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

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.

Cervical MRI assessment of traumatic anterior atlanto-occipital membrane complex injuries with evaluation of ancillary findings

BACKGROUND AND PURPOSE

The purpose of this study was to identify and classify the different types of anterior atlanto-occipital membrane complex injuries on MRI and evaluate for the presence, size, and location of a prevertebral effusion on the preceding CT exams.

MATERIALS AND METHODS

Patients who suffered an anterior atlanto-occipital membrane complex injury were identified retrospectively utilizing Nuance mPower software. An anatomic-based description of the location of the anterior atlanto-occipital membrane complex injury was recorded along with any additional osteoligamentous trauma of the craniocervical junction. The preceding cervical CT exams for these patients were reviewed for the presence and location of a prevertebral effusion.

RESULTS

Fifty patients were identified with an acute, post-traumatic anterior atlanto-occipital membrane complex injury. Three distinct patterns of anterior atlanto-occipital membrane complex injury were observed. Nineteen patients demonstrated increased STIR signal with disruption of the anterior atlanto-occipital membrane, ten patients demonstrated increased STIR signal with disruption of the anterior atlanto-axial membrane, and twenty-one patients demonstrated increased STIR signal with disruption of both the anterior atlanto-occipital membrane and anterior atlanto-axial membrane. An effusion at the C1-C2 level was present in greater than 90% of patients with anterior atlanto-occipital membrane complex injury.

CONCLUSIONS

The presence of a craniocervical prevertebral effusion on CT in trauma patients may raise suspicion for an injury to the anterior atlanto-occipital membrane complex and potentially trigger additional investigation with cervical MRI.

Management of traumatic atlanto-occipital dislocation in a 10-year-old with noninvasive halo immobilization: A case report

Background

Traumatic atlanto-occipital dislocation is an unstable injury of the craniocervical junction. For pediatric patients, surgical arthrodesis of the occipitocervical junction is the recommended management. While having a high success rate for stabilization, the fusion comes with obvious morbidity of limitation in cervical spine flexion, extension, and rotation. An alternative is external immobilization with a conventional halo.

Case Description

We describe the case of a 10-year-old boy who was treated successfully for traumatic AOD with a noninvasive pinless halo. Following initial brain trauma management, we immobilized the craniocervical junction with a pinless halo after reducing the atlanto-occipital dislocation. The pinless halo was kept on at all times for the next 3 months. The craniocervical junction alignment was monitored with weekly cervical spine X-rays and CT craniocervical junction on day 15th, day 30th, and day 70th. A follow-up MRI C-spine 3 months from presentation confirmed resolution of the soft-tissue injury and the pinless halo was removed. Dynamic cervical spine X-rays revealed satisfactory alignment in both flexion and extension views. The patient has been followed up for 2 years postinjury and no issues were identified.

Conclusion

Noninvasive pinless halo is a potential treatment option for traumatic pediatric atlanto-occipital dislocation. This should be considered bearing in mind multiple factors including age and weight of the patient, severity of the atlanto-occipital dislocation (Grade I vs. Grade II and incomplete vs. complete), concomitant skull and scalp injury, and patient's ability to tolerate the halo. It is vital to emphasize that this necessitates close clinicoradiological monitoring.

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.

Upper Cervical Trauma

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

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

BACKGROUND

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

OBSERVATIONS

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

LESSONS

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