Traumatic Atlanto-Occipital Dislocation-A Comprehensive Analysis of All Case Series Found in the Spinal Trauma Literature

Abstract

Background: Traumatic atlanto-occipital dislocation (TAOD) is one of the most devastating traumatic injuries, generally associated with immediate death after high-energy trauma. The aim of this study was to perform a systematic literature review of all cases series of TAOD and present the current state of this entity.

Methods: A systematic literature review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Only case series with at least 5 cases were included in the analysis. We focused on survival rates, diagnostic methods, delays in diagnosis, outcomes, and cases successfully treated nonoperatively.

Results: A total of 17 articles were included (16 retrospective and 1 prospective study) with 341 patients. Six studies included pediatric patients only. The mean Glasgow Coma Scale at admission was ≤8 in all studies. Many different diagnostic criteria were used, but none of them had high accuracy. The overall mortality rate was 34.8%, but the studies' designs were heterogeneous (some included only survivors). A high rate of concomitant traumatic brain injury was documented in some studies. We found it interesting that some patients were treated with cervical immobilization (37/341; 10.8%), which was generally used in less unstable injuries; however, the majority of patients were managed with an occipito-cervical fusion (193/341; 56.5%).

Conclusions: TAOD is a devastating traumatic injury, with a high mortality rate. An MRI may be recommended when there are subtle findings of TAOD and a normal computed tomography scan, such as subarachnoid hemorrhage in the posterior fossa, upper cervical injuries, or consistent neurological findings. Further studies are necessary to identify patients with mild MRI findings and TAOD that may be managed nonoperatively.

Keywords: atlanto-occipital dislocation; craniocervical dislocation; injury; occipito-cervical dislocation; traumatic.

Figure 1

Flowchart diagram of our search mechanism in accordance to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

Figure 2

Sagittal midline computed tomography (CT) scan measuring the distance from the basion to the tip of the dens—the basion-dens interval. Normal values from adults' CT scans are <8.5 mm in 95% of the cases.

Figure 3

(A) Sagittal and (B) coronal computed tomography (CT) scan reconstructions—4 equidistant points were marked on the articulating surfaces of the occiput-C1 joint that encompassed the broadest joint surface. The joint interval at each point was recorded and the mean of these 8 measurements (from both sides and from sagittal and coronal CT scans) are the true condyle-C1 interval (CCI).

Figure 4

Sagittal CT scan (A) of a normal and (B) of a patient with a traumatic atlanto-occipital dislocation (TAOD). The red line in B represents the revised condyle-C1 interval (CCI). The diagnosis of TAOD is made when distance at the point of great separation of the C1 lateral mass from the occipital condyle is greater than 2.5 mm.