Fatal atlanto-occipital dislocation secondary to airbag deployment

Survival rates in atlanto-occipital dissociation: a look at the past 20 years

BACKGROUND CONTEXT

Atlanto-occipital dissociation (AOD) has historically been considered a fatal injury. Recent small case series, however, have suggested that AOD injuries have become increasingly survivable. There has not been an adequately powered study that confirms this.

PURPOSE

The aim of this study is to assess whether the survival rate for patients with AOD increased over time.

STUDY DESIGN/SETTING

Retrospective case series.

PATIENT SAMPLE

Patients with traumatic AOD identified from our Level 1 Trauma Center database.

OUTCOME MEASURES

Mortality following traumatic AOD.

METHODS

Patients with traumatic AOD from 1996 to 2019 were retrospectively identified from our Level 1 Trauma Center database using International Classification of Diseases 9 and 10 codes. Patients were stratified into two cohorts- those diagnosed before August 1, 2015 and after.

RESULTS

A total of 52 patients met our inclusion criteria and were analyzed. Mean age was 34.41 (11.71), with 34 (65.4) females, and 26 (50) Hispanics. Mean BMI was 28.13 (7.30), mean injury severity score was 40.79 (21.72), and mean Glasgow coma scale was 5.91 (4.72). Overall, 33 patients died (63.5%). The mortality rate before 2015 was 81.80%, this number dropped down to 50% for those who were treated post 2015 (p=.01).

CONCLUSIONS

This study demonstrates that patients treated recently for AOD at a level 1 trauma center were more likely to survive than patients treated in the past at the same center. Possible reasons for the improved survival rate seen in this study include: increased awareness of AOD, improved diagnostic protocols with more uniform computed tomography based imaging, and advances in the care of these patients.

The association of occipitocervical dissociation and death as a result of blunt trauma

BACKGROUND CONTEXT

Despite multiple reports of survivability, dissociative occipitocervical injury (OCI) is generally accepted to be fatal in most cases. The actual number of trauma victims where OCI may have made the difference between life and death is unknown because multiple studies have shown that these injuries can be missed with current diagnostic methods. An improved understanding of the relative importance of OCI in blunt trauma mortality may help to refine protocols for the assessment and treatment of patients who arrive alive to the emergency room after severe blunt trauma. One way to improve our understanding is to document the relative frequency OCI relative to brain, liver, aorta, and spleen injuries in blunt trauma fatalities.

PURPOSE

In this study, we aimed to glean a more accurate estimate of the absolute and relative incidence of OCI after death from blunt trauma via a systematic review of data reported in the forensic literature.

STUDY DESIGN

Systematic literature review.

METHODS

A systematic literature search and review were undertaken. The search aimed to answer three primary questions: What is the true incidence of cervical spine injuries in blunt trauma fatalities? What is the incidence of dissociative OCIs specifically? and What is the incidence of these injuries relative to other common injuries associated with blunt trauma fatalities (central nervous system, spleen, liver, etc)? For that, two search protocols were used and included postmortem studies of blunt trauma mechanism in adult population.

RESULTS

The mean reported incidence of cervical spine injuries was 49.7% in blunt trauma fatalities. Dissociative OCIs were found to have a mean incidence of 18.1%. The relative frequencies of injuries were 49.7% for cervical spine, 41.8% for central nervous system, 20.8% for liver, 11.2% for spleen, and 10.8% for aorta.

CONCLUSIONS

In this systematic literature review, cervical spine injuries were found to be the most commonly reported finding associated with blunt trauma fatalities, occurring in nearly 50% of cases with occipitocervical dissociation accounting for nearly 20%. Older pathologic studies suggested a lesser overall and relative frequency and may have underestimated their incidence. Typically, these blunt cervical spine injuries were much more commonly found to disrupt the soft tissue stabilizing restraints (ligaments, facet capsules, etc) as opposed to causing bony fractures and, accordingly, were often not detected on plain radiographs. It is likely that the frequency of this injury is underestimated in patients surviving severe blunt trauma, placing them at risk for death from an occult source in the postinjury period. Additional research is needed to determine if improved methods to diagnose OCI and improved patient management protocols to protect against secondary injuries might reduce mortality in blunt trauma victims.

