3D Surface Scanning Research Articles

Microsurgical Anatomy of the Common Tendinous Ring and Its Surgical Implications

BACKGROUND AND OBJECTIVES: The common tendinous ring (CTR), also known as the common annular tendon or annulus of Zinn, is a critical anatomic structure located at the convergence of the orbital apex, superior orbital fissure (SOF), optic canal, and the anterior aspect of the lateral sellar compartment. It plays a vital role in both neurosurgical and neuro-ophthalmological interventions. The aim of this study was to delineate the complex 3-dimensional (3D) topography of the CTR and explore its implications for surgical procedures. METHODS: Ten formalin-fixed skull base specimens from adult Chinese cadavers were meticulously dissected to investigate the morphology of the CTR, focusing particularly on its relationship with the 4 extraocular rectus tendons, the optic strut, the SOF, and the optic canal. Additional skull base specimens were subjected to 3D surface scanning, computed tomography, and histopathological examinations to deepen our understanding of the CTR's structural complexities. RESULTS: The CTR establishes a spatial, 3D tendinous assembly, encompassing 4 rectus tendons, 2 tendinous connections, and a singular common tendinous root. These components interlink to form a distinctive dual-ring configuration, featuring the optic foramen and the oculomotor foramen. The posterior part of the superior rectus tendon demarcates the common boundary between these 2 foramina. The oculomotor foramen itself serves as the central sector of the SOF. Precise incisions of the medial and lateral tendinous connections and fusions are essential for safely opening the CTR. CONCLUSION: The structural composition, interconnections, and dual-ring configuration of the CTR are crucial for precise and safe surgery of orbital apex and adjacent regions.

Field investigation of the feasibility of MICP for Mitigating Natural Rainfall-Induced erosion in gravelly clay slope

Rainfall-induced erosion on slopes is a prevalent natural process leading to soil loss. One promising application of microbially induced carbonate precipitation (MICP) is to mitigate rainfall-induced erosion. Conducting field tests is an essential step to verify and improve its performance. In the current work, field tests were conducted to assess the feasibility of using MICP to mitigate rainfall-induced erosion on a gravelly clay slope in Longyan, Fujian, China. A temporary laboratory was set up to cultivate bacteria, and a non-sterilizing method was employed to prepare large volumes of bacterial suspensions in a single batch. Slopes were treated by spraying solutions onto their surfaces. The amount of discharged soils and 3D surface scanning results were used for evaluating the erosion intensity of the slopes. The results demonstrated that the method could effectively mitigate the surface erosion caused by natural rainfall and prevent erosion-induced collapse. Notably, approximately one year after the treatment, the grass had started to grow on the heavily cemented slope, indicating that the MICP method is both effective and eco-friendly for soil stabilization method. However, further improvements are needed to enhance the uniformity and long-term durability of the MICP treatment.

The Ediacara Biota of the Wood Canyon formation: Latest Precambrian macrofossils and sedimentary structures from the southern Great Basin

Fossils of the Ediacara Biota preserve the oldest indisputable evidence of macroscopic animal life. Although new finds continue to expand the near global distribution of such organisms, relatively abundant and diverse populations of these primarily soft-bodied taxa are known from just a handful of localities. More commonly, reports of late Precambrian fossils consist of comparably lower diversity assemblages (less than ∼10 genera), with a limited number of total specimens (less than ∼1000 reported macrofossils over a broad geographic area). Determining the factors responsible for such differences can help to fully appreciate preserved patterns of Ediacaran biodiversity.The lower member of the Wood Canyon Formation in the Death Valley region of the southern Great Basin, USA contains fossils of the Ediacara Biota. Here we redescribe previously recovered specimens based on new data from 3D surface scans and report several new finds from this unit. Although this allows the addition of two Ediacara taxa (Pteridinium and Charnia?) to the known diversity in the region, most potential macrofauna consist of amorphous, irregular forms with minimal preserved structures wherein an abiotic origin cannot be ruled out. A combination of factors – including variable taphonomic conditions, difficulty of identification and an original depauperate community – contribute to the observed diversity of this assemblage. Many biases that impact this record are either common (e.g., age, preservation requirements, difficulty of recognition) or comparable (e.g., paleoenvironmental and taphonomic controls) to known occurrences of Ediacara macrofauana. Thus, we argue this fossil record at least partially reflects the original community composition, suggesting that fossils of the lower Wood Canyon record a signal of relatively low diversity of the Ediacara Biota in the lead up to the Ediacaran-Cambrian boundary.

