Sciatica Part 1: Understanding Its Many Causes
More than 25 years ago, sciatica transformed running from something I loved into a struggle simply to walk. A lumbar disc herniation at L5-S1 produced severe pain and neurological symptoms, forcing me to confront the condition from two perspectives: as a practitioner and as a patient.
My recovery required surgery, followed by manual therapy, progressive exercise, and a carefully planned return to activity. Within a year, I was able to compete in Ironman events again. That experience taught me something I have carried throughout my clinical career: sciatica is not a single diagnosis, and no single treatment is right for everyone.
The Good News
Sciatica can be intense, but most people do not require surgery. Many improve with time, appropriate activity, progressive exercise, education, and treatment directed toward the factors contributing to their symptoms. Manual therapy may also reduce pain and improve movement when integrated into a broader rehabilitation plan.
The first step is identifying what is producing the symptoms. Sciatic-type pain may arise from irritation of a spinal nerve root, but similar symptoms can also originate from the pelvis, hip, muscles, or peripheral nerves. The examination must therefore look beyond the location of the pain.
Surgery may be appropriate when there is progressive neurological loss, certain emergency findings, or severe symptoms that do not improve with appropriate conservative care. For everyone else, a clear diagnosis and an individualized rehabilitation plan provide a practical path forward.
Article Index:
What Does Sciatica Actually Mean?
Sciatica is a familiar term, but it is often used loosely to describe almost any pain travelling from the lower back into the leg. Clinically, it refers to symptoms associated with irritation or compression of neural structures that contribute to the sciatic nerve.
Most cases begin at a nerve root in the lower spine rather than within the sciatic nerve itself. Symptoms may include:
Pain extending into the buttock, thigh, calf, or foot
Tingling or altered sensation
Numbness
Muscle weakness
Changes in reflexes
Pain may be sharp, burning, electric, aching, or difficult to describe. Some people experience leg symptoms without significant lower back pain.
The Sciatic Nerve:
The sciatic nerve:
Receives fibres from the L4 to S3 spinal nerve roots
Forms from the lumbosacral plexus within the pelvis
Passes through the gluteal region and continues down the back of the thigh
Divides into the tibial and common fibular nerves, usually near the knee
It is the largest peripheral nerve in the body and can approach the width of an adult thumb.
Sciatica, Radicular Pain, and Radiculopathy
These terms are related, but they are not interchangeable:
Sciatica is a general clinical term for pain and other symptoms travelling along the sciatic pathway.
Radicular pain occurs when a spinal nerve root becomes irritated or inflamed, producing pain that travels into the leg.
Radiculopathy involves measurable loss of nerve function, such as weakness, reduced sensation, or altered reflexes.
Referred pain can travel into the buttock or leg from spinal joints, discs, muscles, or other tissues without nerve-root dysfunction.
Sciatic neuropathy results from injury or irritation of the sciatic nerve after it has formed and is less common than nerve-root involvement.
Symptoms do not always follow the clean dermatome diagrams shown in textbooks. Dermatomes overlap, people vary, and radicular pain frequently extends beyond a single textbook pattern. For this reason, diagnosis should not depend on pain location alone.
The distribution of symptoms provides useful clues, but history, neurological examination, mechanical testing, and imaging when indicated must be considered together.
Where Sciatic Symptoms Begin
Sciatic symptoms can originate at several points along the neural pathway. Common causes include lumbar disc herniation, narrowing around a spinal nerve root, spinal stenosis, and less commonly, irritation of the sciatic nerve within the pelvis or gluteal region.
This section focuses on two important sources: lumbar disc herniation and nerve entrapment outside the spine.
Lumbar Spinal Discs
Five intervertebral discs are located between the lumbar vertebrae and the sacrum, from L1-L2 to L5-S1. These adaptable structures distribute load, permit movement, and help the spine respond to compression.
Each disc contains:
The annulus fibrosus, a layered outer ring of collagen
The nucleus pulposus, a water-rich inner region that helps distribute pressure
Changes in a disc can sometimes irritate a nearby nerve root through mechanical pressure, inflammation, or a combination of both. The L4-L5 and L5-S1 levels are most commonly involved.
Understanding Disc Terminology
Imaging reports use several terms to describe disc shape:
Disc degeneration: Changes in disc hydration, structure, or height that commonly develop with age. These findings may or may not be related to pain.
Disc bulge: A broad extension of the disc beyond its usual boundary. A bulge is not necessarily a herniation and often causes no symptoms.
Disc protrusion: A localized herniation in which the base remains wider than the portion extending outward.
Disc extrusion: A herniation in which disc material extends farther beyond its base or loses continuity with the disc.
These terms describe what the disc looks like, not how much pain a person should feel. A small herniation can produce substantial symptoms when it irritates a nerve root, while a larger one may cause few or no symptoms.
The Scan Is Only Part of the Diagnosis
Disc bulges and degenerative changes are commonly found in people without pain. Even a visible herniation does not establish that the disc is responsible for the symptoms.
