Diagnosis and management of traumatic atlanto-occipital dislocation injuries

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.

Pediatric Spine Trauma

Pediatric spine has growth potential with incomplete ossification, and also unique biomechanics which have important implications for trauma patients. This article intends to review various aspects of pediatric spine trauma including epidemiology, anatomy and biomechanics, and clinically relevant details of each type of injury based on the location and mechanism of injury. With the appropriate but not superfluous treatment, pediatric spine trauma patients can have better chance of recovery. Therefore, as a spine surgeon, understanding the general concept for each injury subtype together with the debate and progress in the field is inevitable.

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.

Development of best practices in the utilization and implementation of pediatric cervical spine traction: a modified Delphi study

OBJECTIVE

Cervical traction in pediatric patients is an uncommon but invaluable technique in the management of cervical trauma and deformity. Despite its utility, little empirical evidence exists to guide its implementation, with most practitioners employing custom or modified adult protocols. Expert-based best practices may improve the care of children undergoing cervical traction. In this study, the authors aimed to build consensus and establish best practices for the use of pediatric cervical traction in order to enhance its utilization, safety, and efficacy.

METHODS

A modified Delphi method was employed to try to identify areas of consensus regarding the utilization and implementation of pediatric cervical spine traction. A literature review of pediatric cervical traction was distributed electronically along with a survey of current practices to a group of 20 board-certified pediatric neurosurgeons and orthopedic surgeons with expertise in the pediatric cervical spine. Sixty statements were then formulated and distributed to the group. The results of the second survey were discussed during an in-person meeting leading to further consensus. Consensus was defined as ≥ 80% agreement on a 4-point Likert scale (strongly agree, agree, disagree, strongly disagree).

RESULTS

After the initial round, consensus was achieved with 40 statements regarding the following topics: goals, indications, and contraindications of traction (12), pretraction imaging (6), practical application and initiation of various traction techniques (8), protocols in trauma and deformity patients (8), and management of traction-related complications (6). Following the second round, an additional 9 statements reached consensus related to goals/indications/contraindications of traction (4), related to initiation of traction (4), and related to complication management (1). All participants were willing to incorporate the consensus statements into their practice.

CONCLUSIONS

In an attempt to improve and standardize the use of cervical traction in pediatric patients, the authors have identified 49 best-practice recommendations, which were generated by reaching consensus among a multidisciplinary group of pediatric spine experts using a modified Delphi technique. Further study is required to determine if implementation of these practices can lead to reduced complications and improved outcomes for children.

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.

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.

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.

Early Identification of Traumatic Durotomy Associated with Atlantooccipital Dislocation May Prevent Retropharyngeal Pseudomeningocele Development

Atlantooccipital dislocation can be complicated by a traumatic durotomy that may lead to the rare development of a retropharyngeal pseudomeningocele. To our knowledge this has been reported only five times previously. We present the case of a 60-year-old man involved in a motor vehicle accident who suffered an atlantooccipital dislocation and C5-C6 three-column injury. A unique MRI image of a defect in the ventral dura posterior to C2 was appreciated. He underwent occiput to T2 internal fixation and arthrodesis. During surgery, CSF egress was seen caudal to the right C2 nerve root. A DuraMatrix onlay patch reinforced with DuraSeal was placed to stop the CSF leak. A lumbar subarachnoid drain was also placed. The patient made a satisfactory recovery with residual mild weakness of his right upper extremity. In this report, we demonstrate that careful MRI review can reveal a ventral durotomy in a traumatic atlantooccipital dislocation and, if discovered, effective treatment including a lumbar subarachnoid drain for CSF diversion may prevent progression to a retropharyngeal pseudomeningocele. The literature on this rare presentation and associated durotomy is provided.

