Epidural blood patches are a treatment option for patients with craniospinal hypotension or post-dural puncture headaches in which small volumes of autologous blood are injected into a patient's epidural space to stop cerebrospinal fluid leak. The procedure can be done blind or under imaging (fluoroscopy or CT) guidance and is performed predominantly by radiologists and anesthesiologists.
On this page:
Indications
craniospinal hypotension including post-dural puncture headache and spontaneous intracranial hypotension
Contraindications
allergy to any of the planned medications
injection site infection
systemic infection
anticoagulation/coagulopathy
Procedure
Epidural blood patches can be targeted (i.e. preprocedural imaging has demonstrated the site of CSF leak or at or one level below the site of dural puncture) or non-targeted 2,8.
Cannulation
At the beginning of the procedure, sterile venous cannulation (e.g. antecubital) is performed, and the cannula is connected to an extension tube (kept sterile) and flushed.
Epidural access
Interlaminar approach
Interlaminar access to the spinal epidural space can be done under fluoroscopy or CT and is essentially identical to one described in the article on lumbar interlaminar epidural injection.
Transforaminal approach
In cases where non-targeted or interlaminar blood-patches are unsuccessful, or where a ventral defect is demonstrated, then a transforaminal approach can be used (typically with CT guidance).
With CT guidance, a needle (e.g. 12-15 cm 22 G or 25 G spinal or Quincke point needle) is advanced along an anteromedial trajectory through the transverse foramen and into the ventral epidural space. Ideally, given that radiculomedullary arteries are located anterior to the nerve in the upper third of the foramen, the needle should pass through the inferior third. This may also limit the frequency of intravenous injection.
Once the epidural space is entered, extravascular and extrathecal location is confirmed with the injection of a small amount of contrast.
Depending on how well the contrast spreads craniocaudally and/or left to right repeated injections on the contralateral side or at the level above/below may be of benefit.
Injection
After an epidural location is confirmed, the patient's blood is withdrawn from the venous cannula (discarding the first 10-20 mL). This can be mixed with contrast to aid in visualizing its spread.
The blood is then slowly injected checking frequently with the patient for symptoms and performing neurological observations on the feet. The volume injected depends on the location and size of the epidural space. It can be low (e.g. 2-3 mL when performing targeted multi-needle thoracic injection) or high (e.g.10-25 mL in non-targeted lumbar epidural injection in capacious canals).
Post-procedural management
Patients should be supine for 2 hours post-EBP to promote clot formation at the site of the dural tear. Vigorous exercise, long travel and constipation which may increase the risk of dislodging the blood clot or headache recurrence should be avoided9.
Complications
Complications include 3,5:
transient back pain: most common; pain may last up to 4 weeks 6
radicular pain
intrathecal hematoma
procedure failure
Outcomes
The success rate of non-targeted epidural blood patch is variable, reported between ~75% (range 50-95%) for craniospinal hypotension and ~95% (range 90-99%) for post-dural puncture headache. In successful procedures, the patient's symptoms will objectively improve (some only temporarily), and the imaging features of craniospinal hypotension will reverse 1,4,5. Sometimes multiple blood patches are required for a successful outcome.