Its clinical importance depends on whether the imaging corresponds with:
The distribution of pain and altered sensation
Muscle strength and reflex findings
Nerve-tension testing
Movements or positions that change the symptoms
The person’s functional limitations
Most people with sciatica related to lumbar disc herniation improve without surgery. Staying appropriately active, gradually restoring movement and strength, and monitoring neurological function are central to recovery. Manual therapy may support pain reduction and movement when selected according to the examination findings.
Surgical assessment becomes more important when neurological function progressively deteriorates, emergency symptoms appear, or severe disabling symptoms persist despite appropriate nonsurgical care.
When Sciatica Requires Urgent Care
Most sciatica is not caused by a medical emergency. However, certain symptoms may indicate significant nerve compression or another serious condition requiring immediate assessment.
Seek Emergency Care Immediately
Go to an emergency department if sciatica is accompanied by:
New difficulty starting or controlling urination, inability to feel bladder fullness, or loss of bowel control
Numbness around the genitals, anus, inner thighs, or the area that would contact a saddle
Rapidly developing or severe weakness in one or both legs
Symptoms affecting both legs, particularly when combined with numbness, weakness, or bladder and bowel changes
Severe back or leg pain following significant trauma
These symptoms may indicate cauda equina syndrome, severe neurological compromise, or a spinal fracture. Rapid assessment is important because delayed treatment can lead to permanent loss of function.
Arrange Prompt Medical Assessment
Contact a healthcare provider promptly if you develop:
Weakness that is new or progressively worsening
Increasing difficulty walking or repeated falls
Fever, chills, or recent infection accompanying back or leg pain
Severe pain following a minor fall when osteoporosis or fracture risk is present
Unexplained weight loss, a history of cancer, or persistent pain that is severe at night
Symptoms that continue to worsen rather than gradually improve
For practitioners, red flags should be interpreted within the full clinical context. Their significance depends on onset, progression, associated neurological findings, trauma history, infection or cancer risk, medication use, and overall health.
When serious pathology is suspected, treatment should be deferred and the patient referred for appropriate medical investigation.
Disc Herniation: Two Myths Worth Leaving Behind
An MRI can provide valuable anatomical information, but it cannot predict the entire course of sciatica. Two persistent myths can make an imaging report sound far more final than it really is.
Myth 1: A Large Herniation Means Nonsurgical Care Will Fail
Reality
The size of a disc herniation does not determine treatment by itself. Surgery can provide faster relief for some carefully selected patients, particularly when leg pain is severe or neurological function is deteriorating. However, many people improve with education, appropriate activity, progressive exercise, medication when needed, and other nonsurgical care.
Over the longer term, differences between surgical and nonsurgical outcomes often become smaller. The decision must therefore consider the complete clinical picture rather than the MRI alone.
Myth 2: Extruded or Sequestered Fragments Cannot Regress
Reality
Disc extrusions and sequestrations often appear more dramatic on imaging, yet they are more likely to regress than contained protrusions. Once disc material is exposed outside its usual boundaries, the immune system may recognize it and begin breaking it down. Macrophages, inflammatory signalling, and the development of small blood vessels can contribute to gradual resorption.
This process may reduce the size of the herniation over time. However, improvement on an MRI and improvement in symptoms do not always occur together. A person may feel considerably better before the scan changes, while another may continue to experience symptoms despite radiological regression.
The Clinical Perspective
Disc shape and size matter, but they are only part of the assessment. Treatment decisions should also consider:
Pain severity and functional limitations
Muscle strength, sensation, and reflexes
Whether neurological findings are stable or worsening
The duration and progression of symptoms
The response to appropriate nonsurgical care
The patient’s goals, preferences, and tolerance of risk
Urgent surgical assessment is required when cauda equina syndrome or rapidly progressive neurological loss is suspected. In the absence of these findings, the MRI should guide clinical reasoning, not dictate it.
The key message is simple: a large disc herniation is an important finding, but it is not a prediction of failure.
What Part 1 Teaches Us
Experiencing sciatica as both a patient and a practitioner taught me how profoundly it can affect movement, sleep, work, sport, and confidence. It also taught me that even severe symptoms do not tell us everything about the eventual outcome.
Sciatica is not a single condition with a single solution. Symptoms may arise from nerve-root irritation, disc herniation, spinal narrowing, or irritation elsewhere along the sciatic pathway. A large finding on an MRI can be clinically important, but it does not automatically predict persistent pain, neurological loss, or the need for surgery.
Most people with disc-related sciatica improve without surgery. Recovery may include education, appropriate activity, progressive exercise, medication when needed, and manual therapy selected according to the examination findings. Surgery remains important when emergency symptoms, progressive neurological loss, or persistent disabling symptoms make it the appropriate choice.
My own recovery required surgery followed by manual therapy, exercise, and a progressive return to training. Someone else’s path may be very different. The essential lesson is that treatment should be guided by the cause, neurological findings, functional limitations, and the individual, not by the diagnostic label alone.
