A study published in The Spine Journal indicates that the incidence of vertebral artery injury is higher among less experienced spinal surgeons compared with more experienced surgeons. However, on average, a spinal surgeon encounters their first vertebral artery injury when they have been working for an average of 10.2 years—indicating that the complication is not just a result of inexperience.
Study authors David Lunardini (Department of Orthopaedic Surgery, University Pittsburgh Medical Center, Pittsburgh, USA) and others write that vertebral artery injury is a “rare but serious” complication of spinal surgery. They add that previous studies of the incidence of the complication are “primarily from a single surgeon or smaller multicentre case series with as few as 41 patients.” Therefore, the aim of their study was to gather a large sample of high-volume surgeons to “attempt to clarify the incidence and risk factors for vertebral artery injury”.
Lundarini et al sent an anonymous 10-question survey to all members of the Cervical Spine Research Society (CSRS) to determine how many cervical spine cases they performed each year and how many vertebral artery injuries they encountered as the primary surgeon. Of the 195 members contacted, 141 responded (72%) and 68 of them admitted encountering at least one vertebral artery injury during their career. Overall, 111 vertebral artery injuries were reported—resulting in an incidence rate of 0.07% for the whole survey population.
The average rate of vertebral artery injury was 0.528% (range 0–3.8%) for surgeons who had performed 300 or fewer cases in their career compared with 0.074% (range 0–6%) for surgeons who had performed more than 300 cases in their career (p=0.028). The authors state that the 23 surgeons in the survey who performed 300 cases or fewer accounted for 15 of the vertebral artery injuries reported with an overall incidence rate of 0.33%. They add: “Using chi-squared analysis, this equates to an odds ratio of vertebral artery injury by a less experienced surgeon of 5.6.” But, Lunardini et al comment: “The average vertebral artery occurrence was at career year 10.2 that however argues against vertebral artery injury being purely an error of surgical inexperience.”
Other findings in the study showed that one fifth of vertebral artery injuries involved an anomalous course of the vertebral artery, one fifth of injuries occurred during the surgical approach, and the posterior exposure accounted for 11.1% (vs. 7.2% for the anterior exposure) of injuries. Furthermore the authors found that while most of the injuries reported did not result in serious injury, 10% of cases resulted in neurologic injury or death.
Based on their findings, Lunardini et al conclude: “Particular attention to avoiding vertebral artery injury should be spent during the highest risk portions of the case that included posterior instrumentation of the upper cervical spine, anterior corpectomy, and posterior exposure of the cervical spine.”