An expert disclosure to Minn. Stat. § 145.682 is not required if the negligence can be established through facts within the common knowledge of laypeople. Tousignant v. St. Louis County, 615 N.W.2d 53 (Minn. 2000). But beware: expert testimony “is necessary to support all but the most obvious medical malpractice claims.” Haile v. Sutherland, 598 N.W.2d 424, 428 (Minn.App. 1999). Only “exceptional” and “rare” medical malpractice cases fall within this limited exception. Sorenson v. St. Paul Ramsey Med. Ctr., 457 N.W.2d 188, 191 (Minn. 1990).