Assessment of cone-beam CT technical image quality indicators and radiation dose for optimal STL model used in visual surgical planning.

OBJECTIVES: The aim of this study was to identify cone-beam computed tomography (CBCT) protocols that offer an optimal balance between effective dose and 3D model for orthognathic virtual surgery planning, using CT as a reference, and to assess whether such protocols can be defined based on technical image quality metrics. METHODS: Eleven CBCT (VISO G7, Planmeca Oy, Helsinki, Finland) scan protocols were selected out of 32 candidate protocols, based on effective dose and technical image quality measurements. Next, an anthropomorphic RANDO SK150 phantom was scanned using these 11 CBCT protocols and 2 CT scanners for bone quantity assessments. The resulting DICOM files were converted into STL models that were used for bone volume and area measurements in the predefined orbital region to assess the validity of each CBCT protocol for VSP. RESULTS: The highest CBCT bone volume and area of the STL models were obtained using normal dose protocol (F2) and ULD protocol (J13) which resulted in 48% and 96% of the mean STL bone volume and 48% and 95% of the bone area measured on CT scanners, respectively. CONCLUSIONS: The optimal normal dose CBCT protocol" F2" offered optimal bone area and volume balance for STL. The optimal CBCT protocol can be defined exhibited similar using CNR and MTF values that were similar with of those of the reference CT scanners'. CBCT scanner with selected protocols can offer a viable alternative to CT scanners for acquiring STL models for VSP at a lower effective dose.

A review on the application of deep learning for CT reconstruction, bone segmentation and surgical planning in oral and maxillofacial surgery.

Computer-assisted surgery (CAS) allows clinicians to personalize treatments and surgical interventions and has therefore become an increasingly popular treatment modality in maxillofacial surgery. The current maxillofacial CAS consists of three main steps: (1) CT image reconstruction, (2) bone segmentation, and (3) surgical planning. However, each of these three steps can introduce errors that can heavily affect the treatment outcome. As a consequence, tedious and time-consuming manual post-processing is often necessary to ensure that each step is performed adequately. One way to overcome this issue is by developing and implementing neural networks (NNs) within the maxillofacial CAS workflow. These learning algorithms can be trained to perform specific tasks without the need for explicitly defined rules. In recent years, an extremely large number of novel NN approaches have been proposed for a wide variety of applications, which makes it a difficult task to keep up with all relevant developments. This study therefore aimed to summarize and review all relevant NN approaches applied for CT image reconstruction, bone segmentation, and surgical planning. After full text screening, 76 publications were identified: 32 focusing on CT image reconstruction, 33 focusing on bone segmentation and 11 focusing on surgical planning. Generally, convolutional NNs were most widely used in the identified studies, although the multilayer perceptron was most commonly applied in surgical planning tasks. Moreover, the drawbacks of current approaches and promising research avenues are discussed.

Pharmacotherapy, drug-drug interactions and potentially inappropriate medication in depressive disorders.

INTRODUCTION: The aim of this study was to describe the number and type of drugs used to treat depressive disorders in inpatient psychiatry and to analyse the determinants of potential drug-drug interactions (pDDI) and potentially inappropriate medication (PIM). METHODS: Our study was part of a larger pharmacovigilance project funded by the German Innovation Funds. It included all inpatients with a main diagnosis in the group of depressive episodes (F32, ICD-10) or recurrent depressive disorders (F33) discharged from eight psychiatric hospitals in Germany between 1 October 2017 and 30 September 2018 or between 1 January and 31 December 2019. RESULTS: The study included 14,418 inpatient cases. The mean number of drugs per day was 3.7 (psychotropic drugs = 1.7; others = 2.0). Thirty-one percent of cases received at least five drugs simultaneously (polypharmacy). Almost one half of all cases received a combination of multiple antidepressant drugs (24.8%, 95% CI 24.1%-25.5%) or a treatment with antidepressant drugs augmented by antipsychotic drugs (21.9%, 95% CI 21.3%-22.6%). The most frequently used antidepressants were selective serotonin reuptake inhibitors, followed by serotonin and norepinephrine reuptake inhibitors and tetracyclic antidepressants. In multivariate analyses, cases with recurrent depressive disorders and cases with severe depression were more likely to receive a combination of multiple antidepressant drugs (Odds ratio recurrent depressive disorder: 1.56, 95% CI 1.41-1.70, severe depression 1.33, 95% CI 1.18-1.48). The risk of any pDDI and PIM in elderly patients increased substantially with each additional drug (Odds Ratio: pDDI 1.32, 95% CI: 1.27-1.38, PIM 1.18, 95% CI: 1.14-1.22) and severity of disease (Odds Ratio per point on CGI-Scale: pDDI 1.29, 95% CI: 1.11-1.46, PIM 1.27, 95% CI: 1.11-1.44), respectively. CONCLUSION: This study identified potential sources and determinants of safety risks in pharmacotherapy of depressive disorders and provided additional data which were previously unavailable. Most inpatients with depressive disorders receive multiple psychotropic and non-psychotropic drugs and pDDI and PIM are relatively frequent. Patients with a high number of different drugs must be intensively monitored in the management of their individual drug-related risk-benefit profiles.

