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NCT07813455

Interfascial Hydrodissection Added to Ultrasound-Guided Piriformis Injection for Piriformis Syndrome

Sponsor: Haydarpasa Numune Training and Research Hospital

View on ClinicalTrials.gov

Summary

The gluteus maximus overlies the piriformis muscle and forms a broad fascial interface with it. Restricted movement, increased tension, or adhesions between these tissue layers may contribute to persistent buttock pain in piriformis syndrome. Interfascial hydrodissection is an ultrasound-guided procedure in which fluid is introduced between the gluteus maximus and piriformis muscles to gently separate restricted fascial planes, improve tissue gliding, reduce local mechanical irritation, and potentially modulate nociceptive input from pain-sensitive nerve endings within or adjacent to the fascial interface. The goal of this clinical trial is to learn whether adding ultrasound-guided interfascial hydrodissection to a piriformis injection provides better pain relief and improves function in adults with piriformis syndrome. Piriformis syndrome can cause buttock pain that may spread to the back of the thigh or leg. Interfascial hydrodissection is a procedure in which fluid is injected between the gluteus maximus and piriformis muscles. The fluid gently separates the tissue layers and may help them move more freely. The main questions this trial aims to answer are: * Does adding interfascial hydrodissection to a piriformis injection lower overall pain more than the piriformis injection alone at 3 months after treatment? * Does it provide greater improvement in pain at earlier follow-up visits, hip-related function, and overall recovery? All participants will first receive one ultrasound-guided local anesthetic injection into the piriformis muscle. The early pain response will help support the diagnosis, and the same injection will serve as the common treatment received by both groups. Participants whose pain improves by at least 50 percent will be randomly assigned to either continue with the piriformis injection alone or receive additional interfascial hydrodissection. After the 1-week assessment, participants in both groups will begin the same home-based piriformis stretching program. Participants will: * Receive one ultrasound-guided piriformis injection and, depending on group assignment, may also receive interfascial hydrodissection * Have follow-up assessments later on the treatment day and at 1 week, 1 month, and 3 months * Follow the same home-based stretching program after the 1-week assessment * Report their pain, daily function, overall improvement, pain medicine use, additional treatment needs, and any side effects

Official title: Effectiveness of Interfascial Hydrodissection Added to Ultrasound-Guided Piriformis Injection in Piriformis Syndrome: A Prospective Randomized Controlled Trial

Key Details

Gender

All

Age Range

18 Years - 70 Years

Study Type

INTERVENTIONAL

Enrollment

110

Start Date

2026-10

Completion Date

2027-07

Last Updated

2026-09-10

Healthy Volunteers

Conditions

Piriformis Syndrome

Interventions

PROCEDURE

Ultrasound-Guided Piriformis Injection

Before randomization, participants who meet the initial clinical eligibility criteria will receive one ultrasound-guided injection of 5 mL of 2% lidocaine into the piriformis muscle. The injection will have both diagnostic and therapeutic intent. The early pain response will be used to support the diagnosis and determine eligibility for randomization. In participants who demonstrate at least a 50 percent reduction in overall pain and proceed to randomization, the same injection will constitute the common active treatment received by both arms.

PROCEDURE

Ultrasound-Guided Interfascial Hydrodissection

After assessment of the early pain response and randomization, participants assigned to the experimental arm will receive one ultrasound-guided interfascial hydrodissection of the tissue plane between the gluteus maximus and piriformis muscles. Hydrodissection will be performed using a total volume of 20 mL consisting of 18 mL of 0.9% sodium chloride and 2 mL of 1% lidocaine.

BEHAVIORAL

Standardized Home-Based Piriformis Stretching Program

After completion of the 1-week assessment, participants in both arms will begin the same standardized home-based piriformis stretching program and will continue the program for 6 weeks. The exercise will be demonstrated by a member of the rehabilitation team, written instructions will be provided, and adherence will be recorded during follow-up.

Inclusion Criteria: * Age 18 to 70 years. * Buttock or gluteal pain that may radiate to the posterior thigh and/or leg. * Medical history and physical examination findings consistent with piriformis syndrome. * Tenderness on palpation over the piriformis muscle. * A positive result on at least one of the following piriformis provocation maneuvers: FAIR, Freiberg, Pace, or Beatty. * Exclusion of lumbar radiculopathy, clinically significant hip pathology, and other major causes of buttock or leg pain by clinical assessment and, when clinically indicated, review of available routine imaging. * Ability to understand and sign the written informed consent form. * Ability and willingness to attend the scheduled follow-up visits. Additional criterion for randomization: \- At least a 50 percent early reduction in overall pain after the single ultrasound-guided local anesthetic piriformis injection. Exclusion Criteria: * Active lumbar radiculopathy, clinically significant lumbar disc herniation, spinal stenosis, or another spinal disorder that could explain the participant's symptoms. * Clinically significant neurological deficit. * Marked limitation of lumbar spine and/or hip range of motion. * Previous surgery involving the lumbar spine or hip region. * Pregnancy or breastfeeding. * Known allergy or hypersensitivity to lidocaine or another local anesthetic used in the study. * Current anticoagulant treatment or a clinically significant coagulation disorder. * Active infection at the injection site. * Body mass index greater than 35 kg/m². * Active inflammatory or infectious disease that may affect participant safety or study assessments. * Active psychiatric condition that may interfere with informed consent, adherence to study procedures, or outcome assessment. * Uncontrolled hypertension. * Uncontrolled diabetes mellitus. * Decompensated cardiac, hepatic, or renal failure. * Vascular or neoplastic disease that could explain the symptoms or increase the risk of the study procedures. * Injection, dry needling, or a similar intervention in the gluteal region within the previous 3 months. * Inability or unwillingness to complete the scheduled follow-up visits.

Locations (1)

University of Health Sciences, Haydarpasa Numune Training and Research Hospital, Department of Physical Medicine and Rehabilitation

Istanbul, Uskudar, Turkey (Türkiye)