He's probably lost count of the times he's done this particular operation, but neurosurgeon Hans Bakken moves as cautiously as if making his first foray into a patient's brain. With delicate and precise care, he peels away a flap of skin and removes a segment of skull. "This will give the brain room to swell," he explains.

After finishing the craniectomy, Bakken, 90BS, 95MD, 01R, 04F, leaves the operating room and makes his way through a maze of plywood corridors. Slung casually over his shoulder, a large black rifle bumps against his blue scrubs. Overhead, the heavy thump, thump, thump of approaching helicopters signals a new batch of incoming wounded to the 332nd Expeditionary Medical Group hospital at Balad Air Base in Iraq.

Medicine and war—it seems they inherently contradict each other, like life and death or surgical scrubs and guns. In fact, though, blood banks, the mass production of penicillin, air ambulances, and reconstructive surgery are just some of the life-saving developments to emerge from the smoke and rubble of battlefields and combat zones. Thanks to such improvements in medical care and treatment, many more injured soldiers and civilians survive the ordeal of war.

The death rate for U.S. troops in Iraq is about ten percent, compared to 30 percent in World War II and 24 percent in Vietnam. Balad officials estimate that patients who arrive at their hospital alive have "about a 96 percent chance of leaving alive."

Even in the last few years, military medical care—from "buddy aid," when troops give basic treatment to a wounded comrade, to field hospitals—has evolved significantly. First aid kits now include devices such as tourniquets that soldiers can apply with one hand or bandages made with an extract from shrimp cells that staunches bleeding within seconds.

Mobile Army Surgical Hospital (MASH) units, innovations from the Korean War, have literally advanced. In previous wars, most troops died before they even reached a field hospital. While medical experts talk of the "Golden Hour"—the critical time to successfully stabilize and treat serious trauma—the surgical teams in Korea stayed several miles from the front. Knowing that every minute, every second counts when a soldier's blood is soaking the ground, their contemporaries travel with the troops. Modern forward surgical units can be unpacked from the back of a Humvee and set up within an hour to provide all the resources and equipment for diagnosis, anesthesia, surgery, and other high-tech treatments.

In previous conflicts, surgeons would usually perform all the necessary steps to treat a wound, but care in Iraq may take place in stages: do what's necessary to stabilize the patient and then send the injured on to the next experts. Vacuum-sealed plastic can keep open wounds covered and sterile until the patient is transported to Balad or other facilities.

Like an episode of ER on fast-forward, a soldier's journey from the battlefield to the operating table and then home can happen in a blur of hours. In Vietnam, wounded soldiers often spent six or eight weeks receiving treatment at military hospitals before returning home for further care; in Iraq, they're usually shipped off within 48 hours to facilities such as Landstuhl Regional Medical Center in Germany or Walter Reed Army Medical Center in Washington, DC. Dozens of patients—even critically ill ones hooked up to ventilators—can travel on specially equipped planes that have been transformed into flying intensive care units.

Tents in the desert are a far cry from what he was used to as a neurosurgeon in Tacoma, Washington, but Bakken is part of a medical team at Balad that provides a remarkably sophisticated level of care. The steel-walled OR in which he performs brain surgery is one of three such rooms on the base, a heavily fortified oasis in the Iraq desert about 50 miles north of Baghdad.

Sprawling over 37,000 square feet, Balad is comparable to America's best hospitals. The connected tents house an intensive care unit, laboratories, X-ray machines, CAT scanners, and much more. (Balad lacks only the facilities to provide MRIs and renal replacement therapy.) Some 300 medical personnel represent a spectrum of specialties from trauma and orthopedics to cardiothoracic and oral maxillofacial surgery.

Balad also offers something absent from most civilian hospitals: a constant stream of patients with complex and rare injuries. Over and over again, staff get to practice and hone their skills. While practice may not make perfect, in Iraq it can mean the difference between life and death.

After countless evacuations in which they fine-tune the routine, combat medics shave precious minutes off the time it takes to rush a wounded soldier from the field onto the operating table. Regularly confronted with extreme injuries inflicted by bomb blasts and shrapnel, surgeons dramatically improve their abilities to salvage mangled flesh and repair shattered bones. "I've never seen this level of trauma before," admits Bakken, who left private practice in 2005 to join the Army because he "wanted to help the troops in Iraq."

Susan Lawrence, UI associate professor of history and a faculty member in the Program for Biomedical Ethics and Medical Humanities, says that, while not every branch of medicine benefits from war-gained knowledge, surgery is an exception. "Since the Napoleonic wars, conflict has been seen as an exciting time for surgery," she says. "In that war, surgeons wrote about what an amazing experience it was to practice and improve their skills."

Reconstructive surgery can trace its roots directly to the horror-filled trenches of the First World War. Faced with an unprecedented level of injuries among soldiers who had been shot, bombed, and gassed, surgeons had to figure out how to reconstruct bone, graft tissue, and treat burns and scars.

Such hard-won expertise and knowledge can have far-reaching effects off the battlefield. In the aftermath of the Spanish-American War, Army doctor Walter Reed revolutionized the treatment for yellow fever by proving that it was transmitted by mosquitoes. Reconstructive surgery for scarred soldiers grew into plastic surgery for people wishing to improve their appearance. Helicopters that transported the wounded in Korea and Vietnam made an easy transition to civilian life, where they've improved quick access to medical care in American cities and rural areas. Along similar lines, the military planes that handle large-scale medical evacuations in Iraq could also prove invaluable in peacetime emergencies, when terrorists or natural disasters strike.

Sometimes, war's influence on civilian health is less obvious or immediate. During the draft for World War II, many young men failed the physical examinations because of correctible and preventable health problems, such as rickets, malnutrition, and work-related injuries. Astounded and horrified, the public supported campaigns to provide better nutrition and health care to the working class and poor.

In this current conflict, battle-tested techniques and knowledge may end up in medical textbooks or be put to use in stateside hospitals. Drafted into the ongoing fight to save the lives of trauma patients, new products such as the shrimp cell bandage are finding their way into American ambulances and hospitals. Civilian amputees' lives are improved by advanced prosthetic devices originally designed for soldiers who sacrificed limbs to landmines or improvised explosive devices (IEDs).

As of June, some 19,000 U.S. military personnel had been wounded since the Iraqi conflict began in March 2003. Many of those troops, as well as Iraqi citizens and insurgents, pass through the hospital at Balad, where doctors treat more than 650 ER patients and perform 450 surgeries a month. Earlier this year, Bakken operated on seriously injured ABC News anchorman Bob Woodruff and cameraman Doug Vogt.

Just 37 minutes after the blast from an IED hit the armed vehicle from which they were reporting in Baghdad, Woodruff and Vogt arrived at Balad by a medical evacuation helicopter. Thanks to the expert care they received, they were soon able to be transferred to Germany and then back home, where they're recovering.

Whether his patients are high-profile media representatives, American soldiers, or local children, Bakken knows his skills are desperately needed in Iraq. That's why he recently signed up for another tour of duty with the Army. As a helicopter whisks his next set of patients into the camp, Bakken follows the familiar route through the makeshift corridors.

The neurosurgeon leans his rifle against the wall of the OR. Then, armed with his medical expertise and knowledge, he begins another military operation.