Abstract 1122‐000114: Blunt Traumatic Vertebral Artery Injury: Incidence, Treatment, and Outcomes

Introduction : Blunt cerebrovascular injury (BCVI) refers to any injury to the carotid or vertebral arteries sustained via blunt trauma. Computed tomographic angiography (CTA) has become a standard and widely available screening tool for BCVI, often allowing injuries to be detected on admission. Prior research has shown that BCVI is associated with subsequent stroke. Treatment protocols vary by institution, and the optimal treatment method for these injuries is not standardized. Methods : This research was approved by the IRB. All patients presenting to a level 1 trauma center from 2011 to 2018 were screened for inclusion using the Primordial Database imaging report search tool (San Mateo, CA). All included patients underwent CTA within 24 hours of presentation. Patients were excluded if they had penetrating injury, age <16 years, or concomitant carotid injury. Data was retrospectively collected. Injuries were graded according to the criteria of Biffl et al. Treatment and follow up imaging of BCVI was determined by the vascular neurosurgeon on call. Results : A total of 2819 patients underwent screening CTA, with 156 patients (5.5%) identified with isolated vertebral artery injuries. Sixteen patients (10%) had bilateral vertebral artery injuries, for a total of 172 injured vertebral arteries. There was a male predominance (n = 97, 62%). Ninety‐two patients (59%) had a cervical spine fracture at the level of injury. Three posterior circulation strokes were detected, all within 24 hours of admission, prior to starting any treatment. Treatment regimens included aspirin (n = 135 vessels), clopidigrel (n = 1), anticoagulation (n = 2), or no treatment (n = 18). Follow up imaging was available for 84 patients (98 arteries). Three patients had worsening Biffl grade on follow‐up CTA, and the remainder were stable or improved. The three worsened injuries were all grade 2 on initial presentation. Conclusions : In our patient population, isolated blunt vertebral artery injuries were treated with multiple regimens. The majority of patients in our group were treated with aspirin; no strokes were detected after the initiation of therapy, regardless of the treatment modality or the fate of the injured. Our study is not randomized and the treatment groups are not evenly distributed. Further investigation is required to address the optimal method and duration of treatment for blunt vertebral artery injury. However, our data suggest that aspirin alone may be sufficient therapy for isolated vertebral artery injuries.

The Feasibility Study of C1 Posterior Arch Crossing Screw Fixation in Adult Thai Population: A Computed Tomographic Morphometric Analysis Study

Objective: Atlantoaxial instability can be caused by various etiologies and surgical fixation is often required. Various methods have been described for atlantoaxial fixation. Screw fixation is associated with an increased risk of vertebral artery injury especially in patients with an anomalous vertebral artery location or abnormal bony anomalies. A new C1 posterior arch crossing screw fixation technique was proposed to reduce the risk of vertebral artery injury. The present study aimed to assess morphometric CT analysis of atlas for C1 posterior arch crossing screw fixation in Thai people. Materials and Methods: The present research was an observational study that reviewed 150 computed tomography (CT) scans of the patients who had neck trauma or any other complaint requiring craniocervical investigations. Atlantoaxial articulation deformities due to trauma, infections, neoplasm, congenital anomaly, inflammatory disease, incomplete CT scan analysis, and history of surgical intervention of the cervical spine were excluded. All the images were measured for the height of the posterior tubercle, the width of the posterior arch was measured bilaterally in three parts on the axial plane, part 1: medial of the VA groove, where the arch transforms into the VA groove, part 2: the middle part between the posterior tubercle and medial of the VA, and part 3: posterior tubercle, length of the screw, and the screw projection angle was calculated. Results: Out of the 139 CT scans analyzed, the mean measurement of posterior arch height was 7.45±1.03 mm, wherein 73.3% exceed 7 mm. The mean width of the left posterior arch in part 1, 2, and 3 was 4.50±0.70 mm, 4.90±0.70 mm, and 5.70±0.80 mm, respectively, and the width of the right posterior arch in part 1, 2, and 3 was 4.50±0.70 mm, 4.80±0.70 mm, and 5.60±0.80 mm, respectively. The mean crossing screw length of the Left and Right was 17.02±3.04 mm and 17.37±2.75 mm, respectively. The mean angle of screw of the Left and Right was 24.62±3.38 degrees and 24.78±3.57 degrees, respectively. There were no significant differences in these variables between gender or sides (p>0.05) except the mean angle of the screw between gender (p<0.05). Conclusion: C1 posterior arch screw fixation is feasible in the adult Thai population. Preoperative thin-cut CT is essential for planning successful posterior arch crossing screws placement. Keywords: C1 posterior arch, Computed tomography, Crossing screw fixation