Paradoxical Distraction with Upright Position After Halo Fixation in 2 Patients with Atlanto-Occipital Dislocation.

BACKGROUND: Atlanto-occipital dislocation (AOD) is the most uncommon form of traumatic cervical spine injury. The majority of patients die before reaching higher-level care, and only a small percentage of patients with AOD survive the initial injury after receiving tertiary care. As such, there is a paucity of evidence-based management guidelines for treating this condition. Halo vest fixation has been a proposed method for interim stability while these patients undergo medical optimization for surgical intervention. There have been several reports of worsening AOD after halo placement. Reverse Trendelenburg position after halo fixation has been previously described to aid in the reduction of AOD, as well as concomitant atlantoaxial dislocation by gravitational downward force.

CASE DESCRIPTION: In this series we present 2 cases of obese patients (body mass index >30) with AOD treated by halo fixation that had increased distraction after head of bed elevation.

CONCLUSION: Our theorized mechanism for this phenomenon is due to the downward pull of subaxial forces secondary to a large body habitus.