Measuring avian bill size: comparing and evaluating 3D surface scanning with traditional size estimates in Australian birds

Unidimensional measurements for estimating bill size, like length and width, are commonly used in ecology and evolution, but can be criticised due to issues with repeatability and accuracy. Furthermore, formula‐based estimates of bill surface area tend to assume uniform bill shapes across species, which is rarely the case. 3D surface scanning can potentially help overcome some such issues by collecting detailed external morphology and direct measurements of surface area, rather than composite estimates of size. Here, we evaluate the use of 3D surface scanners on avian museum specimens to test the repeatability of 3D‐based measurements and compare these to traditional formula‐based methods of estimating bill size from unidimensional measurements. Using 28 Australian bird species, we investigate inter‐observer repeatability of surface area measurements from 3D surface scans. We then compare 3D‐based size estimates to formula‐based size estimates to infer the accuracy and precision of formula‐based measurements of bill surface area. We find that morphometric measurements from 3D surface scans are highly repeatable between observers, without the need for extensive training, demonstrating an advantage over unidimensional measuring methods, like callipers. When comparing 3D‐based measurements to formula‐based estimates of bill surface area, most formulae for estimating size consistently underestimate surface area, and with considerable variation between species. Where 3D scanning is not possible, we find that a commonly used cone formula for estimating bill size is most precise across diverse bill shapes, therefore supporting its use in interspecific contexts. However, we find that incorporating an additional unidimensional measure of bill curvature into formulae improves the accuracy of the calculated area. Our results reveal the high potential for 3D surface scanners in avian morphometric research, especially for studies necessitating large sample sizes collected by multiple observers, and gives suggestions for formula‐based approaches to estimate bill size.

Multimethod Analysis of a Novel Multi-coloured Heat-treated Nickel-Titanium Rotary System: Design, Metallurgy, Mechanical Properties, and Shaping Ability

IntroductionThis study aimed to compare a new multicolored rotary system with four heat-treated rotary instruments using the multimethod approach. MethodsThree-hundred instruments of RCS Rainbow, Rotate, RaCe EVO, OneCurve, and ProTaper Ultimate systems were evaluated regarding their design (stereomicroscopy, scanning electron microscopy, and 3D surface scanning), metallurgy, and mechanical performance (cyclic fatigue, torsional resistance, bending and buckling resistance, and cutting ability). Unprepared surfaces after canal preparation of maxillary molars were evaluated using micro-computed tomography. Kruskal-Wallis and one-way analysis of variance post hoc Tukey tests were used for statistical comparisons (α = 5%). ResultsInstruments exhibited variations in active blade length, number of spirals, and cross-sectional designs. RCS Rainbow showed specific phase transformation temperatures, highest bending (400.5gf) and buckling (286gf) resistance values, and lowest mean angle of rotation (529°) (P < .05). OneCurve exhibited superior cutting ability (8.4 mm) and longer time to fracture (112s). RaCe EVO displayed the lowest time to fracture (51s), maximum torque (1.2 N.cm), buckling (174gf), and bending resistance (261gf) values (P < .05). ProTaper Ultimate showed the highest torque (1.6 N.cm) and angle of rotation (611°) (P < .05), while its bending load (262gf) was comparable to RaCe EVO (P > .05). Rotate instrument showed intermediate values in the mechanical tests. No difference was observed regarding the unprepared canal surfaces (P > .05) ConclusionsRCS Rainbow demonstrates a trade-off between flexibility and other mechanical properties. Its dimensions exceeded those of other instruments, affording it higher torque resistance, yet concurrently reducing its flexibility, angle of rotation, and cutting ability. OneCurve stands out as a well-balanced choice by integrating geometric design and mechanical performance.

