Custom-made cast titanium implants produced with CAD/CAM for the reconstruction of cranium defects

Patient-Specific Implants (PSI) in Maxillary Hypoplasia Secondary to Cleft Lip and Palate Deformity

Maxillary hypoplasia is often evident in cleft patients due to impaired growth and dense scarring from previous cleft surgeries. For these patients, treatment scenario has taken many turns over ages, evolved from orthognathic correction to distraction osteogenesis, with mixed prognosis and outcome depending on severity of the case and other several factors. We are reporting a case of 24-year-old female with maxillary hypoplasia secondary to bilateral cleft lip and palate with hypoplastic prolabium, who has been treated with two patient-specific implants in bilateral maxillary region for facial profile enhancement.

Reconstruction of the Occipital and Parietal Congenital Defect with 3D Custom-Made Titanium Prosthesis: A Case Report with Four and a Half Years of Follow-Up and a Brief Review of Literature

Management of patients with congenital skull defects requires a multidisciplinary approach. Considering the defect's location and size, brain protection, and the cosmetic outcome makes such reconstructions challenging. Due to limited resemblance to skull contour and donor site morbidity of autogenous bone grafts, alloplastic materials are widely used for skull reconstructions. Titanium alloys have proper strength values, low infection rates, favorable osseointegration property, and excellent marginal adaptability when manufactured by computer-aided design (CAD) and computer-aided manufacturing (CAM). A 13-year-old female patient presented with congenital defects at the superior third of occipital bone and posterior thirds of the bilateral parietal bones. On CT scan, the exact size and shape of the defect were determined. Using CAD/CAM, a 3D virtual model of the prosthesis was designed and then printed with titanium alloy (TiAl6V4) via additive manufacturing method. The prosthesis was placed on the defect in a total surgery time of only 90 minutes. On 4.5 years of follow-up, the contour of the skull was ideal and the skin over the defect and neurologic status was intact. Due to their biocompatibility and rigidity, custom-made titanium prostheses are promising options for reconstructing complex skull defects.

Facial Reconstruction: A Systematic Review of Current Image Acquisition and Processing Techniques

Introduction: Plastic and reconstructive surgery is based on a culmination of technological advances, diverse techniques, creative adaptations and strategic planning. 3D imaging is a modality that encompasses several of these criteria while encouraging the others. Imaging techniques used in facial imaging come in many different modalities and sub-modalities which is imperative for such a complex area of the body; there is a clear clinical need for hyper-specialized practice. However, with this complexity comes variability and thus there will always be an element of bias in the choices made for imaging techniques. Aims and Objectives: The aim of this review is to systematically analyse the imaging techniques used in facial reconstruction and produce a comprehensive summary and comparison of imaging techniques currently available, including both traditional and novel methods. Methods: The systematic search was performed on EMBASE, PubMed, Scopus, Web of Science and Cochrane reviews using keywords such as "image technique/acquisition/processing," "3-Dimensional," "Facial," and "Reconstruction." The PRISMA guidelines were used to carry out the systematic review. Studies were then subsequently collected and collated; followed by a screening and exclusion process with a final full-text review for further clarification in regard to the selection criteria. A risk of bias assessment was also carried out on each study systematically using the respective tool in relation to the study in question. Results: From the initial 6,147 studies, 75 were deemed to fulfill all selection criteria and selected for meta-analysis. The majority of papers involved the use of computer tomography, though the use of magnetic resonance and handheld scanners using sonography have become more common in the field. The studies ranged in patient population, clinical indication. Seminal papers were highlighted within the group of papers for further analysis. Conclusions: There are clearly many factors that affect the choice of image acquisition techniques and their potential at being ideal for a given role. Ultimately the surgical team's choice will guide much of the decision, but it is crucial to be aware of not just the diagnostic ability of such modalities, but their treatment possibilities as well.

Optimizing Manufacturing and Osseointegration of Ti6Al4V Implants through Precision Casting and Calcium and Phosphorus Ion Implantation? In Vivo Results of a Large-Scale Animal Trial

