Cadaveric study of movement in the unstable upper cervical spine during emergency management: tracheal intubation and cervical spine immobilisation-a study protocol for a prospective randomised crossover trial

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.

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.

Development and first application testing of a new protocol for CT-based stability evaluation of the injured upper cervical spine

PURPOSE

For trauma surgeons, the evaluation of the stability of the upper cervical spine may be demanding. The aim of this study was to develop a protocol for decision-making on upper cervical spine stability in trauma patients based on established parameters obtained by CT imaging as well as testing the protocol by having it applied by trauma surgeons.

METHODS

A structured literature search on upper cervical spine stability was performed. The best evaluated instability criteria in CT imaging were determined. Based on these parameters a protocol for stability evaluation of the injured upper cervical spine was developed. A first application testing was performed. In addition to the assessment of instability, the time required for the assessment was analyzed.

RESULTS

A protocol for CT-based stability evaluation of the injured upper cervical spine based on the current literature was developed and displayed in a flow chart. Testing of the protocol found the stability of the cervical spine was correctly assessed in 55 of 56 evaluations (98.2%). In one test run, a stable upper cervical spine was judged to be unstable. Further analysis showed that this case was based on a measurement error. The assessment time of CT-images decreased significantly during repeat application of the protocol (p < 0.0001), from 336 ± 108 s (first case) to 180 ± 30 s (fourth case).

CONCLUSION

The protocol can be applied quickly and safely by non-specialized trauma surgeons. Thus, the protocol can support the decision-making process in CT-based evaluation of the stability of the injured upper cervical spine.

[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.

Success Rate of Endotracheal Intubation Using Inline Stabilization with and without Cervical Hard Collar; a Comparative Study

INTRODUCTION

Application of a rigid cervical collar may interfere with the laryngeal view, and potentially lead to failed endotracheal intubation (ETI). This study aimed to compare intubation success rates while performing inline stabilization with and without cervical hard collar.

METHODS

This randomized prospective comparative study included paramedics working in the Department of Emergency Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand to compare the success rates of endotracheal intubation on manikin using inline stabilization with and without cervical hard collar.

RESULTS

125 participants were evaluated; 63 in the rigid cervical collar and 62 in the non-cervical hard collar group. The rate of successful intubation was significantly higher using manual stabilization without cervical hard collar (61 (96.8%) vs. 55 (88.7%); p=0.048). The time required to successfully perform intubation was also shorter, with manual stabilization only (14.1 ±20.9 vs. 18.9±29.0; p = 0.081).

CONCLUSION

It seems that, removal of the rigid cervical collar during ETI in patients with suspected traumatic spine injury could increase the intubation success rate.

[Conventional intubation and laryngeal tube in cervical spine instability : Changes in the width of the dural sac in unfixed human body donors]

BACKGROUND

Airway management in patients with an unstable cervical spine requires a cautious approach if secondary damage is to be prevented but the question regarding the optimum method remains unresolved. The primary aim of the study was to investigate whether there were differences between intubation by conventional Macintosh laryngoscopy and placement of a laryngeal tube (LTS-D) with respect to dural sac compression on an unfixed human cadaver model with unstable injuries of the upper cervical spine. Secondary parameters that could be relevant in patients with unstable spinal injuries were also investigated.

MATERIAL AND METHODS

Orotracheal intubation by conventional direct laryngoscopy using a Macintosh blade and placement of a laryngeal tube (LTS-D) were performed in six fresh human cadavers. The dural sac was filled with contrast dye to allow continuous myelography by lateral fluoroscopy. Changes in the width of the dural sac at the cervical segments (C) C0/C1 and the C1/C2 levels as well as secondary parameters (angulation, distraction, intervention time) were assessed in the intact spine as well as in the presence of combined atlanto-occipital dislocation and atlanto-axial instability. The intubation methods were considered independent and examined using the Mann-Whitney U‑test.

RESULTS

At the C0/C1 level in the intact spine, conventional laryngoscopy caused less reduction of the width of the dural sac than placement of the LTS-D (0.33 mm vs. 0.46 mm, p = 0.035); however, in the presence of combined atlanto-occipital dislocation and atlanto-axial instability, placement of the LTS-D caused less reduction in the width of the dural sac than conventional intubation (1.18 mm vs. 0.68 mm, p = 0.005). At the C1/C2 level no differences were found with respect to changes in the width of the dural sac, neither in the intact spine nor in combined atlanto-occipital dislocation and atlanto-axial instability. Conventional intubation caused more angulation than placement of the LTS-D at both levels measured. Both methods did not cause distraction. The intervention times for placement of the laryngeal tube were shorter.

CONCLUSION

In an unfixed human cadaver model with combined atlanto-occipital dislocation and atlanto-axial instability, placement of the LTS-D caused less reduction in the width of the dural sac than conventional intubation at the level of the craniocervical junction. The LTS-D also caused less angulation and could be placed faster. It could therefore also be advantageous over conventional intubation in living patients with an unstable cervical spine.