Hybrid Inspection Method using Three Dimensional Scanning, Lock-in Thermography and Laser Shearography

The proportion of composite materials (such as CFRP) to the metal used on the modern aircrafts is rising, imposing different kind of failure modes. Since the composite structures are known to be sensitive to the impact loading, there is need for means to assess the sub-surface damage in the structure rapidly. Royal Netherlands Aerospace Centre NLR has an extensive track record on contactless non-destructive inspection (NDI) methods based on optical sensors, such as 3D surface scanning, lock-in thermography and laser shearography. The combination of these methods (multi-domain inspection) enables us to assess the structural integrity of an aircraft outer surface in a short time, reducing inspection costs and the “down time” of the aircraft. Recently, NLR is working towards a 3D oriented mesh environment of an object, enhanced with NDI data, providing sub-surface damage information. By automatically stitching the 3D object images, it is possible to expand this method for a complete scan of an aircraft surface. Furthermore, the thermographic and shearography imaging information has been integrated into the 3D surface accounting for the image distortion from the different measurement angles. In this paper, the results from the various studies will be presented involving integration of the 2D measurements with the 3D scan mesh. Keywords: Thermography, Shearography, 3D scanning, Data fusion

Long-term results of minimally invasive strip craniectomy without helmet therapy for scaphocephaly - a single-centre experience.

Scaphocephaly is the most common type of craniosynostosis and various surgical techniques are used for treatment. Due to late postoperative changes of the head shape, long-term outcome data is important for evaluating any new surgical technique. At our institution, minimally invasive strip craniectomy without regular helmet therapy is the standard treatment in scaphocephalic patients. Between October 2021 and February 2023, we retrospectively examined the skull shape of patients who underwent minimally invasive strip craniectomy for scaphocephaly using a 3D surface scan technique. The cephalic index (CI), the need for helmet therapy and additional cosmetic outcome parameters were investigated. We included 70 patients (72.5% male). The mean follow-up time was 46 (10-125) months and the mean CI was 75.7 (66.7-85.2). In 58 patients, the final cosmetic result was rated as "excellent/good" (mean CI: 76.3; 70.4-85.0), in 11 as "intermediate" (mean CI: 73.3; 66.7-77.6), and in one case as "unsatisfactory" (CI 69.3). The presence of a suboccipital protrusion was associated with a "less than good" outcome. The CI correlated significantly with the overall outcome, the presence of frontal bossing, and the interval between scan and surgery (age at scan). Minimally invasive strip craniectomy is an elegant and safe method to correct scaphocephaly. Our data show good cosmetic results in the long term even without regular postoperative helmet therapy.

Three-dimensional imaging of the forearm and hand: A comparison between two 3D imaging systems.

The conventional treatment for distal radius fractures typically involves immobilization of the injured extremity using a conventional forearm cast. These casts do cause all sorts of discomfort during wear and impose life-style restrictions on the wearer. Personalized 3D printed splints, designed using three-dimensional (3D) imaging systems, might overcome these problems. To obtain a patient specific splint, commercially available 3D camera systems are utilized to capture patient extremities, generating 3D models for splint design. This study investigates the feasibility of utilizing a new camera system (SPENTYS) to capture 3D surface scans of the forearm for the design of 3D printed splints. In a prospective observational cohort study involving 17 healthy participants, we conducted repeated 3D imaging using both the new (SPENTYS) and a reference system (3dMD) to assess intersystem accuracy and repeatability. The intersystem accuracy of the SPENTYS system was determined by comparison of the 3D surface scans with the reference system (3dMD). Comparison of consecutive images acquired per device determined the repeatability. Feasibility was measured with system usability score questionnaires distributed among professionals. The mean absolute difference between the two systems was 0.44 mm (SD:0.25). The mean absolute difference of the repeatability of the reference -and the SPENTYS system was respectively 0.40 mm (SD: 0.30) and 0.53 mm (SD: 0.25). Both repeatability and intersystem differences were within the self-reported 1 mm. The workflow was considered easy and effective, emphasizing the potential of this approach within a workflow to obtain patient specific splint.

