Piriformis syndrome is one of the most misunderstood and misdiagnosed pathologies in the physical therapy field – at least amongst the young physios.[i]
That’s because of the large differential diagnosis and overlapping symptoms with sciatica and other clinical conditions that affect the low back and hip region.
The prevalence of piriformis syndrome amongst patients with low back pain [LBP] or buttocks pain is 6.25%. Hence it’s not a common disorder but Physical Therapists [PTs] should still learn to understand this condition so that they can diagnose it properly and improve treatment outcomes.
In this article, we’ll cover the causes, diagnostics procedure, treatment method and the expected recovery window of piriformis syndrome based on the current best evidence.
At the end of this post, we trust that you’ll be able to form a differential diagnosis of sciatica with confidence. And prescribe the correct physical therapy treatment regimen to your piriformis syndrome patients.
Let’s begin!
Overview of The Piriformis Syndrome
Piriformis syndrome is a neuromuscular condition in which the Piriformis muscle compresses the sciatic nerve. This is most common in the sciatic notch at the level of the ischial tuberosity.
The patients suffer from pain, tingling and numbness in their lower back, buttock or thigh region. And symptoms may also radiate down the back of the leg.
The piriformis muscle extends between the sacrum and the greater trochanter of the femur. It functions as the external rotator of the leg, stabilizer of your hip and also helps you in walking and balancing while shifting weight between the two feet.
In more than 80% of the population, the sciatic nerve passes underneath the piriformis muscle before exiting the pelvic. But in 10-15% of the population, this nerve actually passes through the piriformis muscle hence being vulnerable to compression due to a spasm of the muscle.[ii]
In more than 80% of the population, the sciatic nerve passes underneath the piriformis muscle before exiting the pelvic. But in 10-15% of the population, this nerve actually passes through the piriformis muscle hence being vulnerable to compression due to a spasm of the muscle.
Some people are more likely to get piriformis syndrome than others. These high-risk populations include people who sit for a long time particularly on a hard surface such as office workers, car or truck drivers and long-distance bicycle riders.
Also, athletes who perform excessive twisting motions at the hip such as tennis players are prone to developing piriformis syndrome because their piriformis may overwork to compensate for a tired gluteus medius muscle.
What Causes Piriformis Syndrome?
Tightness of the piriformis muscle or inherent anomalies of the sciatic nerve are the primary causes of the syndrome. But these aren’t the leading causes. In fact, research shows that fewer than 15% of the total piriformis syndrome patients have these primary causes.
The current evidence suggests that the piriformis syndrome is mostly the result of secondary causes. These include trauma to the buttocks, irritation, swelling or spasm of the piriformis muscle, lumbar and SIJ pathologies, excessive external compression at the hip and altered biomechanics of the lower limb.[iii]
The current evidence suggests that the piriformis syndrome is mostly the result trauma to the buttocks, irritation, swelling or spasm of the piriformis muscle, lumbar and SIJ pathologies, excessive external compression at the hip and altered biomechanics of the lower limb.
Irritation of the piriformis muscle may cause it to tighten. This irritation may come from sitting too long, placing a big wallet in your back pocket or wearing tight clothing that compresses the pelvis region.
Other causes of piriformis syndrome include shortened piriformis muscle, macro trauma due to surgery or accidents and microtrauma due to overuse such as hiking or walking.
Diagnosing the Piriformis Syndrome
Piriformis syndrome is diagnosed by exclusion which means that you can make the final diagnosis after excluding all other possible causes. Diagnosis of this disorder is so challenging because the symptoms overlap with intra-spinal sciatica and other hip related neural conditions.
Piriformis syndrome is diagnosed by exclusion which means that you can make the final diagnosis after excluding all other possible causes.
Symptoms of piriformis syndrome vary a lot between patients. These patients not only come in with different complaints but also respond differently to the diagnostics tests, which further complicates the diagnosis for novice physical therapists.
1. Symptoms of Piriformis Syndrome
According to an updated systematic review published in 2017, here’s what your piriformis syndrome patients will likely present with at the clinic:
- Regional or radiating buttock pain
- Sitting aggravates the pain, especially on hard surfaces.
- Tenderness at the greater sciatic notch
- Pain on movements that increase piriformis muscle tension.
Other accompanying symptoms of the piriformis syndrome may be a burning sensation on the lateral aspect of the ipsilateral hip and upper thigh. Some patients complain that their pain increases when walking while others in the chronic stage of piriformis syndrome find pain relief in walking.
The accompanying symptom of the piriformis syndrome may be a burning sensation on the lateral aspect of the ipsilateral hip and upper thigh.
This inconsistency in the clinical presentation of piriformis syndrome patients is a major reason why this condition is repeatedly misdiagnosed and mistreated.
2. Physiotherapy Special Tests for Piriformis Syndrome
There is no definitive special test for piriformis syndrome but the combination of the following tests is used by physical therapists for establishing the diagnosis:
1. FAIR Test
This is the most widely used test Physical Therapists use to diagnose piriformis syndrome.
