Development and validation of a nomogram prediction model for patient selection in emergency day surgery of laparoscopic appendectomy based on preoperative and intraoperative immediate indicators

Some patients with acute appendicitis (AA) may be discharged in day surgery mode after emergency laparoscopic appendectomy (LA). However, objective and quantitative screening tools are currently lacking in clinical practice. This study aims to develop a nomogram prediction model for day emergency surgery of LA in AA patients based on preoperative and intraoperative clinical variables, thereby providing a reference basis for clinical patient selection for day surgery.

A single-center retrospective cohort study was conducted on 218 AA patients who underwent emergency day surgery of LA in our department between December 2021 and December 2023. Based on the length of hospital stay, the patients were divided into a day surgery group (≤48 h) and a conventional group (>48 h). Baseline characteristics, intraoperative status, and postoperative recovery were compared between the 2 groups. Preoperative and intraoperative variables with statistical differences were subjected to least absolute shrinkage and selection operator (LASSO) regression for feature selection, and a nomogram prediction model was constructed by multivariable logistic regression analysis. The discrimination, calibration, and clinical utility of the model were evaluated using receiver operating characteristic (ROC) curve, calibration plot, and decision curve analyses, respectively.

Compared with the conventional group, the day surgery group had significantly lower hospitalization costs (P<0.05), with no significant differences between them in the proportions of postoperative complications, 3-day and 30-day readmission rates, or reoperation rates. Univariate analysis revealed significant differences between the 2 groups in terms of age, Charlson comorbidity index (CCI), duration of disease peritonitis, white blood cell count, C-reactive protein (CRP), appendiceal diameter, appendiceal perforation, operative time, and intra-abdominal drainage tube placement (all P<0.05). LASSO regression screening and multivariable logistic regression analysis indicated that age (OR=0.444, 95%CI: 0.206 to 0.955, P<0.05), CRP (OR=0.072, 95%CI: 0.030 to 0.176, P<0.001), peritonitis (OR=0.448, 95%CI: 0.201 to 0.999, P=0.050), and operative time (OR=0.230, 95%CI: 0.107 to 0.496, P<0.001) were independent protective factors associated with emergency day surgery of LA. A nomogram prediction model was constructed based on these 4 variables. ROC curve analysis showed the model yielded an AUC value of 0.864(95%CI: 0.812 to 0.916), with favorable discriminatory ability, good consistency between predicted probabilities and actual occurrence rates, and sound clinical net benefit.

Emergency day surgery of LA is a safe and feasible option for selected patients with AA. Our constructed prediction model based on age, CRP, peritonitis, and operative time demonstrates favorable discrimination, calibration, and clinical utility, and may provide a quantitative reference for surgeons to select appropriate candidates for emergency day surgery of LA.