The pathological anatomy of fatal atlanto-occipital dislocations

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 spine instability systematic review: a bibliometric analysis of the 100 most influential publications

BACKGROUND

Instability in the upper cervical spine, although rare, can be devastating. This spectrum of conditions includes occipitocervical instability, atlantoaxial instability and atlantoaxial rotatory displacement. Knowledge of the literature can provide better understanding of disease processes and management, and aid in clinical decision making. The objective of this study was to perform a bibliometric analysis to formulate a comprehensive review of the most cited publications.

METHODS

A systematic search of the literature was conducted using the Clarivate Web of Science database. The search query was '"Atlanto-occipital dislocation" OR "atlanto-occipital dissociation" OR "atlantoaxial rotatory displacement" OR "atlantoaxial instability"'. The top 100 articles based on frequency of citation were included in our study. Data extracted from articles included frequency of citation, year of publication, country of origin, journal of publication, level of evidence and article type.

RESULTS

Our initial search yielded 257 results that met the criteria. Articles not pertaining to atlanto-occipital instability were removed. Citation frequency ranged from 15 to 195. The most cited article was "Traumatic Anterior Atlanto-Occipital Dislocation" published by Powers et al. in 1979. The most productive decade was 2000-2009 with 45 publications. All decades showed a progressive increase in the number of papers published except for 2010-2019. Overall, 19 countries contributed and the most productive was the United States (n=61). The articles found in our search were cited a total of 4,095 times (3,463 without self-citations) averaging 40.95 citations per publication.

DISCUSSION

The goal of a bibliometric study is to assess trends in a specific field of study, provide evidence for the impact of an individual or field of study's research, and highlight potential areas for future research. While the number of citations does not necessarily reflect publication quality, it reflects overall influence based on recognition by peers in the field. Publications from the last 20 years have emphasized the use of newer technologies such as computed tomography (CT) and magnetic resonance imaging (MRI) to aid in diagnosis. Our study highlights the lack of high-level evidence articles and underscores that our understanding of these conditions in both pediatric and adult patients is maturing.

Clinical and Radiological Clues of Traumatic Craniocervical Junction Injuries Requiring Occipitocervical Fusion to Early Diagnosis

Objective

The purpose of this study is to find the clinical and radiographic characteristics of traumatic craniocervical junction (CCJ) injuries requiring occipitocervical fusion (OC fusion) for early diagnosis and surgical intervention.

Methods

We retrospectively reviewed 12 patients with CCJ injuries presenting to St. Michaels Hospital in Toronto who underwent OC fusion and looked into the following variables; (1) initial trauma data on emergency room arrival, (2) associated injuries, (3) imaging characteristics of computed tomography (CT) scan and magnetic resonance imaging (MRI), (4) surgical procedures, surgical complications, and neurological outcome.

Results

All patients were treated as acute spinal injuries and underwent OC fusion on an emergency basis. Patients consisted of 10 males and 2 females with an average age of 47 years (range, 18–82 years). All patients sustained high-energy injuries. Three patients out of 6 patients with normal BAI (basion-axial interval) and BDI (basion-dens interval) values showed visible CCJ injuries on CT scans. However, the remaining 3 patients had no clear evidence of occipitoatlantal instability on CT scans. MRI clearly described several findings indicating occipitoatlantal instability. The 8 patients with normal values of ADI (atlantodens interval interval) demonstrated atlantoaxial instability on CT scan, however, all MRI more clearly and reliably demonstrated C1/2 facet injury and/or cruciate ligament injury.

Conclusion

We advocate measures to help recognize CCJ injury at an early stage in the present study. Occipitoatlantal instability needs to be carefully investigated on MRI in addition to CT scan with special attention to facet joint and ligament integrity.

Injury patterns in motor vehicle collision-pediatric pedestrian deaths

OBJECTIVE

To describe fatal pediatric pedestrian injury patterns and correlate them with motor vehicle collision (MVC) characteristics and pedestrian kinematics using data from medicolegal death investigations of MVCs occurring in the current Canadian MV fleet and determine the applicability of the classical "Waddell's triad" comprising knee, hip (femur) or pelvis and craniocerebral injuries to present data injury patterns.

METHODS

An Injury Data Collection Form was used to extract MV, MVC, pedestrian demographic and injury information from the Office of the Chief Coroner for Ontario database using autopsy data from 2013 to 2018. Injuries were coded using the Abbreviated Injury Scale (AIS) 2015 revision. The study focused on AIS ≥3 injuries utilizing the Maximum Abbreviated Injury Scale (MAIS), MAIS by Body Region (MAISBR) and Injury Severity Score (ISS).

RESULTS

Between 2013 and 2018, there were 25 pediatric deaths. The pedestrians were either struck and run over (n = 17, 68%; 56% low speed) or struck and projected (n = 8, 32%). Twenty-two deaths were from frontal impacts; three were from reversing vehicles. Fourteen of the 17 (82.4%) run over cases occurred at low speed (<30 km/h). In 9 (36%) cases, the vehicle was turning at impact (right n = 3, left n = 6). A majority of the vehicles had a high hood edge. The head was the most severely injured (median MAISBR = 5 overall and ≤10 years; median MAISBR = 6 for 11-14 years old) followed by the neck (MAISBR = 3 overall; 6-14 years old), and the thorax (median MAISBR = 3 overall; all age groups). For the early adolescents (11-14 years old), the serious injury pattern included the abdomen (median MAISBR = 3.5). Nearly half (n = 11, 44%) sustained brainstem injuries. Over fifty percent of the 16 cases with neck injuries (n = 9, 56.3%) had atlanto-occipital or axial dislocation.

CONCLUSION

More than half of the deaths occurred during low speed run overs. MAIS ≥3 injuries trended to a dyad of head and thorax in ≤5 years old, a triad of head, neck, and thorax injuries in children 6-10 years old and a tetrad with the addition of abdominal injuries in pedestrians ≥11 years old. Waddell's triad was not applicable to the fatal cases in the present study.

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.

A rare case of bilateral occipital condyle fractures associated with inferior clivus separation fracture resulting in craniocervical dislocation: a case report and modification of the Anderson and Montesano classification is proposed

The authors report a very rare case of bilateral occipital condyle fractures (OCF) that was associated with complete separation fracture of the inferior clivus resulting in craniocervical dislocation alongside dissociation of C1-C2 joint complex. Also, a new type of the Anderson and Montesano classification system is presented with two subtypes of injuries. Type IVA occurs when the OCF is associated a clivus avulsion fracture, while Type IVB occurs when the OCF is associated with complete "en piece" separation fracture of the inferior clivus. Both Type IV injuries are considered highly unstable, and surgical fixation is the recommended treatment option.

