Sciatica: Causes, Differential Diagnosis and Treatment of Piriformis-Related Pain

Sciatica is not the name of a single disease; it is a clinical presentation describing pain, numbness and tingling along the sciatic nerve. Its most common cause is lumbar disc herniation. Among non-spinal causes, a leading one is piriformis syndrome, where the sciatic nerve is compressed within the piriformis muscle in the buttock. Often confused with disc-herniation pain, piriformis syndrome is treated with physiotherapy, a specific exercise programme and, additionally, an imaging-guided piriformis injection.

What Is Sciatica? Causes and Differential Diagnosis

Sciatica describes pain, numbness, tingling or weakness along the sciatic nerve’s course from the lower back into the leg; it is not a diagnosis in itself. In patients presenting with radiating leg pain, the following causes are considered:

• Lumbar Disc Herniation: The most common cause of sciatic pain; herniated disc tissue compresses and irritates the nerve root. Details: Lumbar Disc Herniation Treatment.
• Spinal Stenosis: Causes leg pain and exhaustion that increase with walking and decrease with leaning forward or sitting. Details: Spinal Stenosis Treatment.
• Piriformis Syndrome: A leading non-spinal cause; the sciatic nerve is compressed within this buttock muscle. It is discussed below.
• Other Causes: Hip joint problems, sacroiliac-joint-related pain and peripheral nerve entrapment are less common causes.

What Is Piriformis Syndrome?

Beyond lumbar osteoarthritis and disc herniation, piriformis syndrome is an important hidden cause of radiating leg pain. The sciatic nerve leaves the lower back and passes through or just beneath the piriformis muscle deep within the buttock before extending down the back of the leg. An awkward, unbalanced or sudden movement, or excessive strain/contraction of this muscle, usually causes the nerve to become trapped between its fibres. This clinical picture, known as piriformis syndrome, is triggered by nerve compression and is now also considered within the group of pain conditions arising deep in the buttock (deep gluteal syndrome).

How Is Piriformis Syndrome Diagnosed and Distinguished from Disc Herniation?

It presents with the following clinical features:

• Local Buttock Pain: Deep, intense, one-sided pain felt at a specific point in the buttock. The most common findings are buttock pain, tenderness over the prominence in the upper posterior buttock, and pain increasing with prolonged sitting [4].
• Radiating Leg Pain and Numbness: Pain may travel from the buttock into the thigh and down the back of the leg along the compressed sciatic nerve.
• Confusing Clinical Presentation: Because it radiates into the leg, this pain is often mistaken for lumbar disc herniation by patients and sometimes even physicians. The problem, however, lies directly in the buttock’s muscle anatomy, not in the lumbar discs.

Lumbar MRI must be obtained to rule out disc herniation. Diagnosis mainly rests on the clinical presentation and the absence of lumbar MRI findings that could explain the problem. Hip MRI may sometimes identify the compression site, but frequently shows no abnormality. There is no single standard test that definitively establishes piriformis syndrome; a proposed clinical assessment score from a series of 250 patients can aid diagnosis [6].

Combined Treatment for Piriformis Syndrome

1. First Stage (Basic Measures): In early cases, brief rest, targeted medication and clinical exercises to stretch the piriformis muscle give favourable results in some of our patients. In the 250-patient series, half (51%) improved with medication and rehabilitation [6].
2. Second Stage (Interventional Pain Treatment): For patients whose muscle spasm and pain persist despite conservative methods, we use piriformis injection [2, 3].

How Is a Piriformis Injection Performed?

It is an interventional method aimed at reducing mechanical and chemical pressure on the sciatic nerve.

Technique

It is performed in an operating theatre under advanced imaging guidance (fluoroscopy or ultrasound). Imaging clearly shows the piriformis muscle on screen, allowing a special combination of medications to be injected into the target muscle with millimetre precision.

Treatment Aim

The injected combination rapidly reduces swelling and inflammation irritating the nerve in that area. It also relaxes the contracted piriformis muscle, relieving pressure on the sciatic nerve.

Procedure and Patient Safety

• Duration and Anaesthesia: No extensive preparation is needed. The procedure uses local anaesthesia only, numbing the relevant area. The injection itself takes an average of 5–10 minutes.
• Discharge: After resting briefly in the clinic, our patients can walk home the same day.
• Risks: Serious complications are rare in experienced hands with imaging guidance. It is a targeted approach that spares patients a prolonged heavy medication burden.

What Is the Success Rate of Piriformis Injection?

Targeted injection is effective for buttock and leg pain caused by piriformis syndrome. Among patients with a positive diagnostic test (FAIR), 79% reported at least 50% pain reduction with injection and physiotherapy; average improvement was 71% [1]. A study in our country found that local anaesthetic injection into the piriformis significantly reduced pain [2]. The combination of local anaesthetic and cortisone was found most effective [3]. This ultrasound- or fluoroscopy-guided intervention relieves muscle spasm and pressure from the piriformis on the sciatic nerve; it has both therapeutic and diagnostic value in buttock pain confused with disc herniation [1, 2, 7]. By relieving spasm, the injection improves participation in physiotherapy [1].

What Are the Risks and Side Effects?

