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

Cervical misalignment in motorcyclists in relation to new helmet removal recommendations shown with augmented reality resources: A biomechanical analysis

Objective

The aim of this study is to determine the best technique and position for helmet removal in injured motorcyclists by comparing cervical misalignment produced in the supine position and prone position.

Method

Comparative cross-sectional clinical simulation study to quantify CM using biomechanical analysis with the use of inertial systems. The main variable was determined for the flexion-extension motion. The extraction was tested for both positions (prone position and supine position), which were repeated 3 times for each of the 30 volunteers included, and the movement from the initial neutral position was also determined, resulting in a total of 270 biomechanical studies.

Results

A flexion was observed when moving the patient from the neutral position to the SP, due to the size of the helmet, of 1.29° ± 5.12°. Helmet removal in the supine position resulted in an average flexion-extension range of 17.51° ± 6.49°, while the same extraction in prone position recorded an average range of 10.82° ± 8.05°. For the main variable, statistically significant differences were found when comparing prone position and supine position (p = 0.0087).

Conclusions

The main conclusion of the study is that the helmet removal should be done in the position in which we find the patient, whether in prone position or supine position. Additionally, the new technique described for the prone position causes less movement of the cervical spine than the usual supine position.

Wilderness Medical Society Clinical Practice Guidelines for Spinal Cord Protection: 2024 Update

The Wilderness Medical Society reconvened an expert panel to update best practice guidelines for spinal cord protection during trauma management. This panel, with membership updated in 2023, was charged with the development of evidence-based guidelines for management of the injured or potentially injured spine in wilderness environments. Recommendations are made regarding several parameters related to spinal cord protection. These recommendations are graded based on the quality of supporting evidence and balance the benefits and risks/burdens for each parameter according to American College of Chest Physicians methodology. Key recommendations include the concept that interventions should be goal-oriented (spinal cord/column protection in the context of overall patient and provider safety) rather than technique-oriented (immobilization). An evidence-based, goal-oriented approach excludes the immobilization of suspected spinal injuries via rigid collars or backboards.

Comparison of different techniques for prehospital cervical spine immobilization: Biomechanical measurements with a wireless motion capture system

BACKGROUND

Various rescue techniques are used for the prehospital transport of trauma patients. This study compares different techniques in terms of immobilization of the cervical spine and the rescue time.

METHODS

A wireless motion capture system (Xsens Technologies, Enschede, The Netherlands) was used to record motion in three-dimensional space and the rescue time in a standardized environment. Immobilization was performed by applying different techniques through different teams of trained paramedics and physicians. All tests were performed on the set course, starting with the test person lying on the floor and ending with the test person lying on an ambulance cot ready to be loaded into an ambulance. Six different settings for rescue techniques were examined: rescue sheet with/without rigid cervical collar (P1S1, P1S0), vacuum mattress and scoop stretcher with/without rigid cervical collar (P2S1, P2S0), and long spinal board with/without rigid cervical collar (P3S1, P3S0). Four time intervals were defined: the time interval in which the rigid cervical collar is applied (T0), the time interval in which the test person is positioned on rescue sheet, vacuum mattress and scoop stretcher, or long spinal board (T1), the time interval in which the test person is carried to the ambulance cot (T2), and the time interval in which the ambulance cot is rolled to the ambulance (T3). An ANOVA was performed to compare the different techniques.

