Background <p>With an increasingly aging population, the number of older people undergoing elective spinal surgery is growing. Accurate assessment of a patient’s preoperative physiological status is particularly important to reduce surgical and anesthetic risk. This study aims to investigate the relationship between a brief preoperative frailty assessment and the occurrence of adverse postoperative outcomes in elective spinal surgery in older adults.</p> Methods <p>This is a prospective cohort study. The participants selected for the study were older adults undergoing elective spinal surgery at Shengjing Hospital of China Medical University. A total of 231 geriatric patients aged 65 years or older were assessed for preoperative frailty using the FRAIL scale, a brief frailty screening scale that covers five main aspects: fatigue, resistance, mobility, disease status, and weight, within 1 week before surgery. A follow-up was conducted within 30 days after surgery to obtain information about postoperative recovery. The primary outcome indicator was the occurrence of postoperative complications. Complications of interest included postoperative infections (respiratory, urinary, and surgical site infections), cardiovascular complications, blood transfusions, electrolyte disturbances, and problems with postoperative feeding. Secondary outcome indicators were prolonged hospital stay and adverse postoperative course (CCI above the 75th percentile). Independent risk factors associated with adverse postoperative outcomes were identified mainly by univariate and multivariate logistic regression.</p> Results <p>The study period was from August 12, 2021, to August 10, 2022. A total of 207 patients were eventually analyzed in this study, of whom 101 (48.8%) were male and 106 (51.2%) were female. The median age of the cohort was 69 (Interquartile Range (IQR): 67–72) years. Preoperative frailty assessment resulted in 30 (14.5%) being healthy, 121 (58.5%) being prefrail, and 56 (27.1%) being frail. A total of 65 (31.4%) of the 207 patients experienced postoperative complications. In a multifactorial analysis, frailty (score ≥ 3) (OR, 4.80; 95% CI, 1.1-20.96) and ASA classification ≥ 3 (OR, 2.53; 95% CI, 1.23–5.21) were independent risk factors for the development of postoperative complications. ASA classification ≥ 3 (OR, 2.21; 95% CI, 1.046–4.69) was significantly associated with a prolonged hospital stay. Patients with frailty (score ≥ 3) (OR, 6.426; 95%CI, 1.13–36.69) or ASA classification ≥ 3 (OR, 4.10; 95% CI, 1.71–9.83) were at increased risk of adverse postoperative course (CCI above the 75th percentile).</p> Conclusions <p>In geriatric elective spine surgery, preoperative assessment using the Frailty Screening Scale can help identify patients at potentially higher risk for postoperative adverse events. However, further high-quality studies are warranted to investigate the reliability of brief frailty assessments in predicting postoperative outcomes.</p> Trial registration <p>This study was initially registered in the Chinese Clinical Trial Registry on 8/8/2021 under the registration number ChiCTR2100049677.</p>