Ultrasound- or fluoroscopy-guided piriformis injection has a low complication rate. Outcomes are similar with both imaging methods; in each, the needle is advanced under visual guidance, allowing a controlled procedure [5]. The most common side effects are temporary fullness, tenderness or muscle aching at the injection site for a few days, which resolve on their own [2, 5]. Serious complications such as infection, bleeding and nerve injury are rare when the procedure is performed under sterile conditions with imaging guidance.

🩺 Physician’s Insight & Clinical Experience

“Many patients come to my clinic saying, ‘Doctor, my leg hurts terribly; my disc must have ruptured.’ After neurological examination and MRI, I often find no lumbar herniation and identify the piriformis muscle in the buttock as the cause. I first direct patients towards conservative treatments. When physiotherapy and exercise do not provide relief, I aim to support treatment by entering the muscle under imaging guidance and relieving the spasm with an injection. My clinical observation, however, is that injection alone cannot achieve complete success in this condition: the patient must follow an appropriate exercise programme.”

Frequently Asked Questions

Is Piriformis Syndrome the Same as Sciatica?

No. Sciatica describes pain and numbness along the sciatic nerve; piriformis syndrome is one of the leading non-spinal causes of this presentation. The most common cause of sciatic pain is lumbar disc herniation.

What Is the Success Rate of Piriformis Injection?

Of patients with a positive diagnostic test, 79% reported at least 50% pain reduction with injection plus physiotherapy [1]; studies in our country and abroad confirm effectiveness [2, 3].

Does Piriformis Injection Have Risks or Side Effects?

Yes, but they are low: the most common effect is temporary fullness or muscle aching at the injection site for a few days; serious complications are rare [2, 5].

Does Sciatic Nerve Pain Radiate into the Leg?

Yes. The sciatic nerve is the longest and thickest nerve in the body. It leaves the lower back, passes through the buttock and extends to the foot. When compressed by the piriformis, pain begins in the buttock and radiates as a pulling or electric sensation down the back of the thigh, behind the knee and sometimes to the ankle.

What Happens If Sciatic Nerve Compression Is Not Treated?

Pain persists, and chronic nerve pressure can lead to weakness and numbness in the leg muscles. New leg weakness or impaired urinary control should not be attributed solely to piriformis syndrome and must be assessed without delay.

Which Activities Should Patients Avoid, and Which Exercises Should They Do?

Avoid prolonged sitting on hard surfaces, carrying a wallet in the back pocket and strenuous uphill running. Piriformis stretches, drawing a crossed leg towards the chest, are a fundamental part of treatment.

What Helps Sciatica?

During an acute episode, brief rest, medication to reduce swelling and heat application can help. In the longer term, regular stretching and injections in selected patients are important.

Which Specialist Performs Piriformis Injections in Istanbul?

One of the physicians performing piriformis injections in Istanbul is M. Levent Deniz, MD, a specialist in brain, nerve and spine surgery.

How Much Does a Piriformis Syndrome Injection Cost?

As treatment costs vary according to the patient and hospital conditions, a definite fee can only be determined after examination and review of imaging.

References

1. Fishman LM, Dombi GW, Michaelsen C, et al. Piriformis syndrome: diagnosis, treatment, and outcome — a 10-year study. Arch Phys Med Rehabil. 2002;83(3):295-301. PMID: 11887107.
2. Misirlioglu TO, Akgun K, Palamar D, Erden MG, Erbilir T. Piriformis syndrome: comparison of the effectiveness of local anesthetic and corticosteroid injections: a double-blinded, randomized controlled study. Pain Physician. 2015;18(2):163-171. PMID: 25794202.
3. Hilal FM, Bashawyah A, Allam AE, et al. Efficacy of Botulinum Toxin, Local Anesthetics, and Corticosteroids in Patients With Piriformis Syndrome: A Systematic Review and Meta-analysis. Pain Physician. 2022;25(5):325-337. PMID: 35901473.
4. Hopayian K, Song F, Riera R, Sambandan S. The clinical features of the piriformis syndrome: a systematic review. Eur Spine J. 2010;19(12):2095-2109. PMID: 20596735.
5. Fowler IM, Tucker AA, Weimerskirch BP, Moran TJ, Mendez RJ. A randomized comparison of the efficacy of 2 techniques for piriformis muscle injection: ultrasound-guided versus nerve stimulator with fluoroscopic guidance. Reg Anesth Pain Med. 2014;39(2):126-132. PMID: 24509422.
6. Michel F, Decavel P, Toussirot E, et al. Piriformis muscle syndrome: diagnostic criteria and treatment of a monocentric series of 250 patients. Ann Phys Rehabil Med. 2013;56(5):371-383. PMID: 23684470.
7. Li S, Sun Y, Zhang Q, Zhang W, Qin X. Analysis of the Effectiveness of Injection-Based Minimally Invasive Treatment for Piriformis Syndrome: Clinical Outcomes and Anatomical Correlates. Curr Pain Headache Rep. 2026;30(1):84. PMID: 42406261.

• 👨‍⚕️ Author and medical reviewer of this content: M. Levent Deniz, MD – Brain, Nerve and Spine Surgeon
• ⚠️ Medical Disclaimer: This page is for information only; consult your doctor for diagnosis and treatment.