During the decade since terrorists attacked the World Trade Centers in New York City and the Pentagon in Washington, D.C., more than 32,000 service members have been wounded in action as part of Operations Enduring Freedom (OEF) and Iraqi Freedom (OIF). Although Dec. 15, 2011, marked the end of the military mission in Iraq and current operations in Afghanistan are winding down, the medical mission to treat and rehabilitate those wounded continues.
On Jan. 18, 2012, military and civilian orthopaedic surgeons, researchers, government representatives, and other medical specialists gathered in Washington, D.C., to evaluate the progress made in the treatment of extremity war injuries (EWI) and to examine the ongoing clinical and rehabilitative challenges facing orthopaedic surgeons and their patients.
“A Decade at War: Evolution of Orthopaedic Combat Casualty Care,” the seventh Extremity War Injuries Symposium, was hosted by the AAOS, the Orthopaedic Trauma Association (OTA), the Society of Military Orthopaedic Surgeons (SOMOS), and the Orthopaedic Research Society (ORS).
The changing nature of injuries
The magnitude of combat blast injuries in Afghanistan has intensified due to the increased number of missions conducted on foot. In Iraq, soldiers were more likely to be inside armored vehicles when hit by an improvised explosive device (IED). But the emphasis on operations conducted on foot in Afghanistan has resulted in an influx of Dismounted Complex Battle Injuries (DCBI).
DCBIs represent a constellation of polytraumatic injuries including bilateral high transfemoral amputations, open pelvic fractures, and severe upper extremity injuries. Medical and technologic advancements have enabled more wounded service members to survive DCBIs despite their complexity. According to data released by the Pentagon, American fatalities in Afghanistan decreased by 11 percent from 2008 to 2009.
The efficacy of the tourniquet
The increasing survival rate of soldiers with DCBIs is due in part to the progress made in hemorrhage control and medical evacuation modalities. A decade ago, isolated limb exsanguination, or bleeding out, was the most common cause of preventable death on the battlefield. Concerns about muscle and tissue damage meant that tourniquets were often used only as a last resort.
“Survival after severe battlefield injury is immediately dependent on prompt hemorrhage control and rapid medical evacuation (MEDEVAC),” reported Capt. Dana C. Covey, MD, of the department of orthopaedic surgery at Naval Medical Center, San Diego. “When this process is fast and efficient, it facilitates lifesaving surgery.”
Studies have shown a systematic change in hemorrhage control methods during the decade. A 2009 study conducted by Col. John F. Kragh Jr, MD, examined survival rates of more than 2,800 military and civilian personnel with major limb trauma admitted to a combat support hospital. Of the 232 patients who had tourniquets applied (either in the field or in the emergency department, the survival rate was 90 percent in the absence of shock.
Because of these and similar findings, service members are now required to carry a combat application tourniquet. “The decision to use a field tourniquet is made by a battle buddy, medic, or corpsman at the time and point of injury,” said Capt. Covey, who noted that approximately 2,000 lives have been saved as a result of this during operations in Iraq and Afghanistan.
Care in the air
Prompt evacuation of the wounded and proficient “care in the air” are also critical components of the unprecedented rates of survival in current conflicts. At the start of the OEF/OIF deployments, the safety of air transport and wound care in flight was challenging. Concerns arose about the development of compartment syndrome and the failure of wound management devices, such as negative pressure wound therapy (NPWT), in flight.
Refuting the axiom that “NPWT during MEDEVAC is bad,” Andrew N. Pollak, MD, chief of orthopaedic trauma at the R. Adams Cowley Shock Trauma Center (Md.), reported on a study on the feasibility and safety of NPWT in flight. The retrospective review of 218 patients (298 wounds) treated with NPWT during aeromedical evacuation from Iraq or Afghanistan to Landstuhl Regional Medical Center (Germany) found that complications occurred at 14 percent of wound sites in 19 percent of patients. “The overwhelming majority were minor, and in no cases was the failure of NPWT attributed to the complications,” said Dr. Pollak.
A second study by Lt. Col. Raymond Fang, MD, and colleagues reported no significant in-flight complications from NPWT in 30 patients with 41 wounds. “The information from these studies has led to a change in practice,” said Dr. Pollak. “Most severe wounds are now being treated with NPWT during medical evacuation.”
Andrew H. Schmidt, MD, director of clinical research at Hennepin County Medical Center (Minn.), presented data collected from three Department of Defense-funded studies evaluating the effects of altitude on muscle compartments in animal models. According to Dr. Schmidt, these investigations revealed that although subtle differences in muscle physiology do occur at altitude, “these are not sufficient to consider that altitude causes compartment syndrome.”
Ongoing surgical challenges
Although advances in hemorrhage control and evacuation have improved soldiers’ chances for survival after sustaining severe battlefield injuries, surgical care of DCBI is challenging.
George F. Muschler, MD, director, orthopaedic research and clinical tissue engineering at the Cleveland Clinic Foundation, noted that one of the most demanding surgical challenges facing orthopaedic trauma surgeons is the treatment of large segmental bone defects resulting from DCBI. These defects can be as large as 20 cm and are often complicated by regional soft-tissue loss, reduced vascularity, regional scarring, and infection.
Dr. Muschler provided an overview of data from the Armed Forces Institute of Regenerative Medicine (AFIRM) on the efficacy of therapies for repairing bone defects, including the effectiveness of different bone morphogenetic protein (BMP) delivery systems. According to Dr. Muschler, the combination of a perforated mesh tube, hydrogel, and BMP yielded a higher rate of bone regeneration in rat femurs when compared to either a collagen scaffold and BMP or a hydrogel scaffold and BMP.
