Isthmic Spondylolisthesis

What Is Spondylolisthesis?

The term spondylolisthesis describes the forward slippage of a vertebral body in relation to the one beneath it. Although the condition may develop at higher levels in the spine, it most commonly occurs in the lumbosacral level, frequently at the junction between L5 and S1.

Spondylolisthesis can be categorised into 4 different types:

  • Dysplastic Spondylolisthesis – a birth defect in part of the vertebra which causes the vertebra to slip forward.
  • Isthmic Spondylolisthesis – typically a result of repetitive trauma to the spine, this occurs more frequently in athletes or people engaged in sporting activities such as gymnastics, football or weight lifting etc.
  • Traumatic – a sudden injury or trauma to the spine such as a fracture, this is often the result of an accident.
  • Pathologic – a bone abnormality which may be caused by a tumour - pathologic spondylolisthesis.

gymnastics isthmic spondylolisthesis


Spondylolisthesis is typically classified into four different grades based on the degree of the slippage.

Grade 1 – less than 25%

Grade 2 – 25% to 50%

Grade 3 – 50% to 75%

Grade 4 – 75% to 100%

Isthmic Spondylolisthesis

This type of spondylolisthesis usually occurs due to trauma such as a stress fracture, to the pars interarticularis – this describes a bony structure which connects the superior and inferior facet joints to the spinal vertebrae.  Isthmic Spondylolisthesis refers to a defect or lesion in the pars interarticularis which over time can results in vertebral slippage, most commonly between L5 – S1, closely followed by L4 – 5. The pars interarticularis are subject to a lot of force during every movement, this is significantly increased during vigorous physical activity, any lesions or trauma to the pars interarticularis can potentially cause unilateral or bilateral instability, resulting in vertebral slippage or disconnection.

Symptoms of Isthmic Spondylolisthesis

In some cases, there may be no visible signs of isthmic spondylolisthesis, however in the majority of cases chronic pain or discomfort is present. Some may only suffer from mild symptoms, whereas others may experience incapacitating symptoms as a result of; neurogenic claudication (which may be a result of spinal stenosis), radiculopathy typically caused by nerve compression of the exiting L5 nerve root in the L5 – S1 foramen, or from severe mechanical pain.

General symptoms may include:

  • Lower back pain, often of a mechanical nature
  • Pain in the thighs or buttocks
  • Pain numbness, weakness or tingling in the legs indicative of neurological symptoms
  • Depressed deep tendon reflexes
  • Positive straight leg test

Acute isthmic spondylolisthesis may present with loss of bladder and bowel function and paralysis (Cauda Equina) this is however extremely rare as slippage rarely progresses beyond Grade 2 level.


A full medical history with a physical examination is typically the first point of diagnosis. During diagnosis it is important to rule out any red flags such as tumour or infection. X-Ray is particular useful in the evaluation of the extent of the slippage and CT or MRI scans may be helpful in determining any damage to nearby soft tissue structures or nerve compression.


Initially Isthmic Spondylolisthesis should be managed conservatively.

Pain Relief Medication

Over the counter pain relief medication including analgesics and anti-inflammatories such as ibuprofen can help to reduce pain and inflammation. Stronger prescription pain relief medication may be prescribed in cases of severe pain.


A physiotherapist can offer hands on manipulation as well as a number of targeted stretches and exercises to help relieve painful symptoms. Physiotherapy is also useful for teaching specific strengthening exercises for the core region helping to increase the range of motion from the lower back through to the legs.

Epidural Steroid Injections

In the case of suspected nerve compression, epidural steroid injections may provide temporary relief from painful symptoms.


In cases of confirmed diagnosis of nerve compression or irritation, decompression surgery may be an option – the exact surgical procedure would depend on the extent of the slippage and any damage caused by it.  In some cases, the slipped vertebrae may be fused to a neighbouring vertebra using metal screws or rods and in some cases bone grafting.

How We Can Help

The Pain Management clinic consists of a multidisciplinary team of pain management consultants, physiotherapists, psychologists as well as other health care professionals, which work together to provide those suffering from chronic pain conditions with individualised treatment plans.

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