Background: Uncemented implants are still associated with several major challenges, especially with regard to their manufacturing and their osseointegration. In this study, a novel manufacturing technique—an optimized form of precision casting—and a novel surface modification to promote osseointegration—calcium and phosphorus ion implantation into the implant surface—were tested in vivo. Methods: Cylindrical Ti6Al4V implants were inserted bilaterally into the tibia of 110 rats. We compared two generations of cast Ti6Al4V implants (CAST 1st GEN, n = 22, and CAST 2nd GEN, n = 22) as well as cast 2nd GEN Ti6Al4V implants with calcium (CAST + CA, n = 22) and phosphorus (CAST + P, n = 22) ion implantation to standard machined Ti6Al4V implants (control, n = 22). After 4 and 12 weeks, maximal pull-out force and bone-to-implant contact rate (BIC) were measured and compared between all five groups. Results: There was no significant difference between all five groups after 4 weeks or 12 weeks with regard to pull-out force (p > 0.05, Kruskal Wallis test). Histomorphometric analysis showed no significant difference of BIC after 4 weeks (p > 0.05, Kruskal–Wallis test), whereas there was a trend towards a higher BIC in the CAST + P group (54.8% ± 15.2%), especially compared to the control group (38.6% ± 12.8%) after 12 weeks (p = 0.053, Kruskal–Wallis test). Conclusion: In this study, we found no indication of inferiority of Ti6Al4V implants cast with the optimized centrifugal precision casting technique of the second generation compared to standard Ti6Al4V implants. As the employed manufacturing process holds considerable economic potential, mainly due to a significantly decreased material demand per implant by casting near net-shape instead of milling away most of the starting ingot, its application in manufacturing uncemented implants seems promising. However, no significant advantages of calcium or phosphorus ion implantation could be observed in this study. Due to the promising results of ion implantation in previous in vitro and in vivo studies, further in vivo studies with different ion implantation conditions should be considered.

Single-Step Resection of Sphenoorbital Meningiomas and Orbital Reconstruction Using Customized CAD/CAM Implants

Objective  Computer-aided design and manufacturing (CAD/CAM) implants are fabricated based on volumetric analysis of computed tomography (CT) scans and are routinely used for the reconstruction of orbital fractures. We present three cases of patients with sphenoorbital meningiomas that underwent tumor resection, orbital decompression, and orbital reconstruction with patient specific porous titanium or acrylic implants in a single procedure. Methods  The extent of bone resection of the sphenoorbital meningiomas was planned in a virtual three-dimensional (3D) environment using preoperative thin-layer CT data. The anatomy of the orbital wall in the resection area was reconstructed by superimposing the contralateral unaffected orbit and by using the information of the neighboring bony structures. The customized implants and a corresponding craniotomy template were designed in the desired size and shape by the manufacturer. Results  All patients presented with a sphenoorbital meningioma and exophthalmos. After osteoclastic craniotomy with the drilling template, orbital decompression was performed. Implant fitting was tight in two cases and could be easily fixated with miniplates and screws. In the third patient, a reoperation was necessary for additional bone resection, as well as drilling and repositioning of the implant. The postoperative CT scans showed an accurate reconstruction of the orbital wall. After surgery, exophthalmos was substantially reduced and a satisfying cosmetic result could be finally achieved in all patients. Conclusions  The concept of preoperative 3D virtual treatment planning and single-step orbital reconstruction with CAD/CAM implants after tumor resection involving the orbit is well feasible and can lead to good cosmetic results.

A novel economically viable solution for 3D printing-assisted cranioplast fabrication

Cranioplasty is a common neurosurgical procedure which makes use of autologous bone or alloplastic material for cranial defect reconstruction. Alloplastic reconstruction is routinely done in cases where viable autologous bone is not available due to various reasons. Hydroxyapatite implants, patient-specific titanium and PEEK are widely employed materials due to their biocompatibility, durability, and high adaptation accuracy. However, their high cost and limited availability make them a less viable option for the common man. Polymethyl methacrylate (PMMA) is one of the commonly used alloplastic material for cranioplasty. This note presents a novel, economic, patient-specific, 3D printing-assisted and heat polymerized PMMA cranioplast fabrication technique with an accuracy comparable to that of patient-specific titanium and PEEK cranioplast.

Present and future for technologies to develop patient-specific medical devices: a systematic review approach

The main purpose of this investigation was to systematically review the literature regarding case studies on patient-specific implants and devices, with the goal of analyzing the process of developing custom-made medical devices. A content analysis was performed to identify design processes and methodologies implemented to develop devices such as implants adapted to bone geometries. Reverse engineering, computer-aided design, simulation of assets, and rapid prototyping technologies were selected according to their interoperability in a process framework for developing new products. Finally, results from the case studies and process stages identified in the consulted research were analyzed. These results showed a relationship between the scope and complexity of the process and the stage of technology integration of the patient-specific device development. The analyzed case studies were characterized by technical, scientific, and multidisciplinary components to achieve research goals. Likewise, integration of technologies using patient-specific technologies is needed for product development that converges into designing devices, such as implants, biomodels, and cutting drilling guides.

Living the heart in three dimensions: applications of 3D printing in CHD

Advances in biomedical engineering have led to three-dimensional (3D)-printed models being used for a broad range of different applications. Teaching medical personnel, communicating with patients and relatives, planning complex heart surgery, or designing new techniques for repair of CHD via cardiac catheterisation are now options available using patient-specific 3D-printed models. The management of CHD can be challenging owing to the wide spectrum of morphological conditions and the differences between patients. Direct visualisation and manipulation of the patients' individual anatomy has opened new horizons in personalised treatment, providing the possibility of performing the whole procedure in vitro beforehand, thus anticipating complications and possible outcomes. In this review, we discuss the workflow to implement 3D printing in clinical practice, the imaging modalities used for anatomical segmentation, the applications of this emerging technique in patients with structural heart disease, and its limitations and future directions.

