The Impact of Frailty on Mechanical Complications Following Lumbar Fusion Surgery: A Propensity Score-matched Analysis.

OBJECTIVE

To evaluate the impact of frailty on mechanical complications following lumbar fusion surgery in elderly patients.

METHODS

We retrospectively enrolled elderly patients who underwent lumbar fusion surgery between August 2021 and March 2023 and used propensity score matching (PSM) to control for confounding factors. Frailty was assessed using the 5-item modified Frailty Index (mFI-5). Univariate and multivariate logistic regression analyses were performed to compare the incidence of postoperative mechanical complications and revision rates between frail and non-frail patients.

RESULTS

After PSM, a total of 113 well-matched patient pairs were obtained. Frail patients had significantly longer length of stay (LOS) and higher paraspinal muscle fat infiltration ratios (FI%) compared to non-frail patients (P < 0.05). With regard to radiographic spinopelvic alignment and postoperative functional outcomes, frail patients exhibited significantly higher preoperative pelvic tilt (PT), as well as higher Oswestry Disability Index (ODI) and Visual Analog Scale for back (VAS-back) scores at the 2-year follow-up. Multivariable regression analysis further demonstrated that frail patients were 7.4 times more likely to develop adjacent segment degeneration (ASD), 6.8 times more likely to undergo any revision surgery, and 8.3 times more likely to require revision specifically for ASD compared to non-frail patients.

CONCLUSIONS

In this study, patients with frailty had significant higher rate of paravertebral muscle FI%, as well as a relatively high incidence of ASD and reoperation, highlighting its value in preoperative risk stratification.