Disclosures: Vivek Nagar, MD: No financial relationships or conflicts of interest

Case Description: This case demonstrates a rare complication of neuromodulation leading to greater trochanteric pain syndrome secondary to direct irritation of gluteus medius by migration of the pulse generator.

Setting: Ambulatory clinic

Patient: 72-year-old female with history of multiple myeloma and intractable urinary incontinence status post sacral nerve stimulator three years prior presented with atraumatic right lateral thigh pain for four months. History and physical examination were suggestive of greater trochanteric pain syndrome. Hip radiographs were unremarkable. She began physical therapy without improvement, and subsequently underwent greater trochanteric bursa injection, again without improvement. On further investigation, hip radiographs were compared to post-operative images from three years prior, which revealed significant pulse generator migration inferiorly from the iliac crest towards the right greater tuberosity. It was determined that this patient’s hip pain was secondary to irritation of the gluteus medius by the pulse generator. The stimulator was explanted and patient re-started physical therapy with symptom improvement. Assessment/

Results: Improvement of pain after explantation of generator.

Discussion: Sacral neuromodulation is a widely accepted treatment strategy for various chronic pelvic pain syndromes. Common complications include lead malfunction, infection, generator malfunction, and pain at the generator implantation site. However, migration of the pulse generator has not been well documented and is a rare complication. Moreover, this case displays not only radiologic evidence of migration, but also clinical manifestations of this complication.

Conclusion: This case highlights a rare etiology of a rather common pain disorder: greater trochanteric pain syndrome. While there were multiple potential causes of greater trochanteric syndrome in this patient, including deconditioning secondary to malignancy and recent hospitalization, it is important to bring awareness of this rare complication in the setting of neuromodulation. Migration of the pulse generator, as demonstrated above, can irritate surrounding tissues resulting in painful conditions that require a comprehensive evaluation.

Level of Evidence: Level V

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PM&R Meeting Abstracts - https://pmrjabstracts.org/abstract/sacral-neuromodulation-pulse-generator-migration-leading-to-greater-trochanteric-pain-syndrome/