Which surgery is better for petit mal. my medication very unsuccessful and the side effect is memory loss?

Some comments: You likely have complex partial szs. @ age 29, and your least invasive approach is a Vagal Nerve Stimulator unit. Surgery works best if focal temporal lobe lesion identified, but some benefit if other local area of abnormality

Educate yourself: Sounds like you know little or nothing about your epilepsy. "Petit mal" is an obsolete term; hasn't been used for >20 years. Stop using it. Do you have primary generalized or partial epilepsy? Surgery is only for partial. By "surgery" do you include vagus-nerve stimulator? Surgery is only a last resort. If you're not satisfied with your treatment find an epileptilogist & educate YOURSELF too.