Isthmic Spondylolisthesis: Causes, Symptoms, and Treatment Options
The spine is (literally) the backbone of all human movement. Despite its major role in our daily activities, it’s also quite delicate and vulnerable to various conditions, including isthmic spondylolisthesis.
Occurring in an estimated 4 to 8% of the population, isthmic spondylolisthesis is a particularly common type of this spinal disease. Here, we’ll explore its causes, symptoms, and treatment options, including conservative and surgical therapies to consider.
What is Isthmic Spondylolisthesis?
Isthmic spondylolisthesis is a spinal condition that occurs when a vertebra slips down over the next vertebra in the spine. It results from a fracture or defect in the pars interarticularis (the bone that links the adjacent facet joints), also known as spondylolysis.
The pars interarticularis is a small piece of bone located between the upper and lower facet joints. It acts like a bridge between the joints and provides essential structural stability for the vertebrae. When a crack develops in the pars, it significantly diminishes the spine’s stability, creating the risk of vertebral slippage.
Isthmic Spondylolisthesis Causes and Risk Factors
Isthmic spondylolisthesis is caused by a defect, or fracture, in the pars interarticularis. Possible causes and risk factors for this defect include stress fractures, genetic factors, spinal anatomy, and older age.
- A stress fracture of the pars interarticularis is a small break in the bone. It results from repeated stress over time, creating small cracks that eventually become a full break. Overuse is the primary cause of this type of stress fracture, and it’s particularly common in children and adolescents who participate in contact sports, gymnastics, and other activities that place notable stress on the spine.
- Genetic factors can elevate your risk of isthmic spondylolisthesis. Some people are genetically predisposed to develop a pars interarticularis fracture, and a family history of spondylolisthesis is a notable risk factor.
- Spinal anatomy can play a role in isthmic spondylolisthesis because some people are born with a thinner pars interarticularis than others. When this piece of bone is naturally thin, it’s more likely to develop a stress fracture.
- Older age puts you at a higher risk of developing various spinal conditions, including isthmic spondylolisthesis. Bone density declines with age and older adults are more prone to falls – both of these factors contribute to a higher risk of spondylolysis.
Common Symptoms of Isthmic Spondylolisthesis
Common symptoms of isthmic spondylolisthesis include lower back pain, numbness, tingling, weakness, back stiffness, and muscle tension and spasms.
- Lower back pain from isthmic spondylolisthesis may feel like a deep, dull ache or a sharp, piercing pain. Many people with this condition experience pain that radiates down into the buttocks and legs. Additionally, the pain tends to get worse with certain movements, like standing and walking, and improves when you lie down.
- Numbness, tingling, and weakness can occur if the vertebra that slips out of place compresses a spinal nerve. The compressed nerve sends abnormal signals to the areas it supplies sensation to, like the leg muscles, leading to various symptoms.
- Back stiffness often occurs with isthmic spondylolisthesis due to spinal instability and nerve impingement. You may find it difficult to move your back or do activities that require back mobility, like bending down to tie shoelaces or retrieving items from high shelves.
- Muscle tension and spasms, especially in the leg muscles, can accompany spondylolisthesis. This occurs when the misaligned vertebra presses on spinal nerve roots, causing them to send abnormal signals to their corresponding muscles. The muscles may then contract and spasm involuntarily.
Isthmic vs. Degenerative Spondylolisthesis
Isthmic spondylolisthesis results from a pars interarticularis defect, while degenerative spondylolisthesis results from spinal wear and tear.
Here are other key differences between these types of spondylolisthesis:
- Isthmic spondylolisthesis is more common in kids and teens – particularly teen athletes. Degenerative spondylolisthesis is more common in older adults.
- Isthmic spondylolisthesis is often related to repeated stress on the spine from physical activity, while degenerative spondylolisthesis stems from age-related spinal changes.
- Degenerative spondylolisthesis often occurs with other degenerative conditions, like osteoarthritis and spinal stenosis.
How Do You Treat Grade 2 Isthmic Spondylolisthesis?
