Unexpected Bacteriological Finding Using Sonication in Revision Spine Surgery (Report of Two Cases)

The number of spine surgeries around the world is increasing in recent years. Each time, new techniques and minimal invasive procedures are developing. However, the incidence of postoperative spinal infections (PSII) ranges from 0.7% to 20%. In cases of infection, identification of the pathogen is essential to apply the appropriate antimicrobial treatment. Most of the usual techniques are based on the recovery of samples from the periprosthetic tissue followed by inoculation in culture media. In the last years, the presence of biofilm-forming bacteria has increased, which has the ability to decrease the sensitivity of the traditional culture method. The application of sonication prior to culture on the rescued inert material, disrupts the biofilm and generates a significantly higher recovery of bacterial growth compared to conventional tissue culture. We present a case series from our service of patients undergoing apparently aseptic lumbar spine revision surgery with positive culture by sonication.