Investigation of the Presence of Piriformis Syndrome Accompanying Lumbar Radiculopathy

Piriformis syndrome is a neuromuscular disorder that is characterized by piriformis muscle tenderness, hip, and leg pain, and may be accompanied by compression or irritation of the sciatic nerve under the piriformis muscle. There are many studies in the literature to establish diagnostic criteria for piriformis syndrome, and there is still no clear consensus on these criteria. However, cases with lumbar radiculopathy were accepted as exclusion criteria in all these studies. The aim of our study is to investigate whether lumbar radiculopathy and piriformis syndrome can coexist. For this reason, a diagnostic piriformis muscle injection under ultrasonography guidance is planned for patients with lumbar radiculopathy who also have a prediagnosis of piriformis syndrome clinically.

Lumbar radiculopathy is a condition in which lumbar spinal nerve roots are affected due to various pathologies. The diagnosis is made clinically by the symptoms and physical examination findings. Most of the time, the diagnosis is supported by imaging methods and electrodiagnostic tests. Piriformis syndrome is a neuromuscular disorder that is characterized by piriformis muscle tenderness, hip, and leg pain, and may be accompanied by compression or irritation of the sciatic nerve under the piriformis muscle. Similarly, the diagnosis of piriformis syndrome is made clinically based on the patients' history and physical examination. In addition, piriformis muscle injections are an accepted method for the diagnosis of piriformis syndrome. However, the diagnosis of piriformis syndrome is still a controversial issue due to the absence of universally accepted diagnostic criteria, pathognomonic findings, or a gold standard diagnostic method. In this context, many authors have reported that piriformis syndrome is mostly a diagnosis of exclusion. For this reason, the diagnosis of piriformis syndrome is missed in patients with lumbar radiculopathy and these patients may apply to multiple physicians due to their ongoing pain. This can lead to loss of time, financial losses, sensitization and chronic pain in patients and even unnecessary lumbar surgery. Our aim is to investigate whether these two clinical conditions coexist by performing a diagnostic piriformis muscle injection test under ultrasonographic guidance to patients with a diagnosis of lumbar radiculopathy and also with symptoms and signs of piriformis syndrome. The diagnostic injection test into the piriformis muscle has also been reported to have therapeutic effects. Therefore, the second goal of our study is to investigate the therapeutic effect of piriformis muscle injection in patients diagnosed with lumbar radiculopathy and also piriformis syndrome.

All patients (n=40) will be evaluated with detailed physical examination and special clinical tests for both lumbar radiculopathy and piriformis syndrome. If patients have lumbar magnetic resonance imaging or electromyography results, they will be recorded to confirm the diagnosis of lumbar radiculopathy. The patients who have the final diagnosis of lumbar radiculopathy and prediagnosis of piriformis syndrome will be evaluated for the pain scores (pain at resting, sitting, standing, lying, at night and during activity) using numeric rating scale. Then, an ultrasound guided piriformis muscle injection will be performed. The patients will be kept under observation for 30 minutes afterwards and the percentage of their pain relief will be recorded. The patients whose pain resolves at least 50% from the baseline after the injection will be diagnosed as piriformis syndrome and will be reevaluated one week and one month after the injection and the changes in the pain scores will be recorded.

After the piriformis muscle injection, the percentage of relief in patient's symptoms will be questioned. It has been reported that 50% or more reduction in the patient's complaints after injecting the local anesthetic agent into the piriformis muscle, with or without steroids, is diagnostic for piriformis syndrome. Therefore, patients with at least 50% reduction in post-injection complaints will be diagnosed with piriformis syndrome.

Before the injection, the participants' pain at resting, sitting, standing, lying, at night, during activity will be assessed by one of the most commonly used pain scale 'numerical rating scale'. It is numeric version of 'visual analog scale' in which the patient selects a whole number (0-10 integers) that best reflects the intensity of his/her pain. The 11-point numeric scale ranges from '0' representing "no pain" to '10' representing "pain as bad as you can imagine". One week after the injection, the participant's pain while resting, walking, sitting, lying down and at night will be evaluated with a numerical rating scale and the change in pain scores will be evaluated. Similarly, the change in pain scores during the same activities one month after the injection will also be evaluated. In this way, the amount of relief that may be provided via the piriformis muscle injection in patients having lumbar radiculopathy and piriformis syndrome in short and medium terms will be evaluated.

Inclusion Criteria: Aged over 18 years Having clinical symptoms and signs of L4/L5/S1 radiculopathy which may be supported by imaging and/or electrodiagnostic evaluation Having tenderness at the piriformis muscle Exclusion Criteria: Injection history at the lumbar, hip, gluteal region in the last 6 months Operation history at the lumbar and/ or hip region History of inflammatory rheumatic disease History of infectious disease History of bleeding disorder History of anticoagulation use Uncontrolled diabetes mellitus or hypertension History of neurological disease Being in gestational or lactational period Noncompensated chronic heart/liver/renal deficiency, or vascular/tumoral disease Active psychiatric disease History of allergic reaction to the substance to be applied as local anesthetic

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