The EOS 2D/3D imaging system can be used for many types of radiological examinations, but is likely to offer particular benefits for weight-bearing imaging, full-body imaging, simultaneous PA and lateral imaging, and 3D reconstruction, or where a reduced radiation dose is important.
The experts agreed that the most important applications of this technology for inclusion in the scope were the management of spinal deformities and lower limb problems such as leg length discrepancy, leg alignment and conditions that affect the hip and knee (notably hip and knee replacement planning).
The indications included in the scope can be divided into those affecting children and adolescents, and those affecting adults. Indications in children and adolescents included:
spinal deformity, principally scoliosis but also including other conditions such as Scheuermann's disease
leg length discrepancy and alignment.
Indications in adults included:
spinal deformity, including degenerative scoliosis, progressive kyphosis and osteoporotic fractures
loss of sagittal and coronal balance, including issues relating to the hips and knees for which full-body or full leg length images are currently requested.
The management of scoliosis and other spinal deformities involves repeated imaging, which leads to increased radiation exposure, a particular concern for children and adolescents. Leg length discrepancy and leg alignment problems in children and adolescents are often assessed and monitored with multiple images that may require 'stitching' together (that is, aligning and combining).
For adults, the principal spinal deformities are those associated with degenerative diseases that lead to arthritic changes, kyphosis or scoliosis. In some cases, problems resulting from adolescent scoliosis may appear with other symptoms in adulthood. Full leg and hip or full-body radiographs may be used to diagnose and manage degenerative conditions of the hips and knees, and may also be used to plan joint replacement.
During the initial phase of this assessment, the external assessment group (EAG) identified no evidence meeting the inclusion criteria for the review for some of the conditions that were initially included in the scope and, therefore, did not include these conditions in the diagnostics assessment report (see appendix C). These conditions included lordosis, acquired kyphosis, neurofibromatosis, osteoporotic fracture and issues relating to hip and knee replacement for which full-body or full leg length images are currently requested. In some cases, these conditions can be sufficiently severe to cause significant disability. According to clinical experts, lordosis is very rare on its own and is almost always associated with scoliosis. Therefore, the inclusion of scoliosis should encompass patients with lordosis secondary to scoliosis. Acquired kyphosis and neurofibromatosis were excluded because of high variability in patient groups and the relatively small numbers of patients needing surgery. Osteoporotic fracture was not considered because clinical experts advised that it is only rarely associated with spinal deformity.
In addition to the conditions included in the scope, the EOS system is capable of providing most images that are currently done with conventional radiography, the comparator.
The management of spinal deformity primarily involves monitoring at intervals to assess disease progression and guide treatment decisions. Progression is measured in terms of the degree of spinal curvature, which is typically monitored using serial X-rays in the upright weight-bearing position. The frequency of monitoring depends on the age of the patient, their rate of growth and the nature of the curvature. The frequency of monitoring for kyphosis and other deforming dorsopathies is broadly similar to that for scoliosis, which tends to range from every 4 months to almost 2 years. Patients are also monitored using X-rays in the weight-bearing position before surgery, for up to 2 years after surgery or up to the age of 20 years. Patients with congenital deformities of the lower limbs, hips or spine are likely to undergo surgery at a younger age than patients with scoliosis, kyphosis or other deforming dorsopathies. Therefore, X-ray monitoring for congenital deformities usually continues for a shorter period.
Imaging in the weight-bearing position is important for evaluating deformities of the spine because of the effect of gravity. The American College of Radiology Practice Guideline for the Performance of Radiography for Scoliosis in Children recommends PA and lateral radiography of the spine in an upright position for initial examination or for screening. Imaging in a non-weight-bearing position can lead to misinterpretation of images and misdiagnosis. Full-body images also provide information about the position of the pelvis and legs, and so help to avoid misinterpretation of the degree of spinal curvature.
Erect weight-bearing PA and lateral images of the spine and lower limbs are also used in adults to evaluate sagittal balance and spinal deformity (lordosis and kyphosis) as well as coronal plane deformity (scoliosis). According to NHS Hospital Episode Statistics, admissions for instrumental correction of deformity of the spine (code V41) have nearly doubled to 2,643 over the 5‑year period ending 2009/10.