Safety and Utility of Functional Dynamic Cervical Spine Radiographs in Select Subaxial Cervical Injury With Incomplete or No Neurological Deficit: Hybrid Retrospective and Prospective Observational Study

Study DesignHybrid retrospective and prospective observational study.ObjectivesTo evaluate the safety and clinical utility of Functional Dynamic Cervical Spine Radiographs (FDCSR) under supervision in assessing instability of subaxial cervical spine in non-obtunded cervical spine trauma patients with incomplete or no neurological deficits.MethodsWe reviewed records and radiographs of patients with traumatic cervical spine injury from January 2014 to December 2017 (retrospectively) and January 2018 to December 2018 (prospectively). Inclusion criteria: (1) Patients with intact neurology and stable injuries on static radiographs (<11° angulation, <3.5 mm translation) who underwent FDCSR; (2) Patients with neurological deficits and degenerative/congenital canal stenosis without discernible injuries on static radiographs, suggestive of hyperextension injuries. Outcomes assessed included X-ray adequacy, pre- and post-procedure neurological status, pain/spasm during imaging, and evidence of instability.ResultsOf 6890 patients evaluated, 364 met inclusion criteria (258 retrospective, 86 prospective). Pre-FDCSR neurological status was AIS-B (1.1%), AIS-C (8%), AIS-D (12.6%), and normal (78.3%). No neurological deterioration occurred post-FDCSR. X-rays were adequate in 202 cases (55.5%) and inadequate in 162. Instability was detected in 4.95% of adequate (n = 10) and 11.7% of inadequate (n = 19) FDCSR studies, with an overall instability rate of 7.97% (n = 29).ConclusionsFDCSR, when performed under appropriate supervision, is a safe and effective adjunct for detecting cervical spine instability in select trauma patients. It can identify occult instability even in suboptimal studies, supporting its utility in the evaluation of patients with equivocal findings on static imaging.