Atlanto-occipital dislocation: four case reports of survival in adults and review of the literature

Traumatic atlanto-occipital dislocation (AOD) is a rare cervical spine injury and in most cases fatal. Consequently, relatively few case reports of adult patients surviving this injury appeared in the literature. We retrospectively report four patients who survived AOD injury and were treated at our institution. A young man fell from height and a woman was injured in a traffic accident. Both patients survived the injury but died later in the hospital. The third patient had a motorcycle accident and survived with incomplete paraplegia. The last patient, a man involved in a working accident, survived without neurological deficit of the upper extremities. Rigid posterior fixation and complete reduction of the dislocation were applied in last two cases using Cervifix together with a cancellous bone grafting. Previously reported cases of patients surviving AOD are reviewed, and clinical features and operative stabilisation procedures are discussed.

Cervical spine injury and restraint system use in motor vehicle collisions

CONTEXT

Cervical spine injury related to motor vehicle collision (MVC) is a severe and often permanently disabling injury. Although advances in automobile crashworthiness have reduced both fatalities and some severe injuries, the impact of varying occupant restraint systems (seatbelts and airbags) on cervical spine injury is unknown.

OBJECTIVE

To investigate the relationship between the occurrence of cervical spine injury and occupant restraint systems among front seat occupants involved in frontal MVCs.

DESIGN, SETTING, AND PATIENTS

A case-control study among subjects obtained from the 1995 to 2001 National Automotive Sampling System (NASS). Cases were identified based on having sustained a cervical spine injury score of 2 or more on the Abbreviated Injury Scale, 1990 Revision.

RESULTS

Approximately half (44.7%) of 8,412 cases of cervical spine injury were unrestrained occupants while belted only, airbag only, and both restraint systems represented 38.2%, 8.8%, and 8.4% of cases, respectively. Overall, the combined use of airbag and seatbelt had the greatest protective effect, relative to unrestrained occupants, with an odds ratio (OR) of 0.19 and a 95% confidence interval (CI) of 0.12 to 0.30. Use of a seatbelt only also had a protective effect (OR: 0.40; 95% CI: 0.23-0.70). Occupant use of an airbag only neither increased nor decreased the risk of cervical spine injuries relative to unrestrained occupants (OR: 1.02; 95% CI: 0.57-2.13).

CONCLUSIONS

The results of this study suggest that there is an increase in overall protection against cervical spine injury by combining airbag and seatbelt restraint systems relative to seatbelt alone.

Pediatric cervical spine: normal anatomy, variants, and trauma

Emergency radiologic evaluation of the pediatric cervical spine can be challenging because of the confusing appearance of synchondroses, normal anatomic variants, and injuries that are unique to children. Cervical spine injuries in children are usually seen in the upper cervical region owing to the unique biomechanics and anatomy of the pediatric cervical spine. Knowledge of the normal embryologic development and anatomy of the cervical spine is important to avoid mistaking synchondroses for fractures in the setting of trauma. Familiarity with anatomic variants is also important for correct image interpretation. These variants include pseudosubluxation, absence of cervical lordosis, wedging of the C3 vertebra, widening of the predental space, prevertebral soft-tissue widening, intervertebral widening, and "pseudo-Jefferson fracture." In addition, familiarity with mechanisms of injury and appropriate imaging modalities will aid in the correct interpretation of radiologic images of the pediatric cervical spine.

Air bag injuries--a literature review in consideration of demands in forensic autopsies

Air bags have been implicated in saving lives and reducing morbidity associated with motor vehicle crashes since their introduction in the mid-1970s. However, there is increasing evidence showing that air bags can be a source of injury and even death in certain circumstances. As the number of air bag-equipped vehicles increases, air bag-related injuries have occurred more frequently. Thus, a greater awareness of air bag-related injuries is required in forensic autopsies. Here, we review thoroughly the literature concerning air bag-related injuries with special regard to their nature and causative mechanisms, and summarize air bag-related injuries observed in adults, children and infants.