Spondylolysis is a stress fracture of the pars interarticularis bone found on the posterior aspect of the spine. The pars interarticularis is the weakest part of the spine, especially in younger patients whose bones are still maturing. As seen in the image below, the red line marks the fracture line through this portion of the bone. When this fracture occurs, the vertebral body can slip forward otherwise known as an Isthmic Spondylolisthesis. This can be caused by traumatic impact from repetitive hyperextension of the spine from a sport like gymnastics, car accidents, a fall, or degenerative/genetic changes to the bone to name a few. Treatment is often aimed toward symptom management and surgical intervention will only be recommended if this causes severe nerve compression, intractable pain, or progressive neurologic damage.
In order to understand the cause of Spondylolysis, it is important to understand the anatomy of the spine. The spine consists of bone, discs, soft tissues, and nerves. There are 7 cervical, 12 thoracic, and 5 lumbar vertebral bodies stacked on top of one another. The disc lives between each bone and acts as a shock absorber of the spine. Behind the vertebral bodies and discs are the bones of the spinal column which bridge to form the spinal canal, which holds the spinal cord and adjacent nerves. The pars interarticularis is an important part of this structure. As this is a weak area of bone, especially in patients not yet skeletally mature, when extreme forces are applied a stress fracture can form. Repetitive hyper-extension or rotational forces, such as with gymnastics or baseball, are common mechanisms to develop a Spondylolysis. It is common in the younger population, estimated that 5-7% of adolescents have pars stress fractures. Fortunately, with proper rest and abdominal core strengthening this fracture normally heals within 6-8 weeks. Other causes of spondylolysis include genetics, spinal tumors, trauma, and in some cases the cause is unknown which is referred to as idiopathic.
The most common presenting symptom of a stress fracture in the pars interarticularis is back pain, muscle spasms, or stiffness in the low back. Your symptoms can range from mild to severe depending on the severity of the fracture or instability in the spine. In some cases, you may have symptoms of radiculopathy. These include pain, numbness, weakness, or tingling in the legs. If the fracture is severe enough causing a slippage, referred to as isthmic spondylolisthesis, there may be varying degrees of central stenosis which can be severally pinching the nerves potentially resulting in symptoms of cauda equina syndrome. If you experience loss of bowel or bladder control, urinary urgency, numbness or weakness in the legs, or numbness in the groin, contact your spinal expert immediately.
Diagnosis of Spondylolysis involves obtaining a detailed medical history, performing a comprehensive physical exam, and imaging studies including weight bearing x-rays, MRIs, or CT-scans.
Treatment is often aimed first at managing your symptoms non-surgically. This includes spine-specialized physical therapy, manual massage, anti-inflammatory medications, dry needling, and low impact exercise and proper nutrition. You also may require medical management by your primary care provider to optimize your bone density. Diagnostic injections may be performed using a numbing medicine, in order to verify the source of your pain is coming from the suspected stress fracture site. In certain situations your spinal specialist may even discuss regenerative medicine treatment options to treat symptoms related to your Spondylolysis. The goal of surgery is to stabilize the spinal segment, most commonly through a spinal fusion procedure. This decreases the amount of motion of one vertebral segment on top of another to reduce pain, relieve pressure off of nerves, increased stability, and correct misalignment. Each surgical plan is determined after a thorough evaluation with your spinal specialist at the Virginia Spine Institute and specific to each patient. See below for some common treatments for spondylolysis.
Spine-Specialized Physical Therapy →
Here is a list of surgical options to treat spondylolysis:
Anterior Lumbar Interbody Fusion (ALIF) →
Lateral Interbody Fusion (XLIF, DLIF) →
There are many surgical treatment options click here to learn more
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Reviewed by: Dr. Christopher Good, MD, FACS.