Disclosures: Niketa N. Parikh, DO: No financial relationships or conflicts of interest

Case Diagnosis: A 52-year-old G0 female with chronic refractory obturator internus (OI) dysfunction and pain.

Case Description: Patient described a deep “biting” pelvic pain that radiated into the left buttock, was exacerbated by stretching and sitting, and was associated with urge urinary and fecal incontinence. She previously underwent pelvic floor physical therapy, chiropractor treatments, sacroiliac joint injection, and lumbar epidural steroid injection without improvement. Exam demonstrated intact neurologic function and tenderness over the inferior gluteal muscles. Pelvic floor exam revealed increased tone and tenderness of the left OI muscle.

Setting: Outpatient Women’s Health Musculoskeletal Clinic

Assessment/Results: Patient underwent ultrasound-guided corticosteroid TPI to the left OI via external posterior hip approach with transient 30% pain relief. She subsequently underwent a series of left intravaginal OI TPIs with lidocaine with 100% relief of her deep buttock pain. She remained pain free at 4 and 10 week follow-ups.

Discussion: Current evidence on trigger point injection (TPI) to the pelvic floor muscles is limited. This case uniquely details complete relief of myofascial pelvic floor pain after intravaginal OI TPI, following less successful relief with the posterior hip approach. The OI muscle has a fan-shaped anatomy that spans the lateral wall of the pelvic floor and the posterior hip joint. This complex anatomy reinforces the principle that distinct pain generators can exist within a single muscle, leading to different therapeutic responses based on location of dysfunction and intervention. This is illustrated by incomplete relief from the posterior hip approach, followed by full immediate relief from the intravaginal approach. This case demonstrates the utility of alternative approaches to OI injection in those with refractory symptoms.

Conclusion: This case uniquely highlights additional considerations and therapeutic interventions for patients with buttock pain and/or pelvic pain of OI origin. Moving forward, collaboration between sports medicine and pelvic floor specialists can greatly improve patient outcomes in these challenging cases.

Level of Evidence: Level V

« Back to AAPM&R Annual Assembly 2022

PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/chronic-buttock-pain-consider-intravaginal-obturator-internus-trigger-point-injection-a-case-report/