Reconstruction of mandible using a computer-designed 3D-printed patient-specific titanium implant: a case report

Autogenous, alloplastic, or hybrid for total mandibular reconstruction; is here an optimal path?

For less fit patients, total reconstruction of the mandible (TRM) is an elucidated alternative for severe maxillofacial defects. This study aimed to comprehensively review and analyze the existing evidence, irrespective of the underlying pathologies, to provide a consolidated overview of the current state of TRM. An electronic search was performed on PubMed, Embase, Scopus, and Google Scholar to identify studies reporting TRM without restrictions on patient age, type of pathology underlying the mandibular defect, and study type. Electronic search identified 390 studies; only 21 met the inclusion criteria, documenting 7 (33.3%) autogenous, 6 (28.6%) alloplastic, and 8 (38.1%) hybrid TRMs. All studies reported one clinical case, except for two studies that reported two patients treated with TRM. The mean age of the patients was 39.0 ± 19.4 years, and the mean follow-up was 22.3 ± 14.7 months. Osteomyelitis was the most common pathology. Bilateral condyles were preserved in only two cases. The TRM has been reported in clinical cases only and no large cohort study is available. Functional and aesthetic parameters have either not been reported or have been reported in heterogeneous formats, thus hampering comparisons of autogenous, alloplastic, and hybrid TRMs. Overall, TRM in patients presenting with severe maxillofacial defects achieved promising clinical outcomes endowed with acceptable function and aesthetics. Large cohort studies are needed to validate these results.

Innovative principle of implant-oriented fibula placement in mandibular reconstruction using double-barrel fibula and simultaneous implants: A technical note

Simultaneous or secondary inserted implants with double-barrel fibula to reconstruct the mandible have become a common method. However, difficulties in later restoration caused by placement errors of fibula or incipiently placed implants have also been reported in some studies. This note describes a novel technique of implant-oriented guide plates helpful for mandible ablation, fibula segmentation and positioning, and implant placement. We design a series of guide plates especially an implant-fibula placing guide plate, and record and fix the relative spatial positions of the remaining teeth, the simultaneous implants and upper fibula. During surgery, the placement of upper fibula is oriented towards appropriate placement of implants. Therefore, the position of upper fibula can meet the requirements of simultaneous implant as much as possible. Within the limits of present observation, we believe that this technique may increase the manipuility while reducing the errors and the risk of complications.

Considerations for the Use of Alloplastic Temporomandibular Joint Replacement in Irradiated Patients: Report of an Off-Label Indication

BACKGROUND

Custom-made alloplastic temporomandibular joint replacement (ATMJR) is not validated in irradiated patients. However, in specific situations, after previous reconstructive surgical failures, the authors hypothesized the role of a customized ATMJR after radiotherapy.

METHODS

A 65-year-old male patient was referred to Instituto Português da Face-Lisbon, Portugal-after failed attempts of mandibular reconstruction secondary to oral carcinoma resection and partial hemi-mandibulectomy plus radiotherapy of 60 total Grays. Primary reconstruction was performed with fibula free flap. Due to failure, secondary reconstructions were performed with osteosynthesis plate without success. The patient was unable to have adequate mastication and deglutition due to a severe crossbite. The authors treated the patient with an extended customized alloplastic temporomandibular joint replacement (F0M2).

RESULTS

With 3 years of follow-up, the patient showed an improvement in masticatory function, mandibular motion, pain levels, and overall quality of life. No complications were observed related to ATMJR.

CONCLUSIONS

The presented case described how ATMJR, although not a validated option after radiotherapy, can be considered to restore functionality in complex cases with bone and soft tissues problems.

From bench to bedside - current clinical and translational challenges in fibula free flap reconstruction

Fibula free flaps (FFF) represent a working horse for different reconstructive scenarios in facial surgery. While FFF were initially established for mandible reconstruction, advancements in planning for microsurgical techniques have paved the way toward a broader spectrum of indications, including maxillary defects. Essential factors to improve patient outcomes following FFF include minimal donor site morbidity, adequate bone length, and dual blood supply. Yet, persisting clinical and translational challenges hamper the effectiveness of FFF. In the preoperative phase, virtual surgical planning and artificial intelligence tools carry untapped potential, while the intraoperative role of individualized surgical templates and bioprinted prostheses remains to be summarized. Further, the integration of novel flap monitoring technologies into postoperative patient management has been subject to translational and clinical research efforts. Overall, there is a paucity of studies condensing the body of knowledge on emerging technologies and techniques in FFF surgery. Herein, we aim to review current challenges and solution possibilities in FFF. This line of research may serve as a pocket guide on cutting-edge developments and facilitate future targeted research in FFF.