Polypharmacy and the risk of drug-drug interactions and potentially inappropriate medications in hospital psychiatry.

PURPOSE: The aim of this study was to analyze the epidemiology of polypharmacy in hospital psychiatry. Another aim was to investigate predictors of the number of drugs taken and the associated risks of drug-drug interactions and potentially inappropriate medications in the elderly. METHODS: Daily prescription data were obtained from a pharmacovigilance project sponsored by the Innovations Funds of the German Federal Joint Committee. RESULTS: The study included 47 071 inpatient hospital cases from eight different study centers. The mean number of different drugs during the entire stay was 6.1 (psychotropic drugs = 2.7; others = 3.4). The mean number of drugs per day was 3.8 (psychotropic drugs = 1.6; others = 2.2). One third of cases received at least five different drugs per day on average during their hospital stay (polypharmacy). Fifty-one percent of patients received more than one psychotropic drug simultaneously. Hospital cases with polypharmacy were 18 years older (p < 0.001), more likely to be female (52% vs. 40%, p < 0.001) and had more comorbidities (5 vs. 2, p < 0.001) than hospital cases without polypharmacy. The risks of drug-drug interactions (OR = 3.7; 95% CI = 3.5-3.9) and potentially inappropriate medication use in the elderly (OR = 2.2; CI = 1.9-2.5) substantially increased in patients that received polypharmacy. CONCLUSION: Polypharmacy is frequent in clinical care. The number of used drugs is a proven risk factor of adverse drug reactions due to drug-drug interactions and potentially inappropriate medication use in the elderly. The potential interactions and the specific pharmacokinetics and -dynamics of older patients should always be considered when multiple drugs are used.

Predicting the risk of drug-drug interactions in psychiatric hospitals: a retrospective longitudinal pharmacovigilance study.

OBJECTIVES: The aim was to use routine data available at a patient's admission to the hospital to predict polypharmacy and drug-drug interactions (DDI) and to evaluate the prediction performance with regard to its usefulness to support the efficient management of benefits and risks of drug prescriptions. DESIGN: Retrospective, longitudinal study. SETTING: We used data from a large multicentred pharmacovigilance project carried out in eight psychiatric hospitals in Hesse, Germany. PARTICIPANTS: Inpatient episodes consecutively discharged between 1 October 2017 and 30 September 2018 (year 1) or 1 January 2019 and 31 December 2019 (year 2). OUTCOME MEASURES: The proportion of rightly classified hospital episodes. METHODS: We used gradient boosting to predict respective outcomes. We tested the performance of our final models in unseen patients from another calendar year and separated the study sites used for training from the study sites used for performance testing. RESULTS: A total of 53 909 episodes were included in the study. The models' performance, as measured by the area under the receiver operating characteristic, was 'excellent' (0.83) and 'acceptable' (0.72) compared with common benchmarks for the prediction of polypharmacy and DDI, respectively. Both models were substantially better than a naive prediction based solely on basic diagnostic grouping. CONCLUSION: This study has shown that polypharmacy and DDI can be predicted from routine data at patient admission. These predictions could support an efficient management of benefits and risks of hospital prescriptions, for instance by including pharmaceutical supervision early after admission for patients at risk before pharmacological treatment is established.

Mechanical ventilation and the daily cost of ICU care.

