers. The fibula flap were reconstructed using a virtual surgical planning including CAD/CAM for simulation 3D model, cutting guides for recipient sites and fibulas osteotomy, and iCT for image fusion in a digital OR. ResultThe mandibular defect was 5–16 cm (average: 9.56 cm), and 2–5 fibular struts for double barrel fibula (average: 3.67 struts) image fusion. One vein graft for artery was required and all 11 flaps were transferred successfully without reexploration. Six patients had intraoperative revision of the fibula and plate to improve the onlay image fusion volume from 74.71 to 82.57%. The postoperative inter-incisor midline deviation was less than 2 mm in 5 patients, and well reduction image in 4 edentulous patients. Five landmarks including bilateral condyles, bilateral gonions, and gnathion demonstrated deviation less than 1 mm in average. ConclusionCAD/CAM can allow a practical virtual surgery to restore mandibular defect reconstruction using a double barrel fibula. The symbiosis of intelligent technology in a digital OR, the iCT can promote the accuracy of mandibular spatialframework and occlusion plain.

Assembly of 3D-printed Ti scaffold and free vascularized fibula using a customized Ti plate for the reconstruction of mandibular defects

Assembly of 3D-printed Ti scaffold and free vascularized fibula using a customized Ti plate for the reconstruction of mandibular defects

Reconstruction of Mandibular Contour Defect Using Patient-Specific Titanium Implant Manufactured by Selective Laser Melting Method.

:The purpose of this study was to evaluate the surgical accuracy and postoperative stability of patient-specific titanium implants (PSTIs) manufactured by the selective laser melting method and applied for mandibular contour reconstruction. For 2 patients who showed asymmetry of the mandibular angle after mandibuloplasty, including angle reduction, reconstructive surgeries of the mandibular contour defects were performed using PSTI. Patient-specific titanium implant was three-dimensional designed using a mirror image similar to the shape of the contralateral side, and 3 screw holes were formed, avoiding the inferior alveolar nerve. Patient-specific titanium implant was applied intraorally, and screw fixation was performed via a transbuccal approach. Surgical accuracy and postoperative stability were evaluated by comparing preoperative three-dimensional design with immediate postoperative computed tomography (CT), and immediate postoperative CT with postoperative 6-month CT, respectively. Both patients were satisfied with the surgical results, and no complications were observed. Surgical accuracy was defined as a mean Hausdorff distance <0.4mm, and postoperative stability was defined as a mean Hausdorff distance <0.3mm. Our results suggest that PSTI by the selective laser melting method for augmentation of the mandibular border is useful as an additional cosmetic surgery.

The Value of Three-Dimensional Modeling on Repositioning and Soft Tissue Filling in Microsurgical Reconstruction of Secondary Mandibular Defects: A Retrospective Study.

PurposeSecondary mandibular defect reconstruction is a challenging operation. It is performed rather rarely, as in most of the cases a primary reconstruction is preferable. Restoration of function and symmetry, in secondary reconstruction of mandibular defects, requires accurate repositioning of segments and appropriate soft tissue filling. The purpose of this study is to estimate the value of three-dimensional (3D) digital modeling to meet the above requirements, in secondary microsurgical reconstruction of mandibular defects.MethodsFive cases of mandibular defects, with various degrees of asymmetry and dysfunction, were restored secondarily, with fibula flaps, after virtual reconstruction on a 3D model derived from their computed tomography, with the utilization of CAD-CAM software. Software reproduced symmetrical 3D models by mirroring the healthy side. Occlusion was restored by fine adjustments on 3D models and finally a reconstruction plate was pre-bent on them, prior to its sterilization for use in surgery. Three out of the five cases received an osteo-cutaneous flap, while in the other two patients, an osseous flap was used. Lower face symmetry, mouth opening, and main patient’s complaints were evaluated pre- and postoperatively to assess the value of the 3D modeling.ResultsAll flaps survived. Hematoma occurred in two patients and was resolved after evacuation. In two patients, a fistula observed, was attributed to screw loosening, and treated after a surgical debridement and screw replacement. Intraoral exposure in the posterior part of the fibula flap was recorded in one patient, possibly from wound dehiscence due to tension of the intraoral tissue, and successfully covered with an ipsilateral nasolabial flap. The resulting symmetry and function were satisfactory in all the patients.ConclusionSecondary mandibular defects are often related with cosmetic disfigurement, misalignment of mandibular segments, and mandibular malfunction. For the correction of mandibular continuity, symmetry, and restoration of function, preoperative 3D modeling may be an important tool, according to our results.