Can heteropic ossification happen after surgery to have a spinal cord stimulator fitted?

Yes, but rare. Heterotopic ossification is bone formed in soft tissues from trauma -- from a bruise to an injection, to surgery of any kind. Bone forms in the healing cells that generally knit the soft tissues together -- SOFTLY! The hard bone formed can be painful, and is easily felt or seen on x-rays, as it contains calcium. Please see your doctor about this. If it doesn't bother, no treatment needed!