Treatment of occult radiculopathy in complex regional pain syndrome by anterior cervical discectomy and fusion following localization by [18F]fluorodeoxyglucose radioligand and PET/MRI: illustrative case.

Background: The inability to localize pain generators often results in failed back surgery syndrome (FBSS). Structural imaging can identify multiple and/or noncausative abnormalities. Molecular imaging of glucose transporters offers the opportunity to localize metabolically active sites. Using the radiotracer [18F]fluorodeoxyglucose (FDG) with positron emission tomography/magnetic resonance imaging (PET/MRI) has enabled the localization of malignant lesions and pain generators via regions of high inflammation.

Observations: A 61-year-old woman was diagnosed with complex regional pain syndrome (CRPS) and experienced right greater than left upper-extremity pain. Following PET/MRI with the FDG radioligand for GLUT, increased radiotracer uptake was seen in the right C6 nerve root and dorsal root ganglion, providing additional information to the structural MRI findings of narrowing of the right C5-6 neural foramina. Together with pain relief following a transforaminal steroid injection to the area, these results prompted the authors to perform a C5-6 anterior cervical discectomy and fusion procedure, which resulted in significant symptom relief.

Lessons: The authors present a case of worsening upper-extremity CRPS with an occult radiculopathy that improved following surgery to address a pain generator identified by FDG PET/MRI. Localization of inflammatory sites can reduce FBSS and nonspecific management of pain believed to be resulting from spinal pain generators in a wide array of chronic pain syndromes. https://thejns.org/doi/10.3171/CASE24327.