BACKGROUND: Traditional techniques for obtaining hemostasis during orthopedic surgery, such as conventional electrocautery and sealants, have limited clinical effectiveness in reducing hemoglobin (Hb) loss and requirement for transfusion. The bipolar tissue sealant device studied in this trial combines radiofrequency energy with saline irrigation to hemostatically seal both cut bone and soft tissue, potentially aiding hemostasis. STUDY DESIGN AND METHODS: Sixty patients undergoing multilevel posterior lumbar instrumentation and fusion were randomly assigned to unipolar cautery alone (control group) or unipolar cautery plus use of the bipolar tissue sealant device (treatment group). Hb loss from the surgical field was measured (rather than estimated) and compared between the two groups. The primary hypothesis was that the treatment group would lose significantly less Hb than the control group. RESULTS: The control group experienced a mean Hb loss of 102.4 g while the treatment group showed a significantly lower mean Hb loss of 66.2 g (p = 0.0004). No significant difference was found between groups with respect to secondary endpoints including length of surgery, number of red blood cell units transfused, number of total blood component units transfused, transfusion avoidance, length of stay, or serious adverse events. CONCLUSION: Use of a bipolar tissue sealant device in addition to unipolar cautery significantly decreased Hb loss during multilevel, posterior lumbar spinal instrumentation and fusion when compared with unipolar cautery alone.