Harnessing 3-D Imaging for Children with Musculoskeletal Conditions

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Orthopaedics Update

3D Imaging of the Spine Our team uses EOS imaging to create 3-dimensional reconstructions of the spine, such as the one pictured above. The Children’s Hospital of Philadelphia has always been committed to using cutting- edge technology in patient treatment and monitoring. The Division of Orthopedics’ increased use of EOS 3-D technology reinforces that commitment by providing the safest, lowest possible radiation dose in pediatric radiographs while also allowing us to provide the best imaging services to patients.

EOS delivers 3 to 4 times less radiation than X-ray and about 20 times less radiation than basic CT scans. This is a significant decrease in radiation dose over time for patients with conditions like scoliosis, who typically undergo scans every 3 to 6 months, and up to 20 or more over the course of treatment. EOS’ head-to-toe imaging of a child in a standing, weight-bearing position and capability of generating the 3-D shape of the bone provides a more comprehensive view of how an orthopedic condition affects a child’s musculoskeletal system, particularly the spine and lower limbs.

“Medical diagnostics greatly rely on 2-D X-rays in orthopedics,” says Saba Pasha, PhD, MS, a researcher in CHOP’s Division of Orthopedics who has a background in biomedical engineering. “The true nature of 3-D bone deformity and alignment cannot be captured on X-rays. This may adversely affect patients’ treatment.”

EOS can calculate upwards of 100 clinical parameters. This data enables more accurate assessments pre-operatively, as well as critical review of results post-operatively to determine the effectiveness of a given intervention, compare outcomes, and revise approaches if warranted.

Our program is one of only a handful in the country using EOS to diagnose and evaluate treatment strategies, and one of an even fewer number doing EOS-focused clinical research. Pasha is currently involved in a multicenter study with the Harms Study Group to come up with a 3-D classification of the spino-pelvic alignment in scoliosis, as well as a clinical trial to create national guidelines for patient positioning in EOS. She also recently received a grant from the Scoliosis Research Society to study the use of 3-D parameters to specify whether a patient would benefit from selective spinal fusion or whole spine fusion.

The use of EOS in orthopedics has mostly focused on scoliosis—a 3-D condition that impacts the morphology and alignment of the spine, pelvis, and ribcage in the sagittal and frontal planes, vertebral rotation in the transverse plane, rib cage distortion, pelvis asymmetry, rotation, and obliquity. Pasha is using EOS to study the biomechanical origins of these problems and their impact on the overall posture and equilibrium of the scoliotic patients, as well as the impact of the surgical spinal correction on the biomechanical loading of the spinal vertebrae.

Patients who undergo spinal surgery are evaluated before and after surgery to determine the effect of surgery on their postural balance. Patients stand on a piezoelectric pressure mat, which measures dynamic pressure, while the EOS takes bi-planar X-rays of their musculoskeletal system. The combination of these 2 systems provides a comprehensive tool to not only see the local impact of the surgery but also get an overall picture of how the whole musculoskeletal system compensates/ reacts to the deformity before surgical intervention.

“Matching a pressure mat with an X-ray system, although simple, adds a lot to our understanding of the development of a musculoskeletal condition and its impact on a patient’s quality of life,” says Pasha. “Among other things, a key benefit is increased convenience to the patient and family, as you can evaluate morphology and dynamic pressure at the same time.”

Pasha and her team also now use the technology to image diagnoses beyond scoliosis, namely lower limb musculoskeletal deformities such as hip dysplasia, osteochondritis of the knee, and leg deformities, which can benefit from this new imaging modality. Three dimensional analysis and measurements in clinical evaluation and surgical planning of lower limb conditions will advance patient care and potentially expand our understanding of how lower limb conditions develop and progress, which will help us make more informed decisions regarding a patient’s treatment.

Pasha’s hope is that a better understanding of 3-D parameters in pediatric musculoskeletal deformities will provide additional insights that may assist in surgical planning. This knowledge will help determine the parameters that should be collected before and after surgery to quantitatively compare patient outcomes.

“The concept of 3-D analysis of musculoskeletal conditions in orthopedics is new; we are barely at the tip of the iceberg of what it is capable of being used for and telling us about patients,” Pasha says. “The benefits in diagnosis and treatment planning are clear. My work now is to establish consistent 3-D parameters for use in the clinical setting. I believe future orthopedic care can significantly benefit from these parameters when these measures are used in routine clinical assessments and pre- and postsurgical evaluation. As a researcher with a great interest in 3-D biomechanical analysis, my work will be focused on transferring this knowledge to orthopedic clinics.”