Traumatic atlanto-occipital dislocation presenting with Dysphagia as the chief complaint: a case report

We report a patient with traumatic atlanto-occipital dislocation who presented with dysphagia as the chief complaint. A 59-year-old man complained of swallowing difficulty for 2 months after trauma to the neck. On physical examination, there was atrophy of the right sternocleidomastoid and upper trapezius muscles, and the tongue was deviated to the right. In a videofluoroscopic swallowing study, penetration and aspiration were not seen, food residue remained in the right vallecula and pyriform sinus, and there was decreased motion of the soft palate, pharynx and larynx. Electromyography confirmed a right spinal accessory nerve lesion. Magnetic resonance imaging confirmed atlanto-occipital dislocation. Dysphagia in atlanto-occipital dislocation is induced by medullary compression and lower cranial nerve injury. Therefore, in survivors who are diagnosed with atlanto-occipital dislocation, any neurological symptoms should be carefully evaluated.

Traumatic atlanto-occipital dislocation: a case report

We report a 30-year-old man with atlanto-occipital dislocation after a traffic accident. Diagnosis was based on radiography, computed tomography, and magnetic resonance imaging. Owing to the critical conditions that did not fulfil advanced trauma and life support protocols, surgical treatment was deferred, and the patient died 10 hours later.

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.

Inception of an Australian spine trauma registry: the minimum dataset

Background The establishment of a spine trauma registry collecting both spine column and spinal cord data should improve the evidential basis for clinical decisions. This is a report on the pilot of a spine trauma registry including development of a minimum dataset. Methods A minimum dataset consisting of 56 data items was created using the modified Delphi technique. A pilot study was performed on 104 consecutive spine trauma patients recruited by the Victorian Orthopaedic Trauma Outcomes Registry (VOTOR). Data analysis and collection methodology were reviewed to determine its feasibility. Results Minimum dataset collection aided by a dataset dictionary was uncomplicated (average of 5 minutes per patient). Data analysis revealed three significant findings: (1) a peak in the 40 to 60 years age group; (2) premorbid functional independence in the majority of patients; and (3) significant proportion being on antiplatelet or anticoagulation medications. Of the 141 traumatic spine fractures, the thoracolumbar segment was the most frequent site of injury. Most were neurologically intact (89%). Our study group had satisfactory 6-month patient-reported outcomes. Conclusion The minimum dataset had high completion rates, was practical and feasible to collect. This pilot study is the basis for the development of a spine trauma registry at the Level 1 trauma center.

Advances in the management of spinal cord and spinal column injuries

Spinal cord injury (SCI) is a significant public problem, with recent data suggesting that over 1 million people in the U.S.A. alone are affected by paralysis resulting from SCI. Recent advances in prehospital care have improved survival as well as reduced incidence and severity of SCI following spine trauma. Furthermore, increased understanding of the secondary mechanisms of injury following SCI has provided improvements in critical care and acute management in patients suffering from SCI, thus limiting morbidity following injury. In addition, improved technology and biomechanical understanding of the mechanisms of spine trauma have allowed further advances in available techniques for spinal decompression and stabilization. In this chapter we review the most recent data and salient literature regarding SCI and address current controversies, including the use of pharmacological adjuncts in the setting of acute SCI. We will also attempt to provide a reader with basic understanding of the classifications of SCI and spinal column injury. Finally, we review advances in spinal column stabilization including improvements in instrumented fusion and minimally invasive surgery.

Radiographic analysis of type II odontoid fractures in a geriatric patient population: description and pathomechanism of the "Geier"-deformity

INTRODUCTION

Type II odontoid fractures are one among the most common cervical spine fractures in the elders. We reviewed a consecutive series of patients, aged 65 years and older, presenting to our institution with type II odontoid fractures. Our analysis focused on the radiographic outcome, union rate and the development of cervical spine postural deformity.

PATIENTS/METHODS

Indications for surgical treatment (OP) included displaced or unstable injuries. Stable, non-displaced injuries or patients with significant co-morbidities were treated nonoperatively (non-op).

RESULTS

Ninety patients (50 f, 40 m) with an average age of 83 years (65-101) were identified. 31 (34.4%) patients were received OP and 57 (63.3%) were received non-op treatments. The hospital length of stay was significantly longer after OP (mean 10 days vs. 6 days non-op) treatment (p = 0.007). At follow-up, higher union rates were noted in the OP (76.2%) than in the non-op group (58.3%).

