Introduction Occipital condyle fractures are traumatic injuries that involve the craniocervicaljunction (CCJ) Epidemiology incidence approximately 1-3% of population with blunt craniocervical trauma often missed due to low diagnosis sensitivity of plain radiographs increased rate of diagnosis use due to increase in CT scan use Pathophysiology mechanism of injury high energy, non-penetrating trauma to the head/neck fracture patterns are dependent on the directional forces applied to the craniocervical junction Anderson and Montesano classification Type 1 = compression Type 2 = direct blow Type 3 = rotational/lateral bending Associated injuries orthopaedic manifestations cervical spinal cord injuries (31%) polytrauma medical manifestations intracranial bleeding brainstem and vascular lesions elevated ICP Prognosis High mortality rate (11%) due to associated injuries Anatomy Osteology occipital condyles are paired prominences of the occipital bone oval or bean shaped structures forming lateral aspects of the foramen magnum Joint articulations intrinsic relationship between occiput, atlas and axis to form the occipitoatlantoaxial complex or CCJ 6 main synovial articulations anterior and posterior median atlanto-odontoid joints paired occipitoatloid joints paired atlantoaxial joints Ligamentous structures intrinsic ligaments are located within the spinal canal, provide most of the ligamentous stability. They include transverse ligament primary stabilizer of atlantoaxial junction connects the posterior odontoid to the anterior atlas arch, inserting laterally on bony tubercles. paired alar ligaments connect the odontoid to the occipital condyles relatively strong and contributes to occipitalcervical stability apical ligament relatively weak midline structure runs vertically between the odontoid and foramen magnum. tectorial membrane connects the posterior body of the axis to the anterior foramen magnum and is the cephalad continuation of the PLL Neurovascular considerations proximity of the occipital condyles to: medulla oblongata vertebral arteries lower cranial nerves (CN IX - CN XII) Classification Anderson and Montesano classification of occipital condyle fractures Type I 3% • Impaction-type fracture with comminution of the occipital condyle • Due to compression between the atlanto-odontoid joint • Stable injury due to minimal fragment displacement into the foremen magnum Type II 22% • Basilar skull fracture that extends into one- or both occipital condyles • Due to a direct blow to skull • Stable injury as the alar ligament and tectorial membrane are usually preserved Type III 75% • Avulsion fracture of condyle in region of the alar ligament attachment (suspect underlying occipitocervical dissociation) • Due to forced rotation with combined lateral bending. • Has the potential to be unstable due to craniocervical disruption Harborview Classification of Craniocervical Injuries Type I • MRI shows craniocervical ligament injury • Craniocervical alignment is within 2mm of normal • <2mm of cervical distraction with traction Type II • MRI shows craniocervical ligament injury. • Craniocervical alignment is within 2mm of normal. • >2mm of cervical distraction with traction Type III • Craniocervical malalignment is greater than 2mm • >2mm of cervical distraction with traction Presentation History clinical presentation is highly variable presentation is largely dependent on associated injury (eg, head injury, brainstem injury, vascular injury) neurological deficits may be acute (63% of cases) or delayed (37% of cases) Symptoms high cervical pain reduced head/neck ROM torticollis lower cranial nerve deficits motor paresis Physical Examination lower cranial nerve deficits most commonly affect CN IX, X, and XI Imaging Radiographs recommended views AP, lateral, open-mouth AP view alternative views traction is generally not recommended findings diagnosis rarely made on plain radiographs due to superimposition of structures (maxilla, occiput) blocking view of occipital condyles open-mouth AP view may depict occiptal condyle injuries CT indications method of choice routine CT imaging in high-energy trauma patients clinical criteria: altered consciousness occipital pain and tenderness impaired CCJ motion lower cranial nerve paresis motor paresis views must include cranial-cervical junction with thin-section technique findings occiput fracture or CCJ instability MRI indications evaluation of soft-tissue craniocervical trauma fractured fragment located in the vertebral canal spinal cord or brain stem ischemia views MR angiogram may be considered with suspected vascular injury findings MRI better than CT for the assessment of associated brain and brain-stem injuries, although CT still considered standard for evaluating acute subarachnoid hemorrhage Treatment Nonoperative analgesics, cervical orthosis indications Type 1 and 2 Type 3 without overt instability modalities semi-rigid or rigid cervical collar Operative occipitocervical fusion indications Type 3 with overt instability neural compression from displaced fracture fragment associated occipital-atlantal or atlanto-axial injuries technique C0-C2/C3 occipitocervical arthrodesis using rigid segmental fixation or posterior decompression and instrumented fusion may require bone grafting or removal of boney fragments compressing neurovascular structures.