Independent predictors of survival after traumatic atlanto-occipital dissociation

Atlanto-occipital Dissociation: A Review on Epidemiology, Recognition and Diagnosis, Management Options, Outcomes, and Future Directions

Atlanto-occipital dissociation (AOD) is an extremely common injury but often fatal. In a systematic review from 2010, AODs were present in almost 20% of blunt trauma fatalities. It is an injury many patients do not survive; therefore, few are treated, even at high volume trauma centers. In survivors, his injury is often missed or the diagnosis is often delayed. Mortality rates commonly reach beyond 60% when injury patterns go unrecognized. Approximately 50% of patients with AOD sustain blunt cerebrovascular injury and nearly 20% of patients present with traumatic brain injury (TBI) or stroke. This pathology was once considered uniformly fatal. However, over the last 20 years, significant advancements have been made both clinically and radiographically, to better identify and manage this injury pattern. Despite improvements in clinical comprehension and improved time to diagnosis, less than 75% of cases are currently recognized within 24 hours. Less than 40% of patients who suffer AOD are independent with functionality, without neurological impairment. This article reviews current literature regarding AOD in hopes to improve timing to diagnosis, subsequent prognosis, timing to fixation or stabilization, and postoperative recovery.

Traumatic atlanto-occipital dislocation with successfully bystander resuscitation after cardiopulmonary arrest: A case report

This case report describes successful bystander cardiopulmonary resuscitation after a cardiopulmonary arrest due to a traffic accident, followed by early diagnosis and treatment of a traumatic atlanto-occipital dislocation, resulting in successful community reintegration.

Management of Traumatic Atlantooccipital Dissociation at a Level 1 Trauma Center: A Retrospective Case Series

OBJECTIVE

Atlantooccipital dislocation (AOD) is a highly unstable and often neurologically devastating injury to the craniocervical junction that typically results from high-energy trauma. Management of these devastating injuries is complex, with prognostication difficult due to high rates of concomitant intracranial and systemic injuries. This report highlights advances in management of AOD and appropriate implementation of operative adjuncts including neuronavigation and the use of intraoperative neuromonitoring.

METHODS

All patients with AOD presenting to a high-volume, level 1 trauma center between January 2015 and August 2021 were retrospectively identified through a prospectively maintained database of patients presenting with traumatic spine injuries. Medical records, including imaging reports, clinical documentation, and intraoperative neurophysiological reports were reviewed.

RESULTS

A total of 11 patients were identified with patterns of injury consistent with AOD. Fifty-five percent of patients survived until discharge. 73% of patients underwent surgery for stabilization. All 4 patients with preoperative neurologic deficits who underwent surgery had monitorable transcranial motor evoked potentials and somatosensory evoked potentials. Two experienced significant motor recovery postoperatively, and 2 did not survive to discharge. Blunt cerebrovascular injuries were identified in 73% of patients.

CONCLUSION

AOD is encountered with increasing frequency. The identification and management of this specific injury is complicated by the volume and severity of associated injuries, especially concomitant traumatic brain injury. Timely recognition is critical and the use of surgical adjuncts including intraoperative neurophysiologic monitoring and surgical navigation can increase the safety and success of these procedures while also providing prognostic information on potential for motor recovery.

Atlanto-occipital dislocation with concomitant severe traumatic brain injury: A retrospective study at a level 1 trauma center

BACKGROUND

Traumatic atlanto-occipital dislocation (AOD) is a life-threatening injury. Although traumatic brain injury (TBI) is associated with increased mortality in AOD patients, a detailed individual analysis of these patients is lacking in the literature.

METHODS

Patients ≥16 years old who were diagnosed of AOD with concomitant severe TBI from 2010 to 2020 were included in this retrospective study. We examined the epidemiology, injury mechanisms, associated injuries, and outcomes of these patients.

RESULTS

Eight patients were included. Six patients died before any intervention could be performed, and two patients underwent an occipito-cervical fixation, showing a notorious neurologic improvement on follow-up. Cardiorespiratory arrest (CRA) was a strong predictor of subsequent death. CT signs of diffuse axonal injury (DAI) were present in most patients and were confirmed by magnetic resonance imaging (MRI) in survivors. Although TBI was not the main cause of death, it was responsible for the delayed neurological improvement and deferred stabilization. The average sensitivity of the different used methodologies for AOD diagnosis ranged from 0.50 to 1.00, being the Basion Dens Interval (BDI) and the Condyle-C1 interval (CCI) sum the most reliable criteria. Non-survivors tended to show greater distraction measurements. The high incidence of condylar avulsion fractures suggests that their visualization on the initial CT study should heighten the suspicion for AOD.

CONCLUSIONS

Our data suggest that patients with AOD and concomitant severe TBI might be salvageable patients. In those who survive beyond the first hospital days and show neurological improvement, surgical treatment should be performed as they can achieve an important neurologic recovery.

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.