RESULTS

During the simulated extrication procedures, a rigid cervical collar provided biomechanical stability at all angles with hardly any loss of time (mean angle ranges during T1: axial rotation P1S0 vs P1S1 p<0.0001, P2S0 vs P2S1 p<0.0001, P3S0 vs P3S1 p<0.0001; lateral bending P1S0 vs P1S1 p = 0.0263, P2S0 vs P2S1 p<0.0001, P3S0 vs P3S1 p<0.0001; flexion/extension P1S0 vs P1S1 p = 0.0023, P2S0 vs P2S1 p<0.0001). Of the three techniques examined, the scoop stretcher and vacuum mattress were best for reducing lateral bending in the frontal plane (mean angle ranges during T1: P2S1 vs P3S1 p = 0.0333; P2S0 vs P3S0 p = 0.0123) as well as flexion and extension in the sagittal plane (mean angle ranges during T2: P1S1 vs P2S1 p<0.0001; P1S0 vs P2S0 p<0.0001). On the other hand, the rescue sheet was clearly superior in terms of time (total duration P1S0 vs P2S0 p<0.001, P1S1 vs P2S1 p<0.001, P1S0 vs P3S0 p<0.001, P1S1 vs P3S1 p<0.001) but was always associated with significantly larger angular ranges of the cervical spine during the procedure. Therefore, the choice of technique depends on various factors such as the rescue time, the available personnel, as well as the severity of the suspected instability.

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

Background

Alpine skiing rescues are challenging because of the mountainous environment and risks of cervical spine motion (CSM) induced during victims’ extrications (EXs) and downhill evacuations (DEs). The benefits of applying a cervical collar (CC) over manual in-line stabilization without CC (MILS) in terms of spinal motion restriction during simulated alpine rescues are undocumented. Our hypothesis was that CSM recorded using MILS alone is non-inferior to CSM recorded with a CC according to a 10 degrees margin.

Methods

A total of 32 alpine extrications and 4 downhill evacuations on different slope conditions were performed using a high fidelity mannequin designed with a motion sensors instrumented cervical spine. The primary outcome was the peak extrication 3D excursion angle (Peak 3D θ_EX,) of the mannequin’s head. The secondary objectives were to describe the time to extrication completion (tEX) and to highlight which extrication manipulation is more likely to induce CSM.

Results

The median Peak 3D θ_EX recorded during flat terrain extrications using CC was 10.77° (95% CI 7.31°–16.45°) compared to 13.06° (95% CI 10.20°–30.36°) using MILS, and 16.09° (95% CI 9.07°–37.43°) for CC versus 16.65° (95% CI 13.80°–23.40°) using MILS on a steep slope. Peak 3D θ_EX with CC or using MILS during extrications were equivalent according to a 10 degrees non-inferiority hypothesis testing (p < 0.05). Time to extrication completion (tEX) was significantly reduced using MILS without CC on a flat terrain with a median duration of 237,3 s (95% CI 197.8 s, 272.2 s) compared to 358.7 s (95% CI 324.1 s, 472.4 s). During downhill evacuations, CSM with and without CC across all terrain conditions were negligible (< 5°). When CC is used; its installation manipulation induces the highest CSM. When EXs are done using MILS without CC, the logroll initiation is the manipulation inducing the highest risk of CSM.

Conclusion

For experienced ski patrollers, the biomechanical benefits of spinal motion restriction provided by CC over MILS during alpine skiing rescues appear to be marginal and CC use negatively affects rescue time.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13049-022-01031-3.

A Delphi study of rescue and clinical subject matter experts on the extrication of patients following a motor vehicle collision

BACKGROUND

Approximately 1.3 million people die each year globally as a direct result of motor vehicle collisions (MVCs). Following an MVC some patients will remain trapped in their vehicle; these patients have worse outcomes and may require extrication. Following new evidence, updated multidisciplinary guidance for extrication is needed.

METHODS

This Delphi study has been developed, conducted and reported to CREDES standards. A literature review identified areas of expertise and appropriate individuals were recruited to a Steering Group. The Steering Group formulated initial statements for consideration. Stakeholder organisations were invited to identify subject matter experts (SMEs) from a rescue and clinical background (total 60). SMEs participated over three rounds via an online platform. Consensus for agreement / disagreement was set at 70%. At each stage SMEs could offer feedback on, or modification to the statements considered which was reviewed and incorporated into new statements or new supporting information for the following rounds. Stakeholders agreed a set of principles based on the consensus statements on which future guidance should be based.

