Botox injection may ease stubborn buttock and leg pain

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Objective clinical diagnosis of unilateral piriformis syndrome for at least 3 months (as assessed by Clinical Scoring System for the Diagnosis of Piriformis Muscle Syndrome: score of 8 or greater * Absence of herniated lumbar disc which can explain radiating pain (MRI or computed tomography (CT) of the lumbar spine) * Patients not responding to conventional care (physiotherapy, muscle relaxants, analgesics) * Baseline sciatic pain intensity of at least 4 points on visual analog scale * Provision of written informed consent * Patients affiliated to social security system (health insurance coverage). Exclusion Criteria: * Bilateral piriformis muscle syndrome. * History of piriformis syndrome surgery. * History of botulinum toxin administration. * Any treatment (general or local) likely to interfere with botulinum toxin or evaluation of the primary endpoint (Corticosteroids, aminoglycosides). * Corticosteroids in the past 3 weeks. * Signs of severe fibrosis (on MRI or CT) of the piriformis muscle. * Other causes of sciatic pain (lumbar root compression, inflammatory, infectious or neoplasic pelvic disease, particularly for inflammatory sacroiliac pain). * Hip prosthesis on the same side as piriformis syndrome; knee prosthesis is tolerated. * Contraindication to BT injection: * History of intolerance, hypersensitivity or known allergy to any botulinum toxin product or excipients; * Patients with myasthenia gravis or other diseases of the neuromuscular junction; * Patients with Lambert-Eaton Syndrome; * Patients with neurological disorders such as dysphagia, swallowing disorders or aspiration pneumonia; * Current infection at the proposed injection site; * Long-term anticoagulant therapy ; * Antibiotics and vaccination are prohibited for 15 days before and after BT injection * Pregnant or breastfeeding women. Women of child-bearing potential, defined as all women physiologically capable of becoming pregnant must use an effective method of contraception (oral contraceptives, contraceptive injections, intrauterine devices, method of double-barrier contraceptive patches). The contraception should be maintained throughout the study. * Patients unable to complete the patient diary. * Inability to understand the reasons for the study; psychiatric disorders judged by the investigator to be incompatible with inclusion in the study. * Patients with legal disability or limited legal capacity. * Patients judged as noncompliant.