Digital Radiographic Motion Analysis
Digital Radiographic Motion Analysis is the most accurate way to assess a patient’s spine for injuries sustained in a Motor Vehicle Accident. This type of study is the most accurate way to diagnose Whiplash, also called cervical acceleration–deceleration (or CAD) syndrome, which is a neck injury commonly caused by car accidents, falls, and contact sports. It results from a quick, jerking motion that forces the neck beyond its normal range of motion. This study can detect injuries that were missed at the ER and oftentimes missed by even the most skilled provider. Digital Radiographic Motion Analysis allows us to see what is termed Alteration of Motion Segment Integrity or AOMSI. This is a term described by the American Medical Association as a change in the biomechanical function of any two segments or vertebra in relation to their motion to the above or below segment, where there can be increased or decreased motion. After Cervical Acceleration-Deceleration (CAD) Injuries the ligaments in between the spinal vertebrae can be torn or damaged. This allows the vertebra or vertebrae to have too MUCH motion or hypermobility which can lead to facet injuries and if severe enough neurological symptoms in the hands and feet and the risk for paralysis.
Digital Radiographic Motion Analysis also allows us to assess a patient’s spine for loss of motion segment integrity (hereinafter referred to as LMSI) relates to the movement of two adjacent vertebral bodies as measured in flexion and extension. The “loss” in integrity relates to the alteration in movement such as a loss in range of motion or movement beyond what would be considered normal limits. Any significant loss in the range of motion or a gain beyond the acceptable normal range in the motion segment of the spine will result in an over-compromise of the adjacent levels of the spine. The adjacent levels will now be taxed beyond normal and the excessive wear and tear making the adjacent levels more susceptible to injury.
The use of Digital Radiographic Motion Analysis also allows us to determine possible impairment to the patient from their injuries. The diagnosis-related estimate (DRE) method is the principal methodology used to evaluate spinal AOMSI impairment in the fourth and fifth editions of the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides). In the AMA Guides, Sixth Edition, impairment ratings are calculated using the diagnosis-based impairment (DBI) method that uses five impairment classes determined by diagnoses and specific criteria, adjusted by consideration of non-key factors and grade modifiers. The following factors must be considered to determine if AOMSI is present: 1) flexion/extension radiographs are performed when the individual is at maximum medical improvement and are technically adequate; 2) the proper methodology is used in obtaining measurements of translation and angular motion; 3) normal translation and angular-motion thresholds consistent with the literature are used in determining AOMSI. Imaging modalities such as videofluoroscopy, digital fluoroscopy, and upright/motion magnetic resonance imaging cannot be used to establish an AOMSI permanent impairment using the AMA Guides. A number of technical factors can affect the image quality associated with measurements of AOMSI, including film centering, artifacts, poor edge resolution, endplate normal variations and spurring, and use of analog rather than digital radiography.