An overview of 3D printed metal implants in orthopedic applications: Present and future perspectives

With the ability to produce components with complex and precise structures, additive manufacturing or 3D printing techniques are now widely applied in both industry and consumer markets. The emergence of tissue engineering has facilitated the application of 3D printing in the field of biomedical implants. 3D printed implants with proper structural design can not only eliminate the stress shielding effect but also improve in vivo biocompatibility and functionality. By combining medical images derived from technologies such as X-ray scanning, CT, MRI, or ultrasonic scanning, 3D printing can be used to create patient-specific implants with almost the same anatomical structures as the injured tissues. Numerous clinical trials have already been conducted with customized implants. However, the limited availability of raw materials for printing and a lack of guidance from related regulations or laws may impede the development of 3D printing in medical implants. This review provides information on the current state of 3D printing techniques in orthopedic implant applications. The current challenges and future perspectives are also included.

Tenants of Mandibular Reconstruction in Segmental Defects

The premises of mandibular reconstruction are the restoration of occlusion and mandibular contour for the purpose of preserving the facial identity, oral airway, and effective speech and mastication. Establishing functional occlusion is the primary tenant in all mandibular reconstruction. In cases of segmental defects, particularly in dentate regions of the mandible, there has been a paradigm shift over the past two decades in how surgeons are approaching the restoration of load-bearing mandibular continuity with capacity for dental implantation. Here we discuss considerations for deciding the most effective method of reconstruction in segmental defects.

Do Case Reports on Total Mandibular, Extended, and Bilateral Total Temporomandibular Joint Reconstruction Prostheses Adhere to the Surgical CAse REport Guidelines?

PURPOSE

The Surgical CAse REport (SCARE) guidelines are a standardized format for reporting surgical cases. The aim of this study was to evaluate the completeness of case reports documenting alloplastic reconstruction of large craniomaxillofacial defects involving total mandibular, bilateral, and extended temporomandibular joint in major high-quality craniomaxillofacial journals, based on the SCARE guidelines.

METHODS

An extensive online search was performed according to the Priority Reporting Items for Systematic Reviews and Meta-Analyses statement in PubMed, Embase, Scopus, Google Scholar, and Dimensions databases to identify relevant case reports. Each selected case report was assessed on 16 topics (38 items) of the SCARE guidelines, using a scoring scale of "0" (No/noncompliance), "1" (Yes/compliance), and 2" (unclear). The completeness of reporting (COR) score was calculated as the ratio of "yes" responses to "total" (ie, yes + no + unclear) responses. Adequacy of case reporting was denoted by a COR score of 70% or more.

RESULTS

A total of 35 case reports were selected, where the male to female patients ratio was 3:4 cases, mean ± standard deviation (SD) age: 34.9 ± 16.7 years, mean ± SD follow-up duration: 17.0 ± 12.9 months, and number of patients with left, right, and bilateral temporomandibular joint reconstruction prostheses were 16, 10, and 09, respectively. The mean ± SD COR score for all 35 case reports and the individual item of the SCARE guidelines was 70.2 ± 10.5% and 66.5 ± 31.2%, respectively. The minimum and maximum COR score was found for "Keywords" (0.0%) and "Introduction" (100%) and "Clinical Findings" (100%), respectively. Adequate reporting was found for 20/35 (57%) case reports.

CONCLUSIONS

This study revealed that case reports in major high-quality craniomaxillofacial journals suffer from insufficient reporting. Widespread adoption of available standards, such as SCARE guidelines, is proposed to improve the quality and robustness of case reporting.

Patient Specific Alloplastic Implant Reconstruction of Mandibular Defects-Safe Practice Recommendations and Guidelines

Mandibular continuity defects are commonly seen after tumor resection, osteomyelitis or maxillofacial trauma. Three-dimensional reconstruction of these mandibular segmental defects is critical for proper mandibular functioning and esthetics. Various methods used to reconstruct such defects include bridging reconstruction plates, modular endoprosthesis, non-vascularized and vascularized bone grafting with stock reconstruction plate or patient specific implants (PSI) and tissue engineering bone transfer. But in the recent years, literature documents use of PSI only alloplastic reconstruction as an alternate to microvascular bone flap reconstruction. Representative cases enumerate current practice of 'patient specific implant only' mandibular reconstruction and its pitfalls. This article discusses current status of literature on PSI's, choice of indications for 'PSI only' mandibular reconstruction and also proposes guidelines for safe practice of patient specific implant reconstruction of mandible.

Scope of PSI in Maxillofacial Region: Our Experience

Introduction

Patient-specific implants aided by 3D virtual planning and CAD-CAM technology represents the next frontier in rehabilitation of complex maxillofacial defects slowly replacing the gold standard autografts as the preferred mode of reconstruction.

