Spinal Anaesthesia is where the anaesthetic is injected into the fluid just outside the spinal cord in your back rendering the lower half of the body numb to pain and feeling. The anaesthetic typically wears off in 2 – 4 hours, however pain relief may last for periods of up to 24 hours.
Indications for this technique include surgical procedures to the lower body and in combination with general anaesthesia to provide analgesia for upper abdominal surgery. Depending on the type of operation and your own medical condition, a spinal anaesthesia may sometimes be safer for you and suit you better than a general anaesthetic.
- Prior to the administration of the anaesthetic, a needle will be used to insert a cannula into a vein in your hand or arm and intravenous fluids will be commenced.
- You will either sit on the side of the bed with your feet on a low stool or lie on your side with your knees tucked up towards your chest.
- Your anaesthetist will have the assistance of an anaesthetic nurse who will provide you with support throughout the procedure. You will be kept constantly informed of what is happening whilst the procedure is progressing.
- Once the anaesthetist has identified the appropriate landmarks, an injection of local anaesthetic will be administered into the skin to numb the tissues prior to the insertion of the Spinal Needle.
A Spinal starts to work within 3-5 minutes. Initially you may feel a degree of warmth in your legs followed by pins and needles in one or both of your legs. You will be asked to lie flat as the spinal block continues to work. Following the loss of these sensations your legs will be “numb” to touch and after approximately 10 minutes you will be unable to move your legs. You will feel no pain below the waistline at this stage.
Whilst the anaesthetic is taking effect your vital signs, including blood pressure, will be monitored closely.
- Less risk of chest infections after surgery
- Excellent pain relief after surgery
- Less effect on the lungs
- Less Morphine related side effects (nausea and vomiting)
- Improved bowel recovery after bowel surgery
- Improved blood flow after vascular surgery
- Earlier return to drinking and eating after surgery
- Less risk of confusion after surgery in older people
- The risk of blood clots in the legs and lungs are reduced
- The risk of significant bleeding during surgery is reduced and therefore you are less likely to require a blood transfusion
- You will remain in full control of your own breathing
- You will not require as much strong pain relieving medicine in the first few hours after the operation
- You should have less sickness and drowsiness after the operation and may be able to eat and drink much sooner
- Orthopaedic surgery and any major surgery involving joints and the long bones
- General surgery including hernia repair and varicose veins
- Urological surgery including bladder operations, genital surgery and prostate surgery
- Gynaecology including bladder and vaginal repair
- Obstetric surgery for Caesarean Sections
- Vascular surgery including operations on major blood vessels
The numbness and weakness may take several hours to wear off. During this period of time the nurses who are involved in your recovery will take special care to protect the numb area from pressure and injury.
As the spinal wears off you may experience some tingling in the skin and you may initially require assistance with mobilising. Remember to ask for help. You can normally drink fluids within an hour of the completion of surgery and you may have a light diet.
Modern anaesthesia is generally very safe. Unfortunately with every anaesthetic technique, there is a possibility of unwanted side effects or complications. These may be unpleasant but can be treated and usually do not last long.
Common side effects of Spinal Anaesthesia are:
- Nausea and vomiting.
- Low blood pressure. This may make you feel faint or sick. It is easily treated through the administration of intravenous fluids and drugs to raise your blood pressure.
- Pruritus – itching is a common side effect of Morphine like drugs.
- Headache – there are multiple causes of mild headache including the surgery, the anaesthetic drugs and dehydration. If you have a severe headache after a spinal block, you may need a specific treatment to relieve the headache. Your anaesthetist will discuss this further with you.
- Pain, backache and/or bruising at injection site.
- Difficulty in passing urine. You may find it difficult to empty your bladder normally for as long as the spinal lasts. Your bladder function returns to normal after the spinal wears off. You may require an indwelling catheter in your bladder until the spinal wears off.
- Nerve damage - is a rare complication of Spinal Anaesthesia. Temporary loss of sensation, pins and needles and sometimes muscle weakness may last for a few days or even weeks. In most cases, there is a full recovery.
- Infection around the injection site.
- Cardiac arrest.