[pak]

Well, for starters, it's hard to get 200 people who might be eligible for life-preserving surgery to volunteer to possibly get a sham procedure for the exclusive benefit of othewars; not to mention build a team of surgeons, hospitals, etc. willing to do the trial; and someone to pay for millions of dollars in treatment and administrative costs. Clinical trials involving surgery, especially with sham procedures as a proper control, are exceedingly rare in the US for these reasons. (this is discussed in the OP itself.)