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.

Nonsurgical Management of Combined Occipitocervical and Atlantoaxial Distraction Injuries: A Case Report

CASE

A 41-year-old man sustained occipitocervical dislocation (OCD) and atlantoaxial dislocation (AAD) injuries in a motor vehicle collision. These injuries were treated nonoperatively with a hard cervical collar and activity restrictions with an excellent result at 4-year follow-up.

CONCLUSION

OCD and AAD injuries require prompt diagnosis and immobilization. Standard of care for coexisting injuries is occipitocervical fusion; however, some patients have coexisting injuries which may prevent operative treatment. These polytrauma patients require a creative nonoperative approach with close follow-up to avoid neurologic decline.

Traumatic atlanto-occipital dislocation in children: is external immobilization an option?

OBJECT

Traumatic atlanto-occipital dislocation (AOD) is a relatively uncommon traumatic cervical spine injury characterized by disruption and instability of the atlanto-occipital joint. At many centers, management of pediatric AOD includes occipitocervical arthrodesis, but whether external immobilization without surgery is a viable treatment option for some pediatric patients is unknown. To answer this question, we analyzed our outcomes of pediatric AOD at the Hospital for Sick Children.

METHODS

We performed a retrospective chart review of all children with clinical and radiographic evidence of traumatic AOD. A total of 10 patients met criteria for traumatic AOD: 8 were treated with external immobilization alone and 2 were treated with occipitocervical arthrodesis.

RESULTS

Eight patients were treated exclusively with 3 months of halo immobilization. Two patients were treated with occipitocervical instrumentation and arthrodesis. No patient undergoing halo immobilization required subsequent operative fusion.

CONCLUSION

Halo immobilization is a safe, viable, and definitive treatment option for the selected children with AOD.

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.

Traumatic Atlanto-occipital Dislocation: Analysis of 15 Survival Cases With Emphasis on Associated Upper Cervical Spine Injuries

STUDY DESIGN

Retrospective case analyses.

OBJECTIVE

The aim of this study was to investigate the incidence and characteristics of associated upper cervical spine injuries in 15 survival cases of traumatic atlanto-occipital dislocation (AOD).

SUMMARY OF BACKGROUND DATA

Traumatic AOD is a rare and generally fatal injury. Information regarding associated upper cervical spine injuries that may affect treatment methods, outcomes, and prognosis is limited.

METHODS

Fifteen patients (11 patients with posterior-type AOD and four patients with vertical-type AOD) who survived traumatic AOD were included in this study. Plain radiographs, computed tomography, magnetic resonance imaging, and medical records were reviewed. The incidence and characteristics of associated upper and lower cervical spine and thoracolumbar spine injuries and brain injuries were evaluated.

RESULTS

Thirteen patients with traumatic AOD (11 patients with posterior-type AOD and two patients with vertical-type AOD) showed associated upper cervical spine injuries; the overall incidence was 87% (100% in posterior-type AOD and 50% in vertical-type AOD). In posterior-type AOD, eight (72.7%) patients had C1 fractures (four patients had three-part fracture, three patients had two-part fracture, and one patient had four-part fracture), four (36.4%) patients had C1 lateral mass fractures, two (18.2%) patients had transverse atlantal ligament injuries. In vertical-type AOD, two (50%) patients had C1-C2 vertical subluxation with C1 anterior arch horizontal and sagittal split fractures. In posterior-type AOD, two (18%) patients had lower cervical spine injuries and one (9%) patient had brain injury. In vertical-type AOD, one (25%) patient had thoracic spine injury, and three (75%) patients had brain injuries additionally.

CONCLUSION

Survival cases with traumatic AOD showed a high incidence of associated upper cervical spine injuries and brain injuries. High index of suspicion and careful radiologic examination are needed to investigate the presence of associated upper cervical spine injuries and brain injuries in traumatic AOD, which affects treatment, outcome, and prognosis.

LEVEL OF EVIDENCE

4.

Traumatic Atlanto-Occipital Dissociation and Atlantoaxial Instability: Concomitant Ligamentous Injuries without Neurologic Deficit: A Case Report

CASE

A 35-year-old man was involved in a motor-vehicle collision and sustained multiple thoracoabdominal and extremity injuries. A high injury burden and a normal neurologic examination contributed to a delay in diagnosing a ligamentous, combined atlanto-occipital dissociation (AOD) and vertical atlantoaxial injury (AAI). Additional imaging revealed the combined injury, and the patient underwent an occipitocervical fusion.

CONCLUSION

To our knowledge, this is the first case of a simultaneous traumatic AOD and AAI without fracture in a neurologically intact patient. Knowledge of reliable and easily applied radiographic relationships is important to expeditiously diagnose potentially lethal yet easily overlooked occipitocervical injuries.

Traumatic combined vertical atlanto-occipital and atlanto-axial dislocations with 2-part fracture of the atlas: Two case reports

RATIONALE

To our knowledge, this is the first report of traumatic combined vertical atlanto-occipital dislocation (AOD) and atlanto-axial dislocation (AAD) with 2-part fracture of the atlas.

PATIENT CONCERNS

The first case was of a 31-year-old woman admitted to the emergency room comatose after a traffic accident. The second case was of a 21-year-old woman admitted to the emergency room comatose after a fall.

DIAGNOSES

Traumatic combined vertical AOD and AAD with 2-part fractures of the atlas was diagnosed using plain radiography, 2-dimensional computed tomography, and/or magnetic resonance imaging of the cervical spine.

INTERVENTION

The first patient received immediate intubation and cardiopulmonary resuscitation in the emergency room. The second patient also received immediate intubation in the emergency room. After her vitals stabilized, she underwent occipitocervical fusion with instrumentation.

OUTCOMES

The first patient died 2 days after the accident. The second patient remained quadriplegic in a ventilatory-dependent state at 1 year after surgery. She continues to receive comprehensive rehabilitation.

LESSONS

Immediate respiratory support and surgical stabilization are important for saving lives in this kind of extremely unstable and fatal complex upper cervical spine injury.

Traumatic posterior atlantooccipital dislocation combined with type II dens fracture and C1 anterior arch fracture: Two case reports

RATIONALE

Traumatic AOD is rare but highly associated with upper cervical spine injuries. We found no references in the literature of traumatic posterior atlantooccipital dislocation (AOD) combined with type II dens fracture (Anderson-D'Alonzo classification) and C1 anterior arch fracture.

