Welcome to the May 2011 Case Study from the Institute for Nerve Medicine.

In this issue we explore the case of a female suffering from burning and pain that seemed to have no direct cause.

History: This patient presented with a history of left vaginal burning and right lower back/buttock pain for 3-4 years. The patient reports a sudden onset of constant left vaginal burning. There was no injury, accident, trauma prior to the onset of the injury. During a pregnancy she also developed right lower back/buttock pain. She has trialed physical therapy, dry needling, acupuncture with no relief. She has had at least four different Ob/Gyn evaluations with no significant finding. She has also been trialed on Neurontin, Lyrica, Amtriptyline, Zoloft and Elmiron. She notes that over time her symptoms have worsened in severity level. She denies any loss of sensation or strength. The patient denies any changes in bowel or bladder function. She has some relief lying down and taking baths. Her symptoms are aggravated by walking and sitting.

Physical Examination: Physical examination in the sitting position, at the hips for flexion, extension, abduction and adduction, gave some reproduction of symptoms with resisted adduction on the right. Additional directed exam in the supine position with straight leg raising, passive hip rotation, and resisted abduction and adduction of the flexed, internally rotated thigh led to some symptoms of passive external rotation, as well as resisted abduction and adduction on the right, negative throughout on the left. There is relief of symptoms with crossed leg traction bilaterally. Elevation of the extended leg against resistance had no effect on the symptoms. Palpation in the inguinal region over the obturator foramen is negative.

Additional directed exam in the standing position with palpation and percussion over the thoracic, lumbar, sacral and coccygeal spine was negative. Palpation over the posterior buttock revealed tenderness in the upper buttock bilaterally, over the sciatic notch bilaterally, over the greater trochanter bilaterally, negative on the lateral aspect of the ischial tuberosity, positive over the greater trochanter bilaterally, positive on the medial aspect of the ischial tuberosity with sitting bilaterally and positive over the lateral thigh inferior to the greater trochanter on the right side.

Plan: Based on this history, exam, data and findings, the patient was diagnosed with a bilateral syndrome involving the piriformis, obturator internus and trochanteric bursa. Due to the variation in the presentation of symptoms it is possible that the patient has anatomical differences. Some patients have piriformis pudendal syndrome and some have piriformis superior gluteal nerve syndrome, but she appears to have the superior gluteal nerve syndrome on the right and the pudendal symptoms on the left. The patient was recommended for an MR Neurography to look for evidence of anatomical variants or has nerve irritations consistent with the physical examination findings.

MR Neurography: The piriformis muscles are markedly asymmetric with the muscle on the right side significantly divided into two components and the muscle on the left a single component muscle. The sciatic nerve on the right side is split and passes partly between the two components of the piriformis muscle and there is no split of nerve or muscle on the left. The S2 and S3 spinal nerves do not pass through any portion of the piriformis muscle on the right side; however, the S2 spinal nerve does pass through a segment of the piriformis muscle on the left side. The segment of the S2 spinal nerve traversing the piriformis muscle does show some mild irritative change as it traverses the piriformis muscle. The superior gluteal nerve demonstrates hyperintensity change on the right side.

OMR Procedure: The patient was recommended to proceed with an open MRI-guided procedure for the right and left piriformis, obturator internus muscles right and left, superior trochanter and the superior gluteal nerve on the right. As seen on the images the size of the piriformis muscles would’ve made it difficult to confirm placement of medication in the piriformis muscles without proper guidance. With the use of Open MRI guidance we are able to dramatically reduce the potential for nerve injury and incorrect diagnosis due to missed targets with X-ray or CT-guidance. With this imaging the physician is assured that the target is reached by the accuracy of the MRI Guidance, and therefore can conclude based on the patient’s response if the targeted area is involved in the diagnosis.


MR Neurography Case Study Images



MR Neurography image showing extremely assymetrical piriformis muscles in the patient with sciatic and pelvic pain.



MR Neurography image showing the piriformis muscle split entirely by the large tendon.



Dual MR Neurography images showing a coronal T1 view (left) and axial T1 view (right) of the extremely split piriformis muscle.



MR Neurography image captured during the injection procedure showing the extremely small piriformis musciel; the MRI-compatible needle; and the piriformis muscle very close to the patient's colon.



MR Neurography image captured during the injection procedure showing the MRI needle and injection into the small tendon space of the rare, large piriformis split.