CONCLUSION

We observed a characteristic cervical spine deformity in geriatric patients with type II odontoid fractures, and have termed this the "Geier-deformity". Clinical findings of the deformity include sagittal imbalance and kyphosis of the lower cervical spine.

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.

SURGICAL TREATMENT OF OCCIPITOCERVICAL INSTABILITY

OBJECTIVE

Instability of the occipitocervical junction can be a challenging surgical problem because of the unique anatomic and biomechanical characteristics of this region. We review the causes of instability and the development of surgical techniques to stabilize the occipitocervical junction.

METHODS

Occipitocervical instrumentation has advanced significantly, and modern modular screw-based constructs allow for rigid short-segment fixation of unstable elements while providing the stability needed to achieve successful fusion in nearly 100% of patients. This article reviews the preoperative planning, the variety of instrumentation and surgical strategies, as well as the postoperative care of these patients.

RESULTS

Current constructs use occipital plates that are rigidly fixed to the thick midline keel of the occipital bone, polyaxial screws that can be placed in many different trajectories, and rods that are bent to approximate the acute occipitocervical angle. These modular constructs provide a variety of methods to achieve fixation in the atlantoaxial complex, including transarticular screws or C1 lateral mass screws in combination with C2 pars, C2 pedicle, or C2 translaminar trajectories.

CONCLUSION

Surgical techniques for occipitocervical instrumentation and fusion are technically challenging and require meticulous preoperative planning and a thorough understanding of the regional anatomy, instrumentation, and constructs. Modern screw-based techniques for occipitocervical fusion have established clinical success and demonstrated biomechanical stability, with fusion rates approaching 100%.

Survivors of occipitoatlantal dislocation injuries: imaging and clinical correlates

OBJECT

Although rare, traumatic occipitoatlantal dislocation (OAD) injuries are associated with a high mortality rate. The authors evaluated the imaging and clinical factors that determined treatment and were predictive of outcomes, respectively, in survivors of this injury.

METHODS

The medical records and imaging studies obtained in 33 patients with OAD were reviewed retrospectively. Clinical factors that predicted outcomes, especially neurological injury at presentation and imaging findings, were evaluated. The most sensitive method for the diagnosis of OAD was the measurement of basion axial-basion dens interval on computed tomography (CT) scanning. Five patients with severe traumatic brain injuries (TBIs) were not treated and subsequently died. Of the 28 patients in whom treatment was performed, 23 underwent fusion and five were fitted with an external orthosis. Abnormal findings of the occipitoatlantal ligaments on magnetic resonance (MR) imaging, associated with no or questionable abnormalities on CT scanning, provided the rationale for nonoperative treatment. Of the 28 patients treated for their injuries, perioperative death occurred in five, three of whom had presented with severe neurological injuries. The mortality rate was highest in patients with a TBI at presentation. The mortality rate was lower in patients presenting with a spinal cord injury, but in this group there was a higher rate of persistent neurological deficits.

CONCLUSIONS

The spines in patients with CT-documented OAD are most likely unstable and need surgical fixation. In patients for whom CT findings are normal and MR imaging findings suggest marginal abnormalities, nonoperative treatment should be considered. The best predictors of outcome were severe brain or upper cervical injuries at initial presentation.

Traumatic occipitocervical disruption: a new technique for stabilisation

Traumatic atlanto-occipital dislocation in adults is usually fatal and survival without neurological deficit is rare. The surgical management of those who do survive is difficult and controversial. Most authorities recommend posterior occipitoaxial fusion, but this compromises cervical rotation. We describe a case in which a patient with a traumatic atlanto-occipital disruption but no neurological deficit was treated by atlanto-occipital fusion using a new technique consisting of cancellous bone autografting supported by an occipital plate linked by rods to lateral mass screws in the atlas. The technique is described in detail. At one year the neck was stable, radiological fusion had been achieved, and atlantoaxial rotation preserved.

The rationale behind this approach is discussed and the relevant literature reviewed. We recommend the technique for injuries of this type.

