Nerve damage

Damage to one or more nerve roots can cause sensory or motor symptoms. Although these are usually transient, they can be permanent. The risk is very low, so accurate estimates are difficult to make. However, a recent study (Auroy 2002) gives a risk of <8 per 10000 spinals (peripheral neuropathy or cauda equina syndrome).

Paralysis

Permanent paralysis of the lower limbs is extremely rare. It can occur as a result of spinal abscess or spinal haematoma. Because the incidence of both is so small, a true incidence of paralysis is hard to measure. However, based on the limited literature, a reasonable ‘best guess’ risk is <1 per 100 000 spinals (Horlocker & Wedel 2000) and this is borne out by the more recent Royal College of Anaesthetists’ 3rd National Audit Project.

Epidural abscess

The risk of this rare complication is very low and is kept low by assiduous attention to asepsis: hat, mask, gown, gloves and appropriate skin preparation.

Epidural haematoma

This rare complication is most likely in patients with disordered coagulation, either iatrogenic or pathological.

Meningitis

Risk of this complication can be reduced if assiduous attention is paid to asepsis: hat, mask, gown, gloves and appropriate skin preparation.

Total spinal

This refers to a block which rises high enough to cause complete paralysis, usually (but not always) accompanied by unconsciousness, hypotension and bradycardia, as sympathetic block also rises.

It is uncommon after a single shot spinal, because of the small volume of injected drug. However, if spinal follows a top-up of an existing epidural, e.g. in obstetrics, the breach in the dura can allow a large volume of local anaesthetic solution to pass from the epidural space to the subarachnoid.

Treatment is supportive: ventilation with airway protection, intravenous fluids, antimuscarinics and vasopressors.