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Background Recently, medical rapid prototyping (MRP) models, fabricated with computer-aided design and computer-aided manufacture (CAD/CAM) techniques, have been applied to reconstructive surgery in the treatment of head and neck cancers. Here, we tested the use of preoperatively manufactured reconstruction plates, which were produced using MRP models. The clinical efficacy and esthetic outcome of using these products in mandibular reconstruction was evaluated. Methods A series of 28 patients with malignant oral tumors underwent unilateral segmental resection of the mandible and simultaneous mandibular reconstruction. Twelve patients were treated with prebent reconstruction plates that were molded to MRP mandibular models designed with CAD/CAM techniques and fabricated on a combined powder bed and inkjet head three-dimensional printer. The remaining 16 patients were treated using conventional reconstruction methods. The surgical and esthetic outcomes of the two groups were compared by imaging analysis using post-operative panoramic tomography. Results The mandibular symmetry in patients receiving the MRP-model-based prebent plates was significantly better than that in patients receiving conventional reconstructive surgery. Conclusions Patients with head and neck cancer undergoing reconstructive surgery using a prebent reconstruction plate fabricated according to an MRP mandibular model showed improved mandibular contour compared to patients undergoing conventional mandibular reconstruction. Thus, use of this new technology for mandibular reconstruction results in an improved esthetic outcome with the potential for improved quality of life for patients.

Background Advanced head and neck malignancies with underlying bony involvement often require aggressive oncological resection of large segments of the oral cavity including the mandible. These patients require vascularized donor osseous free tissue transfer to reconstruct significant defects. Traditionally, the donor bone is harvested on its vascular supply and shaped to the defect in a free hand fashion (FHS). However, virtual surgical planning (VSP) has emerged as a method to optimize reconstructive outcomes and decrease operative time. The goals of this study are to assess superiority of VSP to FHS by comparing bony union rates at 12 months, short and long-term complication rates, reconstruction accuracy, quality of life (QOL), functional outcomes, and economic analysis. Methods This is a multicenter phase II/III study randomizing four hundred twenty head and neck patients undergoing mandibulectomy in a 1:1 ratio between VSP and FHS. Intention-to-treat analysis will be performed for patients enrolled but unable to undergo VSP-aided reconstruction. The primary endpoint is bony-union rates at 1 year post-operatively. Secondary outcomes include complication rates, QOL, functional outcomes, and economic burden. Discussion This study will provide an assessment of two different surgical approaches to the reconstructive methods of mandible defects using fibular or scapular free flaps on bony-union rates, complications, QOL and economics. Trial registration Clinicaltrials.gov identifier: NCT05429099. Date of registration: June 23, 2022. Current version: 1.0 on March 6, 2024.

The purpose of the study was to compare the accuracy of computer-assisted surgery (CAS) and the traditional freehand technique for fibular free flap mandibular reconstruction as well as to evaluate the accuracy of the CAS planning. The medical records of 18 patients who underwent mandibular reconstruction with fibular free flap were reviewed. The CAS group ( n  = 7) benefited from virtual surgical planning and custom patient-specific plates and surgical cutting guides. The Control group ( n  = 11) was treated by conventional surgery. Morphometric comparison was done by calculating the differences in specific linear and angular parameters on pre- and postoperative CT-scans for both groups by using ProPlan CMF ® software. Symmetry was also assessed by calculating the ratio of the affected versus the nonaffected side. In the CAS group, planned and postoperative CT-scans were compared to evaluate accuracy. The morphometric comparison showed no statistically significant differences between the groups except for the axial angle on the nonaffected side (mean difference 1.0° in the CAS group versus 2.9° in the Control group; p  = 0.03). Ratios of the affected side over the nonaffected side showed no differences between the two groups. In the CAS group, the accuracy assessment showed a mean distance deviation of 2.3 mm for mandibular osteotomies and 1.9 mm for fibular osteotomies. Our results indicated that CAS and the conventional freehand techniques were comparable in their ability to provide a satisfactory morphological fibular free flap mandibular reconstruction. Moreover, the accuracy of the CAS technique was within the range reported in the literature.

