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Adult, Biocompatible Materials economics, Computer-Aided Design, Female, Humans, Male, Middle Aged, Perioperative Period, Polymethyl Methacrylate economics, Biocompatible Materials therapeutic use, Polymethyl Methacrylate therapeutic use, Prostheses and Implants economics, Prosthesis Design economics, Reconstructive Surgical Procedures methods, and Skull surgery

Polymethyl methacrylate (PMMA), an easily moldable and economical synthetic resin, has been used since the 1940s. In addition, PMMA has good mechanical properties and is one of the most biocompatible alloplastic materials currently available. The PMMA can serve as a spacer and as a delivery vehicle for antibiotics. Prior studies have indicated that no significant differences in infection rates exist between autologous and acrylic cranioplasty. Although inexpensive, the free-hand cranioplasty technique often yields unsatisfactory cosmetic results. In the present study, the application of a recently developed, economic modality for the perioperative application, and molding of PMMA to ensure a precise fit in 16 patients using computer-aided design, computer-aided manufacturing, and rapid prototyping was described.The mean defect size was 102.0 ± 26.4 cm. The mean volume of PMMA required to perform the cranioplasty procedure was 51 mL. The cost of PMMA was approximately 6 Euro (&OV0556;) per mL. The costs of fabricating the implants varied from 119.8 &OV0556; to 1632.0 &OV0556; with a mean of 326.4 &OV0556; ± 371.6. None of the implants required removal during the follow-up period.

Adolescent, Adult, Aged, Child, Child, Preschool, Craniofacial Abnormalities surgery, Esthetics, Female, Fibrous Dysplasia of Bone surgery, Humans, Male, Middle Aged, Models, Anatomic, Skull Base surgery, Skull Neoplasms surgery, Time Factors, Treatment Outcome, Computer-Aided Design, Neurosurgical Procedures, Patient Care Planning, Prostheses and Implants, Prosthesis Design, Reconstructive Surgical Procedures, and Skull surgery

The value of rapid prototype models of the skull in our craniofacial and neurosurgical practice was analyzed. Individual skull models of 52 patients were produced by means of rapid prototyping techniques and used in various procedures. Patients were divided into three groups as follows: group I (26 patients) requiring corrective cranioplasty 1) after resection of osseous tumors (15 patients) and 2) with congenital and posttraumatic craniofacial deformities (11 patients), group II (10 patients) requiring reconstructive cranioplasty, and group III (16 patients) requiring planning of difficult skull base approaches. The utility of the stereolithographic models was assessed using the Gillespie scoring system. The esthetic and clinical outcomes were assessed by means of the esthetic outcome score and the Glasgow Outcome Score, respectively. Simulation of osteotomies for advancement plasty and craniofacial reassembly in the model before surgery in group I reduced operating time and intraoperative errors. In group II, the usefulness of the models depended directly on the size and configuration of the cranial defect. The planning of approaches to uncommon and complex skull base tumors (group III) was significantly influenced by the stereolithographic models. The esthetic outcome was pleasing. The indications for the manufacture of individual three-dimensional models could be cases of craniofacial dysmorphism that require meticulous preoperative planning and skull base surgery with difficult anatomical and reconstructive problems. The stereolithographic models provide 1) better understanding of the anatomy, 2) presurgical simulation, 3) intraoperative accuracy in localization of lesions, 4) accurate fabrication of implants, and 5) improved education of trainees.

Cost Control, Esthetics, Humans, Image Processing, Computer-Assisted economics, Prosthesis Fitting, Surface Properties, Bone Plates, Computer-Aided Design economics, Image Processing, Computer-Assisted methods, Prostheses and Implants, Prosthesis Design, Skull surgery, Titanium, and Tomography, X-Ray Computed methods

This report describes a new method of custom making cranial titanium plates for the repair of skull defects. We have combined 3D CT imaging and surface modelling with rapid prototyping (RP) technology to produce physical models of our patients' skulls from which custom titanium plates were made. We have expanded the use of image processing tools applied to the CT image data to fabricate a representation of the skull defect. Medical RP models are relatively expensive and particular attention has been paid to developing image processing methods to reduce costs. Our technique used the patient as their own model and generated data from the contralateral side of the head where appropriate. We present the results of 10 patients who have had a custom made cranial titanium plate fitted and discuss the models for these cases. The benefits of our custom made titanium plates are reduced patient attendances to hospital and a more accurate titanium plate which has improved fitting and cosmesis.

Craniotomy, Lasers, Prostheses and Implants, Prosthesis Design, and Skull surgery

This article compared the accuracy of producing patient-specific cranioplasty implants using four different approaches. Benchmark geometry was designed to represent a cranium and a defect added simulating a craniectomy. An 'ideal' contour reconstruction was calculated and compared against reconstructions resulting from the four approaches -'conventional', 'semi-digital', 'digital - non-automated' and 'digital - semi-automated'. The 'conventional' approach relied on hand carving a reconstruction, turning this into a press tool, and pressing titanium sheet. This approach is common in the UK National Health Service. The 'semi-digital' approach removed the hand-carving element. Both of the 'digital' approaches utilised additive manufacturing to produce the end-use implant. The geometries were designed using a non-specialised computer-aided design software and a semi-automated cranioplasty implant-specific computer-aided design software. It was found that all plates were clinically acceptable and that the digitally designed and additive manufacturing plates were as accurate as the conventional implants. There were no significant differences between the additive manufacturing plates designed using non-specialised computer-aided design software and those designed using the semi-automated tool. The semi-automated software and additive manufacturing production process were capable of producing cranioplasty implants of similar accuracy to multi-purpose software and additive manufacturing, and both were more accurate than handmade implants. The difference was not of clinical significance, demonstrating that the accuracy of additive manufacturing cranioplasty implants meets current best practice.