Incremental Forming of Titanium Ti6Al4V Alloy for Cranioplasty Plates—Decision-Making Process and Technological Approaches

Ti6Al4V titanium alloy is considered a biocompatible material, suitable to be used for manufacturing medical devices, particularly cranioplasty plates. Several methods for processing titanium alloys are reported in the literature, each one presenting both advantages and drawbacks. A decision-making method based upon AHP (analytic hierarchy process) was used in this paper for choosing the most recommended manufacturing process among some alternatives. The result of AHP indicated that single-point incremental forming (SPIF) at room temperature could be considered the best approach when manufacturing medical devices. However, Ti6Al4V titanium alloy is known as a low-plasticity material when subjected to plastic deformation at room temperature, so special measures had to be taken. The experimental results of processing parts from Ti6Al4V titanium alloy by means of SPIF and technological aspects are considered.

Material Processing and Design of Biodegradable Metal Matrix Composites for Biomedical Applications

In recent years, biodegradable metallic materials have played an important role in biomedical applications. However, as typical for the metal materials, their structure, general properties, preparation technology and biocompatibility are hard to change. Furthermore, biodegradable metals are susceptible to excessive degradation and subsequent disruption of their mechanical integrity; this phenomenon limits the utility of these biomaterials. Therefore, the use of degradable metals, as the base material to prepare metal matrix composite materials, it is an excellent alternative to solve the problems above described. Biodegradable metals can thus be successfully combined with other materials to form biodegradable metallic matrix composites for biomedical applications and functions. The present article describes the processing methods currently available to design biodegradable metal matrix composites for biomedical applications and provides an overview of the current existing biodegradable metal systems. At the end, the manuscript presents and discusses the challenges and future research directions for development of biodegradable metallic matrix composites for biomedical purposes.

The effect of manufacturing techniques on custom-made titanium cranioplasty plates: A pilot study

OBJECTIVE

This study investigated the effect of varying techniques on the surface characteristics of pressed titanium cranioplasty plates, commonly manufactured in laboratory practice. The aim was to highlight the variety of techniques currently used, assess these methods of manufacture and produce manufacturing recommendations.

METHODS

A questionnaire identified manufacturing methods commonly used by maxillofacial prosthetists. The plate surfaces were examined using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectrometry. The surface differences and titanium compositions were statistically analysed.

RESULTS

Bead blasting with aluminium oxide (Al₂O₃) showed a significant decrease (p < 0.001) in titanium surface composition, replaced by a large aluminium content. Trimming tool choice had a significant impact (p = 0.001) on surface contamination by smoothing wheel material deposition; however passivation and anodising techniques had no significant effect (p = 0.293 and p = 0.257, respectively) on the surface composition or roughness of titanium samples.

CONCLUSIONS

A large range of manufacturing techniques of titanium cranioplasty plates was confirmed and significant differences were found. Amongst other recommendations, bead blasting with Al₂O₃ is not recommended for commercially pure titanium implant surface finishing due to aluminium contamination. The recommendations outlined will minimise manufacturing time, reduce risk of complication (thus costs) and unify methods to enable a safe, reliable treatment.

Customized Orbital Wall Reconstruction Using Three-Dimensionally Printed Rapid Prototype Model in Patients With Orbital Wall Fracture

BACKGROUND

It is difficult to restore original orbital contours because of their complex 3-dimensional structure. Moreover, slight implant malpositioning can result in enophthalmos or other complications. The authors describe our experience of using individualized prebent titanium-Medpor mesh implants and stereolithographic modeling in a series of patients who underwent orbital wall reconstruction.

METHODS

A consecutive series of 104 patients with orbital fractures received computer simulation-designed prebent titanium-Medpor mesh implants insertion. Preoperative computed tomography (CT) data were processed for each patient, and a rapid prototyping (RP) model was produced. The uninjured side was concurrently mirrored and superimposed onto the traumatized side to create a mirror image of the RP model. The authors fabricated the titanium-Medpor implants to intraoperatively reconstruct the 3-dimensional orbital structure. The prefabricated titanium-Medpor implants were inserted into the defective orbital wall and fixed. Postoperative CT images were immediately taken to evaluate the reconstructed contours and compare the preoperative and postoperative intraorbital volumes.

RESULTS

All reconstructions were successful without postoperative complications. The implants were correctly positioned in the sagittal, axial, and coronal planes relative to the original orbital contours. The mean preoperative intraorbital volumes of the uninjured and traumatized sides were 21.39 ± 1.93 and 23.17 ± 2.00 cm, respectively, and the postoperative mean intraorbital volume was 20.74 ± 2.07 cm.

