ABSTRACT: BACKGROUND:Tranexamic acid (TXA) has been routinely delivered in multisegmental spinal decompression and bone graft fusion surgeries with satisfactory outcomes in minimizing gross blood loss and transfusion demands. However, concerns remain that intravenously delivered TXA (ivTXA) may increase risks of postoperative convulsive seizures and systemic thrombogenicity. Topical use of TXA (tTXA), being more targeted to the surgical bleeding site while minimizing patient systemic exposure to ivTXA, has been successfully applied to attenuate blood losses and transfusion requirements in hip and knee arthroplasty. Yet, randomized controlled trials on tTXA efficacy and safety are still lacking in spinal surgeries. With this knowledge gap, we hypothesize that tTXA exhibits non-inferiority to ivTXA in blood conservation and clinical safety in multisegmental spinal decompression and bone graft fusion surgeries. METHODS:A prospective, randomized, double-blind, non-inferiority study design will be adopted. The target sample size is 176. Eligible patients will be randomly allocated to receive either ivTXA or tTXA treatment. The primary end point is the perioperative total blood loss. Secondary end points consist of visible blood losses (intraoperative, postoperative 0-24?h, postoperative 0-48?h, combined perioperative blood loss, total postoperative blood loss), postoperative hidden blood loss, plasma TXA levels, postoperative conventional coagulation monitoring (prothrombin time, activated partial thromboplastin time, fiber Bragg grating, international normalized ratio), postoperative thromboelastography monitoring (reaction time, clot formation time, clot strength, fibrinolysis), postoperative hemoglobin nadir (within postoperative 48?h), perioperative transfusion amounts and rates, and length of hospital stay. Safety end points will be monitored too. DISCUSSION:This proposed study will contribute to expanding clinical evidences of tTXA for bleeding management in major spinal surgeries. This will be a high-quality prospective randomized trial with sufficient sample size, strict methodology, and few design deficits. It will investigate the potentiality of tTXA as an alternative to ivTXA in improving the current standard of care in multisegmental spinal surgeries, thereby optimizing the enhanced recovery after surgery scheme in spinal surgeries. TRIAL REGISTRATION:ClinicalTrials.gov, NCT03011866 . Registered on 5 January 2017.