- Background: The Spinal Instability Spondylodiscitis Score (SISS) was created as a tool in the evaluation of stability in spinal pyogenic infections. Despite spine surgeon growing interest, the correlation between SISS scores and clinical outcomes remains inadequately explored. Moreover, the prognostic significance of initial SISS scores in predicting subsequent radiological progression is of paramount importance for effective treatment planning and prognostication.
Methods: This study involved a retrospective collection of clinical data and evaluation of radiological images from two centers located in the United Kingdom and Germany. The primary outcomes were defined as unfavorable outcomes (modified Rankin Scale, mRS 4-6) and the development of a neurological deficit during treatment. Radiological progression in patients treated conservatively and monitored with MRI was assessed and categorized into minor progression (including endplate erosion or disc collapse) and major progressionBackground: The Spinal Instability Spondylodiscitis Score (SISS) was created as a tool in the evaluation of stability in spinal pyogenic infections. Despite spine surgeon growing interest, the correlation between SISS scores and clinical outcomes remains inadequately explored. Moreover, the prognostic significance of initial SISS scores in predicting subsequent radiological progression is of paramount importance for effective treatment planning and prognostication.
Methods: This study involved a retrospective collection of clinical data and evaluation of radiological images from two centers located in the United Kingdom and Germany. The primary outcomes were defined as unfavorable outcomes (modified Rankin Scale, mRS 4-6) and the development of a neurological deficit during treatment. Radiological progression in patients treated conservatively and monitored with MRI was assessed and categorized into minor progression (including endplate erosion or disc collapse) and major progression (encompassing bony destruction, kyphotic or scoliotic angulation, or translation).
Results: The study incorporated 205 cases, 91 of which underwent conservative treatment, while 114 received surgical intervention. The cohort had a mean age of 67 years, with 123 male participants. Patients were categorized based on their SISS scores as stable (23 cases), potentially unstable (147 cases), and unstable (35 cases). Within the stable group, 6 patients (26%) developed neurological deficits. Unfavorable outcomes were observed in 9 out of 23 cases (39%) in the stable group, 54 out of 147 cases (37%) in the potentially unstable group, and 18 out of 35 cases (52%) in the unstable group.
ANOVA variance analysis revealed statistically significant differences in continuous SISS scores between patients with no impairment (p<0.01) and those with unfavorable outcomes (p<0.05), as compared to other mRS categories. Subfactors ‘Spinal alignment’ and ‘Bone lesion’ had the strongest impact on the continuous SISS (p<0.001).
The multilevel regression analysis indicated that the strongest predictor of an unfavorable mRS outcome were having a neurological deficit at admission (p<0.001), and SIRS at admission (p=0.04). The SISS score and location factors did not reach conventional levels of statistical significance in this model.
Major radiological progression involving the development of deformity was present in 47% across all conservatively treated groups.
Conclusions: The findings suggest that, while subfactors like 'Spinal alignment' and 'Bone lesion' are mainly determining SISS, the overall score's impact on mRS outcomes is less clear. Other factors, not included in the SISS, might also be important in determining outcomes. Furthermore, the data also indicates that an assessment of stability via the SISS is reflective of a specific point in time and that neurological impairments can emerge in conjunction with radiological progression. Hence, ongoing clinical and radiological reassessment during treatment is imperative to preemptively identify the risk of neurological deterioration.…
