In Reply: Traumatic Vertebral Artery Injury After Subaxial Cervical Spine Injuries: Incidence, Risk Factors, and Long-Term Outcomes: A Population-Based Cohort Study

To the Editor: We read with interest the letter by Zhang and Wang1 regarding our manuscript entitled: “Traumatic vertebral artery injury after subaxial cervical spine injuries: incidence, risk factors, and long-term outcomes: a population-based cohort study.”2 We thank them for their appreciation of our work and welcome their valuable insights on the topic. Zhang and Wang bring up valid concerns surrounding the potential limitations with the Denver scale, which may not completely account for the full complexity of the vertebral artery injury (VAI). The Denver or Biffl grading scale for blunt cerebrovascular injury is, however, the most commonly used score in this context and has been fairly validated over the years since its inception in the late 90s,3 with guidelines currently recommending its use.4-6 Nonetheless, we do believe that, as pointed out by the authors, computed tomography perfusion studies could add some perspective regarding the extent of the associated perfusion insult to the brain. However, these studies are not routinely performed at our hospital and were, hence, lacking. The authors also make a good point highlighting the fact that patients who did not receive anticoagulation or antiplatelet therapy in our cohort were likely those who exhibited contraindications to those treatments. It is indeed the case. Patients with complications such as concomitant traumatic brain injury or hemorrhages resulting from the trauma were not administered anticoagulation or antiplatelet therapy. As mentioned in our discussion section, “this reflects treatment choices in situation(s) […], where blood thinners and hence bleeding complications ought to be avoided.” Despite that, none of the patients developed neurological complications related to their arterial injury, acknowledging that stroke-related neurological deficits may be hard to clinically assess due to concomitant spinal cord injury in most patients. In addition, our study only focuses on patients with subaxial cervical injuries who received surgical treatment which introduces a selection bias, as mentioned in both the letter by Zhang and Wang as well as our limitation section. We would, however, like to emphasize that a project where we look at all patients admitted to our level 1 trauma center with injuries to the cervical spine, regardless of treatment, is currently underway. Through that, we expect to be able to examine risk factors for blunt cerebrovascular injury in patients with trauma involving the cervical spine, in a more thorough manner and while minimizing the potential risk of selection bias. Nonetheless, our results will only be applicable to this specific population of patients and will not be generalizable to the entirety of patients with cervical injuries, including minor ones, pending future validation. Finally, we agree with Zhang and Wang on the fact that health-related quality-of-life outcomes would really aid in comprehending the full extent of VAI outcomes. However, these data were not collected at the time and would be impractical to gather now due to the retrospective nature of our study. Future research studying the short-term and long-term impacts of VAI on health-related quality-of-life outcomes is needed and encouraged further our understanding of VAI-associated health outcomes.