What is the risk of epidural hematoma following neuraxial blockade in patients who have recently received enoxaparin for thromboprophylaxis?
There is an increased risk of causing spinal/epidural hematoma from an epidural or intrathecal puncture in patients who are receiving low molecular weight heparin. This is supported by a number of case reports, however the total number of patients who have undergone neuraxial blockade without complications while receiving low molecular weight heparin is unknown. A review by Bergqvist et al reports only one case of spinal hematoma in 1000000 patients who received the combination of epidural or spinal anesthesia and low-dose low molecular weight heparin for thromboprophylaxis, and that no spinal hematomas were reported in at least 10000 patients who received the combination of low molecular weight heparin and epidural or spinal anesthesia3, 4, 5. However, the specific type of low molecular weight heparin and dosing regimen differs between the United States and Europe, and the results in this patient population may not apply to enoxaparin as it is currently dosed in the United States for thromboprophylaxis (30 mg SQ every 12 hours).
Factors associated with spinal/epidural hematomas include presence of therapeutic anticoagulation (i.e., full heparinization), preexisting coagulopathy, intraoperative use of low molecular weight heparin or administration shortly after completion of the surgical procedure, technically difficult needle or catheter insertion, traumatic ("bloody ") taps, and presence of preexisting spinal canal pathology such as ankylosing spondylitis or spinal vascular malformations6, 7, 8.
Case reports demonstrate that spinal/epidural hematomas can also occur spontaneously in patients receiving low dose low molecular weight heparin9 or antiplatelet therapy , and in patients who have vascular abnormalities or neoplastic disease of the spinal canal. This makes it nearly impossible to demonstrate a causal relationship between spinal hematoma and epidural or spinal anesthesia.
REFERENCES
3. Bergqvist-D, Lindblad-B, Matzsch-T. Low molecular weight heparin for thromboprophylaxis and epidural/spinal aaesthesia - is there a risk? [review] Acta Anaesthesiol Scand. 1992;36:605-9.
4. Modig-J. Spinal or epidural anaesthesia with low molecular weight heparin for thromboprophylaxis required careful postoperative neurological observation [editorial]. Acta Anaesthesiol Scand 1992:36;603-4.
5. Pham-J, Montefiore-A, Deschamps-A. Low molecular weight heparin and epidural/spinal anaesthesia - is there a risk? [comment] Acta Anaesthesiol Scand 1994:38;303-4.
6. Wulf-H. Epidural anaesthesia and spinal hematoma [review] Can J Anaesth. 1996;43(12):1260-71
7. Hynson-J-M, Katz-J-A, Ulrich Bueff-H. Epidural hematoma associated with enoxaparin [case report]. Anesth Analg 1996; 82:1072-5.
8. Sternlo-J-E, Hybbinette-C-H. Spinal subdural bleeding after attempted epidural and subsequent spinal anaesthesia in a patient on thromboprophylaxis with low molecular weight heparin. [case report] Acta Anaesthesiol Scand. 1995;39:P 557-9.
9. Metzger-G and Singbartl-G. Spinal epidural hematoma following epidural anesthesia versus spontaneous spinal subdural hematoma. Two case reports. Acta Anaesthesiol Scand. 1991;35:105-7.