Accuracy of Computed Tomography in Identifying the Etiology of Small Bowel Obstructions in Virgin Abdomens at a Tertiary Care Military Treatment Facility

Abstract

Introduction

Small bowel obstructions (SBO) account for up to 50% of emergent laparotomies. Computed tomography (CT) aids in diagnosing SBO by identifying transition points and potential etiologies, though accuracy varies. SBO in a virgin abdomen (SBO-VA) presents unique diagnostic challenges. This study assesses CT accuracy in identifying SBO-VA etiologies in patients at a tertiary military treatment facility to help guide future management strategies.

Methods

This retrospective study reviewed SBO-VA cases from 2005-2021 with IRB approval. Patients were identified via ICD codes and included if ≥ 18 years with CT-confirmed SBO and no prior abdominal surgery. Demographics, imaging, and surgical findings were collected. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CT in identifying intraoperative etiologies were calculated.

Results

Of 80 patients with SBO and no prior abdominal surgery, 37 underwent operative management and were included in the final analysis. CT imaging showed 100% sensitivity for confirming obstruction and localizing a transition point. Diagnostic accuracy varied by etiology: sensitivity was highest for foreign bodies (100%). Strictures had a high sensitivity as well (80%), with a PPV (1.0) and specificity (100%) for foreign body, mass, and strictures. Among 17 non-operatively managed patients, adhesive disease was the most commonly presumed cause (56%), followed by partial obstruction or ileus (25%) with malignancy suspected in 2 (12%).

Conclusion

CT reliably identifies SBO and transition points but has variable accuracy in determining specific etiologies, underscoring the need for clinical judgment in nonoperative vs operative management in patients with SBO-VA.