BACKGROUND: Intensive care units represent one of the largest clinical cost centers in hospitals. Mechanical ventilation accounts for a significant share of this cost. There is a relative dearth of information quantifying the impact of ventilation on daily ICU cost. We thus determine daily costs of ICU care, incremental cost of mechanical ventilation per ICU day, and further differentiate cost by underlying diseases. METHODS: Total ICU costs, length of ICU stay, and duration of mechanical ventilation of all 10,637 adult patients treated in ICUs at a German hospital in 2013 were analyzed for never-ventilated patients (N = 9181), patients ventilated at least 1 day, (N = 1455) and all patients (N = 10,637). Total ICU costs were regressed on the number of ICU days. Finally, costs were analyzed separately by ICD-10 chapter of main diagnosis. RESULTS: Daily non-ventilated costs were €999 (95%CI €924 - €1074), and ventilated costs were €1590 (95%CI €1524 - €1657), a 59% increase. Costs per non-ventilated ICU day differed substantially and were lowest for endocrine, nutritional or metabolic diseases (€844), and highest for musculoskeletal diseases (€1357). Costs per ventilated ICU day were lowest for diseases of the circulatory system (€1439) and highest for cancer patients (€1594). The relative cost increase due to ventilation was highest for diseases of the respiratory system (94%) and even non-systematic for patients with musculoskeletal diseases (13%, p = 0.634). CONCLUSIONS: Results show substantial variability of ICU costs for different underlying diseases and underline mechanical ventilation as an important driver of ICU costs.

Segmentation of dental cone-beam CT scans affected by metal artifacts using a mixed-scale dense convolutional neural network.

PURPOSE: In order to attain anatomical models, surgical guides and implants for computer-assisted surgery, accurate segmentation of bony structures in cone-beam computed tomography (CBCT) scans is required. However, this image segmentation step is often impeded by metal artifacts. Therefore, this study aimed to develop a mixed-scale dense convolutional neural network (MS-D network) for bone segmentation in CBCT scans affected by metal artifacts. METHOD: Training data were acquired from 20 dental CBCT scans affected by metal artifacts. An experienced medical engineer segmented the bony structures in all CBCT scans using global thresholding and manually removed all remaining noise and metal artifacts. The resulting gold standard segmentations were used to train an MS-D network comprising 100 convolutional layers using far fewer trainable parameters than alternative convolutional neural network (CNN) architectures. The bone segmentation performance of the MS-D network was evaluated using a leave-2-out scheme and compared with a clinical snake evolution algorithm and two state-of-the-art CNN architectures (U-Net and ResNet). All segmented CBCT scans were subsequently converted into standard tessellation language (STL) models and geometrically compared with the gold standard. RESULTS: CBCT scans segmented using the MS-D network, U-Net, ResNet and the snake evolution algorithm demonstrated mean Dice similarity coefficients of 0.87 ± 0.06, 0.87 ± 0.07, 0.86 ± 0.05, and 0.78 ± 0.07, respectively. The STL models acquired using the MS-D network, U-Net, ResNet and the snake evolution algorithm demonstrated mean absolute deviations of 0.44 mm ± 0.13 mm, 0.43 mm ± 0.16 mm, 0.40 mm ± 0.12 mm and 0.57 mm ± 0.22 mm, respectively. In contrast to the MS-D network, the ResNet introduced wave-like artifacts in the STL models, whereas the U-Net incorrectly labeled background voxels as bone around the vertebrae in 4 of the 9 CBCT scans containing vertebrae. CONCLUSION: The MS-D network was able to accurately segment bony structures in CBCT scans affected by metal artifacts.

Wound dehiscences following pre-implant bone augmentation with autogenous iliac crest bone grafts: A retrospective cohort study.

PURPOSE: To evaluate possible risk factors associated with wound dehiscences following pre-implant alveolar bone augmentation with autologous anterior iliac crest bone grafts covered with resorbable collagen membranes or human demineralised bone laminae. MATERIALS AND METHODS: Data of 161 patients who underwent bone augmentation prior to the insertion of dental implants were analysed. The preoperative dental status, locations of alveolar bone augmentation sites and location of wound dehiscences were recorded. Gender, age, smoking, alcohol exposure, and dental and medical histories were reviewed. Information was also collected on the surgeons, augmentation technique, application of a collagen membrane, fixation screw type and suture material. Univariate logistic regression analysis was used to evaluate pre- and perioperative variables as predictors of dehiscences. RESULTS: A total of 42 (26.1%) of the 161 augmented patients developed a wound dehiscence following surgery. Most commonly affected sites were the anterior maxilla, followed by the anterior mandible. Males developed wound dehiscences with higher probability than females (odds ratio female = 0.444; P = 0.025; 95% CI: 0.214 to 0.903). Furthermore, marginal associations (P < 0.10) are found for smoking and an anterior location of the augmentation. Smokers were found to have higher probability of a wound dehiscence (odds ratio 2.089; P = 0.064; 95% CI: 0.957 to 4.500) compared to non-smokers. A posterior location of the augmentation was associated with lower probability of a wound dehiscence (odds ratio 0.188; P = 0.076; 95% CI: 0.035 to 0.802) compared to an anterior location. CONCLUSIONS: Based on this study population, smoking in males seems to be the most important risk factor for the development of wound dehiscences after pre-implant alveolar bone augmentation procedures.

