Piriformis Muscle SyndromePhase 2PiriToxNCT07624045
Efficacy of Botulinum Toxin Versus Placebo on Pain and Health Related Quality of Life of Patients With Piriformis Muscle Syndrome
A Phase 2 study testing Botulinum Toxin - A injections in people with Piriformis Muscle Syndrome, run by Centre Hospitalier Universitaire de Nīmes at 7 sites in France.
Trial summary
Piriformis muscle syndrome (PMS) is characterized by symptoms caused by compression or irritation of the sciatic nerve by the piriformis muscle as it exits the sciatic notch. PMS commonly evokes the symptoms of sciatica and is likely underdisagnosed. Read more about this study
- Who is it for?
- Ages 18 to 80 years
- Conditions the study is for
- Piriformis Muscle Syndrome
- What is being tested?
- Botulinum Toxin - A injections
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 108 participants
- Where
- 7 sitesFrance
- Study dates
- Jan 2027to Jul 2029
- Phase
- Phase 2
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 80 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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).
Who cannot join
- 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.
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- 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.
Trial locations and contacts
7 sites in 1 country. Contact the study team or a site near you to ask about taking part.
7 sites in 1 country
France7 sites
CHU de Besançon
Besançon
Fabrice MICHEL, 03 81 66 89 50, fmichel@chu-besancon.fr
CHU de Bordeaux
Bordeaux
Mathieu DE-SEZE, 05.56.79.56.79, mathieu.de-seze@chu-bordeaux.fr
CHU de Nantes
Nantes
Julien LABARRE, 02 53 48 21 87, julien.labarre@chu-nantes.fr
Centre Hospitalier Universitaire de Nîmes
Nîmes, Gard, 30029
Anissa Megzarri, 04 66 68 68 68, drc@chu-nimes.fr
Hôpital Universitaire Paris Cochin
Paris
François RANNOU, 01 58 41 23 35, francois.rannou@aphp.fr
Institut Universitaire de Réadaptation Clémenceau
Strasbourg
Marie-Eve ISNER-HOROBETI, 03.88.21.16.39, marieeve.isner@gmail.com
CHU de Toulouse
Toulouse
About this study
Official title: A Phase IIb, Randomized, Double-blind, Multicenter Study Evaluating the Efficacy of Botulinum Toxin Versus Placebo on Pain and Health Related Quality of Life of Patients With Piriformis Muscle Syndrome
Piriformis muscle syndrome (PMS) is characterized by symptoms caused by compression or irritation of the sciatic nerve by the piriformis muscle as it exits the sciatic notch. PMS commonly evokes the symptoms of sciatica and is likely underdisagnosed. Patients who experience pain related to piriformis syndrome will complain of aggravated pain after prolonged periods of sitting or upon rising from a seated position. Around 98% of patients evoke positional buttock pain, especially during prolonged sitting (car journeys, for example). This is less true for sciatic pain radiation, which is still found in 63% of cases, systematically associated with the notion of buttock pain. Treatments for PMS aim to reduce or eliminate sciatic pain and also control buttock pain. Reducing these pains can improve the physical condition and emotional state of the patient. Several approaches have been proposed including physical therapy (massage-physiotherapy, self-rehabilitation techniques) combined with the use of anti-inflammatory drugs, analgesics and muscle relaxants to reduce inflammation, spasm and pain. Many patients do not respond to conventional care. Surgery may be considered only in those cases who do not improve with conservative therapy or injections. However, decompressive surgery is an invasive treatment, indicated in case of complete failure of all medical strategies, with physical and functional consequences. In recent years, several published studies showed the use of botulinum toxin (BT) injection as a new therapeutic option to reduce buttock and sciatic pain induced by PMS. The study team previously observed the efficacy of BT/A1 administration into the piriformis muscle in patients who were previously treated with medication and rehabilitation protocols with no pain improvement. Pain relief was considered as "very good" or "good" for 77% of the patients, "average" for 7.4% and "poor" for 15.6%. No adverse events were reported. More recently, Fishman and colleagues reported the results of a randomized, double-blind, controlled study including 56 patients and comparing physical therapy, incobotulinum toxin A and placebo. Data are sparse concerning BT injection for PMS and no multicenter randomized clinical trial have been performed. Two out of three randomized trials (Fishman 2004, 2017) are based on highly selected patients (3 standard deviations or more beyond on the prolongation of the posterior tibial or fibular nerve H-reflex in FAIR test). Therefore, BT efficacy may be overestimated and remains to be evaluated among unselected PMS patients, regardless of analgesic treatments or physical therapy. Finally, no randomized studies have reported the heatlh-related quality of life of PMS patients.
