Risk factors for major peri-operative complications in adult spinal deformity surgery: A multi-center review of 953 consecutive patients

Purpose: Major peri-operative complications for adult spinal deformity (ASD) surgery remain common. However, risk factors have not been clearly defined. Our objective was to identify patient and surgical parameters that correlate with the development of major peri-operative complications with ASD surgery. Methods: This is a multi-center, retrospective, consecutive, case-control series of surgically treated ASD patients. All patients undergoing surgical treatment for ASD at eight centers were retrospectively reviewed. Each center identified 10 patients with major peri-operative complications. Randomization tables were used to select a comparably sized control group of patients operated during the same time period that they did not suffer major complications. The two groups were analyzed for differences in clinical and surgical factors. Analysis was restricted to non-instrumentation related complications. Results: At least one major complication occurred in 80 of 953 patients (8.4 %), including 72 patients with non-instrumentation related complications. There were no significant differences between the complications and control groups based on the demographics, ASA grade, co-morbidities, body mass index, prior surgeries, pre-operative anemia, smoking, operative time or ICU stay (p > 0.05). Hospital stay was significantly longer for the complications group (14.4 vs. 7.9 days, p = 0.001). The complications group had higher percentages of staged procedures (46 vs. 37 %, p = 0.011) and combined anterior-posterior approaches (56 vs. 32 %, p = 0.011) compared with the control group. Conclusion: The major peri-operative complication rate was 8.4 % for 953 surgically treated ASD patients. Significantly higher rates of complications were associated with staged and combined anterior-posterior surgeries. None of the patient factors assessed were significantly associated with the occurrence of major peri-operative complications. Improved understanding of risk profiles and procedure-related parameters may be useful for patient counseling and efforts to reduce complication rates.