Reconstruction Of Mandibular Defects Research Articles

Application of mixed reality technology in free fibular flap transplantation for repairing mandibular defects

To explore the feasibility and effectiveness of mixed reality technology for localizing perforator vessels in the repair of mandibular defects using free fibular flap. Between June 2020 and June 2023, 12 patients with mandibular defects were repaired with free fibular flap. There were 8 males and 4 females, with an average age of 61 years (range, 35-78 years). There were 9 cases of ameloblastomas and 3 cases of squamous cell carcinomas involving the mandible. The disease duration ranged from 15 days to 2 years (median, 14.2 months). The length of mandibular defects ranged from 5 to 14 cm (mean, 8.5 cm). The area of soft tissue defects ranged from 5 cm×4 cm to 8 cm×6 cm. Preoperative enhanced CT scans of the maxillofacial region and CT angiography of the lower limbs were performed, and the data was used to create three-dimensional models of the mandible and lower limb perforator vessels. During operation, the mixed reality technology was used to overlay the three-dimensional model of perforator vessels onto the body surface for harvesting the free fibular flap. The length of the fibula harvested ranged from 6 to 15 cm, with a mean of 9.5 cm; the size of the flap ranged from 6 cm×5 cm to 10 cm×8 cm. The donor sites were sutured directly in 7 cases and repaired with free skin grafting in 5 cases. Thirty perforator vessels were located by mixed reality technology before operation, with an average of 2.5 vessels per case; the distance between the exit point of the perforator vessels located before operation and the actual exit point ranged from 1 to 4 mm, with a mean of 2.8 mm. All fibular flaps survived; 1 case had necrosis at the distal end of flap, which healed after dressing changes. One donor site had infection, which healed after anti-inflammatory dressing changes; the remaining incisions healed by first intention, and the grafts survived smoothly. All patients were followed up 8-36 months (median, 21 months). The repaired facial appearance was satisfactory, with no flap swelling. Among the patients underwent postoperative radiotherapy, 2 patients had normal bone healing and 1 had delayed healing at 6 months. In free fibular flap reconstruction of mandibular defects, the use of mixed reality technology for perforator vessel localization can achieve three-dimensional visualization, simplify surgical procedures, and reduce errors.

Productizing Nano-Bioactive Glass-Based Bilayer Scaffolds: A Graft for Reconstruction of Mandibular and Femoral Bone Defects.

This investigation aimed to construct a bilayer scaffold integrating alginate and gelatin with nanobioactive glass (BG), recognized for their efficacy in tissue regeneration and drug delivery. Scaffolds, namely, alginate/gelatin (AG), alginate-/actonel gelatin (AGD), alginate actenol/gelatin-45S5 BG (4AGD), and alginate-actonel/gelatin-59S BG (5AGD), were assembled using a cost-effective freeze-drying method, followed by detailed structural investigation via powder X-ray diffraction as well as morphological characterization using field emission scanning electron microscopy (FESEM). FESEM revealed a honeycomb-like morphology with distinct pore sizes for nutrient, oxygen, and drug transport. The scaffolds evidently exhibited hemocompatibility, high porosity, good swelling capacity, and biodegradability. In vitro studies demonstrated sustained drug release, particularly for scaffolds containing actonel. In vivo tests showed that the bilayer scaffold promoted new bone formation, surpassing the control group in bone area increase. The interaction of the scaffold with collagen and released ions improved the osteoblastic function and bone volume fraction. The findings suggest that this bilayer scaffold could be beneficial for treating critical-sized bone defects, especially in the mandibular and femoral regions.

Objective Evaluation of Accuracy of Stereolithographic Models in Reconstruction of Mandibular Defects

Objective Evaluation of Accuracy of Stereolithographic Models in Reconstruction of Mandibular Defects

Early and Late Complications of Mandibulectomy Free Flap Reconstruction: Does the Selective Use of Soft Tissue Only Flaps Reduce Complications?

