Aaron Oliker

A Virtual Reality Atlas of Craniofacial Anatomy

Background: Head and neck anatomy is complex and represents an educational challenge to the student. Conventional two-dimensional illustrations inherently fall short in conveying intricate anatomical relationships that exist in three dimensions. A gratis three-dimensional virtual reality atlas of craniofacial anatomy is presented in an effort to address the paucity of readily accessible and customizable three-dimensional educational material available to the student of head and neck anatomy. Methods: Three-dimensional model construction was performed in Alias Maya 4.5 and 6.0. A basic three-dimensional skull model was altered to include surgical landmarks and proportions. Some of the soft tissues were adapted from previous work, whereas others were constructed de novo. Texturing was completed with Adobe Photoshop 7.0 and Maya. The Internet application was designed in Viewpoint Enliven 1.0. Results: A three-dimensional computer model of craniofacial anatomy (bone and soft tissue) was completed. The model is compatible with many software packages and can be accessed by means of the Internet or downloaded to a personal computer. As the three-dimensional meshes are publicly available, they can be extensively manipulated by the user, even at the polygonal level. Conclusions: Three-dimensional computer graphics has yet to be fully exploited for head and neck anatomy education. In this context, the authors present a publicly available computer model of craniofacial anatomy. This model may also find applications beyond clinical medicine. The model can be accessed gratis at the Plastic and Reconstructive Surgery Web site or obtained as a three-dimensional mesh, also gratis, by contacting the authors.

Designing a virtual reality model for aesthetic surgery.

Background: Aesthetic surgery deals in large part with the manipulation of soft-tissue structures that are not amenable to visualization by standard technologies. As a result, accurate three-dimensional depictions of relevant surgical anatomy have yet to be developed. This study presents a method for the creation of detailed virtual reality models of anatomy relevant to aesthetic surgery. Methods: Two-dimensional histologic sections of a cadaver from the National Library of Medicines Visible Human Project were imported into Aliass Maya, a computer modeling and animation software package. These two-dimensional data were then “stacked” as a series of vertical planes. Relevant anatomy was outlined in cross-section on each two-dimensional section, and the resulting outlines were used to generate three-dimensional representations of the structures in Maya. Results: A detailed and accurate three-dimensional model of the soft tissues germane to aesthetic surgery was created. This model is optimized for use in surgical animation and can be modified for use in surgical simulators currently being developed. Conclusions: A model of facial anatomy viewable from any angle in three-dimensional space was developed. The model has applications in medical education and, with future work, could play a role in surgi-cal planning. This study emphasizes the role of three-dimensionalization of the soft tissues of the face in the evolution of aesthetic surgery.

Creating a Virtual Surgical Atlas of Craniofacial Procedures: Part I. Three-Dimensional Digital Models of Craniofacial Deformities

Background: Three-dimensional digital animation can enable surgeons to create anatomically accurate, virtual models of normal and pathologic human anatomy. From these models, surgical procedures can be digitally performed, recorded, and distributed as a teaching tool or as a virtual surgical atlas. The idea of a virtual surgical atlas has recently become a part of contemporary surgical teaching. In the field of craniofacial surgery, no such educational tool exists. Presented is the first part of the creation of a virtual atlas of craniofacial surgical procedures: the three-dimensional digital modeling of pathologic deformities commonly treated by craniofacial surgeons. Methods: Three-dimensional craniofacial models were constructed using Maya 8.5. A skeletally “normal” craniofacial skeleton was first produced from a preexisting digital skull using Bolton tracings as a reference. The remaining soft-tissue elements were then added to create an anatomically complete three-dimensional face. The “normal” model was then deformed in Maya to produce specific craniofacial deformities using computed tomographic scans, cephalograms, and photographs as a reference. One of the craniofacial deformity models was created directly from computed tomographic data. Results: One model of the normal face and eight pathologic models of craniofacial deformities were created: microgenia, micrognathia, prognathia, temporomandibular joint ankylosis, maxillary hypoplasia, Crouzon syndrome with and without the need for cranial vault expansion, and bicoronal craniosynostosis. Conclusions: For the first time, anatomically accurate three-dimensional digital models of craniofacial deformities have been created. The models are the first step in the creation of a virtual surgical atlas of craniofacial procedures.