Free-flap mandibular reconstruction is a highly specialized procedure associated with severe complications necessitating re-interventions and re-hospitalizations. This surgery is expensive in terms of health workers’ time, equipment, medical devices and drugs. Our main objective was to assess the direct hospital cost generated by osseocutaneous free-flap surgery in a multicentric prospective micro-costing study. Direct medical costs evaluated from a hospital perspective were assessed using a micro-costing method from the first consultation with the surgeon until the patient returns home, thus confirming the success or failure of the free-flap procedure. The mean total cost for free-flap intervention was 34,009€ (5151–119,604€), the most expensive item being the duration of hospital bed occupation, representing 30–90% of the total cost. In the event of complications, the mean cost increased by 77.3%, due primarily to hospitalization in ICU and the conventional unit. This surgery is effective and provides good results but remains highly complex and costly.

To investigate bone remodelling responses to mandibulectomy, a joint external and internal remodelling algorithm is developed here by incorporating patient-specific longitudinal data. The primary aim of this study is to simulate bone remodelling activity in the conjunction region with a fibula free flap (FFF) reconstruction by correlating with a 28-month clinical follow-up. The secondary goal of this study is to compare the long-term outcomes of different designs of fixation plate with specific screw positioning. The results indicated that the overall bone density decreased over time, except for the Docking Site (namely DS1, a region of interest in mandibular symphysis with the conjunction of the bone union), in which the decrease of bone density ceased later and was followed by bone apposition. A negligible influence on bone remodeling outcome was found for different screw positioning. This study is believed to be the first of its kind for computationally simulating the bone turn-over process after FFF maxillofacial reconstruction by correlating with patient-specific follow-up.

Vascularized autologous bone transplantation combined with implant restoration is a preferred method for functional mandibular reconstruction. However, there is currently no consensus on whether internal fixation devices, such as titanium plates and screws, must be removed during the reconstruction process. This study aimed to assess the biomechanical and clinical necessity of removing these fixation devices. Eight patients who underwent mandibular reconstruction with fibula flaps and subsequent dental implantation were included. The study utilized finite element analysis to simulate and compare biomechanical stress distributions in models where fixation devices were either retained or removed. The clinical outcomes including peri-implant health, masticatory efficiency, and oral health-related quality of life were evaluated through follow-up examinations and standardized questionnaires. The biomechanical analysis indicated that the maximum stress on the grafted fibula surrounding the implants was significantly lower in the retention group (42.07 ± 12.06 MPa) compared to the removal group (44.892 ± 14.80 MPa, P = 0.017*). Furthermore, a positive correlation was identified between the simulated stress levels on the implants and the severity of gingival bleeding (coefficient: 0.82, P = 0.013*). Clinically, while there were no significant differences in marginal bone loss between the two approaches, patients who retained the internal fixation devices reported better quality of life scores regarding functional limitations and physical pain. In conclusion, retaining internal fixation devices appears to reduce mechanical stress on the peri-implant fibula graft and is associated with improved patient-reported outcomes. These findings suggest that the routine removal of reconstruction plates may not be necessary and that retention can favour peri-implant health and patient comfort.

At present, mandibular reconstruction with a fibular free flap is the gold standard for functional and esthetic rehabilitation after oncological surgery. The purpose of this study was to describe the computer-assisted mandibular reconstruction procedure adopting the customized solution Synthes ProPlan CMF. The study reports five consecutive patients with benign or malignant disease requiring mandibular reconstruction using a microvascular fibular free flap, pre-operative virtual planning, construction of cutting guides and customized laser pre-bent titanium plates. The surgical technique is discussed in a step-by-step fashion. The average post-operative hospital stay was 18 ± 3 days. Ischemia time was recorded in all five cases, with an average of 75 ± 8 min. No problems were encountered in any surgical step and there were no major complications. Excellent precision of cutting guides and a good fit of pre-bent plates were found on both the mandible and fibula. There was excellent precision in bone to bone contact and position between mandible and fibula graft. Measurement data from the pre-operative and post-operative CT scans were compared. The average difference (Δ) between programed segment lengths and CT control segment lengths was 0.098 ± 0.077 cm. Microsurgical mandibular reconstruction using a virtual surgical planning yields significantly shorter ischemia times and allows more precise osteotomies. The technology is becoming increasingly recognized for its ability to optimize surgical outcomes and minimize operating time. Considering that the extent of resection can be wider than predicted, this results in safer modeling of the fibula only after frozen sections have demonstrated the radicality of resection.

