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

The establishment of a novel upper cervical complex fracture classification system

BACKGROUND CONTEXT

Upper cervical complex fractures are associated with high rates of neurological damage and mortality. The Dickman's classification is widely used in the diagnosis of upper cervical complex fractures. However, it falls short of covering the full spectrum of complex fractures. This limitation hinders effective diagnosis and treatment of these injuries.

PURPOSE

To address the diagnostic gap in upper cervical complex fractures, the study introduces a novel classification system for these injuries, assessing its reliability and usability.

STUDY DESIGN

Proposal of a new classification system for upper cervical complex fractures.

PATIENT SAMPLE

The study comprised the clinical data of 242 patients with upper cervical complex fractures, including 32 patients treated at our hospital, along with an additional 210 cases from the literature.

OUTCOME MEASURES

The interobserver and intra-observer reliability (kappa coefficient, κ) of this classification system were investigated by 3 spine surgeons. The 3 researchers independently reevaluated the upper cervical complex fracture classification system 3 months later.

METHODS

The proposed classification categorizes upper cervical complex fractures into 3 main types: Type I combines odontoid and Hangman's fractures into 2 subtypes; Type II merges C1 with odontoid/Hangman's fractures into 3 subtypes; and Type III encompasses a combination of C1, odontoid, and Hangman's fractures, divided into 2 subtypes. Meanwhile, a questionnaire was administered in 15 assessors to evaluate the system's ease of use and clinical applicability.

RESULTS

A total of 45 cases (18.6%) unclassifiable by Dickman's classification were successfully categorized using our system. The mean κ value of inter-observer reliability was 0.783, indicating substantial reliability. The mean κ value of intraobserver reliability was 0.862, indicating almost perfect reliability. Meanwhile, thirteen assessors (87.7%) stated that the classification system is easy to remember, easy to apply, and they expressed intentions to apply it in clinical practice in the future.

CONCLUSIONS

This system not only offers high confidence and reproducibility but also serves as a precise guide for clinicians in formulating treatment plans. Future prospective applications are warranted to further evaluate this classification system.

Management of a 9-Month-Old Infant with Traumatic Atlanto-occipital Dislocation and Atlantoaxial Instability: A Case Report

CASE

We report a 9-month-old girl who was involved in a motor vehicle collision and sustained atlanto-occipital dislocation (AOD), atlantoaxial instability, and a C2 synchondrosis fracture. Initial management with a halothoracic vest for damage control failed to maintain reduction, necessitating definitive posterior occipitocervical fusion.

CONCLUSION

Traumatic AOD is a rare injury, most common in children following high-energy trauma. Early diagnosis and timely intervention are imperative for improved clinical outcomes. Even in young patients with small anatomy, with careful preoperative planning, occipitocervical fusion is effective and safe with successful postoperative outcomes.

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.

Mechanisms and risk factors associated with spinal cord injury, facet fracture, and level of dislocation, in occupants with cervical spine dislocations sustained in motor vehicle crashes

OBJECTIVE

Motor vehicle crashes (MVCs) are the leading cause of cervical spine dislocation. The mechanisms underlying this injury are unclear, limiting the development of injury prevention devices and strategies. MVC databases contain occupant, medical, vehicle, and crash details that are not routinely collected elsewhere, providing a unique resource for investigating injury mechanisms and risk factors. In this study, a comprehensive standalone analysis of cervical spine dislocations captured in MVC databases was performed.

METHODS

Epidemiologic, biomechanical, and injury data were extracted from three MVC databases. Logistic regression models were developed to determine the occupant, vehicle, and crash characteristics, as well as the global (inertial or impact) and regional (flexion, compression, etc.) loading mechanisms associated with the level of cervical spine dislocation (axial or sub-axial), and the occurrence of spinal cord injury (SCI) or facet fracture concomitant to dislocation.

RESULTS

There was no association between global or regional injury mechanisms and the level of cervical spine dislocation. Sub-axial dislocations were typically due to head/face impact with the airbag or upper interior components, or a result of seatbelt restraint of the torso. Higher occupant age, lower BMI, partial/no ejection, and frontal and side configuration crashes (compared to rollovers) were associated with a higher likelihood of sub-axial, versus axial, dislocation. Amongst all dislocations, an increased likelihood of SCI was associated with impact injuries, airbag non-deployment, and complete ejection, while concomitant facet fracture was associated with the presence of regional compression. Severe crashes, partial ejections, and "utility vehicles" and "vans and trucks" (compared with "passenger vehicles") were associated with a higher risk of facet fracture concomitant to sub-axial dislocation.