Upper Cervical Trauma

Craniocervical injuries (CCJs) account for 10% to 30% of all cervical spine trauma. An increasing number of patients are surviving these injuries due to advancements in automobile technology, resuscitation techniques, and diagnostic modalities. The leading injury mechanisms are motor vehicle crashes, falls from height, and sports-related events. Current treatment with urgent rigid posterior fixation of the occiput to the cervical spine has resulted in a substantial reduction in management delays expedites treatment of CCJ injuries. Within CCJ injuries, there is a spectrum of instability, ranging from isolated nondisplaced occipital condyle fractures treated nonoperatively to highly unstable injuries with severely distracted craniocervical dissociation. Despite the evolution of understanding and improvement in the management of cases regarding catastrophic failure to diagnose, subsequent neurologic deterioration still occurs even in experienced trauma centers. The purpose of this article is to review the injuries that occur at the CCJ with the accompanying anatomy, presentation, imaging, classification, management, and outcomes.

Occipitocervical fusion of traumatic atlanto-occipital dissociation in a patient with autofused cervical facet joints: illustrative case

BACKGROUND

Patients who survive traumatic atlanto-occipital dissociation (AOD) may present with normal neurological examinations and near-normal-appearing diagnostic images, such as cervical radiographs and computed tomography (CT) scans.

OBSERVATIONS

The authors described a neurologically intact 64-year-old female patient with a degenerative autofusion of her right C4–5 facet joints who presented to their center after a motor vehicle collision. Prevertebral soft tissue swelling and craniocervical subarachnoid hemorrhage prompted awareness and consideration for traumatic AOD. An abnormal occipital condyle–C1 interval (4.67 mm) on CT and craniocervical junction ligamentous injury on magnetic resonance imaging (MRI) confirmed the diagnosis of AOD. Her autofused right C4–5 facet joints were incorporated into the occipitocervical fusion construct.

LESSONS

Traumatic AOD can be easily overlooked in patients with a normal neurological examination and no associated upper cervical spine fractures. A high index of suspicion is needed when evaluating CT scans because normal values for craniocervical parameters are significantly different from the accepted ranges of normal on radiographs in the adult population. MRI of the cervical spine is helpful to evaluate for atlanto-occipital ligamentous injury and confirm the diagnosis. Occipitocervical fusion construct may need to be extended to incorporate spinal levels with degenerative autofusion to prevent adjacent level degeneration.

Radiologic predictors of in-hospital mortality after traumatic craniocervical dissociation

BACKGROUND

Traumatic craniocervical dissociation (CCD) is the forcible dislocation of the skull from the vertebral column. Because most CCD patients die on scene, prognostication for those who arrive alive to hospital is challenging. The study objective was to determine if greater dissociation, based on radiologic measurements of CCD, is predictive of in-hospital mortality among patients surviving to the emergency department.

METHODS

All trauma patients arriving to our Level 1 trauma center (January 2008 to April 2019) with CCD were retrospectively identified and included. Transfers and patients without computed tomography head/cervical spine were excluded. Study patients were dichotomized into groups based on in-hospital mortality. Radiologic measurements of degree of CCD were performed based on the index computed tomography scan by an attending radiologist with Emergency Radiology fellowship training. Measurements were compared between patients who died in-hospital versus those who survived.

RESULTS

After exclusions, 36 patients remained: 12 (33%) died and 24 (67%) survived. Median age was 55 years (30-67 years) versus 44 (20-61 years) (p = 0.199). Patients who died had higher Injury Severity Score (39 [31-71] vs. 27 [14-34], p = 0.019) and Abbreviated Injury Scale head/neck score (5 [5-5] vs. 4 [3-4], p = 0.001) than survivors. The only radiologic measurement that differed between groups was greater soft tissue edema at mid C1 among patients who died (12.37 [7.60-14.95] vs. 7.86 [5.25-11.61], p = 0.013). Receiver operating characteristic curve analysis of soft tissue edema at mid C1 and mortality revealed 10.86 mm or greater of soft tissue width predicted mortality with sensitivity and specificity of 0.75. All other radiologic parameters, including the basion-dens interval, were comparable between groups (p > 0.05).

CONCLUSION

Among patients who arrive alive to hospital after traumatic CCD, greater radiologic dissociation is not associated with increased mortality. However, increased soft tissue edema at the level of mid C1, particularly 10.86 mm or greater, is associated with in-hospital death. These findings improve our understanding of this highly lethal injury and impart the ability to better prognosticate for patients arriving alive to hospital with CCD.

LEVEL OF EVIDENCE

Prognostic and Epidemiological, Level III.

Successful non-operative management for atlanto-occipital dislocation resulting in spinal cord contusion in a patient with atlanto-occipital assimilation and severe Chiari I malformation

Background:

Atlanto-occipital dislocation (AOD) is a rare, highly morbid, and highly lethal injury that results from high-energy trauma and almost universally requires operative management for satisfactory outcomes. It can be difficult to identify the severity of injury at the time of presentation, and when diagnosis is delayed outcomes worsen significantly. Anatomic anomalies of the craniovertebral junction may further complicate its detection. When such anomalies are present either singly or in combination, they are known to cause space constraints which may increase the likelihood of spinal cord injury. Given that such anomalies and AOD are rare, few examples of patients with both are reported in the literature. Furthermore, it is not clear in what way patient management may be impacted in this context.

Case Description:

We will present a unique case of an 18-year-old patient with traumatic AOD and an intact neurologic examination who was found to have atlanto-occipital assimilation (AOA), platybasia, basilar invagination, and severe Chiari I malformation, who was treated effectively with non-operative management.

Conclusion:

Our case demonstrates the successful application of a non-operative treatment strategy in a carefully selected patient with AOD in the context of AOA.