One of the biggest challenges soldiers face when wounded on the battlefield is infection. Explosives create a high-energy injury that can leave a wound open to the elements (dirt, debris). If the bone is broken and the skin laid open, the wound is at risk for tissue contamination.
In this article, surgeons from Walter Reed Army Medical Center discuss the diagnosis and medical/surgical management of chronic infection. In particular, the most common bone infection from severe war injuries called osteomyelitis is the main focus of their attention.
Treatment is usually débridement (irrigating and cleaning out the wound) and reconstruction. Surgeons have learned over the years that bacteria have a way of coating the bone and wound with a special covering called a biofilm.
It’s this thin layer of microorganisms that cling to the surface of the bone that must be cleaned out and removed. Any microscopic groups or colonies of bacteria left behind will just keep reproducing causing recurrent or chronic (ongoing) infection.
Scientists have shown that a single bacteria cell can make billions more like itself in a 24-hour period of time. As a result of this bacterial reproduction rate, debridement may have to be done more than once.
Antibiotics (medical treatment) help but the overuse of antibiotics has led to some pretty resistant bacteria. Instead of taking oral antibiotics or having antibiotics delivered directly through the blood stream via an IV (intravenous) method, it is better to put antibiotics directly inside the wound (local delivery).
This can be done using special antibiotic beads, sponges soaked in an antibiotic fluid, or antibiotic coated spacers. Any implant devices (rods, screws, metal plates, joint replacements) must be coated with an antibiotic as well.
Research is ongoing to find better, faster ways of delivering antibiotics to the affected tissue. The goal is to find a balance between the right amount of antibiotic to get rid of the bacteria but not so much the local tissue reaches toxic levels that prevent wound healing.
On the surgical side, surgery or a series of surgeries may be needed to restore the patient to full function again. This can take months to years to complete. During reconstructive surgery, the surgeon must put everything back together (bone, muscle, other soft tissues) and find enough skin to cover and close everything up.
Various reconstructive techniques include bone grafting, limb shortening, skin or bone flaps, and internal or external fixation are common. The goal is first, to preserve the limb and second, to maintain as much limb length as possible to match the other side.
Treatment does depend on an accurate diagnosis and gathering as much information as possible about the amount of bone loss, edema or swelling, and the presence of bone abscess.
X-rays, MRIs, and other imaging studies are very helpful. Blood tests must be done to assess the amount of immune system response and the presence of bacteria or fungi in the tissues or fluids.
The authors conclude by exploring future research directions in the treatment of chronic combat-related bone infection of the limbs. Efforts to understand how bacteria signal one another and grow will provide more specific ways to stop their reproductive cycle.
Right now, scientists are just in the experimental stage with more theories than solutions. They expect it may be quite some time before any major breakthroughs change the way chronic osteomyelitis (bone infection) is managed.