Regional anesthesia and analgesia in the orthopedic patient receiving thromboprophylaxis

Spinal and epidural anesthesia/analgesia provide several advantages over systemic opioids, including superior analgesia, reduced blood loss and need for transfusion, and decreased incidence of thromboembolic complications. The current medical practice is that patients hospitalized for major surgery often receive an anticoagulant and/or antiplatelet medication perioperative to prevent venous thrombosis and pulmonary embolism, although the pharmacologic agent, degree of anticoagulation desired, and duration of therapy remain controversial. In the United States, oral anticoagulants and low-molecular-weight heparin are most often used in patients undergoing major orthopedic surgery, whereas low-dose (unfractionated) heparin or aspirin may be used in patients undergoing thoracoabdominal surgery or in elderly or debilitated patients, who have an increased risk of hemorrhage. Patients receiving perioperative thromboprophylaxis are often not considered candidates for spinal or epidural anesthesia/analgesia because of a theoretically greater risk of spinal hematoma. The decision to perform neuraxaal blockade on these patients must be made on an individual basis, weighing the potentially greater risk of spinal hematoma from needle or catheter placement against the theoretical benefits gained. To reduce the risk of spinal hematoma associated with regional anesthesia, it is necessary to understand the mechanisms of coagulation, the pharmacologic properties of the anticoagulant and antiplatelet agents, and also the clinical studies involving patients undergoing neuraxial blockade while receiving these medications.