Ultrasound-Guided Interfascial Hydrodissection for Gluteal Myofascial Pain in Piriformis Syndrome: A Prospective Study

Efficacy of Ultrasound-Guided Interfascial Hydrodissection for Myofascial Pain Syndrome of the Gluteus Maximus in Patients With Piriformis Syndrome: A Double-Blind Randomized Controlled Trial.

This randomized, double-blind prospective trial investigates whether ultrasound-guided interfascial hydrodissection using 10% dextrose is more effective than dry needling in treating gluteal myofascial pain coexisting with piriformis syndrome. Following diagnostic piriformis injection response, eligible patients will be randomized into two treatment arms and followed at 1 hour, 1 week, 1 month, and 3 months. The primary hypothesis is that interfascial hydrodissection will provide superior long-term analgesic outcomes due to fascial separation, neuromodulation, and nociceptor suppression.

Study Overview

• Status: Not yet recruiting
• Conditions: Piriformis Syndrome; Gluteus Maximus Myofascial Pain
• Intervention / Treatment: Procedure: Ultrasound-Guided Interfascial Hydrodissection; Procedure: Ultrasound-Guided Gluteus Maximus Dry Needling

Detailed Description

Piriformis syndrome (PS) is a neuromuscular condition characterized by compression or irritation of the sciatic nerve at the piriformis muscle level. Patients frequently present with unilateral gluteal pain that worsens with prolonged sitting, hip movement, or palpation over the piriformis locus. Although the neuropathic component of PS is attributed to sciatic nerve irritation, the somatic pain component is believed to arise from myofascial dysfunction within gluteal structures, particularly the piriformis muscle.

Recent clinical observations indicate that many patients diagnosed with PS also exhibit features of gluteus maximus myofascial pain syndrome (GM-MPS). The gluteus maximus muscle has a large fascial interface with the piriformis muscle, and nociceptive stimulation originating from this interface may contribute to persistent gluteal pain in PS. Despite this, the fascial contribution to symptom persistence remains poorly investigated, and therapeutic interventions are largely directed toward the piriformis alone.

Interfascial hydrodissection is an emerging ultrasound-guided technique in which liquid is injected between tissue planes to mechanically separate fascial layers, improve gliding, and modulate sensory nociceptive fibers. Dextrose solutions have been increasingly used in ultrasound-guided interfascial injections based on their proposed neuromodulatory and regenerative effects. However, evidence regarding its long-term efficacy in gluteal myofascial pain, particularly when coexisting with PS, is limited.

This prospective, randomized, double-blind clinical trial aims to evaluate the therapeutic effectiveness of interfascial hydrodissection using 10% dextrose solution between the gluteus maximus and piriformis muscles in patients with PS diagnosed through positive diagnostic injection response. Patients with ≥50% pain reduction one hour after diagnostic piriformis injection will be randomized into two treatment groups. Randomization will be performed by an independent co-investigator using a pre-prepared 1:1 allocation list. Outcome assessment will be conducted by an investigator blinded to treatment allocation. Patients will then be assigned to one of the following treatment groups: (1) ultrasound-guided interfascial hydrodissection and (2) dry needling of the gluteus maximus muscle.Both interventions will be performed under ultrasound guidance to ensure accuracy and standardization.

Outcome assessment will include numerical pain scoring, percentage pain reduction, and clinical improvement at one hour, one week, one month, and three months post-intervention. The first assessor will be blinded to treatment allocation, ensuring independent measurement of outcomes. It is hypothesized that interfascial hydrodissection will provide superior long-term pain relief compared with dry needling by separating adhered fascial planes, improving local mobility, and reducing nociceptive drive through dextrose-mediated neuromodulation.

If successful, this trial will provide the first structured evidence evaluating the role of gluteus maximus-piriformis fascial interface treatment in PS and may identify an overlooked pain generator in this common syndrome. Results could expand therapeutic options for PS, support broader application of interfascial hydrodissection, and contribute to clinical understanding of fascial pain mechanisms.

