[Case Series] Unilateral C1-C2 vertical distraction injuries: Can we treat conservatively?

Source

·       Rawall S, et al. 2025 Apr-Jun;16(2):170-175.
doi: 10.4103/jcvjs.jcvjs_32_25.

 

Background

·         Craniocervical dissocation results from injuries that disturb the stability (through disruption of the osseoligamentous stabilizers) of the craniovertebral joint (CVJ), ranging from occipital-cervical 1 (O-C1) distraction (with or without occipital condyle avulsion) to atlantoaxial joint (AAJ) distraction (with or without odontoid fracture), to combined injuries involving both the atlanto-occipital joint (AOJ) and the AAJ.

o   In vertical distraction injuries, the transverse ligaments of the craniocervical junction (CCJ) is usually intact.

·         All CVJ injuries were thought to cause severe instability and life-threatening, until CT and MRI became more widely used, where then the milder variants of CCJ injuries were identified increasingly.

·         AAJ distraction injuries are rare and are usually treated with O-C1 or C1-C2 arthrodesis.

·         Management of incomplete or unilateral AAJ injuries are fraught with uncertainty due to lack of evidence and risk of delayed instability. This case series discusses several of those cases.

 

Case Series

·         A series of five patients, three males, two females, age ranging from 42 – 84 (average 51), sustained injuries in which four suffered from motor vehicle accidents, one from falling form standing height.

o   All five had intact consciousness (one with GCS 13, one with GCS 14, the rest are GCS 15) without neurological deficit (normal cranial nerves exam).

o   Three patients had concomitant conditions on their extremities requiring operative fixation.

·         CT and MRI were available for all five patients.

o   On CT, average LMI of the affected joint is 4.2 mm (3.6 – 4.9) vs 2.0 (1.5 – 2.5) in the unaffected, contralateral joint.

o   On CT, the average ADI was 1.6 mm (1.2 – 2.1), and average BDI was 8.68 mm (7.3 – 10).

o   On MRI, three patients show STIR hyperintensity in AAJs, four show soft tissue hyperintensity, two have definite capsular disruption / defect.

o   On MRI, all patients have intact transverse, alar, ALL, and PLL ligaments, and uninvolved spinal cord, brainstem, dural sac, and vertebral arteries.

o   One had concomitant C1 anterior arch fracture as well as left occipital condyle type 3 fracture.

o   One had subdural hemorrhage, and another had intraventricular hemorrhage.

 

·         All patients’ AAJ distractions were managed with hard cervical collar (Aspen) for 6 weeks, and radiologically followed up for on average of 876 days (42 – 2920 days).

o   Average hospital stay was 6.3 days (2-13).

o   Four were discharged to home, one to skilled nursing facility.

o   Flexion extension cervical radiographs were obtained at 6 weeks post-injury for all patients, with no evidence of instability.

o   All patients were appointed at an outpatient setting at least once.

o   During those, there were no delayed instability, return to operating room, or neurological deficit.

Discussion

·         AAJ and AOJ are the main joints of the CCJ along with their supporting ligaments.

o   AAJ accounts for a significant portion of movement of the cervical spine and the majority of cervical axial rotation.

o   CCJ injury must be suspected in all high energy trauma, and be identified when present, as it is commonly harboring injuries to the spinal cord, cranial nerve, vertebral arteries, and long term disability and pain with rapid (often preventable) neurological deterioration when missed early.

·         CCJ stabilizers are mainly its intrinsic ligaments:

o   AAJ, and AOJ capsules (AOJ capsule being the most significant stabilizer of CCJ).

o   Tectorial membrane.

o   Transverse ligament.

o   Alar ligaments.

o   Apical ligament.

·         CCJ injuries used to be considered lethal across the board, diagnosed in all-or-none fashion, and its sufferers rarely managed to survive trip to hospital before a generalized treatment of O-C2 arthrodesis was undertaken.

·         With the wider use of CT and MRI, and improved prehospital care, milder CC injuries had been increasingly identified, expanding the spectrum of CC injuries beyond severe complete AOJ distraction and bilateral / complete AAJ distraction, into unilateral / incomplete AAJ distraction which requires distinct management than their more severe counterparts.

·         It has been noted that AOJ distractions are virtually always accompanied by AAJ distraction, but not vice versa.

o   AOJ distraction usually has neurological deficit vs AAJ distraction, which usually has no neurological deficit and no vertebral artery injury.

·         Halo vest has conflicting results and reports suggesting worsening CCJ.

·         Suspected CCJ injuries should have the patient’s body fixated with sandbags along its length and in reverse Trendelenburg to resist distracting forces.

·         Save some reports of rare cases, CCJ injuries other than incomplete AAJ distractions are successfully treated operatively with O-C2 or AA arthrodesis (depends on the integrity of AOJ capsule).

o   There had been reports of cases of complete AAJ distraction, AOJ + AAJ distraction (was managed with hard cervical collar), and CVJ dislocation nonoperatively.

·         O-C2 or AA arthrodesis are morbid procedures as it fixates their mobility, yet incomplete / unilateral AAJs are benign conditions that are usually manageable conservatively with hard cervical collar.

o   In this case series, the five patients of incomplete AAJ distraction has varying degrees of integrity of CCJ ligaments, without AOJ distraction, all managed conservatively without delayed instability or neurological deficit during the follow up.

·         Further diagnostic criteria for these variants of CCJ injuries and their ideal management should be explored.