Unique paradoxical atlantoaxial dislocation with C1-C2 facet diastases and isolated ligamentous injury to the craniovertebral junction without neurological deficits: A case report
This 32-year-old gentleman was involved in a high speed car accident without a fastened seatbelt. He survived a whiplash injury, lost consciousness, and sustained severe facial injuries with soft tissue swelling. On examination he had stridor, airway compromise, and hypoxia for which he underwent an emergency tracheostomy. He had no neurological deficits. He had a fractured mandible and his neck was tilted to the right with chin to the left.\nHis X-ray cervical spine showed a displaced odontoid, anterior to the anterior arch of atlas. Computed tomography (CT) scan of the CVJ showed a dislocated odontoid, anterior to C1 arch in front of right lateral mass of atlas []. The C1-C2 facets were seen diastased bilaterally []. Magnetic resonance imaging (MRI) of CVJ [] showed disrupted posterior longitudinal ligament with severe kinking of the spinal cord. TAL was seen intact on T2 axial MRI. MR angiography showed a flow cutoff in the left vertebral artery at the level of C2-C3 and a thin streak of flow was noted in the right vertebral artery at the level of CVJ [].\nHe underwent an awake reduction of the dislocation in the OR. Using Gardner-Wells skull traction, slow distraction with gradual rotation to the left was applied. A continuous fluoroscopy revealed progressive realignment of the odontoid []. This also corrected the neck tilt. He was awake when positioned prone and after confirming the position of odontoid and intact neurological status, he underwent C1 lateral mass and C2 pedicle screw fixation with fusion across the C1-C2 joint. The joint capsule was torn with a large gap between C1 and C2 facets. It was filled with bone graft after debridement to facilitate fusion. The vertebral arteries were looking perfectly normal and were seen positioned normal in relation to the CVJ.\nHe had quadriparesis in the immediate postoperative period. It was predominantly proximal in involvement and was symmetrical. CT scan of the CVJ revealed normal alignment of atlas and axis and implants in situ []. MRI of the CVJ revealed normal spinal cord with normal alignment. MRA of the vertebral artery showed occlusion of the right vertebral artery beginning at the origin and extending up to the origin of the basilar artery intracranially, suggesting complete thrombosis secondary to a possible traumatic dissection. The possibility of worsening secondary to surgical manipulation could not be ruled out. However, the left vertebral flow pattern was the same as preoperative MRA with segmental loss of flow at the distal V1 segment []. The patient was treated with anticoagulants and he made gradual recovery without any deficits at 2 weeks after surgery. He was able to go back to work after 3 months and neurologically intact at 1 year after surgery. Repeat CT scan showed good alignment of implants.