Introduction: Because of the high incidence of major perioperative adverse events, spine surgery in dialysis patients should be recommended carefully after consideration of its risks and benefits. However, the benefits of spine surgery in dialysis patients remain unclear because of the lack of long-term outcomes. The purpose of this study is to elucidate the long-term outcomes of spine surgery in dialysis patients, focusing on activities of daily living (ADLs), life expectancy, and risk factors for postoperative mortality.
Methods: Consecutive 73 dialysis patients underwent surgeries for spinal disorders in our institution between 2005 and 2017. Because 40 of these were lost to follow-up, standardized telephone interviews for patients or patients’ families were performed to assess the long-term outcomes. Sixty-five patients were finally enrolled in this study, excluding eight patients whose interviews were not conducted (follow-up rate, 89.0%). The study group included 35 men and 30 women, with a mean age of 65.6 years (range 53-84 years). Because some patients died during the follow-up period, the follow-up period was defined as the time between date of surgery and death or the final follow-up, and the mean follow-up period was 75.3 months (range 1-157 months). With regard to surgical sites, 39 patients of the 65 patients had lumbar surgeries as index spine surgeries, 22 patients had cervical surgeries, and 4 patients had thoracic surgeries, respectively. Dialysis period, cause of renal failure, survival time, number of spine surgeries, and ADL function level were reviewed retrospectively. The postoperative survival rate was calculated using the Kaplan-Meier method, and risk factors for postoperative mortality were investigated using a generalized Wilcoxon test and multivariate Cox proportional-hazards model.
Results: Compared with preoperative ADLs, ADLs significantly improved at discharge after surgery and at the final follow-up. However, 16 of the 65 patients (24.6%) underwent multiple surgeries, and 34 (52.3%) died during the follow-up period. Kaplan-Meier analysis revealed that the survival rate after spine surgery was 95.4% at 1 year, 86.2% at 3 years, 69.6% at 5 years, 59.7% at 7 years, and 28.7% at 10 years, and the overall median survival time was 99 months. Multivariate Cox regression analysis showed that a dialysis period of ≥ 10 years was a significant risk factor, but not patient’s age, cause of renal failure, DSA, and preoperative ADLs.
Discussion: Spine surgery in dialysis patients improved and maintained ADLs in the long term. The survival rates of dialysis patients after spine surgery in this study was comparable to the survival rate of dialysis patients in Japan after dialysis induction (89.9% at 1 year, 76.4% at 3 years, 60.8% at 5 years, 49.1% at 7 years, and 35.9% at 10 years), which indicates that spinal surgery does not worsen life expectancy. However, dialysis patients undergoing spine surgery require multiple surgeries more frequently, and a dialysis period of ≥ 10 years is a significant risk factor for postoperative mortality.