Unplanned Readmission Is Associated With Decreased Overall Survival and Performance After Metastatic Spine Surgery

Abstract

Study Design.Retrospective case-control study.Objective.In a cohort of patients undergoing metastatic spine surgery, we sought to: (1) identify risk factors associated with unplanned readmission, and (2) determine the impact of an unplanned readmission on long-term outcomes.Summary of Background Data.Factors affecting readmission after metastatic spine surgery remain relatively unexplored.Materials and Methods.A single-center, retrospective, case-control study was undertaken of patients undergoing spine surgery for extradural metastatic disease between 02/2010 and 01/2021. The primary outcome was 3-month unplanned readmission. Preoperative, perioperative, and tumor-specific variables were collected. Multivariable Cox regression was performed, controlling for tumor size, other organ metastasis, and preoperative/postoperative radiotherapy/chemotherapy.Results.A total of 357 patients underwent surgery for spinal metastases with a mean follow-up of 538.7±648.6 days. Unplanned readmission within 3 months of surgery occurred in 64/357 (21.9%) patients, 37 (57.8%) were medical, 27 (42.2%) surgical, and 21 (77.7%) were related to their spine surgery. No significant differences were found regarding demographics and preoperative variables, except for insurance, where most readmitted patients had private insurance compared with nonreadmitted patients (P=0.021). No significant difference was found in preoperative radiotherapy/chemotherapy. Regarding perioperative exposure variables, readmitted patients had a higher rate of postoperative complications (68.8%vs.24.2%,P<0.001) and worse postoperative Karnofsky Performance Score (P=0.021) and Modified McCormick Scale (P=0.015) at the time of first follow-up. On multivariate logistic regression, postoperative complications were associated with increased readmissions (odds ratio=1.38, 95% CI=1.25–1.52,P<0.001). Regarding the impact of unplanned readmission on long-term tumor control, unplanned readmission was associated with shorter time to local recurrence (log-rank;P=0.029) and reduced overall survival (OS) (log-rank;P<0.001). On multivariate Cox regression, other organ metastasis [hazard ratio (HR)=1.48, 95% CI=1.13–1.93,P=0.004] and 3-month readmission (HR=1.75, 95% CI=1.28–2.39,P<0.001) were associated with worsened OS, with no impact on LR. Postoperative chemotherapy was significantly associated with longer OS (HR=0.59, 95% CI=0.45–0.77,P<0.001).Conclusions.Postoperative complications were associated with unplanned readmission following metastatic spine surgery. Furthermore, 3-month unplanned readmission was associated with a shorter time to local recurrence and decreased OS. These results help surgeons understand the drivers of readmissions and the impact of readmissions on patient outcomes.Level of Evidence.3.