Spinal movement and dural sac compression during airway management in a cadaveric model with atlanto-occipital instability

Airway management in patients with suspected or confirmed cervical spine injury: Guidelines from the Difficult Airway Society (DAS), Association of Anaesthetists (AoA), British Society of Orthopaedic Anaesthetists (BSOA), Intensive Care Society (ICS), Neuro Anaesthesia and Critical Care Society (NACCS), Faculty of Prehospital Care and Royal College of Emergency Medicine (RCEM)

BACKGROUND

There are concerns that airway management in patients with suspected or confirmed cervical spine injury may exacerbate an existing neurological deficit, cause a new spinal cord injury or be hazardous due to precautions to avoid neurological injury. However, there are no evidence-based guidelines for practicing clinicians to support safe and effective airway management in this setting.

METHODS

An expert multidisciplinary, multi-society working party conducted a systematic review of contemporary literature (January 2012-June 2022), followed by a three-round Delphi process to produce guidelines to improve airway management for patients with suspected or confirmed cervical spine injury.

RESULTS

We included 67 articles in the systematic review, and successfully agreed 23 recommendations. Evidence supporting recommendations was generally modest, and only one moderate and two strong recommendations were made. Overall, recommendations highlight key principles and techniques for pre-oxygenation and facemask ventilation; supraglottic airway device use; tracheal intubation; adjuncts during tracheal intubation; cricoid force and external laryngeal manipulation; emergency front-of-neck airway access; awake tracheal intubation; and cervical spine immobilisation. We also signpost to recommendations on pre-hospital care, military settings and principles in human factors.

CONCLUSIONS

It is hoped that the pragmatic approach to airway management made within these guidelines will improve the safety and efficacy of airway management in adult patients with suspected or confirmed cervical spine injury.

Dynamic in vivo 3D atlantooccipital kinematics during multiplanar physiologic motions

Normal biomechanics of the upper cervical spine, particularly at the atlantooccipital joint, remain poorly characterized. The purpose of this study was to determine the intervertebral kinematics of the atlantooccipital joint (occiput-C1) during three-dimensional in vivo physiologic movements. Twenty healthy young adults performed dynamic flexion/extension, axial rotation, and lateral bending while biplane radiographs were collected at 30 images per second. Motion at occiput-C1 was tracked using a validated volumetric model-based tracking process that matched subject-specific CT-based bone models to the radiographs. The occiput-C1 total range of motion (ROM) and helical axis of motion (HAM) was calculated for each movement. During flexion/extension, the occiput-C1 moved almost exclusively in-plane (ROM: 17.9 ± 6.9°) with high variability in kinematic waveforms (6.3°) compared to the in-plane variability during axial rotation (1.4°) and lateral bending (0.9°) movements. During axial rotation, there was small in-plane motion (ROM: 4.2 ± 2.5°) compared to out-of-plane flexion/extension (ROM: 12.7 ± 5.4°). During lateral bending, motion occurred in-plane (ROM: 9.0 ± 3.1°) and in the plane of flexion/extension (ROM: 7.3 ± 2.7°). The average occiput-C1 axis of rotation intersected the sagittal and coronal planes 7 mm to 18 mm superior to the occipital condyles. The occiput-C1 axis of rotation pointed 60° from the sagittal plane during axial rotation but only 10° from the sagittal plane during head lateral bending. These novel results are foundational for future work on upper cervical spine kinematics.

Airway management in patients with suspected or confirmed traumatic spinal cord injury: a narrative review of current evidence

Around 1 million people sustain a spinal cord injury each year, which can have significant psychosocial, physical and socio‐economic consequences for patients, their families and society. The aim of this review is to provide clinicians with a summary of recent studies of direct relevance to the airway management of patients with confirmed or suspected traumatic spinal cord injury to promote best clinical practice. All airway interventions are associated with some degree of movement of the cervical spine; in general, these are very small and whether these are clinically significant in terms of impingement of the spinal cord is unclear. Manual in‐line stabilisation does not effectively immobilise the cervical spine and increases the likelihood of difficult and failed tracheal intubation. There is no clear evidence of benefit of awake tracheal intubation techniques in terms of prevention of secondary spinal cord injury. Videolaryngoscopy appears to cause a similar degree of cervical spine displacement as flexible bronchoscope‐guided tracheal intubation and is an appropriate alternative approach. Direct laryngoscopy does cause a slightly greater degree of cervical spinal movement during tracheal intubation than videolaryngoscopy, but this does not appear to increase the risk of spinal cord compression. The risk of spinal cord injury during tracheal intubation appears to be minimal even in the presence of gross cervical spine instability. Depending on the clinical situation, practitioners should choose the tracheal intubation technique with which they are most proficient and that is most likely to minimise cervical spine movement.