RESULTS

Sixty SMEs completed Round 1, 53 Round 2 (88%) and 49 Round 3 (82%). Consensus was reached on 91 statements (89 agree, 2 disagree) covering a broad range of domains related to: extrication terminology, extrication goals and approach, self-extrication, disentanglement, clinical care, immobilisation, patient-focused extrication, emergency services call and triage, and audit and research standards. Thirty-three statements did not reach consensus.

CONCLUSION

This study has demonstrated consensus across a large panel of multidisciplinary SMEs on many key areas of extrication and related practice that will provide a key foundation in the development of evidence-based guidance for this subject area.

Biomechanical Analysis of Cervical Motion With a Pediatric Immobilization and Extrication Device

OBJECTIVE

To determine the motions produced during pediatric extrication when using a system of motion estriction and extrication.

METHODS

Simulation-based biomechanical analysis study conducted with inertial sensors to measure motion produced in the cervical spine of a pediatric simulator during extrication from a vehicle.

RESULTS

The mean of the movements was 3.5° (SD ±1.35°). The mean time was 4 minutes 1 second (SD, ±45.09 seconds). The mean rotation toward the right was 3.34° (SD ±3.52°) and toward the left 2.62° (SD ±2.26°). The mean for lateralization was 6.24° (SD ±3.20°) toward the right and 2.50° (DE ±2.76°) toward the left. The mean for flexion was 2.36° (SD ±2.10°) and for extension 4.21° (SD ±2.15°).

CONCLUSIONS

The device analyzed allows for the extrication of the pediatric patient with high levels of motion restriction of the spinal column with the Pediatric Immobilization and Extrication System.

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

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.

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

Background

Motor 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.

Methods

Biomechanical 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.

Results

Data 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).

Conclusions

In 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.

Evaluation of external stabilization of type II odontoid fractures in geriatric patients-An experimental study on a newly developed cadaveric trauma model

Background

Along with the growing geriatric population, the number of odontoid fractures is steadily increasing. However, the effectiveness of immobilizing geriatric odontoid fractures using a cervical collar has been questioned. The aim of the present study is to analyze the physiological and pathological motion in odontoid fractures and to assess limitation of motion in the cervical spine when applying a cervical collar.

Methods

Motion analysis was performed with wireless motion tracker on unfixed geriatric human cadavers. First, a new geriatric type II odontoid fracture model was developed. In this model, the type II odontoid fracture is operated via a transoral approach. The physiological and pathological flexion and lateral bending of the cervical spine resulting from this procedure was measured. The resulting motion after external stabilization using a cervical collar was analyzed.

Results

The new geriatric type II odontoid fracture model was successfully established using seven unfixed human cadavers. The pathological flexion of the cervical spine was significantly increased compared to the physiological flexion (p = 0.027). Furthermore, the flexion was significantly reduced when a cervical collar was applied. In case of flexion the mean remaining motion was significantly reduced (p = 0.0017) from 41° to 14°. For lateral bending the mean remaining motion was significantly reduced (p = 0.0137) from 48° to 18°.

Conclusions

In case of type II odontoid fracture, flexion and lateral bending of the cervical spine are increased due to spinal instability. Thus, if an odontoid fracture is suspected in geriatric patients, the application of a cervical collar should always be considered since external stabilization can significantly reduce flexion and lateral bending.

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

The aim of this study was to compare the remaining motion of an immobilized cervical spine using an innovative cervical collar as well as two traditional cervical collars. The study was performed on eight fresh human cadavers. The cervical spine was immobilized with one innovative (Lubo Airway Collar) and two traditional cervical collars (Stifneck and Perfit ACE). The flexion and lateral bending of the cervical spine were measured using a wireless motion tracker (Xsens). With the Weinman Lubo Airway Collar attached, the mean remaining flexion was 20.0 ± 9.0°. The mean remaining flexion was lowest with the Laerdal Stifneck (13.1 ± 6.6°) or Ambu Perfit ACE (10.8 ± 5.8°) applied. Compared to that of the innovative Weinmann Lubo Airway Collar, the remaining cervical spine flexion was significantly decreased with the Ambu Perfit ACE. There was no significant difference in lateral bending between the three examined collars. The most effective immobilization of the cervical spine was achieved when traditional cervical collars were implemented. However, all tested cervical collars showed remaining motion of the cervical spine. Thus, alternative immobilization techniques should be considered.

