JMA Journal

Figure 1. SOO patients were defined as those who had abdominal bloating symptoms and had CT findings of bowel obstruction at the stoma outlet and intestinal dilatation.
White arrow head: bowel obstruction at the stoma, ☆: dilated intestines.

Figure 2. The thickness of the abdominal rectus muscle (①) is defined as the thickness of thickest part of the abdominal rectus muscle, orthogonal to the long axis of the abdominal rectus muscle. The thickness of the AIW (②) is defined as the thickness of the AIW along the same line. All measurements are made using an axial computed tomography view at the level of the umbilicus.
SS, skin and subcutaneous; ARM, abdominal rectus muscle; OAM, external/internal oblique and abdominal transverse muscles.

Figure 3. A. The angle between the ileostomy and the AIW is defined as the inner angle between the long axis of the abdominal rectus muscle and the straight line passing through two midpoints of the proximal lumen (at the skin and peritoneum level) (red area). All measurements are made using an axial computed tomography view.
SS, skin and subcutaneous; ARM, abdominal rectus muscle; OAM, external/internal oblique and abdominal transverse muscles; SO, stoma outlet
B. A CT for a patient who developed SOO. The CT findings show the proximal lumen inclines to the medial side.
White arrow heads: stoma outlet, ☆: dilated intestines.

Figure 4. Comparison of the AIW between the stoma outlet obstruction (SOO) group and the non-SOO group.
AIW, angle between the ileostomy and the abdominal wall; SOO, stoma outlet obstruction.

Figure 5. Comparison of the AIW between the group undergoing surgery before ileostomy modification (LSa) and the group undergoing surgery after ileostomy modification (LSb).
AIW, angle between the ileostomy and the abdominal wall; LSa, group undergoing surgery before ileostomy modification; LSb, group undergoing surgery after ileostomy modification.

Figure 6. Two changes occur in the abdominal wall during pneumoperitoneum. (1) Due to the structural nature of the muscle fibers, the transverse abdominal muscle and the internal and external oblique muscles can extend laterally, but the abdominal rectus muscle cannot; thus, the skin and subcutaneous layer are displaced laterally from the muscular layer. (2) The angle between the long axis of the abdominal rectus muscle and the horizontal axis is increased. Due to these changes, the angle of the ileostomy outlet might tilt inward when the ileostomy is constructed under pneumoperitoneum.
SS, skin and subcutaneous; ARM, abdominal rectus muscle; OAM, external/internal oblique and abdominal transverse muscle; ST, stoma trephine.

Figure 7. CT images of the six patients who have developed SOO.
The transverse abdominal muscle and the internal and external oblique muscles extended laterally, but the abdominal rectus muscle did not under pneumoperitoneum. Thus, the skin and subcutaneous layer were displaced laterally from the muscular layer.
Yellow arrow: transverse abdominal muscle and internal and external oblique muscles, red arrow: abdominal rectus muscle, white arrow: skin and subcutaneous layer.