CONCLUSION

The findings of this study may be used to inform the loading modes to be simulated in future ex vivo or computational models seeking a better understanding of cervical spine dislocations.

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.

[Atlanto-occipital dislocation-A challenge with respect to making the diagnosis and treatment]

BACKGROUND

The correct diagnosis and treatment of the atlanto-occipital dislocation (AOD) remains a major challenge.

OBJECTIVE

To evaluate the different radiological diagnostic criteria for AOD and discuss potential treatment strategies based on a case with AOD and additional fracture of the atlas.

MATERIAL AND METHODS

A 29-year-old male patient is presented who suffered from AOD with concomitant fracture of the anterior and posterior arches of the atlas with rotational atlantoaxial dislocation following an accident in forestry. The following parameters were evaluated for the diagnosis and assessment of postoperative reduction: Powers ratio, the X‑lines-method, Wackenheim line, basion-dens interval (BDI), basion-axial interval (BAI) and occipital condyle-C1 interval (CCI).

RESULTS

Stabilization was performed by occipitocervical spondylodesis from C0 to C2/3. For final reduction it was necessary to reduce the malrotation of the atlas. In the presented case, the revised CCI proved to be a sensitive and valid yet practical parameter. Powers' ratio and the BDI were less suited for assessing the diagnosis. The X‑lines-method, Wackenheim line and the BAI did not adequately detect the pathological situation.

DISCUSSION

The AOD is a severe injury requiring immediate correct diagnosis for later adequate treatment results. Among the published parameters, the revised CCI proved to be a practical and valid parameter to detect AOD. For definitive treatment, the operative occipitocervical stabilization is regarded as the method of choice.

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.

A Novel Treatment of Pediatric Atlanto-Occipital Dislocation with Nonfusion Using Muscle-Preserving Temporary Internal Fixation of C0-C2: Case Series and Technical Note

Study Design  Case series with surgical technical note. Objectives  This article reports experiences and results of muscle-preserving temporary C0-C2 fixation for the treatment of atlanto-occipital dislocation (AOD). Methods  AOD is a rare injury caused by high-energy trauma, occurring in less than 1% of pediatric trauma patients. Recommended treatment is C0-C2 fusion which, however, will result in significant loss of mobility in the craniocervical junction (CCJ), especially C1-C2 rotation. An alternative approach, with the ability of preserving mobility in the C1-C2 segment, is a temporary fixation that allows the ligaments to heal, after which the implants can be removed to regain function in the CCJ joints. By using a muscle-preserving approach and navigation for the C2 screws, a relatively atraumatic fixation of the CCJ can be achieved with motion recovery after implant removal. Results  We present two cases of AOD treated with temporary fixation. A 12-year-old boy involved in a frontal car collision, as a strapped back seat passenger, was treated with temporary C0-C2 fixation for 10 months. Follow-up at 11 months after implant removal included clinical evaluation, computed tomography, magnetic resonance imaging (MRI), and flexion-extension X-rays. He was free of symptoms at follow-up. The CCJ was radiographically stable and he had 45 degrees of C1-C2 rotation. A 7-year-old girl was hit by a car as she got off a bus. She was treated with temporary fixation for 4 months after which the implant was removed. Follow-up at 8 years included clinical evaluation and MRI in rotation. She was free of symptoms. The ligaments of the CCJ appeared normal and her C1-C2 rotation was 30 degrees. Conclusion  C0-C2 fixation without fusion allows the CCJ ligaments to heal in pediatric AOD. By removing the implants after ligament healing, rotation in the C1-C2 segment can be regained without subsequent instability. Both our patients tolerated the treatment well and were free of symptoms at follow-up. By using minimally invasive muscle-preserving technique and navigation, temporary fixation of the CCJ can be achieved with minimal damage to the soft tissues allowing recovery of almost normal function after implant removal.

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.

