Assessing spinal movement during four extrication methods: a biomechanical study using healthy volunteers

Tim Nutbeam,Jason E Smith,Jono Bowdler,James Shippen,Lee Wallis,Barbara May,Willem Stassen,Rob Fenwick

doi:10.1186/s13049-022-00996-5

Abstract

BackgroundMotor vehicle collisions are a common cause of death and serious injury. Many casualties will remain in their vehicle following a collision. Trapped patients have more injuries and are more likely to die than their untrapped counterparts. Current extrication methods are time consuming and have a focus on movement minimisation and mitigation. The optimal extrication strategy and the effect this extrication method has on spinal movement is unknown. The aim of this study was to evaluate the movement at the cervical and lumbar spine for four commonly utilised extrication techniques.MethodsBiomechanical data was collected using inertial Measurement Units on 6 healthy volunteers. The extrication types examined were: roof removal, b-post rip, rapid removal and self-extrication. Measurements were recorded at the cervical and lumbar spine, and in the anteroposterior (AP) and lateral (LAT) planes. Total movement (travel), maximal movement, mean, standard deviation and confidence intervals are reported for each extrication type.ResultsData from a total of 230 extrications were collected for analysis. The smallest maximal and total movement (travel) were seen when the volunteer self-extricated (AP max = 2.6 mm, travel 4.9 mm). The largest maximal movement and travel were seen in rapid extrication extricated (AP max = 6.21 mm, travel 20.51 mm).The differences between self-extrication and all other methods were significant (p < 0.001), small non-significant differences existed between roof removal, b-post rip and rapid removal.Self-extrication was significantly quicker than the other extrication methods (mean 6.4 s).ConclusionsIn healthy volunteers, self-extrication is associated with the smallest spinal movement and the fastest time to complete extrication. Rapid, B-post rip and roof off extrication types are all associated with similar movements and time to extrication in prepared vehicles.

Highlights

Motor vehicle collisions are a common cause of death and serious injury
In healthy volunteers, self-extrication is associated with the smallest spinal movement and the fastest time to complete extrication
Rescue service teaching recommends that casualties in the assisted or medical groups receive a traditional extrication method, as it is understood that these result in less spinal movement than other techniques [11]

Summary

Introduction

Motor vehicle collisions are a common cause of death and serious injury. Many casualties will remain in their vehicle following a collision. (assisted extrication) (iii) the casualty is either advised or chooses not to self-extricate due to concern of exacerbating injury ( spinal injury) by movement (medically trapped), (iv) the casualty is physically trapped in the vehicle (e.g. due to displaced road furniture) or requires disentanglement from the vehicle wreckage by rescue services (disentanglement and rescue) [9] These groups are not mutually exclusive and a patient may belong in more than one group across their extrication experience. Rescue service teaching recommends that casualties in the assisted or medical groups receive a traditional extrication method, as it is understood that these result in less spinal movement than other techniques [11] These principles have been challenged; with a number of small biomechanical studies demonstrating that selfextrication may cause less movement than more traditional extrication techniques [12,13,14]

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