This study aims to evaluate the factors most associated with early and late complications following microvascular free tissue transfer (MVFTT) after mandibulectomy. A retrospective review of patients undergoing MVFTT after segmental mandibulectomy from September 2016 to February 2021 was performed across a single academic institution. Surgical variables were collected, including the location of the resultant mandibular defect (anterior vs posterior) and flap type (osseous or non-osseous). The primary outcome variables included postoperative complications (early, <90 days; and late, >90 days) and the patients' functional status (return to oral intake). Descriptive statistics, chi-square test, Fischer's exact test, and 2-sample t tests were used to analyze differences among variables. We analyzed a cohort of 114 consecutive patients with mandibular defects, comprising 57 anterior and 57 posterior defects. Bony free flaps with hardware were used to reconstruct 98% of anterior defects compared to 58% of posterior defects (P < .001). All soft tissue only flaps did not utilize any hardware during the reconstruction. Anterior defects demonstrated more late complications requiring additional surgery (30% vs 9%, P = .04). A secondary analysis of posterior mandibular reconstructions compared soft tissue only flaps and bony free flaps with hardware and showed equivalent rates of early (12% vs 13%, P > .99) and late (9% vs 8%, P > .99) complications requiring additional surgery while demonstrating a similar return to full oral competence (55% vs 46%, P = .52) and recovery of a 100% oral diet (67% vs 54%, P = .53). Osseous free tissue transfer for segmental mandibular defects remains the gold standard in reconstruction. In our patient cohort, anterior mandibular defects are associated with greater late (>90 day) complications requiring additional surgery. Comparable outcomes may be achieved with soft tissue only versus osseous free flap reconstruction of posterior mandibular defects.

A Stage-Wise Residual Attention Generation Adversarial Network for Mandibular Defect Repairing and Reconstruction.

Surgical reconstruction of mandibular defects is a clinical routine manner for the rehabilitation of patients with deformities. The mandible plays a crucial role in maintaining the facial contour and ensuring the speech and mastication functions. The repairing and reconstruction of mandible defects is a significant yet challenging task in oral-maxillofacial surgery. Currently, the mainly available methods are traditional digitalized design methods that suffer from substantial artificial operations, limited applicability and high reconstruction error rates. An automated, precise, and individualized method is imperative for maxillofacial surgeons. In this paper, we propose a Stage-wise Residual Attention Generative Adversarial Network (SRA-GAN) for mandibular defect reconstruction. Specifically, we design a stage-wise residual attention mechanism for generator to enhance the extraction capability of mandibular remote spatial information, making it adaptable to various defects. For the discriminator, we propose a multi-field perceptual network, consisting of two parallel discriminators with different perceptual fields, to reduce the cumulative reconstruction errors. Furthermore, we design a self-encoder perceptual loss function to ensure the correctness of mandibular anatomical structures. The experimental results on a novel custom-built mandibular defect dataset demonstrate that our method has a promising prospect in clinical application, achieving the best Dice Similarity Coefficient (DSC) of 94.238% and 95% Hausdorff Distance (HD95) of 4.787.

Osteo-cutaneous microvascular free-flaps are a viable option for reconstructing the temporomandibular joint

BackgroundThere are multiple reconstructive options after mandibular resection and disarticulation of the condyle. The purpose of this study was to assess the clinical outcomes and functionality of osteocutaneous free flaps in the reconstruction of mandibular defects that involve the Temporo-Mandibular Joint (TMJ). MethodsOur study is a retrospective cohort study involving subjects who underwent mandibular resection and needed TMJ reconstruction with vascularized bony-free flaps from February 2016 to June 2018. Data gathered included patient demographics, post-operative function, maximum interincisal opening (MIO), occlusion status, deviation on opening, and TMJ symptoms. Data points collected from postoperative CT imaging included the following: position of the flap in relation to the glenoid fossa and articular eminence, and closest point of contact. ResultsEight out of the nine patients who underwent free flap reconstruction of mandibular defects involving the TMJ qualified for the study. The mean age was 39.7 years old. In all 8 cases, virtual surgical planning (VSP) was used. The mean follow-up time was 18.75 months. The flap success rate was 100%. The mean MIO was 37.37 mm. Six patients resumed their premorbid diet, and one patient developed dysphagia and was peg tube dependent. In seven cases the occlusion was intact and reproducible, one case was without sufficient teeth for occlusion. On imaging, the mean distance from the neo-condyle to the glenoid fossa was 14 mm and to the articular eminence 8.68 mm. The point of closest contact in all cases appeared to be the articular eminence. ConclusionVascularized Osteocutaneous-flaps such as FFFs and DCIA flaps provide a good option for the reconstruction of mandibular defects that involve the TMJ. Ipsilateral deviation on opening does not negatively affect clinical outcomes or function. Placing patients in Maxillomandibular fixation for 4–6 weeks may help to prevent condylar sag and provide stable post-operative occlusion.

