Distinguishing abdominal wall denervation injury from normal anatomy via cross section imaging.

PURPOSE: To identify objective CT-based measurements of abdominal wall denervation injury and establish an imaging-based assessment framework for abdominal wall denervation syndrome.

METHODS

CT scans from patients with unilateral denervation, full-thickness hernia, or intramuscular hernia were retrospectively reviewed using TeraRecon’s Aquarius software. Measurements from the symptomatic side were compared with the contralateral normal side. Axial assessments included EO and TA lengths and abdominal wall thickness, while coronal assessments included muscle length only. Axial slices were also used to evaluate muscle area, mean attenuation in Hounsfield units (HU), and muscle composition.

RESULTS

At the point of maximal bulging, denervation was marked by enlargement of the lateral abdominal wall, with significantly increased EO (p < 0.001) and TA (p < 0.001) lengths, and decrease of the abdominal wall thickness when compared to the contralateral normal side; muscle composition also showed greater fat replacement (p = 0.04). Relative to full-thickness and intramuscular hernias, denervation likewise led to increasing length of the EO (p = 0.001) and the TA (p < 0.001); and decreasing measurements of thickness (p < 0.001). Coronal views confirmed EO and TA lengthening of the denervated abdominal wall (p < 0.001).

CONCLUSION

Abdominal wall denervation syndrome can be radiologically presumed by a lateral abdominal wall bulge without any muscular defect (hernia). Denervated muscles appear longer, thinner, and show greater intramuscular adipose tissue compared with the contralateral healthy side. These objective CT-based features may serve as imaging criteria to aid the diagnosis of abdominal wall denervation syndrome.