PATIENT CONCERNS

The first case was a 93-year-old male patient who was admitted to the Emergency Department complaining of incomplete quadriplegia after a fall from a height. The second was a 53-year-old male patient who visited the emergency department complaining of posterior neck pain following a high-speed motor vehicle collision.

DIAGNOSIS

Reconstructed computed tomography (CT) scans clearly demonstrated posterior AOD combined with type II dens fracture and C1 anterior arch fracture. In addition, magnetic resonance imaging (MRI) also revealed type II transverse atlantal ligament injury (Dickman's classification) in the first patient.

INTERVENTIONS

The patients chose not to undergo surgery; instead, they were immobilized with a rigid cervical brace.

OUTCOMES

The patients were lost to follow-up.

LESSONS

A thorough clinical evaluation and radiologic investigation (CT and MRI) on concomitant upper cervical injuries should be evaluated in traumatic AOD patients.

Anterior Atlantooccipital Transarticular Screw Fixation: A Cadaveric Study and Description of a Novel Technique

STUDY DESIGN

Retrospective analysis of collected data and operative experiment on human cadavers.

OBJECTIVE

To describe a novel technique of the anterior atlantooccipital (AC) transarticular screw fixation, and to analyze the pertinent anatomy with cadaveric and radiographic assessment of the feasibility, safety, and general applicability of this technique.

SUMMARY OF BACKGROUND DATA

In some situations, the posterior AC fixation techniques may not be possible, or may require supplemental fixation, which include the congenital hypoplasia, absence of the bony elements, and even revision surgery. However, an anterior screw fixation technique may add stability to further attempts at obtaining an arthrodesis.

METHODS

A detailed description of the surgical technique was presented. Three-dimensional (3D) CT reconstruction of the cranioverteral region of 30 patients were performed to determine screw entry points, target points, and proposed screw trajectories. Following screw insertion in eight fresh frozen human cadaver spine specimens, dissection verified screw location relative to structures at risk.

RESULTS

The ideal entry point is located caudal to the C1 superior facet joint in line with the medial third of the C1 superior facet. The ideal screw is directed 41.7° posteriorly in the sagittal plane and 11.6° laterally in the coronal plane with a length around 30.4 mm. The feasibility of anterior AC screw fixation was 92% (35/38 cases). There is a risk of injury to the vertebral artery and the hypoglossal nerve.

CONCLUSION

Anterior AC transarticular screw fixation is feasible and can be considered as a salvage technique or an alternative for the posterior AC fixation, as well as the supplement to the anterior occipitocervical fixation.

LEVEL OF EVIDENCE

3.

Atlanto-occipital dislocation in a patient presenting with out-of-hospital cardiac arrest: a case report and literature review

Background

Atlanto-occipital dislocation is a rare and severe injury of the upper spine associated with a very poor prognosis.

Case presentation

We report the case of a 59-year-old European man who suffered from out-of-hospital cardiac arrest following a motor vehicle accident. Cardiopulmonary resuscitation was initiated immediately by bystanders and continued by emergency medical services. After 30 minutes of cardiopulmonary resuscitation with a total of five shocks following initial ventricular fibrillation, return of spontaneous circulation was achieved. An electrocardiogram recorded after return of spontaneous circulation at the scene showed signs of myocardial ischemia as a possible cause for the cardiac arrest. No visible signs of injury were found. He was transferred to the regional academic trauma center.

Following an extended diagnostic and therapeutic workup in the emergency room, including extended focused assessment with sonography for trauma ultrasound, whole-body computed tomography, and magnetic resonance imaging (of his head and neck), a diagnosis of major trauma (atlanto-occipital dislocation, bilateral serial rip fractures and pneumothoraces, several severe intracranial bleedings, and other injuries) was made. An unfavorable outcome was initially expected due to suspected tetraplegia and his inability to breathe following atlanto-occipital dislocation.

Contrary to initial prognostication, after 22 days of intensive care treatment and four surgical interventions (halo fixation, tracheostomy, intracranial pressure probe, chest drains) he was awake and oriented, spontaneously breathing, and moving his arms and legs. Six weeks after the event he was able to walk without aid. After 2 months of clinical treatment he was able to manage all the activities of daily life on his own.

It remains unclear, whether cardiac arrest due to a cardiac cause resulted in complete atony of the paravertebral muscles and caused this extremely severe lesion (atlanto-occipital dislocation) or whether cardiac arrest was caused by apnea due the paraplegia following the spinal injury of the trauma.

Conclusions

A plausible cause for the trauma was myocardial infarction which led to the car accident and the major trauma in relation to the obviously minor trauma mechanism. With this case report we aim to familiarize clinicians with the mechanism of injury that will assist in the diagnosis of atlanto-occipital dislocation. Furthermore, we seek to emphasize that patients presenting with electrocardiographic signs of myocardial ischemia after high-energy trauma should primarily be transported to a trauma facility in a percutaneous coronary intervention-capable center rather than the catheterization laboratory directly.

The Decision-Making Process in Traumatic Lesions of the Craniovertebral Junction: An Evidence-Based Approach? Part I

Evidence-based medicine is a rather young concept, which entered the scientific literature in the early 1990s.

Traumatic atlanto-occipital dissociation: No longer a death sentence

BACKGROUND

Traumatic atlanto-occipital dissociation is considered highly unstable and was once believed to be uniformly fatal. With recent advances in prehospital care, coupled with early diagnosis and stabilization, these injuries are potentially survivable. The aim of this study was to identify potentially modifiable risk factors associated with improved outcomes after a traumatic atlanto-occipital dissociation.

METHODS

Patients with traumatic atlanto-occipital dissociation over a 17-year period were identified and stratified by age, sex, injury severity, and severity of shock. Time to diagnosis, time to and method of stabilization, and mortality were compared. Multivariable logistic regression was performed to determine which factors were independent predictors of mortality.

RESULTS

Fifty-two patients were identified with a mean age of 44, an admission Glasgow Coma Score of 8, and an Injury Severity Score of 34; of these 52 patients, 38 (73%) underwent stabilization. Overall mortality was 33%. Of the survivors, 34 patients (97%) were discharged neurologically intact. One patient was discharged with neurologic deficits. Multivariable logistic regression identified admission Glasgow Coma Score (odds ratio 0.7; 95% confidence interval 0.552-0.877) as the only independent predictor of death after traumatic atlanto-occipital dissociation.

