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

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