Delayed reconstruction of the combat-related mandibular defects with non-vascularized iliac crest grafts: Defining the optimal conditions for a positive outcome in the retrospective study

BackgroundReconstruction of mandibular defects caused by combat injuries is challenging for clinicians due to soft tissue defects and high complication risk. This study evaluated the outcomes of mandibular continuous defects reconstruction with non-vascularized iliac crest graft (NVICG) in patients with combat injuries. Material and methodsPatients with continuous mandibular defects acquired by high-velocity agents, who received NVICG reconstruction with or without microvascular-free soft tissue or regional flaps, were included in the study. The outcome variable was graft loss due to postoperative complications or full (more than 90 %) resorption. The primary predictor variable was soft tissue defect in the recipient area. The secondary predictor variable was the length of the defect. Variables related to patients, defect site, surgery, and other complications were also evaluated. Statistical analysis was performed with the usage of independent sample t-test, Pearson's chi-squared and Fisher's exact tests with a significance level of P < 0.05 ResultsThe study included 24 patients with 27 mandibular defects. Overall, the general success rate of reconstructions was 59.3 %. Soft tissue defects were significantly associated with graft failure and other complications (p < 0.05), which were mostly related to soft tissue defects. The graft success rate was only 14.3 % even in minor soft tissue defects. In turn, in reconstructions with sufficient soft tissue coverage, the graft survived in 75.0 % of the cases. In addition, patients with more delayed reconstruction had significantly fewer graft failures than those with earlier surgery (p < 0.05). No associations were found between defect size and complications. ConclusionThe sufficient soft tissue coverage is essential in the reconstruction of mandibular defects caused by combat injuries. Also, minor soft tissue defects should be covered with soft tissue flaps to avoid complications and graft loss in these specific injuries. Even large defects can be reconstructed with NIVICG if the soft tissue coverage is sufficient.

Comparison of the Outcome of Free Iliac Bone Graft and Vascularized Iliac Bone Graft in Reconstruction of Mandibular Defects: A Systematic Review

Comparison of the Outcome of Free Iliac Bone Graft and Vascularized Iliac Bone Graft in Reconstruction of Mandibular Defects: A Systematic Review

Efficacy of personalized 3D-printed osteotomy guide in maximizing fibular utilization and minimizing graft length for reconstruction of large mandibular defect.

The study addresses the long-standing challenge of insufficient length in vascularized fibular flaps when reconstructing large mandibular defects that require dual-barrel grafts. Employing personalized 3D-printed osteotomy guides, the study aims to optimize fibular utilization and minimize the required graft length. Two reconstruction methods for distal bone defects were compared: a fold-down (FD) group that employed a specialized osteotomy guide for folding down a triangular bone segment, and a traditional double-barrel (DB) group. Metrics for comparison included defect and graft lengths, as well as the graft-to-defect length ratio. Postoperative quality of life was assessed using the University of Washington Quality of Life questionnaire (UW-QoL). Both FD and DB groups achieved successful mandibular reconstruction. Despite larger defects in the FD group (117 ± 31.35mm vs 84 ± 35.34mm, p = 0.028), the used fibula length was not statistically longer in the FD group. The median ratio of graft-to-defect length was also lower in the FD group (1.327 vs 1.629, p = 0.024), suggesting that FD required only 82.47% of the graft length needed in the DB approach. Quality of life scores post-surgery were comparable between the groups. Personalized 3D-printed osteotomy guides enhance fibula graft efficacy for reconstructing larger mandibular defects, necessitating shorter graft lengths while preserving postoperative quality of life. This study confirms the utility of 3D printing technology as an effective and precise tool in orthopedic surgery, particularly for complex reconstructions like large mandibular defects. It suggests a viable alternative that could potentially revolutionize current practices in bone grafting.

