Explore the vast range of titles available.

Objective To evaluate the feasibility and accuracy of implementing three‐dimensional virtual surgical planning (VSP) and subsequent transfer by additive manufactured tools in the secondary reconstruction of residual post‐traumatic deformities in the midface. Methods Patients after secondary reconstruction of post‐traumatic midfacial deformities were included in this case series. The metrical deviation between the virtually planned and postoperative position of patient‐specific implants (PSI) and bone segments was measured at corresponding reference points. Further information collected included demographic data, post‐traumatic symptoms, and type of transfer tools. Results Eight consecutive patients were enrolled in the study. In five patients, VSP with subsequent manufacturing of combined predrilling/osteotomy guides and PSI was performed. In three patients, osteotomy guides, repositioning guides, and individually prebent plates were used following VSP. The median distances between the virtually planned and the postoperative position of the PSI were 2.01 mm (n = 18) compared to a median distance concerning the bone segments of 3.05 mm (n = 12). In patients where PSI were used, the median displacement of the bone segments was lower (n = 7, median 2.77 mm) than in the group with prebent plates (n = 5, 3.28 mm). Conclusion This study demonstrated the feasibility of VSP and transfer by additive manufactured tools for the secondary reconstruction of complex residual post‐traumatic deformities in the midface. However, the median deviations observed in this case series were unexpectedly high. The use of navigational systems may further improve the level of accuracy. To evaluate the feasibility and accuracy of implementing three‐dimensional virtual surgical planning (VSP) and subsequent transfer by additive manufactured tools in the secondary reconstruction of residual post‐traumatic deformities in the midface. This study demonstrated the feasibility of VSP and transfer by additive manufactured tools for the secondary reconstruction of complex residual post‐traumatic deformities in the midface. However, the median deviations observed in this case series were unexpectedly high. The use of navigational systems may further improve the level of accuracy.

The need for customized implants has continuously increased, but patient-specific silicone implants are not yet commonly used in the plastic surgery market. We sought to validate the effectiveness of a 3D customized nasal implant design in terms of design and lead time compared with a manually customized implant by a surgeon. Based on the computed tomography (CT) findings of 15 patients who planned rhinoplasty, a surgeon wrote order forms reflecting the surgical plan and subsequently designed implants manually using epoxy on a 3D printed skull. Separately, engineers analyzed the CT findings and designed 3D implants based on the order forms. Epoxy designs were 3D-scanned, converted into a stereolithography format and compared with 3D implant designs to assess which method had a smaller margin of error as per the preoperative order form. Moreover, the lead time in all steps are compared. Nasion thickness, tip thickness, glabella starting point, glabella width, radix width, and total volume were comparatively analyzed. In all parameters, the error rate of the 3D design is relatively lower than that of the epoxy design. The former also had a lower total volume and a faster manufacturing time. With novel 3D customized nasal implants, the limitations of ready-made silicone implants are addressed, and it is now possible to preoperatively design implants more accurately, quickly, and conveniently.

The complexity of patient‐specific implants combined with the current limited expertise in reliability engineering and manufacturability in the additive manufacturing (AM) sector is posing a number of quality performance challenges. Worldwide medical device regulatory bodies are facing increasing pressure to devise adequate standards to ensure long‐term patient safety and product performance. The implementation of the Quality by Design (QbD) system to titanium 3D‐printed bone implants offers a proven system to ensure that products are designed and manufactured correctly from the beginning without errors. This article reports on the development of a failure mode, effects, and criticality analysis (FMECA) coupled with a 3D risk assessment approach. This integrated approach is based on a questionnaire performed with three industry firms and three university research groups with significant experience and expertise in medical device product development and/or research in this field. Research outcomes include a FMECA form containing 137 failure modes with AM materials, AM machine general, fabrication, electron beam melting machine, finishing, and design being as the most sensitive process areas in terms of product quality. We subsequently propose corresponding preventive and corrective strategies for risk mitigation. The approach forms part of the QbD system being developed by the authors specifically for additive manufactured titanium patient‐specific implants. This article reports on the development of a failure mode, effects, and criticality analysis (FMECA) coupled with a 3D risk assessment approach for titanium 3D‐printed bone implants. Research outcomes include the identification of 13 critical risks and a FMECA form containing 137 failure modes (FMs) with AM materials, AM machine general, fabrication, EBM machine, finishing, and design being as the most sensitive process areas in term of product quality. We subsequently proposed corresponding preventive and corrective strategies for risk mitigation.

