Regenerative Medicine

Regenerative Therapy Offers A Safe Alternative to Piriformis Injections

By Last updated on April 5, 2020 Last updated on April 5, 2020 No Comments


The piriformis is a muscle in the hip region which can become a source of pain for some individuals.

As the underlying causes become worse and the issue is aggravated, pain in the piriformis can become debilitating. Doctors will often recommend conventional treatment options which may be ineffective depending on the severity of pain.

Acute piriformis pain may require alternative treatments.

Though steroid injections are often the most popular of these alternative treatment methods, they often have grave consequences. Regenerative therapy offers a solution to not only the pain experienced by an individual with piriformis complications, but the underlying causes of that pain as well.

Anatomy of Piriformis

The piriformis is a small muscle located deep within the buttocks region. It is one of six muscles located behind the gluteus maximus (major outer muscle of the buttocks) which are known as the lateral rotator group. This group of muscles is responsible for rotating the femur in the hip joint. An individual can feel this muscle if they stand on a single leg and twist their body to one side.

The piriformis, along with the other five muscles in the lateral rotator group, originates in the hip bone and attaches to the upper portion of the femur. Specifically, the piriformis originates from the sacrum, the portion of the spine in the gluteal region, and exits the pelvis through a small hole known as the greater sciatic foramen to connect to the upper portion of the femur.

The muscle fills the upper portion of the hole in the pelvis and inserts into the femur by a rounded tendon, often blending with other tendons in the region.

The piriformis is innervated by the sacral plexus. The sacral plexus is a branching network of intersecting nerves which provides motor and sensory nerves throughout the posterior thigh. Along with the host of disorders and issues which may arise in the piriformis itself, the sacral plexus may also become a source of pain due to trauma, nerve compression, vascular disease, or infection.

The piriformis serves an important role in the lower body as it helps to stabilize the hip joint as well as lifts and rotates the thigh away from the body. In turn, an individual is able to walk, shift their weight from one leg to the other, and maintain balance. Injury to this vital muscle can cause instability and may be a source of constant pain if left unchecked.

Types of Piriformis Injuries

The piriformis is a common source of pain in the buttocks and posterior leg. Pain in the piriformis can begin spontaneously or after an injury. When the piriformis becomes damaged and this damage is aggravated, the muscle goes into spasms. These spasms squeeze and irritate the nerves of the sacral plexus and create pain throughout the piriformis.

It is estimated that at least 6% of patients who are diagnosed with lower back pain are actually experiencing some type of piriformis issue. Delay is diagnosing piriformis pain can lead to untreatable damage to the nerves within it. Compensatory changes to the biomechanics in the hip and thigh due to piriformis injury can lead to pain, paresthesia, hyperesthesia, and muscle weakness.

Some common causes of piriformis pain or injury are:

  • Inflammation
    • Jobs which require constant sitting and standing, especially with extra load on the body, may irritate the piriformis and cause the muscle to “puff up”, compressing the nerves within.
  • Trauma
    • Blunt trauma to the buttocks from a sports injury, fall, or other accidents, can cause microtears in the piriformis and lead to undue stress to the nerves within.

Other, less common, inciting events for piriformis pain are:

  • Hematoma
  • Scar formation
  • Cysts
  • Tumors

Whatever event led to piriformis pain, the mechanics are all the same. Once the piriformis is injured in any way, the nerves within the piriformis become aggravated or compressed and cause an individual to feel painful spasms in the buttocks region.

Signs and Symptoms of Piriformis Injury

Several signs and symptoms can help an individual conclude whether or not there may be damage to the piriformis. Some of the most common symptoms of piriformis injury are:

  • Pain with sitting, standing, or lying longer than 15 to 20 minutes
  • Pain improves with mobilization and worsens with no movement
  • Pain when rising from a seated or squatting position
  • Change of position does not relieve pain completely
  • Difficulty walking or maintaining balance
  • Numbness in the foot
  • Headache
  • Neck pain
  • Abdominal, pelvic, and inguinal pain
  • Pain with bowel movements

Beyond these symptoms an individual can also watch out for signs such as the following:

  • Tenderness over the piriformis muscle
  • Palpable mass in the buttock
  • Traction of affected limb provides moderate relief of pain
  • Asymmetrical weakness in the affected limb
  • Limited range of motion in the lower extremities

Though signs and symptoms vary from person to person, if an individual is experiencing any of the above, there may be a deeper issue relating to the piriformis muscle which will require doctor intervention. Due to the location of the piriformis, oftentimes, steroid injections are the only solution.

The most common treatment method for piriformis injury is steroid injections, though recently, advancements in regenerative medicine have begun to gain traction in this arena.

