A note on this column: This article is general medical information, not a description of a service offered at this practice. Dr. Ishiguro's surgical practice is focused on hip and knee conditions — he does not treat or perform surgery for sciatica or other spinal conditions. This column is written to help readers understand a common condition and know when and how to seek the right specialist, typically a spine-focused orthopaedic surgeon or neurosurgeon.
What sciatica actually is
"Sciatica" isn't a diagnosis in itself — it's a description of a symptom pattern: pain that radiates along the path of the sciatic nerve, which runs from the lower back through the buttock and down the back of the leg. It happens when a nerve root in the lower spine (most often at the L4-L5 or L5-S1 level) is compressed or irritated. The most frequent underlying cause is a herniated (or "slipped") disc pressing on a nerve root, but degenerative changes such as spinal stenosis (narrowing of the space around the nerves) or facet joint osteoarthritis can produce the same pattern of leg-dominant pain, particularly in older patients.
The key clinical clue that distinguishes sciatica from ordinary low back pain is that the leg pain is usually as bad as, or worse than, the back pain itself, and it typically follows a nerve's path rather than staying localized to the spine.
How common it is
Sciatica is common, but pinning down exactly how common has proven surprisingly difficult for researchers. A widely cited review of epidemiological studies found that reported point prevalence for sciatica-type symptoms ranged enormously across studies — from roughly 1% to over 40% — largely because different studies use different definitions of "sciatica," from self-reported leg pain to nerve-root-confirmed radiculopathy. Lifetime incidence is generally estimated at somewhere between 13% and 40% of adults. Prevalence rises with age through midlife, peaking roughly between ages 45 and 64, and several studies have found it affects men somewhat more often than women.
Established risk factors
- Middle age — most commonly develops between roughly 30 and 50 years old, before degenerative changes become the dominant cause in later life
- Occupational lumbar load — repeated forward bending, heavy lifting, and manual materials handling are consistently linked to higher risk
- Smoking — associated with increased risk, possibly through effects on disc nutrition and healing
- Higher body mass index — added mechanical load on the lumbar spine
- Prolonged sitting and vibration exposure — implicated in several occupational studies, notably among professional drivers
Symptoms
Typical sciatica presents as pain radiating from the lower back or buttock down the back or side of one leg, sometimes reaching below the knee to the foot. It's often accompanied by numbness, tingling ("pins and needles"), or a burning sensation along the same path, and can be worsened by sitting, coughing, sneezing, or straining. Some patients also notice mild weakness — for example, difficulty pushing off with the foot or lifting the toes — which reflects the specific nerve root being affected rather than a general muscle problem.
Most episodes of sciatica caused by a disc herniation improve substantially within six to twelve weeks with time and conservative care, which is an important point patients are often not told early on.
Warning signs that need urgent attention: New loss of bladder or bowel control, numbness in the saddle area (inner thighs, groin), or rapidly worsening weakness in both legs can indicate cauda equina syndrome — a rare but genuine spinal emergency requiring same-day evaluation, not a routine outpatient visit.
How the diagnosis is made
Diagnosis begins with a history and physical exam, including neurological testing of strength, reflexes, and sensation in specific patterns that help identify which nerve root is involved. The straight leg raise test — lifting the patient's straight leg while lying down and noting whether it reproduces the radiating leg pain below the knee — remains one of the most widely used bedside tests, though its accuracy has real limits.
What the evidence shows: A systematic review pooling data on the straight leg raise test found a pooled sensitivity of 0.91 but a pooled specificity of only 0.26 when surgical findings were used as the reference standard (Devillé et al., Spine, 2000). In plain terms, the test is good at not missing a true disc herniation when it's positive, but a positive result alone is a poor way to rule other causes out — a substantial share of positive tests occur in people without a surgically confirmed herniation. This is why the test is used alongside the rest of the clinical picture and imaging, not as a standalone diagnostic tool.
