My wife is on her third back surgery in less than 18 months. Last being a lumbar fusion the same time you had yours.
The issue you have (as I understand it....) with topical creams is that you get less than 1/2" of penetration/absorption/effectiveness - medical professionals may correct my understanding, as needed.
She uses these patches when the soreness gets to be too much. They help some...I think Biofreeze works better on my back/neck issues.
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I'm a die hard Tiger Balm believer. The biofreeze roller is nice. I have one of the IcyHot equivalent as well