Traumatic atlanto-occipital dislocation: presentation of a new posterior occipitoatlantoaxial fixation technique in an adult survivor: technical case report

OBJECTIVE AND IMPORTANCE

More survivors of traumatic atlanto-occipital dislocation (AOD) in adults have recently been reported. Surgical management options are therefore of increasing interest. We present a new technique of posterior C0-C1-C2 fixation.

CLINICAL PRESENTATION

A 29-year-old motorcyclist survived a traumatic vertical AOD of 15 mm. No spinal cord or medullary lesion was present. Brain contusion and diffuse axonal injuries led to a cortical biplegia, which recovered progressively over a period of 6 months. Twelve months after surgery, no neurological deficit was present except for slightly increased deep tendon reflexes.

INTERVENTION

Posterior C0-C1-C2 fixation was performed with two bicortical occipital screws, one bicortical lateral mass screw in the atlas, and one monocortical pars screw in the axis on each side, connected to a plate-rod on the right and left sides. Fusion was performed with monocortical bone graft from the posterior iliac crest.

CONCLUSION

The surgical technique described was thought to be safe to perform and resulted in immediate stability without external immobilization. Solid fusion was achieved 6 months after surgery.

Complete medulla/cervical spinal cord transection after atlanto-occipital dislocation: An extraordinary case

STUDY DESIGN

Case report.

SUMMARY OF BACKGROUND DATA

Traumatic atlanto-occipital dislocation (AOD) with a complete medulla/spinal cord transection is rare and believed to be fatal owing to the high level of the spinal cord injury. Clinical outcome is poor. Consequently, relatively few case reports of adult patients surviving this injury appear in the literature. OBJECTIVES AND RESULT: We present the case of a 20-year-old male, who sustained an AOD with a complete medulla/spinal cord transection in a motorcycle accident to discuss the possibility of long-term survival with this condition. The patient underwent occipito-cervical stabilization. With an Injury Severity Score of 75, by definition unsurvivable, the patient is 16 months after the injury, ventilated and fully dependent for all care.

CONCLUSION

Long-term survival following AOD with a complete medulla/spinal cord transection is possible if immediate resuscitation at the scene is available. Nevertheless, it remains questionable whether or not a patient with such a devastating injury and without any prospect of functional recovery should be kept alive under all circumstances.

Retropharyngeal Pseudomeningocele Presenting as Dysphagia After Atlantooccipital Dislocation

EDUCATIONAL OBJECTIVE

At the conclusion of this paper, the readers should be able to recognize a retropharyngeal pseudomeningocele as a potential complication of atlanto occipital dislocation.

OBJECTIVES

To demonstrate how a retropharyngeal pseudomeningocele may present as dysphagia in a patient who is recovering from atlanto occipital dislocation as well as to discuss the treatment options in this situation.

STUDY DESIGN

Case report and literature review.

METHODS

Analysis of a case through medical record and literature review.

RESULTS

A retropharyngeal pseudomeningocele is a very rare complication of atlanto occipital dislocation. It may develop weeks after the initial injury and can present with respiratory or swallowing difficulties. Decompression via a ventriculoperitoneal or lumboperitoneal shunt facilitates resolution of the cerebral spinal fluid collection.

CONCLUSIONS

A retropharyngeal pseudomeningocele should be considered in all patients status post-atlanto occipital dislocation who are experiencing respiratory distress or dysphagia.

Traumatic atlanto-occipital dislocation with atlantoaxial subluxation

STUDY DESIGN

This is a case report of a patient who survived traumatic atlanto-occipital dislocation with atlantoaxial subluxation.

OBJECTIVE

To describe the useful points of 3-dimensional computerized tomography (CT) and magnetic resonance imaging (MRI) for an evaluation of atlanto-occipital dislocation.

SUMMARY OF BACKGROUND DATA

Atlanto-occipital dislocation is a severe ligamentous injury that usually results in either a fatal outcome or severe neurologic deficit. To our knowledge, no patient who has survived atlanto-occipital dislocation with atlantoaxial subluxation has yet been reported.

