Increased vertebral exposure in anterior lumbar interbody fusion associated with venous injury and deep venous thrombosis

Background Published outcomes on anterior lumbar interbody fusion (ALIF) have focused on 1-2 level fusion with and without vascular surgery assistance. We examined the influence of multi-level fusion on exposure-related outcomes when performed by vascular surgeons. Methods We retrospectively reviewed clinical and radiographic data for patients undergoing anterior lumbar interbody fusion (ALIF) with exposure performed by vascular surgeons at a single practice. Results From 2017-2018, 201 consecutive patients underwent vascular-assisted ALIF. Patients were divided by number of vertebral levels exposed (90 patients with 1 level exposed, 71 with 2, 40 with 3+). Demographically, 3+ level fusion patients were older (p=.0045) and more likely to have had prior ALIF (p=.0383). Increased vertebral exposure was associated with higher rates of venous injury (p=.0251), increased procedural time (p= .0116), length of stay (p=.0001), and incidence of postoperative DVT (p=.0032). There was a 6.5% rate of intraoperative vascular injury, comprised of 3 major and 10 minor venous injuries. In patients who experienced complications, 92.3% of injuries were repaired primarily. 23% of patients with venous injuries developed postoperative deep venous thrombosis. In a multivariate logistic regression model, increased levels of exposure (RR = 6.23, p = .026) and a history of degenerative spinal disease (RR = .033, p = .033) were predictive of intraoperative venous injury. Conclusion Increased vertebral exposure in anterior lumbar interbody fusion is associated with increased risk of intraoperative venous injury and postoperative deep venous thrombosis, with subsequently greater lengths of procedure time and length of stay. Rates of arterial and sympathetic injury were not affected by exposure extent.