Both lumbar radiculopathy and deep gluteal syndrome can produce buttock and leg symptoms along the sciatic distribution. The difference is the site of nerve irritation. Lumbar radiculopathy involves a spinal nerve root; deep gluteal syndrome involves the sciatic nerve after it has left the pelvis. The distinction comes from the history, neurologic exam, lumbar loading, neurodynamic testing, deep-gluteal provocation, strength, reflexes and imaging when needed.
Why "sciatica" is not a diagnosis
Sciatica describes where symptoms travel, not what is causing them. The sciatic nerve is formed from lumbar and sacral nerve roots, leaves the pelvis through the greater sciatic notch, runs beneath the gluteus maximus and continues down the back of the thigh. Irritation anywhere along that path can produce similar buttock and leg symptoms. A disc herniation, spinal stenosis, entrapment in the deep gluteal space and proximal hamstring problems can all present as "sciatica".
Lumbar radiculopathy: irritation at the nerve root
Lumbar radiculopathy means a lumbar or sacral nerve root is irritated or compressed inside the spine, most often by a disc herniation or by narrowing from stenosis. Features that make it more likely include:
- Symptoms following a dermatome or nerve-root pattern, often below the knee
- Weakness in the muscles supplied by one root
- Reflex asymmetry, such as a reduced ankle reflex
- Sensory change in a root distribution
- Symptoms that change with lumbar movement or sustained postures
- Leg pain worsened by coughing, sneezing or straining, where present
- A disc herniation or stenosis on imaging that matches the clinical level
Not every radiculopathy has objective weakness or reflex change. Many people have radicular pain with a normal neurologic exam.
Deep gluteal syndrome: entrapment of the sciatic nerve itself
Deep gluteal syndrome is a non-discogenic sciatic nerve entrapment in the deep gluteal space, beneath the gluteus maximus. A 2020 systematic review of 14 studies and 853 patients found that diagnosis typically combined history, physical examination, imaging, response to injection and, in some studies, nerve-specific testing. Features that raise suspicion include:
- Buttock or posterior hip pain, often the most prominent symptom
- Pain with prolonged sitting; difficulty sitting for 30 minutes was a common feature in the review
- Posterior thigh symptoms, with or without symptoms further down the leg
- Tenderness and provocation in the deep gluteal space
- Positive seated piriformis-type or active piriformis tests where appropriate
- Neural symptoms without a convincing lumbar nerve-root pattern
- Supporting findings on pelvic MRI or MR neurography, or a response to a diagnostic injection
The piriformis is only one possible cause. Fibrous bands, the obturator internus and gemelli, quadratus femoris and ischiofemoral pathology, hamstring conditions, trauma and vascular structures have all been described.
How they usually compare
| Lumbar radiculopathy | Deep gluteal syndrome | |
|---|---|---|
| Site of irritation | Lumbar or sacral nerve root | Sciatic nerve in the deep gluteal space |
| Back pain | Often present, though leg pain may dominate | Less typical as the main complaint; buttock pain more prominent |
| Symptom distribution | More likely to follow one nerve-root pattern | More likely buttock and posterior thigh, with variable leg symptoms |
| Sitting | May aggravate | Prolonged sitting raises suspicion |
| Lumbar movement and loading | More likely to change symptoms | Less likely to reproduce the leg symptoms |
| Neurologic deficit | Supports a root problem when present in a root pattern | Less typical; does not exclude it |
| Deep-gluteal tenderness and provocation | Can occur | Supports the diagnosis |
| Most useful imaging | Lumbar MRI | Pelvic MRI or MR neurography |
No single row decides the diagnosis. The pattern across the whole exam is what matters.
The straight-leg raise is a neural test, not a disc test
The straight-leg raise tensions and moves the sciatic nerve and its roots along their whole course. A positive test therefore points toward a neural component, but it does not identify where along the nerve the problem sits. Ankle dorsiflexion at the end of the straight-leg raise adds tension to the nerve without moving the hip or spine, so if it increases symptoms it helps separate nerve sensitivity from hamstring tightness.