A fast simulation method for thermal management in wire arc additive manufacturing repair of a thin-walled structure

Ensuring first-time-right on-site repair of critical structures is a key challenge for additive manufacturing (AM)–based repair solutions. Fast thermal simulations are thus needed to plan efficient and error-free AM processes. This paper addresses a fast thermal simulation method for a novel subsea wire arc additive manufacturing (SWAAM) repair procedure. Current commercial finite element (FE) codes for typical welding and AM are computationally expensive and slow. The presented 2D finite difference approach can be used to simulate SWAAM on a damaged plate with around 70 times acceleration compared to real welding times, without the use of parallelization. Although not being able to accurately represent the temperature in close vicinity of the welding torch, the approach shows excellent correspondence with FE simulations and experiments in regions of the plate where the temperature has assumed a distribution that is largely two-dimensional. Compared with FE simulations, the approach is experimentally verified to be accurate to 10 °C within 7 s after the welding torch has passed a point on the plate. Thus, the approach can provide a measure of the global temperature field in a thin-walled structure during repair. The thermal simulation is preceded by a welding path planner, which generates appropriate paths based on slicing of a 3D surface scan of the damage that is to be repaired. Damages to equipment or non-ideal welding conditions are prevented by automatically pausing the welding if the calculated temperature in the path ahead of the welding torch exceeds a predefined interpass temperature limit.

3D Surface Scanning for Virtual CT-Based Electron Beam Treatment Planning in Skin Malignancies of the Head and Neck

3D Surface Scanning for Virtual CT-Based Electron Beam Treatment Planning in Skin Malignancies of the Head and Neck

Multimethod analysis of large- and low-tapered single file reciprocating instruments: Design, metallurgy, mechanical performance, and irrigation flow.

To compare eight large- and low-tapered heat-treated reciprocating instruments regarding their design, metallurgy, mechanical properties, and irrigation flow through an in silico model. A total of 472 new 25-mm E-Flex Rex (25/.04 and 25/.06), Excalibur (25/.05), Procodile (25/.06), Reciproc Blue R25 (25/.08v), WaveOne Gold Primary (25/.07v), and Univy Sense (25/.04 and 25/.06) instruments were evaluated regarding their design (stereomicroscopy, scanning electron microscopy, and 3D surface scanning), metallurgy (energy-dispersive X-ray spectroscopy and differential scanning calorimetry), and mechanical performance (cyclic fatigue, torsional resistance, cutting ability, bending and buckling resistance). Computational fluid dynamics assessment was also conducted to determine the irrigation flow pattern, apical pressure, and wall shear stress in simulated canal preparations. Kruskal-Wallis and one-way anova post hoc Tukey tests were used for statistical comparisons (α = 5%). Instruments presented variations in blade numbers, helical angles, and tip designs, with all featuring non-active tips, symmetrical blades, and equiatomic nickel-titanium ratios. Cross-sectional designs exhibited an S-shaped geometry, except for WaveOne Gold. Univy 25/.04 and Reciproc Blue displayed the smallest and largest core diameters at D3. Univy 25/.04 and E-Flex Rec 25/.04 demonstrated the longest time to fracture (p < .05). Reciproc Blue and Univy 25/.04 exhibited the highest and lowest torque to fracture, respectively (p < .05). Univy 25/.04 and Reciproc Blue had the highest rotation angles, whilst E-Flex Rec 25/.06 showed the lowest angle (p < .05). The better cutting ability was observed with E-Flex Rec 25/.06, Procodile, Excalibur, and Reciproc Blue (p > .05). Reciproc R25 and E-Flex Rec showed the highest buckling resistance values (p < .05), with WaveOne Gold being the least flexible instrument. The impact of instruments' size and taper on wall shear stress and apical pressure did not follow a distinct pattern, although Univy 25/.04 and E-Flex Rec 25/.06 yielded the highest and lowest values for both parameters, respectively. Low-tapered reciprocating instruments exhibit increased flexibility, higher time to fracture, and greater angles of rotation, coupled with reduced maximum bending loads and buckling strength compared to large-tapered instruments. Nevertheless, low-tapered systems also exhibit lower maximum torque to fracture and inferior cutting ability, contributing to a narrower apical canal enlargement that may compromise the penetration of irrigants in that region.

