I had a stroke five years ago. I had been taking neurontin (unsuccessfully) for pain. My doctor prescribed Tegritol. It helped the pain somewhat, but brought on impotence. Question: is that a fair trade? In my case, absolutely not! I'm going to gradually get off the tegritol and seek doctor advice for a substitute.
Stroker
I did an extensive literature search to look at both anitepileptics and impotence as well as brain tumors, frontal lobe lesions and impotence. Here's what I found:
1.you're right about the tegretol, that's well known to cause sexual dysfunction. But in one case series, lamictal seemed to improve impotence, desire, and orgasm in men when they switched over. I found nothing on lamictal causing impotence, but that doesn't mean it can't. I would stick with it for now and do NOT reduce it on your own. The complications from seizures certainly outweigh the possible benefits that you are looking for. Talk to your docs about adjusting the meds first.
2. The erection center in men still hasn't been clearly defined yet, but so far they think it's in the brainstem or spinal cord rather than the brain hemispheres themselves. This probably means that the location of the tumor and resection doesn't directly affect the erections. However, if you are left handed, then your dominant side may be the right side which controls speech, writing, calculations, analytical thinking while the nondominant (in your case left) would be the emotional side. So the impotence could represent decreased desire or emotional aspect of sexual intercourse, rather than a mechanical problem.
Just a theory. Best of luck.