It’s the best test so far because it has a sensitivity of 0.881 and a specificity of 0.823. And its reliability has been shown in the study by Hal D. Martin et al. The patients who have a positive FAIR test on initial assessment also respond well to the current physical therapy treatment regimens for piriformis syndrome, which makes it an accurate test according to the working definition of the piriformis syndrome.
2. Pace Sign
This involves resisted abduction and external rotation of the thigh with the patient in a sitting position. Pace sign is positive in 46.5% of patients with piriformis syndrome.
3. Freiberg Test
Here, the physical therapist tries to stretch the piriformis muscle by passively internally rotating the hip with the patient in the supine position.
That places pressure on the sciatic nerve and elicits pain in the case of piriformis syndrome. A recent study found that the Freiberg test was positive in 56.2% of the patients.
4. Beatty Test
Here, the physical therapist abducts and elevates the symptomatic leg while the patient is side-lying on the asymptomatic side. The knee on the painful side is flexed. This produces pain in the buttock region for piriformis syndrome patients.
Creating a Differential Diagnosis For Piriformis Syndrome
The hallmark signs of piriformis syndrome that we’ve covered above match the ones we see in sciatica due to lumbar herniated disk, spinal stenosis or pelvic muscular spasms.
So here are some tips that can help you eliminate other causes of sciatica and confirm the piriformis syndrome diagnosis of your patient:
- Piriformis syndrome is not accompanied by a loss of deep tendon reflexes or myotomal weakness. But lumbar stenosis or disk herniation may result in reflex changes.
- A positive SLR test indicates lumbar nerve root pathology with a sensitivity of 0.15 and specificity of 0.95. You can add this to the list of special tests to confirm or refute a piriformis syndrome diagnosis.
- Radiographs can help eliminate certain causes of sciatica. You can use MRI to rule out lumbar disk herniation. And CT or X-ray to rule out the hip and lumbar spine as causes.[iv]
Management of Piriformis Syndrome in Acute and Chronic Stage – Physiotherapy Treatments
Treatment for piriformis syndrome mainly revolves around stretching of the tight muscles and modification of ADLs to prevent future entrapments.
Massage therapy to relax the spasm of the muscle is also practiced by some physical therapists.[v]
Patients usually do not report excessive pain during the acute stage of the disorder. So the treatment should be according to the subjective and objective findings.
You can begin by prescribing cryotherapy to decrease inflammation, pain-free stretching to release the tight piriformis muscle and soft tissues elongations if tolerated.
You can begin by prescribing cryotherapy to decrease inflammation, pain-free stretching to release the tight piriformis muscle and soft tissues elongations if tolerated.
The common stretches for piriformis syndrome include
- Chair Stretch: While sitting on a chair, place the ankle of the symptomatic leg on the opposite knee and bend forward at the hips to feel a stretch in the piriformis muscle.
- Lying stretch: while laying on your back, place the ankle of the symptomatic leg on the opposite knee and pull the asymptomatic leg towards your chest.
- Sit cross-legged on the floor and put the soles of the feet together. Press down on your knees as well if it’s comfortable.
Hip muscle strengthening and movement reeducation may be the main goals for rehab of chronic piriformis syndrome.
This is especially useful for patients who demonstrate a gait pattern with excessive hip adduction and internal rotation. The case study Jason C. Tony et al. showed great results of strengthening and education regimen in treating piriformis syndrome.[vi]
The prognosis for most patients is excellent if you can make the diagnosis in the acute stage and follow it up with appropriate physical therapy treatment.[vii]
In Summary
These days, the term deep gluteal syndrome [DGS] is preferred over piriformis syndrome to describe non-disk related sciatica. But in the case of the DGS, the structures trapping and compressing the sciatic nerve can be the gluteal or hamstring muscles, blood vessels or tight fascia.[viii]
To sum it up, piriformis syndrome is a disorder where the sciatic nerve is compressed causing pain in the buttocks and low back. Your prescribed treatments should match the objective and subjective findings and should be targeted at resolving the causative factors.
The usual treatment regimens include stretching, gait training, movement reeducation and piriformis strengthening in patients with an abductor weakness.
[i] https://www.sciencedirect.com/science/article/abs/pii/S106018720400067X
[ii] https://www.sciencedirect.com/topics/neuroscience/piriformis-muscle
[iii] https://www.openaccessjournals.com/articles/piriformis-syndrome-with-red-flag-signs-12871.html#2
[iv] https://link.springer.com/article/10.1007%2Fs12630-013-0009-5
[v] https://www.spine-health.com/blog/2-little-known-treatments-piriformis-syndrome
[vi] https://www.jospt.org/doi/full/10.2519/jospt.2010.3108
[vii] https://europepmc.org/article/NBK/nbk448172
[viii] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6774708/