CONCLUSION

Traumatic atlanto-occipital dissociation remains a rare injury following blunt trauma. Clinical presentation is a predictor of mortality. Prompt diagnosis is crucial in promoting rapid stabilization and improving survivability. Survival to hospital discharge portends improved functional outcome.

A Case of Asymptomatic Occipital Condyle Fracture with Incomplete Occipitocervical Dislocation: How Did It Happen?

BACKGROUND

Atlanto-occipital dislocation (AOD) is a lesion rarely observed in a trauma center, because of high mortality in the preclinical phase. The number of AOD survivors is increasing thanks to the improvement in prehospital resuscitation.

CASE DESCRIPTION

Our goal is to describe a case of incomplete atlanto-occipital dislocation presented without any neurologic, cardiorespiratory, or metabolic problems, which remained constant even after surgical treatment. Our purpose is also to discuss treatment approaches to minimize subsequent neurologic deficits.

CONCLUSIONS

We recommend a rapid immobilization with spine table and cervical collar, the consensual stabilization of hemodynamic and respiratory parameters, and a successive prompt occipitocervical stabilization. C2 should be included in the stabilization because of the ligamentous conformation of craniocervical joint.

Traumatic occipito-cervical dissociation in adults: a Middle Eastern cohort study

The objective of this study is to describe a series of cranio-cervical dissociation victims and evaluate their outcomes as well as discuss the clinical dilemmas we faced in the context of current literature evidence. This is a retrospective cohort study of traumatic occipito-cervical dissociation in five patients (three males and two females) encountered between 2010 and 2016 at a tertiary care facility in the Middle East region. All patients underwent occipito-cervical fusion using screws and rods system with mean postoperative follow-up period of 2.5 years. All patients survived, and four were independently mobile and one wheel chair bound. Most had some degree of neurological sequelae, often due to associated injuries and all complained of limited neck range of motion. Contemporary literature review shows that CT scan with MRI is often the best diagnostic modality. Surgery is usually indicated though rare cases treated conservatively have been reported. The commonest predictor of mortality is missed injury, associated head injury and wide separation between the skull base and C1 on imaging studies.

A 2D threshold of the condylar-C1 interval to maximize identification of patients at high risk for atlantooccipital dislocation using computed tomography

OBJECTIVE Measurement of the occipital condyle-C1 interval (CCI) is important in the evaluation of atlantooccipital dislocation (AOD) in pediatric trauma patients. The authors studied a large cohort of children with and without AOD to identify a 2D measurement threshold that maximizes the diagnostic yield of the CCI on cervical spine CT scans obtained in trauma patients. METHODS This retrospective, single-center study included all children who underwent CT of the cervical spine at Primary Children's Hospital from January 1, 2011, through December 31, 2014, for trauma evaluation. Bilateral CCI measurements in the coronal (3 measurements per side) and sagittal (4 measurements per side) planes were recorded. Using an iterative method, the authors determined optimal cutoffs for the maximal CCI in each plane in relation to AOD. The primary outcome was AOD requiring occipitocervical fusion. RESULTS A total of 597 pediatric patients underwent cervical spine CT for trauma evaluation: 578 patients without AOD and 19 patients with AOD requiring occipitocervical fusion. The authors found a statistically significant correlation between CCI and age (p < 0.001), with younger patients having higher CCIs. Using a 2D threshold requiring a sagittal CCI ≥ 2.5 mm and a coronal CCI ≥ 3.5 mm predicted AOD with a sensitivity of 95%, a specificity of 73%, positive predictive value of 10.3%, and negative predictive value of 99%. The accuracy of this 2D threshold was 84%. CONCLUSIONS In the present study population, age-dependent differences in the CCI were found on CT scans of the cervical spine in a large cohort of patients with and without AOD. A 2D CCI threshold as a screening method maximizes identification of patients at high risk for AOD while minimizing unnecessary imaging studies in children being evaluated for trauma.

Imaging of Atlanto-Occipital and Atlantoaxial Traumatic Injuries: What the Radiologist Needs to Know

Approximately one-third of all cervical spine injuries involve the craniocervical junction (CCJ). Composed of the occiput and the first two cervical vertebrae, this important anatomic landmark, in conjunction with an intricate ligamentous complex, is essential to maintaining the stability of the cervical spine. The atlantoaxial joint is the most mobile portion of the spine, predominantly relying on the ligamentous framework for stability at that level. As acute onsite management of trauma patients continues to improve, CCJ injuries, which often lead to death onsite where the injury occurred, are increasingly being encountered in the emergency department. Understanding the anatomy of the CCJ is crucial in properly evaluating the cervical spine, allowing the radiologist to assess its stability in the trauma setting. The imaging findings of important CCJ injuries, such as atlanto-occipital dissociation, occipital condyle fractures, atlas fractures with transverse ligament rupture, atlantoaxial distraction, and traumatic rotatory subluxation, are important to recognize in the acute setting, often dictating patient management. Thin-section multidetector computed tomography with sagittal and coronal reformats is the study of choice in evaluating the extent of injury, allowing the radiologist to thoroughly evaluate the stability of the cervical spine. Furthermore, magnetic resonance (MR) imaging is increasingly being used to evaluate the spinal soft tissues and ligaments, and to identify associated spinal cord injury, if present. MR imaging is also indicated in patients whose neurologic status cannot be evaluated within 48 hours of injury. .

Occipitocervical dissociation-incidence, evaluation, and treatment

Traumatic occipitocervical dissociation (OCD) results from ligamentous injury to the craniocervical junction and is associated with a high rate of mortality and significant neurologic morbidity. The diagnosis is frequently missed on initial lateral cervical spinal radiographs mainly due to inadequate visualization of radiological landmarks and low degree of suspicion. Widespread availability of multidetector computed tomography (MDCT) of the spine and development of better diagnostic radiological criteria has allowed timely diagnosis and good clinical outcome following posterior occipitocervical fusion and instrumentation for a pathology that was once considered uniformly fatal. The present paper reviews the clinical features, diagnosis, and management of OCD in light of most recent literature.

