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Objectives: In this cadaveric study, the accuracy of CAS guided mandibular and maxillary reconstruction including immediate dental implant placement in different Brown defect classes is assessed. Materials and methods: The virtual planning and surgical procedure was conducted according to a newly proposed Amsterdam UMC reconstruction protocol. Postoperative evaluation was performed according to a previously proposed evaluation guideline. Results: Fourteen mandibular and 6 maxillary reconstructions were performed. Average mandibular angle deviations were 1.52°±1.32, 1.85°±1.58, 1.37°±1.09, 1.78°±1.37, 2.43°±1.52 and 2.83°±2.37, respectively for the left and right axial angles, left and right coronal angles and left and right sagittal angles. A total of 62 dental implants were placed in neomandibles with an average dXYZ values of 3.68 ± 2.21 mm and 16 in neomaxillas with an average dXYZ values of 3.24 ± 1.7 mm. Conclusion: Promising levels of accuracy were achieved for all mandibular angles. Dental implant positions approached the preoperative preferred positions well, within the margin to manufacture prosthetic devices.

Post–kala-azar dermal leishmaniasis may occur after successful treatment of visceral leishmaniasis and is characterized by macules, papules, or nodules in the skin, with varying size. The response to antileishmanial therapy remains difficult to assess because there are presently no reliable biomarkers. To date, skin lesions are clinically assessed for decrease in size or change in color, which is invariably subjective. Novel 3-dimensional optical scanning devices offer safe and field-adapted methods to objectively assess skin lesions for changes over time in size and color that can be quantified with great accuracy.

BackgroundOsteoradionecrosis (ORN) of the mandible is a severe complication of radiation therapy in head and neck cancer patients. Treatment of advanced stage mandibular osteoradionecrosis may consist of segmental resection and osseous reconstruction, often sacrificing the inferior alveolar nerve (IAN). New computer-assisted surgery (CAS) techniques can be used for guided IAN preservation and 3D radiotherapy isodose curve visualization for patient specific mandibular resection margins. This study introduces a novel treatment concept combining these CAS techniques for treatment of advanced stage ORN.MethodsOur advanced stage ORN treatment concept includes consecutively: 1) determination of the mandibular resection margins using a 3D 50 Gy isodose curve visualization, 2) segmental mandibular resection with preservation of the IAN with a two-step cutting guide, and 3) 3D planned mandibular reconstruction using a hand-bent patient specific reconstruction plate. Postoperative accuracy of the mandibular reconstruction was evaluated using a guideline. Objective and subjective IAN sensory function was tested for a period of 12 months postoperatively.ResultsFive patients with advanced stage ORN were treated with our ORN treatment concept using the fibula free flap. A total of seven IANs were salvaged in two men and three women. No complications occurred and all reconstructions healed properly. Neither non-union nor recurrence of ORN was observed. Sensory function of all IANs recovered after resection up to 100 percent, including the patients with a pathologic fracture due to ORN. The accuracy evaluation showed angle deviations limited to 3.78 degrees. Two deviations of 6.42° and 7.47° were found. After an average of 11,6 months all patients received dental implants to complete oral rehabilitation.ConclusionsOur novel ORN treatment concept shows promising results for implementation of 3D radiotherapy isodose curve visualization and IAN preservation. Sensory function of all IANs recovered after segmental mandibular resection.

Valid comparisons of postoperative accuracy results in computer-assisted reconstruction of the mandible are difficult due to heterogeneity in imaging modalities, mandibular defect classification, and evaluation methodologies between studies. This guideline uses a step-by-step approach guiding the process of imaging, classification of mandibular defects and volume assessment of three-dimensional (3D) models, after which a legitimized quantitative accuracy evaluation method can be performed between the postoperative clinical situation and the preoperative virtual plan. The condyles and the vertical and horizontal corners of the mandible are used as bony landmarks to define virtual lines in the computer-assisted surgery (CAS) software. Between these lines the axial, coronal, and both sagittal mandibular angles are calculated on both pre-and postoperative 3D models of the (neo)mandible and subsequently the deviations are calculated. By superimposing the postoperative 3D model to the preoperative virtually planned 3D model, which is fixed to the XYZ axis, the deviation between pre-and postoperative virtually planned dental implant positions can be calculated. This protocol continues and specifies an earlier publication of this evaluation guideline.

Clinical radiology is increasingly used as a source of data to test or develop forensic anthropological methods, especially in countries where contemporary skeletal collections are not available. Naturally, this requires analysis of the error that is a result of low accuracy of the modality (i.e. accuracy of the segmentation) and the error that arises due to difficulties in landmark recognition in virtual models. The cumulative effect of these errors ultimately determines whether virtual and dry bone measurements can be used interchangeably.To test the interchangeability of virtual and dry bone measurements, 13 male and 14 female intact cadavers from the body donation program of the Amsterdam UMC were CT scanned using a standard patient scanning protocol and processed to obtain the dry os coxae. These were again CT scanned using the same scanning protocol. All CT scans were segmented to create 3D virtual bone models of the os coxae (‘dry’ CT models and ‘clinical’ CT models). An Artec Spider 3D optical scanner was used to produce gold standard ‘optical 3D models’ of ten dry os coxae.The deviation of the surfaces of the 3D virtual bone models compared to the gold standard was used to calculate the accuracy of the CT models, both for the overall os coxae and for selected landmarks. Landmark recognition was studied by comparing the TEM and %TEM of nine traditional inter-landmark distances (ILDs). The percentage difference for the various ILDs between modalities was used to gauge the practical implications of both errors combined.Results showed that ‘dry’ CT models were 0.36–0.45 mm larger than the ‘optical 3D models’ (deviations −0.27 mm to 2.86 mm). ‘Clinical’ CT models were 0.64–0.88 mm larger than the ‘optical 3D models’ (deviations −4.99 mm to 5.00 mm). The accuracies of the ROIs were variable and larger for ‘clinical’ CT models than for ‘dry’ CT models. TEM and %TEM were generally in the acceptable ranges for all ILDs whilst no single modality was obviously more or less reliable than the others. For almost all ILDs, the average percentage difference between modalities was substantially larger than the average percentage difference between observers in ‘dry bone’ measurements only.Our results show that the combined error of segmentation- and landmark recognition error can be substantial, which may preclude the usage of ‘clinical’ CT scans as an alternative source for forensic anthropological reference data.

