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Incranio-maxillofacialsurgeryphysiciansareoftenfaced with the reconstruction of massively destroyed or rad- ically resected tissue structures caused by trauma or tumours. Also corrections of dislocated bone fragments up to the complete modeling of facial regions in cases of complex congenital malformations are common tasks of plastic and reconstruc...
Contexts in source publication
Context 1
... constantly increasing public mobility with always faster transportation systems, as well as an increasing level of sport activities with all accidents that might result thereof lead to a growing number of complex fractures in the cranio-maxillofacial region. A surgeon’s pri- mary concern is to reconstruct the original sit- uation as close as possible. For that purpose photographs or any other source of information that documents the previous state is used. The functional and aesthetic rehabilitation of con- genital malformations, however, is much more difficult to achieve, since any individual recon- struction template is missing ( Fig. 1 ) . Especially for children or youths, the psychoso- cial consequences of an appearance, that is deviating from the respective standards, are of extremely high relevance for their personal development and the later social acceptance. Therefore, a surgeon has to model a functional anatomy under consideration of a harmonious facial appearance. Such a modeling task re- quires a high level of surgical expertise, a dis- tinct sense of aesthetics, artistic skills, and ex- tensive communication with the patients and their relatives. Due to the individuality of pa- tients, the complexity of anatomy and physiol- ogy of the human organism, as well as the de- mand for optimal functional and aesthetic reha- bilitation, cranio-maxillofacial surgery must ...
Context 2
... planned under utilization of all avail- able planning aids. Reliable methods and tools are needed to prejudge the overall result of facial surgery to its full extent. The surgical correction of facial disproportions requires profound knowledge of a normally de- veloped anatomy. Among many physiognomic investigations, Albrecht Dürer and Leonardo da Vinci already did accomplish elaborate studies on facial proportions and the characterization of harmonious faces, that even today still have its validity 1 ] . Meanwhile a comprehensive database of healthy or pathologic proportions as a result of anthropometric or cephalometric studies provide sufficient information for the characterization of anomalies 2, 3 ] . To as- sess an individual situation, anthropometric and cephalometric landmarks are identified on the skin surface as well as on X-ray images, and are set in relation to each other for a comparison to the normal range. Starting from anatomic landmarks and lateral or frontal X-ray images, cephalometric analysis is typically performed on 2D projections of 3D anatomy. Traditionally, contours, landmarks, distances, and angles were manually traced on radiographs using acetate overlays, and these tracings were copied, cut and rearranged. Later on, in the 1970’s, this process was adapted to a computer using a digitizer tablet and 2D im- age processing software 4 ] ( Fig. 2 ) . That way profile corrections could be planned, however, without any possibility to reliably assess impli- cations on the facial soft tissue. From the 1980’s on, computer-assisted planning methods have been developed that allow for a combined use of anthropometric and cephalo- metric landmarks to predict soft tissue pro fi les on the basis of heuristic ratios that have been observed over time 5 ] . Advanced image pro- cessing tools distort digital 2D profile images according to the estimated profile changes, lead- ing to a rough, but often grotesque approxima- tion of a patient’s postoperative appearance. For complex facial dysplasia, 2D planning meth- ods with profile analysis are generally not suffi- cient. Especially symmetry aspects, as in cases of hemifacial microsomia ( cf. Fig. 1, center ) , are only assessable in a frontal view. Thus, the goal should be to plan any complex facial surgery on a 3D model of a patient’s head, and to assess any changes in a 3D view from arbitrary perspectives. The prerequisites for a 3D planning are 3D imaging techniques, as available with computed tomography. Due to the high X-ray absorp- tion rate of bone, skeletal structures can almost automatically be reconstructed from a consec- utive set of CT slices. This layered, three- dimensional information can be converted to a life-size replica of a patient’s skull via so called rapid prototyping techniques ( Fig. 3 ) . On such models, surgeons are able to practically perform bone cuts ( osteotomies ) and bone relocations to preoperatively assess functional rehabilitation 6, 7 ] . However, rapid prototyping techniques are rather expensive, especially when different therapeutic concepts are to be evaluated. Fur- thermore, neither the impact of an osteotomy on vulnerable structures, like nerves, vessels or, for example, the roots of the teeth, nor the facial soft tissue arrangement resulting from bone relocations, can be assessed. These re- quirements are additional important reasons for computer-assisted planning methods in cranio- maxillofacial ...
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A broad overview is provided of the normal anatomy of the male genitalia to offer the best surgical outcomes in cases related to congenital abnormalities, trauma, cancer-related extirpation, and aesthetics. Neural and vascular anatomy is discussed in depth due to its critical role in maintaining function and in assuring tissue viability.