Our experiences in patients with atlanto-occipital dislocation: A case series with literature review

Atlanto-occipital dislocation (AOD) is an injury to the upper cervical spine that occurs after trauma. This injury is associated with a high mortality rate. According to studies, 8%-31% of deaths caused by accidents are due to AOD. Due to the improvement in medical care and diagnosis, the rate of related mortality has decreased. Five patients with AOD were evaluated. Two cases had type 1, one case had type 2, and two other patients had type 3 AOD. All patients had weakness in the upper and lower limbs and underwent surgery to fix the occipitocervical junction. Other complications in patients were hydrocephalus, 6 nerve palsy, and cerebellar infarction. All patients improved in follow-up examinations. AOD damage is divided into four groups: anterior, vertical, posterior, and lateral. The most common type of AOD is type 1 and the most instability is type 2. There are neurological and vascular injuries due to pressure on regional components; vascular injuries are associated with high mortality rate. In most patients, their symptoms improved after surgery. AOD requires early diagnosis and immobilization of the cervical spine along with maintaining the airway to save the patient's life. It is necessary to consider AOD in cases with neurological deficits or loss of consciousness in the emergency unit because earlier diagnosis could cause a wonderful improvement of the patient's prognosis.

Radiologic utility of the Gehweiler and AO spine classification systems for C1 Trauma: A retrospective review from a Level I trauma center

Objective

The purpose of our study was to identify adult trauma patients with an acute C1 burst fracture, evaluate for concomitant transverse atlantal ligament (TAL) injury, and apply the modified Gehweiler and AO spine classification systems to determine the utility of these classification systems in accurately defining C1 trauma.

Materials and Methods

Adult trauma patients with an acute C1 fracture were identified retrospectively using Nuance mPower software. The C1 fracture was described based on whether the fracture involved the anterior arch, posterior arch, lateral mass, medial tubercle, and/or transverse process. If follow-up cervical magnetic resonance imaging (MRI) was performed, the presence and location of an associated TAL injury was recorded. The anatomic location of the C1 burst fracture and TAL injury, if present, were compared with the descriptive classification systems outlined by Gehweiler/Dickman (modified) and the AO Spine society. Any additional osseous trauma of the skull base and C1-C2 was also recorded along with relevant clinical history and management.

Results

Thirty-nine patients were identified with an acute C1 burst fracture on cervical computed tomography (CT) with seventy-seven percent of patients undergoing follow-up cervical MRI. Observed fracture patterns were divided into five distinct types based on CT findings and further subdivided based on the integrity of the transverse altantal ligament on MRI. TAL tears were observed exclusively in type 3 fractures (anterior and posterior arch fractures) and type 4 fractures (anterior arch, posterior arch, and lateral mass fractures). The modified Gehweiler classification system failed to accurately describe the anatomic location of the C1 fracture in forty-four percent of patients, whereas the AO spine was too broad and failed to accurately describe fracture location in our cohort.

Conclusions

The Gehweiler and AO spine classifications demonstrated significant shortcomings in the accurate description of patients with C1 trauma. Whereas the Gehweiler system did not accurately describe the anatomic location of the various C1 fractures, the AO spine system was too broad and failed to radiologically classify fracture location. Moreover, there was a high number of patients with AO spine type B injuries without atlantoaxial translation that nevertheless required C1-C2 fusion for atlantoaxial instability. We suggest the need for an updated classification system that takes into account both the CT (fracture location) and MRI (TAL integrity) appearance of C1 trauma. An updated classification strategy will offer a radiologic standardization of C1 trauma that will aid in future research studies and help optimize patient management.

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.

Odontoid Fractures: A Standard Review of Current Concepts and Treatment Recommendations

Odontoid fractures represent the most common fractures involving C2 and the most common cervical spine fractures in patients older than 65 years. Despite their increasing frequency, optimal management of these injuries remain a subject to debate. Although types I and III injuries have relatively good healing potential with nonsurgical treatment, type II fractures carry a higher risk for nonunion. In particular, elderly patients are at risk for nonunion or fibrous malunion after nonsurgical treatment; however, increased medical comorbidities and poor bone quality also increase the risks of surgery in this cohort. The high morbidity and mortality associated with these injuries has made it an area of particular interest among spine surgeons. The purpose of this review was to summarize the pathophysiology, evaluation, and diagnosis of these injuries and to review controversies in management and considerations for treatment based on the most recent available literature.

