Frontal lobe functions: http://www.neuroskills.com/brain-injury/frontal-lobes.php
I'm not sure what you are asking in terms of side effects of removing the tumor. Are you asking about the symptoms of the tumor? Frontal lobe tumors may cause behavioral and emotional changes, impaired judgment, impaired sense of smell, memory loss, paralysis on one side of the body, reduced mental abilities, and vision loss. Removing the tumor should result in removing the symptoms created by the tumor. If you are asking about the risks of the surgery, it is the same as any surgery, e.g. risk of post op infection, etc.