Therapeutic Outcomes of Pyogenic Vertebral Osteomyelitis Requiring Spinal Instrumentation

We read with great interest the recent article by Arnold et al.(1) on factors associated with treatment failure in pyogenic vertebral osteomyelitis requiring spinal instrumentation. They re-ported a treatment failure rate of 23.4 % (95 % confidence interval [95 % CI], 16.0 % to 32.9%), considerably higher than the rate of 1.7 % (95%CI, 1.0 % to 3.0%) presented in a literature review that included 30 previous publications describing 689 cases (2). As pointed out by the authors, the use of a strict case definition precluded noninfectious vertebral diseases requiring the place-ment of hardware, and it might have been responsible for the higher rate of treatment failure. It is also worth noting that a sub-stantial proportion of the microbiologically diagnosed cases were caused by drug-resistant organisms such as methicillin-resistant Staphylococcus aureus (MRSA) (40.5 % [32/79]) and Pseudomonas species (8.9 % [7/79]). The treatment failure rate was higher in the cases of MRSA (31.3 % [10/32]; P 0.11) and Pseudomona