Finite element analysis and clinical application of 3D-printed Ti alloy implant for the reconstruction of mandibular defects

BackgroundThe reconstruction of segmental defect of the mandible has always been a challenge. The customized reconstruction plate without a bone graft is also considered a transitional means of rehabilitation and reconstruction in some cases.MethodsThis study evaluated the biomechanical behaviors of customized plates with different structural designs comparing with commercial plates using the finite element method in reconstrution of the lateral mandible defect.ResultsSimulations revealed the stress state in the plate bodies, bone tissues and screws were associated with the width, height, thickness of the plates as well as the distribution of screws. In all of the groups, the system of 16 mm-high, 2.8 mm-thick customized reconstruction plate with 10 screws was considered to be the most ideal design because of the most harmonious biomechanical state. What’s more, the stress shielding effects were not obvious in this experiment. Based on the above findings, we conducted a clinical case analysis to verify the mechanical properties of customized reconstruction and obtained a satisfactory operation result.ConclusionsThe results show that by adjusting the contour parameters of the reconstruction plates, an ideal and reliable customized plate can be manufactured. And the customized 3D-printed Ti alloy implant will be a new way to achieve mandibular reconstruction in patients unable to perform autologous bone graft surgery.Trial registrationThe present trial has been registered with ChiCTR, the registration number is ChiCTR 2,000,038,973 on 11/10/2020.

Computer-aided designed 3D-printed polymeric scaffolds for personalized reconstruction of maxillary and mandibular defects: a proof-of-concept study

PurposeTo investigate the potential reconstruction of complex maxillofacial defects using computer-aided design 3D-printed polymeric scaffolds by defining the production process, simulating the surgical procedure, and explore the feasibility and reproducibility of the whole algorithm.MethodsThis a preclinical study to investigate feasibility, reproducibility and efficacy of the reconstruction algorithm proposed. It encompassed 3 phases: (1) scaffold production (CAD and 3D-printing in polylactic acid); (2) surgical simulation on cadaver heads (navigation-guided osteotomies and scaffold fixation); (3) assessment of reconstruction (bone and occlusal morphological conformance, symmetry, and mechanical stress tests).ResultsSix cadaver heads were dissected. Six types of defects (3 mandibular and 3 maxillary) with different degree of complexity were tested. In all case the reconstruction algorithm could be successfully completed. Bone morphological conformance was optimal while the occlusal one was slightly higher. Mechanical stress tests were good (mean value, 318.6 and 286.4 N for maxillary and mandibular defects, respectively).ConclusionsOur reconstructive algorithm was feasible and reproducible in a preclinical setting. Functional and aesthetic outcomes were satisfactory independently of the complexity of the defect.

Virtual surgical planning for mandibular reconstruction in an abbreviated admission pathway

ObjectivesVirtual Surgical Planning (VSP) creates individualized surgical plans for free flap reconstruction of mandibular defects. Prior studies indicate that VSP can offer cost benefits due to reduced operative time and length of stay (LOS). We assessed the impact of VSP in the context of a validated postoperative abbreviated LOS clinical pathway. MethodsThis study assessed patients undergoing VSP vs conventional fibular free flap reconstruction for mandibular defects (12/2015–10/2020) and their operative time, ischemia time, and LOS were evaluated. ResultsForty-four patients underwent VSP reconstruction, while 52 patients underwent conventional reconstruction for mandibular defects. VSP was associated with significantly lower total operative time (6 h and 57 mins vs 7 h and 54 mins, p = 0.011), but not length of stay or ischemia time. Total OR time was significantly increased with increasing number of segments needed in both the VSP group (p = 0.002) and the conventional group (p = 0.015). ConclusionShorter operative times and LOS have been attributed to the use of VSP in free tissue transfers. It is argued that these reductions offset the added cost of VSP. Our study indicates that there is no cost benefit for VSP utilization due to a significantly reduced operative time with no impact on length of admission in an abbreviated admission clinical pathway following free tissue transfer.

