Development and Validation of a Nomogram for Predicting Postoperative Lower Extremity Deep Vein Thrombosis in Patients with Traumatic Spinal Fractures

Background Patients undergoing surgery for traumatic spinal fractures face a substantially elevated risk of postoperative lower extremity deep vein thrombosis (DVT). While generic risk assessment tools exist, a purpose-built model integrating spine-specific and readily available preoperative predictors is lacking. This study aimed to develop and internally validate a novel predictive model for this specific complication.

This retrospective cohort study analyzed data from 1,676 patients who underwent surgery for traumatic spinal fractures at a single center. All patients received standardized DVT surveillance. The cohort was randomly split into training (70%) and testing (30%) sets. Univariate and multivariable logistic regression with stepwise selection were used to identify independent predictors from 29 candidate variables. Model performance was evaluated by its discriminative ability (area under the curve, AUC), calibration (calibration curves and Hosmer-Lemeshow test), and clinical utility (decision curve analysis, DCA). A nomogram was constructed for clinical use.

The incidence of postoperative DVT was 14.26% (239/1,676). Six independent preoperative predictors were identified: prolonged bed rest > 72 hours (adjusted odds ratio [aOR] = 5.208), pre-existing lower extremity vascular disease (aOR = 2.938), elevated D-dimer (aOR = 1.582), elevated fibrinogen (aOR = 1.434), severe neurological impairment (ASIA grade A/B), and advanced age (aOR = 1.019). The model demonstrated robust discrimination (AUC: 0.891 training, 0.885 testing) and excellent calibration (Hosmer-Lemeshow p > 0.7), with high sensitivity (90.5– 91.2%) and moderate specificity (74.3–74.5%). Decision curve analysis confirmed its clinical utility across a wide range of threshold probabilities.

We developed and validated a parsimonious and clinically practical prediction model for postoperative DVT in traumatic spinal fracture patients. This tool, which leverages six preoperatively accessible variables, facilitates individualized risk stratification and could guide the implementation of targeted prophylactic strategies to improve patient outcomes. Competing Interest Statement The authors have declared that no competing interests exist. Funding Statement Yes Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Not Applicable The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study was conducted in accordance with the Declaration of Helsinki and received approval from the Medical Ethics Committee of the People's Hospital of Lichuan City (approval number: 2025003). Prior to analysis, all data were anonymised, and patient consent was deemed unnecessary due to the retrospective nature of the study. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Not Applicable I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Not Applicable I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Not Applicable Data Availability The datasets generated and analyzed during this study are not publicly available due to institutional data governance policies. However, de-identified data may be made available by the corresponding author upon reasonable request and with approval from the relevant ethics committee. - Abbreviations - AIC - Akaike Information Criterion - ALB - Albumin - APTT - Activated Partial Thromboplastin Time - ASIA - American Spinal Injury Association - AUC - Area Under the Curve - BMI - Body Mass Index - COPD - Chronic Obstructive Pulmonary Disease - CRP - C-Reactive Protein - DCA - Decision Curve Analysis - DVT - Deep Vein Thrombosis - FIB - Fibrinogen - GVIF - Generalized Variance Inflation Factor - Hb - Hemoglobin - IQR - Interquartile Range - aOR - Adjusted Odds Ratio - PLT - Platelet Count - PT - Prothrombin Time - WBC - White Blood Cell Count