Dr. Muschler also described a study performed by the U.S. Army Institute of Surgical Research on the benefits of dual-purpose bone grafts, which deliver BMP and antibiotics at the same time. This study showed that the simultaneous delivery of BMP and antibiotics increased new bone formation in critical size femoral defects in rats by as much as three times and reduced infection when compared to delivering BMP alone. AFIRM research also confirmed mineralized cancellous allograft as the “gold standard” of bone graft substitutes.
According to Dr. Muschler, new animal models are now being developed because research in existing models has reached a “ceiling effect.” Dr. Muschler said, “Advanced animal models will enable collaborating teams to objectively assess emerging technologies under conditions that more closely match actual clinical application.”
Rehabilitation and reintegration
As of January 2012, more than 1,400 service members required major limb amputations due to wounds sustained during military operations in Iraq and Afghanistan. Nearly one in four service members incurred the loss of multiple limbs. The increase in on-the-ground operations and exposure to IEDs has resulted in an increase in the number of bilateral transfemoral (BTF) amputations.
These injuries present unique challenges for rehabilitation teams, according to Col. Paul Stoneman, PR, PhD, head of physical therapy services at Walter Reed National Military Medical Center. Advances in prostheses and rehabilitation techniques, however, have made ambulation increasingly more achievable.
Col. Stoneman illustrated the benefits of the powered knee, a new prosthetic technology that may allow BTF amputees to start ambulating sooner. Currently, BTF amputees begin their rehabilitation using a “shortie,” a prosthetic device that does not include a knee. Prostheses are then lengthened and knee components are added as the patient progresses. However, because the “shortie” does not have a knee component, patients may develop abnormal gaits that are difficult to correct.
Advancements in research may allow BTF amputees to bypass the “shortie” stage. According to Col. Stoneman, this could accelerate community integration by allowing patients to obtain the early endurance and balance skills necessary to develop a more natural and functional gait.
Amputations of the upper extremity are also common in soldiers returning from Iraq and Afghanistan. More than 20 percent of OEF/OIF amputees have lost an upper limb. Current mechanical and electrical upper limb prostheses are often hard to control and do not provide a patient with the dexterity of a natural hand. A new surgical technique developed by Todd Kuiken, MD, PhD, and colleagues at the Rehabilitation Institute of Chicago Center for Bionic Medicine seeks to resolve some of these challenges through targeted muscle reinnervation (TMR) and electromyographic (EMG) control.
According to Dr. Kuiken, in TMR the residual nerves of an amputated limb are transferred to a spared muscle near the limb. The nerves grow into this muscle and the surface EMG can be used to control a device. “When an amputee thinks ‘close hand,’ the muscle will contract and the myolectric signal can be used to close a powered hand,” said Dr. Kuiken. “Because the patient is using the appropriate neural pathways, control is easy, intuitive, and fast.”
Dr. Kuiken also described a process called targeted sensory reinnervation (TSR) in which sensory nerves are transferred to residual nerves to restore sensory feelings to a patient. “TSR can provide a pathway for true sensory feedback of touch, pressure, and thermal feedback,” he said. Patients who have undergone targeted reinnervation surgery have shown “marked improvements” in agility, grip, and control of their prostheses.
Defining future priorities
Significant scientific advancements have been made in the acute, reconstructive, and rehabilitative care of wounded warriors. However, continued research is needed to close the critical knowledge gaps that still exist. The EWI VII symposium aimed to review existing knowledge on the treatment of traumatic extremity injuries and define ongoing research priorities.
Col. James Ficke, MD, chair of the EWI project team, discussed improvements regarding patient evacuation, hemorrhage control, segmental bone defect technologies, amputee rehabilitation, and data collection. Research is still needed in the following areas:
- the prevention and treatment of heterotopic ossification
- the prevalence of antibiotic-resistant bacteria
- the identification of risk factors for long-term complications in amputees and limb salvage patients
- the investigation into the causes and mediators of posttraumatic arthritis
These priorities will be relayed to Congress in upcoming advocacy efforts conducted by the American Association of Orthopaedic Surgeons (AAOS).
Since the inaugural EWI symposium in 2006, great strides have been made in communicating the critical need for advanced musculoskeletal trauma research to Congress. Before 2006, the U.S. government was not investing any money in research directed at improving care for extremity war injuries. Due to efforts of the AAOS and its specialty partners, EWI research is currently funded at $30 million.
Rep. Jason Altmire (D-Pa.), keynote speaker at the symposium, stressed that the AAOS and its allies must continue to promote the need for additional investments in research. “We must continue to work together to convince Congress that this investment is critical to improving the care of patients with both combat- and noncombat-related injuries,” he said.
Battlefield injuries have similar characteristics to civilian traumatic injuries resulting from motorcycle crashes, natural disasters, and terrorist attacks. “What we learn about the care of military trauma injuries can be translated to the civilian environment, thereby improving the quality of trauma care that civilian surgeons can offer to their patients,” said Dr. Pollak.
Advocacy efforts by the AAOS and its partner organizations aim to include EWI research as a line item in the federal budget instead of as a yearly appropriation. “We believe that the federal government needs to create programs within the National Institutes of Health, the Department of Defense, and other agencies that will allow investigators to continue to look for better, more cost-effective ways to take care of severe injuries,” said Dr. Pollak.
Madeleine Lovette is the communications specialist in the AAOS office of government relations; she can be reached at email@example.com