Biomechanical behavior of the three-dimensionally printed surgical plates for mandibular defect reconstruction: a finite element analysis

The aim of the study was to investigate the biomechanical behavior of three-dimensionally (3D)-printed surgical plates used for mandibular defect reconstruction, compare them with conventional surgical plates, and provide experimental evidence for their clinical application. Three-dimensional models were created for the normal mandible and for mandibular body defects reconstructed using free fibula and deep circumflex iliac artery flaps. Three-dimensional finite element models of reconstructed mandibles fixed using 3D-printed and conventional surgical plates were established. Vertical occlusal forces were applied to the remaining teeth and the displacement and Von Mises stress distributions were studied using finite element analysis. The normal and reconstructed mandibles had similar biomechanical behaviors. The displacement distributions for the surgical plates were similar, and the maximum total deformation occurred at the screw hole of the anterior segment of the surgical plates. However, there were differences in the Von Mises stress distributions for the surgical plates. In reconstructed mandibles fixed using 3D-printed surgical plates, the maximum equivalent Von Mises stress occurred at the screw hole of the posterior segment, while in those fixed using conventional surgical plates, the maximum equivalent Von Mises stress was at the screw hole of the anterior segment. In the mandible models reconstructed with the same free flap but fixed with different surgical plates, the plates had similar biomechanical behaviors. The biomechanical behavior of 3D-printed surgical plates was similar to conventional surgical plates, suggesting that 3D-printed surgical plates used to reconstruct mandibular body defects with vascularized autogenous bone grafts could lead to secure and stable fixation.

A preliminary analysis of patient reported outcomes following posterolateral mandible reconstruction: The role of flap type.

The choice of tissue type for free flap reconstruction of posterolateral mandible resections is dependent on patient and defect characteristics. We compared clinical and patient-reported outcomes following reconstruction of these defects with a soft tissue or bony free flap. A retrospective review was performed on patients who underwent posterolateral segmental mandibulectomy with immediate free flap reconstruction at MSKCC from 2006 to 2021. Outcomes of interest were patient-reported outcome measures (PROMs) assessed by FACE-Q surveys and complications at the flap recipient site. Ninety patients received a bony flap and 24 patients received a soft tissue flap. Patients reconstructed with soft tissue flaps had greater rates of composite soft tissue defects (p < 0.0001), condyle resection (p = 0.001), and peripheral vascular disease (p = 0.035). Complication rates were similar between the cohorts (p > 0.05). Bony flaps scored higher on multiple FACE-Q scales: Facial Appearance (p = 0.023) Eating/Drinking (p = 0.029), Smiling (p = 0.012), Speaking (p < 0.001), Swallowing (p = 0.012), Smiling Distress (p = 0.037), and Speaking Distress (p = 0.001). Reconstruction of posterolateral mandibular defects has a similar complication profile when utilizing a bony or soft tissue free flap. Bony flaps may perform better with respect to PROMs. Reconstructive surgeons should consider using bony flap reconstruction to achieve higher patient satisfaction and quality of life.

Nonvascularized bone grafts: how successful are they in reconstruction of segmental mandibular defects?

ObjectiveSegmental mandibular defects can occur due to various etiologies, including trauma and tumor resection. Reconstruction should provide adequate support for subsequent dental rehabilitation and allow for proper occlusion. Non-vascularized bone grafts have been used for reconstructing mandibular defects in cases where vascularized grafts were not feasible. The objective of this study was to assess the success rate of these grafts in reconstruction of segmental defects of various sizes in the mandible. Study DesignFifty patients were included in this retrospective chart review. Length of the grafts varied from 3 to 20 cm and patients were followed-up from 4 to 80 months. Fifteen grafts were harvested from anterior iliac crest, 23 from posterior iliac crest, 9 grafts were a combination of either with costochondral graft, and 3 were solely allografts. Bone morphogenetic protein was utilized in 41 cases as an adjunct. ResultsSuccess was defined as continuity of bone clinically and radiographically at a 4-month follow-up. Non-vascularized bone grafting was successful in %90 of cases. Complications were observed in %34 of cases, of which the most common were infection followed by wound dehiscence. ConclusionOur study demonstrated substantial success rate with non-vascularized bone grafts in reconstruction of segmental mandibular defects.

