Diagnostic Accuracy of Clinical Tests and Diagnostic Criteria for Piriformis Syndrome

Evaluation of the Diagnostic Accuracy of Diagnostic Criteria and Clinical Tests for Piriformis Syndrome

Piriformis syndrome is a clinical condition characterized by buttock pain and/or sciatic-like symptoms, and its diagnosis remains challenging because there is no universally accepted diagnostic standard. This study aims to evaluate the diagnostic accuracy of commonly used diagnostic criteria and clinical tests for piriformis syndrome. Participants with suspected piriformis syndrome will undergo standardized physical examination and assessment of predefined diagnostic criteria. Ultrasound-guided injection of 5 mL of 2% lidocaine into the piriformis muscle will be used as the reference diagnostic procedure. A reduction of 50% or more in pain after injection will be considered confirmation of piriformis syndrome. The diagnostic performance of clinical tests and diagnostic criteria will be analyzed accordingly.

Study Overview

• Status: Not yet recruiting
• Conditions: Piriformis Syndrome; Gluteal Pain
• Intervention / Treatment: Diagnostic test: Ultrasound-Guided Piriformis Injection

Detailed Description

Piriformis syndrome is one of the possible causes of buttock pain and sciatica-like symptoms; however, its diagnosis is often difficult because of symptom overlap with lumbar radiculopathy, sacroiliac joint disorders, and other musculoskeletal conditions. In clinical practice, several physical examination maneuvers and diagnostic criteria are used, but their diagnostic accuracy has not been sufficiently established.

The aim of this study is to evaluate the diagnostic accuracy of predefined diagnostic criteria and commonly used clinical tests for piriformis syndrome. Adult participants with suspected piriformis syndrome will be recruited prospectively. All participants will undergo a standardized clinical assessment including history taking, physical examination, and evaluation of predefined diagnostic criteria and provocation tests. Clinical examinations will be performed by two physicians according to the study protocol.

As the reference diagnostic procedure, participants will undergo ultrasound-guided injection of 5 mL of 2% lidocaine into the piriformis muscle. The injection will be performed by an experienced physician under ultrasound guidance. Pain severity will be assessed before and after the procedure. A decrease of 50% or more in pain following injection will be accepted as confirmation of piriformis syndrome.

The diagnostic performance of each clinical test and diagnostic criterion set will be evaluated against this reference standard. Sensitivity, specificity, predictive values, likelihood ratios, and overall diagnostic accuracy will be analyzed. The findings of this study are expected to contribute to the development of a more standardized, reliable, and clinically applicable diagnostic approach for piriformis syndrome.

• Study Type: Interventional
• Enrollment (Estimated): 75
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Busra Nur Aslantas, MD; Phone Number: +905075985562; Email: busra.kaya1@iuc.edu.tr

Study Locations

• Turkey (Türkiye)
  • Istanbul, Turkey (Türkiye)
    • Istanbul University-Cerrahpasa, Cerrahpasa Medical Faculty
    • Contact: Busra Nur Aslantas, MD; Phone Number: +905075985562; Email: busra.kaya1@iuc.edu.tr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adults aged 18 to 75 years
• Presentation with gluteal pain
• Pain on palpation in the piriformis region

Exclusion Criteria:

• History of injection to the lumbar, hip, or gluteal region within the last 3 months,including steroid, hyaluronic acid, or similar injections
• History of hip surgery
• Presence of active inflammatory rheumatic disease, including rheumatoid arthritis, ankylosing spondylitis, polymyalgia rheumatica, vasculitis, or similar conditions
• Active skin or subcutaneous soft tissue infection in the gluteal region
• Use of anticoagulant therapy that may contraindicate injection
• Presence of a bleeding disorder
• Uncontrolled diabetes mellitus and/or hypertension
• History of neurological disease
• Pregnancy or lactation
• Presence of a psychiatric disorder
• Known allergy to the injection agents
• History of malignancy

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Participants With Suspected Piriformis Syndrome; Participants with suspected piriformis syndrome will undergo standardized clinical assessment and the diagnostic intervention defined as Ultrasound-Guided Piriformis Injection, consisting of ultrasound-guided injection of 5 mL of 2% lidocaine into the piriformis muscle.	Diagnostic test: Ultrasound-Guided Piriformis Injection; Ultrasound-guided injection of 5 mL of 2% lidocaine into the piriformis muscle for diagnostic confirmation. A patient-reported pain reduction of 50% or more at 1 hour after injection will be considered confirmation of piriformis syndrome.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Diagnostic accuracy of clinical tests and diagnostic criteria for piriformis syndrome	Diagnostic accuracy of predefined clinical tests and diagnostic criteria will be evaluated using pain response to ultrasound-guided piriformis injection as the reference standard. A positive reference standard result will be defined as a patient-reported reduction of 50% or more in pain at 1 hour after injection compared with pre-injection pain. Participants with a positive reference standard result will be classified as having piriformis syndrome for the diagnostic accuracy analysis.	Same day; pain response assessed 1 hour after injection

Collaborators and Investigators

• Sponsor: Istanbul University - Cerrahpasa

Publications and helpful links

General Publications

• Misirlioglu TO, Akgun K, Palamar D, Erden MG, Erbilir T. Piriformis syndrome: comparison of the effectiveness of local anesthetic and corticosteroid injections: a double-blinded, randomized controlled study. Pain Physician. 2015 Mar-Apr;18(2):163-71.
• Hopayian K, Danielyan A. Four symptoms define the piriformis syndrome: an updated systematic review of its clinical features. Eur J Orthop Surg Traumatol. 2018 Feb;28(2):155-164. doi: 10.1007/s00590-017-2031-8. Epub 2017 Aug 23.
• Michel F, Decavel P, Toussirot E, Tatu L, Aleton E, Monnier G, Garbuio P, Parratte B. The piriformis muscle syndrome: an exploration of anatomical context, pathophysiological hypotheses and diagnostic criteria. Ann Phys Rehabil Med. 2013 May;56(4):300-11. doi: 10.1016/j.rehab.2013.03.006. Epub 2013 Apr 30.

Study record dates

Study Major Dates

• Study Start (Estimated): March 15, 2026
• Primary Completion (Estimated): September 15, 2026
• Study Completion (Estimated): September 15, 2026

Study Registration Dates

• First Submitted: March 11, 2026
• First Submitted That Met QC Criteria: March 13, 2026
• First Posted (Actual): March 16, 2026

Study Record Updates

• Last Update Posted (Actual): March 17, 2026
• Last Update Submitted That Met QC Criteria: March 14, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Sciatica; Diagnostic Accuracy; Ultrasound-Guided Injection; Piriformis Syndrome; Clinical Tests; Gluteal Pain; Diagnostic Criteria
• Additional Relevant MeSH Terms: Pain; Neurologic Manifestations; Nervous System Diseases; Neuromuscular Diseases; Peripheral Nervous System Diseases; Neuralgia; Pelvic Pain; Mononeuropathies; Nerve Compression Syndromes; Sciatic Neuropathy; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Sciatica; Piriformis Muscle Syndrome
• Other Study ID Numbers: CTFPIR2025

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: The plan for sharing individual participant data has not yet been determined.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No