CONCLUSIONS

Orbital reconstruction can be optimized using individually manufactured rapid prototype skull model and premolded synthetic scaffold by computer-aid of mirroring-reconstruction of 3-dimensional images and 3-dimensional printing techniques.

A Craniomaxillofacial Surgical Assistance Workstation for Enhanced Single-Stage Reconstruction Using Patient-Specific Implants

BACKGROUND

Craniomaxillofacial reconstruction with patient-specific, customized craniofacial implants (CCIs) is ideal for skeletal defects involving areas of aesthetic concern-the non-weight-bearing facial skeleton, temporal skull, and/or frontal-forehead region. Results to date are superior to a variety of "off-the-shelf" materials, but require a protocol computed tomography scan and preexisting defect for computer-assisted design/computer-assisted manufacturing of the CCI. The authors developed a craniomaxillofacial surgical assistance workstation to address these challenges and intraoperatively guide CCI modification for an unknown defect size/shape.

METHODS

First, the surgeon designed an oversized CCI based on his/her surgical plan. Intraoperatively, the surgeon resected the bone and digitized the resection using a navigation pointer. Next, a projector displayed the limits of the craniofacial bone defect onto the prefabricated, oversized CCI for the size modification process; the surgeon followed the projected trace to modify the implant. A cadaveric study compared the standard technique (n = 1) to the experimental technique (n = 5) using surgical time and implant fit.

RESULTS

The technology reduced the time and effort needed to resize the oversized CCI by an order of magnitude as compared with the standard manual resizing process. Implant fit was consistently better for the computer-assisted case compared with the control by at least 30%, requiring only 5.17 minutes in the computer-assisted cases compared with 35 minutes for the control.

CONCLUSION

This approach demonstrated improvement in surgical time and accuracy of CCI-based craniomaxillofacial reconstruction compared with previously reported methods. The craniomaxillofacial surgical assistance workstation will provide craniofacial surgeons a computer-assisted technology for effective and efficient single-stage reconstruction when exact craniofacial bone defect sizes are unknown.

Utility and Scope of Rapid Prototyping in Patients with Complex Muscular Ventricular Septal Defects or Double-Outlet Right Ventricle: Does it Alter Management Decisions?

Rapid prototyping facilitates comprehension of complex cardiac anatomy. However, determining when this additional information proves instrumental in patient management remains a challenge. We describe our experience with patient-specific anatomic models created using rapid prototyping from various imaging modalities, suggesting their utility in surgical and interventional planning in congenital heart disease (CHD). Virtual and physical 3-dimensional (3D) models were generated from CT or MRI data, using commercially available software for patients with complex muscular ventricular septal defects (CMVSD) and double-outlet right ventricle (DORV). Six patients with complex anatomy and uncertainty of the optimal management strategy were included in this study. The models were subsequently used to guide management decisions, and the outcomes reviewed. 3D models clearly demonstrated the complex intra-cardiac anatomy in all six patients and were utilized to guide management decisions. In the three patients with CMVSD, one underwent successful endovascular device closure following a prior failed attempt at transcatheter closure, and the other two underwent successful primary surgical closure with the aid of 3D models. In all three cases of DORV, the models provided better anatomic delineation and additional information that altered or confirmed the surgical plan. Patient-specific 3D heart models show promise in accurately defining intra-cardiac anatomy in CHD, specifically CMVSD and DORV. We believe these models improve understanding of the complex anatomical spatial relationships in these defects and provide additional insight for pre/intra-interventional management and surgical planning.

Binder-jetting 3D printing and alloy development of new biodegradable Fe-Mn-Ca/Mg alloys

3D printing of various biomaterials including titanium and stainless steel has been studied for treating patients with cranio-maxillofacial bone defect. The potential long term complications with use of inert biometals have opened the opportunities for use of biodegradable metals in the clinical arena. The authors previously reported that binder-jet 3D printing technique enhanced the degradation rates of biodegradable Fe-Mn alloy by creating engineered micropores rendering the system attractive as biodegradable implantable devices. In the present study, the authors employed CALPHAD modeling to systematically study and modify the Fe-Mn alloy composition to achieve enhanced degradation rates. Accordingly, Ca and Mg addition to Fe-35wt% Mn solid solution predicted increase in degradation rates. In order to validate the CALPHAD results, Fe - (35-y)wt% Mn - ywt% X (X=Ca, Mg, and y=0, 1, 2) were synthesized by using high energy mechanical alloying (HEMA). Sintered pellets of Fe-Mn-Ca and Fe-Mn-Mg were then subjected to potentiodynamic polarization (PDP) and live/dead cell viability tests. Sintered pellets of Fe-Mn, Fe-Mn-Ca, and Fe-Mn-Mg also exhibited MC3T3 murine pre-osteoblast cells viability in the live/dead assay results. Fe-Mn and Fe-Mn-1Ca were thus accordingly selected for 3D printing and the results further confirmed enhanced degradation of Ca addition to 3D printed constructs validating the theoretical and alloy development studies. Live/dead and MTT cell viability results also confirmed good cytocompatibility of the 3D-printed Fe-Mn and Fe-Mn-1Ca constructs.