Polymethyl Methacrylate in Patient-Specific Implants: Description of a New Three-Dimension Technique.

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 ±â€Š26.4 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; ±â€Š371.6. None of the implants required removal during the follow-up period.

Effective Radiation Dose in the Wrist Resulting from a Radiographic Device, Two CBCT Devices and One MSCT Device: A Comparative Study.

The objective of the present study was to assess and compare the effective doses in the wrist region resulting from conventional radiography device, multislice computed tomography (MSCT) device and two cone beam computed tomography (CBCT) devices using MOSFET dosemeters and a custom made anthropomorphic RANDO phantom according to the ICRP 103 recommendation. The effective dose for the conventional radiography was 1.0 µSv. The effective doses for the NewTom 5 G CBCT ranged between 0.7 µSv and 1.6 µSv, for the Planmed Verity CBCT 2.4 µSv and for the MSCT 8.6 µSv. When compared with the effective dose for AP- and LAT projections of a conventional radiographic device, this study showed an 8.6-fold effective dose for standard MSCT protocol and between 0.7 and 2.4-fold effective dose for standard CBCT protocols. When compared to the MSCT device, the CBCT devices offer a 3D view of the wrist at significantly lower effective doses.

Using 3D printing techniques to create an anthropomorphic thorax phantom for medical imaging purposes.

PURPOSE: Imaging phantoms are widely used for testing and optimization of imaging devices without the need to expose humans to irradiation. However, commercially available phantoms are commonly manufactured in simple, generic forms and sizes and therefore do not resemble the clinical situation for many patients. METHODS: Using 3D printing techniques, we created a life-size phantom based on a clinical CT scan of the thorax from a patient with lung cancer. It was assembled from bony structures printed in gypsum, lung structures consisting of airways, blood vessels >1 mm, and outer lung surface, three lung tumors printed in nylon, and soft tissues represented by silicone (poured into a 3D-printed mold). RESULTS: Kilovoltage x-ray and CT images of the phantom closely resemble those of the real patient in terms of size, shapes, and structures. Surface comparison using 3D models obtained from the phantom and the 3D models used for printing showed mean differences <1 mm for all structures. Tensile tests of the materials used for the phantom show that the phantom is able to endure radiation doses over 24,000 Gy. CONCLUSIONS: It is feasible to create an anthropomorphic thorax phantom using 3D printing and molding techniques. The phantom closely resembles a real patient in terms of spatial accuracy and is currently being used to evaluate x-ray-based imaging quality and positional verification techniques for radiotherapy.

Work-Time Distribution of Physicians at a German University Hospital.

BACKGROUND: The effective utilization of staff resources is of decisive importance for the adequate, appropriate, and economical delivery of hospital services. The goal of this study was to determine the distribution of working time among doctors in a German university hospital-in particular, in terms of type of activities and time of day. METHODS: The distribution of working time was determined from 14-day samples taken in seven clinical departments of the Medical Center-University of Freiburg. In each 14-day sample, the activities being carried out at multiple, randomly chosen times were recorded. RESULTS: A total of 250 doctors (participation rate: 83%) took part in the study. A total of 20 715 hours of working time was analyzed, representing twelve years of full-time employment. Overall, 46% of working time in the inpatient sector was spent in direct contact with patients, with relevant differences among the participating clinical departments: for instance, the percentage of time taken up by patient contact was 35% in pediatrics and 60% in oral and maxillofacial surgery. Patient contact was highest (over 50% overall) in the period 8 a.m. to 12 noon. CONCLUSION: The amount of working time taken up by activities other than direct patient contact was found to be lower than in previous studies. It remains unclear what distribution of working time is best for patient care and whether it would be possible or desirable to increase the time that doctors spend in direct contact with patients.

