Delayed Adjacent Level Spondylodiscitis after Initial Surgery with Instrumented Spinal Fusion: A Report of Three Cases and Review of the Literature.

To date, 2 cases of adjacent level spondylodiscitis occurring a few months after initial spinal fusion were reported. However, the development of delayed adjacent level spondylodiscitis is very rare. The authors report 3 cases of spondylodiscitis that occurred at the proximal adjacent level of the fused spine more than 1 year after the initial surgery. Antibiotic treatment was initially chosen in all three cases. In two of the cases, progressive neurological deficit occurred at the level of the infection due to compression of neural elements and spinal instability. For these patients, additional spinal fusion was performed. In each of the three cases, the selected treatment resulted in successful bony fusion at the level of the spondylodiscitis. According to the National Nosocomial Infections Surveillance System, deep wound infection is defined as occurring within 1 year after surgery with instrumentation. The spondylodiscitis in the present cases occurred more than 1 year after the initial surgery, suggesting that these cases may be considered as adjacent segment disease rather than surgical site infection.