Surgeons discuss challenges, advances in combat orthopaedics
By Peter Pollack
A group of orthopaedic surgeons experienced in combat care spoke to a packed auditorium yesterday and presented the continuing challenges and improvements in the area of orthopaedic trauma care on the battlefield.
The Orthopaedic War Injuries from Combat Casualty Care to Definitive Treatment: A Current Review of the Basic Science, Clinical Advances and Research Opportunities symposium was followed by a media briefing devoted to the same topic.
The symposium was co-moderated by Capt. Dana.C. Covey, MD, of the U.S. Navy Medical Corps and Chair of the Department of Orthopaedic Surgery at Naval Medical Center, San Diego, and Roy K. Aaron, MD, Director of the Veterans Administration Center for Restorative and Regenerative Medicine and the Brown Program for Recovery from Trauma. Other speakers included Jason H. Calhoun, MD; Thomas A. Einhorn, MD; Lt. Cmdr. H. Michael Frisch, MD; Col. Roman Hayda, MD, MC; L. Scott Levin, MD, FACS; Cmdr. Michael T. Mazurek, MD; Col. Elisha T. Powell IV, MD; Edward Schwarz, PhD; and Joseph C. Wenke, PhD.
A different type of injury
Although much of the knowledge gained through civilian orthopaedics can be applied to over into combat situations, much of it cannot. Combat injuries often involve high velocity shells, which are likely to result in a very different type of injury compared to that of the lower velocity bullet wounds sometimes seen in civilian trauma centers. Additionally, injury from explosives is much more common. As Dr. Hayda pointed out, these are issues that civilian physicians need to be aware of, particularly in the event of a terrorist attack. More than 80 percent of injuries from terrorist attacks are due to blasts caused by the inexpensive yet devastating nature of explosive devices.
With that in mind, Dr. Hayda opened the symposium with an explanation of blast physics and its effect on the human body. In an explosion, air pressure rises precipitously outward in a shock wave due to the rapid conversion of liquids and/or solids into gas. As the shock wave passes, the pressure quickly drops to less than normal, then rises and stabilizes again. The period of low pressure results in a reverse “wind” that can suck debris backward into the blast area, resulting in additional injury.
In an open air event, the force of an explosion dissipates very quickly on a geometric scale, concentrating the most serious effects near ground zero. In comparison, a blast in an enclosed space such as a building will result in resonating shock waves that can complicate both injury and triage. Lower-energy explosions tend to result in more debris damage, while higher-energy explosions are likely to result in greater initial shock damage.
Because of the complex series of factors that may play out in an explosion, Dr. Hayda stressed the importance of exercising care and not taking such injuries at face value.
Dr. Hayda separated blast injuries into four levels. The primary blast injury is caused by stress, shock, and shear waves. In this level, any air-bearing organs such as lungs or the colon can be compressed quickly, resulting in severe tissue damage. From an orthopaedic perspective, traumatic amputation is also likely to be an effect of primary blast injury.
The secondary blast injury is caused by debris moving through the area of the blast. Tertiary blast injury is caused when a person is thrown into something such as a wall. Finally, quaternary blast injury consists of multidimensional injuries caused by other factors related to the blast, such as burns from a resulting fireball.
Combat injury issues through the years
Dr. Calhoun began his briefing with a review of how combat orthopaedic surgical techniques have changed over the past 150 years. During the U.S. Civil War, amputation was a primary means of controlling infection, and antiseptic techniques were crude or nonexistent. Gangrene was a common complication, and many soldiers didn’t survive an amputation.
By World War I, delayed primary closure had replaced amputation in many cases, and mortality rates from extremity wounds decreased, even though the battlegrounds in that war were breeding grounds for infection.
During World War II, surgical debridement had become more common, and large-scale production of penicillin reduced mortality rates further. Still, many physicians considered amputation to be a first-choice alternative to infection, and stories abounded of injured soldiers being told by their nurses to “ask for the shot” when presented with amputation as an option.
In Korea and Viet Nam, soldiers could be more easily evacuated to more capable and sanitary facilities far behind the battlefield. This trend is continuing, and today, a severely injured soldier in Afghanistan or Iraq could be in a hospital in the San Antonio (Texas) Military Medical Center within 48 hours, according to Dr. Hayda.
Even with advances in transportation and sanitation, infection remains a primary issue. Dr. Calhoun recommended that surgical antimicrobial prophylaxis be initiated just before an operation begins and continued for no longer than 24 hours. He points out that multidrug resistant organisms and strains of Acinetobacter baumannii are cause for concern, and new antibiotic strategies may need to be developed. He also stated that recent evidence shows that Acinetobacter itself may turn out to be more of a marker than an issue of its own.
In the future, Dr. Calhoun expects to see more studies done on the choice and timing of introducing antibiotic agents in battlefield injuries. He opined that clinical research on combat wounds may show that antibiotics introduced at the time of injury (incision) is effective, and predicted that more work will be done in the area of genetics, helping physicians to identify and treat resistant strains of bacteria.
Dr. Einhorn sees even more impressive progress in the future of combat orthopaedics, and referred to promising work being done in stem cell research—harvesting and implanting such cells with the goal of regenerating bone marrow. He also pointed to small but encouraging studies that made use of recombinant proteins to assist in regrowing bone. Although the technology is early in its experimental cycle and the doses required are high, the preliminary results are enough to justify further research.
The current state of the art
Dr. Mazurek addressed current battlefield models, focusing on what he called the “second hit”—the effect of initial treatment on a patient after the wound has occurred. To that end, he discussed stabilization goals for wounded soldiers, including hemorrhage control, rapid control of a life-threatening injury, and steps necessary to set up the wounded soldier for a positive long-term outcome.
He stressed a change in approach beginning in the 1990s, toward what he called damage-control orthopaedics (DCO). In the past, the medical response to a battlefield injury usually attempted to address every possible extent of a wounded soldier’s injuries, resulting in many hours on the operating table and extreme stress to the patient’s condition. DCO shifts the focus to the essential care that a patient needs for optimized outcome. The patient can then be sent to the intensive care unit, and when stabilized, is returned to the operating room for more extensive and permanent surgery.
Dr. Mazurek pointed out that DCO does not mean doing the absolute minimum on the battlefield. Rather, the patient’s needs are assessed and his or her treatment is handled in a manner likely to produce the highest quality outcome.
In amputation and reconstruction situations, said Dr. Levin, “never throw anything away.” Taking a cue from those in the plastic surgery field, he suggested that it is a good idea to preserve limbs rather than discarding them, with the idea that even a heavily damaged body part may provide material for certain types of reconstruction.
As the panelists noted, soldiers wounded in Viet Nam had a 75 percent survival rate. That rate has risen to 90 percent in the wars in Afghanistan and Iraq, yet despite all of the advances in medical technology, soldiers continue to return from the battlefield with injuries that cannot be adequately repaired. Still, the state of the art continues to improve, and there is a strong bond between orthopaedic surgeons working along the lines of combat and those in civilian life.
Combat conditions rarely lend themselves to clinical study, so despite the difference between the types of trauma commonly encountered, research being done in civilian fields is often carried over into the military. Similarly, much as the space program has contributed technology to the lives of those on earth, the extreme environments of the battlefield contribute to the field of orthopaedics in a way that clinical studies cannot. Although war is an unfortunate truth of modern life, both civilian and military orthopaedic surgeons are working hard to take the lessons learned and turn them into a better future.