Generative deep learning furthers the understanding of local distributions of fat and muscle on body shape and health using 3D surface scans

BackgroundBody shape, an intuitive health indicator, is deterministically driven by body composition. We developed and validated a deep learning model that generates accurate dual-energy X-ray absorptiometry (DXA) scans from three-dimensional optical body scans (3DO), enabling compositional analysis of the whole body and specified subregions. Previous works on generative medical imaging models lack quantitative validation and only report quality metrics.MethodsOur model was self-supervised pretrained on two large clinical DXA datasets and fine-tuned using the Shape Up! Adults study dataset. Model-predicted scans from a holdout test set were evaluated using clinical commercial DXA software for compositional accuracy.ResultsPredicted DXA scans achieve R2 of 0.73, 0.89, and 0.99 and RMSEs of 5.32, 6.56, and 4.15 kg for total fat mass (FM), fat-free mass (FFM), and total mass, respectively. Custom subregion analysis results in R2s of 0.70–0.89 for left and right thigh composition. We demonstrate the ability of models to produce quantitatively accurate visualizations of soft tissue and bone, confirming a strong relationship between body shape and composition.ConclusionsThis work highlights the potential of generative models in medical imaging and reinforces the importance of quantitative validation for assessing their clinical utility.

Novel Technique of Interproximal Enamel Reduction Based on Computer-Aided Navigation Technique-An In Vitro Study.

The aim of this study was to analyze and compare the accuracy of a novel interproximal enamel reduction (IPR) technique based on a computer-aided static navigation technique with respect to a conventional free-hand-based technique for interproximal enamel reduction. Twenty anatomical-based experimental cast models of polyurethane were randomly distributed into the following IPR techniques: IPR technique based on computer-aided static navigation technique (n = 10) (GI) for Group A and conventional free-hand-based technique for the IPR (n = 10) (FHT) for Group B. The anatomical-based experimental cast models of polyurethane randomly assigned to the GI study group were submitted for a preoperative 3D intraoral surface scan; then, datasets were uploaded into 3D implant-planning software to design virtual templates for the interproximal enamel reduction technique. Afterward, the anatomical-based experimental cast models of polyurethane of both GI and FHT study groups were subjected to a postoperative digital impression by a 3D intraoral surface scan to compare the accuracy of the interproximal enamel reduction techniques at the buccal (mm), lingual/palatal (mm), and angular (◦) levels using the Student t-test. Statistically significant differences between the interproximal enamel reduction technique based on the computer-aided static navigation technique and the conventional free-hand-based technique for the interproximal enamel reduction at the buccal (p = 0.0008) and lingual/palatal (p < 0.0001) levels; however, no statistically significant differences were shown at the angular level (p = 0.1042). The interproximal enamel reduction technique based on computer-aided static navigation technique was more accurate than the conventional free-hand-based technique for interproximal enamel reduction.

Performance of an adjustable compression wrap in occupational leg swelling.

