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.

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