Regional/Spinal Anaesthesia

Regional or spinal anaesthesia is a technique where an anaesthesiologist (a doctor who specialises in pain control and sedation) injects local anaesthetic (numbing medicine) near specific nerves or into the fluid-filled space around the spinal cord, blocking pain signals from a defined part of the body while the patient stays awake or lightly sedated.

Unlike general anaesthesia, which puts the whole body to sleep, regional anaesthesia works by interrupting nerve signals only in the targeted area — usually the lower half of the body. The medicine travels to the nerves responsible for feeling and movement in that region. Within minutes, those nerves stop sending pain messages to the brain. The effect lasts for the duration of the procedure and then gradually wears off as the body clears the medicine.

Spinal and regional anaesthesia is chosen when a surgeon needs to operate on the lower body, pelvis, or one limb without putting the patient fully to sleep, or when general anaesthesia carries a higher risk for that particular patient. It is also used to manage pain after major surgery.

• Caesarean section (C-section) — childbirth by surgical opening of the abdomen and uterus
• Hip or knee replacement surgery
• Hernia repair in the groin or lower abdomen
• Prostate surgery or procedures on the bladder
• Surgery on the legs or feet
• Repair of fractured bones in the lower limb
• Haemorrhoid (piles) surgery or procedures around the anal region
• Pain relief during labour (epidural analgesia)
• Post-operative pain control after abdominal or chest surgery (epidural catheter left in place)

Regional anaesthesia is not always the right choice. The care team will discuss alternatives if any of the following apply.

• The patient is on strong blood thinners and cannot safely stop them in time
• There is an infection on the skin at the injection site
• The patient has a blood-clotting disorder that has not been corrected
• Raised pressure inside the skull (intracranial hypertension) — for certain types of regional block
• The patient firmly refuses and does not consent to being awake during surgery
• The planned operation is on a part of the body that cannot be reached by regional block

Spinal and regional anaesthesia is generally considered safer than general anaesthesia for many patients, but like all medical procedures it carries recognised risks that the anaesthesiologist will discuss with you beforehand.

• Headache after spinal anaesthesia (post-dural puncture headache) — a throbbing headache that is usually worse when sitting or standing; most cases settle within a few days
• Low blood pressure (hypotension) — the nerve block can widen blood vessels and cause a temporary drop in blood pressure; the team monitors this closely and treats it quickly
• Incomplete block — the anaesthetic may not fully numb the intended area, sometimes requiring additional medicine or a switch to general anaesthesia
• Backache at the injection site — usually mild and temporary
• Bruising or bleeding at the injection site
• Difficulty passing urine (urinary retention) — especially after spinal or epidural anaesthesia; a urinary catheter is often placed to help
• Nausea and shivering — relatively common during and just after the procedure
• Nerve irritation or, rarely, nerve injury — temporary tingling, numbness, or weakness in the legs; permanent nerve damage is uncommon
• Epidural haematoma (a blood clot pressing on the spinal cord) — rare but serious; more likely if blood thinners were not stopped appropriately
• Infection — meningitis (infection of the membranes around the brain and spinal cord) or epidural abscess (a pus pocket near the spine) are very rare but serious complications
• Total spinal block — if the medicine spreads higher than intended, it can temporarily affect breathing; the anaesthesiology team is trained to manage this immediately

Preparation for regional or spinal anaesthesia involves steps before you arrive, tests the team will run, and specific actions taken on the day. Your anaesthesiologist will give you personalised instructions, and it is important to follow them carefully.

Before the procedure, the team usually asks patients to fast (have nothing to eat or drink) for a number of hours. This is required even though you will not be fully asleep, because situations can change during surgery and it may become necessary to give general anaesthesia. The exact fasting period depends on what food or drink was last consumed — the care team will specify this. Blood thinners, anti-inflammatory painkillers, and certain diabetes medicines are commonly paused before the procedure; your anaesthesiologist will advise which medicines to continue or stop and for how long. Smoking and alcohol are best avoided in the days before, as both can affect blood pressure control and healing.

Before the day of surgery, the team may run some or all of the following tests to make sure the anaesthesia is safe for you.

• Blood tests — to check clotting ability, blood count, kidney function, and electrolyte (salt) levels
• Blood pressure measurement
• EKG (electrocardiogram — a tracing of the heart's electrical activity), especially in older patients or those with heart conditions
• Imaging of the spine in some cases, for example if the patient has had previous back surgery or has a known spinal deformity

On the day of the procedure, here is what typically happens, step by step. The exact sequence and number of steps may vary between hospitals and anaesthesiologists.

• 1. You change into a hospital gown and confirm your identity, procedure, and allergy history with the nursing team.
• 2. A small intravenous (IV) cannula (a thin plastic tube inserted into a vein, usually in the hand or arm) is placed so that fluids and medicines can be given quickly if needed.
• 3. Monitoring equipment is attached: blood pressure cuff, pulse oximeter (a clip that measures oxygen in the blood), and heart monitor leads.
• 4. You are positioned carefully — usually sitting bent forward or lying on your side, curling the lower back to open the spaces between the vertebrae (the bones of the spine).
• 5. The skin over the injection site is cleaned thoroughly with antiseptic solution.
• 6. A small amount of local anaesthetic is injected just under the skin to numb the surface — most patients describe a brief sting.
• 7. The anaesthesiologist then advances the spinal needle into the correct space. For a spinal block, local anaesthetic is injected into the cerebrospinal fluid (the clear fluid surrounding the spinal cord). For an epidural, a thin soft catheter (tube) is threaded into the epidural space just outside that fluid, allowing medicine to be given continuously or in doses.
• 8. The needle is removed and a small dressing is applied to the site.
• 9. You are helped onto your back and the team tests whether numbness has spread to the correct area, often by touching the skin with a cold or sharp object.
• 10. Once adequate block is confirmed, the surgical team begins. The anaesthesiologist stays present throughout, monitoring vital signs and adjusting sedation or additional pain relief as needed.

After regional or spinal anaesthesia, the numbness does not disappear immediately — it gradually wears off over one to several hours depending on which medicine was used and how much. During this time, it is important that the affected limbs are protected from pressure and heat, because you cannot feel them properly. The nursing team will monitor your blood pressure, heart rate, oxygen levels, and the return of sensation and movement before you are considered ready to move to the ward or go home.

• Stay in the recovery area or ward until sensation, movement, and the ability to stand safely have returned — the nurse will assess this at regular intervals.
• Keep the numb area away from hot surfaces, tight clothing, or sharp objects until full feeling returns.
• If a urinary catheter was placed, it is usually removed once you can walk and control your bladder again.
• If an epidural catheter was left in for ongoing pain control, the nursing team will care for the catheter site and adjust the medicine drip according to the doctor's instructions — report any new back pain, fever, or weakness immediately.
• Headache after spinal anaesthesia is common; lying flat, drinking fluids, and simple pain relief usually help. If the headache is severe or does not improve within a day or two, tell the team — a procedure called a blood patch (injecting a small amount of your own blood into the epidural space to seal the leak) can give fast relief.
• Avoid driving or operating heavy machinery until full sensation and motor control have returned and any sedation medicine has fully cleared — your doctor will advise when this is safe.
• Strenuous activity, heavy lifting, and alcohol should be avoided for at least the period your surgical and anaesthesia team recommends.
• Attend all follow-up appointments. If you notice persistent numbness, weakness, severe back pain, fever, loss of bladder or bowel control, or any other unexpected symptom after going home, seek medical attention promptly.