Piriformis muscle syndrome (PMS) is a neuromuscular disorder that can cause symptoms of hip joint motion limitation, buttock pain and tenderness, and numbness radiating to the back of the thigh due to compression or irritation of the sciatic nerve.In the etiology of PMS myofascial trigger points are the most common cause and also hypertrophy in the piriformis muscle tissue, inflammation, trauma, anatomical variations of the piriformis muscle or sciatic nerve may also cause the development of PMS . Physical examination supports the diagnosis of PMS and may help to eliminating competing diagnoses. Multiple physical examination maneuvers have been identified to help diagnose but no physical examination maneuver is diagnostic for PMS. Compression and deep palpation may also exacerbate buttock or gluteal pain. Electrodiagnostic tests are usually normal in FMS and useful in excluding other conditions such as lumbosacral radiculopathy .There is no gold standard treatment option for PMS, conservative treatment and lifestyle changes remain the mainstays for the treatment. Piriformis muscle stretching is the form of an exercise technique in physiotherapy method that is generally used for those patients. The exercises focused on relaxing the priformis muscle to increase the resting length of the muscle and reduce the potential sciatic nerve compression because of this thigtness. Dry needling (DN) therapy is a treatment method where myofascial trigger points are stimulated using acupuncture needles or injection needles .DN can be applied according to the anatomical landmark method or under the guidance of ultrasound (US) and fluoroscopic imaging. US guidance is important in the management of PMS, which allows imaging of specific deep muscle groups and avoids complications such as procedural pain and damage of neurovascular structures . There are no randomized controlled studies other than case series on the use and frequency of application of the US-guided DN technique in PMS. The aim of this study is to compare the effectiveness of dry needling treatment applied to the piriformis muscle once a week for a total of 3 times under US guidance and 3-week exercise program treatment in PMS. The secondary outcomes of this study is to evaluate and compare the effect of these treatment modalities on Visuel Analg Scale (VAS) scores ,Oswestry Disability Index (ODI), lower extremity functional scale (LEFS) and (Douleur Neuropathique 4 Questionare ) DN4 scores in PMS patients at 3 months follow up.

In this observational study, between January 2022 and April 2023, after excluding other hip, lumbar, sacroiliac region and lower extremity pain etiology diagnoses, 44 patients aged 18-70 years who are clinically diagnosed with PMS are planned to be included in the study. The diagnosis is based on patient's history and physical examination, bearing positive FAIR test and/or tenderness or trigger point at the priformis muscle area and/or revealing the pain with maneuvers; such as Freiberg's maneuver , Beatty's maneuver and Pace's maneuver . The demographic data (age, sex, occupation, body mass index scores), the side of the pain will be noted. Each patient in the study will receive and sign an informed consent form.The patients will divide into two groups ; group 1 (n:22)will have DN treatment to the piriformis muscle once a week for a total of 3 times under US guidance, all patients in group 2 (n:22) will have exercise programme for 3 weeks. Overall pain severity will measure by using visual analogue scale (VAS). Pain disability will assess with the Oswestry Disability Index (ODI) questionnaire, Physical function will rate with Lower Extremity Functional Scale (LEFS). Presence and severity of neuropathic pain will evaluate according to Douleur Neuropathique 4 questionnare (DN4). To identify the outcomes of the treatment modalities, pre-treatment, post-treatment 1st month and 3th-month scores will be used. Patients with comorbidities that prevented interventional treatment (e.g., inflammatory diseases, uncontrolled diabetes mellitus, uncontrolled hypertension, malignancy, pregnancy, and severe psychiatric disorders), patients with other diagnoses that may cause hip and leg pain (e.g.,lumbar disc herniation, sciatic nerve injury history, sacroiliac and hip joint pathologies) those aged under 18 years old and patients who did not accept interventional or physical therapy modalities are going to exclude from the study.

Inclusion Criteria:

• Patients with isolated Piriformis Muscle Syndrome
• The diagnosis is based on patient's history and physical examination, bearing positive FAIR (flexion, adduction, internal rotation) test and/or tenderness or trigger point at the priformis muscle area and/or revealing the pain with maneuvers; such as Freiberg's maneuver (forceful internal rotation of the extended thigh in the supine position), Beatty's maneuver (actively abducting the affected thigh in the lateral decubitus position) and Pace's maneuver (resisted abduction of both thighs in the seated position).

Exclusion Criteria:

• Patients with comorbidities that prevented interventional treatment (e.g., inflammatory diseases, uncontrolled diabetes mellitus, uncontrolled hypertension, malignancy, pregnancy, and severe psychiatric disorders),
• Patients with other diagnoses that may cause hip and leg pain (e.g.,lumbar disc herniation, sciatic nerve injury history, sacroiliac and hip joint pathologies)
• Aged under 18 years old
• Patients who will not accept interventional or physical therapy modalities

The patients were divided into two groups as those who will accept DN treatment (Group 1 -n: 22) and those who will have physical exercise treatment (Group 2- n: 22). All patients in group 1 will have DN treatment to the piriformis muscle once a week for a total of 3 times under US guidance.