Out-of-state? Free MRI review + telehealth consult before you travel4.9 ★ · 619 Google reviewsBoard-certified — American Board of Orthopaedic SurgeryMinimally invasive, same-day spine surgery in Beverly HillsCall (424) 217-7463
Out-of-state? Free MRI review + telehealth consult before you travel4.9 ★ · 619 Google reviewsBoard-certified — American Board of Orthopaedic SurgeryMinimally invasive, same-day spine surgery in Beverly HillsCall (424) 217-7463
When I evaluate someone with a pars defect, my first questions are straightforward: Is the fracture actually causing the pain? Is the spinal segment stable? Are the surrounding discs and joints reasonably healthy? And can we address the problem without sacrificing motion?
My goal is to understand the entire picture before recommending treatment. For some patients, that means nonsurgical care. For others with persistent symptoms, it may mean considering direct repair of the pars rather than fusion.
What is a pars fracture?
The pars interarticularis is a small bridge of bone between the upper and lower joint-bearing portions of a vertebra. A fracture or defect in this area is called spondylolysis. You may also hear it described as a pars defect, pars stress fracture, or lumbar spondylolysis.
It most commonly involves the L5 vertebra in the lower back, although other levels can be affected. The defect may occur on one side or both sides of the vertebra. Repeated loading can contribute to a stress injury, but a pars defect is not limited to competitive athletes or teenagers.[1]
No. These conditions are related, but they are not interchangeable.
Spondylolysis describes the pars defect. Spondylolisthesis describes one vertebra slipping relative to another. A pars defect can contribute to slippage, but finding a pars fracture does not establish that significant slippage or instability is present.[2]
This distinction matters when discussing treatment. I want to know whether we are dealing primarily with a painful fracture or with a broader problem involving the disc, joints, alignment, or stability of the spinal segment.
What symptoms can a pars fracture cause?
A symptomatic pars fracture often causes lower-back pain that becomes more noticeable with activity, particularly movements that extend the back. Some people experience pain during exercise or repetitive loading; others notice symptoms during ordinary daily activities.
However, some pars defects cause no symptoms at all. A finding on an imaging report does not necessarily identify the source of a person’s pain.[3]
That is why I do not recommend treating an image in isolation. I compare the imaging with the history, examination, and pattern of symptoms.
How I evaluate a pars defect
I begin by understanding when the pain started, which activities provoke it, what treatments have been tried, and how symptoms affect function.
Imaging helps answer different questions. X-rays assess alignment and slippage. CT provides detailed information about the bony defect. MRI evaluates the discs, nerves, and other tissues and can help identify an active stress injury. In selected cases, a targeted diagnostic injection may help determine whether the pars is contributing to the pain. Not every patient needs every test.[4]
When instability is a concern, appropriately obtained flexion-and-extension radiographs can contribute to the assessment. The findings must be interpreted alongside the rest of the evaluation—not as a single test that determines the operation.[5]
My assessment also considers whether there are other important pain sources. Repairing a pars fracture will not necessarily solve pain arising primarily from a severely degenerated disc or arthritic facet joints.
Can a pars fracture be treated without surgery?
Yes. Many patients improve with nonsurgical treatment. Depending on the stage of the injury and the patient’s symptoms, treatment may include modifying aggravating activities, a guided rehabilitation program, appropriate pain management, and—in selected circumstances—bracing.[3]
An early stress injury and a longstanding unhealed defect are not the same problem. Their potential for bony healing differs. Even when an established defect remains visible on imaging, the decision to operate should depend on symptoms, function, and the overall clinical assessment—not simply the continued presence of a fracture line.[1]
My preference is to use the least invasive effective treatment. Sometimes, if the pars defect is acute and very recent, it can potentially heal fully with aggressive nonoperative management, including activity modification, rigid bracing, and noninvasive focused shockwave therapy, which I offer in my office. I use a very high-quality, top-brand Chattanooga focused shockwave device. Treatment is typically about four sessions, one week apart, and each session usually lasts about seven minutes. Surgery is a consideration when symptoms remain meaningfully limiting despite appropriate care and the evaluation identifies a problem that surgery can reasonably address.
