Nigerian surgeons report new, simpler technique for treating chronic osteomyelitis

Chronic osteomyelitis, a progressive infection in bone, can occur after treatment for acute osteomyelitis, a new infection in bone that usually results from injury. 

KM Onuoha, AO Bassey, O Omotola and A Adedapo, a team of surgeons at Cedarcrest Hospitals in Abuja, Nigeria, reported on a new technique for treating acute osteomyelitis that helps prevent its developing into a chronic bone infection. Their case study of a 7-year old girl with osteomyelitis appears in the Nigerian Journal of Clinical Practice, July 20.

The authors note that chronic osteomyelitis often affects children. Chronic bone infections with bone necrosis are more common in developing nations, they state, as "a result of poorly treated or untreated acute osteomyelitis."

Persistent infection in chronic osteomyelitis can lead to bone destruction and the formation of a sequestrum, a piece of dead bone that separates from the living bone. A sequestrum, the authors state, "serves as a sanctuary site that is isolated from the blood supply components of the immune system" and from the antibiotics used to treat the bacterial infection.

If an infection is untreated, the authors state, it tends "to cause extensive bone necrosis, forming long sequestra." 

Traditional treatment is to surgically remove the sequestrum to prevent further infection. The challenge for orthopedic surgeons is how to treat the gap in bone that can result when a large sequestrum is surgically removed.

Currently used techniques are distraction osteogenesis, a method of making a longer bone out of a short one, and bone graft. The particular treatment used depends on the individual needs of each patient. 

The authors sought to devise a technique that "is relatively easy to perform [and] does not require special expertise or equipment," making it a good option especially for developing countries.

Nonvascularized fibular grafts

In its case study, the surgical team performed a non-vascularized fibular graft on a 7-year-old patient. They used tissue transplanted from her fibula to fill the tibia bone gap that existed after a previous surgery had removed a sequestrum. 

"Previously," they wrote, it was thought that bone defects more than 6 centimeters were not amenable to non-vasularized fibular grafting, however, more recent studies have proven otherwise. Defects of up to 12-23 centimeters have been successfully reconstructive." But longer defects, they note, have higher complication rates.

Before the graft procedure, the patient was using crutches to walk. She couldn't put weight on her right leg after an operation a year earlier at another hospital.  After the new operation, the patient had a full-leg back plaster slab and later a cast. 

After 17 weeks the graft had taken and the gap in the fibula had re-ossified. The patient began partial weight bearing two days after the operation and full weight-bearing after six months.

The authors recommend managing chronic osteomyelitis in stages, first debriding the infection and removing the sequestrum, and, second, treating the bone gap once the infection is under control. 

They conclude by emphasizing the usefulness of this technique especially for hospitals that lack the skill and infrastructure required for using vascularized bone graft. "The sub-periosteal fibular harvest and use as a strut graft is a viable option with good outcomes."