Methods

In a first of its kind case series, we describe eight cases of complex maxillofacial defects managed by patient-specific implants at AFDC, New Delhi. All the designs went through stringent FEA analysis and GOM analysis to standardize the implant for achieving optimal functionality. We also added integrated dental implant component in the PSI to achieve immediate postoperative dental rehabilitation.

Conclusion

This case series adds to literature the varying scenarios in which PSI's can be used in the maxillofacial region with functional dental rehabilitation thus paving a way for a new era in reconstruction.

The Possibilities of Personalized 3D Printed Implants-A Case Series Study

Background and Objectives: Following the most recent software and 3D printing developments, the use of personalized 3D printed orthopedic implants for treatment of complicated surgical cases has gained more popularity. Today, orthopedic problems that cannot be solved with standard implants may be effectively addressed using personalized prostheses. The aim of this study is to present the designing, modeling and production stages of four different personalized 3D printed prostheses and their application in clinical cases of patients who underwent treatment in various anatomical locations with a precisely specified indication for implantation. Materials and Methods: Based on computed tomography scanning, personalized 3D printed prostheses were designed, produced and used in four patients within a period of three to five days after injury or admission. Results: Early term follow-ups demonstrated good to excellent results. Conclusions: Personalized 3D printed prostheses offer an opportunity for a treatment of choice and provide good anatomical and functional results, shortened surgical time, less complications, and high satisfaction in patients with appropriate indications. The method should be considered primarily for patients with large bone defects, or such indicated for resection. Personalized 3D printed prostheses have the potential to become more common and beneficial in the future.

In Vivo Bone Tissue Engineering Strategies: Advances and Prospects

Reconstruction of critical-sized bone defects remains a tremendous challenge for surgeons worldwide. Despite the variety of surgical techniques, current clinical strategies for bone defect repair demonstrate significant limitations and drawbacks, including donor-site morbidity, poor anatomical match, insufficient bone volume, bone graft resorption, and rejection. Bone tissue engineering (BTE) has emerged as a novel approach to guided bone tissue regeneration. BTE focuses on in vitro manipulations with seed cells, growth factors and bioactive scaffolds using bioreactors. The successful clinical translation of BTE requires overcoming a number of significant challenges. Currently, insufficient vascularization is the critical limitation for viability of the bone tissue-engineered construct. Furthermore, efficacy and safety of the scaffolds cell-seeding and exogenous growth factors administration are still controversial. The in vivo bioreactor principle (IVB) is an exceptionally promising concept for the in vivo bone tissue regeneration in a predictable patient-specific manner. This concept is based on the self-regenerative capacity of the human body, and combines flap prefabrication and axial vascularization strategies. Multiple experimental studies on in vivo BTE strategies presented in this review demonstrate the efficacy of this approach. Routine clinical application of the in vivo bioreactor principle is the future direction of BTE; however, it requires further investigation for overcoming some significant limitations.

Effect Comparison of Assisted Surgery Simulated by Preoperative 3D Reconstruction and Minimally Invasive Surgery with the Assist of Knee Arthroscopy in the Treatment of Tibial Plateau Fracture under the Background of Intelligent Medicine

Objective

To explore the effect comparison of the assisted surgery simulated by preoperative 3D reconstruction and the minimally invasive surgery with the assist of knee arthroscopy in the treatment of tibial plateau fracture (TPF) under the background of intelligent medicine.

Methods

100 patients with TPF admitted to our hospital from January 2021 to January 2022 were selected as the study subjects. According to the order of admission, the patients were divided into the simulation group with 3D reconstruction (n = 50) and the auxiliary group with knee arthroscopy (n = 50), and the clinical indicators were compared between the two groups.

Results

There was no significant difference in any other clinical treatment indexes between the two groups except the surgery time (P > 0.05), and there was no significant difference in knee flexion ability, walking ability, and Rasmussen scores between the two groups after treatment (P > 0.05). However, compared with the auxiliary group with knee arthroscopy, the mean posterior slope angle and varus angle of the patients were significantly higher (P < 0.001), and the total incidence of complications was significantly lower (P < 0.05).

Conclusion

Based on the analysis under the background of intelligent medicine, it is found that the assisted surgery simulated by preoperative 3D reconstruction has a better effect and a higher safety, but they have the similar effects on improving the knee joint function of patients.

