WHAT IS SCIATICA AND SCIATIC NEUROPATHY?
ABSTRACT
Sciatica, sciatic paresthesia, and neuropathy are interconnected conditions that affect the nervous system, often resulting in significant discomfort and impaired mobility. Understanding the distinctions and connections between these conditions is essential for effective diagnosis and treatment, as each requires a tailored approach to manage symptoms and address the underlying causes. This article explores the causes, symptoms, and treatment options for sciatica, sciatic paresthesia, and neuropathy, providing insights into how they impact the nervous system and overall quality of life.
Dr. Gregory Lawton
WHAT IS SCIATICA AND SCIATIC NEUROPATHY?
Sciatica is a broad term commonly used to describe nerve pain that radiates along the path of the sciatic nerve, which runs from the lower back through the hips and down each leg. This condition is typically characterized by pain that travels from the lower back or buttocks down the back of the leg, often reaching as far as the foot. The pain can range from mild to severe and is sometimes accompanied by tingling, numbness, or muscle weakness in the affected leg.
Despite its widespread use, the term 'sciatica' is often considered outdated by many healthcare professionals because it lacks specificity. The term doesn't pinpoint the underlying cause of the nerve pain, which can arise from various issues, including a herniated disc, spinal stenosis, or piriformis syndrome, among others. Because of this, the term 'sciatica' may not be sufficient to guide effective treatment, as it doesn't address the root cause of the symptoms.
Sciatica is a common condition, with research indicating that approximately 60% of individuals who suffer from back pain also experience leg pain associated with this nerve condition. However, the exact cause and presentation can vary significantly from one person to another, making a precise diagnosis and targeted treatment plan essential for effective management.
There are three primary causes of pain at the back of your leg: referred pain, radicular pain, and radiculopathy.
Referred pain occurs when pain is perceived at a location other than where the injury or issue originated. This type of pain is often poorly localized and arises from muscles, joints, ligaments, or other non-nerve structures. For instance, visceral pain originating from an internal organ like the liver can be felt in a different area, such as the shoulder.
The Sciatic Nerve
Radicular pain is characterized by a sharp, shooting, or 'bright' sensation that typically follows a specific nerve pathway. Under normal circumstances, nerves transmit signals from peripheral areas, such as your skin or joints, to your spinal cord and brain. However, in the case of radicular pain, the nerve signal is triggered at the nerve root near the spine, rather than from the peripheral receptors.
Radicular pain can potentially lead to or be associated with neuropathy, but they are distinct conditions with different underlying mechanisms.
Radicular pain occurs when a nerve root near the spine is compressed, irritated, or inflamed. This compression or irritation can result in pain that radiates along the path of the nerve, often following a specific pattern corresponding to the nerve's distribution. Common causes of radicular pain include herniated discs, spinal stenosis, or bone spurs.
Neuropathy, on the other hand, refers to damage or dysfunction of peripheral nerves, which can result in symptoms such as pain, numbness, tingling, and muscle weakness. Neuropathy can be caused by a variety of factors, including diabetes, infections, certain vaccines, trauma, chemotherapy, and certain medications.
Radicular pain itself doesn't directly cause neuropathy, but if the underlying cause of radicular pain (such as nerve compression) is left untreated, it can lead to nerve damage over time. This nerve damage could potentially result in neuropathic symptoms, such as chronic pain or loss of sensation, which are characteristic of neuropathy.
In some cases, prolonged or severe radicular pain may indicate nerve damage that could evolve into a form of neuropathy if not managed properly. Therefore, it's important to address the underlying causes of radicular pain early to prevent potential nerve damage and the development of neuropathic conditions.
Illustration Example of a Lumbar Herniated Disc
Neuropathy May Present With Differing Symptoms
Lastly, radiculopathy refers to a loss of function resulting from an injury to the nerve root. Interestingly, pain is not a required criterion for diagnosing radiculopathy.
In practice, these conditions often overlap. For instance, it's common to experience a painful radiculopathy or radicular pain alongside referred pain. This overlap may help explain why the term 'sciatica' has continued to be used despite its limitations.
A person can have both radiculopathy and neuropathy at the same time, though they are distinct conditions with different causes and characteristics. Having both conditions can complicate diagnosis and treatment, as the symptoms can overlap and intensify. Therefore, a thorough evaluation is essential to differentiate between the two and to address the underlying causes effectively.
WHAT CAUSES SCIATIC NERVE PAIN OR PARAESTHESIA?
Sciatic nerve pain can result from two primary types of nerve injury: mechanical pressure and chemical irritation.
Mechanical pressure can be categorized into three types: crowding, bowstringing, and compression. Many people envision a bulging disc pressing against a nerve as the typical cause of sciatica. While this severe compression can occur, it is less common than often assumed. In some cases, a nerve can be stretched and thinned, leading to a bowstringing effect that compromises nerve function. Nerves also pass through areas crowded with other structures, which can displace and injure the nerve due to increased pressure.
