# Expandable Cage Versus Mesh Cage for the Treatment of Vertebral Osteomyelitis

## TL;DR

This study compares expandable and mesh cages for treating vertebral osteomyelitis and finds that expandable cages lead to higher costs and more complications.

## Contribution

The first direct comparison of expandable and mesh cages in vertebral osteomyelitis treatment outcomes.

## Key findings

- Expandable cages had higher nonunion and revision rates compared to mesh cages.
- Expandable cages were associated with significantly higher in-hospital costs.
- Expandable cage use was identified as an independent risk factor for treatment failure.

## Abstract

Background and objective

Consensus regarding the optimal method for anterior column reconstruction in vertebral osteomyelitis has not been established. Direct comparisons between mesh and expandable cages have not been reported. This study aimed to evaluate differences in clinical outcomes, including revision rates, recurrence rates, complications, and costs, between these two reconstruction methods, as well as to identify independent risk factors for treatment failure in patients undergoing anterior column reconstruction with metal implants.

Methods

Clinical records of consecutive patients who underwent surgical intervention for vertebral osteomyelitis at a single institution between 2012 and April 2024 were reviewed. Patients who underwent anterior column debridement with either a mesh or an expandable cage, along with posterior fusion involving four or more levels, were included. Clinical outcomes, including nonunion, revisions, recurrence, and costs, were compared between the mesh and expandable cage groups.

Results

Ninety-two patients were included: 20 (22%) in the expandable cage group and 72 (78%) in the mesh cage group. The expandable cage group had a significantly higher nonunion rate (35% vs. 9.7%, p = 0.014) and revision rate (30% vs. 9.7%, p = 0.032). Costs were also higher in the expandable cage group, with a significant difference in in-hospital costs (Expandable: $77,737 ± 34,586; Mesh: $63,250 ± 27,899; p = 0.028). Multivariable analysis identified the number of fused levels (OR = 1.32, 95% CI: 1.05-1.71; p = 0.024) and the use of an expandable cage (OR = 3.27, 95% CI: 1.04-11.02; p = 0.046) as independent risk factors for treatment failure, defined as revision surgery, recurrence, or mortality.

Conclusions

This study is the first to compare outcomes between expandable cages and mesh cages in patients with vertebral osteomyelitis. The findings suggest that the use of an expandable cage for reconstruction after anterior column debridement is associated with higher costs and increased risks of nonunion and revision surgery compared with mesh cages. Additionally, the use of an expandable cage was identified as an independent risk factor for treatment failure in vertebral osteomyelitis.