How do you treat postherpetic neuralgia not adequately responding to oral neuropathic pain medications, lidocaine, and capsaicin?

By the Q, it is assumed all PO meds and topicals have failed. There are other compounding options but none with high-quality EBM support (i.e., gabapentin, TCA, camphor/menthol, pregabalin, ketamine, NSAIDs, CBZ…). Therefore, if PO and topical treatments fail, only procedures remain.

1. IV therapy - l...