# Risk factors for 90-day unplanned readmission after open posterior lumbar fusion in the elderly

## TL;DR

This study identifies risk factors for unplanned hospital readmission within 90 days after a common spinal surgery in elderly patients.

## Contribution

The study provides a comprehensive analysis of risk factors for early readmission after lumbar fusion in elderly patients.

## Key findings

- Eight percent of elderly patients were readmitted within 90 days after open posterior lumbar fusion.
- Higher age, heart disease, and surgical complications were significant risk factors for readmission.
- Identifying these risk factors can help improve preoperative planning and reduce readmissions.

## Abstract

The inescapable trend of an aging population has made lumbar fusion increasingly common in elderly individuals. This study aimed to explore the risk factors associated with unplanned readmission within 90 days after open posterior lumbar fusion (OPLF) in elderly patients (≥ 60 years old).

We retrospectively analyzed clinical data of patients who underwent OPLF at two spine centers between June 2010 and June 2024. Patients were divided into readmission and non-readmission groups according to whether they were unplanned readmitted within 90 days of the primary surgery. Demographic and clinical outcomes were compared between the two groups. Multivariate logistic regression was used to analyze risk factors for 90-day readmission.

Of the total, 8.6% (157/1826) of elderly patients experienced unplanned readmission within 90 days of the initial surgery. Factors including age, body mass index (BMI), American Society of Anesthesiologists (ASA) score (grade 3), history of diabetes, heart disease, respiratory disease, preoperative malnutrition, severe osteoporosis (T < −3.5), incidental durotomy, surgical segment, and surgical time in the readmission group were significantly higher than those in the non-readmission group. Multivariate logistic regression analysis suggested that higher age (p = 0.040, OR: 1.040, 95% CI: 1.002–1.079), ASA score ≥ grade 3 (p = 0.022, OR: 1.634, 95% CI: 1.074–2.485), heart disease (p = 0.021, OR: 1.971, 95% CI: 1.107–3.511), preoperative malnutrition (p = 0.028, OR: 1.701, 95% CI: 1.058–2.734), severe osteoporosis (p = 0.029, OR: 1.652, 95% CI: 1.054–2.588), surgical segment (p = 0.020, OR: 1.521, 95% CI: 1.067–2.169), and incidental durotomy (p = 0.012, OR: 2.193, 95% CI: 1.189–4.045) were risk factors for unplanned readmission.

We identified seven risk factors associated with unplanned readmission within 90 days after OPLF in elderly patients. This information may assist clinicians in preoperative evaluations of patients to develop better surgical strategies.