be careful. the above guy has some true statements, but misses a few things too.
1. i believe there are more IMG's than DO's in traditional MD residency programs.
2. DO's have their own residencies that MD's cannot touch. this is not true for IMG (good point from above poster)
3. IMG's may have difficulty matching into many fields, not just neurosurgery, in the United States. DO you'll be guaranteed to match somewhere in something in USA if this is where you're planning to practice.
the safer bet is DO. but if you are gunning for a top residency training, then IMG may be a better choice. I don't want to sound harsh or overly critical, but if you were unable to get into an MD school for scholarly reasons, then you may be better of going the DO route. work hard and realistically you can expect to get into a DO residency and still become a neurosurgeon.
good luck