The medial wall and floor of the bony orbit are frequently fractured because of the delicate anatomy. To optimize functional and aesthetic results, reconstructive surgeons should understand the anatomy and pathophysiology of orbital fractures. Appropriate treatment involves optimal timing of intervention, proper indications for operative repair, in...
Reconstruction of large defects in the skull and scalp are a challenge for reconstructive surgeon. Several factors can influence the selection of a particular surgical method: anatomy of the defect, patient-dependent factors, surgeon preferences, etc. In unfavorable conditions such as large defects, presence of infection or previous surgery, microv...
Citations
... 30 The availability of computer-aided surgical techniques for diagnosis, virtual planning, and treatment of maxillofacial fractures allowed for individualized surgical fracture treatment minimizing the potential of postoperative pitfalls. 13,18,31 The 3DP-ZSSG managed to actively reduce the zygomatic bone into the virtually planned position with minimal mean deviation (ranging from zero to 0.6mm). This could be attributed to several reasons: 1) The three-dimensional spatial guidance of the 3GC's triangular orientation allowed 3D positioning of the zygomatic bone. ...
... Virtual planning also allows for multiple osteotomized segment movements, which are much more difficult in model surgery, to evaluate the effects of different movement designs on soft tissues. [24][25][26] For this purpose, it is essential to use the most accurate and precise methods at each step of virtual orthognathic surgery planning to obtain reliable results. Although different methods are used by various researchers to transfer the dentition clearly and accurately, there is no previous study in the literature that compares the accuracy and precision of these methods among themselves and with the conventional method, especially in 3D orthognathic surgery planning. ...
Objectives
The hard and soft tissues of the head and neck, dentition, and temporomandibular joint are the determining elements in orthognathic surgery planning. The accuracy and precision of the relationship between the jaws at the beginning of treatment and their final position depend on an accurate dentition record. The aim of this study was to determine the simplest and most feasible virtual dental model transfer method for three-dimensional orthognathic planning according to clinical applicability, technical difficulty, effective costs, accuracy, and precision.
Material and Methods
A total of ten spherical porcelain markers were placed in plaster models of the maxilla and mandible of a patient. The models were scanned using an intraoral optical scanner, an extraoral digital model scanner, and cone-beam computerized tomography. To evaluate reliability, each measurement was repeated 10 times at 1-week intervals and the distances between points were measured horizontally and vertically. The findings obtained in the study were evaluated statistically using IBM SPSS Statistics 2.2 program.
Results
Measurements obtained with the extraoral model scanner did not differ from the digital caliper method ( P > 0.05), while there were significant differences between the digital caliper and the other methods (intraoral 3D scanner P = 0.000; CBCT P = 0.001).
Conclusion
Although all of the measurements showed high consistency among all methods, the most accurate results were obtained with the extraoral digital model scanner. (r = 0.99, P = 0.01, P < 0.05).
... Zwang et al. [14] have used generalised and mean Hausdorff distance for character recognition. Zachow et al. [15] have used Hausdorff distance measure in computer-assisted planning for improved surgical preparation. Espinace et al. [16] have used Modified Hausdorff Distance in robot movements by finding the distance between the expected line segments the robot should sense and the line segments extracted from actual measurements using a range finder. ...
We propose a novel distance measure called Modified Complement Weighted Sum of Minimal Distance (MCWSMD) for image registration. We have conducted experiments by adding different types of noise on the grayscale images, medical images and on the face dataset. We further evaluated performance on synthetic images and then compared the results with other existing methods and found that MCWSMD outperforms the other distance based methods.
... With the fast development of science and technology, computer-assisted surgery becomes the necessary supportive tool for diagnosis, operation planning, and treatment in medicine services [2][3][4][5]. In clinical routine, surgeons have been already supported by various computer-assisted devices such as the 3D reconstruction system, preoperative planning system, and intraoperative navigation system, especially the navigation system, which has brought great convenience for surgery and attracted increasing attentions. ...
In view of the characteristics of high risk and high accuracy in cranio-maxillofacial surgery, we present a novel surgical robot system that can be used in a variety of surgeries. The surgical robot system can assist surgeons in completing biopsy of skull base lesions, radiofrequency thermocoagulation of the trigeminal ganglion, and radioactive particle implantation of skull base malignant tumors. This paper focuses on modelling and experimental analyses of the robot system based on navigation technology. Firstly, the transformation relationship between the subsystems is realized based on the quaternion and the iterative closest point registration algorithm. The hand-eye coordination model based on optical navigation is established to control the end effector of the robot moving to the target position along the planning path. The closed-loop control method, “kinematics + optics” hybrid motion control method, is presented to improve the positioning accuracy of the system. Secondly, the accuracy of the system model was tested by model experiments. And the feasibility of the closed-loop control method was verified by comparing the positioning accuracy before and after the application of the method. Finally, the skull model experiments were performed to evaluate the function of the surgical robot system. The results validate its feasibility and are consistent with the preoperative surgical planning.