MRI and Additive Manufacturing of Nasal Alar Constructs for Patient-specific Reconstruction.

Surgical reconstruction of cartilaginous defects remains a major challenge. In the current study, we aimed to identify an imaging strategy for the development of patient-specific constructs that aid in the reconstruction of nasal deformities. Magnetic Resonance Imaging (MRI) was performed on a human cadaver head to find the optimal MRI sequence for nasal cartilage. This sequence was subsequently used on a volunteer. Images of both were assessed by three independent researchers to determine measurement error and total segmentation time. Three dimensionally (3D) reconstructed alar cartilage was then additively manufactured. Validity was assessed by comparing manually segmented MR images to the gold standard (micro-CT). Manual segmentation allowed delineation of the nasal cartilages. Inter- and intra-observer agreement was acceptable in the cadaver (coefficient of variation 4.6-12.5%), but less in the volunteer (coefficient of variation 0.6-21.9%). Segmentation times did not differ between observers (cadaver P = 0.36; volunteer P = 0.6). The lateral crus of the alar cartilage was consistently identified by all observers, whereas part of the medial crus was consistently missed. This study suggests that MRI is a feasible imaging modality for the development of 3D alar constructs for patient-specific reconstruction.

Finite element analysis of 6 large PMMA skull reconstructions: A multi-criteria evaluation approach.

In this study 6 pre-operative designs for PMMA based reconstructions of cranial defects were evaluated for their mechanical robustness using finite element modeling. Clinical experience and engineering principles were employed to create multiple plan options, which were subsequently computationally analyzed for mechanically relevant parameters under 50N loads: stress, strain and deformation in various components of the assembly. The factors assessed were: defect size, location and shape. The major variable in the cranioplasty assembly design was the arrangement of the fixation plates. An additional study variable introduced was the location of the 50N load within the implant area. It was found that in smaller defects, it was simpler to design a symmetric distribution of plates and under limited variability in load location it was possible to design an optimal for expected loads. However, for very large defects with complex shapes, the variability in the load locations introduces complications to the intuitive design of the optimal assembly. The study shows that it can be beneficial to incorporate multi design computational analyses to decide upon the most optimal plan for a clinical case.

The impact of manual threshold selection in medical additive manufacturing.

PURPOSE: Medical additive manufacturing requires standard tessellation language (STL) models. Such models are commonly derived from computed tomography (CT) images using thresholding. Threshold selection can be performed manually or automatically. The aim of this study was to assess the impact of manual and default threshold selection on the reliability and accuracy of skull STL models using different CT technologies. METHOD: One female and one male human cadaver head were imaged using multi-detector row CT, dual-energy CT, and two cone-beam CT scanners. Four medical engineers manually thresholded the bony structures on all CT images. The lowest and highest selected mean threshold values and the default threshold value were used to generate skull STL models. Geometric variations between all manually thresholded STL models were calculated. Furthermore, in order to calculate the accuracy of the manually and default thresholded STL models, all STL models were superimposed on an optical scan of the dry female and male skulls ("gold standard"). RESULTS: The intra- and inter-observer variability of the manual threshold selection was good (intra-class correlation coefficients >0.9). All engineers selected grey values closer to soft tissue to compensate for bone voids. Geometric variations between the manually thresholded STL models were 0.13 mm (multi-detector row CT), 0.59 mm (dual-energy CT), and 0.55 mm (cone-beam CT). All STL models demonstrated inaccuracies ranging from -0.8 to +1.1 mm (multi-detector row CT), -0.7 to +2.0 mm (dual-energy CT), and -2.3 to +4.8 mm (cone-beam CT). CONCLUSIONS: This study demonstrates that manual threshold selection results in better STL models than default thresholding. The use of dual-energy CT and cone-beam CT technology in its present form does not deliver reliable or accurate STL models for medical additive manufacturing. New approaches are required that are based on pattern recognition and machine learning algorithms.

Altered nasal airflow: an unusual complication following implant surgery in the anterior maxilla.

Dental implants have been in routine clinical use for over three decades and are a predictable treatment modality. However, as with all other aspects of dentistry, complications occur. A 50-year-old female patient with complaints of a long ongoing unpleasant altered nasal airflow presented herself at the VU University Medical Center Amsterdam. Visual inspection of the right nasal cavity revealed that the apical part of a dental implant placed in the upper right first incisor region had perforated the nasal floor and was partially protruding into the nasal cavity. Subsequent treatment consisted of a transnasal resection of the apical part of the dental implant to the level of the nasal floor. After a 12-month follow-up period, the patient reported having no altered nasal airflow. In conclusion, dental implants protruding into the nasal cavity can cause an alteration to the airflow. Furthermore, a partial removal of the apical part of the dental implant is a viable method of treating dental implants that extend into the nasal cavity.

