Trends in Functional Outcomes After Aneurysmal Subarachnoid Hemorrhage During a Rapid Shift From Surgical to Endovascular Treatment

Although spinal infections are still associated with high morbidity and mortality, there is a lack of established classification systems with corresponding therapeutic recommendations.In 2022, the Spinal Instability Spondylodiscitis Score (SISS) was published to assess spinal stability in spondylodiscitis and demonstrated high reliability and validity in internal evaluations.However, a high proportion of potentially unstable lesions posed a limitation in clinical application.Therefore, the aim of the present study was to adapt the SISS by the AO Knowledge Forum Trauma and Infection and validate it internationally.Methods: The SISS was initially modified through international expert consensus (Table 1).Reliability analyses were then conducted both within the expert group of the AO Knowledge Forum Trauma and Infection and within a group of international spine surgeons.In the expert group, ten cases were assessed by 15 experts in two separate sessions.For international validation, 15 cases were evaluated by 111 members of AOSpine, also in two sessions at different time points.Statistical analysis included calculation of Fleiss' kappa for individual parameters (bony lesion, spinal alignment, location) and the intraclass correlation coefficient (ICC) for the total score.Results: In the expert group, excellent intrarater reliability of 0.90 (0.84-0.96) was observed.In the international validation, intrarater reliability was 0.82 (0.71-0.92).Interrater reliability in the expert group was 0.87 (0.77-0.97) in the first and 0.89 (0.80-0.98) in the second evaluation.In the international validation, interrater reliability was 0.75 (0.62-0.89) and 0.73 (0.59-0.87), respectively.Compared to the gold standard, agreement in all parameters exceeded 85% in the expert group and 78% in the international validation.Conclusions: The mSISS is a comprehensive and easy-to-use classification system with excellent reliability for assessing spinal stability in the presence of spondylodiscitis.It is important to note that the mSISS solely evaluates spinal stability and does not consider other surgical indications such as neurological impairment or epidural abscess.