Atlanto-occipital dislocation in a child: a challenging diagnosis. Illustrative case

BACKGROUND

Atlanto-occipital dislocation (AOD) is a highly unstable injury of the osseoligamentous complex at the craniocervical junction that is more common in children. Its diagnosis remains a challenging process that must integrate clinical presentation and radiological criteria.

OBSERVATIONS

A 9-year-old child presented with severe craniocervical trauma (Glasgow Coma Scale score 6) and cardiorespiratory arrest on-site. Prompt resuscitation on-site and transfer to the university hospital were performed, and a computed tomography (CT) scan showed a subarachnoid hemorrhage around the brainstem and a retroclival hematoma. Most of the radiological criteria on CT scans for AOD were negative, except for the occipital condyle–C1 interval, and further imaging with magnetic resonance imaging permitted the diagnosis of AOD with rupture of both the tectorial membrane and the transverse ligament. Occipital-cervical Oc-C1–2 fixation was performed. The neurological outcome was excellent, with full recovery 6 months after the trauma.

LESSONS

AOD should be suspected in all high-intensity trauma in children, especially if the clinical presentation includes cardiorespiratory arrest and other brainstem and/or upper cervical cord symptoms along with premedullary subarachnoid hemorrhage. Understanding the ligamentous nature of the injury resulting in “normal” radiographs or CT scans is important to avoid underdiagnosing AOD, which can have detrimental consequences.

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.

EuroQol-5 dimensions health-related quality of life questionnaire in craniovertebral instability treated with posterior fixation with or without occipital plating: A comparative study with matched datasets

Objective:

Methods:

Results:

Conclusions:

Cervical Myelopathy Caused by Posttraumatic Osteophytes Resulting From Long-Standing Neglected Posterior Atlanto-Occipital Dislocation More Than 30 years: A Case Report

Traumatic atlanto-occipital dislocation (AOD) is a rare but usually fatal injury. To our knowledge, no study has reported long-standing neglected posterior AOD more than 30 years in a patient who survived and later experienced cervical myelopathy.

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.

Pharyngeal perforation: A rare complication of occipitocervical injury

Background

Atlantoaxial dislocation is a rare injury following high-energy trauma. We report an undescribed complication of atlantoaxial dislocation.

Case Description

A 75-year-old man presented with atlantoaxial dislocation and Jefferson C1 fracture after a high-energy trauma. Occipitoaxial stabilizations were performed the day after. A nasopharyngeal fistula was identified at day 5 causing a persistent epistaxis.

Conclusion

Nasopharyngeal fistulization of C1 bony fragment is a rare complication of complex occipitocervical injury. Combined treatment with ENT surgeon should be considered.

Traumatic Posterior Atlanto-occipital Dislocation With Three-part Jefferson Fracture and Subaxial Distractive Extension Injury

No previous reports have described combined upper and lower cervical injuries caused by a contrary injury mechanism. A 44-year-old man was transferred complaining of quadriplegia caused by a rear-end collision car accident. CT and MRI findings revealed posterior atlanto-occipital dislocation (AOD) with three-part Jefferson fracture and subaxial distractive extension (DE) injury at the C3-4 and C6-7 levels. MRI showed spinal cord injury at C3-4 and C6-7, which caused quadriplegia and respiratory failure. When the patient arrived at the emergency department, he was already intubated because of respiratory failure. The patient was also hemodynamically unstable after lung injury and pelvic bone fracture. The patient died 1 day after the accident before undergoing surgical intervention. To the best of our knowledge, this is the first report of a case of a traumatic posterior AOD with three-part Jefferson fracture and subaxial DE injury caused by a contrary injury mechanism. Subaxial DE injury, not posterior AOD, caused fatal situation in this case. High index of suspicion and careful radiologic examination are needed to investigate the presence of associated lower cervical spine injury caused by a contrary injury mechanism in traumatic posterior AOD, which may affect treatment, outcome, and prognosis.

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.

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.

Upper Cervical Spine Trauma: WFNS Spine Committee Recommendations

Craniovertebral junction (CVJ) trauma is a challenging clinical condition. Being a highly mobile functional unit at the junction of the skull and the vertebral column, traumatic events in this area may produce devastating neurological complications and death. Additionally, many of the CVJ traumatic injuries can be left undiagnosed or even raise difficult treatment dilemmas. We present a literature review in the format of recommendations on the diagnosis and management of different scenarios for upper cervical trauma and produce recommendations, which can be applicable to various areas of the globe.

