Overview

Acute pain is when you hurt yourself, and the pain warns you to do something about the pain. It doesn’t usually last very long. Sometimes our pain systems become oversensitive and pain continues. If pain continues in this way for more than 3 months, it is called chronic or long-term pain. Medicines that work for acute pain are often less effective for chronic pain.

People who are in pain tend to do less physically and socially. This often makes chronic pain worse as people become less fit and have less enjoyment in their lives. Other side effects of chronic pain include:

• poor sleep
• tiredness (fatigue)
• boredom
• depression
• anxiety

It is important to recognise and address all of these problems associated with chronic pain, and not focus just on the pain.

Spinal cord stimulation might reduce the intensity of the pain, but it cannot resolve the pain completely, and is not a cure. It is most effective when combined with other treatments that deal with the effects pain is having on your quality of life, emotional well-being and physical functioning. It is only a part of a treatment strategy, and not a complete treatment on its own.

Spinal cord stimulators

A spinal cord stimulator system is made up of an implanted battery which is attached to a small lead. The leads are programmed to create a small electrical field. The leads are put next to a nerve, and the electrical field can result in a reduction of a specific type of pain. When the system has been surgically implanted, it is controlled by the patient using a handheld controller. Spinal cord stimulation is sometimes called neuromodulation.

For some patients, low-frequency stimulation, where you feel some tingling (paraesthesia) will be used. For other patients, higher-frequency stimulation, where you cannot feel anything, will be the best treatment for the pain. The type of stimulation is selected by the pain consultant, and depends on the pain condition you have.

When a spinal cord stimulator is suggested

A spinal cord stimulator can only treat certain types of pain. We recommend spinal cord stimulation for these conditions.

• Pain which is caused by an injury to the nerves (neuropathic), rather than pain caused by damage to the other tissues, such as the joints and muscles.
• Failed back surgery syndrome, when patients have neuropathic pain, rather than mechanical pain.
• Complex regional pain syndrome.
• Severe chronic pain that is limiting daily life, where all reasonable therapies (such as painkillers and physiotherapy) haven’t worked.

A spinal cord stimulator cannot be used as a stand-alone treatment for chronic pain. Patients must engage with all elements of the treatment pathway to have the best chance of relieving their pain.

Patients who are being considered for a spinal cord stimulator are assessed by a multidisciplinary team (MDT). This team includes doctors, clinical nurse specialists (CNSs), physiotherapists, occupational therapists and psychologists.

When spinal cord stimulation is not suitable

Spinal cord stimulation is not suitable for everyone. These are some of the situations where this treatment might not be offered to you.

• Mechanical pain, for example, pain due to arthritis or spinal instability.
• Significant pain beyond the area that a spinal cord stimulation system can cover, such as widespread pain syndromes (more than a single area, such as lower back and neck at the same time).
• Physical problems that mean it is not possible to fit the device safely. For example, major spinal conditions, extensive spinal metalwork, or extensive spinal scar tissue.
• A body mass index (BMI) of below 18, or above 35, as this results in an increased risk of complications. Calculate your BMI.
• An active infective illness.
• Postural tachycardia syndrome (PoTS). This is an abnormal increase in heart rate after sitting up or standing.
• Some chronic illnesses, for example; multiple sclerosis (MS), or severe respiratory disease.
• Mental health conditions which might stop you being able to effectively manage the device, or manage the treatment care pathway.
• Excessive use of alcohol, prescription medicines, or recreational drugs.
• Some memory or cognitive difficulties might stop you being able to manage the device or give permission (consent) for the treatment. You must be able to manage the technical demands of the equipment.
• If you have a metal allergy, such as a nickel allergy, as some devices contain nickel.
• People under 18 years of age.

Traditional therapies (such as painkillers and physiotherapy) to manage the pain must have been tried before a spinal cord stimulator is considered.

This would form part of the decision as to which type of device could be used.

You must be willing to stop taking (or reduce) excessive pain medicines. Patients on high doses (equivalent to 100mg of oral (by mouth) morphine) of opioid medicine would have a less effective response to spinal cord stimulation. You might be asked to reduce to a specific target dose, or stop opioid medicine completely, for at least 6 weeks before a trial of spinal cord stimulation. The team will support you and your GP with this.

Spinal cord stimulation treatment pathway

Neuromodulation clinic assessment

A pain-management consultant will assess if your pain is suitable to be treated with spinal cord stimulation.

Psychology and physiotherapy appointment

This is a joint assessment where you will be seen by a psychologist and a physiotherapist. We look at how the pain is affecting your quality of life, including your:

• physical function
• level of activity
• emotional wellbeing
• relationships
• family life
• sleep
• work
• hobbies

We will talk to you about your expectations of spinal cord stimulation, and how you hope the treatment package will help you. We will also discuss how you might feel if the trial doesn’t help.

