Validated intraoperative bleeding severity scale (VIBe) for hemostasis assessment in lumbar spinal fusion: a prospective, randomized controlled trial

Abstract

Purpose Intraoperative bleeding remains a major challenge in lumbar spine surgery, with conventional assessment methods lacking standardization. The Validated Intraoperative Bleeding Severity Scale (VIBe) is a structured five-grade tool developed to objectively assess bleeding severity across surgical fields. This study evaluated the clinical utility of VIBe in lumbar spinal fusion by comparing it with conventional bleeding metrics across various hemostatic strategies, including hypotensive anesthesia and local hemostatic agent use. Methods In this prospective, randomized controlled trial, 70 patients undergoing elective posterior lumbar decompression and fusion were randomized to normotensive or hypotensive anesthesia. Each group was further divided by hemostatic strategy: active agents alone or a combination of active and passive agents. VIBe grades were independently recorded by the surgeon and assistant for each bleeding site. Conventional bleeding metrics-including estimated blood loss (EBL), transfusion volume, and drain output-were also collected. Between group comparisons and inter-rater agreement were assessed, and correlation analysis was performed to evaluate the association between the VIBe and conventional bleeding metrics. Results VIBe grades improved significantly after hemostasis in all patients (p < 0.001). Although intraoperative blood pressures were significantly lower in the hypotensive group, there were no significant differences in transfusion volume, EBL, drain output, or VIBe-based assessments. Outcomes were also comparable between patients receiving combined versus active-only hemostatic agents. Inter-rater agreement for VIBe scores before hemostasis, after hemostasis, and for score changes was near-perfect (kappa = 0.934, 0.834, and 0.856 respectively, all p < 0.001). Operator-assigned VIBe scores significantly correlated with EBL (rho = 0.305, p = 0.010) and transfusion volume (rho = 0.264, p = 0.027); assistant correlated with EBL (rho = 0.284, p = 0.017). Conclusion VIBe is a reliable and reproducible tool for intraoperative bleeding assessment in lumbar spine fusion. Active hemostatic agents were effective, and the addition of passive agents offered no measurable advantage.