Additional harms associated with neuraxial blocks

In addition to the harms associated with regional blocks, neuraxial blocks are also associated with hypotension, and haematoma or abscess.

Hypotension is due to spinal or epidural sympathetic nerve block, which is more marked if the patient is hypovolaemic.

A haematoma or abscess can cause nerve compression and potentially permanent neurological damage. This is a medical emergency and requires urgent investigation with magnetic resonance imaging (MRI) and referral to a neurosurgeon to preserve neurological function. New onset of neck or back pain, with or without a neurological abnormality, can indicate an epidural or spinal abscess or haematoma. Development of a haematoma or abscess should be considered even after the patient is discharged from hospital. Early diagnosis and treatment increase the likelihood of partial or full neurological recovery.

Risk factors for abscess formation include prolonged use (more than 4 days), elderly patients (due to degenerative spine abnormalities and peripheral vascular disease), multiple needle insertion attempts and immune compromise.

Risk factors for haematoma formation include coagulopathies or concurrent anticoagulant, antiplatelet or thrombolytic use—avoid neuraxial blocks in these patients.