- Conditions
- Piriformis Muscle Syndrome
- Being tested
- Botulinum Toxin - A injections, Placebo
- Medical subject headings
- Piriformis Muscle Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Botulinum Toxin - A injectionsDrug
Incobotulinumtoxin type A (200 U in 2 mL of preservative-free normal saline) will be injected in equally divided doses (1mL; 100 U for incobotulinumtoxin A) into 2 locations in the affected buttock region
PlaceboDrug
Placebo (normal saline solution and excipients described in Xeomin) will be injected in equally divided doses (1mL) into 2 locations in the affected buttock region
| Study group | Role | What they receive |
|---|---|---|
| Botulinum toxin injection | Experimental | Not described Receives: Drug: Botulinum Toxin - A injections |
| Placebo injection | Placebo comparator | Not described Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in sciatic pain
Measured on a 0 (no pain) to 10 (worst pain) visual analog scale
Measured: From baseline to Week 6
Secondary outcomes (52)
Change in buttock pain intensity
Measured on a 0 (no pain) to 10 (worst pain) visual analog scale
Measured: From baseline to Week 6
Health-related quality of life
EuroQol-5 Dimension questionnaire measuring five items representing the five dimensions, and a visual analog scale graduated from 0 to 100 (100 referring to the "best possible state of health"). For each dimension, patients indicate their current state of health to generated a 5-digit number describing the health status (e.g., health status "11111" indicates the absence of problems in each dimension)
Measured: Baseline
Health-related quality of life
EuroQol-5 Dimension questionnaire measuring five items representing the five dimensions, and a visual analog scale graduated from 0 to 100 (100 referring to the "best possible state of health"). For each dimension, patients indicate their current state of health to generated a 5-digit number describing the health status (e.g., health status "11111" indicates the absence of problems in each dimension)
Measured: Week 6
Health-related quality of life
EuroQol-5 Dimension questionnaire measuring five items representing the five dimensions, and a visual analog scale graduated from 0 to 100 (100 referring to the "best possible state of health"). For each dimension, patients indicate their current state of health to generated a 5-digit number describing the health status (e.g., health status "11111" indicates the absence of problems in each dimension)
Measured: Week 12
Health-related quality of life
EuroQol-5 Dimension questionnaire measuring five items representing the five dimensions, and a visual analog scale graduated from 0 to 100 (100 referring to the "best possible state of health"). For each dimension, patients indicate their current state of health to generated a 5-digit number describing the health status (e.g., health status "11111" indicates the absence of problems in each dimension)
Measured: Week 18
Health-related quality of life
EuroQol-5 Dimension questionnaire measuring five items representing the five dimensions, and a visual analog scale graduated from 0 to 100 (100 referring to the "best possible state of health"). For each dimension, patients indicate their current state of health to generated a 5-digit number describing the health status (e.g., health status "11111" indicates the absence of problems in each dimension)
Measured: Week 24
Sciatic pain intensity
Assessed on Visual Analog Scale value (0 = no pain, 10 = worst pain)
Measured: Baseline
Sciatic pain intensity
Assessed on Visual Analog Scale value (0 = no pain, 10 = worst pain)
Measured: Week 3
Sciatic pain intensity