Lifestyle Adjustments
Various lifestyle adjustments can help alleviate pressure on the spine and prevent nerve irritation from isthmic spondylolisthesis, including:
- Avoiding activities and movements that increase pressure on the spine (particularly deep spinal twisting and bending)
- Staying active with gentle, low-impact exercise
- Quitting smoking, which can compromise blood flow to the spine and stunt the body’s natural healing process
- Eating a nutritious diet to avoid nutrient deficiencies that could derail healing efforts
Back Bracing
Back bracing can help stabilize the spine as it heals from grade 2 isthmic spondylolisthesis. Bracing can also help you move more comfortably and lower your pain levels. Studies show that wearing a brace can relieve symptoms of lumbar spondylolysis, the precursor to lumbar isthmic spondylolisthesis.
Over-the-Counter Pain Medications
Over-the-counter pain medications, like NSAIDs, are often used for symptom management in people with grade 2 isthmic spondylolisthesis. While it won’t cure the cause of your symptoms, it can help you feel more comfortable while your body heals.
Physical Therapy Approaches
Physical therapy approaches for isthmic spondylolisthesis typically center around strengthening the core, releasing the hamstring muscles, correcting movement mechanics, and adjusting daily activities to facilitate healing.
- Core strengthening spondylolisthesis exercises, like pelvic tilts and curl-ups, help stabilize the spine to prevent further injury. A strong core also helps limit impact on the spinal structures, which can ward off worsening nerve impingement.
- Releasing tight muscles (usually the hamstrings and glutes) can help calm the spasms that often come with spondylolisthesis. Your PT can recommend targeted stretches and may suggest complementary treatments, like massage therapy and acupuncture, to further release muscle tension.
- Correcting problematic movement mechanics, like an imbalanced gait, may be included in your PT treatment plan. Amending these abnormalities can help distribute impact evenly across the body and reduce impact on the vertebrae affected by spondylolisthesis.
- Lifestyle adjustments, like modifying or avoiding certain activities and implementing low-impact exercise, can complement the results of other PT methods for spondylolisthesis.
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Indications for Surgery
Indications for surgery with isthmic spondylolisthesis include severe symptoms, progressive neurological symptoms, immobility, and failed conservative treatments.
- Severe symptoms
Severe back pain, muscle spasms, and stiffness can seriously compromise your quality of life. When isthmic spondylolisthesis symptoms reach this degree of severity, conservative treatments may not offer a noticeable improvement, making surgery a necessity.
- Progressive neurological symptoms
Neurological spondylolisthesis symptoms like tingling, numbness, and weakness can often be addressed with conservative treatments. However, if they progressively get worse or advance to problems like bladder or bowel incontinence, it’s time to consider surgery.
- Immobility
When isthmic spondylolisthesis severely compromises your ability to move and becomes a disability, surgery may be required to restore a healthy range of motion.
- Failed conservative treatments
Have you followed your doctor’s conservative spondylolisthesis treatment plan for months (or even years) to no avail? Doctors may consider surgery for isthmic spondylolisthesis cases that don’t respond to consistent non-surgical therapies.
Surgery for Isthmic Spondylolisthesis
Surgery for isthmic spondylolisthesis may involve pars defect repair, spinal decompression, and a form of stabilization (conventionally spinal fusion).
- Pars defect repair is a procedure that directly repairs the damaged pars interarticularis using hardware. This process stabilizes the spine and keeps the fracture from worsening. It’s typically done in teens who don’t have tissue damage surrounding the fracture.
- Spinal decompression surgery involves relieving pressure on spinal nerves that are impinged by the slipped vertebra. Laminectomy is the most common technique, and it involves removing part of the bone that covers the back of the spinal canal, creating more room for the nerves.
- Spinal fusion is the conventional choice to stabilize the spine with isthmic spondylolisthesis. It involves fusing the affected vertebrae into a single bone. To avoid compromising spinal mobility, modern alternatives like the TOPS System are now being used to create a controlled range of motion without limiting the patient’s movements.
Post-Treatment Protocols
Post-treatment protocols for isthmic spondylolisthesis include ongoing physical therapy, lifestyle adjustments, and a low-impact exercise routine. These protocols help build spinal stability over time while preventing excessive impact on the spine.
