[Construction of a frailty index for cervical kyphosis and analysis of its clinical value].

<b>Objectives:</b> To develop a cervical kyphosis frailty index (CK-FI) and explore its clinical value in identifying high-risk patients undergoing cervical kyphosis correction surgery. <b>Methods:</b> In this retrospective case series, clinical data from 53 patients who underwent cervical kyphosis correction at the Department of Orthopedics, Beijing Tiantan Hospital, Capital Medical University, between January 2019 and December 2023 were analyzed. All patients had a minimum follow-up of 12 months. There were 27 males and 26 females, with an age of (53.4±14.5) years (range: 15 to 83 years). Demographic data, comorbidities, laboratory results, radiographic parameters, and functional assessments were collected. Fifteen key indicators related to physiological reserve and stress tolerance in cervical kyphosis patients were identified via Pearson correlation analysis to establish the CK-FI. Differences in demographic characteristics, clinical outcomes, postoperative complications, and length of hospital stay among CK-FI subgroups were analyzed using independent sample <i>t</i>-tests, one-way ANOVA,Wilcoxon signed-rank tests, Mann-Whitney <i>U</i> tests, Kruskal-Wallis tests, and chi-square or Fisher's exact tests. Binary logistic regression was employed to determine independent risk factors for postoperative complications. Receiver operating characteristic (ROC) curve analysis was used to assess the predictive performance of CK-FI for postoperative complications. <b>Results:</b> Based on CK-FI scores, patients were classified into non-frail (CK-FI<0.3), frail (0.3≤CK-FI≤0.5), and severely frail (CK-FI>0.5) groups. The 30-day postoperative complication rate was 26.4% (14/53). Both univariate and multivariate analyses indicated that frailty (<i>OR</i>=6.892, 95%<i>CI</i>: 1.239 to 38.353, <i>P</i>=0.028) and severe frailty (<i>OR</i>=10.313, 95%<i>CI</i>: 1.877 to 56.659, <i>P</i>=0.007) were independent risk factors for postoperative complications. ROC analysis revealed that CK-FI had an area under the curve of 0.777 (95%<i>CI</i>: 0.637 to 0.917, <i>P</i>=0.001), with a specificity of 70.3% and a sensitivity of 81.3% in predicting postoperative complications. <b>Conclusions:</b> The CK-FI serves as a valuable tool for early detection of high-risk patients with cervical kyphosis, aiding in individualized perioperative management, optimizing preoperative preparation, reducing postoperative complications, and ultimately improving patient outcomes.