Overview

Piriformis syndrome can be a real pain in the well and buttocks. It occurs when your piriformis muscle compresses your sciatic nerve, causing the nerve to be entrapped. This entrapment causes pain, numbness, or tingling in areas including your buttocks, hip, and upper leg. Understanding the roles of the piriformis muscle and the sciatic nerve is crucial in grasping the mechanisms behind this syndrome.

The piriformis muscle is a flat, pear-shaped muscle located in the gluteal area (the buttocks). It connects your sacrum (the triangular bone at the base of your spine) to the top of the femur (thigh bone). This muscle helps your hip to do external rotation and flexion. It also stabilises the hip joint during various activities such as sitting, walking, or running. 

The sciatic nerve is responsible for motor function (movement) and sensory function (sensation) in your lower limbs. It runs from the lower spine (lumbar and sacral region) to the back of your leg. This nerve facilitates activities such as walking, running, and standing.

The diagnosis of piriformis syndrome is quite complicated, as many cases of low back and buttock pain share similar clinical characteristics. Treatment modalities include conservative and invasive approaches that vary from person to person based on their condition.^1,2

Diagnosis

Clinical assessment

If you have piriformis syndrome, the symptoms that you may feel include:

• Pain, numbness, burning, or shooting sensation in your buttock, hip area, and upper leg area
• Worsened pain when doing hip movements, such as walking and running or after sitting for a long time
• The pain can radiate to the back of the leg or sometimes to the lower leg

During your visit, your healthcare provider will also conduct a physical assessment to diagnose piriformis syndrome. This may involve performing stretching manoeuvres to irritate the piriformis muscles and give manual pressure around your sciatic nerve that may help provoke the symptoms. 

The stretching test includes:

• Freiberg manoeuvre: The doctor forcefully rotates your thigh inward while it is straightened out (extended leg).
• Pace manoeuvre: Resisting abduction and external rotation of the hip while in a flexed or sitting position.
• Beatty manoeuvre: You will lie on your side and hold a flexed knee several inches above the table.
• FAIR test: This manoeuvre combines different movements of the hip joint — flexion (bending the hip), adduction (moving the hip inward toward the midline of the body), and internal rotation (rotating the hip inward). When you flex your hip, the piriformis muscle will stretch and may compress the sciatic nerve.¹

Imaging techniques

Even though the diagnosis is primarily based on clinical evaluation, some imaging modalities such as magnetic resonance imaging (MRI) and computed tomography (CT) can be useful to rule out other conditions. 

Another modality that can also be used is electrodiagnosis testing which aids in distinguishing piriformis syndrome from other disorders. In piriformis syndrome, weakness and atrophy typically affect only the distal part of the muscle. In contrast, nerve impingement may manifest with atrophy in both the distal and proximal regions of the piriformis, along with abnormalities detected in electromyography (EMG) and muscle weakness.^1,3

Conditions that commonly need to be excluded are:^2,4

• Sciatica 
• Hamstring injury
• Lumbosacral disc injuries
• Lumbosacral facet syndrome
• Lumbosacral radiculopathy
• Lumbosacral spine sprain
• Lumbosacral spondylolisthesis
• Lumbosacral spondylolysis
• Sacroiliac joint injury/dysfunction

Treatment options

Conservative management

The main goal of conservative treatments is to reduce pain and inflammation while improving your hip’s flexibility and strength. Patients who have no significant alarm symptoms can begin with this treatment. Some of the approaches are:

• Rest. As the pain in this syndrome can be aggravated by movement and activities such as walking, climbing stairs, and running, try to rest to avoid the pain getting worse. The rest should be short-term, no longer than 48 hours to relieve symptoms.⁵
• Pain relief. Using over-the-counter medications such as Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) like ibuprofen can help you reduce the pain and inflammation caused by the syndrome. However, you need to remember that if you use these medications for a long time, it can cause stomach ulcers. Remember to always consult with your doctor before taking any medications. Additionally, your doctor may prescribe neuropathic agents such as gabapentin and pregabalin if you do not respond adequately to NSAIDs.^1,5
• Physical therapy. The recommended physical therapy involves exercises that focus on external rotation, hip flexion, and adduction. By stretching these muscles, you can alleviate nerve compression and relax tight muscles. These stretches can be performed while standing or lying down. The objective is to alleviate symptoms by loosening tight muscles, improving range of motion, and strengthening muscles. Another technique called counterstrain has also shown success in relieving pain associated with piriformis spasm.^1,3

