Objectives: Spontaneous spinal infection (SI) is a quite rare but serious entity. This
study aimed to evaluate outcome and follow-up data of SI cases without a microbiological
diagnosis (suspected SI).
Methods: We undertook a retrospective, comparative study of 82 spontaneous SI cases in
adults presenting over an 11-year period to two Italian hospitals.
Results: The diagnostic yields of blood culture, percutaneous needle biopsy of spine, and surgical
sample culture were 43.6%, 72.7%, and 91.6%, respectively. Overall, causative organisms
were identified in 60 (73.2%) cases, the most frequently isolated pathogens being Staphylococcus
aureus and Mycobacterium tuberculosis. The median diagnostic delay was similar
(pZ0.39) in pyogenic (1 month) and suspected (0.5 month) SI cases, and longer in tuberculous
cases (4 months) than in the other SI case groups (pZ0.069 and pZ0.062, respectively). All
patients received antibiotic treatment, and 21 (25.5%) underwent surgery, that was required
more frequently in tuberculous (40.7%) than in pyogenic (25.0%) and suspected SI cases
(9.1%) (pZ0.028). Of 67 patients who completed a 1-year follow-up period, 24 had persisting
painful disability that was more frequent in tuberculous (66.7%) cases than in pyogenic (21.7%)
and suspected SI (15.0%) cases (pZ0.03).
Conclusions: Although a microbiological diagnosis was not achieved in nearly a quarter of SI
cases, both diagnostic delay and outcome were similar to those of pyogenic SI cases. Earlier
recognition of tuberculous SI is mandatory, as this is associated with the highest long-term
morbidity
