Rapid high-fidelity contour shaping of titanium mesh implants for cranioplasty defects using patient-specific molds created with low-cost 3D printing: A case series

Single-Session Surgical Intervention with Resection of a Primary Cranial Osteosarcoma and Cranioplasty using a 3D-Printed Craniotomy Template and Cranioplasty Molds

Although osteosarcomas are the most frequent primary malignant bone tumors, the primary cranial manifestation of this condition is very rare with only a limited number of cases presented in the literature. We present the case of a 20-year-old male patient who underwent single-session surgical intervention for resection of right frontal osteosarcoma with a tailor-made craniotomy and cranioplasty using virtually designed 3D-printed templates and molds. Subsequently, the patient was treated according to the EURAMOS protocol and received adjuvant systemic chemotherapy. At 18-month follow-up, the patient was clinically asymptomatic, and both the magnetic resonance imaging scan of the head and the staging computed tomography showed no signs of tumor recurrence or metastases. The case presented shows that the use of 3D-printed molds facilitate a safe preoperative planning of the resection area and a single-session surgery including a custom-made cranioplasty responding to the highest esthetical standards.

Clinical study on the application effect of improved polyetheretherketone cranial plate in cranioplasty

This study evaluates the clinical outcomes associated with the use of an improved polyetheretherketone (PEEK) cranial plate in cranioplasty surgery. A total of 104 patients were involved, with significant findings revealing a reduced incidence of postoperative adverse reactions in the improved PEEK group (28.85%) compared to the conventional PEEK group (50.00%, P = 0.027). Patient satisfaction rates were markedly higher in the improved PEEK cohort (P < 0.05). Although the medical expenses for the enhanced PEEK group were greater (¥ 144 600 ± 21 200 vs ¥ 127 400 ± 20 100, P < 0.05), there were no notable differences in cerebral blood flow perfusion or survival time between the two groups (P > 0.05). The conclusions indicate that while the enhanced PEEK cranial plates incur higher upfront costs, their benefits in terms of safety and patient satisfaction, along with improved implant stability and bone healing, support their use in clinical practice. Consequently, the upgraded PEEK material is recommended for cranioplasty procedures.

Combining Patient-specific Implant With Malar Reduction to Repair Mid-facial Asymmetry Caused by Craniofacial Fractures in Asians

Mid-facial asymmetry caused by bone defect or deformation resulted from craniofacial fracture was a common secondary complication needed to repair. Patient-specific implant (PSI) designed with the unaffected side as a template is a good choice to repair this kind of facial asymmetry. However, in Asians, the broad and prominent zygomatic bone in unaffected side is not an optimal template, because the oval facial shape was considered as a more attractive appearance in Asian esthetic concept. To repair the mid-facial asymmetry and to improve the facial contour, the authors combined PSI implantation with malar reduction in one-stage surgery. The authors referred the facial proportion index (the optimal ratio of mid and lower face was 1.27) as a basis for preoperative precise design to determine the ideal facial shape of unaffected side, and used mirror image overlay technique with the ideal shape of unaffected side as a template to design the PSI. With this surgical strategy, patients not only can repair facial asymmetry but also can get a more attractive appearance.

Customized Additive Manufacturing in Bone Scaffolds-The Gateway to Precise Bone Defect Treatment

In the advancing landscape of technology and novel material development, additive manufacturing (AM) is steadily making strides within the biomedical sector. Moving away from traditional, one-size-fits-all implant solutions, the advent of AM technology allows for patient-specific scaffolds that could improve integration and enhance wound healing. These scaffolds, meticulously designed with a myriad of geometries, mechanical properties, and biological responses, are made possible through the vast selection of materials and fabrication methods at our disposal. Recognizing the importance of precision in the treatment of bone defects, which display variability from macroscopic to microscopic scales in each case, a tailored treatment strategy is required. A patient-specific AM bone scaffold perfectly addresses this necessity. This review elucidates the pivotal role that customized AM bone scaffolds play in bone defect treatment, while offering comprehensive guidelines for their customization. This includes aspects such as bone defect imaging, material selection, topography design, and fabrication methodology. Additionally, we propose a cooperative model involving the patient, clinician, and engineer, thereby underscoring the interdisciplinary approach necessary for the effective design and clinical application of these customized AM bone scaffolds. This collaboration promises to usher in a new era of bioactive medical materials, responsive to individualized needs and capable of pushing boundaries in personalized medicine beyond those set by traditional medical materials.

