June 30, 2026
At NYDNRehab in New York City, we see it every week: patients who have been told they have sciatica, treated for sciatica, and yet continue to suffer because the real source of their pain was never correctly identified. Sciatica is one of the most overdiagnosed and mismanaged conditions in musculoskeletal medicine, and the consequences of misdiagnosis can mean months or even years of unnecessary pain, failed treatments, and avoidable procedures.
Understanding the difference between true sciatica and its many imposters is not just clinically important, it is life-changing for patients who deserve accurate answers and effective care.
True sciatica refers to pain, numbness, tingling, or weakness from compression or irritation of the roots of the sciatic nerve, usually at the L4, L5, or S1 levels of the lumbar spine. The sciatic nerve is the longest and widest nerve in the human body, running from the lower back to the buttocks and down each leg to the foot.
Classic symptoms include sharp, stabbing, or burning pain that radiates from the lower back to the buttock and down the back of the leg, often following a dermatomal pattern.
Numbness, tingling, and muscle weakness may accompany the pain. Though an identical symptom picture can come from completely different anatomical sources that have nothing to do with the lumbar spine. These are sciatica impostors, and they are much more common than most clinicians recognize.
One of the most important, and least discussed, reasons why sciatica is so often misdiagnosed is the over-reliance on lumbar MRI as a definitive diagnostic tool.
MRI is an extraordinary technology, truly essential when it is necessary to exclude serious pathology such as a tumor, a fracture, or severe stenosis. Yet MRI has a critical limitation that is rarely communicated to patients: a positive MRI result does not automatically mean that the finding is the cause of your pain.
Research has consistently shown that disc bulges, herniated discs, and degenerative changes are extremely common in pain-free adults. A landmark study published in the New England Journal of Medicine found that among people without any back pain, about half had a disc bulge visible on MRI and more than a quarter had a disc protrusion. Finding a disc bulge on MRI in a patient with leg pain does not confirm that the disc is the source of the pain; it may simply be an incidental finding coexisting with a completely different pain generator.
The problem is compounded by the fact that the extra-spinal structures most often responsible for sciatica imposters, the piriformis muscle, the deep gluteal space, and the SI joint, are not visualized on standard lumbar MRI. These structures require different imaging protocols, different physical examination techniques, and an entirely different diagnostic mindset. At NYDNRehab, we treat the patient, not the MRI report.
The piriformis muscle lies deep in the buttock, directly above the sciatic nerve. When it becomes tight, inflamed, or develops trigger points, it can compress or irritate the sciatic nerve, producing buttock pain and radiating leg symptoms that are clinically hard to distinguish from a lumbar disc herniation.
A common scenario: a competitive runner develops progressive pain in the buttock and back of the thigh that gets worse during long runs. The lumbar MRI is completely normal. They are told the pain is muscular and given generic stretching exercises. Months later they arrive at NYDNRehab, where a high-resolution ultrasound identifies piriformis hypertrophy with dynamic compression of the sciatic nerve, invisible on the prior imaging. Importantly, piriformis syndrome can cause numbness and tingling in addition to pain, further reinforcing an incorrect spinal diagnosis.
One of the most common but overlooked causes of buttock and leg pain is the sacroiliac (SI) joint. Dysfunction of the SI joint can radiate pain into the buttock, groin, and posterior thigh, closely resembling sciatica. SI joint pain is thought to account for 15 to 30% of chronic low back pain presentations and is commonly unrecognized, often triggered by rising from a chair, rolling over in bed, or climbing stairs.
Deep buttock pain, which may radiate down the posterior thigh, is a typical symptom of high hamstring tendinopathy at the ischial tuberosity which leads many clinicians to prescribe a lumbar disc diagnosis. The hamstring is close to the sciatic nerve and can further irritate the nerve if it becomes inflamed.
Labral tears, femoroacetabular impingement (FAI), and hip osteoarthritis can refer pain into the groin, lateral thigh, and buttock. A hip condition should always be considered when groin pain accompanies apparent sciatic symptoms.
Leg pain that occurs during walking may be a manifestation of peripheral arterial disease and is similar to neurogenic claudication. A clinical scenario: A patient in his 60’s with hypertension complains of cramping in both legs after walking for two blocks, which is improved by rest in any position, but worsened by sitting or spinal flexion. Lumbar MRI is done and the results are slightly narrowed. Ankle-brachial index test reveals significant peripheral arterial disease – the true diagnosis.