STATEMENT OF SIGNIFICANCE

Bone grafting is widely used for the treatment of cranio-maxillofacial bone injuries. 3D printing of biodegradable Fe alloy is anticipated to be advantageous over current bone grafting techniques. 3D printing offers the fabrication of precise and tailored bone grafts to fit the patient specific bone defect needs. Biodegradable Fe alloy is a good candidate for 3D printing synthetic grafts to regenerate bone tissue without eliciting complications. CALPHAD theoretical models were used to develop new Fe-Mn-Ca/Mg alloys to enhance the degradation rates of traditional Fe-Mn alloys. In vitro experimental results also showed enhanced degradation rates and good cytocompatibility of sintered Fe-Mn-Ca/Mg compacts. 3D printing of Fe-Mn and Fe-Mn-1Ca alloys further demonstrated their feasibility as potentially viable bone grafts for the future.

Repair of segmental radial defects in dogs using tailor-made titanium mesh cages with plates combined with calcium phosphate granules and basic fibroblast growth factor-binding ion complex gel

Repair of large segmental defects of long bones are a tremendous challenge that calls for a novel approach to supporting immediate weight bearing and bone regeneration. This study investigated the functional and biological characteristics of a combination of a tailor-made titanium mesh cage with a plate (tTMCP) with tetrapod-shaped alpha tricalcium phosphate granules (TB) and basic fibroblast growth factor (bFGF)-binding ion complex gel (f-IC gel) to repair 20-mm segmental radial defects in dogs. The defects were created surgically in 18 adult beagle dogs and treated by implantation of tTMCPs with TB with (TB-gel group) or without (TB group) f-IC gel. Each tTMCP fitted the defect well, and all dogs could bear weight on the affected limb immediately after surgery. Dogs were euthanized 4, 8 and 24 weeks after implantation. Histomorphometry showed greater infiltration of new vessels and higher bone union rate in the TB-gel group than in the TB group. The lamellar bone volume and mineral apposition rate did not differ significantly between the groups, indicating that neovascularization may be the primary effect of f-IC gel on bone regeneration. This combination method which is tTMCP combined with TB and f-IC gel, would be useful for the treatment of segmental long bone defects.

Inflammatory response to implantation of transparent nanocrystalline yttria-stabilized zirconia using a dorsal window chamber model

The long-range goal of the windows to the brain (WttB) is to improve patient care by providing a technique for delivery and/or collection of light into/from the brain, on demand, over large areas, and on a chronically-recurring basis without the need for repeated craniotomies. To evaluate the potential of nanocrystalline yttria-stabilized-zirconia (nc-YSZ) cranial implant for optical therapy and imaging, in vivo biocompatibility was studied using the dorsal window chamber model in comparison with control (no implant) and commercially available cranial implant materials (PEEK and PEKK). The host tissue response to implant was characterized by using transillumination and fluorescent microscopy to measure leukocyte adhesion, blood vessel diameter, blood flow rate, and vascular permeability over two weeks. The results indicated the lack of inflammatory reaction of the host tissue to nc-YSZ at the microscopic level, suggesting that nc-YSZ is a good alternative material for cranial implants.

Three-dimensional Printing and 3D Slicer: Powerful Tools in Understanding and Treating Structural Lung Disease

Recent advances in the three-dimensional (3D) printing industry have enabled clinicians to explore the use of 3D printing in preprocedural planning, biomedical tissue modeling, and direct implantable device manufacturing. Despite the increased adoption of rapid prototyping and additive manufacturing techniques in the health-care field, many physicians lack the technical skill set to use this exciting and useful technology. Additionally, the growth in the 3D printing sector brings an ever-increasing number of 3D printers and printable materials. Therefore, it is important for clinicians to keep abreast of this rapidly developing field in order to benefit. In this Ahead of the Curve, we review the history of 3D printing from its inception to the most recent biomedical applications. Additionally, we will address some of the major barriers to wider adoption of the technology in the medical field. Finally, we will provide an initial guide to 3D modeling and printing by demonstrating how to design a personalized airway prosthesis via 3D Slicer. We hope this information will reduce the barriers to use and increase clinician participation in the 3D printing health-care sector.

