What is Lumbosacral Spondylolisthesis?
Lumbosacral spondylolisthesis is a condition where the fifth bone in the lower spine (L5) slides forward over the first bone in the sacrum region (S1). This happens mainly due to a defect in the L5 bone (spondylolysis) or repeated strain or injury. The more the bone slips, the more symptoms one may experience.
About 6% of people generally have spondylolysis, and one-third of these people may develop some degree of spondylolisthesis. But don’t worry, in most cases, the condition is mild or doesn’t cause symptoms and only a small number of people with symptoms really need surgery.
This condition is most common in children and teenagers who take part in sports requiring repetitive bending backwards of the lower back. Sports like diving, cricket, baseball, softball, rugby, weightlifting, sailing, table tennis, wrestling, gymnastics, dancing, and football are examples where this could occur. These individuals usually experience lower back pain that worsens with activity. Sometimes, the pain can spread to both buttocks and legs, and in severe cases, it can affect how a person walks. In adults, symptoms can be more subtle and are often related to long-term degenerative changes due to the slip, which can lead to a narrowing of the space in the spinal canal (spinal canal stenosis) and radiating pain.
As for treatment, most cases can be managed non-surgically. However, if the non-surgical treatment isn’t effective and the symptoms continue to disable the person, surgery may be required.
What Causes Lumbosacral Spondylolisthesis?
The Wiltse-Newman classification system breaks down the different reasons why the pars interarticularis, a small segment of the vertebrae in your spine, might fail or break. It identifies five types:
* Type I: Dysplastic – a defect in the pars you’re born with
* Type II (isthmic) is the most common
* II-A: a break in the pars due to repeated stress
* II-B: lengthening of the pars due to multiple healed stress fractures
* II-C: a fresh break in the pars
* Type III: Degenerative spondylolisthesis – movement of a vertebra due to instability from aging, not related to a break in the pars
* Type IV: Traumatic – due to a fresh break in the arch of the vertebra, which isn’t in the pars
* Type V: Neoplastic – destruction of the pars due to a tumor
The seriousness of this process is measured according to how much a vertebra slips forward. It can range from mild to severe or a complete slip, known as spondyloptosis.
In the most common form of this condition, which is isthmic spondylolisthesis leading to an L5/S1 slip, the following stages have been defined:
* A reaction to stress in the pars (thickening with an incomplete break in the bone)
* Spondylolysis (a defect in the pars that shows up as a gap on X-rays and is surrounded by thickening of the bone, without any movement of the vertebra)
* Spondylolisthesis (a vertebra slipping forward over the one beneath it due to both sides of the pars having a defect)
The next common types of spondylolisthesis are type I (dysplastic) and type III (degenerative). The degenerative type is seen most often in adults, with the L4/L5 and L3/L4 levels being the most frequently affected. Because the instability lasts for a long time, the space between the vertebrae and the facet joints often undergo related degenerative changes. These often lead to secondary thickening of the ligamentum flavum, a ligament in your back, and subsequent narrowing of the spinal canal. This condition usually causes pain in both buttocks and a condition known as neurogenic claudication, which is back pain that eases when you sit down or lean forward.
Risk Factors and Frequency for Lumbosacral Spondylolisthesis
Lumbosacral spondylolisthesis, a condition affecting the lower part of the spine, is thought to be present to some degree in 4 to 6% of the population. However, in most cases, it doesn’t cause any symptoms. The condition is most common and tends to be more severe in children and teenagers who participate in sports that involve a lot of back extension. Adults, on the other hand, usually experience milder symptoms that develop slowly over time.
Adolescents who are particularly at risk include female dancers and gymnasts who have excessive inward curvature of the spine (hyperlordosis) and high flexibility, teenage boys who are football players or weightlifters with limited back movement going through a growth spurt, and young athletes who are training hard but have weak core muscles. Certain inherited factors and birth defects could also increase the risk, including a mild form of spina bifida, excessive outward curvature of the spine in the chest area (thoracic hyperkyphosis, also known as Scheuermann’s disease), and unusually loose ligaments.
It’s also worth noting that several anatomical factors can make a person more likely to develop spondylolisthesis.
Signs and Symptoms of Lumbosacral Spondylolisthesis
Spondylolisthesis is a spine condition that often doesn’t show symptoms. In rare cases, when the problem is severe, people might experience discomfort or changes in the way they move.
If you’re a young child between 4-6 years old and involved in activities that strain the back, like gymnastics, football, or weight lifting, you could begin to feel discomfort. Adults might start to notice a gradually worsening back pain that gets worse during physical activity or comes and goes with varying degrees of intensity. There might be pain, weakness, or “pins and needles” in the foot, bladder or bowel problems, or discomfort in the buttocks and legs when walking that gets better when you lean forward or sit down.