Airway Management of a Patient with an Acute Floor of the Mouth Hematoma after Dental Implant Surgery in the Lower Jaw.

BACKGROUND: Over the last decades, dental implants have become increasingly popular in the prosthetic rehabilitation of patients. This has subsequently led to an increase of perioperative complications. Obstruction of the airway as a result of a floor of mouth hematoma after dental implant surgery is a rare but life-threatening complication. CASE REPORT: A 62-year-old man presented to the emergency department with a compromised airway caused by a hematoma in the floor of the mouth that occurred during dental implant surgery in the edentulous anterior mandible. Computed tomography angiography images revealed an elevation of the floor of mouth with subsequent occlusion of the airway. In addition, a perforation of the lingual mandibular cortical plate was observed that was caused by two malpositioned dental implants. Awake fiberoptic intubation was immediately performed, the two malpositioned dental implants were subsequently removed, and the patient was extubated after 3 days. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: Perforation of the lingual mandibular cortical plate during dental implant surgery can lead to life-threatening bleeding in the floor of the mouth. This condition can be successfully treated by awake fiberoptic intubation and, if necessary, the malpositioned dental implants can be subsequently removed.

Tooth autotransplantation in the anterior maxilla and mandible: retrospective results in young patients.

OBJECTIVE: This retrospective study evaluated survival rates, prognosis, and overall success of autotransplanted teeth in young patients missing anterior teeth as a result of trauma, agenesis, or developmental disturbances. STUDY DESIGN: Retrospective data were collected from the medical records of patients who had undergone tooth autotransplantations to anterior sites between January 2001 and December 2012. Clinical variables, such as gender, age, surgical indications, donor and recipient sites, type of anesthetics, bone augmentation, and complications during follow-up, were assessed. RESULTS: A total of 59 donor teeth in 46 patients (30 boys and 16 girls; average age 12.15 years) were autotransplanted to the anterior region of the maxilla and mandible. After a mean follow-up period of 17.35 months (range 10-61 months), all of the transplanted teeth remained in situ with no complications. CONCLUSIONS: This study supports the autotransplantation of teeth to the anterior alveolus as a viable option suitable in growing patients with missing anterior teeth.

A Novel Method of Orbital Floor Reconstruction Using Virtual Planning, 3-Dimensional Printing, and Autologous Bone.

Fractures of the orbital floor are often a result of traffic accidents or interpersonal violence. To date, numerous materials and methods have been used to reconstruct the orbital floor. However, simple and cost-effective 3-dimensional (3D) printing technologies for the treatment of orbital floor fractures are still sought. This study describes a simple, precise, cost-effective method of treating orbital fractures using 3D printing technologies in combination with autologous bone. Enophthalmos and diplopia developed in a 64-year-old female patient with an orbital floor fracture. A virtual 3D model of the fracture site was generated from computed tomography images of the patient. The fracture was virtually closed using spline interpolation. Furthermore, a virtual individualized mold of the defect site was created, which was manufactured using an inkjet printer. The tangible mold was subsequently used during surgery to sculpture an individualized autologous orbital floor implant. Virtual reconstruction of the orbital floor and the resulting mold enhanced the overall accuracy and efficiency of the surgical procedure. The sculptured autologous orbital floor implant showed an excellent fit in vivo. The combination of virtual planning and 3D printing offers an accurate and cost-effective treatment method for orbital floor fractures.

Advances in Bioprinting Technologies for Craniofacial Reconstruction.

Recent developments in craniofacial reconstruction have shown important advances in both the materials and methods used. While autogenous tissue is still considered to be the gold standard for these reconstructions, the harvesting procedure remains tedious and in many cases causes significant donor site morbidity. These limitations have subsequently led to the development of less invasive techniques such as 3D bioprinting that could offer possibilities to manufacture patient-tailored bioactive tissue constructs for craniofacial reconstruction. Here, we discuss the current technological and (pre)clinical advances of 3D bioprinting for use in craniofacial reconstruction and highlight the challenges that need to be addressed in the coming years.