Chemical irritation is another, often overlooked, cause of nerve injury. The body usually keeps different structures separate to prevent inflammation and irritation. However, when an injury occurs, substances that normally don't interact can come into contact, triggering an inflammatory response. These chemicals can irritate structures like the nerve root, leading to symptoms of sciatica.
WHY DO I EXPERIENCE THESE NERVE SYMPTOMS?
In some cases, nerve symptoms can be traced back to a specific injury. However, identifying the exact cause can sometimes be challenging. This difficulty arises because some nerve injuries develop gradually over time. For instance, bony changes in the spine that crowd the nerve or a slow, progressive bowstringing effect from a disc herniation may take months to manifest symptoms, making it hard to link them to a specific incident.
A very common and often overlooked cause of nerve pain and paresthesia is the result of heart and artery disease where the blood flow to the spine is compromised due to blocked arteries. This results in a gradual degeneration of the spine, its discs, and ligaments.
Nerves are delicate structures that depend on adequate blood flow and oxygen to function properly. When mechanical pressure is applied, it can restrict or even completely block blood flow, leading to a loss of nerve conduction in conditions like radiculopathy, or the creation of abnormal nerve signals that result in pain, as seen in radicular pain. This restriction of blood flow and oxygen, known as ischemia, can contribute to the development of these nerve symptoms.
A common example of this sensation is when your arm or leg 'goes numb.' If you sit or lie on a limb for an extended period without moving, blood flow to the nerve can be disrupted. The limb may feel 'dead,' and you temporarily lose voluntary control until blood flow and nerve conduction are restored. In most cases, this conduction block is reversible if it’s brief. However, if the disruption persists, the lack of oxygen can damage the nerve, potentially leading to permanent injury.
Chemical irritation can also interfere with nerve conduction. This occurs when immune cells from the inflammatory response break down the nerve's protective layers, further compromising its function
Blood Flow to a Nerve
Source: Ananda Weerasuriya, MPhil, PhD Mercer University School of Medicine, Macon, GA · Basic Medical Sciences
The image above is a cross-sectional diagram of a peripheral nerve, illustrating the blood supply and various connective tissue layers that surround and protect the nerve fibers. The labeled structures include the endoneurium (Endo), perineurium (Peri), and epineurium (Epi), which are the three layers of connective tissue that encapsulate individual nerve fibers, fascicles (bundles of fibers), and the entire nerve, respectively. The blood vessels labeled as RV and EV supply the nerve with essential nutrients and oxygen.
WHAT ARE THE RISK FACTORS FOR DEVELOPING NERVE PAIN?
Nerve pain, including sciatica, can be influenced by a variety of risk factors. Understanding these factors can help in both preventing and managing symptoms. Some of the most common risk factors include:
Overweight or Obesity: Excess body weight puts additional pressure on the spine and nerves, increasing the risk of nerve compression, particularly in the lower back.
Core Muscle Atrophy and Back Muscle Hypertonicity: Core muscle atrophy, which weakens the support for the spine, combined with hypertonicity (excessive tightness) of the back muscles, can create imbalances that place undue stress on the lower back, leading to chronic pain and increased vulnerability to injury.
Sedentary Lifestyle: Lack of regular physical activity can lead to weakened muscles and poor spinal support, making you more susceptible to nerve pain. Prolonged sitting, especially with poor posture, can exacerbate this risk.
Heart and Artery Disease: Cardiovascular conditions can affect blood flow to nerves, leading to ischemia (restricted blood supply) and increasing the likelihood of nerve pain.
Smoking: Smoking reduces blood flow and oxygen to the tissues, including nerves, which can contribute to the development of nerve pain and slow down the healing process.
Alcohol Consumption: Excessive alcohol intake can damage nerves directly and also lead to nutrient deficiencies, particularly in B vitamins, which are crucial for nerve health.
Degenerative Diseases: Conditions like arthritis can cause wear and tear on the joints and spine, leading to nerve compression and inflammation, which can trigger nerve pain.
Spinal Injury or Trauma: Any injury to the spine, such as from a fall, accident, or heavy lifting, can damage nerves directly or lead to structural changes that put pressure on nerves.
Pregnancy: Weight gain and changes in posture during pregnancy can increase pressure on the spine and pelvic area, sometimes leading to sciatic nerve pain.
Poor Posture: Chronic poor posture can strain the spine and muscles, leading to imbalances and nerve compression over time.
Depression: Mental health conditions like depression can exacerbate the perception of pain, including nerve pain, and may lead to behaviors, such as physical inactivity, that increase the risk.
Stress: Chronic stress can cause muscle tension and inflammation, which may contribute to nerve compression and pain. Stress can also negatively affect sleep, further compounding nerve pain issues.