On physical examination, officials might notice:
- Pain when arching the back sharply
- Difficulty bending the lower back
- Tightness in the back of the knee
- Changes in the way you walk
- Flattening or forward curve of the lower spine
- A noticeable bump in the spine
- Tightness in the hamstrings
- Buttocks appearing heart-shaped in severe cases
- Pain in the lower back or legs when lifting the legs straight up
- The presence of a sideways curve of the spine (scoliosis).
Sometimes, the symptoms can get significantly worse quickly, especially during periods of rapid growth or increased physical activity. This could lead to serious back pain made worse by arching the back and eased by resting, nerve problems, or walking with a stooped gait due to hamstring tightness.
Testing for Lumbosacral Spondylolisthesis
After your doctor asks about your medical history and examines you, they may use a specific type of X-ray known as an AP and lateral weight-bearing X-ray of the lower back. This X-ray can help evaluate conditions like lumbosacral spondylolisthesis, where one of your lower vertebrae slips forward onto the bone directly beneath it. This is best seen on a side view, but your doctor will also look for any deformities on a front view.
If your doctor suspects that the balance of your spine is off, they might order a full spine X-ray while you’re standing. Sometimes, a condition called an isthmic defect can be seen on a regular X-ray. But if your doctor can’t tell for sure, they might use an MRI scan, which uses magnetic fields to create detailed images of your spine.
There are other scans like oblique X-rays of the lumbosacral junction, CT scans, or SPECT scans that can help identify issues, but they involve exposure to ionizing radiation, which can have side effects.
MRI scans are particularly useful because they can detect stress reactions even before a fracture occurs. Certain abnormalities like an unusual shape of the vertebra or facet joints (parts of your spinal bones) also show up well on MRI scans. Rare conditions like tumors or infections should be considered if you have additional symptoms like fever and weight loss.
Your doctor might also use flexion and extension views, which are X-rays taken while you bend forwards and backwards. This helps them assess if there are any abnormal movements in your spine. Spondylolisthesis is diagnosed if there is either 4 mm or more of movement or over 10 degrees of motion compared to the nearby parts of your spine.
Spondylolisthesis is graded based on how much of the vertebra slips forward, which is seen on a side X-ray:
* Grade I is less than 25% slip
* Grade II is 25% to 50% slip
* Grade III is 50% to 75% slip
* Grade IV is 75% to 100% slip
* Grade V is more than 100% slip (called spondyloptosis)
A measurement called pelvic incidence (PI) has a direct relationship with the grade of spondylolisthesis.
Doctors follow a new system that guides how to treat spondylolisthesis based on the slip percentage, PI, and your overall spinal alignment. This leads to different strategies for each:
* Types I & II: Less than 50% slip. Surgery is only suggested if symptoms can’t be controlled in other ways.
* Type III: Less than 50% slip, but a high PI. Back fusion may be considered.
* Type IV: More than 50% slip, but a balanced pelvis. Decompression and possible back fusion may be enough.
* Type V & VI: More than 50% slip and an unbalanced back or spine. The doctor may consider reducing the slip and fusing the spine.
Finally, MRI (specifically the T-2 weighted sequence) is ideal to check for conditions like spinal canal stenosis (narrowing), nerve root impingement (pressure on nerve roots), and foraminal stenosis (narrowing of the openings where nerve roots exit the spine). Your doctor often targets the L5 nerve root, which is typically most affected. This information helps your doctor design the best surgical plan if needed.
Treatment Options for Lumbosacral Spondylolisthesis
Most individuals with back pain problems can often be treated without surgery by doing the following:
- Wearing a thoracolumbosacral or lumbosacral brace. This can be particularly helpful in adolescents who play sports, as the brace prevents overstretching of the spine.
- Modifying their activities to avoid overextending the spine.
- Strengthening core muscles, particularly the deep abdominal muscles and the multifidus muscle in the back.
- Doing exercises that focus on bending the lower back.
- Taking pain-relieving medication.
- If the cause of the back issue is the degeneration of the spine in adults (known as spondylolisthesis) that results in narrowing space in the spine (canal stenosis), an injection of steroids into the spine can provide short-term relief.
Non-surgical treatments have been highly successful in sportspersons experiencing a sudden onset of back pain, with 95% not requiring surgery. In fact, most of them were able to return to their previous sports activities. However, around one-third of patients with spondylolisthesis experience worsening symptoms over time, and surgery is eventually needed for those with severe pain or nerve symptoms.
Surgical interventions, when appropriately chosen for the patient, show over 80% success rates with few complications.
