[Evaluation of sarcopenia and bioimpedance parameters related to muscle strength in the pre-operative consultation for spinal surgery].

Introduction: sarcopenia is characterized by loss of muscle mass and function. Spinal disorders are a risk factor for muscle deterioration. In turn, sarcopenia is associated with adverse outcomes in the postoperative period of spinal surgery. Objectives: to evaluate sarcopenia and the relationship of muscle strength with bioimpedance parameters in the preoperative consultation. Material and methods: cross-sectional observational study. Muscle strength (dynamometry) and body composition (bioimpedance spectroscopy) were measured as part of the functional assessment of nutritional status. Sarcopenia was defined according to the European Working Group on Sarcopenia in Older People 2019 (EGWSOP2) and dynapenia/myopenia in the case of low strength or isolated muscularity. The relationship between the dynamometry values and the bioimpedance variables was summarized with the Spearman's coefficient. Results: twenty-two patients were included. The median (IQR) age was 60 years (43-65) and 72 % were women. The most frequent diagnosis and surgical procedure was spondylolisthesis (45 %) and posterior fixation (50 %). The mean body mass index (BMI) was 28.3 (± 4.59) kg/m2. The presence of sarcopenia, dynapenia and myopenia was 18.2 %, 13.6 % and 22.7 %, respectively. Dynamometry was correlated with lean tissue index: 0.61 (p 0.002); body cell mass: 0.68 (p 0.000); appendicular skeletal muscle: 0.49 (p 0.021); phase angle: 0.46 (p 0.031); and resistance index 200/5 kHz: -0.47 (p 0.028). Conclusion: muscle strength is correlated with bioimpedance parameters. Sarcopenia, dynapenia and myopenia are frequent and objectifiable in the preoperative spinal surgery consultation.