Objective: We retrospectively assessed computed tomography (CT) scans to determine degree of anterolateral abdominal muscle atrophy in patients who underwent infrarenal aortic repair with 2 kinds of incisions for the extraperitoneal approach.
Methods: CT scans obtained before surgery and final scans obtained 2 to 100 months after surgery were assessed in 12 patients with paramedian incision (PM group) and 27 patients with flank incision (F group) who could be followed up at our hospital. We considered muscle thickness before surgery on the incision side to be 100% thickness (baseline value), and we calculated, by measuring the incision side after surgery, the corrected percent thickness (CPT%), which represents percentage of remaining muscle thickness that has escaped incision-induced atrophy. CT scans obtained at the level of the third (L3) and fifth (L5) lumbar vertebrae and the center of the sacrum (S) were selected for CPT% measurement.
Results: Duration from surgery to final CT scan was 2 to 65 months (mean +/- SD, 34.33 +/- 21.38 months) in PM group and 3 to 96 months (27.85 +/- 20.74 months) in F group. In PM group, mean CPT% values of the rectus abdominis muscle were 55.83 +/- 21.65% at L3, 35.50 +/- 10.79% at L5, and 31.92 +/- 11.00% at S; these values were statistically much smaller than baseline (P <.01). Mean CPT% values of the lateral abdominal muscles were not statistically different from baseline. In F group, mean CPT% values of the rectus abdominis muscle were 82.19 +/- 23.15% at L5 and 64.41 +/- 31.34% at S; these values were statistically smaller than baseline (P <.01). Mean CPT% values of the lateral abdominal muscles were 87.59 +/- 22.30% at L3 and 84.59 +/- 26.90% at L5; these values were statistically smaller than baseline (P <.05).
Conclusions: Paramedian incision induced severe rectus abdominis muscle atrophy. Although flank incision induced various degrees of atrophy in both muscles, some patients had no muscle atrophy. These data indicate that further anatomic investigation into the relation between flank incision and abdominal wall innervation may contribute to prevention of muscle atrophy after flank incision.