Prognostic factors in traumatic atlanto-occipital dislocation

Traumatic atlanto-occipital dislocation (AOD) is an ominous injury with high mortality and morbidity in trauma patients. Improved survival has been observed with advancements in pre-hospital and hospital care. Furthermore, high quality imaging studies are accessible at most trauma centers; these are crucial for prompt diagnosis of AOD. The objective of this study is to perform a comprehensive literature review of traumatic AOD, with specific emphasis on identifying prognostic factors for survival. A review of the literature was performed using the Medline database for all traumatic atlanto-occipital articles published between March 1959 and June 2015; 141 patients from 60 total studies met eligibility criteria for study inclusion. A binary logistic regression model was utilized to identify prognostic factors. The analysis assessed age, sex, spinal cord injury (SCI), traumatic brain injury (TBI), polytrauma injury (PI), and Traynelis AOD Classification. Only TBI was statistically significantly associated with death (OR 8.05 p<0.05); SCI did not reach statistical significance for predicting mortality in AOD patients (OR 1.25 p>0.05). Age, sex, PI, and Traynelis AOD Classification did not meet significance to predict mortality in AOD patients. We found that patients with TBI are eight times more likely to die than patients without TBI. A high degree of suspicion for AOD during pre-hospital care, as well as, prompt diagnosis and management in the trauma center play a key role in the treatment of this devastating injury. The relationship between survival and factors such as TBI and SCI should be further explored.

Occult Cranial Cervical Dislocation: A Case Report and Brief Literature Review

Study Design. Retrospective case report and review. Objective. Cranial cervical dislocation (CCD) is commonly a devastating injury. Delay in diagnosis has been found to lead to worse outcomes. Our purpose is to describe a rare case of occult cranial cervical dislocation (CCD) and use it to highlight key clinical and radiographic findings to ensure expedited diagnosis and proper management avoiding delays and subsequent neurologic deterioration. Method. Case report with literature review. Results. We describe a unique case of occult cranial cervical dislocation where initial imaging of the cervical spine failed to illustrate displacement of the occipital-cervical (O-C1) articulation or C1-C2 articulation. Careful evaluation of subtle radiographic clues suggested a more severe injury than initial review. Additional imaging was obtained due to these subtle clues confirming true cranial cervical dislocation allowing subsequent treatment with no neurologic sequelae. Conclusion. A high index of suspicion of CCD may prevent injury in select patients who present without gross cord compromise. Careful consideration of associated fractures, soft tissue injuries, and mechanism of injury are essential clues to the correct diagnosis and management of injuries to the craniocervical junction (CCJ).

Traumatic atlantooccipital dislocation: comprehensive assessment of mortality, neurologic improvement, and patient-reported outcomes at a Level 1 trauma center over 15 years

BACKGROUND CONTEXT

Only Level 3 evidence exists for the diagnosis and treatment of atlantooccipital dislocation (AOD) with few studies examining mortality, neurologic improvement, and patient-reported outcomes (PROs).

PURPOSE

First, the aim was to determine: the incidence of AOD, 90-day surgical morbidity and mortality after AOD, patient factors that may be associated with delayed or missed diagnosis, and factors that were associated with mortality and neurologic improvement after AOD. Secondly, the aim was to quantify the pain, disability, and quality of life experienced by patients surviving AOD.

STUDY DESIGN/SETTING

This was a retrospective cohort study.

PATIENT SAMPLE

A total of 5,337 consecutive spine computed tomography traumagrams from 1997 to 2012 were included.

OUTCOME MEASURES

Mortality, neurologic improvement, complications, EuroQol five dimensions (EQ-5D), Neck Disability Index (NDI), Numeric Rating Scale (NRS)-neck, NRS-arm, and return-to-work were the outcome measures.

METHODS

Patients were considered to have AOD if they met one of the following radiographic criteria: basion-dens interval greater than 10 mm; basion-axial interval: anterior displacement greater than 12 mm or posterior displacement greater than 4 mm between the basion and posterior C2 line; and condyle to C1 interval greater than 1.4 mm. Linear regression analysis was performed to identify factors associated with 90-day mortality, neurologic improvement, and missed diagnosis. Patient-reported outcomes were assessed via phone interview.

RESULTS

Thirty-one patients met radiographic criteria for AOD; an incidence of 0.6% over 15 years. Twenty-one (68%) patients were treated with occipital cervical fusion. At 90 days postoperatively, there were no new neurologic deficits or reoperations. Eight (26%) patients died within 90 days. All patients who died had no documented AOD diagnosis and were not treated surgically. Missed AOD diagnosis was the strongest predictor of mortality. Younger age, lower Glasgow Coma Score, lower Injury Severity Score (ISS) score, and worse initial American Spinal Injury Association (ASIA) score were significantly associated with greater neurologic improvement. Higher ISS score and better ASIA score were significantly associated with missed AOD diagnosis. The average PROs metrics at time of telephone follow-up were as follows: EQ-5D=0.73±0.19, NDI=30.89±18.57, NRS-neck=2.33±2.21, NRS-arm=2.00±2.54. Of the patients with follow-up data, four were employed full-time, and five were receiving disability.

CONCLUSIONS

Our work suggests that failure to diagnose AOD is a powerful predictor of mortality. Higher ISS scores and better neurologic presentation were significantly associated with missed diagnosis. Craniocervical arthrodesis preserved neurologic function with low complication rate and unexpectedly high PROs and return-to-work. These results must be carefully interpreted because it is unclear whether missed AOD diagnosis accompanies another death-causing injury (eg, traumatic brain injury) or if failure to treat AOD contributes to mortality in a multifactorial manner.

Management of acute traumatic spinal cord injury

OPINION STATEMENT

Spinal cord injury (SCI) causes significant morbidity and mortality. Clinical management in the acute setting needs to occur in the intensive care unit in order to identify, prevent, and treat secondary insults from local ischemia, hypotension, hypoxia, and inflammation. Maintenance of adequate perfusion and oxygenation is quintessential and a mean arterial pressure >85-90 mm Hg should be kept for at least 1 week. A cervical collar and full spinal precautions (log-roll, flat, holding C-spine) should be maintained until the spinal column has been fully evaluated by a spine surgeon. In patients with SCI, there is a high incidence of other bodily injuries, and there should be a low threshold to assess for visceral, pelvic, and long bone injuries. Computed tomography of the spine is superior to plain films, as the former rarely misses fractures, though caution needs to be exerted as occipitocervical dislocation can still be missed. To reliably assess the spinal neural elements, soft tissues, and ligamentous structures, magnetic resonance imaging is indicated and should be obtained within 48-72 h from the time of injury. All patients should be graded daily using the American Spinal Injury Association classification, with the first prognostic score at 72 h postinjury. Patients with high cervical cord (C4 or higher) injury should be intubated immediately, and those with lower cord injuries should be evaluated on a case-by-case basis. However, in the acute setting, respiratory mechanics will be disrupted with any spinal cord lesion above T11. Steroids have become extremely controversial, and the professional societies for neurosurgery in the United States have given a level 1 statement against their use in all patients. We, therefore, do not advocate for them at this time. With every SCI, a spine surgeon must be consulted to discuss operative vs nonoperative management strategies. Indications for surgery include a partial or progressive neurologic deficit, instability of the spine not allowing for mobilization, correction of a deformity, and prevention of potential neurologic compromise. Measures to prevent pulmonary emboli from deep venous thromboembolisms are necessary: IVC filters are recommended in bedbound patients and low-molecular weight heparins are superior to unfractionated heparin. Robust prevention of pressure ulcers as well as nutritional support should be a mainstay of treatment. Lastly, it is important to note that neurologic recovery is a several-year process. The most recovery occurs in the first year following injury, and therefore aggressive rehabilitation is crucial.