Purpose For the new generation of mandibular reconstruction, patient-specific mandible reconstruction plates (PSMPs) have been developed which are milled from titanium after preoperative computer planning using CAD/CAM procedures. Resection margins and plate position are determined by surgical guides. In addition, length and shape of the plate and the number and angulation of the screw holes can be planned. Methods 30 patients received such PSMP. Indication ranged from stabilization osteosynthesis, single alloplastic stand-alone reconstruction to microvascular reconstructions. Time for planning, fit of surgical guides and plates, pre-/postoperative occlusion, radiological position of the temporo mandibular joint and complications were recorded.Results The median time for online planning was 35 min. The results concerning fit and handling of the PSMP and the surgical guides were mainly very positive. In six cases, the plan had to be adapted to the intraoperative clinical needs. The postoperative position of the condyles in the temporo mandibular fossae was regular in 28 cases. The evaluation of the occlusion was not representative due to not clearly identifiable occlusion in 2/3 of the cases. Nevertheless, complications like postoperative extraoral plate exposure, infection, graft and flap necrosis or difficulties to position the guides or the plate during surgery occurred.Conclusions Mandibular reconstruction with PSMP offers a broad range of opportunities and benefits compared with standard procedures and can be recommended for all kind of mandibular reconstructions. It is not yet foreseeable whether PSMP will in future become routine clinical practice for mandibular reconstruction or will be confined to selected isolated cases.

Assessing accuracy in CAD-CAM mandibular reconstruction poses significant challenges but is essential for ensuring reliable outcomes. Existing methods are often operator-dependent, lacking repeatability and reproducibility. This study introduces the Global Positioning Layout (GPL) method, an accuracy assessment technique integrated into the reconstruction protocol based on CAD-CAM and additive printing technology. We describe its methodology and present its implementation through an automated workflow. Key principles of accuracy assessment were identified and structured as Requirements, Data input, Data reference system, and Data output. The necessary 3D virtual models were defined: planned mandible, reference mandible, patient-specific implant (PSI), postoperative mandible, and postoperative PSI. A unique coordinate system (GPL-RS) was built on the reference mandible. Three Roto-Translational Matrices (RTMs) were applied to measure movements and deviations between the designed and postoperative models to assess reconstruction accuracy. Five clinical cases with different operational diseases and defects were analysed, comparing spatial deviations between manual and automated methods. The GPL method represents a promising advancement in assessing the accuracy of CAD-CAM reconstructions, providing valuable insights that can improve surgical outcomes.

In cases of large mandibular continuity defects resulting from malignancy resection, the current standard of care involves using patient-specific/custom titanium reconstruction plates along with autogenous grafts (fibula, scapula, or iliac crest segments). However, when grafts are not feasible or desired, only the reconstruction plate is used to bridge the gap. Unfortunately, metal osteosynthesis and reconstruction plates, including titanium, exhibit adverse effects such as stress-shielding and limitations in accurate postoperative irradiation (especially with proton-beam therapy). To address these issues, in this study we explore, develop and validate a non-metallic solution: a topology-optimized polyetheretherketone (PEEK) load-bearing implant for large non-grafted mandibular continuity defects. In order to thoroughly validate the developed PEEK reconstruction, a dedicated MANDYBILATOR testing apparatus was developed. Using the MANDYBILATOR finite element analysis results of the implant were confirmed and the PEEK implant was mechanically validated for both static and dynamic loading. Results show that the PEEK reconstructed mandible is comparably strong as the unreconstructed mandible and is unlikely to fail due to fatigue. Our PEEK implant design has the mechanical potential to act as a substitute for the current titanium plates used in the reconstruction of continuity defects of the mandible. This may potentially lead to optimised patient-specific reconstructions, with the implants matching the bone’s stiffness and possessing radiolucent properties which are useful for radiographic follow-ups and radiotherapy. Furthermore, the addition of the dynamic/cyclic MANDYBILATOR apparatus allows for more realistic application of the in-vivo loading of the mandible and can provide added insights in biomechanical behaviour of the mandible.