Whose Factual Analysis Should Trump?

According to Paul Wolfson, the Senate's recent passage of a bill that bans partial-birth abortions may be unconstitutional because it directly challenges the Supreme Court's factual findings on a PBA procedure known as D&X (dilation and extraction). In Stenberg v. Carhart the Court found that because D&X procedures tend to be the least risky on a woman's "health", banning it imposed an "undue burden" upon a woman's right to obtain a "safe" abortion. For Wolfson, Congress is unconstitutionally contradicting the Supreme Court's authority by justifying a ban on D&X procedures upon the factual premise that such procedures are never necessary to preserve the health of a woman.

Maybe I missed it, but I don't know where the Court ever addressed the issue of whether D&X procedures were ever necessary. (Clarification: It seems to me they presumed it without factual basis). Moreover, I don't see where Congress is saying that D&X isn't the least risky PBA procedure on a woman's "health". It may very well be. However, most credible medical evidence supports the notion that D&X is unnecessary. As such, Wolfson's article seems to be nothing more than a veiled rationalization for upholding the legalized butchering of innocent human lives.