<p>E-mail the profs as soon as you know who they are and offer to bring medical documentation when you return. Treat it as an excused absence and apologize for being inconvenient/explain (not going into details) that it was an emergency surgery you couldn’t postpone. Having gone through weird medical situations myself it’s your profs who are usually the most helpful. If they don’t post syllabi check to see if they are listed on the course schedule listing and look up their e-mail.
Good luck!</p>