Imaging is not needed for every episode of sciatica, particularly early on when conservative treatment is the reasonable first step regardless of what a scan would show. It becomes more important when symptoms are severe, progressive, associated with significant weakness, persist beyond six weeks of conservative care, or when surgery is being considered.
| Method | Strengths | Limitations |
|---|---|---|
| MRI | Detailed view of disc, nerve root, and soft tissue; no radiation; the standard for surgical planning | Higher cost, longer scan time; can show incidental findings unrelated to symptoms |
| CT | Faster, useful when MRI is contraindicated (e.g., certain implanted devices); good bone detail | Radiation exposure; less detailed soft-tissue and nerve visualization than MRI |
| X-ray | Quick, low cost, useful for alignment, instability, or bone-related causes | Cannot directly visualize disc herniation or nerve compression |
What the evidence says about treatment
Most cases of sciatica caused by a disc herniation are managed successfully without surgery, and a natural biological process helps explain why: herniated disc material frequently shrinks or resolves on its own over time.
What the evidence shows: A systematic review of imaging follow-up studies found that spontaneous regression occurred in a majority of more severe herniation types — about 96% of sequestrated fragments and 70% of extruded discs showed some regression on repeat imaging, with complete resolution in 43% and 15% of those groups respectively (Chiu et al., Clinical Rehabilitation, 2015). Less severe bulges and protrusions regressed less often. This helps explain why many patients improve over weeks to months without any procedure — the mechanical cause of the compression can shrink on its own — though it doesn't mean every patient's case will follow this course.
Commonly used treatment options
- Staying active within tolerance — current guidance favors continuing normal activity as much as pain allows, rather than prolonged bed rest, which is no longer recommended
- Anti-inflammatory or other pain-relief medication — used for symptom control during the acute phase
- Physical therapy — exercises targeting core and spinal stability, along with nerve-gliding and flexibility work, once the acute pain begins to settle
- Epidural steroid injection — an injection of corticosteroid around the affected nerve root, sometimes used for significant pain that hasn't responded to initial conservative measures; evidence generally supports short-term pain relief more consistently than long-term benefit
- Microdiscectomy — a minimally invasive surgical procedure to remove the portion of disc material compressing the nerve root, generally reserved for patients with significant, persistent symptoms after a genuine trial of conservative care, or for those with progressive neurological deficit
The question of whether and when to move to surgery has been studied directly in a well-known randomized trial from the Netherlands.
What the evidence shows: A randomized controlled trial of 283 patients with 6 to 12 weeks of sciatica from a confirmed disc herniation compared early surgery with prolonged conservative treatment (with surgery available later if needed). At one year, both strategies led to similar rates of perceived recovery, though patients assigned to early surgery reported faster relief of leg pain in the initial months (Peul et al., N Engl J Med, 2007). Five-year follow-up of the same cohort found no significant difference between the groups on the main outcome measures. In practice, this supports what many spine specialists already do: a reasonable trial of conservative care is a sound starting point for most patients, while earlier surgery remains a legitimate option for well-informed patients who want faster relief or whose symptoms are more severe, since outcomes at one year and beyond were broadly comparable either way.
When to see a specialist
Leg pain that follows a nerve pattern and hasn't meaningfully improved after several weeks of self-care, pain severe enough to disrupt sleep or daily function, or any new weakness — such as a foot that seems to drag or difficulty standing on tiptoe — are reasonable reasons to seek a spine specialist's evaluation rather than waiting indefinitely. As noted above, loss of bladder or bowel control or saddle-area numbness is different: that combination warrants emergency care the same day, not a scheduled outpatient appointment.
References (PubMed / Journal)
Konstantinou K, Dunn KM. Sciatica: review of epidemiological studies and prevalence estimates. Spine (Phila Pa 1976). 2008;33(22):2464-2472. DOI: 10.1097/BRS.0b013e318183a4a2
Devillé WL, van der Windt DA, Dzaferagić A, Bezemer PD, Bouter LM. The test of Lasègue: systematic review of the accuracy in diagnosing herniated discs. Spine (Phila Pa 1976). 2000;25(9):1140-1147. PubMed: PMID 10788860
Chiu CC, Chuang TY, Chang KH, Wu CH, Lin PW, Hsu WY. The probability of spontaneous regression of lumbar herniated disc: a systematic review. Clin Rehabil. 2015;29(2):184-195. DOI: 10.1177/0269215514540919
Peul WC, van Houwelingen HC, van den Hout WB, et al. Surgery versus prolonged conservative treatment for sciatica. N Engl J Med. 2007;356(22):2245-2256. DOI: 10.1056/NEJMoa064039