Total Joint-Like Surgical Pathology May Help Diagnose Spinal Infections

An enhanced culture technique applied to tissue samples taken during revisions of instrumented posterior spine surgery may play a role in assisting surgeons in the diagnosis of spinal infections, based on results of a pilot study.

“Our real finding was that inflammation was uncommon adjacent to posterior spinal implants,” Jia-Wei Kevin Ko, M.D., said of the study, which involved prospectively collected, but retrospectively reviewed data.

Due to the poor sensitivity and specificity of bacterial cultures in this setting, Ko and colleagues evaluated the usefulness of the normal pathology cut-off of less than five cells per high-powered field (HPF) in analyzing tissue biopsies. They identified 80 posterior revision spine cases performed over 14 consecutive months and then analyzed five samples of biopsied tissue with the new method from 44 of the cases, for which full data were available, Ko said.

All the samples were taken from adjacent to the hardware, cultured for 10 days and sent for pathology analysis.

“This resulted in five cases which were infected and 39 which were not,” he said.

“Eighty percent of these demonstrated a positive pathology, which we defined as greater than five cells per HPF, and 39 were not infected, of which only 5 percent demonstrated as positive pathology. So, for our study, the definition of infection was clinical treatment of infection through the administration of antibiotics beyond the perioperative dosing,” according to Ko.

He mentioned limitations of the study included no gold standard with which to define infection and that the investigators’ clinical impression was a key component in the determination of which cases were infected and which were not infected.

“Based on these findings it is our conclusion that surgical pathology may be a useful adjunct to determine the presence or absence of infection in revision posterior spine cases,” Ko said.