Introduction to 3D Imaging Technologies for the Facial Plastic Surgeon

3D tools for surgery allow 3D analysis of images in a way that is meaningful to surgeons for increased insight and understanding of a patient’s anatomy. 3D analysis provides a way to see more than one plane at the same time in the same image. This article provides an introduction to 3D tools in the field of facial plastic surgery in 2011, beginning with a look at where surgeons would like to be and what the “dream” device would look like.

An introduction to 3D tools in the field of facial plastic surgery in 2011 should start with a look at where we would like to be: What does the optimal facial plastic surgery 3D image dream machine look like? How close are we to having that?

The dream device would use a method of 3D imaging that would be quickly acquired, be consistently repeatable, and have no safety concerns for the patient. The imaging would yield sub-sub-millimeter 3D data, including skin surface and tone, underlying soft tissue and muscles, bone, and teeth. It would capture and store the patient’s 3D image, including all of their anthropometric data. The patient model could be viewed three-dimensionally from any angle and with any anatomic parts variably transparent. Through entering a few demographics, the facial appearance of the patient at various ages or weights could be displayed. The surgeon would be able to perform virtual surgery, and the healed results, incorporating the behavior of all underlying and surrounding tissues, would morph into view before the planning surgeon’s eyes. The results of surgery could be displayed for any selected period after the procedure. Although the results would have no more certainty than a weather prediction, the percentage probabilities of the displayed results would be given. Alternative surgical approaches could be attempted and the surgeon would be alerted as to which had the greatest risk. For discussion with the patient, it could demonstrate from any angle possible changes that might be accomplished with surgery and those that are not possible. The surgeon, in conjunction with the patient, could select the approach that might accomplish the goals in the safest and most predictable manor. It would then store the preoperative plan for viewing in the operating room.

All of this would be accomplished on a platform that would be economically accessible for wide distribution and have an optimized user interface.

I believe that most surgeons would agree that such a tool would be useful. I was anxious to find out, as I requested the 3D articles for this review of the current state of the art for 3D imaging, how close we have come to this dream scenario. The articles that follow show the great strides that have been made. How close are we? As the authors have reported, many of the prerequisites for development of the tool described have already been attained. However, most of the authors, although giving examples of the implementation of components of this vision, have also talked about the many unattained applications to be realized in the future.

3D tools for surgery allow 3D analysis of images in a way that is meaningful to surgeons for increased insight and understanding of a patient’s anatomy. What is meant by 3D analysis of images? There are actually many facets to what 3D analysis can do. Put simply, it is a way to see more than one plane at the same time in the same image, although this does not always mean having a stereoscopic view. When we close one eye we do not see in 3D. But if we move around an object while looking with one eye we take in more data than a single plane. When we look in a mirror, we are looking at a flat surface but are receiving 3D information. When facial data is collected in an instant using a 3D stereophotogrammetric camera, information is stored that tells more than just the skin tones present in a single plane. 3D analysis tools allow viewing the image data from various points in space to see the changing contours and tones of a surface. When a CT is performed, data are collected, forming a cloud of data points in a cube or cylinder. 3D tools can be used to show internal anatomy in cut volumes and shaded surfaces, or even to navigate virtual endoscopic pathways through this volume of data, therefore providing an added dimension in understanding of the presurgical map of a patient’s anatomy. It means new surgical tools that allow things to be accomplished that could not previously. The articles in this issue describe these 3D tools and others that have proven to be useful in facial plastic surgery. Other applications continue to be discovered.

How did we get to where we are in the field of 3D image analysis and visualization?

It is on the shoulders of giants in 3D image analysis like Dr Richard Robb that current 3D developers stand. Dr Robb and his team developed 3D tools, always working a step ahead of what the computer hardware and software were capable of accomplishing. As computer technology and speed advanced exponentially, so did their ability to realize their vision. At a time when conventional acquisition of a single CT slice took 60 seconds, they were able to acquire and render CT data to show a beating heart. But the software tools to take multiple beams of CT data and create a 3D object had to be created from scratch. Many of the tools they developed are now in common use in this field, including in their own Analyze software (Analyze 10.0, Mayo Biomedical Imaging Resource, Rochester, MN, USA). A single example of their multitude of contributions is the 3D icon that is seen in displays showing the orientation of the view. These tools laid the groundwork for what is seen today in the 3D renderings that have been a common part of, for example, most facial trauma practices.

Some themes prevail throughout these articles. One is the inadequacy of measurements or analysis done in 2D. Comparing image analysis in 3D with that performed in two dimensions is analogous to comparing the impact of viewing a sculpture with viewing a drawing of the same subject. Everything surgeons do is in 3D, resulting in 3D changes in tissue. Whether the surgery is reconstructive or purely aesthetic, being able to plan in 3D or execute with 3D guides using premanufactured 3D templates or prostheses, or even image guidance, can be invaluable. It also can make surgeons more efficient, surgery safer, and anesthesia shorter.

Another prevailing theme is the desire of facial plastic surgeons to have an optimal method to objectively assess their results and help discover what surgical techniques are most beneficial for different types of pathology or patients. This vision raises the question of whether improved methods of analysis will bring us closer to understanding what makes a face “attractive.” Dr Richard Jacobson, who has extensive experience with 3D analysis of imaging data, including from cone beam imaging, has noted that the “average” or “normal” features that are present in people are not necessarily what makes them be considered beautiful or striking (Jacobson Richard, personal communication, 2011). Whether 3D analysis allows better portrayal of the elements of appearance that result in a given individual’s favorable aesthetic attributes remains to be reported.

We are in the early stages of many future articles objectifying the difference that 3D technology can make in outcomes, such as surgeon satisfaction, patient satisfaction, operative results, operative time, and costs. Several of the articles summarize the current state of outcomes studies in this field.

What lies ahead? We have all seen the exponential changes in personal computing. We have far greater computing capability in our cell phone than was used to land men on the moon. Inexpensive home computers have more 3D graphics processing capability than workstations of a few years ago. These advancements should all be favorable for accelerating the arrival of the dream machine in its ultimate form. If a fraction of the resources that are needed to create a single video game or movie special effect were dedicated to refining and expanding 3D image analysis tools, we would have the dream machine today. I hope you enjoy reading these articles and seeing where we are today in the field of 3D imaging technologies for facial plastic surgery.

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