33-year-old Woman with Piriformis Syndrome

The case study focuses on a 33-year-old woman who has a four-year history of right buttock pain. She has had a variety of evaluations and a series of epidural injections with little benefit. A Botox injection has been recommended but she has not proceeded with this because of her experience with other injections have been too painful. Her in-network physicians have made a tentative diagnosis of a right sided Piriformis Syndrome, however, due to lack of Open MR guidance capability within her insurance plan, she is now referred for further evaluation and management.

Upon specialized neurological examination, the pain is really limited to the right buttock and upper leg. There is no reproduction of pain with straight leg raised, but she does have reproduction of symptoms with resisted adduction on the right side. She has weakness for abduction in that position as well. She finds the greatest problems are when sitting and driving, and she has increasingly been limited in the distance she can drive without symptoms.

PREVIOUS RADIOLOGIC STUDIES: Review of radiologic studies includes a pelvis MRI, pelvic CT scan and lumbar spine imaging. None of these images demonstrate any significant pathology. According to the imaging conducted within network, the Piriformis muscles appear to be symmetric.

IMPRESSION AND PLAN: Based on this history, physical exam, and findings, The Neurography Institute’s Dr. Aaron G. Filler believes this is a very convincing case of Piriformis Syndrome. However, in order to be certain of the diagnosis and to try and avoid the necessity of surgery, he recommends we carry out an MRI image-guided injection of the Piriformis muscle. Based on the injection results, the patient will either have lasting relief or the imaging details will provide real-time imaging of the pain location so that a minimal invasive surgery can be completed.

MRI-GUIDED INJECTION: A series of T1-weighted images were obtained, which demonstrate the area of the pelvis and no gross abnormalities are appreciated. The Piriformis muscles are readily identified. There are then a series of 2D FLASH images, in which first the interventionist’s finger is seen to indicate the area of the Piriformis muscle. After an additional series of images, in which hypointense material appears below the skin surface consistent with the administration of local anesthetic, the needle tracer was then seen to enter and advance gradually into the Piriformis muscle. Hypointense material then gradually fills the muscle.

The needle was then withdrawn and additional T2-weighted images in the axial plane were then obtained. These demonstrate hyperintense contrast effect of the injectate, which demonstrates uniform flow throughout the Piriformis muscle.

CONCLUSION: The patient’s Piriformis injection was VERY effective; even immediately at the time of the injection, she experienced immediate pain relief when sitting in the car on the way home. Two weeks out from the Open MR-guided injection, her physical exam shows significant reduction in tenderness, pain and weakness in the right buttock and hip area. Based on this initial outcome we are hopeful that the reduction in pain conditions will continue, and that the patient will be able to avoid Piriformis surgery altogether.

As of this month, the patient has now been ten years pain-free.