[Preoperative anal function assessment in sphincter-preserving surgery for rectal cancer: clinical significance and strategies].

Sphincter-preserving surgery has become the mainstream approach for mid-to-low rectal cancer, yet postoperative anal dysfunction (low anterior resection syndrome, LARS) occurs in 30%-50% of patients, significantly impacting quality of life. This review systematically elaborates the clinical value of preoperative anal function assessment (mainly digital rectal examination), proposing a multidimensional evaluation system integrating anatomical (including high-resolution anorectal MRI, 3D transrectal ultrasound and dynamic contrast-enhanced ultrasound), physiological (anorectal amnometry and anal electromyography), and neurological assessments (including Parks scale, Wexner score, MSK-BFI scale and LARS score), alongside innovative strategies such as artificial intelligence and gut microbiome analysis. We advocate incorporating preoperative functional assessment into quality control standards for sphincter preservation, promoting a paradigm shift from "anatomical preservation" to "functional preservation".