Consenting to spinal cord stimulation

After completion of the pre-implant programme or technology day, you will have another appointment with a pain management consultant to discuss whether to proceed with a trial of spinal cord stimulation.

If you and the consultant decide a trial is the best treatment for you, you will sign the consent form and have an anaesthetic pre-assessment appointment. This appointment can take up to 3 hours, including waiting time.

Read more about our consent process.

Spinal cord stimulator trial

A trial of spinal cord stimulation is done before considering a permanent implant. This is because not all patients' pain responds to spinal cord stimulation.

During a spinal cord stimulator trial, the leads are implanted, but the battery is not. The trial usually lasts for 14 days.

The trial is normally done as a day-case procedure (under sedation) at Guy’s Hospital or in the pain procedure room (under local anaesthetic) in the pain management department at St Thomas’ Hospital.

The spinal cord stimulation leads are carefully positioned and then attached to an external handheld controller that allows you to control the stimulation. A pain management nurse will make sure you are confident using the equipment before you leave hospital.

You will come back to the pain management centre in the middle of the trial for a review with the CNS and the consultant. It is important that you contact us if you have any concerns or problems during the trial.

Outcomes from the trial

If the spinal cord stimulator is not successful

Spinal cord stimulation trials are only successful for 7 out of 10 people. For the trial to be considered a success, the device must have a significant impact on your quality of life and on the intensity of your pain. If the trial results in a moderate impact, it is not considered successful. This is because the amount of pain relief provided by the spinal cord stimulator will reduce over time.

If your pain does not respond to spinal cord stimulation, your care will be transferred back to your referring consultant. We hope that the 2 week pre-implant pain management programme continues to provide patients with useful skills which help them to manage the impact that pain has on their quality of life, even if the trial is not successful.

If you receive the permanent implant

If the trial is successful, another day surgery procedure is needed to fully implant the device. The first stage of this procedure is placement of the stimulating lead in your spine, similar to the trial.

The second stage of the permanent implant is inserting the battery. This is done under deep sedation or general anaesthetic. You will need to discuss the position of the battery with your consultant before the procedure. The position of the battery is different for each patient. It will usually be in your back, but can also be in your buttock (bum) or tummy (abdomen).

A small cut (incision) in your skin is required to insert the battery. You can usually leave hospital within a few hours of the procedure, depending on how long the doctor or nurse wants you to stay to recover.

If you receive a full implant, it is important that you continue to use the pain management strategies you’ve learnt, alongside the device. This will enable you to get the best possible benefit from the device.

Risks of spinal cord stimulation

• Painful battery or connection site. If severe, more surgery or removal might be advised.
• Infection occurs in less than 1 in 20 people. If this happens, the whole system might need to be removed.
• Having the stimulator put in could cause bleeding which might lead to bruising and, in rare cases, might need more surgery.
• The dura (protective layer around the spinal cord) can be punctured during the procedure. This can result in a severe headache which might need treatment with a spinal injection if it does not improve within days.
• The leads might move or stop working, and you might need more surgery to correct them.
• Unpleasant sensation from the stimulation can occur. This might not respond to adjustments and could mean that the device is removed.
• Stimulation felt outside of the painful area is common, but only a problem if unpleasant.
• Failure to capture the area of pain, or no pain relief. This can lead to revision surgery to move the leads, or removal of the device.
• Allergic reaction leading to removal of the stimulator.
• Decrease in pain relief with time.
• Nerve damage leading to nerve pain, numbness and weakness. This might be temporary or permanent.
• Paralysis. This is extremely rare and affects 2 in a million patients.
• A granuloma (scar tissue) could form on the leads, at the wound site or at the battery site.

Living with a spinal cord stimulator

• Some physical activities might need to be avoided during the first 12 weeks, to help prevent the leads moving. Your physiotherapist will discuss this with you.
• If you need surgery in the future, you must tell your surgeon and anaesthetist that you have a spinal cord stimulation device as they will need to use a different type of instrument, called a bipolar diathermy.
• Depending on the type of device chosen, it might not be possible for you to have MRI scans. CT scans and X-rays are allowed.
• Stimulator systems can activate airport detectors and anti-theft devices in shops. These, along with strong magnets, might turn your stimulator off and affect your battery.
• You should not drive with the device on if you have low-frequency stimulation, as sudden increases in sensed stimulation might interfere with driving.

Who is responsible for your care

After your permanent implant, the pain management centre will be responsible for your spinal cord stimulation system. The CNSs will continue to provide ongoing support and advice. You will have appointments each year, on the phone or in the clinic. Appointments can be arranged for review or programming in between this, if needed.

Patient responsibilities during the spinal cord stimulator pathway

You need to tell us if any of these changes occur while you are on the spinal cord stimulator pathway:

• significant changes to your physical health, such as a new diagnosis or a change in your physical function
• a change in your mental health
• you are having any treatment, such as surgery, that might affect your pain condition