how to moderate a user's first 10 posts?

[plasticsurgery]

I've had an overwhelming spam issue the last few weeks where about 9 out of every 10 new members is a spammer. It's tedious to have to check their IP's and everything to approve them first, and even then sometimes they are still a spammer.

How can I set it so new users will have to have their first 10 posts moderated?

And the captcha doesn't work. I have it on the highest possible setting of difficulty but these spammers use programs now where they have a human manually enter the captcha information. My forum has gotten to be too much work because 90% of the time is spent fighting spam. I hate it.