ORIGINAL ARTICLE The Virtual Nose A 3-Dimensional Virtual Reality Model of the Human Nose A. John Vartanian, MD; Joi Holcomb, MA; Zhuming Ai, PhD; Mary Rasmussen, MA; M. Eugene Tardy, MD; J. Regan Thomas, MD Background: The 3-dimensionally complex interplay Results: Anatomically correct 3-D model of the nose of soft tissue, cartilaginous, and bony elements makes the was produced. High-resolution images of the “virtual mastery of nasal anatomy difficult. Conventional meth- nose” demonstrate the nasal septum, lower lateral car- ods of learning nasal anatomy exist, but they often in- tilages, middle vault, bony dorsum, and other struc- volve a steep learning curve. Computerized models and tural details of the nose. Also, the model can be com- virtual reality applications have been used to facilitate bined with a separate virtual reality model of the face teaching in a number of other complex anatomical re- and its skin cover as well as the skull. The user can gions, such as the human temporal bone and pelvic floor. manipulate the model in space, examine 3-D anatomi- We present a 3-dimensional (3-D) virtual reality model cal relationships, and fade superficial structures to of the human nose. reveal deeper ones. Methods: Human cadaveric axial cross-sectional Conclusions: The virtual nose is a 3-D virtual reality (0.33-mm cuts) photographic data of the head and model of the nose that is accurate and easy to use. It can neck were used. With 460 digitized images, individual be run on a personal computer or in a specialized vir- structures were traced and programmed to create a tual reality environment. It can serve as an effective teach- computerized polygonal model of the nose. Further ing tool. As the first virtual reality model of the nose, it refinements to this model were made using a number establishes a virtual reality platform from which future of specialized computer programs. This 3-D computer applications can be launched. model of the nose was then programmed to operate as a virtual reality model. Arch Facial Plast Surg. 2004;6:328-333 HE DECEPTIVELY SIMPLE EX- intraoperative observations. Many out- ternal shape of the human standing textbooks and nasal anatomy at- nose belies the complexity lases exist, and are usually the first edu- and individual variability of cational tools used in teaching anatomy.1-4 its underlying anatomy. Nevertheless, textbooks can be limited by TThe shape of human nose is formed by the the artist’s or photographer’s perspec- interplay of osseous, cartilaginous, and soft tive. Even texts with the highest level of tissue elements. The manipulation of this accuracy and image quality are limited by structural scaffolding is the primary mo- the 2-dimensional nature of printed ma- dality used to effect change in rhino- terial, which cannot impart 3-dimension- plasty. As such, an accurate and clear un- ality. Video material is similarly limited by derstanding of the anatomy of the human not being able to deliver a 3-dimensional From the Division of Facial nose is a prerequisite for the rhinoplasty (3-D) experience. Another limitation of Plastic and Reconstructive surgeon. A firm grasp of nasal anatomy most traditional methods of learning Surgery, Department of early in a rhinoplasty surgeon’s career can anatomy relates to their distinct lack of any Otolaryngology–Head and minimize negative consequences of mas- interactivity and feedback. Neck Surgery (Drs Vartanian, tering the “learning curve.” As a supplement to knowledge gained Tardy, and Thomas), and the Traditional methods of learning from books and observation, cadaver dis- School of Biomedical and anatomy have helped generations of sur- sections can play an important role in the Health Information Sciences (Mss Holcomb and Rasmussen geons familiarize themselves with nasal mastery of anatomy. Unfortunately, lim- and Dr Ai), University of anatomy. These learning modalities have ited availability and high cost limit the use Illinois at Chicago; and the included anatomy atlases, textbooks or lit- of cadavers in most teaching institutions. Lasky Clinic, Beverly Hills, erature descriptions, cadaver dissections, Even when cadavers are available, learn- Calif (Dr Vartanian). lectures by rhinoplasty experts, videos, and ing from cadaver dissection is limited by (REPRINTED) ARCH FACIAL PLAST SURG/ VOL 6, SEP/OCT 2004 WWW.ARCHFACIAL.COM 328 ©2004 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/27/2021 the poorly delineated anatomical structures, by dissec- tion planes that have been altered by chemical preserva- tion, and by the relatively brief time (typically) spent in the dissection laboratory. For most surgeons, the mastery of 3-D nasal anatomy is still largely dependent on extensive intra- operative experience. Observation during rhinoplasty is an effective way for many beginning rhinoplasty surgeons to learn nasal anatomy. Clearly, there is no substitute for the knowledge that is gained after hav- ing performed a large number of rhinoplasties through dissection, tactile appreciation, and manipulation