Have you ever heard of an X-stopper for spinal stenosis. My father called and said he's having surgery Monday to put an X-stopper in his spine. I went on-line but couldn't find anything to explain this.
It sounds like he may be referring to the X Stop device. This small implant is made of titanium. It fits between the spinous processes of two vertebral bones. The spinous process is the bony knob you feel along the back of your spine.

The X Stop holds the vertebra in a slightly flexed position. It keeps the spine from extending at that level. Flexion opens up the spinal canal, the area where the spinal cord or spinal nerves are located. Extension closes down this space.

With spinal stenosis, there is a narrowing of the spinal canal from a variety of age-related changes in the spine. Anything that narrows the spinal canal puts pressure on the nerve tissue.

Since a flexed position of the spine causes painful symptoms to increase, patients end up stooped over in an attempt to relieve the pain. They are unable to comfortably stand up straight. The X Stop puts the affected spinal level in the flexed position and holds it there. The patient can stand up freely without fear of symptoms coming on or getting worse. And it helps them avoid the stooped that is so characteristic of someone with spinal stenosis.