Comparison of the efficacy between transperineal ultrasound and endoanal ultrasound in diagnosing obstetrics anal sphincter injury / 中华超声影像学杂志

ABSTRACT

Objective:To study the agreements between transperineal ultrasound (TPUS) and endoanal ultrasound in assessing obstetrics anal sphincter injury (OASI), and to analyse the diagnostic efficacy of OASI in predicting AI relationship between OASI and anal incontinence (AI).Methods:A total of 217 women were prospectively recruited from the clinic in the Second Xiangya Hospital of Central South University from January 2021 to May 2022. Symptoms of AI were determined using the St Mark′s Incontinence Score (SMIS). TPUS and EAUS were performed by the same operator with the same machine on every participant for detecting OASI OASI grades 3a, 3b, 3c, and 4 were performed according to the extent of the injuries in the anal sphincter complex. The angle of the defect in the external anal sphincter (EAS) was measured. A "significant EAS defect" was diagnosed as a defect affecting at least 2/3 of the length of the EAS with a defect angle of ≥30° in each slice.Ultrasound findings were compared between the two methods. The diagnostic efficacy of "ultrasound OASI" in predicting AI was analysed by logistic regression.Results:Of 217 women, twenty-eight (12.9%) suffered from AI with SMIS ranging from 5~20(11.9±4.5). On TPUS, 79 (36.4%) cases were suspected of OASI, that was 50 OASI 3a, 13 OASI 3b, and 16 OASI 3c/4. On EAUS, 78 (35.9%) cases were suspected of OASI that was 23 OASI 3a, 22 OASI 3b, 15 OASI 3c, and 18 OASI 4. Twenty-four "significant EAS defects" were diagnosed by TPUS and twenty-eight by EAUS, TPUS had excellent agreement with EAUS (weighted Kappa=0.91, P<0.001). Logistic regression analysis showed that "ultrasound OASI" was associated with AI symptoms. ROC curve analysis showed that the area under the curve (AUC) was 0.92, 0.87, 0.89, 0.92 for TPUS OASI 3b+ , EAUS OASI 3b+ , TPUS "Significant EAS defect" , and EAUS "Significant EAS defect" for predicting AI, respectively. Conclusions:TPUS has good agreement with EAUS in detecting OASI. OASI 3b+ and "significant EAS defect" on TPUS and EAUS had good performance in predicting AI symptoms.