Complications of Epidural Blood Patch
According to the 2023 multisociety consensus guidelines, informed consent for epidural blood patch must include three key complications: repeat dural puncture, backache, and neurological complications 1.
The Four Major Complications to Discuss:
1. Repeat/Accidental Dural Puncture
- Occurs in approximately 0.5-1% of EBP procedures 2
- Represents a compound iatrogenic complication when performing EBP for existing post-dural puncture headache
- Must be explicitly included in informed consent (evidence grade A, high certainty) 1
2. Backache
- One of the most common complications, occurring in up to one-third of patients 3, 4
- Usually transient but can persist
- Critical pitfall: If backache persists, increases in severity, or changes in nature after EBP, other diagnoses must be investigated 1
- May indicate more serious complications developing
3. Neurological Complications
The guidelines mandate discussing neurological complications broadly 1, which encompass several serious entities documented in the literature:
- Radicular pain/radiculopathy: Can occur immediately or be delayed (up to 5 days post-procedure) 5
- Cranial nerve palsy: Associated with the underlying condition and potentially the procedure 1
- Seizures: Rare but documented with intrathecal blood injection 6
- Cauda equina syndrome: From spinal subdural hematoma 3
4. Spinal Subdural/Epidural Hematoma
- Rare but potentially catastrophic complication 3, 7
- Can present with progressive neurological symptoms
- Requires urgent neuroimaging and neurosurgical consultation
- One case series reported subdural hematoma after large-volume EBP (58 mL) 7
- Risk increases with: multiple procedures, large volumes, and prior epidural interventions causing fibrosis 3
Important Clinical Context:
The 2023 guidelines emphasize that blood should be injected slowly and incrementally, stopping if substantial backache or headache develops 1. This technique minimizes complication risk.
If neurological symptoms worsen or new focal deficits appear after EBP, urgent neuroimaging and specialist referral are mandatory (evidence grade B, moderate certainty) 1.
Additional documented complications include:
- Arachnoiditis (particularly with large-volume or repeated patches) 7
- Respiratory distress (with intrathecal injection) 6
- Facial paralysis, vertigo, tinnitus, and ataxia 4
The overall success rate of EBP is approximately 97.5%, with most complications being transient when properly managed 4.