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.

Smart phones have come out with advanced features that can be useful for medical diagnosis. The Iphone X has a face recognition function to unlock the phone which could actually be used as a full functional 3D scanner. Unfortunately, only a few app developers have seen the potential of the Iphone X. The Bellus3D IOS app is dedicated for face scanning with the option to export data in slt/obj format for analysis on other software platforms. The face scans can be performed in 30 seconds including processing. A hardware adaption was developed to perform 3D scans also in the direction of backside of the Iphone X. To test the resolution and color representation of the Iphone X, scans were obtained of face phantoms and compared with high-end 3D scanners (Artec Spider/EVA and Vectra) using deviation maps. The Iphone X/Bellus3D performed best for the front view of the face. Presence of hair resulted in distortion of the side view. The mesh density was around 0.6-0.8 mm which is less compared to the Artec scanners (

Comparing accuracy results for mandibular reconstructions using computer-assisted surgery (CAS) is limited due to heterogeneity in image acquisition, extent of mandibular resection, and evaluation methodologies between studies. We propose a practical, feasible and reproducible guideline for standardizing evaluation methods to allow valid comparisons of postoperative results and facilitate meta-analyses in the future. It offers a guide to imaging, data comparison, volume assessment of 3-dimensional models, classification of defects, and it also contains a quantitative accuracy evaluation method.

Computer-assisted surgery (CAS) for mandibular reconstruction was developed to improve conventional treatment methods. In the past years, many different software programs have entered the market, offering numerous approaches for preoperative planning and postoperative evaluation of the CAS process of mandibular reconstruction. In this systematic review, we reviewed planning and evaluation methods in studies that quantitatively assessed accuracy of mandibular reconstruction performed with CAS. We included 42 studies describing 413 mandibular reconstructions planned and evaluated using CAS. The commonest software was Proplan/Surgicase CMF (55%). In most cases, the postoperative virtual 3-dimensional model was compared to the preoperative 3-dimensional model, revised to the virtual plan (64%). The commonest landmark for accuracy measurements was the condyle (54%). Accuracy deviations ranged between 0 mm and 12.5 mm and between 0.9° and 17.5°. Because of a lack of uniformity in planning (e.g., image acquisition, mandibular resection size) and evaluation methodologies, the ability to compare postoperative outcomes was limited; meta-analysis was not performed. A practical and simple guideline for standardizing planning and evaluation methods needs to be considered to allow valid comparisons of postoperative results and facilitate meta-analysis in the future.

Currently, allergy testing is performed by exposing the skin to small quantities of potential allergens on the inner forearm thereby scratching the protective epidermis to increase exposure. After 15 minutes the dermatologist performs a visual check of the 'bump' induced by swelling and erythema. In this study, two high resolution 3D scanners (Artec Spider and EVA) were used to quantify the dimensions (circumference, surface area, thickness) of the bump and to assess which parameters correlate with the diagnosis of the dermatologist. For comparison and validation of the scanners and the analysis-software (Artec Studio and GOM Inspect), phantom 'bumps' were developed. In a small clinical feasibility study, data of 3 patients with 17 positive allergic reactions were obtained and analyzed with the optimum settings based on the phantom study. Although both scanners could differentiate between the reaction grade 1, 2 or 3 assigned by the dermatologist, the results were not significant due to the small number of reactions at this time of the study. Both in the phantom and clinical study, the Artec Spider 3D scanner showed the allergic reactions clearly but an practical method of analysis needs to be developed to grade them similar to dermatologists. The resolution of the Artec EVA 3D scanner is lower but this scanner is more practical for use in the clinic (fast and easy to use). 3D scanners have a great potential for quantitative imaging in dermatology and aesthetic surgery.

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.

It is difficult to obtain quantitative measurements as to surface areas and volumes from standard photos of the body parts of patients which is highly desirable for objective follow up of treatments in e.g. dermatology. plastic, aesthetic and reconstructive surgery. Recently, 3-D scanners have become available to provide quantification. Phantoms (3-D printed hand, nose and ear, colored bread sculpture) were developed to compare a range from low-cost (Sense), medium (HP Sprout) to high end (Artec Spider, Vectra M3) scanners using different 3D imaging technologies, as to resolution, working range, surface color representation, user friendliness. The 3D scans files (STL, OBJ) were processed with Artec studio and GOM software as to deviation compared to the high resolution Artec Spider scanner taken as †golden' standard. The HP Spout, which uses a fringe projection, proved to be nearly as good as the Artec, however, needs to be converted for clinical use. Photogrammetry as used by the Vectra M3 scanner is limited to provide sufficient data points for accurate surface mapping however provides good color/structure representation. The low performance of the Sense is not recommended for clinical use. The Artec scanner was successfully used to measure the structure/volume changes in the face after hormone treatment in transgender patients. 3D scanners can greatly improve quantitative measurements of surfaces and volumes as objective follow up in clinical studies performed by various clinical specialisms (dermatology, aesthetic and reconstructive surgery). New scanning technologies, like fringe projection, are promising for development of low-cost, high precision scanners.

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.