The current study aims to present our clinical observations and experience gathered during the diagnosis, clinical presentation, medical/surgical treatment, and functional prosthetic rehabilitation of cases of rhino-orbital/cerebral Mucormycosis patients. Mucormycosis is an aggressive, life-threatening invasive fungal infection that occurs in people who are immune-compromised. The rise of ROCM during the second wave of the COVID-19 pandemic in India suggests a more effective association between Mucormycosis and the SARS-CoV-2 delta variant. The treatment strategy for Mucormycosis is an early diagnosis which is critical for a successful outcome. The initial step is to reduce or remove underlying risk factors followed by surgical excision and debridement of the afflicted tissues supplemented with antifungal medication. The first-line antifungal treatment is Liposomal Amphotericin B. Postsurgical resection defects are rehabilitated by either removable partial prosthesis (obturators) or by fixed zygomatic implant/patient-specific implant supported prosthesis. Management of ROCM requires a multidisciplinary approach. This case series highlights detailed medical, surgical, and functional prosthetic management modalities adopted by our team in managing such a dreaded disease which may be used as a tool for the formulation of standardized prevention and management/treatment/rehabilitation protocols in the future so that disease morbidity and mortality be reduced and an endemic outbreak could be averted.

BACKGROUND:Calvarial reconstruction of large cranial defects following decompressive surgery is challenging. Autologous bone cannot always be used due to infection, fragmentation, bone resorption, and other causes. Polyetheretherketone (PEEK) is a synthetic material that has many advantages in cranial-repair surgery, including strength, stiffness, durability, and inertness. OBJECTIVE:To describe our experience with custom-made PEEK implants for the repair of large cranial defects in 3 institutionsSan Francisco General Hospital, Hadassah-Hebrew University Hospital, and the National Neuroscience Institute, Singapore. METHODS:A preoperative high-resolution computed tomography scan was obtained for each patient for design of the PEEK implant. Cranioplasty was performed via standard technique with the use of self-tapping titanium screws and miniplates. RESULTS:Between 2006 and 2012, 66 cranioplasties with PEEK implants were performed in 65 patients (46 men, 19 women, mean age 35 ± 14 years) for repair of large cranial defects. There were 5 infections of implants and 1 wound breakdown requiring removal of the implant (infection and surgical removal rates of 7.6% and 9.1%, respectively). Two patients required drainage of postoperative hematoma (overall surgical complication rate, 12.7%). Nonsurgical complications in 5 patients included seizures, nonoperative collection, and cerebrospinal fluid rhinorrhea that resolved spontaneously. Overall median patient or family satisfaction with the cranioplasty and aesthetic result was good, 4 on a scale of 5. Temporal wasting was the main aesthetic concern. CONCLUSION:Custom-designed PEEK implants are a good option for patients with large cranial defects. The rate of complications is comparable to other implants or autologous bone. Given the large size of these defects, the aesthetic results are good. ABBREVIATIONS:MRSA, methicillin-resistant Staphylococcus aureusNNI, National Neuroscience Institute, SingaporePEEK, polyetheretherketoneSFGH, San Francisco General HospitalTBI, traumatic brain injury

The purpose of this study is to design a patient-specific TMJ implant and study its behaviour under different loading conditions compared with natural intact TMJ. There are several diseases, which affect the proper growth and function of TMJ, and in some cases, TMJ injury results from accidents. To repair the TMJ, temporomandibular joint replacement or TJR surgery is performed. In this work, CT-scan data of the skull and mandible region with broken condylar head were used to study the biomechanical behaviour of the intact mandible and customized TMJ prostheses in order to design a patient-specific total TMJ implant. The customized TMJ implant was virtually studied under simulated loading conditions using finite element method (FEM) in ANSYS Workbench and then compared to the intact jaw-mandible for the combinations of two different biocompatible material models. It is observed that the natural TMJ has a higher deformation value as compared to the patient-specific TMJ implant due to the lower mechanical strength of bone relative to the Ti-6Al-4V and Co-Cr alloy. Hence, we can conclude that the designed custom TMJ implant is safe for the patient from the point of design perspective.

Compared to traditional manufacturing methods, additive manufacturing and 3D printing stand out in their ability to rapidly fabricate complex structures and precise geometries. The growing need for products with different designs, purposes and materials led to the development of 3D printing, serving as a driving force for the 4th industrial revolution and digitization of manufacturing. 3D printing has had a global impact on healthcare, with patient-customized implants now replacing generic implantable medical devices. This revolution has had a particularly significant impact on oral and maxillofacial surgery, where surgeons rely on precision medicine in everyday practice. Trauma, orthognathic surgery and total joint replacement therapy represent several examples of treatments improved by 3D technologies. The widespread and rapid implementation of 3D technologies in clinical settings has led to the development of point-of-care treatment facilities with in-house infrastructure, enabling surgical teams to participate in the 3D design and manufacturing of devices. 3D technologies have had a tremendous impact on clinical outcomes and on the way clinicians approach treatment planning. The current review offers our perspective on the implementation of 3D-based technologies in the field of oral and maxillofacial surgery, while indicating major clinical applications. Moreover, the current report outlines the 3D printing point-of-care concept in the field of oral and maxillofacial surgery.