These are not nerve compression syndromes, but muscular trigger points in the gluteus medius, gluteus minimus and piriformis muscles that create a pattern of referred pain with a distribution that is very similar to that of the sciatic nerve, which is commonly overlooked in imaging assessments.
Deep Gluteal Syndrome (DGS) represents one of the most significant advances in understanding sciatic-type extraspinal pain, yet it remains largely underdiagnosed. At NYDNRehab, DGS evaluation is an essential part of any assessment involving buttock pain and radiating leg symptoms.
DGS describes entrapment or irritation of the sciatic nerve in the deep gluteal space, the anatomical region behind the hip joint, bounded by the gluteal muscles, short external rotators, and ischium. Unlike lumbar sciatica originating at the spinal level, DGS involves compression or fixation of the sciatic nerve as it travels through this complex corridor.
Structures capable of trapping the sciatic nerve in the deep gluteal space include:
Static entrapment occurs when a structural abnormality compresses the sciatic nerve regardless of its position. Dynamic entrapment only occurs during specific movements: the nerve may be completely free at rest but becomes compressed during hip flexion or internal rotation.
Dynamic entrapment cannot be detected on standard static MRI. A patient can have a perfectly normal MRI yet still have significant functional nerve compression that only appears during movement. A clinical scenario: a 38-year-old cyclist presents with six months of left buttock pain and posterior thigh numbness. The lumbar MRI shows a small L4-5 disc bulge. Two specialists recommend lumbar physiotherapy without improvement. At NYDNRehab, dynamic ultrasound reveals compression of the sciatic nerve in the deep gluteal space during hip flexion, absent at rest and invisible on MRI. The disc bulge was incidental. The actual diagnosis was deep gluteal syndrome
Conventional MRI provides no information about nerve behavior during movement. MR neurography improves sensitivity to peripheral nerve signal changes, and high-resolution diagnostic ultrasound provides real-time dynamic assessment, allowing direct observation of nerve compression during active hip movement. At NYDNRehab, dynamic ultrasound is essential for identifying DGS and entrapment syndromes invisible on standard imaging.
“Your MRI looks OK” is perhaps the most frustrating phrase a pain patient can hear. At NYDNRehab, we are unequivocal: a normal MRI does not mean normal. This means that the source of the pain is not visible on this particular imaging study.
When a patient presents with sciatica-like symptoms and a normal lumbar MRI, the correct answer is to expand the diagnostic investigation to include extraspinal structures that standard MRI cannot evaluate, precisely what we do at NYDNRehab using high-resolution diagnostic ultrasound, focused physical examination, and ultrasound-guided diagnostic injections.
An often overlooked dimension of persistent sciatic-type pain is the role of the fascial system in sciatic nerve mobility. As the sciatic nerve travels from the lumbar spine through the deep gluteal space and down the leg, it should slide and elongate freely through the fascial tunnels and interfascial planes. Fascial restrictions from chronic postural stress, repetitive strain, post-surgical fibrosis, or trauma can reduce the nerve’s ability to glide freely, a process sometimes described as fascial densification that mechanically tethers neural structures.
Reduced nerve gliding can generate pain during movements that require nerve elongation, create symptoms mimicking nerve root compression despite normal imaging, and persist after surgery if fascial adhesions are not addressed. Post-surgical and post-traumatic patients are particularly vulnerable: scar tissue following lumbar surgery, hip replacement, or hamstring repair can create persistent sciatic symptoms often incorrectly attributed to surgical failure. Evidence from neurodynamic research supports neural mobilization techniques as an effective approach to restore nerve gliding capacity and reduce fascial-mediated symptoms.
Yes. Extra-spinal causes such as piriformis syndrome and deep gluteal syndrome frequently produce buttock and leg pain without any back pain – a main reason they are misdiagnosed as lumbar sciatica.
Standard lumbar MRI cannot visualize the deep gluteal space, dynamic nerve compression, fascial restrictions, or sacroiliac joint dysfunction. A normal MRI means that the source of the pain is not visible in this study even if no problem exists.
