'It is extraordinary that doctors were able to do anything for Todd Nelson. The former US Army master sergeant's injuries were so bad the medics thought he would not survive. "I was on my 300th-plus convoy across Kabul, Afghanistan," he recalls. "We were headed home for the night when we passed next to a typical yellow and white sedan. When they saw us getting ready to pass, they flipped the switch. "The blast came in my side of the truck; I was on the passenger side. "It flipped the truck through a brick wall and put shrapnel through my right...