A rare case of atlantooccipital dissociation in the context of occipitalization of the atlas, with a 2-year follow-up

Abstract

<jats:p>Atlantooccipital dislocation (AOD) is a rare and often fatal injury. In cases of survival, residual deficits are severe and often include cranial nerve palsy, quadriplegia, or respiratory issues. Occipitalization is defined as partial or complete congenital fusion of the occiput to the atlas and is exceptionally rare.</jats:p> <jats:p>The authors present a rare case of AOD superimposed on a congenital occipitalization of the atlas. This 39-year-old man had AOD following a motor vehicle collision. On examination, his overall motor score on the American Spinal Injury Association scale was 5/100, and his rectal tone was absent. Computed tomography demonstrated AOD in an area of occipitalization. Magnetic resonance imaging revealed ligamentous injury leading to C1–2 instability.</jats:p> <jats:p>Intervention included occipital cervical instrumentation fusion from the occiput to C-3. Six months postoperatively, imaging revealed fusion of the graft and consolidation of the fractured occipitalization. At the 2-year follow-up, the patient's strength was 3/5 for wrist extension and handgrip on the right side and full strength in the rest of the myotomes. Bladder and bowel function was also normalized.</jats:p> <jats:p>A high-velocity collision led to disruption of the atlantooccipital ligaments and fracture of the occipitalized lateral masses in this patient. Internal fixation and fusion led to good fusion postoperatively. Occipitalization probably led to abnormal joint mechanics at the C1-occiput junction, which might have altered the amount of force required to fracture the occipitalization and produce AOD. This difference may partially account for the favorable neurological outcome in the featured patient compared with traditional cases of AOD.</jats:p>

The Application of the Revised Condyle–C1 Interval Method to Diagnose Traumatic Atlanto-occipital Dissociation in Adults

“…2 , 3 , 4 In the recent years, reports indicting favorable outcomes have emerged reflecting improvements in the emergency management, transport, and, most importantly, recognition of this injury. 5 , 6 , 7 , 8…”

Traumatic posterior atlantooccipital dislocation with Jefferson and occipital condyle fractures

“…This case reports a traumatic AOD and its association with Jefferson and occipital condyle fractures. [7–12] AOD is commonly associated with upper cervical injuries, [3,9] which occurs as an isolated injury or as a combined trauma. Traumatic AOD results from an injury of ligamentous structures to the craniocervical junction and is associated with a high rate of mortality and severe neurological deficits.…”

Clival Screw Placement in Patient with atlas assimilation: A CT-based feasibility study

“…The C1A is commonly associated with basilar invagination and atlantoaxial dislocation, and makes the odontoid process compress the cervicomedullary 6 and requires a surgical interventionton to stabilize the occipitocervical junction, to correct the deformity and decompress the neural structures 7 8 . Occipitocervical fixation spanning from occiput to C2 has been used to treat the instability of occipitocervical junction 9 10 11 12 . However, C1 and C2 screw placement is more difficult and dangerous in C1A patients.…”

“…To successfully stabilize the mechanically compromised occipitocervical junction, one must surgically correct deformity and decompress the neural structures. Occipitocervical fixation was widely used in disorders related with instability of the occipitocervical junciton 9 10 11 12 . Alternatively, anterior occipitocervical fusion using the clivus as the cephalad anchoring point was reported in several studies 13 14 15 .…”