Videography supported adhesion, and proliferation behavior of MG-63 osteoblastic cells on 2.5D titania nanotube matrices

Human osteosarcoma cells MG-63 were cultured on anodically etched titania nanotubes (TiO2 NT), with diameters ranging from 40-100 nm, to study the correlations between cell proliferation and adhesion on the 2.5 dimensional (2.5D) extracellular matrix (ECM). Unlike other reports, mostly based on mouse stem cells, and 2D cell culture, our studies indicate that the 2.5D NT promote higher proliferation and activity, but less 2D adhesion. Proliferation of the MG-63 cells was significantly higher in the NTs, the best being the 70 nm diameter sample, compared to planar titania (control). This is consistent with previous studies. However, cellular adhesion was stronger on TiO2 NT with increasing diameter, and highest on the control as obtained from shear stress measurement, paxilin imaging, and western blot measurements probing focal adhesion kinase, p130 CAS, and extracellular-regulated kinase, in addition to cell morphology imaging by fluorescence microscopy. We provide direct videography of cell migration, and cell speed data indicating faster filopodial activity on the TiO2 NT surfaces having lower adhesion. This evidence was not available previously. The NT matrices promote cells with smaller surface area, because of less 2D stretching. In contrast, on comparatively planar 2D-like surfaces uniaxial stretching of the cell body with strong anchoring of the filopodia, resulted in larger cell surface area, and demonstrated stronger adhesion. The difference in the results, with those previously published, may be generally attributed to, among others, the use of mouse stem cells (human osteosarcoma used here), and unannealed as-grown TiO2 NTs used previously (annealed ECMs used here).

Applications of three-dimensional printing technology in the cardiovascular field

Three-dimensional (3-D) printing technology has rapidly developed in the last few decades. Meanwhile, the application of this technology has reached beyond the engineering field and expanded to almost all disciplines, including medicine. There has been much research on the medical applications of 3-D printing in neurosurgery, orthopedics, maxillofacial surgery, plastic surgery, tissue engineering, as well as other fields. Because of the complexity of the cardiovascular system, the application of this technology is limited and difficult, as compared to other disciplines, and thus there is much room for future development. Many of the difficulties associated with this technology must be overcome. Nonetheless, there is no doubt that 3-D printing technology will benefit patients with cardiovascular diseases in the near future.

Management of extensive frontal cranioplasty defects

Cranioplasty is a medical technique to correct cranial bone defects. Depending on the size and location of the defect, a bone substitute can be used to replace the missing bone. Frontal bone defects are important to patients in terms of cosmetics because they are visible. Advances in computer design allow the production of customized implants with improved cosmetic and functional results. This report describes hybrid optimization of three-dimensional technological methods along with traditional methods toward the manufacture of deep-buried titanium implants, restoring frontal skull defects for 4 patients. A three-dimensional model was produced from the computed tomographic scan data of 3 patients using an in-house three-dimensional printer. A new approach was followed in treating the fourth patient. The defect was restored using preoperative scan before cranioplasty. These data were transported digitally into the defect skull to recreate the bone contour required, and a three-dimensional model was produced from the "new" digital model using the three-dimensional printer. Defect areas of the patients were large and measured 101.21 × 123.35 (vertical × horizontal) in average (mm). Conventional wax-up of the defect was carried to restore normal conformity. A titanium sheet (0.5 mm) was swaged into the desired shape; however, convexity of the defect area makes titanium swaging challenging, especially at the deep lateral undercuts. Making side flanges at reasonable lengths made it easy to swage without creasing. Three-dimensional models aided to produce accurately fitting plates. Finally, the sequential method of using both digital and manual procedures is a low-cost, reliable, accurate, and reproducible method.

Surgical planning, three-dimensional model surgery and preshaped implants in treatment of bilateral craniomaxillofacial post-traumatic deformities

PURPOSE

The purpose of the present study was to explore the treatment and outcomes of bilateral craniomaxillofacial post-traumatic deformities with surgical planning, 3-dimensional (3D) model surgery, and preshaped implants.

MATERIALS AND METHODS

We analyzed the preoperative computed tomography (CT) data and designed preliminary surgical plans for 3 patients with bilateral craniomaxillofacial post-traumatic deformities. 3D resin skull models were produced using rapid prototyping technology, and 3D model surgery was performed to determine the location, reduction direction, and shift distance of the osteotomy and to optimize the surgical plans. Titanium plates or mesh were preshaped on the models and then implanted into the patients. The complications, symmetry of the maxillofacial regions, mouth opening, and occlusion were observed 1 month postoperatively.

RESULTS

The patients had good recovery of their facial contour, occlusion, and mouth opening and acceptable symmetry of the bilateral maxillofacial regions. No complications were observed.

CONCLUSIONS

The combination of surgical planning, 3D model surgery, and preshaped implants can provide surgical accuracy and efficiency and good therapeutic outcomes in the treatment of bilateral craniomaxillofacial post-traumatic deformities.

