Spinal Trauma

Subject-Specific Geometry of FE Lumbar Spine Models for the Replication of Fracture Locations Using Dynamic Drop Tests

For traumatic lumbar spine injuries, the mechanisms and influence of anthropometrical variation are not yet fully understood under dynamic loading. Our objective was to evaluate whether geometrically subject-specific explicit finite element (FE) lumbar spine models based on state-of-the-art clinical CT data combined with general material properties from the literature could replicate the experimental responses and the fracture locations via a dynamic drop tower-test setup. The experimental CT datasets from a dynamic drop tower-test setup were used to create anatomical details of four lumbar spine models (T12 to L5). The soft tissues from THUMS v4.1 were integrated by morphing. Each model was simulated with the corresponding loading and boundary conditions from the dynamic lumbar spine tests that produced differing injuries and injury locations. The simulations resulted in force, moment, and kinematic responses that effectively matched the experimental data. The pressure distribution within the models was used to compare the fracture occurrence and location. The spinal levels that sustained vertebral body fracture in the experiment showed higher simulation pressure values in the anterior elements than those in the levels that did not fracture in the reference experiments. Similarly, the spinal levels that sustained posterior element fracture in the experiments showed higher simulation pressure values in the vertebral posterior structures compared to those in the levels that did not sustain fracture. Our study showed that the incorporation of the spinal geometry and orientation could be used to replicate the fracture type and location under dynamic loading. Our results provided an understanding of the lumbar injury mechanisms and knowledge on the load thresholds that could be used for injury prediction with explicit FE lumbar spine models.

Emotional Interaction in Road Traffic Injury: A Qualitative Study On People With Spinal Cord Injury

The injury management in the acute phase of spinal cord injury starts at the accident scene and focuses on preventing and reducing secondary damages. The road traffic injured patients are mostly transferred by relatives, untrained laypeople, and the drivers of heavy vehicles. The current study explored the experience of people with spinal cord injury in the accident scene. This was a qualitative content analysis study using the semi-structured interviewing method with an interview guide for data collection. Purposive sampling method was performed within ten months until data saturation. We used the constant comparative approach recommended by Corbin and Strauss (2015). In total, 15 people with spinal cord injury and bystanders participated in this study. The central theme extracted in this study was "emotional interaction" that referred to the emotional reactions in managing road traffic victims. Two main categories of "emotional intervention" with "emotional atmosphere," "desperation," "rescue efforts," subcategories and "scene shock" with "unplanned intervention," "emotional behavior," "emotional decisions," and "emotional involvement," subcategories were classified. The emotional atmosphere of the scene and stress level of the victim and the relatives, and the insistence of the victim to escape from the harsh condition have caused those lacking medical knowledge and expertise to transfer the patient unsafely. This resulted in secondary damages, like aggravated spinal cord injury or even caused the spinal cord injury.

Mechanism of Injury and Clinical Variables in Thoracic Spine Fracture: A Case Control Study

Objective

To determine the mechanisms of injury and clinical findings significantly associated with traumatic thoracic spine (T-spine) fractures.

Methods

This was a case-control study in a tertiary adult trauma centre. Cases were patients admitted with traumatic T-spine fractures between January 1999 and August 2007, inclusive. Each case had two controls matched for gender, age and injury severity. Data were collected from patient medical records and the trauma service database. Factors potentially associated with T-spine fracture were derived from the literature, expert consensus and univariate analysis. Multivariate logistic regression was employed to determine factors significantly associated with T-spine fracture.

Results

Two hundred and sixty one cases and 512 controls were enrolled. Univariate analysis showed the mechanisms of fall from a height ≥2 meters (m) and motorbike accident ≥60 kilometers per hour were significantly associated with T-spine fracture (p<0.001). The clinical findings of thoracic back pain, tenderness, intoxication, step deformity and abnormal neurological symptoms were also significantly associated with T-spine fracture (p<0.05). Multivariate analysis indicated that falls from a height of ≥2 m and thoracic back pain were significantly and positively associated with T-spine fracture (p<0.001). However, intoxication was negatively associated with T-spine fracture.

Conclusions

Patients with T-spine injury are significantly more likely to have fallen from a height ≥2 m or to have had thoracic back pain but less likely to be intoxicated. These findings should be validated prospectively prior to development of clinical guidelines for the identification of patients who may benefit from CT screening of the thoracic spine.

Simulation of high energy vertebral fractures on complete porcine specimens

This work presents a novel method creating high energy vertebral fractures on complete swine specimens to investigate realistic vertebral fracture mechanisms. An apparatus was developed to maintain a porcine specimen in an upright position and apply a caudal impact simulating a fall. Five mature minipigs were impacted with varying impact magnitude. Computed tomography scans were used to assess the resulting fracture type, fracture level, spinal canal encroachment and fractures of adjacent bony structures. Lumbar fractures were produced on four specimens: three inferior endplate burst fractures (L2) and one superior endplate burst fracture (L5). One trial resulted in a hyperextension fracture between L2 and L3 vertebrae. Spinal canal encroachment was important for three specimens. No fracture was created on the pelvis or hind limbs. The proposed method developed and the resulting swine model of high energy vertebral fractures could be used to instigate novel biomechanical studies, to validate finite element models or to investigate surgical strategies.

Injuries significantly associated with thoracic spine fractures: a case-control study

OBJECTIVE

To determine injuries significantly associated with traumatic thoracic spine (T-spine) fractures

METHODS

This was a case-control study undertaken in an adult trauma centre. Cases were patients admitted with a traumatic T-spine fracture between January 1999 and August 2007. Each case had two controls matched for sex, age (+/-5 years) and injury severity classification (major/minor). Data were collected from patient medical records and the trauma service database. Multivariate logistic regression was used to determine injuries significantly associated with T-spine fracture.

RESULTS

Two hundred and sixty-one cases and 512 controls were enrolled. In both groups, mean age was 41 years and 70% of patients were male. Univariate analysis revealed a range of injuries that were significantly more common among the cases, especially cervical and lumbar spine injuries, sternal/scapular/clavicular/rib fractures, pneumo/haemothorax and pulmonary contusions (P < 0.01). Skull fractures and lower limb injuries were significantly more common among the controls (P < 0.01). Logistic regression analysis revealed that only cervical and lumbar spine injuries and rib fractures were positively associated with T-spine fracture (P < 0.001). Skull fractures and lower limb injuries were negatively associated with T-spine injury (P < 0.001).

CONCLUSION

Cervical and lumbar spine injuries and rib fractures are significantly associated with T-spine fracture. The presence of these injuries should raise suspicion of concomitant T-spine injury.