All that changed on Monday when victims of the bombings at the Boston Marathon arrived.
“We’ve seen similar injuries, but never of this magnitude,” Dr. Weaver said. “This is completely different.” The military experience, he added, “has been phenomenally helpful.”
But doctors said they had also prepared for a disaster, with regular drills. At Massachusetts General Hospital, for example, part of the emergency department’s disaster preparedness included bins of special wristbands to identify disaster patients. “We can’t sit there and write names of patients” on wristbands, said Dr. R. Malcolm Smith, chief of the medical center’s orthopedic trauma service. Instead, medical personnel in the emergency department slapped wristbands on patients that identified them with special disaster numbers. The bands said simply, Disaster Victim 001, Disaster Victim 002, and so on. Patients’ names were added later.       
It turns out to be an art — and a delicate balancing act — to treat people with blast injuries that can pulverize muscle and rip blood vessels, that can drive pieces of metal into soft flesh and shatter bones. Trauma surgeons call it damage control, and say the military experience showed how important it is. The idea is not to try to solve all of a patient’s medical problems at once, but instead to deal with the urgent and life-threatening ones immediately. Patients often have to return to the operating room again and again as their injuries are successively repaired. The first priority for those who were severely injured was to prevent them from dying, often from bleeding to death. Many had tourniquets on their legs when they arrived at the hospitals. But that was just a temporary measure to slow the bleeding. They needed immediate surgery to get their bleeding under control and prevent muscles and nerves from dying for lack of blood.  That requires a vascular surgeon to repair the torn blood vessels and restore blood to legs and feet that may no longer have a blood supply. To do those repairs, surgeons often sew in part of a vein from the other leg, if it is uninjured, or from an arm. Or they use a synthetic tube. Meanwhile, an orthopedic surgeon must stabilize a bone that might be flopping because it is fractured in several places. Surgeons do that with a temporary solution — they drill into the bone from outside the leg and attach pins that they screw into a metal bar also outside the leg. Plastic surgeons clean the wound. In this case, blast victims had BBs or nails or debris embedded in their legs and feet. Everything the surgeons took out of the wounds was placed in plastic bags for the F.B.I., said Dr. Samuel J. Lin, a plastic surgeon at Beth Israel Deaconess Medical Center who helped care for blast victims. “The crime scene extends to the hospital,” Dr. Lin said.       
Patients then are sent back to intensive care or their hospital rooms for the next few days while doctors wait to assess the damage to muscles and nerves and blood vessels. “With a blast injury in particular, we can’t always be sure how widespread the soft tissue injury is,” Dr. Smith said. Badly injured, dead tissue needs to be removed to avoid infection. And that may mean repeated visits to the operating room. But there are no other options. “If we leave dead tissue in place, it gets infected,” Dr. Smith said. And if the soft tissue dies, a leg might have to be amputated. The next priority is repairing soft tissue — muscle and nerves and skin. “Everything depends on soft tissue repair,” Dr. Smith said. “If you don’t have healthy soft tissue, bone will not survive.” That means that plastic surgeons have to close what may be gaping wounds.       
Wound healing has been revolutionized by a vacuum device, Dr. Lin said. Patients with large wounds used to just be bandaged and have their dressings changed several times a day. Now, doctors put a black sponge over the wound, cover it with a thin sheet of plastic wrap, and attach it to a vacuum hose. Wounds heal faster, and patients are in less pain.
A big advance, Dr. Weaver said, whose value was proved by the military, is taking tissue from smaller areas to close a large open wound. Surgeons used to take big chunks of muscle along with blood vessels from a person’s abdomen or back and move it to the wound to repair the injury.
Now, he said, they take much smaller pieces of tissue from places like the forearm or thigh. It means a smaller surgery and fewer complications.
But uncertainty about the fate of soft tissue surrounding a wound can remain for days after a repair. If it dies, and if further attempts to trim the dead tissue and repair the wound fail, patients face amputations.
When it comes time to repair shattered bones, orthopedists make use of stabilizing metal plates developed over the last decade or so that are vast improvements over earlier ones, Dr. Weaver said. They still have to attach the plates directly to the bone, where they will remain for the rest of the patient’s life. But the new plates are designed to fit exactly against the shape of the bone, making the bone more stable.
“To restore the function of a knee or ankle, you have to put the pieces of bone together like a jigsaw puzzle,” Dr. Weaver said.
The military also greatly improved reconstruction, prosthetics, and rehabilitation for those who need amputations. Of course an amputation is still devastating, but now, with the improved prosthetics, many patients can walk, run and enjoy essentially normal lives, Dr. Weaver said.
For many of the blast victims, the path to recovery will be long and arduous, with weeks in the hospital and rehabilitation lasting as long as a year. While bones can heal, patients may be left with stiffness from torn muscles, bad scars from the operations, and, if a joint was severely damaged, arthritis in it.
The victims, Dr. Smith said, were mostly younger people who were watching the race. The blasts went off behind them, ripping the backs of their legs.
Some know what they are facing in the months to come, Dr. Weaver said. But others, he added, do not. “Many who are critically ill in intensive care are still waking up,” he said.