Assessed on Visual Analog Scale value (0 = no pain, 10 = worst pain)
Measured: Week 6
Sciatic pain intensity
Assessed on Visual Analog Scale value (0 = no pain, 10 = worst pain)
Measured: Week 9
Sciatic pain intensity
Assessed on Visual Analog Scale value (0 = no pain, 10 = worst pain)
Measured: Week 12
Sciatic pain intensity
Assessed on Visual Analog Scale value (0 = no pain, 10 = worst pain)
Measured: Week 15
Sciatic pain intensity
Assessed on Visual Analog Scale value (0 = no pain, 10 = worst pain)
Measured: Week 18
Sciatic pain intensity
Assessed on Visual Analog Scale value (0 = no pain, 10 = worst pain)
Measured: Week 21
Sciatic pain intensity
Assessed on Visual Analog Scale value (0 = no pain, 10 = worst pain)
Measured: Week 24
Buttock pain intensity
Assessed on Visual Analog Scale value (0 = no pain, 10 = worst pain)
Measured: Baseline
Buttock pain intensity
Assessed on Visual Analog Scale value (0 = no pain, 10 = worst pain)
Measured: Week 3
Buttock pain intensity
Assessed on Visual Analog Scale value (0 = no pain, 10 = worst pain)
Measured: Week 6
Buttock pain intensity
Assessed on Visual Analog Scale value (0 = no pain, 10 = worst pain)
Measured: Week 9
Buttock pain intensity
Assessed on Visual Analog Scale value (0 = no pain, 10 = worst pain)
Measured: Week 12
Buttock pain intensity
Assessed on Visual Analog Scale value (0 = no pain, 10 = worst pain)
Measured: Week 15
Buttock pain intensity
Assessed on Visual Analog Scale value (0 = no pain, 10 = worst pain)
Measured: Week 18
Buttock pain intensity
Assessed on Visual Analog Scale value (0 = no pain, 10 = worst pain)
Measured: Week 21
Buttock pain intensity
Assessed on Visual Analog Scale value (0 = no pain, 10 = worst pain)
Measured: Week 24
Physical functioning
Brief Pain Inventory Short Form; 9-item questionnaire, where Worst Pain Score: 1 - 4 = Mild Pain; Worst Pain Score: 5 - 6 = Moderate Pain; Worst Pain Score: 7 - 10 = Severe Pain
Measured: Baseline
Physical functioning
Brief Pain Inventory Short Form; 9-item questionnaire, where Worst Pain Score: 1 - 4 = Mild Pain; Worst Pain Score: 5 - 6 = Moderate Pain; Worst Pain Score: 7 - 10 = Severe Pain
Measured: Week 6
Physical functioning
Brief Pain Inventory Short Form; 9-item questionnaire, where Worst Pain Score: 1 - 4 = Mild Pain; Worst Pain Score: 5 - 6 = Moderate Pain; Worst Pain Score: 7 - 10 = Severe Pain
Measured: Week 12
Physical functioning
Brief Pain Inventory Short Form; 9-item questionnaire, where Worst Pain Score: 1 - 4 = Mild Pain; Worst Pain Score: 5 - 6 = Moderate Pain; Worst Pain Score: 7 - 10 = Severe Pain
Measured: Week 18
Physical functioning
Brief Pain Inventory Short Form; 9-item questionnaire, where Worst Pain Score: 1 - 4 = Mild Pain; Worst Pain Score: 5 - 6 = Moderate Pain; Worst Pain Score: 7 - 10 = Severe Pain
Measured: Week 24
Perceived change in condition in response to therapy
Patient Global Impression of Improvement (PGI-I)
Measured: Baseline
Perceived change in condition in response to therapy
Patient Global Impression of Improvement (PGI-I)
Measured: Week 6
Perceived change in condition in response to therapy
Patient Global Impression of Improvement (PGI-I)
Measured: Week 12
Perceived change in condition in response to therapy
Patient Global Impression of Improvement (PGI-I)
Measured: Week 18
Perceived change in condition in response to therapy
Patient Global Impression of Improvement (PGI-I)
Measured: Week 24
Emotional distress
Hospital Anxiety and Depression Scale (HADS); 14 items, with responses scored on a scale of 0-3 (3 indicates higher symptom frequencies). Subscales (anxiety and depression) range from 0 to 21 whereby: normal 0-7, mild 8-10, moderate 11-14, and severe 15-21.
