Intraspinal hematoma is a relatively rare condition resulting from a variety of causes. Traumatic causes include lumbar puncture and neuraxial anesthesia. It is more likely to occur in anticoagulated or thrombocytopenic patients, patients with neoplastic disease, or in those with liver disease or alcoholism. Approximately one-quarter to one-third of all cases are associated with anticoagulation therapy. The risk of intraspinal hematoma formation after administration of neuraxial anesthesia and analgesia is increased in patients who have received anticoagulant therapy or have a coagulation disorder.1 For this reason, neuraxial anesthesia is often contraindicated in the presence of a coagulopathy. Other risk factors for the development of epidural or spinal hematoma include technical difficulty (multiple attempts) in the performance of the neuraxial procedures due to anatomic abnormalities of the spine and multiple or bloody punctures.
The incidence of spinal hematoma was originally reported to be one in 150,000 epidurals and one in 220,000 spinal anesthetics.2 Recent epidemiologic studies have shown the incidence of spinal hematoma to be more frequent, ranging from one in 2700 to one in 19,505 epidurals.3,4,5,6 The most recent study showed an overall risk of 1 in 21,643 epidural injections.7 The elderly (one in 3800)4 are at increased risk due to degenerative spine abnormalities, osteoporosis, and peripheral vascular disease.8,9 Obstetric populations seems to have a lower incidence of spinal hematoma (one in 200,000),4 probably secondary to the hypercoagulable state of pregnancy, the wider capacity of the epidural space in younger parturients, and higher intra-epidural pressure. Based on a recent large retrospective study, the incidence of epidural hematoma in patients with abnormal coagulation may be as low as one in 315 patients.10
The introduction of low-molecular-weight heparin (LMWH) was associated with a spike in the incidence of spinal hematoma, resulting in a warning by the Food and Drug Administration (FDA) and the introduction of the first consensus statement on regional anesthesia in patients on anticoagulants by the American Society of Regional Anesthesia and Pain Medicine (ASRA) in 1998.11 The guidelines were based on an extensive review of the literature and of the pharmacology of the different anticoagulants. Recommendations were made on the timing of the neuraxial block, removal of the epidural catheter, and the subsequent administration of anticoagulants. In particular, the use of low concentrations of local anesthetics for epidural infusion (to preserve motor strength for easier monitoring) and subsequent neurologic monitoring were recommended by the ASRA. The consensus guidelines, published in 1998 and updated in 2003 and 2010,12,13 have greatly assisted clinicians in decision making with regard to the use of neuraxial procedures in the setting of anticoagulation therapy. Two other sets of guidelines, published by the European Society of Anaesthesiology and the Scandinavian Society of Anaesthesiology and Intensive Care Medicine, are influential in Europe.14,15