A review of reconstructive materials for use in craniofacial surgery bone fixation materials, bone substitutes, and distractors

Over the last 40 years, craniofacial surgery, in general, and surgery for craniosynostosis, in particular, has witnessed the introduction of a number of new materials for use in operations involving the cranial vault. Some of these materials have proven quite useful over time, while others have failed to meet their stated objectives. In this review, the more popular implant materials are analyzed, and their relative merits and drawbacks are discussed. Craniofacial surgery in the pediatric population has its own unique limitations, quite different from the adult population and those issues are reviewed as well.

Comparison of manually shaped and computer-shaped titanium mesh for repairing large frontotemporoparietal skull defects after traumatic brain injury

Object

The object of this study was to compare the effects and complications of manual and computer-aided shaping of titanium meshes for repairing large frontotemporoparietal skull defects following traumatic brain injury.

Methods

From March 2005 to June 2011, 161 patients with frontotemporoparietal skull defects were observed. Patients were divided into 2 groups according to the repair materials used for cranioplasty: 83 cases used computer-aided shaping for the titanium mesh, whereas the remaining 78 cases used a manually shaped titanium mesh. The advantages and disadvantages of the 2 methods were compared.

Results

No case of titanium mesh loosening occurred in either group. Subcutaneous fluid collection, titanium mesh tilt, and temporal muscle pain were the most common complications. In the manually shaped group, there were 14 cases of effusion, 10 cases of titanium mesh tilt, and 15 cases of temporal muscle pain. In the computer-aided group, there were 6 cases of effusion, 3 cases of titanium mesh tilt, and 6 cases of temporal muscle pain. The differences were significant between the 2 groups (p < 0.05). Other common complications were scalp infection, exposure of titanium mesh, epidural hematoma, and seizures. In the computer-aided group, the operative time decreased (p < 0.01), the number of screws used was reduced (p < 0.01), and the satisfaction of patients was significantly increased (p < 0.05).

Conclusions

Computer-aided shaping of titanium mesh for repairing large frontotemporoparietal skull defects decreases postoperative complications and the operative duration, reduces the number of screws used, increases the satisfaction of patients, and restores the appearance of the patient's head, making it an ideal choice for cranioplasty.

Is polymethylmethacrylate reliable and practical in full-thickness cranial defect reconstructions?

OBJECTIVE

The study aimed to evaluate the success of polymethylmethacrylate cranioplasty combined with various soft tissue coverage techniques in repairing full-thickness cranial defects, to compare our results with similar studies published before, and to describe a simple method of implant premolding.

METHODS

A total of 17 patients who had cranial defects due to various etiologies underwent polymethylmethacrylate cranioplasty. In 10 patients, the implant premolding method was applied. The soft tissue coverage was obtained by primary closure, local flaps, or free flaps.

RESULTS

The follow-up period ranged from 36 hours to 5 years. Only 1 implant became exposed among the 17 patients. One patient died 36 hours after the surgery because of myocardial infarction. The remaining 15 patients had no early or late postoperative complications. Good contour restoration and stable reconstruction of the calvarial defects were realized, and a successful combination of various soft tissue coverage techniques was achieved.

CONCLUSIONS

We concluded that polymethylmethacrylate was a cheap and durable material, useful in full-thickness calvarial defect reconstructions. It can be combined with any soft tissue coverage techniques except skin grafting. In most cases, the simple premolding methods are useful for both defect matching and preventing tissue damage due to exothermic reaction of the material.

Use of rapid prototyping and three-dimensional reconstruction modeling in the management of complex fractures

BACKGROUND

The production of a copy of the fracture or a deformity in a bone with a complex geometry can be one of the important applications of the integration between two modern computer-based technologies, reverse engineering (RE) and rapid prototyping (RP).

METHODS

This article reviews recent development in this field and present a case series about the use of medical CT/MRI scanning, three-dimensional reconstruction, anatomical modeling, computer-aided design, RP and computer-aided implantation in treating a complex fracture of acetabulums, calcaneum, and medial condyle of femur (Hoffa's fracture).

CONCLUSION

The use of RP technology helped us to understand the fracture configuration and to achieve near anatomical reduction. With this we believe, this technology will reduce the surgical time as was observed in our cases. This consequently, will lower the requirement of an anesthetic dosage and decrease the intraoperative blood loss.In summary, the merging of computational analysis, modeling, designing, and fabrication will serve as important means to treat conditions and fractures around joints, spine, acetabulum, and craniofacial region.

LEVEL OF EVIDENCE

Level 4, case series.

