Case of the Month
Section Editor: Nicholas Stence, MD
Children's Hospital Colorado, Aurora, CO
October 2022
Next Case of the Month Coming November 8...
Craniocervical Dissociation Complicated by Prevertebral Pseudomeningocele
- Background:
- Craniocervical dissociation (CCD) is a rare and often fatal traumatic injury. Patients most commonly present following a high-speed motor vehicle accident.
- CCD occurs when there is disruption of ligamentous and/or osseous points of contact between the occiput, C1, and C2.
- This case is unique due to the development of a prevertebral pseudomeningocele related to a traumatic dural tear.
- Phase-contrast MR cineradiography may be used to confirm a CSF leak. An alternative confirmatory test, myelography, requires greater patient cooperation and presents technical challenges in critically ill patients.
- Clinical Presentation:
- When not fatal in the field, patients presenting to the trauma service with CCD are critically ill with low GCS scores.
- CSF leak related to traumatic CCD is rare, with limited case report descriptions in the literature. Given significant concomitant injuries, the typical clinical findings suggestive of CSF leak/intracranial hypotension (positional headache) would not be expected to be detectable in these patients, highlighting the importance of imaging in making this diagnosis.
- Key Diagnostic Features:
- Traumatic CCD
- Radiography/CT
- Basion-dens interval >10 mm; Powers ratio >1.0; atlanto-dental interval >3 mm
- Abnormal widening/malalignment of the atlantoaxial and/or the atlanto-occipital joints
- MRI
- Ligamentous disruption/edematous signal intensity involving the tectorial membrane; alar, apical, and cruciate ligaments; anterior and posterior atlanto-occipital membranes; and posterior atlantoaxial membrane
- Alar ligament and tectorial membrane injuries are particularly associated with poor prognosis.
- Atlanto-occipital or atlantoaxial capsule injury (widening of joints with fluid signal on MRI)
- Ligamentous disruption/edematous signal intensity involving the tectorial membrane; alar, apical, and cruciate ligaments; anterior and posterior atlanto-occipital membranes; and posterior atlantoaxial membrane
- Radiography/CT
- Traumatic dural tear/CSF leak
- CT
- An enlarging prevertebral fluid collection in the postoperative or posttraumatic setting is unexpected and should raise suspicion for underlying pathology.
- More common etiologies for an enlarging prevertebral collection include infection and bleeding.
- MRI without and with contrast improves sensitivity for detection of infection.
- Angiographic imaging such as CTA, MRA, and DSA allows for assessment of active bleeding or other vascular injury.
- MRI
- On spin-echo MR sequences, a hypointense flow jet should alert the radiologist to the presence of rapidly moving flow and possible CSF leak. Vascular etiologies such as active bleeding or pseudoaneurysm could appear similar but would be more thoroughly evaluated with angiographic imaging.
- Advanced imaging
- Phase-contrast MR cineradiography allows for visualization of CSF flow and can be confirmatory of a suspected dural tear and associated CSF leak.
- CT
- Traumatic CCD
- Differential Diagnoses:
- Prevertebral edema is expected in the posttraumatic and postoperative settings; however, it should slowly improve over days to weeks. Progressive prevertebral edema is abnormal and should raise suspicion for underlying pathology (eg, infection, bleeding).
- Treatment
- CCD: Surgical craniocervical fixation for stabilization
- Traumatic CSF leak: In the setting of traumatic dural injury, CSF diversion with lumbar drain may be performed to decrease flow across the tear and promote healing. When the site of tear is accessible, surgical repair/duroplasty is an alternative treatment.
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