Spondylolisthesis Information

Introduction 
 
Lumbar spondylolisthesis describes a condition where one vertebral body slips forwards, or subluxes, on another vertebral body.  The most commonly affected levels are L5/S1 and L4/5, however, other spinal levels can also be affected.  As one vertebral body slides forward on the other, the intervertebral disc in between the two bodies is uncovered and can press on spinal nerves.  The intervening disc commonly shows collapse and degeneration.  
 
If the spondylolisthesis is mobile, or increases with bending forwards and backwards, it is termed unstable.  This is commonly associated with back pain.  If there is no movement it is called a stable spondylolisthesis. 
 
The slipping forward of one vertebral body on another, and the uncovering of disc material, can narrow the spaces where the nerves in the lumbar spine are located.  This can cause additional symptoms in the legs, including pain and sciatica.  For more information about spondylolisthesis watch the video below.  

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There are different types of spondylolisthesis.  Routine spinal imaging easily differentiates one type from another.  Each type has its own cause and treatment options:

1. Isthmic – Isthmic, or lytic, spondylolisthesis, is due to a deformity or fracture (commonly due to fatigue) in a part of bone called the pars interarticularis.  This leads to what is called pars defects in the bony ring (neural arch) at the back of the spine.  These bony defects destabilise the spine.  Over time the vertebral body above slides forwards on the vertebral body below.  This commonly occurs in younger people including athletes. 
2. Degenerative – This is due to wearing out or degeneration of the spine and is more commonly seen in older people.  There is usually no bony defect, or pars defect, in this type of spondylolisthesis.  Degenerative changes in the intervertebral disc, loss of disc height, ligament laxity and facet joint arthritis lead to instability at the effected level and the slipping forward of one vertebral body.  L4/5 is the most common level affected, although other levels can also be affected.
3. Dysplastic – This is a rare congenital condition where there is a defect in the bony arch at the back of the spine.  Most commonly associated with spina bifida or other congenital abnormalities of the spine.
4. Traumatic – Unstable slipping of one vertebral body due to a fracture in one of the bones of the spine.  This type is always associated with traumatic injury to the spine.  
5. Pathological – Fortunately rare, this type of spondylolisthesis is caused by damage to the bone in the spine due to destructive processes such as  infection or cancer. The damage to the bone causes the spine to be unstable leading to the spondylolisthesis.  
6. Iatrogenic – Due to previous spine surgery which has destabilised the spine.  Can be seen after laminectomy where the spinal elements at the back of the spine have been removed. This is an unfortunate but well recognised complication of laminectomy surgery.  

The severity of spondylolisthesis is graded according to how far one vertebral body slides forward on the other.

• Grade 1:  less than 25% slip
• Grade 2: 25 – 50% slip
• Grade 3: 50 – 75% slip
• Grade 4: 75 – complete slip

 
Not all patients will be symptomatic from spondylolisthesis and surgery is only indicated for severe symptoms.  In approximately 30% of spondylolisthesis patients, the degree of slip will progress, so it is important to monitor all patients with MRI scans even if they are asymptomatic. 
 
Symptoms 

Spondylolisthesis may be asymptomatic.  In these patients monitoring with MRI scans or x-rays is important to determine if the degree of slip is getting worse.  In patients without symptoms no treatment is generally needed.   However, in these patients, physiotherapy to strengthen core and spinal muscles, as well as weight loss, are important in order to prevent or delay progression. 
 
When symptomatic, spondylolisthesis can cause back pain and also pain due to compression of the nerves, termed sciatica or radiculopathy.
 