Upper cervical spine trauma

Injuries to the upper cervical spine are potentially lethal; thus, full characterization of the injuries requires an accurate history and physical examination, and management requires an in-depth understanding of the radiographic projection of the craniocervical complex. Occipital condyle fractures may represent major ligament avulsions and may be highly unstable, requiring surgery. Craniocervical dissociation results from disruption of the primary osseoligamentous stabilizers between the occiput and C2. Dynamic fluoroscopy can differentiate the subtypes of craniocervical dissociation and help guide treatment. Management of atlas fractures is dictated by transverse alar ligament integrity. Atlantoaxial dislocations are rotated, translated, or distracted and are treated with a rigid cervical orthosis or fusion. Treatment of odontoid fractures is controversial and dictated by fracture characteristics, patient comorbidities, and radiographic findings. Hangman's fractures of the axis are rarely treated surgically, but atypical patterns and displaced fractures may cause neurologic injury and should be reduced and fused. Management of injuries to the craniocervical junction remains challenging, but good outcomes can be achieved with a comprehensive plan that consists of accurate and timely diagnosis and stabilization of the craniocervical junction.

Traumatic atlanto-occipital dislocation in children

Although once considered an invariably fatal injury, improvements in diagnosis and management have made atlanto-occipital dislocation (AOD) a survivable injury. MRI is the preferred imaging modality; occasionally, flexion/extension/distraction fluoroscopy may be required to determine craniovertebral stability. Early surgical stabilization is recommended for all children with AOD. Early occipitocervical fusion using screws in combination with a rod or plate, or sublaminar wires with a contoured rod, coupled with autograft bone, provide immediate stabilization and a high fusion rate. Halo immobilization and traction are contraindicated in the management of AOD in children because of the risk of displacement of the injured occipitocervical joint. Postoperative hydrocephalus is frequent and should be suspected when neurologic decline occurs after fixation. Nearly half of children who survive AOD will have residual neurologic deficits.

Associated injuries in children and adolescents with spinal trauma

BACKGROUND

Over half of children and adolescents with spinal trauma have associated injuries, most commonly involving the appendicular skeleton, head and neck, and thorax. The incidence and characteristics of these associated injuries have been well described, but to our knowledge there has been no evaluation of the relationship between the injury characteristics and the patient age.

METHODS

Data were obtained from the trauma registries of the local pediatric and adult level 1 trauma centers, and patients aged 0 to 19 years with spinal trauma were identified. For analysis, patients were divided into 3 age groups: 0 to 3, 4 to 12, and 13 to 19 years. Associated injuries were divided into 5 groups: head, thoracic, abdominal, appendicular skeletal fracture, and neurological.

RESULTS

Overall, 25 patients had isolated dislocations and 307 patients had 366 spinal fractures or fracture-dislocations: 36% cervical, 31% thoracic, and 51% lumbar. Most (84%) of the injuries occurred in the 13- to 19-year-old group. Sixty-two percent of patients had associated injuries, most commonly thoracic injuries (pulmonary contusion, pneumothorax, rib fracture); 45% had multilevel spinal fractures, 39% of which were noncontiguous. Nearly three fourths of the noncontiguous fractures occurred in a different spinal region; cervical fracture with concomitant thoracic fracture was the most frequent pattern.

CONCLUSIONS

This large series of consecutive patients highlights several important concepts concerning pediatric spinal fractures, including age-related patterns of injury, frequent associated injuries, and a high rate of multiple spinal injuries, especially noncontiguous injuries. It also emphasizes the importance of careful full-body examination and imaging of the entire spine in children and adolescents with a known spinal injury.

LEVEL OF EVIDENCE

Level IV-case series.

Incidence and outcome of atlanto-occipital dissociation at a level 1 trauma centre: a prospective study of five cases within 5 years

BACKGROUND

Prospective evaluation of atlanto-occipital dissociations (AODs) at a level 1 trauma centre within 5 years.

METHODS

Over a period of 5 years (2005-2009), all CT scans of the skull base and the upper cervical spine due to traumatic injuries were prospectively entered into a database. Furthermore, in cases of confirmed AOD all empirical data were prospectively collected. A more detailed data analysis of all AOD patients was conducted 2 years post-trauma. If required, another prospective follow-up was performed.

RESULTS

2,616 CT scans were performed in total. Out of these, there were five male patients with confirmed AOD. Thus, the total incidence was 0.2 %. AOD was associated with occipital condyle fractures in three out of the five cases. Three out of five patients (60 %) died due to the severity of the injury. It was possible to stabilise two patients surgically with a clinical/radiological follow-up 2 years post-surgery. At that time, one patient had an incomplete tetraplegia and was wheelchair ridden without needing ventilation, while the other patient suffered from post-traumatic stress disorder, but was able to walk and live alone.

CONCLUSIONS

AOD is a rarely seen injury, even in a level 1 trauma centre, and is associated with high morbidity and mortality. However, it is possible for adults to survive this severe occipito-cervical injury after surgical repair while maintaining the ability to walk. All the results and recommendations are still based on a low level of evidence, due to the low incidence of this injury.

Traumatic Atlanto-occipital Dislocation (AOD)

OBJECTIVE

Traumatic atlanto-occipital dislocation (AOD) results from high energy trauma and is an uncommon and usually fatal injury due to an injury to the cervicomedullary junction. Recently, improved prehospital management, early diagnosis and effective treatment led to increasing reports of survival. This study of patients with AOD initial imaging modalities recognizes the clinical features and diagnostic considerations for a quick diagnosis.

METHODS

In this article, five survived adult patients with traumatic AOD are presented and retrospectively reviewed. Diagnosis was made by lateral cervical spine x-ray, cervical computed tomography (CT), or magnetic resonance imaging(MRI). Treatment consisted of early immobilization, respiratory support, and subsequent occipitocervical fusion.