Bone repair potential of collagen-poly(3-hydroxybutyrate)-carbon nanotubes scaffold loaded with mesenchymal stem cells for the reconstruction of critical-sized mandibular defects

The poor structural stability of collagen (COL) upon hydration poses a significant challenge in tissue engineering (TE). To overcome this limitation, the incorporation of hydrophobic polymers such as poly(3-hydroxybutyrate) (PHB), and nanomaterials such as carbon nanotubes (CNTs) has been explored. In this study, we investigated the physical, chemical, and biological characteristics of COL-based scaffolds modified with PHB and CNTs for bone tissue engineering (BTE) applications. The tensile strength analysis revealed a substantial improvement in the ultimate tensile strength with the addition of 10 % PHB and 4 % CNTs. Scanning electron microscopy (SEM) images depicted a denser and more compact structure resulting from the presence of PHB and CNTs, enhancing the scaffold's mechanical properties. Fourier-transform infrared spectroscopy (FTIR) confirmed the successful incorporation of PHB and CNTs into the composite scaffold, maintaining the chemical integrity of COL. Stereological studies also conducted in a rat model with induced critical-sized bone defects in the mandibular bone further emphasize the substantial increase in bone formation and reduction in defect volume achieved by the scaffold loaded with stem cells. These findings underscore the promising approach to enhance bone healing, using COL-based scaffolds loaded with stem cells, and the favorable results obtained in this study can contribute to the advancement of BTE strategies.

Histological Evaluation of A unilateral Critical-Sized Mandibular Defect Reconstruction using human dental pulp stem cells by Light Microscope and Real-Time Quantitative PCR

Objective: To evaluate the osteogenic differentiation potential of human dental pulp stem cells (DPSCs) isolated from the dental pulp of third molar teeth in vitro cultures, and to evaluate the bone regenerative capacity of human dental pulp stem cells (DPSCs) when transplanted into a unilateral critical-sized bone defect in the mandibular bone in vivo after receiving a hydroxyapatite matrix and polylactic-polyglycolic acid (HA/PLGA) scaffold. Material and methods: A total of 18 mandibular defects were made, and three groups (each n = 6) were created. The first group: the transplanted DPSCs implanted in the critical-sized bone defect after receiving (HA/PLGA) scaffold. The second group received only (HA/PLGA) scaffold. The third group, which served as the control, had a critical-sized defect left empty. After characterization, Von Kossa [VK] and Alizarin red staining were employed to identify differentiated osteoblasts at the 14th and 21st days, and histological analyses, as well as polymerase chain reactions (PCR), were also used. Results: It showed that DPSCs had high proliferation potential and typical fibroblastic shape. Additionally, osteogenic differentiation of DPSCs was validated by morphological alterations, histological examination, and the expression of lineage-specific genes confirmed osteogenic differentiation of DPSCs. Conclusion: High proliferation potential and the capacity to differentiate into osteoblasts are two characteristics of DPSCs taken from impacted third molars.

Three-dimensional printed titanium mesh combined with iliac cancellous bone in the reconstruction of mandibular defects secondary to ameloblastoma resection

BackgroundThe reconstruction of large mandibular defects is a challenge, and free vascularized bone flaps are most commonly used. However, the precision and symmetry of this repair are deficient, and patients have a risk of vascular embolism, flap necrosis, and donor site complications. Therefore, to explore an ideal alternative in mandibular reconstruction with high surgical accuracy and low complications is indispensable.MethodsSeven patients with recurrent or large-scope ameloblastoma were enrolled in this study. All patients were provided with a fully digital treatment plan, including the design of osteotomy lines, surgical guides, and three-dimensional printed titanium mesh for implantation. With the assistance of surgical guide, ameloblastomas were resected, and custom 3D printed titanium mesh combined with posterior iliac bone harvest was used in mandibular reconstruction. A comparison was made between the discrepant surgical outcomes and the intended surgical plan, as well as the average three-dimensional deviation of the mandible before and after the surgery. At the same time, the resorption rate of the implanted bone was evaluated.ResultsAll patients completed the fully digital treatment process successfully without severe complications. Image fusion showed that the postoperative contour of the mandible was basically consistent with surgical planning, except for a slight increase in the inferior border of the affected side. The mean three-dimensional deviation of the mandible between the preoperative and postoperative periods was 0.78 ± 0.41 mm. The mean error between the intraoperative bone volume and the digital planning bone volume was 2.44%±2.10%. Furthermore, the bone resorption rates of the harvested graft 6 months later were 32.15%±6.95%.ConclusionsThe use of digital surgical planning and 3D-printed templates can assist surgeons in performing surgery precisely, and the 3D-printed titanium mesh implant can improve the patient’s facial symmetry. 3D printed titanium mesh combined with posterior iliac cancellous bone graft can be regarded as an ideal alternative in extensive mandibular reconstruction.