... Orthodontic surgery corrects congenital or acquired deformations of the skull and face, including maxillofacial deformities, congenital malformations and deformations of the jaw joint. Implant treatment is important in orthodontic surgery, since it enables the replacement of natural teeth (Xia et al., 2000;Xia et al., 2005;Zachow et al., 2006;Swennen et al., 2007). Although the success of technical aspects is important in dental surgery, effective management of the treatment schedule is also essential, since a dentist must consider the intermediate results in determining treatment prognosis. ...
In dental implant treatment or corrective surgery, a dental plaster model is produced to recognize the shape of the teeth. Understanding this dentition model is an important issue in prosthetic dentistry and craniomaxillofacial surgery. However, dental models are time consuming and costly to produce via traditional casting methods. We provide a method which makes dentition model from both a positive and a negative dental impression. Also we produce a system for making a digital dentition model using computed tomography (CT) data during the impression process. Additionally, the system allows the digital dentition model to be realized via a three-dimensional printer. The result simplifies production of the dentition model, since a physical model can be produced directly from an impression of the patient. Our system can simplify the dentition process and treatment intervention involved in making a dentition model. The digital model enables clinicians to manage the patient’s cumulative data and to predict changes during the course of treatment.
... Craniomaxillofacial (CMF) surgery [1]- [3] corrects the congenital and acquired deformities of the skull and face. Throughout the world, many patients suffer from these deformities and require surgical correction [4]- [6]. ...
Partially edentulous dentition presents a challenging problem for the surgical planning of digital dental occlusion in the field of craniomaxillofacial surgery because of the incorrect maxillomandibular distance caused by missing teeth. We propose an innovative approach called Dental Reconstruction with Symmetrical Teeth (DRST) to achieve accurate dental occlusion for the partially edentulous cases. In this DRST approach, the rigid transformation between two symmetrical teeth existing on the left and right dental model is estimated through probabilistic point registration by matching the two shapes.With the estimated transformation, the partially edentulous space can be virtually filled with the teeth in its symmetrical position. Dental alignment is performed by digital dental occlusion reestablishment algorithm with the reconstructed complete dental model. Satisfactory reconstruction and occlusion results are demonstrated with the synthetic and real partially edentulous models.
... This method shares some features with other studies concerning the comparison between pre-and postoperative results in CMF surgery. 22 The accuracy of the procedure was determined comparing the preoperative simulation with the postoperative CT scan, using two parallel methods: (1) the Hausdorff distance algorithm for a 3D surface analysis and (2) a geometrical pointbased analysis. ...
This article aims to determine the absolute accuracy of maxillary repositioning during orthognathic surgery according to simulation-guided navigation, that is, the combination of navigation and three-dimensional (3D) virtual surgery. We retrospectively studied 15 patients treated for asymmetric dentofacial deformities at the Oral and Maxillofacial Surgery Unit of the S.Orsola-Malpighi University Hospital in Bologna, Italy, from January 2010 to January 2012. Patients were scanned with a cone-beam computed tomography before and after surgery. The virtual surgical simulation was realized with a dedicated software and loaded on a navigation system to improve intraoperative reproducibility of the preoperative planning. We analyzed the outcome following two protocols: (1) planning versus postoperative 3D surface analysis; (2) planning versus postoperative point-based analysis. For 3D surface comparison, the mean Hausdorff distance was measured, and median among cases was 0.99 mm. Median reproducibility < 1 mm was 61.88% and median reproducibility < 2 mm was 85.46%. For the point-based analysis, with sign, the median distance was 0.75 mm in the frontal axis, -0.05 mm in the caudal-cranial axis, -0.35 mm in the lateral axis. In absolute value, the median distance was 1.19 mm in the frontal axis, 0.59 mm in the caudal-cranial axis, and 1.02 mm in the lateral axis. We suggest that simulation-guided navigation makes accurate postoperative outcomes possible for maxillary repositioning in orthognathic surgery, if compared with the surgical computer-designed project realized with a dedicated software, particularly for the vertical dimension, which is the most challenging to manage.
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.
