MRI Findings Not Helpful In Determining Herniated Disc-Related Sciatica Treatment

Patients often come to the doctor for treatment of a back ailment, and two of the most common are sciatica and herniated discs. When leg pain, numbness or weakness occurs, most clinicians and patients will turn to the same diagnostic tool: an MRI scan. The assumption is simple: if imaging can demonstrate the problem, it should also be able to reveal the optimum treatment strategy. But the connection between the MRI and patient’s symptoms is much more complex.

Lumbar disc herniations are the result of the soft inner portion of the disc in the spine bulging outwards and possibly damaging the surrounding nerve roots. This irritation may lead to radiating pain, numbness or weakness down one or both legs (sciatica, or more specifically lumbar radiculopathy). Although this diagnosis is common, determining the need for surgery or conservative treatment is a major clinical dilemma.

Introduction

MRI is a common test ordered for patients with sciatica, as it gives detailed pictures of disc herniation, nerve root compression and the anatomy of the spinal canal. However, new studies show that MRI data is not enough and can sometimes be misleading when deciding on treatment. In particular, MRI scans are often abnormal even in individuals with no symptoms at all. This article reviews a major clinical study and the overall evidence base to assist patients and clinicians in understanding the limitations and value of MRI in the diagnosis of sciatica.

Sciatica is a condition characterized by pain that travels down the length of the sciatic nerve from the lower back through the hips and buttocks down each leg. It is not a diagnosis, but a group of symptoms resulting from inflammation or compression of one or more nerve roots in the lumbar spine.

Symptoms of sciatica are:

• The pain is sharp, stabbing or shooting from the lower back into the leg
• Numbness or tingling in the leg, foot or toes
• Weakness of the affected leg muscles
• Pain that increases with sitting or certain movements

Unlike lower back pain in general, the main complaint of people with sciatica is the pain in the leg, not the back. Symptoms may be mild and intermittent or severe and disabling and will differ widely from person to person depending on the extent of nerve irritation, sensitivity to pain, extent of inflammation and general health.

It is important to note that the same MR finding can cause very different symptoms in different patients, which has implications for treatment planning. The most common cause of sciatica is lumbar disc herniation, although spinal stenosis and degenerative disc disease are also known causes of sciatica. Some leg pain blamed on a disc is in fact piriformis syndrome, not true sciatica, which is why an accurate diagnosis matters.

This rapid triage guide will help you determine if your symptoms are urgent enough for immediate attention, require a specialist’s evaluation, or can be managed conservatively.

If you have any of the following, seek Emergency Care Immediately, go to an emergency room or call emergency services now:

• Sudden loss of bladder or bowel control
• Saddle numbness, numbness or tingling in the groin, inner thighs or genitals
• Sudden onset of leg weakness that’s worsening over hours
• Severe neurological symptoms that developed suddenly
• Back pain, fever, and drenching night sweats, or unexplained weight loss
• Back pain after a big fall, accident or trauma

These symptoms can be associated with cauda equina syndrome, infection of the spine, a fracture or malignancy. These are emergency situations that are time sensitive. Avoid waiting to see if symptoms improve.

Schedule a Specialist Evaluation Soon See a spine specialist within the next few days if you have:

• Weakness in the legs that gradually progresses over days or weeks
• If the sciatica pain does not go away after 6 weeks, it may be a sign of a more serious condition
• Leg pain that is so bad that it makes it hard to do everyday things
• Numbness or weakness in your foot or ankle that affects the nerves

Conservative Care Is Likely Appropriate Most patients with these symptoms improve without surgery:

• Recent onset of leg pain or paresthesias (tingling sensation) in the leg (less than 6 weeks)
• Symptoms that don’t change or are slowly getting better
• Worsens with certain positions, but improves with movement or rest
• No symptoms of bowel, bladder or progressive weakness

But MRI results should be treated with great suspicion. Asymptomatic disc herniations, bulges and degenerative changes are very common and have been shown in landmark research by Boden et al and later by systematic reviews to be common in adults over 40 years of age, even though there are no symptoms.

This poses a basic clinical dilemma: When a patient with symptoms comes in for an MRI, it is often difficult to tell from the MRI whether a particular finding is responsible for the patient’s pain or if it is an incidental finding. MRI findings alone are not a reliable predictor of pain, functional limitation or treatment outcome.

If a patient complains of pain due to a herniated disc or sciatica, the first test that is ordered is usually an MRI. Imaging is useful for anatomical information, but shouldn’t be the sole basis for surgery or long-term care.

If you experience your first episode of sciatica, the prognosis is favorable and you don’t need to have surgery. A vast majority of cases of acute sciatica respond well to conservative treatment and will improve significantly in 6 to 12 weeks, and in the case of non-compressive sciatica, it is often self-limiting.

If you experience your first episode of sciatica, the prognosis is favorable and you don’t need to have surgery. A vast majority of cases of acute sciatica respond well to conservative treatment and will improve significantly in 6 to 12 weeks, and in the case of non-compressive sciatica, it is often self-limiting.

