Risk factors and prognosis of vertebral compressive fracture in pyogenic vertebral osteomyelitis

To analyse the clinical, microbiological and radiological characteristics, and to identify risk factors of vertebral compressive fracture (VF) in spontaneous pyogenic vertebral osteomyelitis (VO).

A retrospective clinical study and blinded radiological review of adult patients with VO.

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).

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.