Preoperative sonographic prediction of intra-abdominal adhesions using sliding sign at repeat caesarean section at the University of Maiduguri Teaching Hospital, Nigeria: a prospective observational study

Abstract

Objective: To determine if the presence or absence of sonographic sliding sign preoperatively is a good predictor of the presence and type of intra-abdominal adhesions; and to determine the time taken to demonstrate this sign.

Design: A prospective, observational, triple-blind study using tests of diagnostic accuracy.

Setting: Single-centre tertiary health institution in north-east Nigeria.

Participants: 67 women in the third trimester scheduled for repeat elective caesarean sections (CS) had transabdominal sonography to determine the absence or presence and degree of sliding sign. The time taken to make these decisions were noted. Surgeons blinded to the ultrasound findings graded adhesions intraoperatively and comparison between sonographic and intraoperative findings made. Women who were scheduled for emergency CS were excluded.

Main outcome measures: Accuracy of preoperative ultrasound to determine no/mild, moderate and severe adhesions. Secondary outcomes were interobserver correlations and time taken to determine sliding.

Results: When classified as adhesion and no adhesion, the sliding sign demonstrated a sensitivity of 100.00% (CI₉₅ 85.18% to 100.00%), specificity of 100.00% (CI₉₅ 92.13% to 100.00%). In predicting presence of moderate intra-abdominal adhesions, a sensitivity of 65.0% (CI₉₅ 40.78% to 84.61%) and specificity of 82.98% (CI₉₅ 69.19% to 92.35%) was found. For predicting severe intra-abdominal adhesions, it had a sensitivity of 25.00% (CI₉₅ 0.63% to 80.59%) and specificity of 98.41 (CI₉₅ 91.47 to 99.96). Disease prevalence for mild, moderate and severe adhesions was 33.82% (CI₉₅ 22.79% to 46.32%), 29.85% (CI₉₅ 19.28% to 42.27%) and 5.97% (CI₉₅ 1.65% to 14.59%), respectively. Interobserver Cohen's kappa coefficient and PPA were 0.58 (CI₉₅ 0.39 to 0.76) and 58.82 (CI₉₅ 52.82 to 64.82), respectively. The mean duration to determine sliding sign was 7.56±2.86 s.

Conclusion: This study supports the role of transabdominal sliding sign in preoperative prediction of intra-abdominal adhesions in women with previous CS without significant increase in sonography duration. This information can encourage planning for CS by ensuring that surgeons of appropriate seniority are deployed to undertake anticipated complex operations.

Keywords: fetal medicine; prenatal diagnosis; ultrasonography.