Analysis of diagnostics, therapy and outcome of patients with traumatic atlanto-occipital dislocation

BACKGROUND CONTEXT

Patients' outcome following traumatic atlanto-occipital dislocation (AOD) has been poor. In recent years, an increasing number of patients surviving the initial trauma are admitted to hospital. In order to further improve the management of these patients, the knowledge of diagnostics and therapy as well as possible complications should be increased.

PURRPOSE

The aim of this study was to evaluate diagnostic parameters, therapy, early complications and outcome of patients with traumatic AOD.

STUDY DESIGN

Monocentric retrospective cohort study.

PATIENT SAMPLE

A total of 12 patients were included in this study.

OUTCOME MEASURES

The main outcome measure was functional patient outcome. Furthermore, radiographic and treatment data were analyzed.

METHODS

All patients suffering from traumatic AOD within an 8-year time period were included. Demographic data, radiological diagnostic parameters (condylar sum, basion dens interval, basion axis interval, power´s ratio, x-line method), as well as treatment data and complications of every patient were analyzed. Radiological parameters were compared with each other. Outcome was analyzed by a follow up examination.

RESULTS

The accident mechanisms were motor vehicle accidents (MVA), fall from high and low height. Basion dens interval, basion axis interval, power's ratio and x-line method were not reliable in identifying traumatic AOD (only up to 33% of the patients were identified). Twelve patients could be reviewed. Three patients were treated with surgery, five patients were treated nonsurgically. Four patients died before surgical therapy. All seven surviving patients (survival rate: 58.3%) were re-examined (mean follow-up time: 6.7 months). All patients had a GCS of 15. Three surviving patients suffered from persisting neurological deficits.

CONCLUSIONS

The most reliable way to diagnose AOD in Computer Topography is using the condylar sum. Surgical and nonsurgical measures can be employed with reasonable outcomes. Patient specific injury burden and clinical presentation should be taken into account when making treatment decisions for AOD.

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

Background

Motor vehicle collisions account for 1.3 million deaths and 50 million serious injuries worldwide each year. However, the majority of people involved in such incidents are uninjured or have injuries which do not prevent them exiting the vehicle. Self-extrication is the process by which a casualty is instructed to leave their vehicle and completes this with minimal or no assistance. Self-extrication may offer a number of patient and system-wide benefits. The efficacy of routine cervical collar application for this group is unclear and previous studies have demonstrated inconsistent results. It is unknown whether scripted instructions given to casualties on how to exit the vehicle would offer any additional utility.

The aim of this study was to evaluate the effect of cervical collars and instructions on spinal movements during self-extrication from a vehicle, using novel motion tracking technology.

Methods

Biomechanical data on extrications were collected using Inertial Measurement Units on 10 healthy volunteers. The different extrication types examined were: i) No instructions and no cervical collar, ii) No instructions, with cervical collar, iii) With instructions and no collar, and iv) With instructions and with collar. Measurements were recorded at the cervical and lumbar spine, and in the anteroposterior (AP) and lateral (LAT) planes. Total movement, mean, standard deviation and confidence intervals are reported for each extrication type.

Results

Data were recorded for 392 extrications. The smallest cervical spine movements were recorded when a collar was applied and no instructions were given: mean 6.9 mm AP and 4.4 mm LAT. This also produced the smallest movements at the lumbar spine with a mean of 122 mm AP and 72.5 mm LAT.

