Maximum movement and cumulative movement (travel) to inform our understanding of secondary spinal cord injury and its application to collar use in self-extrication

Abstract

Background Motor vehicle collisions remain a common cause of spinal cord injury. Biomechanical studies of spinal movement often lack “real world” context and applicability. Additional data may enhance our understanding of the potential for secondary spinal cord injury. We propose the metric ‘travel’ (total movement) and suggest that our understanding of movement related risk of injury could be improved if travel was routinely reported. We report maximal movement and travel for collar application in vehicle and subsequent self-extrication. Methods Biomechanical data on application of cervical collar with the volunteer sat in a vehicle were collected using Inertial Measurement Units on 6 healthy volunteers. Maximal movement and travel are reported. These data and a re-analysis of previously published work is used to demonstrate the utility of travel and maximal movement in the context of self-extrication. Results Data from a total of 60 in-vehicle collar applications across three female and three male volunteers was successfully collected for analysis. The mean age across participants was 50.3 years (range 28–68) and the BMI was 27.7 (range 21.5–34.6). The mean maximal anterior–posterior movement associated with collar application was 2.3 mm with a total AP travel of 4.9 mm. Travel (total movement) for in-car application of collar and self-extrication was 9.5 mm compared to 9.4 mm travel for self-extrication without a collar. Conclusion We have demonstrated the application of ‘travel’ in the context of self-extrication. Total travel is similar across self-extricating healthy volunteers with and without a collar. We suggest that where possible ‘travel’ is collected and reported in future biomechanical studies in this and related areas of research. It remains appropriate to apply a cervical collar to self-extricating casualties when the clinical target is that of movement minimisation.

Cervical collar use in spinal cord injury management

“…In healthy volunteers using cervical collars during vehicle and subsequent self‐extrication, collar use resulted in decreased maximal movement, a valuable surrogate measure for the risk of secondary SCI 31 . Maximal movements were found to be significantly decreased when a collar was used, while smaller movements still occurred resulting in comparable cumulative movement 31 . Although rescue services and medical providers operate with the rationale that smaller movements pose less risk for secondary spinal injury than larger movements, the effect of cumulative movement on SCI risk remains unknown.…”

“…31 Maximal movements were found to be significantly decreased when a collar was used, while smaller movements still occurred resulting in comparable cumulative movement. 31 Although rescue services and medical providers operate with the rationale that smaller movements pose less risk for secondary spinal injury than larger movements, the effect of cumulative movement on SCI risk remains unknown. Another study found that there was a significantly increased average movement of the cervical spine with cervical collar use during self-extrication than without.…”

Removal of the cervical collar from alpine rescue protocols? A biomechanical non-inferiority trial in real-life mountain conditions

“…This study reinforces emerging guidelines previously discussed supporting the removal of systematic cervical collars use from first-aid protocols to save critical time [ 7 , 9 – 11 , 30 , 52 , 53 ]. A recent study on maximum movement and cumulative movement of the head measured with IMUs during MVA self-extrications simulation showed that total travel motion is similar across self-extricating healthy volunteers with and without a collar [ 54 ].…”

A biomechanical study to compare spinal movement in a healthy volunteer during extrication between ‘chain cabling’ and ‘roof off’ methods of extrication

“…Maximum excursions (movement from a hypothetical midline) were calculated for anterior/posterior (AP) and lateral (LR) movement of the cervical and lumbar spine, respectively. In addition to reporting maximum excursions (the single largest movement) we report "travel" -the cumulative total of all movements throughout the extrication [18] .…”