Lower back pain can occur due to spinal instability in spondylolisthesis.  This pain tends to worse with movements such as bending forward, which leads to exaggeration of the slip.  Back pain can also come from the adjacent intervertebral disc, termed discogenic pain.   Back pain can also come from compensatory changes or arthritic changes in the following structures:

• Facet joints
• Periosteum/bone
• Ligaments
• Paraspinal musculature and fascia
• Nerve roots

 
In addition to back pain, lumbar spondylolisthesis is associated with symptoms of nerve compression.  The slipping forward of one vertebral body on another, and the uncovering of disc material, can narrow the spaces where the nerves in the lumbar spine are located, causing symptoms such as:

• Leg pain (sciatica)
• Neurorgenic claudication (pain in backs of calves and legs with walking)
• Loss of feeling in the legs (numbness or parasthesias)
• Leg or foot weakness (for example foot drop)
• Problems with walking  (gait disturbance)
• Troubles with bladder and bowel function.

 
Spondylolisthesis, particularly the degenerative type, can also lead to lumbar canal stenosis, or narrowing of the entire spinal canal at the affected level.  Lumbar canal stenosis is narrowing or constriction of the central canal leading to compression of multiple nerves in the lumbar spine. Lumbar canal stenosis causes a syndrome known as neurogenic claudication, which is pain in the backs of the calves and legs, that is often worse with walking and standing, and relieved by sitting down. 

Less commonly, but more importantly, spondylolisthesis can cause cauda equina syndrome.  This is where multiple nerve roots are severely compressed causing pain, leg weakness, urinary and bowel problems, and anaesthesia around the buttock and genital area. If you have symptoms of cauda equina you should seek medical attention urgently at you local hospital.
 
When symptoms of nerve compression are present and severe, surgical intervention is usually indicated for spondylolisthesis. 

Investigations 

Following the initial clinical assessment, it is usual for some type of radiological investigation to be organised in order to look in more detail at the spondylolisthesis. Radiological investigations include: 

• MRI (Note if you are able to have an MRI, this is the best test to assess lumbar spondylosis and canal stenosis)
• CT
• X-ray
• Dynamic x-ray
• Bone scan including SPECT CT

 
Treatments 

Unless you have severe pain or significant neurological deficits, such as lower limb weakness, or bowel or bladder dysfunction, the initial treatments for lumbar spondylolisthesis are conservative non-operative therapies.   These treatments include:

• Analgesics (pain medication)
• Non-steroidal anti-inflammatory drugs (NSAIDs)
• Physiotherapy
• Steroidal injection therapies
• Behaviour modification - e.g. avoiding heavy lifting
• Bracing
• Pilates
• Hydrotherapy
• Swimming
• Weight loss - this is important as extra weight places more stress on the spine contributing to back pain.  
• Strengthening exercises to strengthen core and paraspinal muscles - this will help provide extra stability to the spine reducing pain.
• Pain management 

Following exhaustion of non-operative measures, or when the degree of nerve compression is severe, surgery is often indicated for lumbar spondylolisthesis. 
 
Where symptoms of nerve compression predominate, namely, radiculopathy or neurogenic claudication, the goal of intervention is to decompress the nerves, relieving the pressure on them.  Relieving the pressure on the nerves reliably improves the symptoms of pain in the legs.  In some patients with a small degenerative spondylolisthesis, this can be done with a small procedure, such as a laminectomy or minimally invasive lumbar decompression, without the need for a fusion procedure.
 
Many patients with spondylisthesis will require a spinal fusion surgery to prevent spinal instability or worsening of the slip post-operatively.  The goals of lumbar spinal fusion surgery are to:
 
1. Decompress the nerves, relieving the pressure on them, improving symptoms of pain in the legs
2. Stabilise the spine at the level where the spondylolisthesis is present, reducing back pain and instabililty
3. Restore normal spinal alignment thereby reducing pain, and improving overall spinal health and well being. 
 
The exact type of spine fusion required will vary from patient to patient.  Dr Oehme will advise which procedure is best for your condition.  
 
See our spinal surgery procedures pages for more information about spine surgery for spondylolisthesis,  including information about spine fusion, ALIF, TLIF, PLIF and XLIF.