Gov. Mark Dayton's health problems have made headlines in the past.

Most recently, at age 69, he fainted at a political event on Jan. 31, 2016, and spent the night at Regions Hospital in St. Paul. His senior adviser, Bob Hume, said at the time that the governor was treated for dehydration.

That episode happened at a volunteer recognition event for state Rep. JoAnn Ward, DFL-Woodbury.

Dayton has walked with a limp for years; he and his staff have said it is because of chronic back pain. He has undergone two spinal surgeries in the past four-plus years.

The first, on Christmas Day 2012, was to fuse two vertebrae in his lower back. The surgery was to "relieve the constriction in that part of the spine, called stenosis and ... fuse a vertebrae there, which is shifting out of alignment," the governor's office said in a statement at that time. Dayton was then 65.

Dayton had a second spinal surgery on Dec. 7, 2015, when he was 68. Both surgeries were done at the Mayo Clinic. The neurosurgeon who operated on him said spinal stenosis is a common condition akin to arthritis, in which bone spurs that grow on the spine pinch nerves in the area. The condition frequently leads to weakness and instability in the legs and is often treated with surgery.

His surgeon, Dr. Jeremy Fogelson, said that before the 2012 operation, the governor was finding it difficult to stand in one place for extended periods of time.

"He required the same surgery but in a different spot," said Fogelson, adding that Dayton started to see symptoms recur a little more than a year ago. He said those symptoms have run more to weakness in the legs than problems with severe pain, which he said has allowed the governor — a recovering alcoholic — to avoid relying on pain medication.

The governor's office has always been forthcoming about Dayton's medical issues. In addition to the surgeries, he underwent a nonsurgical procedure at Mayo in 2013 in which plasma was injected into his hip to help heal a torn muscle after he fell down several steps at the governor's residence in St. Paul.