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.

Management of post-traumatic craniovertebral junction dislocation: A PRISMA-compliant systematic review and meta-analysis of casereports

Although historically considered fatal, with the advent of improved pre-hospital care, traumatic dislocation of the craniovertebral junction (CVJ) has been increasing in prevalence in neurosurgical centers. As more survivors are reported each year, a timely review with meta-analysis of their management seems necessary. PRISMA checklist was followed step by step. PubMed and Web of Science databases were searched using words “craniovertebral junction dislocation” and their corresponding synonyms. Study eligibility criteria included research studies from 2015 onwards that delineated adult and pediatric patients with confirmed post-traumatic atlantooccipital dislocation (AOD) or atlantoaxial dislocation (AAD) who survived until proper treatment. Of 1475 initial records, 46 articles met eligibility criteria with a total of 141 patients with traumatic CVJ dislocation. Of the patients, 90 were male (63.8%). Mean age of the cohort was 33.3 years (range 1–99 years). Trauma that most often led to this injury was road traffic accident (70.9%) followed by falls (24.6%). The majority of authors support posterior instrumentation of C1-C2 (45.2%) especially by means of Goel-Harms method. At mean follow-up of 15.4 months (range 0.5–60 months), 27.2% of treated patients remained neurologically intact. Of initially symptomatic, 59% improved, 37% were stable, and 4% deteriorated. Instrumenting the occiput in cases of pure AAD was associated with lower chance of neurological improvement in chi-square test (p = 0.0013) as well as in multiple linear regression (β = − 0.3; p = 0.023). The Goel-Harms C1-C2 fusion is currently the most frequently employed treatment. Many survivors remain with no deficits or improve, rarely deteriorate. Involving the occiput in stabilization in cases of AAD without AOD might be related with worse neurological prognosis.

Atlanto-occipital Dissociation in the Setting of Relatively Normal Radiologic Findings

BACKGROUND

Craniocervical junction (CCJ) dislocations are often fatal. Atlanto-occipital dissociation can be challenging to diagnose, especially in patients who present with absent or subtle radiologic signs.

CASE DESCRIPTION

A neurologically intact 37-year-old patient presented to the hospital following a high-speed motor vehicle accident. Initial computed tomography scans showed normal CCJ anatomy, but magnetic resonance imaging (MRI) of the CCJ was performed to further evaluate perimesencephalic subarachnoid hemorrhage. MRI revealed partial disruption of the anterior atlantoaxial membrane and tectorial membrane as well as complete disruption of the posterior atlanto-occipital membrane, ligamentum flavum, and apical ligament, signifying atlanto-occipital dissociation. Halo spinal immobilization was performed in preparation for stabilization with posterior occipitocervical fusion; however, the CCJ distracted widely during surgery owing to the accident-related dislocation, signifying an unstable fracture. Posterolateral fusion was performed, and the distraction injury was corrected via posterior surgical instrumentation.

CONCLUSIONS

Normal occiput-C1 craniometric parameters in the setting of unexplained perimesencephalic subarachnoid hemorrhage does not eliminate the possibility of missed or delayed diagnosis of traumatic atlanto-occipital dissociation injuries. Cervical MRI without contrast should be considered in patients with vertebral artery dissection or perimesencephalic subarachnoid hemorrhage after a blunt injury with neck pain. When MRI shows evidence of disruption of ≥2 atlanto-occipital ligaments, surgical stabilization should be considered, as these are clinically very unstable injuries.

Posterior Occipitocervical Fusion for Unstable Upper Cervical Trauma in Old and Elderly Population, Although Decreases Upper Cervical Rotation, Does Not Significantly Increase Neck Disability Index

Background

Despite the research progress in the thoraco-lumbo-pelvic balance, cervical spine balance has only recently gained increasing interest. To our knowledge, there is a lack of research regarding sagittal occipitocervical spine balance restoration following posterior occipitocervical fusion (POCF).

