# Sarcopenia as a predictor of cage subsidence following stand-alone oblique lumbar interbody fusion in non-osteoporotic patients

## TL;DR

This study finds that muscle loss (sarcopenia) increases the risk of cage subsidence after a specific spinal surgery in non-osteoporotic patients.

## Contribution

Identifies sarcopenia as a novel predictor of cage subsidence in non-osteoporotic patients undergoing oblique lumbar interbody fusion.

## Key findings

- Cage subsidence occurred in 32.7% of non-osteoporotic patients after SA-OLIF.
- Sarcopenia, age over 59.5 years, and low bone mineral density predict cage subsidence.
- Patients with sarcopenia had nearly four times higher odds of cage subsidence.

## Abstract

This study aimed to identify predictors of cage subsidence following stand-alone oblique interbody fusion (SA-OLIF) in non-osteoporotic patients.

A retrospective analysis was performed on 98 patients who underwent SA-OLIF. Cage subsidence was defined to have occured when a cage was subsided into the adjacent endplate by more than 2 mm on the last follow up radiographs. Patients were categorized into subsidence and non-subsidence groups accordingly. Patient characteristics, radiographic parameters, and clinical outcomes were recorded. Sarcopenia was assessed using the L3 skeletal muscle index on axial computed tomography images. Multivariate logistic regression analysis was conducted to identify the predictors of cage subsidence following SA-OLIF.

Of the 98 patients who underwent SA-OLIF, subsidence occurred in 32 (32.7%). The subsidence group had a higher mean age (P = 0.005) and lower bone mineral density (BMD) (P < 0.001). The prevalence of sarcopenia was significantly greater in the subsidence group compared with the non-subsidence group (P = 0.003). Multivariate logistic regression identified sarcopenia (P = 0.021), age (P = 0.011), and BMD (P < 0.001) as predictors of cage subsidence. The areas under the curve for age and BMD in predicting cage subsidence were 0.676 and 0.783, respectively.

Cage subsidence following SA-OLIF was a common complication in non-osteoporotic patients, with an incidence rate of 32.7%. Preoperative sarcopenia, age of >59.5 years, and T-score < −1.9 were predictors of cage subsidence following SA-OLIF in non-osteoporotic patients. Patients with sarcopenia had nearly 4-fold increased odds of subsidence. OLIF with instruments might be considered an alternative surgical method for patients with these predictor factors to decrease the incidence of cage subsidence.