Study at a Glance

The findings were important in a study of 283 patients that showed a link between MRI findings and treatment outcomes. The researchers compared those who had surgery early to those who were treated conservatively. In the conservative group, 55 ended up having surgery during their one-year visit, which illustrates the reality of treating this condition.

The main goal of the study was to see if certain MRI features, such as the size of the disc herniation, compression of the nerve roots, and intrusion of disc material into the spinal cord, could predict which patients would benefit from surgery and which would benefit from conservative therapy. The validated instruments used to measure outcomes were the Roland Disability Questionnaire (RDQ), a standard questionnaire that assesses the impact of back pain on daily activities, such as walking, sitting, dressing and lifting, and leg pain scores at 1 year.

The study unfolded in this way:

This is a timeline of the change in patient outcomes over the course of the study, and why time itself was one of the strongest variables.

Baseline – Study Entry (Weeks 0-6)

Trial Setup

283 patients suffering from severe sciatica for up to 3 months were divided into two groups: early surgical intervention (microdiscectomy) and prolonged conservative care. The lumbar disc herniations were confirmed by MRI in all participants. Baseline pain scores, RDQ scores, and neurological status were recorded.

The 3-Month Mark – Early Divergence

Faster Early Relief in the Surgical Group

The surgical patients experienced more rapid early pain relief and short-term functional gains. The data seemed to support surgery at this point. The bodies of the conservative group had already started the natural biological process of disc resorption, though, which is a progressive shrinking of the herniated tissue and the removal of inflammatory proteins by the immune system.

One Year Convergence – Outcomes Equalize

Equivalent Long-Term Recovery

The results of the two groups were similar at the 12-month follow-up. Most respondents in both groups experienced a significant recovery. The main conclusion of the study is that the convergence of these two treatments: surgical intervention led to more rapid early relief, while conservative management led to similar long-term results in most patients. It seems that time and nature have healing powers.

Patients who had nerve root compression on MRI had a higher rate of recovery than patients who did not have compression on MRI, and they had less pain at their 1-year follow-up appointment. It was interesting to see that this group had a reduction in back pain scores on the Roland Disability Questionnaire (RDQ). Patients with disc intrusion also had a higher rate of recovery and less leg pain at 1 year. Their RDQ scores were not however favourable, indicating that functional recovery and symptom relief are not necessarily correlated.

The size of the disc herniation was not directly correlated with the recovery rate. In the conservative group, there was no change in herniation size that influenced patient choice of surgery. A total of 21% of the participants were shown a large disc herniation. Interestingly, the larger herniation group did not have a good outcome in the surgical group either. The clinical expectations were not borne out by the data. The results were similar for those who had surgery and those who had long-term conservative treatment.

Two previous studies yielded similar findings that questioned physicians who heavily depended on imaging. One explanation is that sciatica can be both compressive and non-compressive in nature. If the sciatica is caused by chemical inflammation of the nerves, but not mechanical pressure, those experiencing the non-compressive type may experience a more unpredictable recovery of spontaneous resolution. Patients with definite nerve root compression seen on MRI, seemed to have a more favorable prognosis overall, perhaps due to the more specific nature of their pathology.

Obviously, MRI is not a reliable tool for making the decision for surgery versus conservative treatment. MRI, may be useful to predict prognosis when used in conjunction with clinical findings. It offers a window into inner anatomy, but the choice between surgery and non-surgical treatment should be based on imaging and symptoms, neurological exam, functional limitations, and patient values.

The research is important and reassuring for patients: an MRI scan that looks alarming doesn’t necessarily require surgery.
Important clinical implications are that:

Symptoms, physical examination findings, neurological deficits, and the impact of pain on daily function are as important, if not more important, than imaging in the decision making process and may provide a more meaningful outcome in many patients, even if their MRI is abnormal, Conservative care is a valid treatment option and treatment decisions should be individualized, incorporating imaging along with a careful clinical evaluation.

This is not to say that MRI is valueless. It is still important in excluding serious underlying causes of back pain, in identifying those patients that are surgical candidates with specific indications and in helping to make clinical decisions in the context of a comprehensive evaluation.

Conservative treatment is a viable option for most patients with sciatica caused by disc herniation, but surgery is an option in certain cases. This research should not discourage the need for necessary surgical treatment by patients or clinicians.

Surgery is usually recommended if:

• Muscle weakness is progressive and gets worse despite conservative treatment
• If cauda equina syndrome is present, it is a medical emergency with bowel or bladder dysfunction, as well as saddle anesthesia and bilateral leg weakness
• Severe neurologic deficits that are getting worse and not improving
• Disabling pain that is not relieved by an adequate course of evidence-based conservative treatment (usually 6–12 weeks of treatment)

In such instances, surgical consultation should be made early. The treatment of the cauda equina syndrome is time sensitive, with delay potentially leading to permanent neurological damage.

Early evaluation is important, if you have worsening neurological symptoms or any of the above warning signs. Your New York City spine doctor at NYDNRehab can help evaluate your symptoms and decide if you need urgent treatment.

Non-surgical treatment is the initial treatment of choice for the majority of patients with sciatica. There are several conservative treatments that have been shown to be effective, but treatment must be personalized.