Late Frontal Bone Reconstruction Using Three-Dimensional Printed Models for Titanium Mesh Customization: A Case Series

BACKGROUND

The convex frontal bone is covered by thin skin, rendering its reconstruction cosmetically challenging. Customized alloplastic implants provide better contouring than autologous bone, yet their high cost and availability limit their application. We assess customized titanium mesh implants precontoured using patient-specific three-dimensional (3D) printed models for late frontal cranioplasty.

METHODS

We retrospectively analyzed the prospectively collected cases of unilateral frontal titanium mesh cranioplasty with 3D printing-assisted preplanning from 2017 to 2019. We used two 3D-printed patient-specific skull models for preoperative planning: a mirrored normal model for implant contouring and a defect model for edge trimming and fixation planning. The endoscope was used in 4 cases for percutaneous mesh fixation. We documented postoperative complications. We assessed the reconstruction symmetry clinically, and radiologically on postoperative computed tomography.

RESULTS

Fifteen patients were included. The duration after previous surgery ranged from 8 to 24 months. Four patients developed complications, which were managed conservatively. Favorable cosmetic outcomes were achieved in all patients.

CONCLUSIONS

Precontouring of titanium mesh implants using in-house 3D-printed models could optimize cosmetic and surgical outcomes in late frontal cranioplasty. Preoperative planning could permit minimal access surgery, which could be aided by the endoscope in select cases.

Next-generation personalized cranioplasty treatment

Decompressive craniectomy (DC) is a surgical procedure, that is followed by cranioplasty surgery. DC is usually performed to treat patients with traumatic brain injury, intracranial hemorrhage, cerebral infarction, brain edema, skull fractures, etc. In many published clinical case studies and systematic reviews, cranioplasty surgery is reported to restore cranial symmetry with good cosmetic outcomes and neurophysiologically relevant functional outcomes in hundreds of patients. In this review article, we present a number of key issues related to the manufacturing of patient-specific implants, clinical complications, cosmetic outcomes, and newer alternative therapies. While discussing alternative therapeutic treatments for cranioplasty, biomolecules and cellular-based approaches have been emphasized. The current clinical practices in the restoration of cranial defects involve 3D printing to produce patient-specific prefabricated cranial implants, that provide better cosmetic outcomes. Regardless of the advancements in image processing and 3D printing, the complete clinical procedure is time-consuming and requires significant costs. To reduce manual intervention and to address unmet clinical demands, it has been highlighted that automated implant fabrication by data-driven methods can accelerate the design and manufacturing of patient-specific cranial implants. The data-driven approaches, encompassing artificial intelligence (machine learning/deep learning) and E-platforms, such as publicly accessible clinical databases will lead to the development of the next generation of patient-specific cranial implants, which can provide predictable clinical outcomes. STATEMENT OF SIGNIFICANCE: Cranioplasty is performed to reconstruct cranial defects of patients who have undergone decompressive craniectomy. Cranioplasty surgery improves the aesthetic and functional outcomes of those patients. To meet the clinical demands of cranioplasty surgery, accelerated designing and manufacturing of 3D cranial implants are required. This review provides an overview of biomaterial implants and bone flap manufacturing methods for cranioplasty surgery. In addition, tissue engineering and regenerative medicine-based approaches to reduce clinical complications are also highlighted. The potential use of data-driven computer applications and data-driven artificial intelligence-based approaches are emphasized to accelerate the clinical protocols of cranioplasty treatment with less manual intervention and shorter intraoperative time.

