Study Design.
A prospective randomized trial of patients enrolled at a university affiliated tertiary medical center between February and December 2017.
Objective.
To compare perioperative blood loss in patients undergoing elective posterior thoracolumbar fusion who were treated with intravenous (IV) versus oral (PO) tranexamic acid (TXA).
Summary of Background Data.
The use of antifibrinolytic agents such as TXA to decrease operative blood loss and allogenic blood transfusions is well documented in the literature. While evidence supports the use of IV and topical formulations of TXA in spine surgery, the use of PO TXA has not been studied.
Methods.
Eighty-three patients undergoing thoracolumbar fusion were randomized to receive 1.95 g of PO TXA 2 hours preoperatively or 2 g IV TXA (1 g before incision and 1 g before wound closure) intraoperatively. The sample was further stratified into three categories based on number of levels fused (1–2 level fusions, 3–5, and >5). The primary outcome was the reduction of hemoglobin. Secondary outcomes included calculated blood loss, drain output, postoperative transfusion, complications, and length of hospital stay. Equivalence analysis was performed with a two one-sided test (TOST). A P-value of <0.05 suggested equivalence between treatments.
Results.
Fourty three patients received IV TXA and 40 patients received PO TXA. Patient demographic factors were similar between groups except for body mass index (BMI). The mean reduction of hemoglobin was similar between IV and PO groups (3.36 g/dL vs. 3.43 g/dL, respectively; P = 0.01, equivalence). Similarly, the calculated blood loss was equivalent (1235 mL vs. 1312 mL, respectively; P = 0.02, equivalence). Eight patients (19%) in IV TXA group received a transfusion compared with five patients in PO TXA group (13%) (P = 0.44). One patient (2% and 3% in IV and PO, respectively) in each group experienced a deep venous thrombosis/pulmonary embolism (P = 0.96).
Conclusion.
Patients treated with IV and PO TXA experienced the same perioperative blood loss after spinal fusions. Given its lower cost, PO TXA represents an excellent alternative to IV TXA in patients undergoing elective posterior thoracolumbar fusion and may improve healthcare cost-efficiency in the studied population.
Level of Evidence: 1
Bone marrow stromal cells (MSCs) are a source of osteoblast precursors that can be recruited during bone remodeling or injury, both important processes in aging populations. With advancing age, alterations in bone structure and mineralization are often associated with an increase in osteoporosis and fracture risk. Changes in the number of osteoprogenitor cells and their osteogenic potential may occur with advancing age; however few studies have considered the influence of mechanical conditions. Here, we investigated the ability of bone MSCs from mature and aged rats to differentiate into osteoblasts and to respond to short and long periods of mechanical stimulation through signaling by ERK1/2, nitric oxide (NO), and prostaglandin E(2) (PGE(2)) during differentiation. Mineralization was delayed and reduced, but extracellular matrix production appeared less affected by increased age. Differentiating MSCs from aged animals had a decreased response to short and long periods of mechanical stimulation through ERK1/2 signaling, and to long periods of mechanical loading through NO signaling early and late during differentiation. Increases in relative PGE(2) signaling were higher in MSCs from aged animals, which could compensate for reduced ERK1/2 and NO signaling. The decreased mineralization may decrease the ability of cells from aged animals to respond to mechanical stimulation through ERK1/2 and NO signaling, with increased impairment over differentiation time. Decreasing the delay in mineralization of MSCs from aging animals might improve their ability to respond to mechanical stimulation during bone remodeling and injury, suggesting therapies for bone fragility diseases and tissue engineering treatments in elderly populations.
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