Craniofacial reconstruction with bone and biomaterials: review over the last 11 years

This review aims to compare bone grafts and different biomaterials for reconstruction of craniofacial bones in congenital defects, after trauma, and after tumour surgery. A Pubmed search was performed and publications over the last 11 years describing reconstructions of craniofacial bones in non-load-bearing areas were reviewed. Only human studies using bone grafts and biomaterials were included. Studies on skull base reconstruction, distraction osteogenesis, free and pedicled bone flaps and bone-anchored epithesis were excluded. Out of 83 studies, three were prospective, 65 retrospective and 15 studies were case reports. There were seven comparative studies found and some efforts on statistical analysis were made. Except for a few studies, the statistical significant differences in outcomes were found to be related to size and location of bone defects rather than reconstruction method and biomaterial used. An increasing number of alloplastic materials have been available as alternatives to the gold standard autologous bone transplantation for craniofacial bone repair. Comparative studies with statistical analyses on differences in success rates between different biomaterials or bone grafts for specific indications are needed.

Individually Prefabricated Prosthesis for Maxilla Reconstuction

The reconstruction of maxillofacial bone defects by the intraoperative modeling of implants may reduce the predictability of the esthetic result, leading to more invasive surgery and increased surgical time. To improve the maxillofacial surgery outcome, modern manufacturing methods such as rapid prototyping (RP) technology and methods based on reverse engineeing (RE) and medical imaging data are applicable to the manufacture of custom-made maxillary prostheses. After acquisition of data, an individual computer-based 3D model of the bony defect is gernerated. These data are tranferrred into RE software to create the prosthesis using a computer-aided design (CAD) model, which is directed into the RP machine for the production of the physical model. The precise fit of the prosthesis is evaulated using the prosthesis and skull model. The prosthesis is then directly used in investment casting such as "Quick Cast" pattern to produce the titanium model. In the clincical reports presented here, reconstructions of two patients with large maxillary bone defects during the operations, and surgery time was reduced. These cases show that the prefabrication of a prosthesis using modern manufacturing technology is an effective method for maxillofacial defect reconstruction.

Rapid Prototyping

As the appreciation of structural heart disease in children and adults has increased and as catheter-based closure procedures are now being performed in clinical practice, cardiovascular physicians have multiple compelling new reasons to better understand cardiac anatomic and spatial relationships. Current 2-dimensional imaging techniques remain limited both in their ability to represent the complex 3-dimensional relationships present in structural heart disease and in their capacity to adequately facilitate often complex corrective procedures. This review discusses the cardiovascular applications of rapid prototyping, a new technology that may not only play a significant role in the planning of catheter-based interventions but also may serve as a valuable educational tool to enhance the medical community’s understanding of the many forms of structural heart disease.

Mandibular defect reconstruction with the help of mirror imaging coupled with laser stereolithographic modeling technique

With the advent of microsurgery, composite defect in the mandible can be repaired with various forms of osteocutaneous free flaps. However, it is difficult to accurately reconstruct a large defect in the mandible when not enough mandibular reference blueprints remain. This case report describes a large ameloblastoma at the left lower molar region and ascending ramus of the mandible in a 53-year-old male patient. Before surgery, spiral computed tomography scanning of the whole skull of the patient was performed. Using three-dimensional reconstruction and mirror imaging coupled with laser stereolithographic technique, a complete mandibular biomodel with idealized shape was fabricated. A titanium reconstruction plate was made using the biomodel as a guide. The tumor mass together with the left mandible from the second premolar to the condylar head area was resected en bloc. The large mandibular defect was then reconstructed with the precontoured titanium plate and three segments of vascularized fibular bone graft fixed along the plate. The temporomandibular joint was restored with temporal is muscle as an interpositional disc replacement. The complex defect in the mandible was thus repaired with satisfactory functioning and esthetic result. We suggest that with the help of mirror imaging coupled with laser stereolithographic technique, a precontoured titanium plate can be made for the reconstruction of large mandibular defects.

Evaluation of a 3D digital photographic imaging system of the human face

The aim of this study was to investigate the accuracy of a 3D photographic imaging system for potential application in fabrication of maxillofacial prostheses. For validity estimates, computer digitized 3D photographic images of calibrated ruler attached to a model were analysed for linear and curvilinear distances in 1 mm increments (1-50 mm from the centre of the image). Distortion was evaluated from 1 mm distances measured 20, 40 and 60 mm from the centre of the field. To estimate reliability of measurements in vivo, two raters measured the right endocanthion-subnasale distance and the distance between right and left endocathion on images of 10 subjects, repeated three times (30 images total). From the digital file for one subject, a rapid prototyping (RP) machine produced a 3D model of the mid-face. Measures from the model were compared with those of the 3D computer image to estimate error in fabrication. Mean error values for calibrated distances ranged from 0.07 to 0.26 mm for linear distances, 0.08-0.34 mm for curvilinear distances, and 0.06-0.12 mm for distortion from the centre. Intra- and interexaminer correlation ranged from 0.92 to 1.00 and 0.94-1.00 respectively. Measures of the endocanthion and subnasale distances on the RP fabricated mid-face model were within 8% of the corresponding measures on 3D computer images. The accuracy of the photographic 3D imaging system tested was sufficient for clinical description of the mid-face structures and may be potentially useful for rapid prototyping of facial prostheses.