• Study Type: Interventional
• Enrollment (Estimated): 42
• 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
    • Istanbul, Istanbul, Turkey (Türkiye)
      • Istanbul University-Cerrahpasa, Cerrahpasa Faculty of Medicine
      • 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
• Buttock pain with or without radiation to the lower extremity
• Ability to understand and provide written informed consent

Exclusion Criteria:

• Active lumbar radiculopathy
• History of hip joint pathology or prior hip surgery
• Previous injection or dry needling treatment to the gluteal region within the last 3 months
• Coagulation disorders or use of anticoagulant therapy
• Pregnancy
• Local infection at the injection site
• Inability to complete the study protocol or attend follow-up visits.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Ultrasound-Guided Interfascial Hydrodissection; Ultrasound-guided interfascial hydrodissection is performed in the interfascial space between the gluteus maximus and piriformis muscles.	Procedure: Ultrasound-Guided Interfascial Hydrodissection; Ultrasound-guided interfascial hydrodissection is performed in the interfascial plane between the gluteus maximus and piriformis muscles.
Active Comparator: Ultrasound-guided gluteus maximus dry needling; Participants receive ultrasound-guided dry needling applied to the gluteus maximus muscle.	Procedure: Ultrasound-Guided Gluteus Maximus Dry Needling; Ultrasound-guided dry needling is performed on the gluteus maximus muscle without fluid administration.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pain Intensity Assessed by Numeric Rating Scale	Pain intensity is assessed using the Numeric Rating Scale (NRS, 0-10) for pain at rest, during activity, at night, while standing, sitting, lying down, and for overall pain.	3 months after the intervention

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pain Intensity Assessed by Numeric Rating Scale	Pain intensity is assessed using the Numeric Rating Scale (NRS, 0-10) for pain at rest, during activity, at night, while standing, sitting, lying down, and for overall pain.	1 week after the intervention
Pain Intensity Assessed by Numeric Rating Scale	Pain intensity is assessed using the Numeric Rating Scale (NRS, 0-10) for pain at rest, during activity, at night, while standing, sitting, lying down, and for overall pain.	1 month after the intervention

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.
• Tantanatip A, Patisumpitawong W, Lee S. Comparison of the Effects of Physiologic Saline Interfascial and Lidocaine Trigger Point Injections in Treatment of Myofascial Pain Syndrome: A Double-Blind Randomized Controlled Trial. Arch Rehabil Res Clin Transl. 2021 Mar 9;3(2):100119. doi: 10.1016/j.arrct.2021.100119. eCollection 2021 Jun.
• Kaga M, Ueda T. Effectiveness of Hydro-Dissection of the Piriformis Muscle Plus Low-Dose Local Anesthetic Injection for Piriformis Syndrome: A Report of 2 Cases. Am J Case Rep. 2022 Feb 6;23:e935346. doi: 10.12659/AJCR.935346.

Study record dates

Study Major Dates

• Study Start (Estimated): March 26, 2026
• Primary Completion (Estimated): June 28, 2026
• Study Completion (Estimated): September 28, 2026

Study Registration Dates

• First Submitted: December 24, 2025
• First Submitted That Met QC Criteria: December 24, 2025
• First Posted (Actual): January 8, 2026

Study Record Updates

• Last Update Posted (Actual): March 13, 2026
• Last Update Submitted That Met QC Criteria: March 11, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Ultrasound-guided injection; Interfascial hydrodissection; Gluteal pain
• 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; Piriformis Muscle Syndrome
• Other Study ID Numbers: CTFPIRHD2025

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Individual participant data sharing has not been decided at this stage. Although ethical approval for the study has been obtained, any potential data sharing will be considered in the future upon reasonable request and in accordance with participant consent and institutional policies.

Drug and device information, study documents

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