RESULTS

Four patients were male and the other one was female. Three were diagnosed early and the others were delayed in confirmations. One was type I AOD and four were type II AOD. All patients were applied occipitocervical fusion. Two cases were worse; neurological states and the other three that showed no change. Lateral X-ray film of all patients in the prevertebral soft tissue swelling at the C2 level was noted. The mean thickness of prevertebral soft tissue C2 level was 17.88 mm(15.18 to 20.17mm). Two were in the normal range of dens-basion index(DBI), three showed abnormalities, and Power's ratio was abnormal in 3 patients.

CONCLUSION

As for damages caused by a strong external force in patients with severe prevertebral soft tissue swelling at C2 level abnormaly, the doctor determines whether more should be carefully AOD and considers 3D CT or MRI to confirm AOD in these patients.

Pontomedullary lacerations and concomitant head and neck injuries: their underlying mechanism. A prospective autopsy study

It is a well-documented fact that pontomedullary lacerations (PML) occur as a result of severe craniocervical injury, but their underlying mechanism has yet to be fully clarified. The aim of this prospective study has been to give greater insight into the underlying mechanism of PML through determining the site of blunt head-impact, as well as the presence of concomitant head and neck injuries in cases of brainstem PML. A total of 56 cases with partial PML have been analysed for this study. The case group was composed of 40 men and 16 women, averaging in age 44.2 ± 19.2 years and consisting of 7 motorcyclists, 4 bicyclists, 18 car occupants, 16 pedestrians, and 10 victims of falls from a height, as well as 1 victim of a fall from standing height. The presented study has shown that there are several possible mechanisms of PML. Impact to the chin, with or without a skull base fracture, most often leads to this fatal injury, due to the impact force transmission either through the jawbone or vertebral column; most likely in combination with a fronto-posterior hyperextension of the head. Additionally, lateral head-impacts with subsequent hinge fractures and PML may also be a possible mechanism. The jawbone and other facial bones are able to act as shock absorbers, and their fracture may diminish the energy transfer towards the skull and protect the brain and brainstem from injury. The upper cervical spine can act as damper and energy absorber as well, and may prevent any occurrence of fracture to the base of the skull.

Motion within the unstable cervical spine during patient maneuvering: the neck pivot-shift phenomenon

BACKGROUND

Cervical extrication collars are applied to millions of blunt trauma victims despite the lack of any evidence that a collar can protect against secondary injuries to the cervical spine. Cadaver studies support that in the presence of a dissociative injury, substantial motion can occur within the occipitocervical spine with collar application or during patient transfers. Little is known about the biomechanics of cervical stabilization; hence, it is difficult to develop and test improved immobilization strategies.

MATERIALS

Severe unstable injuries were created in seven fresh whole human cadavers. Rigid collars were applied with the body in a neutral position. Computed tomographic examinations were obtained before and after tilting the body or backboard as would be done during patient transport or to inspect the back. Relative displacements between vertebrae at the site of the injury were measured from the Computed tomographic examinations. The overall relative alignment between body and collar was assessed to understand the mechanisms that may facilitate motion at the injury site.

RESULTS

Intervertebral motion averaged 7.7 mm±6.8 mm in the axial plain and 2.9 mm±2.5 mm in the cranial-caudal direction. The rigid collars appeared to create pivot points where the collar contacts the head in the region under the ear and where the collar contacts the shoulders.

DISCUSSION

Rigid cervical collars appear to create pivot points that shift the center of rotation lateral to the spine and contribute to the intervertebral motions that were measured. Immobilization strategies that avoid these neck pivot-shift phenomena may help to reduce secondary injuries to the cervical spine. The whole cadaver model with simulation of patient maneuvers may provide an effective test method for cervical immobilization.

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.

Occipitoatlantal dislocation

Occipitoatlantal dislocation (OAD) can be devastating. This injury may be fatal in many cases, but more survivors are reported because of improvements in diagnosis and treatment. This article describes the diagnosis and treatment of OAD. To diagnose and treat OAD appropriately, neurosurgeons must have a detailed understanding of the anatomy of the craniocervical junction. Various radiographic criteria are used to establish the diagnosis of OAD. A destabilizing injury such as OAD requires surgical fixation. Many surgical techniques are available for fixation of the craniocervical junction. Future studies will continue to refine the diagnostic criteria for OAD and to develop improved methods for craniocervical stabilization.

Occipital condyle fractures

OBJECTIVE

The anatomy, clinical presentation, radiologic evaluation, treatment, and outcome of occipital condyle fractures are reviewed.

METHODS

We review and discuss the literature on occipital condyle fractures.

RESULTS

Occipital condyle fractures are best diagnosed with computed tomography. The neurologic presentation is variable. The majority of these injuries may be treated nonoperatively, but an occipitocervical fusion is necessary to restore stability across the craniovertebral junction.

CONCLUSION

Occipital condyle fractures are a rare but serious injury that requires prompt diagnosis and treatment.

Intraarticular atlantooccipital fusion for the treatment of traumatic occipitocervical dislocation in a child: a new technique for selective stabilization with nine years follow-up

STUDY DESIGN

A case report of traumatic atlantooccipital dislocation (AOD) managed by intraarticular-posterior fusion from a posterior approach at the C0-C1 level with preservation of C1-C2 motion.

OBJECTIVE

To present a new technique for atlantooccipital fusion with long-term follow-up.

SUMMARY OF BACKGROUND DATA

There is an increasing number of patients with AOD who have preservation of neurologic function. The most frequent method used to treat this condition is occipitocervical fusion. There has been a tendency in recent years to minimize the extent of stabilization, performing occipitoatlantal fusion only. However, it is difficult to achieve a solid fusion between C0 and C1, and the long-term effect of the insufficiency of lig. alaria on C0-C2 stability is unknown. The authors present a modified technique of C0-C1 fusion that aims to enhance fusion and achieve greater stability.

METHODS

A 11-year-old child with AOD was initially treated unsuccessfully with a halo device for 3 months. As instability persisted, an isolated C0-C1 fusion was performed from a posterior approach. This anatomically based intraarticular fusion technique comprises removal of the articular cartilage of the atlantooccipital joints, and cancellous bone autografting at the atlantooccipital joints and between the occiput and posterior arch of C1, supported by an occipital plate linked by rods to lateral mass screws in the atlas.

RESULTS

This technique of increased bony fusion surface and internal fixation provided an excellent result with full recovery of minor neurologic deficits. At long-term follow-up, 9 years after surgery, the patient was free of signs and symptoms; solid fusion of the C0-C1 joint, and normal values for rotation of the C1-C2 segment were recorded.