Purpose

The primary outcome measure is the evaluation of sagittal cervical alignment roentgenographic parameters and the secondary is the functional outcome (NDI), following POCF for upper (C1 & C2) cervical trauma (UCT) in coexistence with upper cervical spine degeneration. Patients and Methods. Twenty old and elderly patients aged 62 ± 12 years with evident upper cervical degeneration, who received POCF for upper C1 & C2 unstable cervical spine injuries, were included. C2-C7 lordosis, C2-C7 SVA, spinocranial angle (SCA), T1-slope, neck tilt (NT), thorax inlet angle (TIA), cervical tilt (CT), cranial tilt (CrT), and C0-C1 angle were measured. The subfusion angle was used to study the behavior of the unfused cervical segments below fusion. The Neck Disability Index (NDI) was used for the functional outcome evaluation. 29 age-matched individuals were used as controls for radiographic analysis and self-reported functional status comparison.

Results

The roentgenographic data were measured 3 and 39 ± 12 months postoperatively. Twelve patients showed no disability, and eight showed mild disability. Postoperatively, the patients stood with less C2-C7 lordosis, SCA, and CT (P < 0.02) but with higher NT (P < 0.02) in comparison to the controls. The patient's neck disability (NDI) was increasing as TIA increases (P=0.023). Subfusion angle seems to adapt to C2-C7 lordosis (P < 0.0033) and C0-C2 angle (P < 0.003) without any changes till the last evaluation.

Conclusions

POCF sufficiently restored occipitocervical sagittal balance along with functional outcome similar to controls in adult and elderly individuals with evident upper cervical degeneration. We do not recommend POCF for young active individuals without occipitocervical pathology, but in contrary, we recommend the removal of the spinocranial connection hardware after cervical fusion is completed.

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.

Integrity of the tectorial membrane is a favorable prognostic factor in atlanto-occipital dislocation

Objective: Atlanto-occipital dislocation is usually considered to be a fatal injury or one that leaves the victim with serious neurological deficits. The aim of this study is to illustrate a novel positive prognostic factor for atlanto-occipital dislocation, based on cervical MRI studies of patients who suffered this injury.Methods: Over the course of the past year, the authors have treated three consecutive patients with atlanto-occipital dislocation who attained an excellent clinical outcome. We retrospectively evaluated clinical, surgical and radiographic parameters in search of a common denominator to explain the excellent outcome of these patients.Results: All patients presented with severe polytrauma that required urgent surgical intervention including two laparotomies and a thoracotomy. The patients were subsequently treated with an occipitocervical fusion. No patient developed neurological deficits on long-term follow-up. The cervical MRI studies of all patients were notable for a having a preserved tectorial membrane, while other primary stabilizers of the craniocervical junction such as the apical, alar and cruciate ligaments were shown to be severely disrupted. We consider this anatomical distinction to account for their benign clinical course.Conclusion: A preserved tectorial membrane appears to be an important favorable prognostic factor in atlanto-occipital dislocation and may serve to mitigate neurological outcome in such injuries. To determine the integrity of the ligament and consequently affect clinical management, expeditious MRI of the cranio-cervical junction should be considered routinely in such injuries in addition to cervical CT scans.

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 posterior atlantooccipital dislocation with Jefferson and occipital condyle fractures: A case report

RATIONALE

To the best of our knowledge, this is the first report on a case of a traumatic posterior atlantooccipital dislocation (AOD) with 3-part Jefferson and occipital condyle fractures.

PATIENT CONCERNS

We report the case of a 60-year-old male with posterior AOD with 3-part Jefferson fracture and fracture of right occipital condyle. This injury occurred as a result of rolling down from a mountain. The patient complained of severe neck pain showing bony tenderness and ecchymosis in the high cervical area but did not show any neurologic abnormalities.

DIAGNOSES

Reconstructed computed tomography scans clearly demonstrated a 3-part Jefferson fracture and fracture of right occipital condyle, and posteriorly displaced occiput with respect to the anterior arch of C1 and dens of C2.

INTERVENTION

We planned to perform occipitocervical fusion; however, the patient refused treatment. He was transferred to another hospital and lost to follow-up.

OUTCOMES

Although extremely rare, patient who had posterior AOD with 3-part Jefferson and occipital condyle fractures can survive without neurological compromise, as was observed in our patient.

LESSONS

Clinical suspicion with thorough radiographic and physical examinations are very important for diagnosing of the upper cervical spine injuries such as AOD with Jefferson and occipital condyle fractures.

Independent predictors of survival after traumatic atlanto-occipital dissociation

BACKGROUND

Atlanto-occipital dissociation (AOD) occurs when the skull base is forcibly separated from the vertebral column. Existing literature on AOD is sparse and risk factors for mortality are unknown. This study determined independent predictors of survival after AOD.

