Which Complication Is More Predictive of Death After Metastatic Spine Surgery: Medical or Surgical Complications?

Introduction: Among metastatic spine patients requiring surgery, it is unknown which complication – medical or surgical – impact patients’ course more. In patients undergoing metastatic spine surgery, we sought to compare the impact of medical vs. surgical complications on: 1) 1-year mortality, 2) overall survival, and 3) time-to-death.

Methods: A single-center, retrospective, cohort study was undertaken of patients who underwent metastatic spine surgery for extradural disease between 2010-21. Inclusion criteria were: surgically treated intermediate or radioresistant tumors with spinal cord compression and a postoperative complication. The primary exposure variable was binarized as a medical (not directly related to the surgical procedure) or surgical (directly related to the surgery) complication. Patients with both medical and surgical complications (N=20) were excluded. The primary outcome variables were: 1) 1-year mortality, 2) overall survival, and 3) time-to-death. Descriptive and univariate/multivariable Cox regression were performed.

Results: Of 101 patients with either medical or surgical complications after metastatic spine surgery, median overall survival was 123 days (IQR=41-556) and median time to local recurrence was 112 days (IQR=32-362.5). Medical and surgical complications were seen in 46 (45.5%) and 55 (54.4%) patients, respectively. Those with medical complications had lower preoperative KPS (60.9 vs 67.3,p=0.044). Postoperatively, patients with medical complications had longer hospital stays (10.8 vs 6.0 days, p=0.001) and less often discharged home (43.5% vs 63.6%,p=0.021). Medical complications were associated with a higher 1-year mortality (71.7% vs. 40.0%,p=0.001) and a shorter time to death (228.8vs. 632.1days,p=0.003). Kaplan-Meier plots showed decreased survival in patients with medical vs. surgical complications (median 51.5 vs. 348 days, log-rank p< 0.001). On multivariable Cox/logistic regression, medical complications were an independent risk factor for higher overall mortality (HR=2.26 95%CI= 1.40-3.66,p < 0.001) and death within one year (OR=2.78, 95%CI= 1.56-4.95,p < 0.001).

Conclusion : While spine surgeons are adept at recognizing and treating surgical complications, medical complications significantly impact survival and time-to-death more than surgical complications in patients undergoing metastatic spine surgery. Medical optimization before and immediately after surgery is critically important in patients undergoing metastatic spine surgery.