Child, Computer-Aided Design, Craniofacial Abnormalities diagnostic imaging, Humans, Male, Prosthesis Design, Radiography, Skull diagnostic imaging, Craniofacial Abnormalities surgery, Methylmethacrylate, Prostheses and Implants, Reconstructive Surgical Procedures methods, and Skull surgery

The desired features of a cranioplast include providing an acceptable contour, continuity with the remaining skull (marginal adaptation), improvising the aesthetic outcome, providing a strengthened prosthesis to avoid fracture in case of repeat trauma, and protecting the remaining neurological structures. Combining digital and manual techniques to fabricate a hybrid polymethylmethacrylate cranioplast during the rehabilitation of a pediatric patient with cranial defect has been described. Utilization of digital techniques (rapid prototyping to obtain skull analog) and manual (hand) sculpting of the prosthesis strengthened with glass fiber enabled the authors to fabricate a hybrid cranioplast. Satisfactory outcome was achieved.

Adult, Algorithms, Computer-Aided Design, Female, Humans, Reproducibility of Results, Sensitivity and Specificity, Skull abnormalities, Imaging, Three-Dimensional methods, Prostheses and Implants, Prosthesis Fitting methods, Radiographic Image Interpretation, Computer-Assisted methods, Skull diagnostic imaging, Skull surgery, and Tomography, X-Ray Computed methods

Skull defect reconstruction is an important aspect of surgical repair. Historically, a skull defect prosthesis was created by the mirroring technique, surface fitting, or formed templates. These methods are not based on the anatomy of the individual patient's skull, and therefore, the prosthesis cannot precisely correct the defect. This study presented a new hybrid level set model, taking into account both the global optimization region information and the local accuracy edge information, while avoiding re-initialization during the evolution of the level set function. Based on the new method, a skull defect was reconstructed, and the skull prosthesis was produced by rapid prototyping technology. This resulted in a skull defect prosthesis that well matched the skull defect with excellent individual adaptation.

Humans, Biomedical Engineering methods, Bone Resorption surgery, Computer-Aided Design, Craniotomy adverse effects, Prostheses and Implants, Reconstructive Surgical Procedures methods, and Skull

Background: Most patients with large focal skull bone loss after craniectomy are referred for cranioplasty. Reverse engineering is a technology which creates a computer-aided design (CAD) model of a real structure. Rapid prototyping is a technology which produces physical objects from virtual CAD models. The aim of this study was to assess the clinical usefulness of these technologies in cranioplasty prosthesis manufacturing.
Material/methods: CT was performed on 19 patients with focal skull bone loss after craniectomy, using a dedicated protocol. A material model of skull deficit was produced using computer numerical control (CNC) milling, and individually pre-operatively adjusted polypropylene-polyester prosthesis was prepared. In a control group of 20 patients a prosthesis was manually adjusted to each patient by a neurosurgeon during surgery, without using CT-based reverse engineering/rapid prototyping. In each case, the prosthesis was implanted into the patient. The mean operating times in both groups were compared.
Results: In the group of patients with reverse engineering/rapid prototyping-based cranioplasty, the mean operating time was shorter (120.3 min) compared to that in the control group (136.5 min). The neurosurgeons found the new technology particularly useful in more complicated bone deficits with different curvatures in various planes.
Conclusions: Reverse engineering and rapid prototyping may reduce the time needed for cranioplasty neurosurgery and improve the prosthesis fitting. Such technologies may utilize data obtained by commonly used spiral CT scanners. The manufacturing of individually adjusted prostheses should be commonly used in patients planned for cranioplasty with synthetic material.

Accidental Falls, Child, Female, Humans, Prosthesis Design, Prostheses and Implants, Skull injuries, and Skull surgery

In a pediatric patient with cranial defect, in order to replace the missing portion of the cranium, an acrylic cranial implant was fabricated prior to the surgical procedure. The primary aim was to fabricate this cranial implant prior to the surgical procedure and with optimum fit. A customized hand-sculpted acrylic cranial implant fabricated by lost wax technique was made prior to the surgery and with adequate precision.The prefabricated cranial implant was used by neurosurgeons on the patient in order to restore the continuity of bone (by the acrylic cranioplast) over the cranial defect, improving the aesthetics and more importantly providing protection to the vital neural tissue.Though with recent advancements (like computer-aided design and manufacturing, and rapid prototyping), rapidity and precision can be achieved in the fabrication of cranial prosthesis, yet most of the apparatus may not be amenable in every setup and may not be affordable by all patients. A simple, operator-friendly technique which acquires satisfactory precision has been described for a patient much in need. Optimal postoperatory results were attained.