Traumatic vertical atlantoaxial dislocation

Rare improperly treated traumatic vertical atlantoaxial dislocation: A case report and literature review

BACKGROUND

Because of the severity and fatal outcome of traumatic vertical atlantoaxial dislocation (AAD), most patients may die in the early post-traumatic period. The post-injury management of patients with vertical AAD has been rarely reported. Improper treatment may lead to disastrous outcome and further aggravate the neurologic symptoms.

CASE PRESENTATION

This report describes the perioperative management and outcome of a rare improperly treated patient with traumatic vertical AAD. The severe pulmonary infection of this patient prevented further surgery for vertical AAD. After placement of a halo vest, combined with effective antibiotic drug treatment, the patient's pulmonary infection was brought under control. The patient underwent atlantoaxial fusion using C1 lateral mass screws and C2 pedicle screws with the assistance of the halo vest. A computed tomography scan at 1 year follow-up indicated that the bone graft was fused and the patient was able to walk independently.

CONCLUSION

Skull traction is contraindicated in patients with traumatic vertical AAD. Application of a halo vest can be used for temporary fixation of the cervical spine and atlantoaxial fixation should be performed to maintain the stability of atlantoaxial articulation.

Transarticular Screw Fixation in the Treatment of Severe C1-C2 Dislocation: A Case Series Report

Background

To aim of the present paper was to evaluate the results of halo traction and transarticular screw fixation combined with bone autoplasty in patients with severe atlantoaxial dislocation.

Case presentation

This is a retrospective study of severe cases of atlantoaxial dislocation in nine patients (six men and three women) treated with preoperative halo traction and posterior C1–C2 transarticular screw fixation combined with bone autoplasty from June 2006 to June 2011 at the Saint Paul Hospital (Hanoi). The mean age of patients was 37.48 ± 13.753 years (range, 26–50 years). The possibility of fixing dislocation using a halo apparatus was investigated through a series of preoperative halo corrections performed within a span of 1–2 weeks. For transarticular screw fixation, two transarticular screws were used that were positioned according to the Magerl technique. For bone autoplasty, an iliac crest bone graft approximately 3 × 2 cm in size was used. The postoperative assessment of clinical improvement was performed using the neck disability index (NDI), the American Spinal Injury Association (ASIA) impairment scale, and the visual analog scale (VAS) measurement instruments, through the gradation of atlantoaxial dislocation, and via the clivoaxial angle(CAA) index and the space available for cord (SAC) index after 6 months. The image diagnosis demonstrates that all the cases of atlantoaxial dislocations are unstable and correspond to the Fielding and Hawkins type III dislocation. Eight patients underwent complete reduction using the halo fixation device. In one patient, the C1–C2 displacement was manually reduced during surgery. CT scanning revealed that the accuracy of screw placement was 94.4%. The bone fusion rate was 100% after 6 months. Based on the ASIA impairment scale, the preoperative examination of patients revealed grade C injuries in seven patients and grade D injuries in two patients. After surgery, all patients had grade D injuries. Six months after surgery, four patients had moderate self‐reported neck disability (30%–48%) and five patients reported mild disability (10%–28%); that is, the patient perception of the neck problem improved. In the postoperative phase, all patients showed an improvement in VAS pain scores and the SAC score returned to the normal range in all patients. The CAA returned to normal in only seven patients; in the other two patients, the CAA returned to a value that was close to normal (145° and 149°).

Conclusion

Through halo traction combined with transarticular screw fixation and bone autoplasty, noticeable postoperative improvements were attained based on the clinical scores for NDI, ASIA, and VAS, as well as SAC and CAA.