ObjectiveTo determine the accuracy of maxillary positioning using computer-designed and manufactured occlusal splints or patient-specific implants in orthognathic surgery.Material and MethodsA retrospective analysis of 28 patients that underwent virtually planned orthognathic surgery with maxillary Le Fort I osteotomy either using VSP-generated splints (n = 13) or patient-specific implants (PSI) (n = 15) was conducted. The accuracy and surgical outcome of both techniques were compared by superimposing preoperative surgical planning with postoperative CT scans and measurement of translational and rotational deviation for each patient.ResultsThe 3D global geometric deviation between the planned position and the postoperative outcome was 0.60 mm (95%-CI 0.46–0.74, range 0.32–1.11 mm) for patients with PSI and 0.86 mm (95%-CI 0.44–1.28, range 0.09–2.60 mm) for patients with surgical splints.Postoperative differences for absolute and signed single linear deviations between planned and postoperative position were a little higher regarding the x-axis and pitch but lower regarding the y- and z-axis as well as yaw and roll for PSI compared to surgical splints.There were no significant differences regarding global geometric deviation, absolute and signed linear deviations in the x-, y-, and z-axis, and rotations (yaw, pitch, and roll) between both groups.ConclusionsRegarding accuracy for positioning of maxillary segments after Le Fort I osteotomy in orthognathic surgery patient-specific implants and surgical splints provide equivalent high accuracy.Clinical relevancePatient-specific implants for maxillary positioning and fixation facilitate the concept of splintless orthognathic surgery and can be reliably used in clinical routines.

BackgroundManual moulding of cranioplasty implants after craniectomy is feasible, but does not always yield satisfying cosmetic results. In contrast, 3D printing can provide precise templates for intraoperative moulding of polymethylmethacrylate (PMMA) implants in cranioplasty. Here, we present a novel and easily implementable 3D printing workflow to produce patient-specific, sterilisable templates for PMMA implant moulding in cranioplastic neurosurgery.Methods3D printable templates of patients with large skull defects before and after craniectomy were designed virtually from cranial CT scans. Both templates — a mould to reconstruct the outer skull shape and a ring representing the craniectomy defect margins — were printed on a desktop 3D printer with biocompatible photopolymer resins and sterilised after curing. Implant moulding and implantation were then performed intraoperatively using the templates. Clinical and radiological data were retrospectively analysed.ResultsSixteen PMMA implants were performed on 14 consecutive patients within a time span of 10 months. The median defect size was 83.4 cm2 (range 57.8–120.1 cm2). Median age was 51 (range 21–80) years, and median operating time was 82.5 (range 52–152) min. No intraoperative complications occurred; PMMA moulding was uneventful and all implants fitted well into craniectomy defects. Excellent skull reconstruction could be confirmed in all postoperative computed tomography (CT) scans. In three (21.4%) patients with distinct risk factors for postoperative haematoma, revision surgery for epidural haematoma had to be performed. No surgery-related mortality or new and permanent neurologic deficits were recorded.ConclusionOur novel 3D printing-aided moulding workflow for elective cranioplasty with patient-specific PMMA implants proved to be an easily implementable alternative to solely manual implant moulding. The “springform” principle, focusing on reconstruction of the precraniectomy skull shape and perfect closure of the craniectomy defect, was feasible and showed excellent cosmetic results. The proposed method combines the precision and cosmetic advantages of computer-aided design (CAD) implants with the cost-effectiveness of manually moulded PMMA implants.

Patient-specific implants offer a host of benefits over their generic counterparts. Nonetheless, the design and optimization of these components present several technical challenges, among them being the need to ensure their insertability into the host bone tissue. This presents a significant challenge due to the tight-fitting nature of the bone-implant interface. This paper presents a novel insertability metric designed to efficiently assess whether a rigid body can be inserted into a tight-fitting cavity, without interference. In contrast to existing solutions, the metric is fully differentiable and can be incorporated as a design constraint into shape optimization routines. By exploiting the tight-fitting condition, the problem of planning an interference-free insertion path is reformulated as the search for a single interference-free movement, starting from the inserted configuration. We prove that if there exists any outward movement for which no interference is indicated, then the body can be fully extracted from or, equivalently, inserted into the cavity. This formulation is extremely efficient and highly robust with respect to the complexity of the geometry. We demonstrate the effectiveness and efficiency of our method by applying it to the optimization of two-dimensional (2D) and three-dimensional (3D) designs for insertability, subject to various design requirements. We then incorporate the proposed metric into the optimization of an acetabular cup used in total hip replacement (THR) surgery where geometric and structural requirements are considered.