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This page provides general information about extreme lateral lumbar fusion and decompression (XLIF®).

Your neurosurgeon will discuss your particular procedure with you in detail. It is intended for use by patients (or their families or carers) referred to our service who may be offered this procedure. It is not intended to replace discussion with your consultant.

If you have any questions please do not hesitate to contact a member of the team caring for you.

If you have existing medical conditions, such as high blood pressure or diabetes, you may like to visit your GP practice to make sure that you are as fit as possible for your surgery. Make sure you arrange your domestic and social situation so that it will be possible and comfortable for you to go home at the correct time. For instance:

  • Arrange for somebody to collect you on discharge
  • Make sure you have shopped for adequate food supplies for when you get home
  • Tidy your house so you do not need to do housework when you get home
  • Ensure you have a supply of simple pain killers available at home, such as paracetamol
  • If you think you will need some social support after discharge please speak to your GP and let us know as soon as possible

We will:

  • Arrange a pre-assessment check to make sure you are fit for an anaesthetic
  • Organise appropriate scans or x-rays for your operation
  • Write to you to let you know when your operation will be
  • Answer any questions you may have about your operation

The extreme lateral interbody fusion, known as a XLIF®, is a minimally invasive (keyhole) procedure used in spinal surgery for more than 10 years. This is a new intervention in UCLH. The procedure, however, has been performed for more than 10 years.

Spinal interbody fusion means that two or more levels of spinal bones are permanently fixed together to prevent them from moving. This may be done in conjunction with other spinal procedures like decompression or posterior fixation that can be undertaken as a second stage procedure In a XLIF® procedure, the incision for surgery is made along the side of your torso.


The main aim is to help reduce leg pain (radiculopathy) caused by compression of the nerve roots and stabilise the spine An XLIF® approach means that the back muscles (posterior spinal muscles) which are very important for spinal function remain intact. This helps reduce pain after surgery and improve recovery.

This particular procedure reduces the risks associated with front and back approaches which are described in the section on alternatives. In general there is less blood loss and an earlier return to normal activities with this type of surgery. Where more than one spinal level is involved (such as spinal curvature) access is easier and safer.

This procedure is performed under a general anaesthetic; this means that you will be unconscious and unaware throughout. The nurse caring for you will accompany you to the operating theatre where you will be met by theatre staff. The anaesthetic will commence in an anaesthetic room adjacent to the operating room. You will be positioned on your side for surgery.

The skin over the operative site is carefully cleaned and one or two small incisions (cuts) are made. More than one point of the spine may be operated on through these cuts. Throughout the procedure X-rays are used to guide the surgeon to the correct site.

The specialised XLIF® instruments are used at this time. The muscle is separated gently to allow the surgeon to access the spine. The affected part of the spine (vertebral disc) is then removed. An implant is then placed to make the spine strong and stable – the implant also recreates the size of the disc. This means that the spine will be able to support the normal activity of daily life. Artificial bone graft (a pharmacy produced bone substitute) is then packed into a small device known as a ‘cage’.

During the procedure the nerves arising from the spine are monitored to avoid injury. When the surgeon is satisfied with the placement of the implants, the surgical instruments are removed and the wound is closed with stitches or clips.

The surgery is performed under general anaesthetic and takes between 2-3 hours. The bone in the cage will grow over the coming months, forming a bridge between the two bones. This will connect or ‘fuse’ the vertebrae together, preventing further irritation to the nerves. Achieving a solid bony fusion is a slow process and occurs between 6 and 12 months after surgery.

All procedures and treatments carry risks and we will talk to you in detail about the risks of this procedure. The risks of XLIF® surgery are the same as those of any spinal fusion procedure, these include:

  • Infection of the wound. We take all precautions to prevent infections. You will be given antibiotics during the operation and afterwards.
  • Metalwork failure. This means there is a problem with the implants used. This is rare and will require further surgery.
  • Nerve injury. The spinal nerves which supplies the legs (lumbar plexus) may be damaged causing pain, which may be permanent. Injury can also cause weakness, numbness and occasionally pain in the nerves in this area. This can be due to bruising of the nerve which recovers after a short period of time. If a transection (cutting) of the nerve occurs recovery is unlikely. This is very rare ( less than 1%). 
  • Bowel vessel injury. The bowel and vessels may be injured during the procedure. This is very rare but can have serious consequences. The use of specialised XLIF® instruments, special training and the use of X-rays help reduce this risk to minimum.

Additionally, there is a risk of damage to the psoas muscle; this is the large muscle on either side of the spine. This can cause thigh pain and weakness when the hip is flexed, but this is usually short-term.

During spinal procedures many x-rays are taken to help guide the surgeon. Our state of the art imaging equipment ensures the radiation dose is as low as possible.

X-rays are harmful to unborn babies, female patients should tell their consultant if there is a possibility they may be pregnant.