Yes. Post-surgical or post-traumatic scar tissue can tether the sciatic nerve in its fascial course, generating pain and neurological symptoms identical to structural nerve compression.
Deep gluteal syndrome is sciatic nerve entrapment occurring in the deep gluteal space, the region posterior to the hip joint. This is a significant cause of buttock and leg pain that regularly goes unnoticed on standard imaging.
Yes. Numbness, tingling and weakness in the posterior thigh and leg can be caused by compression of the sciatic nerve by the piriformis, and are identical with symptoms of lumbar radiculopathy.
Diagnostic ultrasound can directly visualize the sciatic nerve and evaluate the compression during the movement; this is a unique capability of diagnostic ultrasound that is not possible by MRI, which can only assess static compression.
No. Most patients will benefit from conservative treatment such as physiotherapy, specific injections and neurodynamic rehabilitation. Surgery is usually reserved for progressive neurological deficits or overall failure of conservative management.
Yes. When properly targeted to the correct diagnosis, physical therapy including neurodynamic techniques, hip muscle retraining and fascia mobilization can be very effective against both true sciatica and imposter sciatica.
High-resolution dynamic ultrasound, detailed clinical history and specific tests in physical examination are needed for the diagnosis of DGS. The MRI is not enough. At NYDNRehab, we use dynamic ultrasound assessment as the cornerstone of DGS diagnosis.
Evaluation by a specialist is strongly recommended if you have been having pain in your legs or buttocks for more than 6 weeks, if you have a normal MRI but still have symptoms, if you have not responded to conservative treatment or if you have any of the alarm symptoms listed above.
If you’ve been diagnosed with sciatica or your imaging tests are normal but you still have pain, the team at NYDNRehab has the latest diagnostic and treatment options in New York.
Our approach combines:
We specialize in diagnosing and treating other conditions that other clinics fail to address such as deep gluteal syndrome, piriformis syndrome, SI joint dysfunction and fascial-mediated nerve entrapment. Our patients receive an accurate diagnosis, a clear explanation of their condition, and a treatment plan built around their specific anatomy and goals. precise diagnosis, a clear explanation of their condition, and a treatment plan built around their specific anatomy and goals.
Don’t waste another month with the wrong diagnosis. Call NYDNRehab today to schedule a thorough evaluation and receive the answers you are looking for.
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Our location: 11 West 25th Street 5th floor, New York, NY 10010
Dr. Lev Kalika is a world-recognized expert in musculoskeletal medicine. with 20+ years of clinical experience in diagnostic musculoskeletal ultrasonography, rehabilitative sports medicine and conservative orthopedics. In addition to operating his clinical practice in Manhattan, he regularly publishes peer-reviewed research on ultrasound-guided therapies and procedures. He serves as a peer reviewer for Springer Nature.
Dr. Kalika is an esteemed member of multiple professional organizations, including:
Below is a prime example of how ultrasound can take the guesswork out of diagnosis.
A bad physical therapy experience is one of the primary causes of unnecessary surgery
In this instance, an athlete was originally diagnosed with minor quadriceps muscle strain and was treated for four weeks, with unsatisfactory results. When he came to our clinic, the muscle was not healing, and the patients’ muscle tissue had already begun to atrophy.
Upon examination using MSUS, we discovered that he had a full muscle thickness tear that had been overlooked by his previous provider. To mitigate damage and promote healing, surgery should have been performed immediately after the injury occurred. Because of misdiagnosis and inappropriate treatment, the patient now has permanent damage that cannot be corrected.
The most important advantage of Ultrasound over MRI imaging is its ability to zero in on the symptomatic region and obtain imaging, with active participation and feedback from the patient. Using dynamic MSUS, we can see what happens when patients contract their muscles, something that cannot be done with MRI. From a diagnostic perspective, this interaction is invaluable.
Dynamic ultrasonography examination demonstrating
the full thickness tear and already occurring muscle atrophy
due to misdiagnosis and not referring the patient
to proper diagnostic workup
Demonstration of how very small muscle defect is made and revealed
to be a complete tear with muscle contraction
under diagnostic sonography (not possible with MRI)
Complete tear of rectus femoris
with large hematoma (blood)
Separation of muscle ends due to tear elicited
on dynamic sonography examination
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