METHODS

Patients who sustained AOD were identified from the National Trauma Data Bank (2007-2014). Those arriving without signs of life or with missing mortality data were excluded. Study groups were defined as patients who survived to hospital discharge versus patients who died in hospital. Demographics, injury data, interventions, and outcomes were compared between groups using univariate analysis. Multivariate logistic regression was used to determine independent predictors of survival.

RESULTS

After applying exclusion criteria, 1,489 patients (<1% of National Trauma Data Bank) were identified. Median age was 37 years (interquartile range [IQR), 20-59 years], and 59% of patients were male. Atlanto-occipital dissociation occurred almost exclusively after blunt mechanisms (97%), most commonly motor vehicle collisions (66%). Median injury severity score (ISS) was 25 (IQR, 10-36), with 22% mortality. Median time to death was 1,358 minutes (IQR, 281-4,451 minutes), approximately 23 hours. Independent predictors of survival were higher Glasgow Coma Scale score on admission (p < 0.001), lower ISS (p = 0.011), lower Abbreviated Injury Scale score for the head (p = 0.001), and the lack of need for exploratory laparotomy (p < 0.001). Time to neurosurgical intervention of the spine was not predictive of survival (p > 0.05). Patients who survived had a median hospital length of stay of 5 days (IQR, 1-14 days) and intensive care unit length of stay of 1 day (IQR, 0-7 days). The most common discharge destination was home (n = 393 [34%]).

CONCLUSIONS

Traumatic AOD is not uniformly fatal, with 78% of patients who arrive alive to hospital surviving to discharge. When death occurs, it is typically within the first 23 hours. Lower ISS and higher Glasgow Coma Scale score on admission independently predict survival, while time to neurosurgical intervention does not. Survivors have a short hospital stay and are commonly discharged home. This study suggests that AOD among patients who arrive alive to hospital may not be as devastating as previously considered.

LEVEL OF EVIDENCE

Progonostic/Epidemiological, level III; Therapeutic, level IV.

Occipitocervical Dislocation in Low-Energy Trauma

Traumatic occipitocervical dislocation (OCD) is described in the literature as a potentially fatal injury secondary to high-energy trauma. We describe a case of OCD occurring in a patient who sustained a ground-level fall whose only clinical symptom was posterior neck pain without neurologic compromise. Computed tomography (CT) and magnetic resonance imaging (MRI) were used to diagnose severe injury to the structurally important ligamentous complex that stabilizes the base of the skull to the spine, along with unstable fractures of the occipital condyle and C1. Emergent surgical instrumentation and fusion of occiput-C2 was performed. Postoperatively, neurologic integrity was maintained. This case illustrates that traumatic OCD is not exclusively secondary to high-energy mechanisms. It also demonstrates that severe neck pain as the only clinical manifestation in a patient with head or neck low-energy trauma is suggestive of a possible OCD. We highlight the importance of the use of head and neck CT as the first imaging-based diagnostic tool to aid in identifying this injury. Finally, surgical stabilization should be performed as soon as possible to minimize neurologic sequelae.

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.

Motion and dural sac compression in the upper cervical spine during the application of a cervical collar in case of unstable craniocervical junction-A study in two new cadaveric trauma models

Background

Unstable conditions of the craniocervical junction such as atlanto-occipital dislocation (AOD) or atlanto-axial instability (AAI) are severe injuries with a high risk of tetraplegia or death. Immobilization by a cervical collar to protect the patient from secondary damage is a standard procedure in trauma patients. If the application of a cervical collar to a patient with an unstable craniocervical condition may cause segmental motion and secondary injury to the spinal cord is unknown.

The aim of the current study is (i) to analyze compression on the dural sac and (ii) to determine relative motion of the cervical spine during the procedure of applying a cervical collar in case of ligamentous unstable craniocervical junction.

Methods and findings

Ligamentous AOD as well as AOD combined with ligamentous AAI was simulated in two newly developed cadaveric trauma models. Compression of the dural sac and segmental angulation in the upper cervical spine were measured on video fluoroscopy after myelography during the application of a cervical collar. Furthermore, overall three-dimensional motion of the cervical spine was measured by a motion tracking system.