In children or adolescents with fractures in the bone connecting the upper and lower sections of the spine (pars fracture), surgical repair may be considered. There are a number of methods available, such as using screws or wire techniques to stabilize the bone.
Other surgical techniques involve the removal and fusion of the affected part of the spine. This could be a simple fusion, or in some cases there’s a need to relieve pressure on the nerves (decompression) in addition to fusion. However, it’s important to know that these surgeries primarily aim to relieve symptoms, and not necessarily restore the slipped vertebra to its original place.
If all non-surgical options have failed or symptoms are severe, more complex surgical options may be considered. These may involve inserting devices between the vertebrae or removing a vertebra entirely for better alignment of the spine. In making these decisions, doctors consider factors such as the extent of the slip, the presence of nerve issues, and the patient’s overall health condition. Recently, minimally invasive surgical techniques have gained popularity.
What else can Lumbosacral Spondylolisthesis be?
There can be several reasons for someone experiencing back pain. Some of these causes include:
- Mechanical or muscular issues
- Wear and tear of the discs or joints in the back (disc degeneration or facet joint osteoarthritis)
- Narrowing of the spinal canal due to age-related changes (lumbar canal stenosis)
- A growth or spread of cancer in the back (neoplastic process/metastases)
- Infections such as discitis or tuberculosis, or an abscess close to the spinal cord
- Pain related to issues with blood circulation, which gets better when at rest in a standing position (vascular claudication). On the other hand, pain that gets better when bending forward or sitting is known as neurological claudication, and it’s usually caused by spine damage.
What to expect with Lumbosacral Spondylolisthesis
Even though it’s estimated that up to 6% of people have a spine condition called spondylolisthesis, most of them show no symptoms and are therefore unaware of their condition. Only a tiny portion of those who do have symptoms from spondylolisthesis will need to consider surgery.
The following conditions could lead to a worse outcome:
* A very young age when the disease first starts
* Being a female
* The angle of the spine misalignment is more than 45 degrees
* A severe level of spine slippage
* Having a type of spondylolisthesis that develops with age (this is more common in adults).
Possible Complications When Diagnosed with Lumbosacral Spondylolisthesis
After surgery for a condition called lumbosacral spondylolisthesis, the most common nerve-related problem that patients report is a dysfunction in a nerve called L5. This issue tends to occur most often with severe slips or attempts at reducing the slip, as well as the procedure to relieve pressure in a narrowed spinal canal. Thankfully, this nerve problem typically goes away on its own within a few months after the surgery. A study using cadavers discovered that the majority (71%) of the nerve strain happens during the second half of this reduction process.
There are also other possible complications from this type of surgery:
- Pseudoarthrosis: This is a type of non-healing after a broken bone has been surgically fixed.
- Dural tear: This is a tear in the outermost membrane that surrounds the spinal cord.
- Adjacent Segment Disease: This happens to about 2 to 3% of patients and involves problems in the vertebrae next to the ones that were operated on.
- Surgical Site Infection: This affects 0.1 to 2% of patients and is an infection in the area where the surgery was done.
- Positioning neuropathy: This involves potential nerve problems due to the position the patient is placed in during surgery. Specifically, issues can be with the lateral femoral cutaneous nerve (from its prone position with an iliac bolster), the ulnar nerve, or a condition affecting the shoulder, arm and hand nerves called brachial plexopathy where the arm position has been incorrect.
Please note that the chance of having problems after the surgery increases with the patient’s age, amount of blood loss during the surgery, length of the surgery, and number of vertebrae that were fused together.
Preventing Lumbosacral Spondylolisthesis
Sports coaches and personal trainers who work with children and teenagers, particularly those involved in gymnastics, football, or weight lifting, should be vigilant about recognizing signs of two back conditions called spondylosis and spondylolisthesis. These conditions can cause back pain that doesn’t improve with rest or basic stretching and strengthening exercises. Coaches and trainers should be able to spot these signs in young athletes and refer them to a specialist for a precise diagnosis and treatment.
Braces that restrict certain movements and reducing the intensity of an athlete’s activities can significantly alleviate these conditions. Therefore, it’s considerably important for athletes to be aware of these solutions.
People diagnosed with these conditions should learn about the significance of altering their activities and physiotherapy. Engaging in exercises that strengthen the body’s core muscles and increase flexibility can help manage symptoms.
They should be comforted to know that most symptoms of these conditions are temporary. However, athletes at a high risk of their vertebrae slipping further (a condition known as slip progression) should regularly visit an Orthopedic specialist. These specialists can provide more information about signs of worsening conditions and potential serious complications like cauda equina syndrome, which is a severe neurological condition caused by compression of spinal nerve roots.