Comparative evaluation of personalized 3D-printed scaffold-driven double-barrel fibula flap for the reconstruction of segmented mandibular defects

The challenge of reconstructing large mandibular bone defects with double-barrel fibula flap (DBFF) is limited by the availability of autogenous bone, which remains a significant issue in maxillofacial surgery. This study aims to compare the novel scaffold-driven double-barrel approach with the DBFF method, and investigate the biomechanical behavior of 3D-printed porous titanium scaffolds with varying design parameters. The mandibular reconstruction model underwent FEA in two surgery phases, under two experimental loads and two design parameters. The experimental scaffold design was categorized into 9 groups based on the porous diameters (DP = 4 mm, 5 mm, 6 mm) and strut diameters (DS = 0.4 mm,0.5 mm,0.6 mm). The results illustrated that the stress in fibula, cortical and trabecular bones for all groups were within the ranges of normal physiological levels. The porous scaffolds effectively transmit mechanical stimulation, resulting in bone graft materials achieving up to 99.9% strain, with low stiffness to avoid stress shielding. The study revealed that the design parameters of Group B and Group F were more conducive to meeting biomechanical demands and promoting bone regeneration. This study presents scientifically proven and effective clinical solution for restoring both function and aesthetics of mandibular defects, while also providing valuable insights for future design criteria in bone regeneration scaffolds.

Symmetrical Midfacial Growth After Pediatric Mandibular Reconstruction With Free Fibula Flap

Free fibula is the workhorse flap for mandibular reconstruction and is increasingly being used in pediatric patients. However, craniomaxillofacial growth and development involve interdependent processes, and it remains unknown whether mandibular reconstruction with free fibula allows symmetric growth of the midface. The study evaluated midfacial symmetry after pediatric mandibular defect reconstruction. This retrospective cohort study included pediatric patients aged ≤14years who underwent mandibular reconstruction with free fibula flap. Postoperative computed tomography data were obtained at predefined follow-up time points. Midfacial symmetry was evaluated based on 3-dimensional (3D) cephalometry. The predictor variable was the side of the midface (affected or healthy side relative to the mandibular defect). The primary outcome variable was postoperative midfacial symmetry (at 1week, 6months, 1year, 2years, and >3years, or after the age of 18years), assessed in horizontal, vertical, and anteroposterior dimensions using 3D cephalometry. Another outcome variable was patient satisfaction based on a self-evaluation using visual analog scoring. Sex, age, diagnosis, and type of denture restoration. Paired t tests were performed to assess the relationship between the predictor and outcome variables, with the significance level of P<.05. A total of 13 patients were included in this study (9 males and 4 females; mean age: 12.23±2.39years). The average distance from upper first molar point (U6) to the horizontal plane on the affected side became greater than on the healthy side (difference: 0.7±0.5mm to 1.6±1.4mm, P<.05), while the average distance from pterygomaxillary fissure to coronal plane on affected side became shorter than that on the healthy side (difference: 0.6±0.6mm to 1.2±1.1mm, P<.05) from 1year after the surgery. There were no statistically significant differences in the remaining measurements between the 2 sides (P>.05). All the patients were satisfied with their postoperative facial symmetry. There were no severe midface deformities after pediatric mandibular reconstruction with free fibula flap. Meanwhile, pediatric mandibular reconstruction and proper occlusion could promote midfacial growth and symmetry.