Low-Cost Cranioplasty-A Systematic Review of 3D Printing in Medicine

The high cost of biofabricated titanium mesh plates can make them out of reach for hospitals in low-income countries. To increase the availability of cranioplasty, the authors of this work investigated the production of polymer-based endoprostheses. Recently, cheap, popular desktop 3D printers have generated sufficient opportunities to provide patients with on-demand and on-site help. This study also examines the technologies of 3D printing, including SLM, SLS, FFF, DLP, and SLA. The authors focused their interest on the materials in fabrication, which include PLA, ABS, PET-G, PEEK, and PMMA. Three-dimensional printed prostheses are modeled using widely available CAD software with the help of patient-specific DICOM files. Even though the topic is insufficiently researched, it can be perceived as a relatively safe procedure with a minimal complication rate. There have also been some initial studies on the costs and legal regulations. Early case studies provide information on dozens of patients living with self-made prostheses and who are experiencing significant improvements in their quality of life. Budget 3D-printed endoprostheses are reliable and are reported to be significantly cheaper than the popular counterparts manufactured from polypropylene polyester.

Adaptive Mechanism for Designing a Personalized Cranial Implant and Its 3D Printing Using PEEK

The rehabilitation of the skull's bones is a difficult process that poses a challenge to the surgical team. Due to the range of design methods and the availability of materials, the main concerns are the implant design and material selection. Mirror-image reconstruction is one of the widely used implant reconstruction techniques, but it is not a feasible option in asymmetrical regions. The ideal design approach and material should result in an implant outcome that is compact, easy to fit, resilient, and provides the perfect aesthetic and functional outcomes irrespective of the location. The design technique for the making of the personalized implant must be easy to use and independent of the defect's position on the skull. As a result, this article proposes a hybrid system that incorporates computer tomography acquisition, an adaptive design (or modeling) scheme, computational analysis, and accuracy assessment. The newly developed hybrid approach aims to obtain ideal cranial implants that are unique to each patient and defect. Polyetheretherketone (PEEK) is chosen to fabricate the implant because it is a viable alternative to titanium implants for personalized implants, and because it is simpler to use, lighter, and sturdy enough to shield the brain. The aesthetic result or the fitting accuracy is adequate, with a maximum deviation of 0.59 mm in the outside direction. The results of the biomechanical analysis demonstrate that the maximum Von Mises stress (8.15 MPa), Von Mises strain (0.002), and deformation (0.18 mm) are all extremely low, and the factor of safety is reasonably high, highlighting the implant's load resistance potential and safety under high loading. Moreover, the time it takes to develop an implant model for any cranial defect using the proposed modeling scheme is very fast, at around one hour. This study illustrates that the utilized 3D reconstruction method and PEEK material would minimize time-consuming alterations while also improving the implant's fit, stability, and strength.

Cranioplasty Using Customized 3-Dimensional-Printed Titanium Implants: An International Collaboration Effort to Improve Neurosurgical Care

BACKGROUND

Evolutions in cranioplasty have allowed for the creation of customized implants via advances in 3-dimensional (3D) printing technology, although the high cost associated with this technique presents a barrier for low-income countries. Through an international collaboration, our team in Da Nang, Vietnam is able to create low-cost, customized titanium implants for patients with skull defects. We discuss the details of our collaboration and present our experience with this procedure.

METHODS

We conducted a retrospective review of 35 patients who underwent cranioplasty using custom-made titanium implants. The molding and implant making processes were performed by our neurosurgeons using a 3D printer donated by the United Kingdom-based nongovernmental organization Facing the World. We obtained demographic and preoperative data (reason for skull defect, location, surface area measurement of defect) and postoperative data (complications, cosmetic outcome, and patient satisfaction).

RESULTS

The median patient age was 27 years (range, 16-60 years). Primary indications for craniectomy included traumatic brain injury from motor vehicle accident (77.1%), cerebrovascular disease (11.4%), implant failure following previous cranioplasty (5.7%), and fall (5.7%). Postoperatively, all implants were found to have an excellent fit; at 6-month follow-up, none of the implants required removal. Complications included 4 postoperative hematomas and 1 surgical site infection. All the patients had improved aesthetic appearance and high satisfaction.

CONCLUSIONS

Cranioplasty using customized titanium implants yields excellent results for patients with skull defects, demonstrating the practicality of this technique for cranioplasty in low-income countries. Our experience highlights the importance of ongoing international collaboration to improve neurosurgical care in these countries.