The aim of this procedure is to relieve the pressure on the nerves (decompression). This is done by inserting a cage from the side of the spine, lifting the spinal bones apart, so that they are no longer ‘squashing’ the nerves at the back – this is known as an indirect decompression. In some cases, this ‘indirect decompression’ does not relieve enough pressure on the nerves and a further procedure from the back will need to be performed.

This second procedure is done so that the nerves are fully ‘freed up’ and is known as a posterior decompression and fusion. This means that you may have to have two procedures, and therefore two anaesthetics, rather than one.

The decision to go ahead with surgery or this particular procedure is entirely yours and will not compromise your care. Your consultant will talk to you about all available options.

Your consultant will discuss all alternative treatments and their benefits and risks with you.

The alternative to surgical treatment includes physiotherapy and injections into the painful areas. Other conservative approaches include surveillance with regular review and assessment and referral for physiotherapy and pain management. Your GP may prescribe pain-relieving medicines.

Adopting a healthy lifestyle with regular exercise, combined with diet and weight control is also another treatment approach to help your symptoms. Although some patients may respond to these measures and remain stable, some patients may still suffer progression of their symptoms. Other spinal interbody fusion techniques include:

  • Posterior Lumbar Interbody Fusion (PLIF): A PLIF means that the surgery is performed through an incision on the back. The implants which are used to stabilise the spine are placed on both sides of the spine.
  • Transforaminal Lumbar Interbody Fusion (TLIF): This is similar to PLIF but the implant is placed from one side only. This procedure causes less disruption to the muscles of the back.
  • Anterior Lumbar Interbody Fusion (ALIF): An ALIF means that the approach to the spine in made through the abdomen. This approach requires delicate manipulation (moving) of major blood vessels in front of the spine. However, the muscles in the back are left intact. In men an anterior approach carries a risk of nerve damage causing retrograde ejaculation.

We want to involve you in all the decisions about your care and treatment. If you decide to go ahead with treatment, by law we must ask for your consent and will ask you to sign a consent form. This confirms that you agree to have the procedure and understand what it involves. Staff will explain all the benefits, risks and alternatives before they ask you to sign a consent form.

If you are unsure about any aspect of your proposed treatment, please don’t hesitate to speak with a senior member of staff again.

Immediately after surgery you will be transferred to the recovery room for close monitoring. Once you have recovered from the anaesthetic and it is safe to do so you will be transferred back to your ward.

You will be prescribed regular pain relieving medicine. Please tell your nurse if you still have pain; we want you to be comfortable and reduce the risk of complications. You may still experience discomfort on movement, this is normal. We will assess the strength in your legs regularly to check for complications.

You will be able to mobilise immediately after surgery, usually the same day, and this is encouraged. Physiotherapy advice on how to care for your back in the future, including how to strengthen your back muscles and how to lift correctly will be given.

Before going home, you will be given an information booklet concerning your wound care.

On the journey home, you may find sitting in a car seat for long periods uncomfortable, so if you have a long journey home, try to plan regular stops so you can stand up and walk about.

You may find that you need to take regular painkillers for two to three weeks after the operation to ease the pain at the wound site. This should improve over time and you can cut down the number of tablets you take.

It is normal to feel tired after an operation. Try to do a little regular activity such as walking, rather than attempting to do too much at once.

Avoid strenuous exercises and activities until you have been reviewed in clinic six to eight weeks after discharge. It is normal to experience some leg pain and/or back pain after surgery. This usually settles with pain killers, rest and time. However, if you develop:

  • new-onset symptoms such as leg weakness or numbness
  • new difficulty with bladder or bowel control, or problems with sexual function
  • any wound problems such as redness, excessive soreness, or wound discharge

Contact your consultant or clinical nurse specialist via their secretary (during working hours). The ward, your GP or local accident and emergency department can give help and information at other times.

You can start driving again when you feel comfortable and confident enough to operate a vehicle safely and you are confident you are in full control of the vehicle. This varies between individuals after surgery. Contact the DVLA and your insurance company for further information about driving restrictions.

Please discuss your return to work, daily or leisure activities with your surgeon, specialist nurse or therapist. Most people will return to work six weeks after the operation, depending on their work. You may need to contact your Occupational Health Department if you need to make adjustments to your working arrangements, such as different seating for a desk job or if you are unable to do heavy manual work.

Your surgeon will write to your GP to inform them of the operation you have had. You will be asked to attend an outpatient clinic at the hospital six to eight weeks after surgery so that we can check on your progress.

UCLH cannot accept responsibility for information provided by other organisations.

Victor Horsley Neurosurgery Department
National Hospital for Neurology and Neurosurgery
Queen Square, London

Switchboard: 0845 155 5000 / 020 3456 7890
Secretary’s direct line: 020 3448 3568/3150/3395
Fax: 0203 3448 3340

Page last updated: 16 May 2024

Review due: 01 November 2024