Direct pars repair is not limited exclusively to adolescents. It has been studied in selected adults, particularly when the surrounding discs and facet joints have little degeneration and the pars defect is believed to be the source of symptoms. The evidence is more limited in older adults, making careful selection especially important.[6]
In my practice, I evaluate adults for motion-preserving repair rather than dismissing the possibility based on age alone. However, being an adult with a pars fracture does not automatically make someone a candidate.
The key question is whether repairing the fracture addresses the actual problem while leaving a reasonably healthy, stable spinal segment intact. Now, with the newer technology of robotic guidance and lag-screw fixation, as well as the newer adjunct of focused shockwave therapy, the chance of successful pars repair in adults has increased dramatically compared with before.
What if a pars fracture is slow to heal?
Delayed union means healing is taking longer than expected; nonunion means the fracture has not united. When healing stalls, I reassess the fracture, stability, bone health, and the overall treatment plan rather than assuming that the same approach fits every patient.[8]
In my clinical practice, I have seen focused shockwave therapy help bone healing in many patients, including delayed unions and some nonunions, and I have observed faster progression toward union after adding it in selected cases. These are firsthand clinical observations, not a guarantee of healing. Its use around the spine requires an individual safety review, making sure the patient signs the appropriate consent form and has no contraindications, such as any type of cancer, infection at the site, or a history of a pacemaker, among others. The accompanying robotic pars repair page explains my approach in more detail.
When might fusion still be appropriate?
Direct repair is not the right operation for every pars defect. Significant instability, substantial or progressive slippage, advanced disc degeneration, or other structural problems may make fusion or another treatment more appropriate.[6]
My philosophy is not to avoid fusion at any cost. It is to avoid unnecessary fusion when a more targeted treatment is appropriate.
Patient story: a college athlete’s pars repair
One of the patient stories on my website describes a college softball player whose persistent back pain was linked to a pars defect. I repaired the pars fracture and addressed a bone spur with microdecompression after other surgeons had recommended fusion.
American Academy of Orthopaedic Surgeons (OrthoInfo), “Nonunions”
Questions, Answered
Frequently asked questions
What is the difference between a pars fracture and spondylolysis?
Spondylolysis is the medical term for a fracture or defect in the pars interarticularis, a small bony bridge in a vertebra. A pars defect, pars stress fracture, and lumbar spondylolysis describe closely related findings; imaging helps distinguish an early stress injury from a longstanding defect.[1]
How is spondylolysis different from spondylolisthesis?
Spondylolysis describes the pars defect. Spondylolisthesis describes one vertebra slipping relative to another. A pars defect can contribute to slippage, but the two findings are not interchangeable. I assess the amount of any slip and whether the segment is stable before discussing treatment.[2][6]
Does a pars defect always cause back pain?
No. Some pars defects are incidental findings and cause no symptoms. I compare the history, examination, and imaging to determine whether the pars is the likely pain source or whether another condition better explains the symptoms.[3]
Can a pars fracture improve without surgery?
Yes. Many patients improve with activity modification and guided rehabilitation; selected patients may also benefit from bracing or other nonsurgical care, especially focused shockwave therapy. An early stress injury and a chronic unhealed defect have different healing potential. Improvement in symptoms does not necessarily mean the fracture has united.[1][3]
Does a pars fracture automatically require fusion?
No. Some patients do not need surgery, and selected patients with persistent symptoms may be candidates for direct pars repair. Fusion may still be appropriate when significant instability, degeneration, or other structural problems make repair unsuitable.[6]
What determines whether an adult is suitable for pars repair?
I consider whether the pars is the likely pain source, disc and facet-joint health, spinal stability, bone quality, and the response to nonsurgical treatment. Age alone does not determine candidacy. Minimal, stable slippage may be compatible with repair in selected cases, but every patient requires an individual assessment.[6]
Seeking a second opinion for a pars fracture
Being told that you have spondylolysis—or that fusion has been recommended—does not mean you should make a decision without understanding the alternatives.
At The Spine Pro, I evaluate patients seeking an explanation of their diagnosis, an assessment of prior imaging, and an individualized discussion of nonsurgical treatment, direct pars repair, and fusion when necessary.
Request a pars fracture consultation or second opinion at our Beverly Hills office, serving patients throughout Los Angeles and beyond. We offer telehealth appointments as well.
New bladder or bowel dysfunction, saddle numbness, or rapidly worsening leg weakness requires urgent medical assessment rather than waiting for a routine consultation.[7]
