Objectives: To analyse the clinical, microbiological and radiological characteristics, and to identify risk factors of vertebral compressive fracture (VF) in spontaneous pyogenic vertebral osteomyelitis (VO).
Methods: A retrospective clinical study and blinded radiological review of adult patients with VO.
Results: Eighty-eight patients were included: 57 (65%) had a definitive diagnosis of VO (positive microbiology), and 31 (35%) had a probable diagnosis of VO. Of these, 27 (30.7%) presented with VF at diagnosis of VO, and 4 afterwards (total 31, 35.2%). Patients with VF were considered to be at higher risk of osteopenia--they were older (74 vs 66 years, p = 0.013), and included high percentage of women (33 vs 41%, NS)--; and presented more dorsal involvement (56 vs 21%; p < 0.007). Causal microorganisms were similar between groups (VF, no VF). The time to diagnosis of VO was longer in the presence of VF (65 vs 23 days, p = 0.001), and also in cases with no isolated organisms. All patients received antibiotics, and just one patient required spinal stabilisation (VF). After 357 median days of follow-up, all patients were cured. Clinical improvement (residual pain, functional recovery) tended to be slower in patients with VF (log-rank 0.19 and 0.15, respectively), but clinical symptoms were similar in most patients at the last follow-up (VF, no VF).
Conclusions: VF is a common complication in pyogenic VO that causes slower clinical recovery. Risk factors of VF are: osteopenia, a delayed diagnosis and dorsal involvement. Conservative management is probably appropriate for most cases, but spinal stabilisation should be considered in some specific cases.
Keywords: Pyogenic vertebral osteomyelitis; Spodylodiscitis; Vertebral collapse; Vertebral compressive fracture.