Preparation and Characterization of Vancomycin Hydrochloride-Loaded Mesoporous Silica Composite Hydrogels

This study aims to explore the feasibility of the novel temperature-sensitive hydrogel-based dual sustained-release system (Van/SBA-15/CS-GP-SA) in the repair and treatment of infectious jaw defects. Van/SBA-15 was prepared using the mesoporous silica (SBA-15) as a carrier for vancomycin hydrochloride (Van), and Van/SBA-15 was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectrometry (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR), Brunauer-Emmett-Teller (BET), and Barrett-Joyner-Halenda (BJH). The characterization results confirm that Van is loaded in SBA-15 successfully. Van/SBA-15/CS-GP-SA is constructed by encapsulating Van/SBA-15 in chitosan-sodium glycerophosphate-sodium alginate hydrogel (CS-GP-SA). The microstructures, sustained-release ability, biocompatibility, and antibacterial properties of Van/SBA-15/CS-GP-SA were systematically studied. Van/SBA-15/CS-GP-SA is found to have promising sustained-release ability, outstanding biocompatibility, and excellent antibacterial properties. This study provides new ideas for the management of infectious jaw defects.

Improving mandibular reconstruction by using topology optimization, patient specific design and additive manufacturing?-A biomechanical comparison against miniplates on human specimen

In this study, topology optimized, patient specific osteosynthesis plates (TOPOS-implants) are evaluated for the mandibular reconstruction using fibula segments. These shape optimized implants are compared to a standard treatment with miniplates (thickness: 1.0 mm, titanium grade 4) in biomechanical testing using human cadaveric specimen. Mandible and fibula of 21 body donors were used. Geometrical models were created based on automated segmentation of CT-scans of all specimens. All reconstructions, including cutting guides for osteotomy as well as TOPOS-implants, were planned using a custom-made software tool. The TOPOS-implants were produced by electron beam melting (thickness: 1.0 mm, titanium grade 5). The fibula-reconstructed mandibles were tested in static and dynamic testing in a multi-axial test system, which can adapt to the donor anatomy and apply side-specific loads. Static testing was used to confirm mechanical similarity between the reconstruction groups. Force-controlled dynamic testing was performed with a sinusoidal loading between 60 and 240 N (reconstructed side: 30% reduction to consider resected muscles) at 5 Hz for up to 5 · 10⁵ cycles. There was a significant difference between the groups for dynamic testing: All TOPOS-implants stayed intact during all cycles, while miniplate failure occurred after 26.4% of the planned loading (1.32 · 10⁵ ± 1.46 · 10⁵ cycles). Bone fracture occurred in both groups (miniplates: n = 3, TOPOS-implants: n = 2). A correlation between bone failure and cortical bone thickness in mandible angle as well as the number of bicortical screws used was demonstrated. For both groups no screw failure was detected. In conclusion, the topology optimized, patient specific implants showed superior fatigue properties compared to miniplates in mandibular reconstruction. Additionally, the patient specific shape comes with intrinsic guiding properties to support the reconstruction process during surgery. This demonstrates that the combination of additive manufacturing and topology optimization can be beneficial for future maxillofacial surgery.

Patient-Specific Surgical Implant Using Cavity-Filled Approach for Precise and Functional Mandible Reconstruction

Mandibular reconstruction is a complicated task because of the complex nature of the regional anatomy. Computer-assisted tools are a promising means of improving the precision and safety of such complex surgeries. The digital techniques utilized in the reconstruction of mandibular defects based on medical data, computer-aided-design approaches, and three-dimensional (3D) printing are widely used to improve the patient’s aesthetic appearance and function, as well as the accuracy and quality of diagnosis, and surgical outcomes. Nevertheless, to ensure an acceptable aesthetical appearance and functional outcomes, the design must be based on proper anatomical reconstruction, mostly done in a virtual environment by skilled design engineers. Mirroring is one of the widely used techniques in the surgical navigation and reconstruction of mandibular defects. However, there are some discrepancies and mismatches in the mirrored anatomical models. Hence, in order to overcome these limitations in the mirroring technique, a novel approach called the cavity-filled technique was introduced. The objective of this study was to compare the accuracy of the newly recommended cavity-filled technique with the widely used mirror reconstruction technique in restoring mandibular defects. A prominent 3D comparison technique was employed in this work, where the resected and the reconstructed mandibles were superimposed to quantify the accuracy of the two techniques. From the analysis, it can be inferred that the cavity-filled technique with a root-mean-square value of 1.1019 mm produced better accuracy in contrast to the mirroring approach, which resulted in an error of 1.2683 mm. Consequently, by using the proposed cavity-filled design, the discrepancy between the reconstruction plate and the bone contour was mitigated. This method, owing to its high precision, can decrease the number of adjustments and the time of surgery, as well as ensure a quick recovery time with better implant tissue in-growth.