Trial courts have broad discretion in granting new trials. In Johnson v. Court of Civil Appeals for the Seventh Supreme Judicial Dist. of Texas, 162 Tex. 613, 350 S.W.2d 330 (1961), the Court recognized two instances where an appellate court has overturned the grant of a new trial, to wit: when the trial court's order was wholly void as where it was not rendered in the term in which the trial was had; where the trial court has granted a new trial specifying in the written order the sole ground that the jury's answers to special issues were conflicting. Johnson, 350 S.W.2d at 331; St. Paul Mercury Ins. v. Tri-State Cattle, 628 S.W.2d 844, 845 (Tex.Civ.App.-- Amarillo 1982, writ ref'd). In Johnson v. Fourth Court of Appeals, 700 S.W.2d 916, 918 (Tex. 1985), the Court noted that a relator seeking mandamus relief based on an abuse of discretion labors under a heavy burden because mandamus will not issue to control the action of a trial court in a matter involving discretion. Id. at 917. To establish an abuse of discretion, a relator must establish, under the circumstances of the case, that the facts and law permit the trial court to make but one decision, id., and a reviewing court must conclude that the facts and circumstances of the case extinguish any discretion in the matter. Id. at 918.