History of Piriformis Injections

The application of steroids to treat certain types of pain was first discovered in 1929 by a team of chemists working at the Mayo clinic. The team discovered that injecting certain steroids could give short-term pain relief and reduce swelling from inflammation of the joints, tendons, or bursa found throughout the body. Since their discovery, steroid injections have been used to treat a number of ailments and have been administered intravenously, orally, and intra-articularly (into a joint), or transdermally (using patches which lay directly on the skin).

Composition and Mechanics of Piriformis Injections

There are a variety of steroids which can be used to treat different conditions, but issues with soft tissues such as the piriformis typically involve the use of corticosteroids specifically. Corticosteroids are synthetic drugs which resemble cortisol, a hormone which the body naturally produces. Steroid injections work by suppressing the immune system, thus reducing inflammation and attendant pain and swelling at the site of injection. Risks exist, in particular in the long-term use of steroids.

The body’s natural response to injury is to create a sort of shelter in that area. By pushing fluid to the site of an injury, the body tries to protect that area from further trauma. Though swelling is intended to defend the body, too much of it can actually cause severe pain. This is the case in piriformis injuries. The body responds to trauma in the piriformis by pushing fluid to the area causing it to swell. The swelling then compresses the nerves within the piriformis causing a pain response. By injecting cortisone steroids into the piriformis, the compression around these nerves is reduced and the pain is minimized.

Application of Piriformis Injections

Piriformis injections are a simple outpatient procedure. A typically piriformis injection will begin with the doctor having the patient lay on their side with their knees bent towards their chest. The doctor will examine the patient by pushing various portions of their buttocks to find the spot or trigger points which are the most painful. These sites are typically where the muscles and nerves are most inflamed or tight.

After the source is found, a doctor will place an electrode on the portion of the buttocks which induced the largest pain response. The electrode is connect to an electronic nerve stimulator and a second wire is connected to a special insulated needle. The effected area is then cleaned with an antiseptic solution and numbed with local anesthetic.

The doctor will insert the insulated needle into the piriformis muscle and allow a small electrical current to pass through this needle into the muscle. The needle will cause a mild contraction of the muscle which will help the doctor more precisely locate the area which is causing the pain. Finally, the doctor will inject the steroid and local anesthetic into the piriformis and allow it to take hold within the muscle.

Most injections will take 3 to 7 days before providing relief. Additionally, the injection may cause a bit of swelling in the first few days after its application. These injections are typically followed by a routine to stretch and exercise the piriformis. Some individuals may also need follow-up appointments after the initial injection to examine the pace of recovery or to administer further injections.

Piriformis Injections Latest Research / Risks

Steroid injections have been shown to produce an anti-inflammatory response in the body. This response reduces the compression of nerves in the piriformis thereby reducing the pain an individual experiences. Although evidence for the efficacy of steroids in cases of chronic musculoskeletal pain is inconclusive, steroid injections have proven helpful in the treatment of carefully selected patients.

Though steroid injections are a viable option for piriformis pain management, these treatments run several risks. The most common complications with piriformis injections are:

  • Joint infection
  • Nerve damage
  • Temporary flare of pain and inflammation in the joint
  • Tendon weakening or rupture
  • Thinning of skin and soft tissue around the injection site
  • Thinning of nearby bone (osteoporosis)
  • Death of nearby bone (osteonecrosis)
  • Whitening or lightening of the skin around the injection site

Of these risks, nerve damage and muscle, bone, and soft tissue degradation are the most common.

Nerve Damage

If complications in steroid injections do occur, nerve damage is highly likely. Nerve injury can typically be felt immediately at the time of injection. If a nerve is damaged during the procedure, a patient will feel a shooting pain along with sensory distortion, motor weakness, and muscle atrophy. Appropriate needle positioning is vital in order to avoid nerve complications during a piriformis injection. Once nerve damage is present, surgical exploration is often the only way to manage the issue.

Muscle, Bone, And Soft Tissue Degradation

Prolonged use of steroids can weaken the injection site’s muscle, bone, and soft tissue foundations. Tissue problems experienced after steroid injections typically develop as a slowly progressive, painless weakness. Overtime, these weaknesses become more apparent and eventually can become immobilizing. Although these problems arise most commonly near the injection site, steroids may leak out to other parts of the body and lead to damage elsewhere.