In six cadavers each, the two new trauma models on AOD and AOD combined with AAI could be implemented. Mean dural sac compression was significantly increased to -1.1 mm (-1.3 to -0.7 mm) in case of AOD and -1.2 mm (-1.6 to -0.6 mm) in the combined model of AOD and AAI. Furthermore, there is a significant increased angulation at the C0/C1 level in the AOD model. Immense three-dimensional movement up to 22.9° of cervical spine flexion was documented during the procedure.

Conclusion

The current study pointed out that applying a cervical collar in general will cause immense three-dimensional movement. In case of unstable craniocervical junction, this leads to a dural sac compression and thus to possible damage to the spinal cord.

Ability of magnetic resonance imaging to accurately determine alar ligament integrity in patients with atlanto-occipital injuries

Objective:

The objective of this study is to evaluate the the reliability of magnetic resonance imaging (MRI) in diagnosing alar ligament disruption in patients with potential atlanto-occipital dissociation (AOD).

Materials and Methods:

Three-blinded readers performed retrospective review on 6 patients with intra-operative confirmed atlanto-occipital dissocation in addition to a comparison cohort of patients with other cervical injuries that did not involve the atlanto-occipital articulation. Ligament integrity was graded from 1 to 3 as described by Krakenes et al. The right and left ligaments were assessed separately. Inter-observer agreement by patient, by group (AOD vs. non-AOD), and intra-observer agreement was calculated using weighted Cohen's kappa.

Results:

Interobserver agreement of alar ligament grade for individual patients ranged from slight to fair (κ = 0.05–0.30). Interobserver agreement of alar ligament grade for each group (AOD vs. non-AOD) ranged from fair to substantial (κ = 0.37–0.66). No statistically significant difference in categorical analysis of groups (AOD vs. non-AOD) and grade (0–1 vs. 2–3) was observed. Intraobserver agreement of individual patient's alar ligament grade ranged from moderate to substantial (κ = 0.50–0.62).

Conclusion:

The use of MRI to detect upper cervical ligament injuries in AOD is imperfect. Our results show inconsistent and unsatisfactory interobserver and intraobserver reliability in evaluation of alar ligament injuries. While MRI has immense potential for detection of ligamentous injury at the craniovertebral junction, standardized algorithms for its use and interpretation need to be developed.

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.

Diagnostic Utility of Increased STIR Signal in the Posterior Atlanto-Occipital and Atlantoaxial Membrane Complex on MRI in Acute C1-C2 Fracture

BACKGROUND AND PURPOSE

Acute C1-C2 fractures are difficult to detect on MR imaging due to a paucity of associated bone marrow edema. The purpose of this study was to determine the diagnostic utility of increased STIR signal in the posterior atlanto-occipital and atlantoaxial membrane complex (PAOAAM) in the detection of acute C1-C2 fractures on MR imaging.

MATERIALS AND METHODS

Eighty-seven patients with C1-C2 fractures, 87 with no fractures, and 87 with other cervical fractures with acute injury who had both CT and MR imaging within 24 hours were included. All MR images were reviewed by 2 neuroradiologists for the presence of increased STIR signal in the PAOAAM and interspinous ligaments at other cervical levels. Sensitivity and specificity of increased signal within the PAOAAM for the presence of a C1-C2 fracture were assessed.

RESULTS

Increased PAOAAM STIR signal was seen in 81/87 patients with C1-C2 fractures, 6/87 patients with no fractures, and 51/87 patients with other cervical fractures with 93.1% sensitivity versus those with no fractures, other cervical fractures, and all controls. Specificity was 93.1% versus those with no fractures, 41.4% versus those with other cervical fractures, and 67.2% versus all controls for the detection of acute C1-C2 fractures. Isolated increased PAOAAM STIR signal without increased signal in other cervical interspinous ligaments showed 89.7% sensitivity versus all controls. Specificity was 95.3% versus those with no fractures, 83.7% versus those with other cervical fractures, and 91.4% versus all controls.

CONCLUSIONS

Increased PAOAAM signal on STIR is a highly sensitive indicator of an acute C1-C2 fracture on MR imaging. Furthermore, increased PAOAAM STIR signal as an isolated finding is highly specific for the presence of a C1-C2 fracture, making it a useful sign on MR imaging when CT is either unavailable or the findings are equivocal.

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.