A stereo-photogrammetric technology called 3dMD, which uses an array of highly sensitive cameras to image the entire body’s surface in a fraction of a second, has been found to generate accurate and reliable models of the torso to help guide the management of adolescents with scoliosis.
The findings, presented at the 2022 Annual Meeting of the American Academy of Orthopaedic Surgeons, show that the ultrafast cameras produce scans of the body’s surface that complement internal images generated by low-dose radiographs. And because 3dMD does not rely on ionizing radiation, the technology may help scoliosis patients avoid many of the repeated and potentially harmful radiographs that conventional care requires.
A Fuller Picture of Scoliosis
Roger F. Widmann, MD, Chief of the Pediatric Orthopedic Surgery Service at Hospital for Special Surgery and the senior researcher on the study, noted that surface topography and internal imaging work together to provide a much fuller picture of how scoliosis affects the body.
“When you see someone with a spinal deformity, you’re not necessarily visualizing the shape of the spine underneath,” he said. “Three-dimensional surface scanning is analogous to what you see visually, whereas [radiographs] or MRI are often much different from what you see on the surface. Both approaches are important, but the information they provide is quite different.”
The 30-camera array can generate a full image of a standing person in under 2 milliseconds, fast enough to eliminate any blurring from even the slightest movement in any direction.
“It gives us very accurate information to begin with, and it’s important to start with sound data,” said Howard J. Hillstrom, PhD, a biomechanical engineer at Hospital for Special Surgery and co-principal investigator on the study.
Dr. Hillstrom, who describes the image as a “large, 3-D selfie,” added that these results “give us the green flag to study spinal pathology and the effects of treatments for different severities of scoliosis” in ways that weren’t possible previously. For clinicians, “It’s great to have objective tools to support the patient-reported outcomes that we use.”
3-D Scans Are Highly Reliable
What was previously unknown was how well these images of the body’s surface conform to the anatomy beneath the skin. This relationship is critical for 3dMD to be useful as a guide for scoliosis treatment in the clinic.
For the study, the researchers compared images gathered by 3dMD with those produced by a next-generation radiographic system called EOS. A total of 46 youths participated in the study, 26 of whom had been diagnosed with adolescent idiopathic scoliosis (mean age, 14.7 years; 14 females, 12 males) and 20 controls who did not have the condition (mean age, 14.6 years; 9 females, 11 males).
The 3dMD images demonstrated extremely high reliability, particularly for linear geometric measurements of the surface of the subjects.
“The measurements generated from the 3-D scans were used to create unique volumetric measures of truncal asymmetry, which demonstrated very high correlations with patient-reported self-image,” Dr. Widmann said.
Dr. Hillstrom noted the post-processing software that employs artificial intelligence (AI) is the secret behind the accuracy of the camera array. “AI fills in the blanks very quickly. It helps to identify anatomical regions and provide a mathematical approach to organizing the topographic data, showing you the head, neck, trunk and pelvis from outside of the body.
“You can uncover details you wouldn’t normally be able to see with the naked eye or with the use of conventional radiology.”
Predicting Outcomes of Surgery
As the 3dMD system moves into the clinic, the technology will help surgeons better predict both the cosmetic and functional outcomes of the various procedures for scoliosis.
“You can use the system to assess the efficacy of different surgical techniques based on how well you’re creating symmetry of the surface of the torso,” Dr. Widmann said. “This technology offers a quick and easy way to objectively assess surface symmetry as well as global spine range of motion, and both measures are really important to assess after scoliosis surgery.”
Groisser BN, Hillstrom HJ, Thakur A, Morse K, Cunningham ME, Hresko MT, Kimmel R, Wolf A, Widmann RF. Assessment of Spinal Deformity and Scoliosis with a Novel Automated Artificial Intelligence Powered Workflow Generates a Highly Reliable Suite of Whole-Body Surface Topographic Measurements (Poster P0855). Presented at the American Academy of Orthopaedic Surgeons’ 2022 Annual Meeting, March 22-26, 2022, Chicago, Illinois.