of nasal structures. It is precisely this intimate under- standing of nasal anatomy that the physician-in- training or the beginning rhinoplasty surgeon may be lacking. In such cases, virtual reality teaching tools aimed at teaching 3-D nasal anatomy with interactive capabilities could be particularly useful. Computerized anatomical models and virtual real- ity applications have been used to facilitate teaching in Figure 1. On axial cross sections, individual structures are traced and a number of other complex anatomical regions.5-7 Vir- labeled in a process called modeling and segmentation. tual reality models of the human temporal bone and the pelvic floor have already demonstrated the great poten- initial models were made using advanced 3-D modeling soft- tial of such teaching tools at our institution. In line with ware applications. our desire to create a 3-D virtual reality model of the hu- The surrounding bony craniofacial structures were pro- man nose and its surrounding structures, we set out to duced in a separate project and made compatible with the vir- tual nose for added functionality. Further refinements to the produce the “virtual nose.” models were made using computer modeling programs to im- prove surface detail. Small variations in scale were adjusted be- METHODS fore our 3-D nasal model was combined with our 3-D skull model. This final computer model of the nose was then pro- DATA ACQUISITION grammed to operate as a virtual reality application. The models were incorporated into the virtual reality en- Our goal was to create an accurate virtual reality model based vironment using an original set of modular software program- on anatomical data and observations. We based our model on ming tools.8 A number of computing tools were utilized to en- a freshly frozen female cadaver from the Visible Human Project able our model to function in a virtual classroom with (National Library of Medicine, Bethesda, Md). The head and audiovisual interaction and feedback. The application was pro- neck of the cadaver had been previously cut into fine (0.33- grammed on a commercially available graphics supercom- mm) axial cross sections and photographed. These high- puter (Silicon Graphics Onyx2; Silicon Graphics Inc, Moun- resolution color photographs had been digitized and were avail- tain View, Calif). A second set of final models was also simplified able as a set of consecutive images. Several other cadaver sources for viewing on personal computers as virtual reality modeling were closely evaluated. We chose to use this set of cadaver axial language–based models. cross sections because it provided (1) thin cross sections (0.33 mm), (2) frozen cadaver sections with minimal tissue distor- RESULTS tion, (3) high-resolution images of the cross sections, (4) cor- responding computed tomographic data from the cadaver’s skull A 3-D virtual reality model of the human nose and sur- and cervical spine, and (5) relative ease of visualization of dif- rounding structures was created. The virtual nose dem- ferent structures on cross-sectional analysis. Our data set con- onstrates the following anatomical structures: lower lat- sisted of 460 consecutive axial cross sections (0.33-mm cuts) eral cartilages, upper lateral cartilages, osseous nasal vault, of the midface and nose. nasal septum, and overlying skin cover (Figure 2 and PREPARATION OF DATA Figure 3). Also, the compatibility of the virtual nose with a separately produced craniofacial model allows the user The basic principle used involved combining hundreds of de- to inspect the skull and cervical spine.9 The virtual nose tailed and properly aligned 2-dimensional anatomical cross sec- is most functional when it is viewed in a virtual reality tions to generate a polygonal 3-D model. Each image was traced environment. The model was also programmed to run using computer software to outline the structures of interest. on a personal computer and displayed on a high- Individual structures were traced and given structure-specific resolution computer monitor. color codes at each axial level (n=460) (Figure 1). VIRTUAL REALITY VIEWING MODEL CREATION The set of “tracings” were saved as a set of images that were Viewing the model in a 3-D virtual reality environment stacked, combined, and used to create 3-D models. Using a spe- greatly enhances the model’s interactivity and useful- cialized computer, several 3-D polygonal models of nasal and ness as a teaching tool. The virtual reality images can be midface structures were produced. Further refinements to these generated a number of ways. We used a virtual reality (REPRINTED) ARCH FACIAL PLAST SURG/ VOL 6, SEP/OCT 2004 WWW.ARCHFACIAL.COM 329 ©2004 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 09/27/2021 A B C D Figure 2. Different views of the cartilaginous nasal structures in the “virtual nose.” display system called an ImmersaDesk (Board of Trust- movement around the 3-D model to generate different ees, University of Illinois at Chicago) to facilitate 3-D view- points of view of the model.