High concentration capsaicin kills c & a-delta nerve fibers permanently or at least long term.
This has been known for 30 years.
But capsaicin is only used in creams and patches, and not for injecting direcly into nerves, and people resort to nerve surgeries like nerve blocks, razor-damaging nerves, or rhizotomy to cut the nerve partially or fully. All of these options affect not just pain functions, but overall sensory functions.
On the other hand, capsaicin destroying c & a-delta fibers just affects pain.
So why is no one interested in capsaicin injection as an option before cutting nerves?