SPINAL CONDITIONS

Pars fracture and Spondylolisthesis

Pars fracture

A pars fracture is a bony defect in a bit of bone on the lower back called the ‘pars interarticularis’. A pars fracture is also called a spondylolysis. The pars interarticularis is a part of a lamina. The lamina is the bony arch that forms the back part of a vertebra. 

A pars fracture is a stress fracture that occurs during the teenage growth spurt. The fracture occurs as the pars interarticularis gets very thin when we are going through a period of rapid growth. This condition most commonly presents with back pain in teenagers bought on by exercise, typically exercise involving repetitive extension (arching) of the lower back. Pars fractures occur in approximately 6-8% of teenagers, though the incidence is much higher in young sportsmen and women. There is an increased risk with sports that involve a lot of arching of the lower back, such as gymnastics, butterfly swimming, diving, and fast cricket bowling. A pars fracture usually occurs at the L5 level in the lower back. A pars fracture can progress to a spondylolisthesis if it does not heal.

Diagnosis

A pars defect can be diagnosed by X-ray, MRI or CT scans. CT scans give a very clear image of the bony anatomy and of the fracture defect. Pars fractures are seen slightly less clearly on MRI scans, but MRI scans do show the inflammation in the bone that comes with an acute bony injury which is not visible on CT. Usually MRI is the first investigation that we carry out, though some patients will need to have a CT scan as well.

Treatment of pars fractures

The initial management of a pars fracture is a period of rest and complete abstinence from all sport and physical exertion for at least 2-months. For some patients this may also entail having to wear a brace. This period of rest is followed by trunk and abdominal strengthening exercises, guided by a physical therapist, and a gradual return to sport.

If a fracture is not healing with non-operative management, then we may need to consider surgery. As the pars is a very small area of bone a direct surgical repair can be difficult. In some patients a spinal fusion may need to be considered.

SPINAL CONDITIONS

Spondylolisthesis

A spondylolisthesis is when one vertebral body slips forwards relative to the vertebral body beneath it. This will produce both a gradual deformity of the lower spine but also a narrowing of the spinal canal and the exit foramen. The exit foramen is where the nerves exit the spine. A spondylolisthesis can cause pain in the back, pain in the legs, or both.

Spondylolistheses are classified by their cause. The commonest types are lytic and degenerative spondylolisthesis:

Lytic spondylolisthesis: This is a spondylolisthesis that occurs in a vertebra previously affected with a pars fracture or spondylolysis. This typically occurs at the L5/S1 level. This tends to cause nerve pain in the leg (sciatica).

Degenerative spondylolisthesis: A degenerative spondylolisthesis occurs as a result of the degeneration of the lumbar facet joints. The degenerative changes lead to an alteration in the shape of these joints, meaning that there is less bony resistance to abnormal movement. A degenerative spondylolisthesis is most often seen in older patients, and typically occurs at the L4/5 level. This tends to present with symptoms of stenosis.

A spondylolisthesis can also occur due to a congenital abnormality of the posterior spine (dysplastic), following trauma (post-traumatic), due to a weakness secondary to a bone disease or tumour (pathologic), or following previous lower back surgery (Iatrogenic).

The severity of a spondylolisthesis is classified according to the percentage of slip relative to the vertebral body below. A slip of 0-25% is classified as Grade 1, a slip of 25-50% is classified as Grade 2, a slip of 50-75% is classified as Grade 3, and a slip of 75-100% is classified as Grade 4.  If the vertebral body slips completely off the front of the vertebra below then this is termed a ‘spondyloptosis’, or Grade 5 spondylolisthesis. The degree of vertebral slippage does not directly correlate with the amount of pain a patient will experience.

Diagnosis

A spondylolisthesis can be diagnosed by a MRI scan or X-ray. Occasionally a patient will also require a CT scan to give a clear picture of the bony anatomy.

Man with leg pain walking down the stairs

Treatment of pars fractures

The initial management of a pars fracture is a period of rest and complete abstinence from all sport and physical exertion for at least 2-months. For some patients this may also entail having to wear a brace. This period of rest is followed by trunk and abdominal strengthening exercises, guided by a physical therapist, and a gradual return to sport.

If a fracture is not healing with non-operative management, then we may need to consider surgery. As the pars is a very small area of bone a direct surgical repair can be difficult. In some patients a spinal fusion may need to be considered.

Testimonials

I wanted to take the opportunity to thank you and your team following my surgery. It has been so long since I felt so well and without pain. The surgery and my recuperation has far surpassed my expectations and has made a huge difference to my lifestyle.

Get in Touch

Our tailored approach can help you regain comfort, mobility, and a pain-free lifestyle.

Contact us today to take the first step towards recovery.