Common conservative measures are:

• Physical therapy: specific exercise and manual therapy to decrease nerve irritation and function
• Exercise therapy: active rehabilitation including nerve mobilisations and core stability exercises , supported by simple at-home steps for how to relieve a pinched nerve
• Walking and activity modification: reasonable activity not complete bed rest, as shown to be non-beneficial by evidence
• Anti-inflammatory drugs: non-steroidal anti-inflammatory drugs (NSAIDs) and pain relievers for short-term pain relief (for a short period of time) under medical supervision
• Epidural steroid injections: may offer some relief of leg pain in certain patients for a short time, but the evidence for long-term benefit is moderate
• Patient education: knowledge of the natural history of sciatica helps to lower fear and promote active self-management
• Time and natural healing: many disc herniations shrink over time and symptoms often get better naturally as the disc shrinks

There is no one treatment for all people. Shared Decision Making is best practice with patients informed partners in their care.

Conservative care is not “waiting and hoping. It is logical and progressive in sequence. Here is an example of what evidence-based non-surgical management might look like in practice.

Step 1: Set up Your Diagnostic Baseline: Before imaging, before treatment.

Use a specialist to assess your motor strength, reflexes and nerve tension using clinical examination. Guidelines tend to recommend conservative management over MRI until there is progressive weakness or red flag symptoms. This is an assessment that will set you on the right path and help you make all subsequent decisions.

Step 2 Control Acute Inflammatory Pain Weeks 1 to 4

Focus on relative rest and avoid positions that will always cause leg symptoms. Take anti-inflammatory drugs as prescribed by a doctor for a short period of time to relieve symptoms. Start walking slowly and gently as soon as it is comfortable and not painful. Bed rest is not advised and may slow down healing.

Step 3: Begin Targeted Rehabilitation Weeks 4-8

Start active physical therapy directed toward your direction of motion, which is the direction that takes the pain away from the leg and back towards the lower back (centralization). At this stage, gentle movement of the sciatic nerve through its full range, known as nerve mobilization exercises, are often introduced, and there is emerging evidence that this can help reduce radicular symptoms.

Step 4 Build Structural Spine Resilience Weeks 8 and beyond

Progress to functional movement training, core stability and pelvic floor integration. The aim at this stage is not only to relieve the symptoms, but to create a solid foundation for long-term spine health, minimising the risk of re-herniation and restoring the body’s ability to function and return to work, sport and daily life.

A very puzzling thing for the patient is to get an MRI report that shows major abnormalities but the patient feels only mild symptoms or vice versa, severe symptoms with a relatively normal report. There are several mechanisms for this mismatch:

• Chemical nerve irritation: disc material contains inflammatory proteins such as phospholipase A2 and cytokines that can irritate nerve roots even if there is no mechanical compression
• Individual sensitivity to pain: there is a great deal of variation in the way people feel and respond to pain signals, which may be related to genetic, psychological, and social factors. Numerous MRI findings are not the cause of the current pain episode, but rather are pre-existing abnormalities
• Inflammation: nerve root inflammation may lead to major pain which may not be captured in structural imaging
• Persistent findings with functional recovery: if symptoms have resolved completely, but imaging shows a disc herniation, it may be a case of functional recovery despite the findings

That is why you may have different priorities for treatment in different patients even though you have the same MRI. Imaging is only part of the story, and structural anatomy and clinical experience make up the rest.

The majority of sciatica patients with lumbar disc herniation will improve in weeks to months. Studies have shown that between 80-90% of patients will improve without surgery in 6-12 weeks, but there is a wide variation in each patient’s individual progress.

Recovery factors are:

• Symptoms at presentation – severity and duration
• Neurological deficits (yes or no)
• Type of disc pathology (compressive vs. non-compressive)
• Fear-avoidance beliefs, psychological factors
• Active rehabilitation – engagement with rehabilitation.
• Overall health and lifestyle factors

Maintaining an appropriate activity level, within pain limits, is better than extended periods of rest. Repeat MRI scans are not usually recommended if symptoms are improving, as imaging results may not always reflect clinical recovery and may be distressing if there are still structural changes present that are not clinically significant.

• Inability to control bowel or bladder
• Numbness in the groin, inner thighs or genitals (saddle numbness)
• Leg weakness that is getting worse and worse quickly
• Sudden onset of severe neurological symptoms
• Back pain with fever, weight loss or night sweats
• Back pain after a major injury like a fall or accident

These symptoms can be a sign of cauda equina syndrome, spinal infection, fracture or malignancy which need immediate medical evaluation and treatment. Don’t wait to see if these symptoms get better on their own.

The MRI results are just one piece of the puzzle. A thorough clinical assessment of your symptoms, including imaging, neurological exam and functional status is unique to each patient and is essential to the treatment of sciatica.

NYDNRehab provides a full evaluation of the spine and sciatica in NYC, which uses evidence-based, non-surgical treatments specific to each patient’s presentation. If you’re dealing with a flare-up or have been experiencing symptoms for months, our experts can help you understand your options and help you create a clear path forward.

Providing services to patients throughout New York City and the surrounding area.