Pseudosciatica or Piriformis Syndrome?

Have you recently been experiencing severe back pain even though you do not have a herniated disc, or pain spreading from your lower back to your buttock when sitting for long periods or standing? In particular, have you had to receive injections frequently lately for another condition? Be aware that you may be experiencing Piriformis Syndrome, also known as pseudosciatica...

Although its symptoms resemble those of sciatica, Piriformis Syndrome is an entirely different condition. We learned about what is not yet known regarding Piriformis Syndrome from the Orthopedics and Traumatology specialists at Hisar Hospital Intercontinental.

What is Piriformis Syndrome?

First described in 1928 by Yeoman, who defined the condition as a sterile (non-infectious) inflammation of the sciatic nerve. The disease develops as a result of compression of the sciatic nerve, either through temporary spasm or chronic contracture of the piriformis muscle, and mimics the radicular pain of disc herniations. For this reason, the condition is also referred to as "pseudosciatica."

Piriformis Syndrome is a clinical condition that arises when the sciatic nerve becomes trapped beneath the piriformis muscle and is often confused with lumbar disc herniation. Historically, repeated intramuscular injections into the hip are thought to play an important role in the development of the disease. In reality, anatomical variations, hardening of the piriformis muscle, joint stiffness and some external factors lead to the condition. The piriformis muscle is a flat, pyramid-shaped muscle with an oblique position that begins in front of the sacral vertebrae and attaches to the posterior part of the femur. When the hip is extended, it rotates the thigh outward; when the thigh is flexed, it helps the legs move apart from each other.

A blunt blow to the hip, and nodular thickening that follows hematoma formation in the short external rotator muscles, can cause compression of the sciatic nerve. Sometimes a severe blow to the hip can cause similar complaints by occluding the very fine vessels that supply the nerve, leading to damage of the nerve.

What causes Piriformis Syndrome?

The common belief is that abscess, bleeding and scar formation that may occur after intramuscular injections lead to the disease. However, there is no evidence for this. The majority of patients also have no history of intramuscular injection. Other suspected causes of the disease include excessive hollowing of the lower back (lumbar lordosis), abnormal enlargement of the muscle, and nerve abnormalities (anatomical variations). A pseudoaneurysm of the inferior gluteal artery and prolonged sitting during neurosurgical procedures may also be counted among other rare causes. Piriformis Syndrome is encountered in bodybuilders, athletes who engage in jumping sports, and long-distance runners. In these individuals, excessive development of the piriformis muscle is thought to play a role in the formation of the disease. Piriformis Syndrome is seen in approximately 6% of cases on average, and it has been observed 6 times more often in women than in men. Considering that some cases are misdiagnosed, and that 90% of the adult population experiences low back pain at least once a year, this rate may be higher.

What are the clinical findings of Piriformis Syndrome?

Clinically, radicular pain spreading from the lower back to the buttock, similar to that of lumbar disc herniation, dominates the picture. In patients who have no root compression or only minimal compression but have marked sciatic pain, i.e., pain spreading from the back to the buttock, we must strongly suspect Piriformis Syndrome. 50% of patients have a history of trauma. The injury is either a direct blow to the buttock or a twisting injury of the hip. On deep manual examination, the piriformis muscle is found to be tender. Forced abduction and external rotation of the thigh against resistance (Pace Test), the occurrence of severe sciatic pain, and pain when the patient lies supine with the thigh extended and is forced into internal rotation (Freiberg Test) are quite helpful in clinical diagnosis. Pain in the thigh and hip while standing, difficulty sitting, and tension when standing with the patient in the prone position are other clinical findings of Piriformis Syndrome. There are no specific findings in laboratory tests in Piriformis Syndrome. No pathology is detected on conventional radiographs. Lumbar computed tomography and Magnetic Resonance (MR) imaging are useful for ruling out lumbar disc herniation. The most useful and accurate diagnostic method for Piriformis Syndrome is MR imaging of the hip, in which the sciatic nerve and piriformis muscle can be clearly identified.

How is Piriformis Syndrome treated?

In rehabilitation, efforts are made to lengthen the piriformis muscle. Stretching exercises and Pilates are among the methods applied for this purpose. Lifestyle adjustments are also recommended for the patient, restricting activities that provoke pain. Sitting cross-legged, sitting on hard surfaces for long periods, and jumping sports are prohibited. The patient is asked to perform stretching exercises at home every morning. In recent years, successful results have been achieved with manipulative rehabilitation programs, which have gained popularity, and with nerve and muscle mobilization treatments. Drug therapy is partially effective. There are published reports of successful cortisone injections performed under ultrasonography or computed tomography guidance. Surgical treatment is necessary for patients whose pain does not resolve despite physical therapy and injections. The muscle is released by cutting it at its point of attachment to the femur.