CONCLUSION

Intraarticular and posterior fusion of the atlantooccipital joint was able to provide an excellent long-term clinical outcome in the treatment of traumatic AOD in a child. This is the first report of an intraarticular fusion of the C0-C1 segment and the longest follow-up published on isolated C0-C1 stabilization.

Timely recognition of traumatic atlanto-occipital dislocation in a child based on occipital condyle-C1 interval analysis: excellent neurological recovery

A case of atlanto-occipital dislocation (AOD) is presented to illustrate the importance of subtle imaging findings and the occipital condyle-C1 interval (CCI) measurement in the evaluation of high cervical spine injury. Although AOD is commonly considered to be fatal, recently there have been an increasing number of reports of children surviving this injury. Prompt recognition and treatment of AOD are crucial for survival. The authors present a case of an 8-year-old boy who sustained a destabilizing injury without bone disruption but with ligamentous tears that rendered his cervical spine unstable from the occiput to the C-1 level. On admission, imaging findings were consistent with tectorial membrane damage, perimedullary subarachnoid hemorrhage, and extraaxial blood from the clivus to the C-2 level. Most standard cervical spine radiological indices were within normal limits except the CCI. After initial management in a cervical collar, the patient was placed in halo vest, and subsequently underwent occiput to C-3 fusion. Timely recognition of the injury and subsequent craniocervical stabilization with internal fixation resulted in full neurological recovery. This report supports CCI as a valuable index for the prompt recognition of AOD. It also supports recent literature suggesting that AOD is a survivable injury with the possibility for an excellent neurological recovery.

Combined occipital-cervical and atlantoaxial disassociation without neurologic injury: case report and review of the literature

STUDY DESIGN

Case report and literature review.

OBJECTIVE

To discuss the diagnosis, limitations, and treatment of combined occipital-cervical and atlantoaxial disassociation with normal neurologic function.

SUMMARY OF BACKGROUND DATA

Injuries to the craniocervical junction can lead to devastating neurologic deficits. Occipital-cervical disassociation is a well-documented injury pattern that can lead to pain, spinal cord injury, and death. Early diagnosis and treatment can preserve neurologic function. Combined injuries to both the occipital-cervical and atlantoaxial segments are less common and, to date, have only been described with severe neurologic injury.

METHODS

Retrospective review of a case. Literature review was performed through Medline and Pubmed searches.

RESULTS

This is the first case to present a combined occipital-cervical and atlantoaxial disassociation with a neurologically intact patient. Initial physical examination was limited, but early imaging revealed evidence of instability. Early diagnosis and early (< 24) surgical stabilization was performed with no complications and neurologic preservation. One-year follow-up visit revealed normal neurologic examination with neck pain VAS = 2/10 and neck disability index = 6.

CONCLUSION

Combined injuries to the occipital-cervical and atlantoaxial can result in upper cervical instability. Despite previous reports, neurologic preservation remains a possibility in this injury pattern. Limitations in physical examination and radiographic imaging persist, but early diagnosis and surgical stabilization may improve neurologic outcomes.

Comprehensive computed tomography assessment of the upper cervical anatomy: what is normal?

BACKGROUND CONTEXT

High-speed computed tomography (CT) exams have replaced traditional radiographs for assessment of cervical spine injuries in many emergency departments. Recent evidence demonstrates that even subtle displacements can indicate significant upper cervical spine injuries. Many different anatomical measurements have been described in the upper cervical spine to date, most of them based on X-ray. The range of anatomical relationships that exist in an uninjured population must be known to reliably detect abnormal relations. The measurements with the lowest normal variation are likely to be most useful in detecting injuries.

PURPOSE

The purpose of this study was to describe the normal quantitative anatomical relationships as well as the threshold measurements most likely to detect injury in the upper cervical spine.

STUDY DESIGN/SETTING

Retrospective anatomical case review.

PATIENT SAMPLE

Seventy-six thin-sliced cervical CT scans randomly selected from a trauma population, all negative for injury in the cervical spine.

METHODS

Forty-two different anatomical measurements were made of the upper cervical spine. These included traditional historical measurements and other detailed dimensions to characterize occipitocervical (OC) and atlantoaxial (AA) joint relationships.

RESULTS

After review of all the anatomical measurements performed in the upper cervical spine, direct measurements of the joint space had the least variation. The mean OC joint space was 0.6mm, with an upper 95% confidence interval (CI) of 1mm at the most anterior or posterior aspects of the joints. This was true for both sagittal and coronal measurements. The mean AA joint space was 0.6mm, with an upper 95% CI of 1.2mm at the lateral aspect of the joint on the coronal image only. The midsagittal structures demonstrated significantly higher standard deviation and variability.

CONCLUSIONS

These results revealed consistently narrow joint spaces and left-right symmetry in the upper cervical spine joints that do not vary according to demographics. There was distinctly greater consistency in the coronal plane, which enabled more precise diagnostic measurement and side-to-side comparison of measurements. This precision will enable more accurate identification of abnormal scans, which should prompt consideration for additional workup. Thus, better understanding of these relationships may enable earlier detection of subtle craniocervical dissociative injuries based on CT scan data. This is important, because the only evidence of a severe injury on CT can be subtle misalignment.

Identifying survivors with traumatic craniocervical dissociation: a retrospective study

BACKGROUND

Traumatic craniocervical dissociation (CCD), which includes atlanto-occipital dissociation and vertical distraction between C1-C2, is often an immediately fatal injury that has increasingly been associated with survival to the hospital. Our aim was to identify survivors of CCD based on clinical presentation.

METHODS

We retrospectively reviewed the Harborview Medical Center Trauma Registry and the King County Medical Examiners database from 2001 to 2006. Patients>or=12 y old were identified by ICD-9 code, radiographic diagnosis on lateral cervical spine films, and CT. We examined age, gender, mechanism of injury, presentation and prehospital and hospital interventions, and radiographic findings to distinguish survivors and non-survivors.

RESULTS

Of 69 patients with CCD, 47 were diagnosed post mortem, 22 were diagnosed in hospital, and seven survived to discharge. When comparing survivors and non-survivors, age, gender, and injury severity score were not significant. Survivors had significantly higher GCS, and were more likely to be normotensive; none had cervical cord injury; 80% of non-survivors had a basion-dental interval (BDI) of >or=16mm.

CONCLUSIONS

Trauma patients diagnosed with CCD in the ED, with cervical cord injury, requiring CPR, and with GCS of 3 will not survive their injury. Wider BDI is associated with mortality.