Creating a Virtual Surgical Atlas of Craniofacial Procedures: Part II. Surgical Animations

Background: Craniofacial surgery can be challenging to teach and learn. To augment the intraoperative learning experience for surgical trainees and to provide a resource for practicing craniofacial surgeons to review uncommonly performed procedures before entering the operating room, a series of three-dimensional animations were created encompassing the most commonly performed craniofacial procedures. Methods: Previously created three-dimensional craniofacial digital models were used to create digital animations of craniofacial surgical procedures using Maya 8.5. Digital models were altered systematically within Maya to recreate the ordered steps of each craniofacial procedure. Surgical tools were imported into Maya for use in the animations using computer-aided manufacturing files obtained directly from the manufacturer. Results: Nine craniofacial procedures were animated: genioplasty, bilateral sagittal split osteotomy, intraoral vertical ramus osteotomy, Le Fort I osteotomy, unifocal mandibular distraction, mandibular transport distraction, fronto-orbital advancement with cranial vault remodeling, Le Fort III advancement/distraction, and monobloc advancement/distraction. All major surgical steps are demonstrated, including exposure, execution of the osteotomy, displacement of the bone composite, and the predicted morphologic changes to the craniofacial contour. Throughout the surgical animation, the view of the surgeon in the operating room is incorporated to reproduce the vantage of the surgeon, and the overlying tissue is rendered transparent to illustrate critical underlying anatomical relationships. Conclusions: The first virtual surgical atlas of craniofacial procedures is presented. These animations should serve as a resource for trainees and practicing surgeons in preparation for craniofacial surgical procedures.

Computer-generated three-dimensional animation of the mitral valve

OBJECTIVE Three-dimensional motion-capture data offer insight into the mechanical differences of mitral valve function in pathologic states. Although this technique is precise, the resulting time-varying data sets can be both difficult to interpret and visualize. We used a new technique to transform these 3-dimensional ovine numeric analyses into an animated human model of the mitral apparatus that can be deformed into various pathologic states. METHODS In vivo, high-speed, biplane cinefluoroscopic images of tagged ovine mitral apparatus were previously analyzed under normal and pathologic conditions. These studies produced serial 3-dimensional coordinates. By using commercial animation and custom software, animated 3-dimensional models were constructed of the mitral annulus, leaflets, and subvalvular apparatus. The motion data were overlaid onto a detailed model of the human heart, resulting in a dynamic reconstruction. RESULTS Numeric motion-capture data were successfully converted into animated 3-dimensional models of the mitral valve. Structures of interest can be isolated by eliminating adjacent anatomy. The normal and pathophysiologic dynamics of the mitral valve complex can be viewed from any perspective. CONCLUSION This technique provides easy and understandable visualization of the complex and time-varying motion of the mitral apparatus. This technology creates a valuable research and teaching tool for the conceptualization of mitral valve dysfunction and the principles of repair.

An Internet-Based Surgical Simulator for Craniofacial Surgery.

8 up of 3.5 years (range 6.5 – 0.5 years), improvements in all functional outcomes were noted. Progressive re-innervation of facial skin and muscles improved or enabled eating, speaking and the ability to produce facial expressions and experience facial sensation. There was significant increase in upper airway volumes, leading to improvements in breathing and smelling. All artificial airways and feeding tubes were removed. In the remaining FT recipients from the peer-reviewed literature, the abilities to smell, eat and feel were improved in 100% of cases, whereas the abilities to breath, speak and grimace were ameliorated in 93%, 71% and 76%, respectively. Almost 60% of outcomes were not reported in the scientific literature.