In Sciatica Part 2: Beyond the Spine, we will examine less common sources of sciatic-type symptoms, including deep gluteal and peripheral nerve entrapments. We will also explore how orthopedic and neurological examinations help distinguish nerve-root involvement from other causes of pain travelling into the
References - Part 1
Brinjikji, W., Luetmer, P. H., Comstock, B., Bresnahan, B. W., Chen, L. E., Deyo, R. A., Halabi, S., Turner, J. A., Avins, A. L., James, K., Wald, J. T., Kallmes, D. F., & Jarvik, J. G. (2015). Systematic literature review of imaging features of spinal degeneration in asymptomatic populations. American Journal of Neuroradiology, 36(4), 811–816.
Chiu, C. C., Chuang, T. Y., Chang, K. H., Wu, C. H., Lin, P. W., & Hsu, W. Y. (2015). The probability of spontaneous regression of lumbar herniated disc: A systematic review. Clinical Neurology and Neurosurgery, 134, 61–66.
Fardon, D. F., Williams, A. L., Dohring, E. J., Murtagh, F. R., Rothman, S. L. G., & Sze, G. K. (2014). Lumbar disc nomenclature: Version 2.0. Recommendations of the combined task forces of the North American Spine Society, the American Society of Spine Radiology, and the American Society of Neuroradiology. The Spine Journal, 14(11), 2525–2545.
Gugliotta, M., da Costa, B. R., Dabis, E., Theiler, R., Jüni, P., Reichenbach, S., Landolt, H., & Hasler, P. (2016). Surgical versus conservative treatment for lumbar disc herniation: A prospective cohort study. BMJ Open, 6(12), e012938.
Jensen, M. C., Brant-Zawadzki, M. N., Obuchowski, N., Modic, M. T., Malkasian, D., & Ross, J. S. (1994). Magnetic resonance imaging of the lumbar spine in people without back pain. New England Journal of Medicine, 331(2), 69–73.
Koes, B. W., van Tulder, M. W., & Peul, W. C. (2007). Diagnosis and treatment of sciatica. BMJ, 334(7607), 1313–1317.
Liu, C., Ferreira, G. E., Abdel Shaheed, C., Chen, Q., Harris, I. A., Bailey, C. S., Peul, W. C., Koes, B., & Lin, C. W. C. (2023). Surgical versus non-surgical treatment for sciatica: Systematic review and meta-analysis of randomised controlled trials. BMJ, 381, e070730.
Ropper, A. H., & Zafonte, R. D. (2015). Sciatica. New England Journal of Medicine, 372(13), 1240–1248.
Taylor, C. S., Coxon, A. J., Watson, P. C., & Greenough, C. G. (2013). Do L5 and S1 nerve root compressions produce radicular pain in a dermatomal pattern? Spine, 38(12), 995–998.
Disclaimer:
The articles and embedded videos on the MSR website are provided for educational and informational purposes only. They are not a substitute for individualized assessment, diagnosis, or treatment by an appropriately qualified healthcare professional.
Some videos demonstrate clinical examination and manual therapy procedures intended for licensed or regulated healthcare professionals with appropriate training. These procedures should be performed only within the practitioner’s legal scope of practice and should not be attempted as self-treatment.
Viewing or using this content does not establish a practitioner-patient relationship. If you have questions about a medical condition or symptoms that are new, severe, or worsening, consult an appropriately qualified healthcare provider.
MSR is not responsible for decisions made or actions taken solely on the basis of this educational content. For complete information about website use, third-party links, privacy, and legal terms, please review the MSR Terms of Use, Privacy Policy, and full website disclaimer.
DR. BRIAN ABELSON, DC. - The Author
Dr. Brian Abelson is a chiropractor, author, and educator with more than 30 years of clinical experience in musculoskeletal care, rehabilitation, and sports performance. His educational work focuses on musculoskeletal conditions, human movement, sports biomechanics, and evidence-informed approaches to treatment and rehabilitation.
He is the developer of Motion Specific Release (MSR) and Clinical Director of Kinetic Health in Calgary, Alberta, Canada.
Continue Learning with MSR Courses and MSR Pro
For Healthcare Practitioners
Motion Specific Release integrates assessment, clinical reasoning, manual therapy, exercise, and patient education within one adaptable approach to musculoskeletal care.
MSR Pro and MSR courses support different parts of that learning process:
Structured Clinical Education: MSR courses connect applied anatomy and biomechanics with orthopedic and neurological assessment, myofascial procedures, fascial expansions, joint mobilization, manipulation, and rehabilitation.
Hands-On Skill Development: Live training provides opportunities to refine palpation, patient positioning, force application, and clinical decision-making through practice and direct feedback.
MSR Pro Clinical Library: Members receive access to more than 200 MSR procedures, downloadable and fillable clinical forms, examination resources, rehabilitation progressions, and exercise-prescription materials.
Extensive Video Resources: More than 800 videos support examination, treatment procedures, exercise rehabilitation, and clinical application.
Patient Education: A library of 50 condition articles helps practitioners explain common musculoskeletal problems and provide patients with practical information.
Continued Development: Resources are updated as MSR courses and clinical education continue to evolve.
Videos and articles can introduce concepts, but hands-on proficiency develops through deliberate practice, feedback, and experience. MSR is designed to help practitioners connect technique with clinical reasoning and adapt care to the individual rather than apply the same protocol to everyone.
Explore MSR Pro | View Online and Live Courses
Comments