According to a study published in The Spine Journal, the Spine Adverse Events Severity (SAVES) system—a recording instrument created to comprehensively record the mobility and mortality associated with complex spinal surgery—can be generalised to non-Canadian populations of all ages. The study—which was recognised as a “Best Paper” at the 30th Annual Meeting of the North American Spine Society (NASS; 14–17 October, Chicago, USA)—was led by Sven Karstensen and Benny Dahl, University of Copenhagen, Denmark.
The primary aim of this study was to discover whether the SAVES system could be generalised to a non-Canadian population of patients. Secondly, the study aimed to confirm whether a prospective identification of adverse events was more effective than historic retrospective reporting. Thirdly, age and emergency procedures were evaluated as potential risk factors for acute care adverse events.
The study prospectively recorded adverse events associated with spinal surgery, until discharge, using the SAVES questionnaire for all adult and paediatric patients undergoing surgery at a tertiary referral centre between 1 January and 31 December 2013. Retrospective data from 1 November 2011 to 31 October 2013 as well as prospective data were then compared with the results reported by Street et al in a similar study conducted in Canada in 2008. Retrospective data was extracted from hospital charts according to the same SAVES form as used with the prospective cohort.
The SAVES system recognises a number of adverse events, allowing for the input of a non-predefined adverse event as “other”. Adverse events were ranked dichotomously according to their effect on patient outcome and length of stay, with a grade of one indicating that the adverse events had an impact on these variables, while a grade zero indicated that an adverse event had “no impact”. Any questions the researchers had were reviewed and answered by surgical staff on a weekly basis, and the forms were concluded upon the patient’s discharge.
All relevant SAVES forms were completed for the 679 procedures included in the one-year study. The mean number of perioperative adverse events was 2.1 per patient. This highlights the similarities with the Street et al study, which recorded a mean of two perioperative adverse events per patient. Comparable results were found between mean length of stay and other patient outcome data. When the mean length of stay was compared for paediatric and adult patients, as well as for those older and younger than 65 years of age, no significant differences were found.
These results confirm that the SAVES system can be generalised to a European setting. The authors suggest that this may be limited, most notably, by the inclusion of paediatric patients in this study. The study was also limited by its use of length of stay as an indicator of health economy, which the authors note can be an inconsistent variable. However, they assert that there may be a relation between length of stay and even minor adverse events. The mean length of stay in the present study was significantly different to that recorded in the Canadian paper, but the authors note that this could be due to different discharge criteria.
Confirming the link between the occurrence of adverse events and long-term outcomes, according to the authors, could improve health economic aspects of spine surgery. “The primary purpose in future studies will be to relate the occurrence of adverse events to long-term outcomes. This could potentially improve the health economic aspects of spine surgery, justifying the increased resources used for the SAVES methodology,” write the authors.
The researchers assert the necessity of a system such as SAVES for the proper recording of morbidity and mortality associated with complex spinal surgery, “A prospective, formalised study design is necessary to correctly identify complications and adverse events in spine surgery.”