# Impact of a History of COVID-19 Infection on Postoperative Complications in Spinal Surgery: A Nationwide Cohort Study

## TL;DR

This study found that spinal surgery performed shortly after a history of COVID-19 increases the risk of certain postoperative complications like pneumonia and infections.

## Contribution

The study is the first to show how the timing of spinal surgery after a prior COVID-19 infection affects specific postoperative complication risks.

## Key findings

- Surgery within one month of a prior COVID-19 diagnosis increases the risk of postoperative pneumonia.
- Surgery 1–3 months after infection raises the risk of spinal and implant-related infections.
- The risk of infections remains elevated even when surgery occurs 3–6 months after a prior infection.

## Abstract

Background/Objectives: The postoperative implications of a history of coronavirus disease 2019 (COVID-19) in patients undergoing spinal surgery remain inadequately defined. This study investigated whether a history of COVID-19 is associated with increased postoperative complication risk and assessed how surgical timing after infection influences outcomes. Methods: Patients who underwent spinal surgery in 2020 were identified. Individuals with a confirmed history of COVID-19 were matched 1:3 by age and sex to uninfected controls. Patients were categorized by the interval between COVID-19 diagnosis and the index surgical date (≤1 month, >1–≤3 months, or >3–≤6 months). Postoperative pulmonary, cardiovascular, thromboembolic, infectious, and mortality outcomes were evaluated. Cumulative risks were estimated using Kaplan–Meier analysis, and adjusted hazard ratios (HRs) were determined using multivariable Cox proportional hazards models controlling for demographic and clinical factors. Results: Surgery performed ≤1 month after COVID-19 diagnosis was associated with significantly higher risks of pneumonia within 3 months (HR 3.91; p = 0.031) and 6 months postoperatively (HR 3.12; p = 0.049). Patients undergoing surgery >1–≤3 months after COVID-19 demonstrated increased risk of spinal and implant-related infections within 3 months (HR 2.12; p = 0.040), and this elevated risk persisted when surgery occurred >3–≤6 months after infection (HR 2.00; p = 0.022). No significant differences were observed in cardiovascular, thromboembolic, or mortality outcomes. Conclusions: A history of COVID-19 infection was associated with postoperative pneumonia and spinal and implant-related infections following spinal surgery. These findings suggest that prior COVID-19 infection may be a relevant consideration in perioperative risk assessment and surgical planning.