The largest overall movements were seen in the cervical spine AP when no instructions and no collar were used (28.3 mm). For cervical spine lateral movements, no collar but with instructions produced the greatest movement (18.5 mm). For the lumbar spine, the greatest movement was recorded when instructions were given and no collar was used (153.5 mm AP, 101.1 mm LAT).

Conclusions

Across all participants, the most frequently occurring extrication method associated with the least movement was no instructions, with a cervical collar in situ.

Cervical Spine Immobilization in Patients With a Geriatric Facial Structure: The Influence of a Geriatric Mandible Structure on the Immobilization Quality Using a Cervical Collar

INTRODUCTION

Demographic changes have resulted in an increase in injuries among geriatric patients. For these patients, a rigid cervical collar is crucial for immobilizing the cervical spine. However, evidence suggests that patients with a geriatric facial structure require a different means of immobilization than patients with an adult facial structure. This study aimed to analyze the remaining motion of the immobilized cervical spine based on facial structure.

MATERIALS AND METHODS

This study was performed on 8 fresh human cadavers. Facial structure was evaluated via ascertaining the mandibular angle by computer tomography. A mandibular angle below 130°, belongs to the adult facial structure group (n = 4) and a mandibular angle above 130°, belongs to the geriatric facial structure group (n = 4). The flexion and lateral bending of the immobilized cervical spine were analyzed in both groups using a wireless motion tracker system.

RESULTS

A flexion of up to 19.0° was measured in the adult facial structure group. The mean flexion in the adult vs. geriatric facial structure groups were 14.5° vs. 6.5° (ranges: 9.0-19.0 vs. 5.0-7.0°), respectively. Thus, cervical spine motion was (p = 0.0286) significantly more reduced in the adult facial structure group. No (p = 0.0571) significant difference was oberserved in the mean lateral bending of the adult facial structure group (14.5°) compared to the geriatric facial structure group (7.5°).

CONCLUSION

Emergency medical service personnel should therefore follow current guidelines and recommendations and perform cervical spine immobilization with a cervical collar, including in patients with a geriatric facial structure.

[The position of the head during treatment in the emergency room-an explorative analysis of immobilization of the cervical spine]

BACKGROUND

Immobilization of the cervical spine is a standard procedure in emergency medicine mostly achieved via a cervical collar. In the emergency room other forms of immobilization are utilized as cervical collars have certain drawbacks. The present study aimed to provide preliminary data on the efficiency of immobilization in the emergency room by analyzing the residual spinal motion of the patient's head on different kinds of head rests.

METHODS

In the present study biomechanical motion data of the cervical spine of a test subject were analyzed. The test subject was placed in a supine position on a mobile stretcher (Stryker M1 Roll-In System, Kalamazoo, MI, USA) wearing a cervical collar (Perfit ACE, Ballerup, Denmark). Three different head rests were tested: standard pillow, concave pillow and cavity pillow. The test subject carried out a predetermined motion protocol: right side inclination, left side inclination, flexion and extension. The residual spinal motion was recorded with wireless motion trackers (inertial measurement unit, Xsens Technologies, Enschede, The Netherlands). The first measurement was performed without a cervical collar or positioning on the pillows to measure the physiological baseline motion. Subsequently, three measurements were taken with the cervical collar applied and the pillows in place. From these measurements, a motion score was calculated that can represent the motion of the cervical spine.

RESULTS

When the test subject's head was positioned on a standard pillow the physiological motion score was reduced from 69 to 40. When the test subject's head was placed on concave pillow the motion score was further reduced from 69 to 35. When the test subject's head was placed on cavity pillow the motion score was reduced from 69 to 59. The observed differences in the overall motion score of the cervical spine are mainly due to reduced flexion and extension rather than rotation or lateral inclination.

CONCLUSION

The motion score of the cervical spine using motion sensors can provide important information for future analyses. The results of the present study suggest that trauma patients can be immobilized in the early trauma phase with a cervical collar and a head rest. The application of a cervical collar and the positioning on the concave pillow may achieve a good immobilization of the cervical spine in trauma patients in the early trauma phase.