METHODS

Three-dimensional CT was performed to confirm the diagnosis of atlanto-occipital dislocation and precisely evaluate the magnitude of displacement. MRI clearly showed a disruption of the ligamentous structures, which play a role as the primary stabilizers of the cranium on the cervical spine.

RESULTS

As soon as the patient's general condition improved, the posterior spinal fusion with internal fixation was performed to maintain the stability of cervical spine. A significant degree of motor function was regained within 2 years after injury.

CONCLUSIONS

In this case, the diagnosis was accurately confirmed, and the cervical spine was evaluated in detail using both 3-dimensional CT and MRI as a reliable examination for atlanto-occipital dislocation.

Redislocation in a halo vest of an atlanto-occipital dislocation in a child: recommendations for treatment

STUDY DESIGN

A case of a child with a traumatic atlanto-occipital dislocation (AOD), with unexpected secondary redislocation in a halo vest is presented. An extensive literature review was performed.

OBJECTIVES

To show the difficulties in diagnosing AOD, to emphasize its intrinsic instability, and to make recommendations for treatment of this condition.

SUMMARY OF BACKGROUND DATA

AOD is a rare condition that is difficult to diagnose. Because of the high neurologic morbidity, this injury often results in death. Different diagnostic approaches have been evaluated throughout the literature. Also, there are different opinions on how to treat AOD. There is no large trial that compares conservative treatment with surgery.

METHODS

A 4-year-old child with a longitudinal distraction of the head is described. Because of his tenuous medical condition, initial treatment was in a halo vest. However, redislocation occurred inside the vest, so surgical stabilization was performed as soon as the patient's condition allowed.

RESULTS

To diagnose AOD, different measuring techniques can be applied on a lateral cervical spine radiograph. Using a combination of these tools, the sensitivity of the examination can be increased. There are 3 types of dislocation. Type II, which is a longitudinal distraction, is most unstable. Once confirmed, AOD should be immobilized. This can temporarily be performed with a halo-frame, but our case shows that this does not necessarily provide a stable situation, and early surgical reconstruction should be considered.

CONCLUSIONS

AOD can be an extremely unstable lesion and is difficult to diagnose. Although initial treatment in a halo vest is recommended, redislocation can occur even in the vest. We recommend urgent surgical stabilization.

A blinded assessment of radiographic criteria for atlanto-occipital dislocation

STUDY DESIGN

Blinded comparison of 5 methods to diagnose atlanto-occipital dislocation (AOD) on plain radiographs and computerized tomography (CT) of the cervical spine.

OBJECTIVE

To determine the best method to diagnose AOD.

SUMMARY OF BACKGROUND DATA

Several methods are proposed for the diagnosis of AOD, including the Power's ratio, X-line method, basion-dens interval, condylar gap, and Harris method. No blinded comparison of the results of these methods has been compared to patient outcome, and there is no information available regarding the accuracy of these methods applied to CT scans.

METHODS

Plain lateral radiographs and CTs of the cervical spine were reviewed in 104 patients, including 6 with AOD. Images underwent a blinded review by a board certified neurosurgeon (D.K.R.), orthopedist (P.A.A.), radiologist (J.C.), and emergency physician (D.B.B.). Each diagnostic method for AOD was applied for determination of sensitivity, specificity, and positive and negative predictive values. The ability to identify relevant anatomic landmarks was also tabulated.

RESULTS

Average values for sensitivities, specificities, positive and negative predictive values for each method applied to plain radiographs are: 0.4625-1.0, 0.8933-0.9725, 0.2775-0.45, and 0.975-1.0, respectively. These values for each method applied to CT scans are: 0.7075-1.0, 0.8725-0.9775, 0.3175-1, and 0.98-1.0, respectively. Identification of relevant anatomic landmarks occurred 99.75% of the time when these methods were applied to CT scans compared to 39% to 84% of the time on plain radiographs.

CONCLUSIONS

Sensitivity, specificity, positive and negative predictive values of these methods improve when applied to CT scans because of better visualization of anatomic landmarks. This result suggests CT scans of the cervical spine may be warranted in all trauma patients suspected of having cervical spine injury.