Conventional Treatment Options for Piriformis Pain

Though steroid injections are a common choice for patients seeking relief from piriformis pain, doctors will typically recommend that a patient attempts conventional treatment beforehand. These conventional treatment options include:

  • Nonsteroidal anti-inflammatory drugs
  • Muscle relaxants
  • Physical Therapy
  • Surgery

Nonsteroidal Anti-Inflammatory Drugs

Over-the-counter anti-inflammatory drugs such as acetaminophen have been considered the medications of choice in the management of the many conditions that manifest as low back pain, including piriformis syndrome. In a study done by the American Osteopathic Association, patients using NSAIDs, compared with those using placebo, reported global reduction of symptoms after 1 week of treatment.

Muscle Relaxants

Muscle relaxants are another viable option for treating patients with piriformis pain. The same study by the American Osteopathic Association reported that patients using muscle relaxants were nearly five times as likely to report symptom improvement by day 14, compared with patients given placebo. Adverse consequences with low dosages or sporadic uses of muscle relaxants are minimal. Dryness of mouth, drowsiness, and dizziness are common with these low dosages. High dosages and prolonged use of muscle relaxants may have worse consequences including muscle degradation and addiction.

Physical Therapy

Though physical therapy may not have an affect on acute piriformis pain, it may provide relief to those with mild discomfort. Typically, physical therapy will require several sessions with a therapist as well as an exercise regimen outside of the therapy sessions. By increasing the muscle mass in the anterior muscles of the piriformis, physical therapy can help reduce the load the piriformis has to endure throughout the day.


Highly invasive, time consuming, and expensive, surgery is thought to be a last resort for many complications with muscles such as the piriformis. The location of the deeply nested piriformis makes surgery difficult and increases the risks inherent to surgery. Along with the surgery itself, a patient may have to apply the above listed conventional treatment methods post-surgery to help the recovery process.

Regenerative Therapy for Piriformis Pain

Though regenerative therapies have been around for the last half-century, recent advancements in the field of stem cell science have produced another viable treatment option for muscle complications such as piriformis pain. The two most common methods applied in regenerative therapy are Platelet Rich Plasma, or PRP, therapy and Stem Cell therapy.

PRP Therapy

PRP therapy is the process of extracting a patient’s blood, processing it, and then reinjecting it into the source of pain, in this case, the piriformis. The process is typically a simple outpatient procedure and by using the patient’s own blood as the source material, doctors are able to ensure that the treatment won’t be rejected by the patient’s body.

Once the blood is harvested, it is processed in a centrifuge which removes unwanted portions of the blood and isolates it’s platelets. The platelets are the body’s natural defense against injury and contain a number of growth factors which are used to amplify the body’s own healing factors. Once injected, the platelets attach to the site of injury and produce chemical signals to draw the body’s healing factors towards the site of injury.

PRP has been proven to reduce pain in muscles, tendons, and cartilage.

Stem Cell Therapy

Stem cell therapy is very similar to PRP, both treatments use the patient’s own cells in order to boost the body’s own healing processes. Whereas PRP uses a patient’s blood, stem cells are harvested from several sources, the most common of which are the patient’s fat and bone marrow. Processing these cells induces an infantile state in them where they begin to function as a typical stem cell. When these cells achieve this new state, they are considered mesenchymal stem cells.

Mesenchymal stem cells function exactly as typical stem cells. Once these cells are injected into the site of injury, they create an environment suitable for the body to regenerate damaged tissues. In a piriformis injury, this expresses itself as a decrease in inflammation along with a better response from the body if the nerves in the piriformis become aggravated again.

These techniques are often used in unison with MRI technology in order to accurately place the injection into the site of piriformis pain. After the injection, patients will typically experience a brief period of swelling which goes away within a few days. Once the swelling has subsided, these treatments keep working, creating an atmosphere suitable for repair as well as providing the area with the building blocks it needs to regenerate the damaged tissue. While stem cells and PRP can be used alone, they are typically applied in unison to amplify the healing effect. Patients can typically expect results to last anywhere from 6 months to a year from a single treatment.


Piriformis pain can be debilitating. It can make an individual unable to comfortably stand, sit, or rest. Steroid injections for piriformis pain can have grave consequences, including muscle, bone, or soft tissue degradation. These injections can cause worse problems than the one they were trying to treat.

Conventional treatment options are the most commonly administered, though they are accompanied by extended recovery periods, addiction, and invasions to a patient’s lifestyle. Recent discoveries in regenerative sciences have granted doctors the ability to not only treat a patient’s piriformis pain, but the underlying causes of it as well.

If you would like to discuss regenerative treatment options, contact the CELLAXYS offices today for more information.

Dr. Matthew HC Otten

Dr. Matthew HC Otten

Director of Regenerative Orthopedic and Sports Medicine
Fellowship-trained & Board Certified in Sports medicine
Director Angiography at Harvard Clinical Research Institute
Michigan State University Alumni


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