Atlanto-axial dislocation complicating a type II odontoid fracture. Reduction and final fixation

A case of traumatic posterolateral C1-C2 dislocation associated with odontoid fracture is reported. This is a rare case of traumatic posterolateral C1-C2 dislocation associated with odontoid fracture. Its management is discussed. A traumatic dislocation of atlanto-axial joint associated with an odontoid fracture remains a rare injury. No case of posterior dislocation has been reported so far in the literature with this type of management. The case is of a 25 year-old-man with a primary atlanto-axial posterolateral dislocation associated with a type II displaced odontoid fracture without any neurological complication. The patient underwent gentle traction during 24 hours with a halo frame. An incomplete reduction was achieved. Two days later, a complete reduction was obtained thanks to a preoperative manual traction maintained by a Mayfield (R) modified skull clamp. Anterior C1-C2 fixation was performed according to Vaccaro's technique. The patient wore a cervical collar and underwent physiotherapy during three months. To our best knowledge, this case represents the first traumatic atlanto-axial dislocation associated with an odontoid fracture which was treated through retropaharyngeal approach. This had been rendered possible thanks to the final reduction maneuver in extension.

Traumatic injuries to the craniovertebral junction: a review of rare events

The craniovertebral junction is a specific region of the spine with unique anatomical and biomechanical properties that yields a wide variety of injury patterns. Junctional traumatic fractures and/or dislocations are widely reported in clinical practice, but we could identify only a subgroup of upper cervical spine traumatic injuries with very few cases reported in the literature, and for this reason may be considered rare. In some of these cases, the absence of spinal biomechanical instability, in association with moderate clinical symptoms (neck stiffness and pain) and the difficulty in fracture identification through standard cervical radiographs, leads to a high percentage of missed injuries. In other cases, traumatic events have been commonly described only in autopsy series due to the high degree of spinal biomechanical instability. Herein, we have summarized all the relevant literature concerning this issue and also included our cases, with the aim of emphasizing prompt diagnosis and correct management. We provide a guide for correctly identifying "rare" craniovertebral junction traumatic injuries.

Trauma of the upper cervical spine: focus on vertical atlantoaxial dislocation

PURPOSE

Traumatic ligament injuries of the craniovertebral junction, either isolated or associated with bone avulsion or fracture, often lead to death. These injuries are rare and underrated but are increasingly seen in emergency departments due to the improvement in initial on-scene management of accidents. Vertical atlantoaxial dislocation (AAD) is a specific lesion that was barely reported. Based on our experience, our goal was to systematically investigate the prevalence and prognosis of traumatic vertical AAD and discuss its management.

METHODS

All cervical CT scans performed at our institution between 2006 and 2010 for cervical trauma in adults were retrospectively reviewed. Based on the measurement of lateral mass index (LMI), defined as the gap between C1 and C2 articular facets, we identified three cases of traumatic vertical AAD in 300 CT scans. Their medical records were investigated.

RESULTS

The incidence of vertical AAD was 1% in the exposed population. One case was an isolated vertical AAD and two were associated with a type II odontoid fracture. We report the first case in the literature of unilateral vertical AAD. Two patients died rapidly; the survivor was treated with occipitocervical fixation. Specific maneuvers were used for immobilization and reduction.

CONCLUSIONS

This study found a not insignificant incidence of vertical AAD and a high lethality rate. LMI appears to be a relevant radiological criterion for this diagnosis, for which traction is contraindicated. Associated neurological or vascular damage should be suspected and investigated. In our experience, spinal surgical fixation is required because of major instability.

Lateral C1-C2 dislocation complicating a type II odontoid fracture

We describe a unique C1-C2 lateral dislocation complicating a displaced type II odontoid fracture. We report a 63-year-old female pedestrian involved in a motor vehicle accident who required posterior open reduction and segmental C1-C2 instrumentation and fusion. Radiological examination of the cervical spine demonstrated a lateral dislocation of the atlantoaxial joint with a displaced type II fracture of the odontoid, fracture of the right lateral mass of C1 and left superior articular facet of C2. Neurological examination revealed the patient to be myelopathic and closed halo traction failed to achieve reduction. Due to the irreducible nature of the dislocation, posterior open reduction and segmental C1-C2 instrumentation and fusion was performed. The dislocated C1-C2 articulation was successfully reduced surgically with subsequent bony fusion and resolution of all neurological symptoms and signs at final follow-up. To our knowledge, this the first report of this type of injury. We also review the related literature on this unique injury pattern.