Stress Fracture of the Spine (Spondylolysis)
Overview of Spondylolysis: Index of Suspicion
A stress fracture of the spine, spondylolysis, can be a difficult diagnosis, and therefore needs careful examination and imaging evaluation. As in most things in medicine, there are patterns to watch for when suspecting a stress fracture of the lumbar spine. The first piece of important information is the type of athlete you are dealing with and the volume of activity they are performing. High-risk athletes that do a significant amount of back extension (leaning back), would include gymnasts, dancers, soccer athletes and football lineman. In particular, high-level gymnasts can train 20 or more hours per week. Typically athletes will complain of generalized back pain particularly with back extension activities. Younger healthy patients generally do not complain of any neurologic symptoms such as numbness, tingling or weakness in the legs.
A Logical Approach
If I suspect a stress fracture I take a very deliberate and logical approach. I would obtain an x-ray of the lumbar spine to see if there are any obvious abnormalities causing pain. In general, when the pain is gradual in nature, without trauma, the x-ray is typically normal. There is some debate on the type of views to obtain in a lumbar series, but I would simply order a front and side view (AP and Lateral). It is appropriate to also obtain oblique x-rays as well however due to the low amount of positive findings I try to limit the x-rays to the pelvic region. For simplicity sake ,I will use only the lateral views to illustrate the injury as the anatomy is much easier to understand.
Normal Spine Model (Side View)
Stress fractures occur in an area of the vertebra called the pars interarticularis
Normal X-Ray Lumbar Spine (Side View)
X-ray showing appropriate alignment of the vertebrae as well normal disc spacing and no fracture seen in the pars interarticularis
Spondylolysis X-Ray Lumbar Spine (Side View)
X-ray showing fracture seen in the pars interarticularis
To MRI or Not to MRI
If I have a negative x-ray and high suspicion of a stress fracture I will give the patient and family a few options. If there are financial reasons or personal preference not to get an MRI, I will treat presumptively and recommend rest and physical therapy. If the athlete wishes to continue with sports I will proceed with an MRI. I prefer MRI, if there is no clear fracture, as it is more sensitive at picking up more subtle inflammation in the bone (stress reaction). Additionally an MRI can pick up any incidental findings in the soft tissue such as muscle, nerve or disc. Lastly, an MRI does not have the exposure of radiation that one would get with a CT scan. A CT scan may be helpful once an area of concern is identified to better characterize if a clear fracture is present.
MRI Lumbar Spine (Side View)
MRI showing inflammation of the pars interarticualris portion of the vertebra within the L5 vertebra.
CT Scan Lumbar Spine (Side View)
CT scan showing fracture of the L4 pars interarticualris portion of the vertebra
Spondylolysis Treatment Plan
Once a stress reaction or stress fracture is identified, typically rest is the mainstay of treatment. I usually will recommend the patient completely rest for 6 weeks to ensure that they are pain free. Once the patient is completely pain free, I will have them start physical therapy that works primarily on low back and core strength. One could definitely make the argument to start physical therapy sooner if the patient is pain free at rest. If so, I recommend only therapy exercises that do not cause the patient to extend their back. At 3 months, I will usually progress the patient back to full sports activity if they have been pain free with all physical therapy activities. Some sports medicine physicians will also use a brace during the healing process, but that is not uniformly accepted. In my experience I have had good outcomes with this treatment protocol without needing a brace.
A couple of things to note regarding a spondylolysis. If a patient has a spondylolysis that has previously healed they certainly are susceptible to aggrevation of the injury. It can be difficult to assess whether a stress fracture is new or old and that will factor into the decision regarding imaging. In addition to the fracture there can also be movement of the bone called spondylolisthesis, which will be discussed in another post.
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