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.

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 Influence of Cervical Spine Angulation on Symptoms Associated With Wearing a Rigid Neck Collar

Introduction:

Rigid cervical spine collars can be used to maintain the position of the cervical spine following injury or surgery. However, they have been associated with difficulty swallowing, pressure sores and pain, particularly in older patients. We aimed to investigate the relationship between cervical spine angulation, a rigid neck collar and neck pain in healthy young and older adults.

Methods:

Twenty healthy young adults aged 25 ± 3 years and 17 healthy older adults aged 80 ± 8 years were tested. Magnetic resonance imaging scans of their cervical spines were taken before and after the rigid neck collar was worn for 1 hour. Measurement of vertebral angulation involved digitization of the scans and joint angle calculations using image processing software. Pain was quantified before and after the collar was worn, using a visual analogue scale.

Results:

Pain scores increased in the young group after the collar was worn (p = 0.001). The older group showed no difference in pain score after the collar was worn. Statistical tests showed no significant correlations between the change in cervical angles and the change in pain scores after the collar was worn.

Discussion:

The aging process may contribute to the changing distribution of subcutaneous tissue and increase risk of symptoms associated with wearing a collar. Oesophageal compression is not a result of collar use.

Conclusion:

There is no correlation between cervical spine vertebrae angulation and symptoms associated with wearing a neck collar. Generally, older individuals have greater cervical lordosis angles, and more straight and lordotic neck shapes. Older individuals may be more prone to skin-interface pressures from the neck collar than younger individuals.

[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.

Remaining Cervical Spine Movement Under Different Immobilization Techniques

BACKGROUND

Immobilization of the cervical spine by Emergency Medical Services (EMS) personnel is a standard procedure. In most EMS, multiple immobilization tools are available.The aim of this study is the analysis of residual spine motion under different types of cervical spine immobilization.

METHODS

In this explorative biomechanical study, different immobilization techniques were performed on three healthy subjects. The test subjects' heads were then passively moved to cause standardized spinal motion. The primary endpoints were the remaining range of motion for flexion, extension, bending, and rotation measured with a wireless human motion detector.

RESULTS

In the case of immobilization of the test person (TP) on a straight (0°) vacuum mattress, the remaining rotation of the cervical spine could be reduced from 7° to 3° by additional headblocks. Also, the remaining flexion and extension were reduced from 14° to 3° and from 15° to 6°, respectively. The subjects' immobilization was best on a spine board using a headlock system and the Spider Strap belt system (MIH-Medical; Georgsmarienhütte, Germany). However, the remaining cervical spine extension increased from 1° to 9° if a Speedclip belt system was used (Laerdal; Stavanger, Norway). The additional use of a cervical collar was not advantageous in reducing cervical spine movement with a spine board or vacuum mattress.

CONCLUSIONS

The remaining movement of the cervical spine is minimal when the patient is immobilized on a spine board with a headlock system and a Spider Strap harness system or on a vacuum mattress with additional headblocks. The remaining movement of the cervical spine could not be reduced by the additional use of a cervical collar.

French recommendations for the management of patients with spinal cord injury or at risk of spinal cord injury

OBJECTIVES

To update the French guidelines on the management of trauma patients with spinal cord injury or suspected spinal cord injury.

DESIGN

A consensus committee of 27 experts was formed. A formal conflict-of-interest (COI) policy was developed at the outset of the process and enforced throughout. The entire guidelines process was conducted independently of any industrial funding (i.e. pharmaceutical, medical devices). The authors were advised to follow the rules of the Grading of Recommendations Assessment, Development and Evaluation (GRADE®) system to guide assessment of quality of evidence. The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasised.

METHODS

The committee studied twelve questions: (1) What are the indications and arrangements for spinal immobilisation? (2) What are the arrangements for pre-hospital orotracheal intubation? (3) What are the objectives of haemodynamic resuscitation during the lesion assessment, and during the first few days in hospital? (4) What is the best way to manage these patients to improve their long-term prognosis? (5) What is the place of corticosteroid therapy in the initial phase? (6) What are the indications for magnetic resonance imaging in the lesion assessment phase? (7) What is the optimal time for surgical management? (8) What are the best arrangements for orotracheal intubation in the hospital environment? (9) What are the specific conditions for weaning these patients from mechanical ventilation for? (10) What are the procedures for analgesic treatment of these patients? (11) What are the specific arrangements for installing and mobilising these patients? (12) What is the place of early intermittent bladder sampling in these patients? Each question was formulated in a PICO (Patients, Intervention, Comparison, Outcome) format and the evidence profiles were produced. The literature review and recommendations were made according to the GRADE® Methodology.

