What is a serotonin surgery?

Hi, roxy!
I'm not sure what you mean by serotonin surgery. Do you mean serotonin syndrome? It's caused by elevated serotonin levels in your brain's metabolism that exceed acceptable levels. It can be serious but is relatively rare and readily treatable in it's early stages. This may help if that's what you mean:
https://www.drugs.com/cg/serotonin-syndrome.html

"Tramadol is widely prescribed for treating acute and chronic forms of pain. It is a weak mu-receptor opioid agonist and also increases concentrations of serotonin and noradrenaline within the limbic system of the brain."
"Venlafaxine is a serotonin-norepinephrine reuptake inhibitor, or SNRI. It helps block the reabsorption of both serotonin and norepinephrine, two chemicals in the brain that transmit nerve signals. Scientists believe maintaining proper levels of serotonin in the brain prevents depression and anxiety, and they also think boosting norepinephrine reduces neuropathic pain."

If you have other questions please post again, okay?