Abstract
<title>Abstract</title> <p>Background Probable sarcopenia, defined by low muscle strength, is a common and potentially modifiable preoperative condition in older adults undergoing lumbar spine surgery. We evaluated how probable preoperative sarcopenia, identified with simple bedside tests, affects postoperative recovery, and whether the available tests are interchangeable. Methods In this prospective single-centre observational cohort study at a tertiary university hospital, we screened 123 consecutive adults (≥ 45 years) scheduled for elective lumbar disc herniation surgery and analysed 111. Probable sarcopenia was assessed preoperatively using the SARC-F questionnaire, hand-grip strength (HGS), BMI-adjusted HGS (HGS/BMI), and the five-time sit-to-stand test (5-STS). The primary outcomes were length of hospital stay (LOS) and time to independent ambulation over 20 m without a walking aid. Multivariable logistic regression, adjusted for age, sex, BMI, ASA status, and diabetes, tested independent prediction of prolonged LOS (> 5 days); agreement between tools was assessed with Cohen’s κ. Results All four tests were associated with worse postoperative recovery, including longer hospital stay and delayed independent walking. Agreement between the criteria was generally low (Cohen’s κ 0.237–0.315), suggesting that the tools identified somewhat different subgroups. In the adjusted models, prolonged LOS was independently predicted by the 5-STS (adjusted odds ratio [aOR] 3.09, 95% CI 1.23–7.78) and SARC-F (aOR 2.79, 95% CI 1.03–7.57); the HGS-based definitions showed similar effect sizes without reaching significance. Conclusions Probable sarcopenia detected using simple, radiation-free bedside tools predicted an adverse postoperative course after lumbar disc herniation surgery, and lower-limb function (5-STS) was the strongest independent predictor. Because the tools showed only modest agreement, they are best used as complementary components of preoperative assessment rather than interchangeably, supporting a combined bedside strategy to identify patients at risk of difficult recovery.</p>