... Mobilized segments of the digital skull model can be freely positioned to assess a modified facial skeleton with respect to natural proportions, symmetry, functional rehabilitation, 19 as well as a harmonious facial appearance under consideration of facial soft tissue. 21,22 The spatial transformation of mobilized bone segments can be interactively applied via standard techniques of 3D computer graphics and humancomputer interaction (HCI). Parts can be translated in 3D space or rotated around a predefined center or axis (►Fig. ...
This article reflects the research of the last two decades in computational planning for cranio-maxillofacial surgery. Model-guided and computer-assisted surgery planning has tremendously developed due to ever increasing computational capabilities. Simulators for education, planning, and training of surgery are often compared with flight simulators, where maneuvers are also trained to reduce a possible risk of failure. Meanwhile, digital patient models can be derived from medical image data with astonishing accuracy and thus can serve for model surgery to derive a surgical template model that represents the envisaged result. Computerized surgical planning approaches, however, are often still explorative, meaning that a surgeon tries to find a therapeutic concept based on his or her expertise using computational tools that are mimicking real procedures. Future perspectives of an improved computerized planning may be that surgical objectives will be generated algorithmically by employing mathematical modeling, simulation, and optimization techniques. Planning systems thus act as intelligent decision support systems. However, surgeons can still use the existing tools to vary the proposed approach, but they mainly focus on how to transfer objectives into reality. Such a development may result in a paradigm shift for future surgery planning.
Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.
... In recent years, due to the expanding application of computer in medicine, computer assisted surgery is widely used as supportive tools for diagnosis, operation planning, and treatment in surgical intervention [5][6][7][8]. In clinical routine, the surgeon has been already supported by various computer aided devices such as surgical planning systems, intraoperative navigation systems, and stereolithographic modeling of the patient's skull, especially the navigation system, which has largely improved the surgical result. ...
... As a result, controlling the robot to a certain position could be realized, as long as the corresponding parameters are described in the robot space. (5) , which is the transformation matrix from patient space to robot space, is calculated by and as follows: ...
The three-arm surgical robot system assisted mandible reconstruction surgery (TMR-MRS) is developed to repair the mandible defects caused by congenital defect, trauma, or acquired disease. The surgical robot system is divided into four parts, including 3D reconstructed image subsystem, robotic subsystem, optical measurement subsystem, and patient subsystem. The spatial registration based on quaternion is proposed to obtain the transformation relationship between four surgical subsystems. A method of hand-eye coordination is presented to control the end-effector of the robot arm to target position according to surgical planning. A least square error criterion is developed to optimize and compensate the hand-eye coordination method. In addition, the position of fibular implant in the robot space is calculated when it is grasped by end-effector of robot middle arm. Finally, the positioning accuracy tests and skull model experiments were conducted to evaluate the function of the surgical robot system. The results validate its feasibility and are consistent with the preoperative surgical planning.
... Physics-based soft-tissue simulation approaches often focus on either efficiently producing realistic-looking animations for computer graphics applications [1,2] or simulating models with high physical accuracy for studying soft-tissue behaviour [3,4] or surgical simulation [5,6]. The former simulates large areas, such as the face, with just enough physics to efficiently produce the desired realism of animations. ...
... On the other hand, applications with high accuracy requirements often use much more detailed physics-based models accurately to simulate small areas, such as a block of skin for wrinkle simulation [4,18], or they involve small deformations [5,19]. These approaches are normally required to use the more accurate but computationally complex finite element (FE) method [3,6], or the FE-based but precomputation-heavy mass-tensor (MT) method [20,21]. When modelled, they often simulate muscles [18,22] and wrinkles [3,4] in a physics-based manner. ...
... Muscle activations can be estimated from performance-capture data to drive FE facial models [25,34]. However, because of its computational cost, the FE method is mainly used with scientific [19,35] or surgical applications [5,6] that require high accuracy, which normally use simple linear isotropic constitutive models to simulate small displacements. The linear MT method has also been used for simulating small displacements with such applications [20,36]. ...
Physically-based animation techniques enable more realistic and accurate animation to be created. We present a fully physically-based approach for efficiently producing realistic-looking animations of facial movement, including animation of expressive wrinkles. This involves simulation of detailed voxel-based models using a graphics processing unit-based total Lagrangian explicit dynamic finite element solver with an anatomical muscle contraction model, and advanced boundary conditions that can model the sliding of soft tissue over the skull. The flexibility of our approach enables detailed animations of gross and fine-scale soft-tissue movement to be easily produced with different muscle structures and material parameters, for example, to animate different aged skins. Although we focus on the forehead, our approach can be used to animate any multi-layered soft body. Copyright © 2013 John Wiley & Sons, Ltd.