A restricted straight-leg raise that changes with ankle dorsiflexion can support a neural component, but it does not by itself localize the problem to the lumbar spine or deep gluteal space. The slump test works on similar principles. Localization comes from combining neurodynamic findings with the neurologic exam, lumbar testing and deep-gluteal examination.
Can both happen at the same time?
Yes. A person can have a disc herniation and deep gluteal entrapment, or degenerative changes on a lumbar MRI that are unrelated to their leg symptoms. Disc changes are common in people without pain, so imaging is interpreted alongside the exam rather than in place of it. When findings point in both directions, both are considered and treated in order of priority.
Other causes of buttock and posterior thigh pain
- Proximal hamstring tendinopathy or hamstring syndrome: pain at the sitting bone, often with sitting and running; the sciatic nerve lies close to the hamstring origin. See proximal hamstring tendinopathy vs. sciatic nerve pain.
- Ischiofemoral impingement: narrowing between the ischium and femur that can affect the quadratus femoris and nearby nerve.
- Sacroiliac joint and lumbar referred pain: buttock and thigh pain that is somatic rather than neural.
- Hip joint problems: usually groin-predominant, but sometimes buttock pain.
- Gluteal tendinopathy: lateral hip pain. See lateral hip pain and gluteal tendinopathy.
- Vascular claudication: buttock or leg pain with walking that settles with standing still.
When does sciatica need imaging?
Lumbar MRI is considered when lumbar radiculopathy or another nerve-root problem is suspected and the result would change management, and sooner when there is significant or progressive neurologic deficit. Pelvic MRI or MR neurography may help when deep gluteal entrapment is suspected or the diagnosis remains uncertain. Neither is needed for every patient, and a scan is always interpreted in the context of the exam.
Symptoms that need urgent medical care
New bowel or bladder dysfunction, saddle numbness, progressive weakness, severe rapidly progressive neurologic symptoms, major trauma, fever or systemic illness, and concern for cancer or infection need prompt medical assessment. Ordinary radiating leg pain on its own is not a red flag.
Does the distinction change treatment?
Yes. A lumbar root problem is managed as a lumbar presentation, which may include activity modification, graded loading, medication from a medical provider, injections or surgical referral when appropriate. Suspected deep gluteal entrapment shifts attention to the deep gluteal space: hip and gluteal loading, nerve-mobility work, manual treatment of restricted tissue, and in selected piriformis-type presentations, shockwave, which has randomized evidence reviewed in shockwave therapy for sciatica and deep gluteal syndrome. Whether fibrous tissue can tether the nerve is covered in can fibrous adhesion entrap the sciatic nerve?
How Novo evaluates sciatica
We take a detailed history, screen strength, reflexes and sensation, test lumbar movement and loading, perform neurodynamic testing, examine the deep gluteal space, hip and hamstring origin, and review previous imaging and treatment. The aim is to localize the problem before choosing a treatment. See how we approach sciatica and sciatic nerve entrapment and low back pain, or book a new patient exam.
References
- Kizaki K, Uchida S, Shanmugaraj A, et al. Deep gluteal syndrome is defined as a non-discogenic sciatic nerve disorder with entrapment in the deep gluteal space: a systematic review. Knee Surgery, Sports Traumatology, Arthroscopy. 2020;28(10):3354-3364. PMID 32246173. (link)
- Hernando MF, Cerezal L, Pérez-Carro L, et al. Deep gluteal syndrome: anatomy, imaging, and management of sciatic nerve entrapments in the subgluteal space. Skeletal Radiology. 2015;44(7):919-934. PMID 25739706. (link)
- Carro LP, Hernando MF, Cerezal L, et al. Deep gluteal space problems: piriformis syndrome, ischiofemoral impingement and sciatic nerve release. Muscles, Ligaments and Tendons Journal. 2016;6(3):384-396. PMID 28066745. (link)
- Park MS, Yoon SJ, Jung SY, Kim SH. Clinical results of endoscopic sciatic nerve decompression for deep gluteal syndrome: mean 2-year follow-up. BMC Musculoskeletal Disorders. 2016;17:218. PMID 27206482. (link)