Edema in some subjects worsens over time and wraps help to reduce the leg volume. An adjustable compression wrap was tried on volunteers for 5 h and volumes measured in each limb before and after wrapping using a 3D surface scanner (HandySCAN 3D®) to estimate the volume of the leg. The contralateral leg was used as control. We observed a significant decrease in volume in the wrap legs and an increase in the control legs (p < .001), both in the lower part of leg (p = .001) and in the upper part (p = .001). Using the Readywrap® for 5hours significantly reduces the leg volume. This study enables Readywrap to be studied in a population that is easy to observe in the context of a research program. The Handyscan3D® was shown accurate and reproducible to assess leg volume in future studies.

Accurate specimen digitization through glass achieved and validated using 3D surface scanning

Accurate specimen digitization through glass achieved and validated using 3D surface scanning

Determination of stress concentration factors of welded joints from 3D-surface scans by artificial neural networks

The surface geometry and the stress concentration of welded joints show a large variation and are individual for each joint at each position. This is one reason for the conservative fatigue assessment of welded joints. In the past the determination of stress concentration factors (SCF) by Finite Element (FE) simulations was based on the approximated surface geometry of the weld, defined by weld toe radius and flank angle or other geometrical parameters. In this work a new approach is presented to directly determine SCFs of welded joints based on the 2D-profile (coordinates) of the weld surfaces. For this, two convolutional neural networks (CNN) PointNet++ and 2DLaserNet for point cloud classification are modified to perform regression on 2D-profiles. As input parameter artificial 2D-profiles were generated. The artificial neural networks (ANN) were trained by using the SCFs determined by Finite Element (FE)-simulations based on the virtual 2D-profiles. Both ANN show a high performance (R2 score) for the determination of SCFs. Comparison of the proposed method with three analytical solutions shows in two cases a higher agreement and in one case a similar agreement.

Biomechanical comparative finite element analysis between a conventional proximal interphalangeal joint flexible hinge implant and a novel implant design using a rolling contact joint mechanism

BackgroundThe rolling contact joint (RCJ) mechanism is a system of constraint that allows two circular bodies connected with flexible straps to roll relative to one another without slipping. This study aims to compare the biomechanical characteristics between the conventional proximal interphalangeal joint (PIPJ) flexible hinge (FH) implant and the novel PIPJ implant adopting a RCJ mechanism during PIPJ range of motion using finite element (FE) analysis.MethodsThe three-dimensional (3D) surface shape of a conventional PIPJ FH implant was obtained using a 3D laser surface scanning system. The configuration and parameters of the novel PIPJ implant were adapted from a previous study. The two implants were assumed to have the same material characteristics and each implant was composed of a hyperelastic material, silicone elastomers. The configuration data for both implants were imported to a computer-aided design program to generate 3D geometrical surface and hyperelastic models of both implants. The hyperelastic models of both implants were imported into a structural engineering software to produce the FE mesh and to perform FE analysis. The FE analysis modeled the changes of mechanics during flexion–extension motion between 0° and 90° of two PIPJ implants. The mean and maximum values of von-Mises stress and strain as well as the total moment reaction based on the range of motion of the PIPJs were calculated. The mean values within the PIPJ’s functional range of motion of the mean and maxinum von-Mises stress and strain and the total moment reaction were also determined.ResultsThe maximum values for the von-Mises stress, and strain, as well as the total moment reactions of the conventional PIPJ FH and novel PIPJ implants were all at 90° of PIPJ flexion. The maximum value of each biomechanical property for the novel PIPJ implant was considerably lower compared with that of the conventional PIPJ FH implant. The mean values within the PIPJ’s functional range of motion of the maximum von-Mises stress and strain for the novel PIPJ implant was approximately 6.43- and 6.46-fold lower compared with that of the conventional PIPJ FH implant, respectively. The mean value within a PIPJ’s functional range of motion of the total moment reaction of the novel PIPJ implant was approximately 49.6-fold lower compared with that of the conventional PIPJ FH implant.ConclusionsThe novel PIPJ implant with an RCJ mechanism may offer improved biomechanical performance compared with conventional PIPJ FH implant.

