LONG TERM OUTCOME AND QUALITY OF LIFE FOLLOWING PYOGENIC SPINAL INFECTION

Abstract

There is little published data concerning long-term outcome in pyogenic spinal infection. Previous studies have used either neurological outcome in isolation, or non-validated quality of life measure instruments yielding data that is difficult to interpret.

To assess long-term outcome following pyogenic spinal infection through standardised outcome measures, Oswestry Disability Index (ODI) and Short Form-36 (SF-36) were utilised.

All cases of pyogenic spinal infection presenting to a single institution over the period 1993–2003 were retrospectively identified. Inclusion in each case was based on consistent clinical, imaging and microbiology criteria. The follow-up was by clinical review, American Spinal Injury Association (ASIA) classification, ODI and SF-36. The outcome was compared to normative data for the Irish population.

Twenty-nine cases of pyogenic spinal infection were identified. Nineteen patients (66%) had an adverse outcome at a median follow-up of 61 months, despite only 5 patients (17%) who had persistent neurological deficit according to ASIA classification. A significant difference in SF-36 PF (physical function) scores was observed between patients with adverse outcome and those who recovered (p=0.003). SF-36 scores failed to reach those of a normative population, even after apparent full recovery. A strong correlation was observed between ODI and SF-36 Physical Function scores (rho=0.61, p< 0.05). Seventeen percent (n= 5) of admissions resulted in acute sepsis-related death. Delay in diagnosis of spinal infection (p= 0.025) and neurological impairment at diagnosis (p< 0.001) were associated with neurological deficit at follow-up examination. Previous spinal surgery was a significant predictor of adverse outcome in patients requiring readmission < 1 year (p= 0.018).

The finding of high rates of adverse outcome and using SF-36 and ODI suggests under-reporting of poor outcome in other series. We advocate use of validated standardised spinal outcome questionnaires to accurately assess long-term outcome and facilitate comparison between case series.