Adult spinal deformity (ASD) is a major public health problem. There are pros and cons of the available treatment alternatives (surgical or non-surgical) and it had been difficult to identify the best treatment modality. To construct a statistical DA model to identify the optimum overall treatment in ASD. From an international multicentre database of ASD patients (968 pts), 535 who had completed 1year follow-up (371 non-surgical-NS, 164 surgical-S), constitute the population of this study. DA was structured in two main steps of: (1) baseline analysis (assessing the probabilities of outcomes, assessing the values of preference-utilities-, combining information on probability and utility and assigning the quality adjusted life expectancy (QALE) for each treatment) and (2) sensitivity analysis. Four hundred and thirty-two patients (309 NS, 123 S) had baseline and 1year follow-up ODI measurements. Overall, 104 (24.1%) were found to be improved (a decrease in ODI>8 points), 225 (52.1%) unchanged (-8>ODI>8) and 65 deteriorated. Surgery presented with a higher chance of improvement (54.2%) versus NS (9.7%). The overall QALE ranged from 56 to 69 (of 100years) and demonstrated better final QALE in the NS group (60 vs. 65, P=0.0038), this group having started with higher QALE as well (56 vs. 65years, P<0.0001). There were improvements in overall QALE in both groups but this was significant only in the surgical group (S from 56 to 60years, P<0.0001; NS from 65 to 65years, P=0.27). In addition, in the subgroup of patients with significant baseline disability (ODI>25) surgery appeared to yield marginally better final QALE (58 vs. 56years, P=0.1) despite very a similar baseline (54 vs. 54years, P=0.93). This study demonstrated that a single best treatment modality for ASD may not exist. Conservative treatment appears to yield higher (up to 6%) QALE compared to surgery, most probably secondary to a higher baseline QALE. On the other hand, surgery provides a significantly higher increase in QALE. Especially in patients with significant disability at baseline, the final QALE tended higher in the S group (although not significant). Finally, chances of a relevant improvement at first year turned out to be significantly lower with NS treatment.
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