Development and current use of local antibiotic carriers in spondylodiscitis

The current study situation regarding the duration of systemic antibiotic treatment for spondylodiscitis is inhomogeneous and varies between 4–12 weeks. Due to the many undesirable side effects the aim is to achieve complete healing without recurrence or hematogenous scatter within the shortest possible period of time. The present pilot study investigated whether the additional application of a local antibiotic carrier to the surgically treated intervertebral disc space can contribute to a further reduction of treatment duration.

In the pilot study 20 patients with acute spondylodiscitis and indications for surgical intervention were included. Surgical treatment was carried out by dorsal instrumentation, radical debridement of the site of infection, and cage interposition in the affected disc space. The remaining disc space was filled with homologous cancellous bone and antibiotic-loaded calcium sulfate hydroxyapatite pellets. A classification into a long-term and a short-term antibiotic group was performed. Both groups initially received a 10-day parenteral antibiotic administration. This was followed by oral antibiotics for 2 or 12 weeks, depending on the group. During the 12-month follow-up inflammation parameters, the local infection situation as well as the bony fusion and antibiotic tolerance were regularly checked.

The average age of the patients was 66.7 ± 11.2 years. Intraoperative detection of pathogens was successful in 65%. In 60% the antibiotic carrier was loaded with gentamicin, in 40% with vancomycin. At follow-up, all patients except one in the short-term antibiotic group had inflammation parameters within the normal range after 3 months. In the long-term antibiosis group, two patients still showed elevated infection values after 3 months, otherwise the values were within the normal range. After 12 months a complete cure of the infection was achieved in all patients. Antibiotic treatment intolerance occurred in 10% of the short-term antibiotic group and in 50% of the long-term group.

The results of the present pilot study show that with the additional use of absorbable local antibiotic carriers in the surgical treatment of bacterial spondylodiscitis it is possible to shorten the duration of systemic antibiotic treatment to 3 weeks. This can reduce the side effects and incompatibility of treatment and still achieve similar healing results.