A Rare Case of Type II Odontoid Fracture With Bilateral Vertebral Arteries Occlusion Without Neurological Deficits

Cervical spine fractures are common fractures due to spine trauma. Odontoid fracture is responsible for 20% of cervical spine fractures. Vertebral artery injuries (VAIs) had widely focused in this setting due to its occurrence with upper cervical fractures. In our case of study, a 42-year-old female presented in the hospital’s emergency department with a history of cervical spine injury without neurological deficits. In further investigations, cervical spine X-ray, magnetic resonance imaging (MRI), and angiography were done to evaluate the possible injuries to the bone, spinal cord, and vascular structures surrounding the spine that eventuated in the accidental diagnosis of bilateral vertebral artery occlusion. This case of the study demonstrated the importance of diagnostic investigations that can evaluate in an emergency department and bilateral vertebral artery occlusion without neurological symptoms due to collateral arteries establishment.

journals.sbmu.ac.ir/Neuroscience http The serum sodium and potassium levels were 139 mEq/L and 3.8 mEq/L, respectively as well as, the erythrocyte sedimentation rate (ESR) was 45. Other laboratory studies were all in normal limits.
Radiographs of the cervical spine revealed that the axis at the base of the odontoid process had broken, defined as a type II fracture based on Anderson and D' Alonzo 3 ( Figure 1).
MRI of the cervical spine was performed to evaluate the cervical spinal cord status and ligament integrity. There was no evidence of signal anomaly or any cord compression at the atlantoaxial dislocation level ( Figure  2).
Two days before surgery for evaluating possible vascular damage during the procedure, the digital subtraction angiography brain and bilateral carotid angiography had done. Angiography revealed that bilateral vertebral arteries were completely occluded. On the left side, in V2-V3 junction, short segment dissection with 90% occlusion was seen. Cut off was evident in the V2 segment at the level of the C2 vertebra. The left posterior communicating artery's blood flow flows to the left anterior cerebral artery, which gives branches to the right vertebral basilar artery ( Figure 3). By the third hospital day, she underwent surgery to fix the fracture, which was followed by postsurgery physiotherapy. The artery occlusion dissolved by anticoagulant therapy within seven days. Thus the patient is discharged from the hospital without any neurological consequences.

Discussion:
Our patient was a 42-year-old female presented to our hospital with a history of car rollover four days before presentation, a diagnosis of type II odontoid fracture with anterior angulations made with the aid of a CT scan. In the cervical MRI study, no evidence of signal abnormality or any cord compression at the atlantoaxial dislocation level has seen. In brain and carotid angiography, complete occlusion of bilateral vertebral arteries was seen without any clinical symptoms revealed by anticoagulant therapy during hospitalization. Previously, vertebral artery damage after blunt cervical trauma was known to be rare; nevertheless, developments in imaging modalities dramatically expanded the incidence of VAI diagnoses. Patients of cervical injuries with cervical spine fractures and dislocations or transverse foramen fractures in emergency rooms should suspect of causing vertebral artery damage.
The screening of blunt cerebrovascular injury is recommended in upper C1 to C3 fractures, and the patient should undergo prompt screening. 9 One of five individuals with cervical trauma has some involvement in the axis. 10 The most seen type of axis injury is an odontoid fracture at the body's junction and dense, which is called type II fracture. C1-C2 joint can have far   more rotation from any other joint in the spine. Howbeit, tense transverse ligament limits the translational motion at the C1-C2 level. 11 Hyperflexion at the neck is the most common cause of dens fracture, leading to anterior displacement of C1-C2.
An investigation by L.R Caplan et al. demonstrated a journals.sbmu.ac.ir/Neuroscience http progressive neurological deficit in patients with bilateral artery occlusion. 12 In 1998, Okuyama et al presented the first case of bilateral vertebral arteries occlusion associated with fracture of the cervical spine. This case had wide neurological symptoms, 13 however, in our case of study, despite the occlusion of bilateral vertebral arteries, the patient did not demonstrate any clinical neurological deficit. 14 Posterior circulating disease (PCD) which includes vertebral artery occlusion is as important as an anterior circulating disease. 15 Schoen et al in 2011, demonstrated a case of basilar artery occlusion that has altered mental status and ischemia site brain MRI due to delayed diagnosis which demonstrates the importance of diagnosis of arterial occlusion in the emergency department. 16 Ausman et a. study demonstrated that PCDs existed in about 20-40% of strokes. Despite the superiority of IA angiography in detecting PCDs, MR and CT angiography are convenient screening imaging tool to evaluate PCDs. 17 Bilateral vertebral artery occlusion is common with neurological symptoms, though neurological symptoms did not exist in this case of study. In this case, the importance of clarifying acute vascular events due to spine trauma is the key to diagnosing this occlusion in an emergency department. This case of study can demonstrate the emphasis of how important can a diagnosis doubt in the emergency department can eventuate in the finding of asymptomatic disease. In this case of study, despite the vertebral artery's bilateral occlusion, neurological deficits were not present. This phenomenon is a rare condition that occurs due to the circulation of blood flow through communicating braches.
To conclude, this patient is a rare case of bilateral vertebral artery occlusion who did not demonstrate any neurological deficit, which was found accidentally. Vertebral arteries occlusion mostly accompanied by neurological deficits. This case demonstrates the importance of assessing arterial occlusion in cases with underlying disease or suspicious events, even whiteout any neurological deficit.