Viscoelastic Hemostatic Assays in Spine Surgery: A Scoping Review of Perioperative Transfusion Practices and Coagulation Assessment.

Abstract

Major spine surgery is associated with substantial blood loss and dynamic perioperative coagulation disturbances. Conventional coagulation tests may not adequately assess whole-blood clot formation, platelet contribution, or fibrinolysis. Viscoelastic hemostatic assays (VHAs), including thromboelastography and rotational thromboelastometry, have been explored for point-of-care coagulation assessment in spine surgery. This scoping review systematically mapped the literature evaluating VHA-guided transfusion practices and perioperative coagulation assessment in spine surgery, focusing on devices used, timing of testing, and reported clinical outcomes. The primary objective was evidence mapping rather than quantitative effect estimation or meta-analysis. The review followed a Population-Concept-Context framework and was reported in accordance with PRISMA-ScR guidelines. Electronic databases and gray literature were searched from inception to August 29, 2025. Eligible studies included patients undergoing spine surgery in whom VHAs were used perioperatively, evaluating system-level outcomes (devices, timing, algorithms, cost-effectiveness) and clinical outcomes (blood loss, transfusion composition and volume, pharmacotherapy, hypercoagulability, and hospital length of stay). Twenty-one studies met inclusion criteria, comprising 3 randomized controlled trials, 9 prospective observational studies, 8 retrospective cohort studies, and 1 case-control study. Most studies were observational with marked heterogeneity in design, patient populations, and surgical settings. Several studies reported targeted blood product administration with VHA-guided management. Evidence regarding reductions in blood loss and hospital stay was inconsistent, while data on hypercoagulability, thromboembolic events, and cost-effectiveness were limited. Though studies suggest that VHA may guide patient blood management in spine surgery, the evidence is predominantly observational, limiting causal inference and underscoring the need for well-designed, spine-specific studies.