Medication injections

• Lidocaine injection. Lidocaine (a type of local anaesthetic drug) will be injected into your piriformis sheath. This treatment has been shown to be beneficial in reducing pain and improving patient functionality.
• Steroid injection. Gives temporary pain relief so that you can engage in physical therapy. However, this treatment does not target the underlying cause and may need to be repeated.
• Botulinum toxin injection. Botulinum toxin type A (BoNT-A) stops the release of neurotransmitters from nerve cells in the body by cutting specific proteins called SNARE, which are needed for the release of these chemicals. This action helps reduce muscle spasms and pain. Like other injections, it needs to be performed using ultrasound guidance due to the small size and deep location of the piriformis and its relationship to surrounding key neurovascular structures. Other options for injecting the piriformis muscle include using guidance with CT, MRI, or fluoroscopy. Due to the short duration of symptom relief, repeat injections may be necessary.^1,5

Surgery

Surgical intervention is typically a last resort for patients with piriformis syndrome. It is only will be considered if all other conservative and non-invasive approaches have failed. Surgical methods that are used to treat piriformis syndrome include open or endoscopic sciatic nerve decompression. This minimally invasive technique has been shown to be an effective treatment. During the surgery, the surgeon will release or remove a portion of the piriformis muscle to relieve the pressed sciatic nerve. As with any surgery, there are potential risks and complications involved, so it is recommended that you discuss the risks and benefits of these treatment options with your healthcare provider.^1,5,6

FAQs

What is the best treatment for piriformis syndrome?

The efficacy of treatments varies, with each tailored to individual patient needs. Conservative management is typically the initial approach, followed by minimally invasive procedures or surgery if necessary. Below are the available treatment options:⁵

• NSAIDs for symptoms relieve
• Physical therapy
• Steroid injection
• Botulinum toxin injections
• Surgery 

What triggers piriformis syndrome? 

Compression of sciatic nerve through or around your piriformis muscle. This compression may be caused by:^1,7

• Trauma in your buttock area or the hip.
• Activities that require sitting for prolonged periods such as office workers, taxi drivers, and bicycle riders.
• Hypertrophy (increased muscle mass) of the piriformis muscle is usually seen in athletes.
• Anatomic abnormalities.

How do you diagnose piriformis syndrome?

The diagnosis will be based on the patient's medical history (symptoms and signs), a physical examination, and if needed, other modalities such as imaging (X-rays, MRI) to see structural abnormalities or electromyography (EMG) to see electrical activity response to the nerve stimulation.

Can piriformis syndrome be seen on MRI?

MRI is a useful component in diagnosing piriformis syndrome. It can help differentiate this condition from other causes with similar symptoms. MRI can visualise the characteristic structural changes in the piriformis muscle and its relationship with the sciatic nerve.⁸

What is piriformis syndrome commonly misdiagnosed as?

There are many conditions that share the same clinical characteristics with piriformis syndrome, one of the most common is sciatica. 

Sciatica happens as a result of compression or irritation of the sciatic muscle due to spinal issues such as a herniated disc or spinal stenosis. Both the sciatica and piriformis syndrome patients will feel the symptoms of pain in the buttocks and the radiation pain to the leg.¹

Summary 

Piriformis syndrome occurs when the piriformis muscle, deep in the buttock, compresses the sciatic nerve, leading to nerve irritation and symptoms such as pain and numbness that can radiate down the leg. Diagnosis typically involves history-taking, physical examination, and imaging or electromyography if needed. Treatment options include:

• Conservative management, including rest, modifying activities, pain relief measures, and physical therapy
• Lidocaine injection, a local anaesthetic, to provide temporary relief from pain
• Steroid injection, to reduce inflammation and alleviate symptoms
• Botulinum toxin injection, to relax the piriformis muscle and reduce nerve compression
• Surgery: In severe cases or when conservative measures fail, surgical intervention may be considered to release pressure on the sciatic nerve.