Other factors that may increase the risk of developing nerve pain include genetic predispositions, chronic illnesses like diabetes (which can cause neuropathy), and occupational hazards such as exposure to toxic substances as well as repetitive motions or heavy lifting. Understanding and managing these risk factors can play a crucial role in preventing and alleviating nerve pain.
What are the best treatment strategies for preventing and managing radiculopathy and neuropathy?
1. Weight Management
Why: Excess body weight can place additional pressure on the spine and nerves, leading to nerve compression.
Strategy: Maintaining a healthy weight through a balanced diet and regular exercise can reduce the strain on the spine and decrease the risk of nerve pain. Incorporate activities that strengthen core muscles, as they support the spine.
2. Physical Activity and Exercise
Why: A sedentary lifestyle can weaken muscles and reduce spinal support, increasing susceptibility to nerve pain.
Strategy: Engage in regular physical activity, including exercises that improve flexibility, strength, and cardiovascular health. Activities such as walking, swimming, tai chi chuan, and yoga are particularly beneficial. It’s also essential to avoid prolonged sitting and practice good posture.
3. Cardiovascular Health
Why: Heart and artery disease can limit blood flow to nerves, leading to ischemia and nerve pain. Strategy: Adopt a heart-healthy lifestyle by eating a diet rich in fruits, vegetables, whole grains, and lean proteins. Regular cardiovascular exercise and avoiding smoking are crucial. Managing conditions like hypertension and high cholesterol is also important.
4. Smoking Cessation
Why: Smoking reduces blood flow and oxygen to tissues, including nerves, which can exacerbate nerve pain and hinder healing.
Strategy: Quitting smoking is one of the most effective ways to improve overall vascular health and reduce nerve pain. Support from cessation programs, medications, or counseling can be beneficial.
5. Stop Drinking Alcohol
Why: Alcohol consumption can directly damage nerves and lead to nutrient deficiencies, particularly in B vitamins, which are vital for nerve health.
Strategy: Eliminate alcohol consumption to protect nerve health. If alcohol use is a concern, consider seeking support from healthcare professionals or support groups.
6. Managing Degenerative Diseases
Why: Conditions like arthritis can cause joint and spinal degeneration, leading to nerve compression and inflammation.
Strategy: Regular medical check-ups, physical therapy, and medications to manage arthritis can help reduce the risk of nerve pain. Joint-friendly exercises, such as swimming, can also help maintain mobility without stressing the joints.
7. Injury Prevention
Why: Trauma to the spine can lead to nerve damage or structural changes that increase the risk of nerve compression.
Strategy: Practice safe lifting techniques, use ergonomic furniture, and engage in activities that strengthen the back and core muscles to protect the spine from injury.
8. Posture Improvement
Why: Poor posture can strain the spine and muscles, leading to nerve compression over time. Strategy: Maintain good posture, particularly when sitting or standing for long periods. Ergonomic adjustments to your work environment and exercises that strengthen postural muscles can help.
9. Mental Health Support
Why: Depression and stress can exacerbate the perception of pain and lead to behaviors that increase the risk of nerve pain.
Strategy: Engage in stress-reduction techniques such as mindfulness, meditation, or counseling. Addressing mental health conditions with professional support can also help reduce the overall burden of nerve pain.
10. Nutritional Support
Why: Proper nutrition supports overall health and nerve function, especially concerning the prevention of nutrient deficiencies that can lead to nerve damage.
Strategy: Ensure a diet rich in vitamins, particularly B vitamins, which are crucial for nerve health. Consider supplements if recommended by a healthcare provider.
11. Regular Health Check-ups
Why: Chronic illnesses, such as diabetes, can cause neuropathy if left unmanaged.
Strategy: Regular monitoring and management of chronic conditions, such as blood sugar levels in diabetes, can prevent the onset of nerve damage.
By addressing these risk factors with tailored strategies, individuals can significantly reduce the likelihood of developing nerve pain or manage existing conditions more effectively. Regular consultation with healthcare providers is essential to create a personalized care plan that addresses specific needs and health conditions.
The Author
Dr. Gregory T. Lawton is the author of over a hundred books and educational materials. In 1980 he founded the Blue Heron Academy, a state licensed vocational school that offers classes in traditional and conventional health care. He is an award-winning artist and photographer. Dr. Lawton is a licensed chiropractor, licensed naprapath, and a licensed acupuncturist. He is nationally board certified in physiotherapy, radiology, chiropractic, and acupuncture.
He has trained in several martial arts including Kosho Ryu Kenpo Jujitsu, in which he holds a 9th degree black belt, Tai Chi Chuan, Pakua Chang, and Hsing Yi Chuan. Dr. Lawton has been a member of the Baha’i Faith since 1970.