A Missouri death row inmate who lost substantial brain tissue during a surgery plans to ask the U.S. Supreme Court to review his case, saying his planned execution by lethal injection could subject him to severe pain.

The Columbia Daily Tribune reported Thursday that Ernest Lee Johnson plans to argue that the loss of brain tissue could mean he has seizures and severe pain in reaction to Missouri’s execution drug.

Johnson was sentenced to death for killing three convenience store workers during a Columbia robbery in 1994.

Johnson’s appeal is moving through lower courts. But Johnson’s attorneys plan to ask the U.S. Supreme Court to intervene because the high court is currently considering a similar case of another Missouri death row inmate with a rare medical condition that causes blood-filled tumors.

Both argue complications with their conditions and the execution drug could lead to cruel and unusual punishment.