Preoperative undernutrition in older people with adult spinal deformities is associated with worse postoperative sagittal vertical axis.

Abstract

The impact of preoperative nutritional status on postoperative clinical outcomes in older adults undergoing surgery for adult spinal deformity (ASD) remains unclear. This study aimed to investigate the association between preoperative nutritional status and postoperative clinical and radiological outcomes in patients undergoing surgery for ASD. A total of 117 patients (mean age: 73.3 ± 5.4 years; 77 women) who underwent fusion of ≥3 vertebrae for ASD were retrospectively enrolled from a multicenter database. Nutritional status was assessed using the Controlling Nutritional Status (CONUT) scale, which is based on serum albumin, total lymphocyte count, and total cholesterol levels, with scores ranging from 0 to 10. Patients were classified into two groups according to their nutritional status: the undernutrition (UN) group (CONUT score ≥2) and the normal nutrition (N) group (CONUT score 0-1). Multivariate regression analysis was performed to identify independent predictors of postoperative sagittal alignment deterioration. The N group included 67 patients, while the UN group included 50 patients. At 2 years postoperatively, the UN group exhibited a significantly greater sagittal vertical axis (SVA) (56.5 ± 47.5 mm vs. 44.2 ± 40.2 mm, P = 0.007) and a smaller spino-femoral angle (SFA) (194.4 ± 19.3° vs. 202.6 ± 19.2°, P = 0.029) compared to the N group. Multivariate analysis revealed that preoperative undernutrition was an independent predictor of postoperative SVA deterioration. Preoperative undernutrition was associated with increased SVA and decreased SFA at 2 years postoperatively in older patients undergoing surgery for ASD. These findings suggest that preoperative nutritional status may influence postoperative outcomes in this population, highlighting the importance of nutritional screening and intervention prior to surgery.