Measured: Baseline
Emotional distress
Hospital Anxiety and Depression Scale (HADS); 14 items, with responses scored on a scale of 0-3 (3 indicates higher symptom frequencies). Subscales (anxiety and depression) range from 0 to 21 whereby: normal 0-7, mild 8-10, moderate 11-14, and severe 15-21.
Measured: Week 6
Emotional distress
Hospital Anxiety and Depression Scale (HADS); 14 items, with responses scored on a scale of 0-3 (3 indicates higher symptom frequencies). Subscales (anxiety and depression) range from 0 to 21 whereby: normal 0-7, mild 8-10, moderate 11-14, and severe 15-21.
Measured: Week 12
Emotional distress
Hospital Anxiety and Depression Scale (HADS); 14 items, with responses scored on a scale of 0-3 (3 indicates higher symptom frequencies). Subscales (anxiety and depression) range from 0 to 21 whereby: normal 0-7, mild 8-10, moderate 11-14, and severe 15-21.
Measured: Week 18
Emotional distress
Hospital Anxiety and Depression Scale (HADS); 14 items, with responses scored on a scale of 0-3 (3 indicates higher symptom frequencies). Subscales (anxiety and depression) range from 0 to 21 whereby: normal 0-7, mild 8-10, moderate 11-14, and severe 15-21.
Measured: Week 24
Disability for low back pain
Oswestry Disability Index (ODI): range 0 to 100. Zero is equated with no disability and 100 is the maximum disability possible.
Measured: Baseline
Disability for low back pain
Oswestry Disability Index (ODI): range 0 to 100. Zero is equated with no disability and 100 is the maximum disability possible.
Measured: Week 6
Disability for low back pain
Oswestry Disability Index (ODI): range 0 to 100. Zero is equated with no disability and 100 is the maximum disability possible.
Measured: Week 12
Disability for low back pain
Oswestry Disability Index (ODI): range 0 to 100. Zero is equated with no disability and 100 is the maximum disability possible.
Measured: Week 18
Disability for low back pain
Oswestry Disability Index (ODI): range 0 to 100. Zero is equated with no disability and 100 is the maximum disability possible.
Measured: Week 24
Tolerance of the sitting position
Time between the beginning of the sitting position and the onset or worsening of the pain
Measured: Baseline
Tolerance of the sitting position
Time between the beginning of the sitting position and the onset or worsening of the pain
Measured: Week 6
Tolerance of the sitting position
Time between the beginning of the sitting position and the onset or worsening of the pain
Measured: Week 12
Tolerance of the sitting position
Time between the beginning of the sitting position and the onset or worsening of the pain
Measured: Week 18
Tolerance of the sitting position
Time between the beginning of the sitting position and the onset or worsening of the pain
Measured: Week 24
Consumption of painkillers
Number of level 1 to 3 analgesics, non-steroidal anti-inflammatory drugs and muscle relaxants
Measured: Week 24
Number of patients requiring a second injection botulinum toxin in each arm
Number
Measured: Week 12
Side effects of injection
Side effects of the injection or attributable to the study drug
Measured: Week 24
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted3 Jun 2026
- Study startJan 2027 (estimated)
- Primary completionJul 2029 (estimated)
- Study completionJul 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Piriformis Muscle SyndromeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Investigator, Outcomes assessor
- Enrolment
- 108 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Centre Hospitalier Universitaire de Nīmes
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Arnaud Dupeyron, Principal investigator, CHU Nîmes
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07624045
- Sponsor's protocol ID
- PHRCN/2019/AD-1
- Other IDs
- 2024-517948-66-00
- Acronym
- PiriTox
- Status last verified
- Oct 2026
- First submitted
- 29 May 2026
- Last updated
- 21 Oct 2026
- Results posted
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No