Patient information

Your anaesthetic choices

For surgery on an arm or leg, your anaesthetic may be a nerve block, a general anaesthetic, or both. Your anaesthetist will discuss which options are suitable for you.

This page is mainly about nerve blocks. It also lists the risks of a general anaesthetic, so you can compare the two.

Nerve block alone

Arm or leg numbed

You can stay awake, with or without sedation (medicine to help you relax). For some operations, the block can be the only anaesthetic.

Nerve block + general anaesthetic

Asleep + pain relief

You are asleep during surgery, and the block gives you pain relief afterwards.

General anaesthetic

Asleep for surgery

You are asleep during the operation.

What is a nerve block?

Local anaesthetic is injected beside the nerves that supply your arm or leg. This numbs the nerves, so for a while you lose feeling and power in that limb.

Nerve blocks are often used for operations on an arm or leg, including bone and joint surgery (orthopaedics), plastic surgery and blood vessel surgery (vascular surgery).

What happens when you have a nerve block?

The usual steps are:

  1. MonitoringA drip (a thin tube into a vein) is put in, and monitors check your heart rate, blood pressure and oxygen level.
  2. UltrasoundAn ultrasound scan shows the nerves, as well as nearby blood vessels and other tissue.
  3. InjectionLocal anaesthetic is injected beside the nerve. You may feel some pressure or tingling.
  4. Numb limbYour arm or leg becomes numb and heavy.
  5. SurgeryOnce the area is numb, surgery can begin.

What will I experience?

Nerve block alone

With light sedation or none

  • You are usually awake
  • A screen hides the operation from view
  • You may hear talking or equipment
  • Sedation may be given
  • Your limb stays numb afterwards

Nerve block + general anaesthetic

Asleep for the operation

  • You are asleep during surgery
  • The block can be done before or after you go to sleep
  • Your limb is numb when you wake
  • The block continues to give pain relief afterwards

Benefits of a nerve block

Excellent pain reliefOften for several hours after surgery.
Less strong pain medicineMay reduce the need for high doses of strong painkillers.
Fewer side effects from medicineMay reduce the sickness, itching and constipation that strong painkillers can cause.
May avoid a general anaestheticFor some operations, a nerve block can be the only anaesthetic.
Earlier recoveryMay help you get back to the ward, eat, drink and go home sooner.

How do the risks of a nerve block compare with a general anaesthetic?

These figures are from the current ISRA patient leaflet.

What the numbers mean: "1 in 100" means about 1 person in every 100 is affected. The other 99 are not.

If you have a nerve block and a general anaesthetic, the risks of both apply.

1 in 3Very common

Nerve block

None listed

General anaesthetic

  • Sore throat

1 in 100Common

Nerve block

  • Discomfort
  • Pressure
  • Tingling
  • The block not working fully (block failure)
  • Bruising
  • The needle entering a blood vessel

General anaesthetic

  • Damage to teeth
  • Feeling or being sick
  • Shivering
  • Confusion or memory problems
  • Difficulty passing urine
  • Dizziness

1 in 1,000Uncommon

Nerve block

  • Temporary nerve injury
  • Infection

General anaesthetic

  • Injury to a nerve (peripheral nerve injury)

1 in 10,000Rare

Nerve block

  • Permanent nerve injury

General anaesthetic

  • Severe allergic reaction (anaphylaxis)

1 in 100,000Very rare

Nerve block

  • Allergy to local anaesthetic
  • A toxic reaction to local anaesthetic in the bloodstream (local anaesthetic toxicity)

Blocks near the neck also carry a very rare risk of a punctured lung, or of the local anaesthetic being injected into the area around the spinal cord by mistake (spinal, subdural or epidural injection).

General anaesthetic

Less than 1 in 100,000

  • Loss of sight
  • An inherited reaction causing breathing difficulties
  • Being aware during surgery
  • Death

Important after your operation

While your arm or leg is numb

Your arm or leg may stay numb, weak or heavy for up to 24 hours.

Protect itYou may not feel it if your limb is knocked, pressed or too hot. Use the support or raised position your team advises.
Move safelyDo not stand on a numb leg until staff have shown you how to move around safely.
Start pain relief earlyTake your prescribed pain medicine before the block fully wears off.

Want more detail?

The full patient leaflet has more information about the procedure, recovery and risks.

This information supports discussion with your anaesthetist and does not replace advice about your individual care.