Middle name and Отчество are different things.

It's possible that to issue a birth certificate they require an отчество, but probably not necessary for passport (person can choose any name, even change names when applying for a passport). I know an American citizen who married a Russian woman citizen, they adopted an infant, and they required the отчество for the birth certificate, even though he was not the biological father. So they used his American name for отчество (though there's no Russian equivalent for his Anglo-Saxon name, they just added -ович to the name, and it was OK for everyone). So in such cases it looks like a legal formality (at least, in today's legislation). It's probably possible to make almost any name take a Russian patronymic ending, or find a close equivalent.