Comparison of Two Posterior Three-Point Fixation Techniques for Treating Reducible Atlantoaxial Dislocation

Posterior Reduction and Intra-Articular Cage Fusion With a C2 Nerve Root Preservation Technique for Treating Posterior Atlantoaxial Dislocation Secondary to Os Odontoideum

BACKGROUND AND OBJECTIVES

Posterior C1-C2 interlaminae compression fusion with iliac bone graft may lead to donor site complications and recurrent C1 posterior dislocation for posterior atlantoaxial dislocation (AAD) secondary to os odontoideum. C1-C2 intra-articular fusion often needs C2 nerve ganglion transection to facilitate exposing and manipulating the facet joint, leading to bleeding from the venous plexus and suboccipital numbness or pain. Therefore, this study was conducted to evaluate the outcomes of posterior C1-C2 intra-articular fusion with a C2 nerve root preservation technique in the treatment of posterior AAD secondary to os odontoideum.

METHODS

Data of the 11 patients who underwent C1-C2 posterior intra-articular fusion because of posterior AAD secondary to os odontoideum were retrospectively reviewed. Posterior reduction was performed using C1 transarch lateral mass screws and C2 pedicle screws. Intra-articular fusion was performed using a polyetheretherketone cage filled with autologous bone from the caudal edge of the C1 posterior arch and cranial edge of the C2 laminar. Outcomes were evaluated by using the Japanese Orthopaedics Association score, Neck Disability Index, and visual analog scale for neck pain. Bone fusion was evaluated by using computed tomography and 3-dimensional reconstruction.

RESULTS

The average follow-up duration was 43.9 ± 9.5 months. All patients achieved good reduction and bone fusion, without transection of the C2 nerve roots. The mean bone fusion time was 4.3 ± 1.1 months. There was no complication related to the surgical approach and instrumentation. Function of the spinal cord manifested by the Japanese Orthopaedics Association score significantly improved ( P < .05). The Neck Disability Index score and visual analog scale for neck pain markedly decreased (all P < .05).

CONCLUSION

Posterior reduction and intra-articular cage fusion with a C2 nerve root preservation technique was a promising treatment of posterior AAD secondary to os odontoideum.

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.

Characteristics of Cervical Sagittal Alignment at Different C0-C2 Correcting Angles in Fusion Treatment of Atlantoaxial Dislocations

OBJECTIVE

To explore the appropriate range of C0-C2 correction angles by analyzing cervical sagittal alignment parameters and evaluating clinical outcomes.

METHODS

The preoperative and postoperative radiographs, visual analogue scale, Japanese Orthopedic Association score, and neck disability index of 65 atlantoaxial dislocation patients were retrospectively collected. The C0-C2 angle, C2-C7 angle, and cervical sagittal vertical axis (cSVA) were measured from the radiographs, and an assessment of cervical degenerative disc disease was made. According to the 2-year postoperative C0-C2 angles, all patients were categorized into a <10° subgroup, 10°-20° subgroup, and >20° subgroups.

RESULTS

The postoperative C2-C7 angles and cSVA of the 10°-20° subgroup were significantly different from those of the <10° subgroup. The Japanese Orthopedic Association score of the 10°-20° subgroup was significantly different from those of the <10° and >20° subgroups. All patients (26/26) in the 10°-20° subgroup exhibited a cSVA 0-40 mm, 25% of patients (6/24) in the >20° subgroup exhibited a cSVA >40 mm, and 40% of patients (6/15) in the <10° subgroup showed a cSVA <0 mm. The postoperative incidence of cervical degenerative disc disease did not increase in the 10°-20° subgroup.

CONCLUSIONS

Atlantoaxial dislocation patients with different C0-C2 postoperative angles had different cervical sagittal alignments and clinical outcomes. In our study, the patients within the C0-C2 10°-20° subgroup exhibited superior clinical outcomes and cervical sagittal alignment.