An explorative, biomechanical analysis of spine motion during out-of-hospital extrication procedures

Abstract

Objectives: The extrication of patients following a road traffic collision is among the basic procedures in emergency medicine. Thus, extrication is a frequently performed procedure by most of the emergency medical services worldwide. The appropriate extrication procedure depends on the patient's current condition and accompanying injuries. A rapid extrication should be performed within a few minutes, and the cervical spine (at least) should be immobilized. To our knowledge, the scientific literature and current guidelines do not offer detailed recommendations on the extrication of injured patients. Thus, the aim of the current study is to compare the effectiveness of spinal stabilization during various out-of-hospital extrication procedures. Methods: This is an explorative, biomechanical analysis of spine motion during different extrication procedures on an example patient. Movement of the cervical spine was measured using a wireless human motion tracker. Movement of the thoracic and lumbar spine was quantified with 12 strain gauge sensors, which were positioned paravertebrally on both sites along the thoracic and lumbar spine. To interpret angular movement, a motionscore was developed based on newly defined axioms on the biomechanics of the injured spine. Results: Self-extrication showed the least spinal movement (overall motionscore sum = 667). Movement in the cervical spine could further be reduced by applying a cervical collar. The extrication by a rescue boa showed comparable results in overall spinal movement compared to the traditional extrication via spineboard (overall motionscore sum = 1862vs. 1743). Especially in the cervical spine, the spinal movement was reduced (motionscore sum = 339 vs. 595). However, the thoracic spine movement was increased (motionscore sum = 812 vs. 432). Conclusion: In case of a suspected cervical spine injury, guided self-extrication seems to be the best option. If the patient is not able to perform self-extrication, using a rescue boa might reduce cervical spinal movement compared to the traditional extrication procedure. Since promising results are shown in the case of extrication using a patient transfer sheet that has already been placed below the driver, future developments should focus on novel vehicle seats that already include an extrication device.

The role of cervical collars and verbal instructions in minimising spinal movement during self-extrication following a motor vehicle collision - a biomechanical study using healthy volunteers

“…Such a finding would also have significant implications for recommendations to bystander / buddy care at the scene of a motor vehicle collision. In our study there was a strong association between collar use and decreased cervical spinal movement (p < 0.001); this finding is in keeping with the intended purpose of such devices and is consistent with previous work [25,33]. It is contrary to the findings of Dixon et al who identified a small, mean increase in movement associated with collars when degrees of anterior-posterior, medial-lateral and rotational movement were combined [23].…”

“…Data from a total of 392 extrications were successfully collected for analysis (98% data capture success rate). Seven of the ten participants were female, with a mean age across all of the participants of 39 years (range 21-59) and BMI of 25.1 (range [19][20][21][22][23][24][25][26][27][28][29].…”

“…The finding of increased spinal movement with instructions was unexpected. Dixon et al utilised instructions for all of their self-extrications, which were also adopted for Haske's single participant study [23,25]. Engsberg et al did not provide instructions to their participants [33].…”

“…to allow facial packing in maxillofacial injury) [19][20][21][22]. These conflicting analyses suggest that the optimal role of cervical collars as an extrication device remains unclear, particularly in the setting of self-extrication [23][24][25].…”

Analysis of remaining motion using one innovative upper airway opening cervical collar and two traditional cervical collars

“…In the present study, the remaining flexion and the remaining lateral bending of the immobilized cervical spine were measured with a wireless human motion tracker system (Xsens Technologies, Enschede, Netherlands). Compared to other methods, this measurement method with a motion tracker has been proven 25 – 27 and guarantees exact measurement results 28 . The endpoints of the measurements were maximal flexion and maximal lateral bending.…”