Study on the Difference of Fracture Extension in Hydraulic Fracturing of Marine and Continental Shales Based on Optical Scanning Technology

After hydraulic fracturing, the geometric characteristics of rock morphology is a crucial means for evaluating the effectiveness of fracture stimulation in enhancing production. In order to quantitatively analyze the surface undulations of marine and continental shale morphology further following hydraulic fracturing, a method for calculating the three-dimensional fractal dimension of fracture surfaces based on optical scanning technology is proposed. This method involves the acquisition of point cloud data using a 3D surface scanner. The obtained data are subsequently subjected to smoothing processes, followed by the reconstruction of the three-dimensional representation of the fractures. The box-counting dimension algorithm is employed to calculate the fractal characteristics of post-fracture morphology. The research results indicate that marine shale, due to its higher proportion of brittle minerals such as quartz and calcite, predominantly exhibits vertically oriented longitudinal fractures, perpendicular to the minimum horizontal stress. The average initiation pressure is 8% higher compared to continental shale, with an average fractal dimension of 2.24397. In contrast, continental shale, characterized by its high clay content and the development of natural fractures and bedding planes, is more prone to capturing hydraulic fracture features, resulting in predominantly single transverse shear fractures. The average fractal dimension is 2.087065, which is 7% lower than that of marine shale. These research findings offer a certain degree of guidance for the optimization of fracturing process parameters for different types of reservoirs.

Towards a radiation free numerical modelling framework to predict spring assisted correction of scaphocephaly

Sagittal Craniosynostosis (SC) is a congenital craniofacial malformation, involving premature sagittal suture ossification; spring-assisted cranioplasty (SAC) – insertion of metallic distractors for skull reshaping – is an established method for treating SC. Surgical outcomes are predictable using numerical modelling, however published methods rely on computed tomography (CT) scans availability, which are not routinely performed. We investigated a simplified method, based on radiation-free 3D stereophotogrammetry scans. Eight SAC patients (age 5.1 ± 0.4 months) with preoperative CT and 3D stereophotogrammetry scans were included. Information on osteotomies, spring model and post-operative spring opening were recorded. For each patient, two preoperative models (PREOP) were created: i) CT model and ii) S model, created by processing patient specific 3D surface scans using population averaged skin and skull thickness and suture locations. Each model was imported into ANSYS Mechanical (Analysis System Inc., Canonsburg, PA) to simulate spring expansion. Spring expansion and cranial index (CI - skull width over length) at times equivalent to immediate postop (POSTOP) and follow up (FU) were extracted and compared with in-vivo measurements. Overall expansion patterns were very similar for the 2 models at both POSTOP and FU. Both models had comparable outcomes when predicting spring expansion. Spring induced CI increase was similar, with a difference of 1.2%±0.8% for POSTOP and 1.6%±0.6% for FU. This work shows that a simplified model created from the head surface shape yields acceptable results in terms of spring expansion prediction. Further modelling refinements will allow the use of this predictive tool during preoperative planning.

“3D surface scanner in Maxillofacial Surgery: State of the art.”

Physicians are used to having complementary studies that help us in all phases of our work. In the maxillofacial surgery field the most commonly used tests are radiological tests (CT and NMR) and digital clinical photographs.In recent years, the concept of 3D surgery has been developed and consists of the use of 3D technology applied to surgery. 3D surgery allows us to move from on-site planning of the surgery to pre-surgical planning, with a simulation and preview of the result at the bone and soft tissue level.Radiological studies are of very limited use in soft tissue planning and digital photography is two-dimensional and dependent on patient positioning. The use of the surface scanner solves these limitations as it computes the spatial coordinates of the patient's anatomical surface in order to create a 3D digital model.