What is Spinal Cord Stimulation?
You have probably had many treatments for your pain, most of which will have been of little or no long-term help. Spinal cord stimulation works by targeting the region of the spinal cord involved in the transmission and processing of pain. We introduce a small amount of electrical current to the back of the spinal cord, which helps to mask the pain that you are feeling. It also increases the blood flow to the heart and legs, often helping patients with angina and peripheral vascular disease.
Who might be suitable for spinal cord stimulation?
A number of painful conditions can be treated using spinal cord stimulation.
Patients with the following conditions who have failed all standard medical therapies may benefit:
- Previous spinal surgery with ongoing leg pain
- Complex regional pain syndromes (neuropathic pain, causalgia, reflex sympathetic dystrophy)
- Nerve injuries (from trauma or previous surgery)
- Angina (ischaemic heart disease)
- Peripheral vascular disease
What are the reasons for surgery?
When medications and other treatments are no longer working well or their side effects are to severe, spinal cord stimulation may be of value.
What are the alternatives to surgery?
A number of medications may be useful for pain. These include the standard opioid and non-opioid analgesic agents, membrane stabilising agents and anticonvulsants, as well as the most recent agent to be released- Pregabalin. Special medical treatments such as Ketamine infusions, local nerve and joint blocks, as well as other surgical options such as spinal decompression or fusion should also be considered. It is critical that you have been assessed by a pain specialist and psychologist before contemplating spinal cord stimulation.
What do you need to tell the doctor before surgery?
It is important that you tell your surgeon if you:
- Have blood clotting or bleeding problems
- Have ever had blood clots in your legs (DVT or deep venous thrombosis) or lungs (pulmonary emboli)
- Are taking aspirin, warfarin, or anything else (even some herbal supplements) that might thin your blood
- Have high blood pressure
- Have any allergies
- Have any other health problems
What happens before surgery?
We will send you pain charts to fill in.
The first chart is a body map. You should shade in the areas of your body that are affected with pain.
The second chart is a pain diary. Fill this in over a period of a week or so. If your pain varies over the day, do a few scores per day, but if your pain tends to stay the same over the day a daily score will be enough.
The third chart is called McGill Questionnaire. This chart does not rely on numbers but helps you to describe your pain to us. As it states on the form, not every group of words may apply to you. Pick the words that best describe your pain.
How is spinal cord stimulation performed?
This is usually done in 2 stages, several days apart. Your admission will be for approximately 7-10 days.
Stage 1 (insertion of the electrode)
You will be taken to the operating theatre, given a general anaesthetic (ie. you will be asleep), and your skin cleaned with antiseptic. Local anaesthetic will be injected and you will be lightly sedated. A small incision will be made in your back or neck, and a window of bone shaved off the back of your spine to expose the lining over the spinal cord. An electrode that looks like a miniature paddle will then be carefully placed over the back of your spinal cord. Stimulation will then be undertaken to be sure that the electrode is in a satisfactory position. Temporary extension wires will then be connected to the electrode, and these will be brought out through the skin away from your incision.
After stage 1
One or two wires will be coming through the skin. We will attach these wires to a hand-held external stimulator and test the effects of stimulation for several days. This gives us time to find the best settings for you.
Throughout your admission you will frequently be asked to score and describe your pain. This will allow us to know if the treatment is working or not. It also gives time for you to decide whether or not you are happy with the amount of pain relief you are getting.
Stage 2 (battery insertion)
If you are happy with the amount of pain relief obtained during the trial period, we will carry out the second stage several days later. Again, this is performed under general anaesthetic. The temporary external wires are removed and the electrodes connected to permanent extension wires which are, in turn, connected to a battery (‘implantable pulse generator’ or ‘IPG’). The battery is normally implanted under the skin in your abdomen, back or buttock. Your battery will be programmed over the next couple of days so that the stimulation you receive will be best for you.
What happens next?
You should be ready for discharge from hospital 1-2 days after the second operation. Your GP should check your wounds 4 days after discharge. We will advise you when to have your stitches removed at your GP's surgery or by the Precision Neurosurgery Practice Nurse. You will need to take it easy for 6 weeks.
You should do an hour of gentle exercise, such as walking, every day. You should not sign or witness any legal documents until you have been seen by your GP. You will be reviewed after 6-8 weeks by your neurosurgeon. You should not drive a motor vehicle or operate heavy machinery your neurosurgeon gives you the go ahead.
You will also be given some detailed information about things you must avoid, such as metal detectors at airports. It is critical that you read such information thoroughly. There may be some other restrictions on what you can and cannot do, and these will be discussed with you before surgery or during your hospital stay.
How successful is spinal cord stimulation for pain?
Spinal cord stimulation helps up to 60-70% of the patients selected for treatment. The rate of reduction in pain varies from patient to patient. On average, pain scores are reduced by 50%. For example if a patient had a pain score of 10/10 we would be able to reduce it to 5/10. We are particularly successful with getting rid of the burning sensation aspect of the pain in the majority of patients. Leg pain generally responds better than back pain.
What are the specific risks of this type of surgery?
As with all types of surgery, there is a small chance of complications.
- There is a small risk of infection (3%)
- There could be movement of the electrode, and it may need to be replaced in a separate procedure
- Failure of the stimulator
- Small risk of bleeding
- The chance of making your pain worse, rather than better in less than 1%
Spinal fluid leak is very uncommon
- Paraplegia or quadriplegia, incontinence or impotence are rare
- The risk of death is extremely small (less than 1 in 30,000)
What are the risks of anaesthesia and the general risks of surgery?
- Significant scarring (‘keloid’)
- Wound breakdown
- Drug allergies
- DVT (‘economy class syndrome’)
- Pulmonary embolism (blood clot in lungs)
- Chest and urinary tract infections
- Pressure injuries to nerves in arms and legs
- Eye or teeth injuries
- Myocardial infarction (‘heart attack’)
- Loss of life
- Other rare complications
What happens down the track?
We will keep in close contact with you after your discharge from hospital. You will probably require repeated programming adjustments over the first few months to optimise your pain relief. Your pain medications can be reduced as tolerated.
The battery life will vary depending on your stimulation settings (on average the rechargeable batteries used will last at least 5 or 10 years). We will need to see you at least once a year to check the battery and ensure you have continued pain relief.
How long will the benefits last?
This will vary from patient to patient. Typically, patients obtain a benefit for several years or longer. The benefit may gradually decreases with time and so the stimulator settings may be increased to compensate for this. Some patients may benefit from repeat surgery if the benefits drop off.
What should you notify your doctor of after surgery?
- Swelling or infection of the wounds
- Weakness or numbness in the arms or legs
- Worsening pain
- Any other concerns
What are the costs of surgery?
Private patients undergoing surgery will generally have some out-of-pocket expenses.
A quotation for surgery will be issued, however this is an estimate only. The final amount charged may vary with the eventual procedure undertaken, operative findings, technical issues etc. Patients are advised to consult with their Private Health Insurance provider and Medicare to determine the extent of out-of-pocket expenses.
Separate accounts will be rendered by the anaesthetist and sometimes the assistant, and hospital bed excess charges may apply. Medical expenses may be tax deductible (you should ask your accountant).
You should fully understand the costs involved with surgery before going ahead, and should discuss any queries with your surgeon.
What is the consent process?
You will be asked to sign a consent form before surgery. This form confirms that you understand all of the treatment options, as well as the risks and potential benefits of surgery. If you are unsure, you should ask for further information and only sign the form when you are completely satisfied.