RESULTS

The experts' work synthesis and the application of the GRADE method resulted in 19 recommendations. Among the recommendations formalised, 2 have a high level of evidence (GRADE 1+/-) and 12 have a low level of evidence (GRADE 2+/-). For 5 recommendations, the GRADE method could not be applied, resulting in expert advice. After two rounds of scoring and one amendment, strong agreement was reached on all the recommendations.

CONCLUSIONS

There was significant agreement among experts on strong recommendations to improve practices for the management of patients with spinal cord injury.

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

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.

[Development and first application testing of a new protocol for preclinical spinal immobilization in children : Assessment of indications based on the E.M.S. IMMO Protocol Pediatric]

BACKGROUND

To protect the spine from secondary damage, spinal immobilization is a standard procedure in prehospital trauma management. Immobilization protocols aim to support emergency medicine personnel in quick decision making but predominantly focus on the adult spine; however, trauma mechanisms and injury patterns in adults differ from those in children and applying adult prehospital immobilization protocols to pediatric patients may be insufficient. Adequate protocols for children with spinal injuries are currently unavailable.

OBJECTIVE

The aim of this study was (i) to develop a protocol that supports decision making for prehospital spinal immobilization in pediatric trauma patients based on evidence from current scientific literature and (ii) to perform a first analysis of the quality of results if the protocol is used by emergency personnel.

MATERIAL AND METHODS

Based on a structured literature search a new immobilization protocol was developed. Analysis of the quality of results was performed by a questionnaire containing four case scenarios in order to assess correct decision making. The decision about spinal immobilization was made without and with the utilization of the protocol.

RESULTS

The E.M.S. IMMO Protocol Pediatric was developed based on the literature. The analysis of the quality of results was performed involving 39 emergency medicine providers. It could be shown that if the E.M.S. IMMO Protocol Pediatric was used, the correct type of immobilization was chosen more frequently. A total of 38 out of 39 participants evaluated the protocol as helpful.

CONCLUSION

The E.M.S. IMMO Protocol Pediatric provides decision-making support whether pediatric spine immobilization is indicated with respect to the cardiopulmonary status of the patient. In a first analysis, the E.M.S. IMMO Protocol Pediatric improves decision making by emergency medical care providers.

Spinal Immobilization in the Trauma Room - a Survey-Based Analysis at German Level I Trauma Centers

BACKGROUND

Spinal immobilization is a standard procedure in daily out-of-hospital emergency care. Homogenous recommendations concerning the immobilization of trauma patients during the first therapy in the emergency department do not exist. The aim of the current study was the analysis of the existing strategies concerning spinal immobilization in German level I trauma centers by an internet-based survey.

MATERIALS AND METHODS

The current study is a survey-based analysis of the current strategies concerning spinal immobilization in all 107 level I trauma centers in Germany. The internet-based survey consists of 6 items asking about immobilization in the emergency department.

RESULTS

The return rate was 47.7%. In 14 (28.6%) level I trauma centers the patients remained immobilized on the immobilization tool used by the professional emergency care providers. In 19 (38.8%) level I trauma centers the patients were transferred to a stretcher with a soft positioning mattress on it. Patient transfer to a spineboard or to a TraumaMattress was performed in 11 (22.4%) and 7 (14.3%) level I trauma centers, respectively. Trauma patients were never transferred to a vacuum mattress. Cervical spine protection was most of the time performed by a cervical collar (n = 48; 98.0%). In general, the survey's participants were mainly satisfied (mean = 84/100) with the current strategy of spinal immobilization. The satisfaction was best if the spineboard is used.

DISCUSSION

Patient positioning during initial emergency therapy in the emergency department of German level I trauma centers is highly heterogenous. Besides complete full body immobilization, also the lack of any immobilization was reported by the survey's participants.

Cervical instability in patients with Trisomy 21: The eternal gamble

Patients with Trisomy 21 are particularly at risk of cervical instability due to ligamentous laxity and osseous abnormalities. Up to 30% of Trisomy 21 patients are affected by atlanto-axial or atlanto-occipital instability, but only 1%-2% of cases are symptomatic. The radiologic assessment of cervical instability is not unanimously considered mandatory. The dynamic cervical spine radiograph is the most common screening tool for ruling out cervical spine instability in patients with Trisomy 21, and it is often requested before surgery. Several measurements have been investigated to assess the presence and degree of cervical instability; however, no conclusive recommendations have been forthcoming. In daily practice, many anesthesiologists may provide anesthesia via such means as laryngoscopy and tracheal intubation during surgery, without any radiological investigations before surgery. This review focuses on the diagnostic and prognostic measures available to evaluate the presence and degree of cervical instability in patients with Trisomy 21 and to propose practical recommendations to be applied in clinical practice.