Avoiding abdominal flank bulge after lumbotomy incision: cadaveric study and ultrasonographic investigation

The object of this study was to better define the relevant anatomy and innervation of the anterolateral abdominal wall musculature seeking to avoid abdominal wall complication after open donor nephrectomy. We dissected four cadavers and retrospectively assessed donor ultrasonographic imaging of anterolateral abdominal muscle atrophy after donor nephrectomy with a lumbotomy incision.

Anatomic study was performed on four cadavers using bilateral dissections. The 8th, 9th, 10th, 11th, and 12th (subcostal) intercostal nerves were dissected from the intercostal space to the rectus sheath. With the experience gained from anatomic study, we performed 40 living donor incisions 1.5 to 2 cm medial to the tip of 12th rib, toward the lateral border of the rectus muscle and the umbilicus. Donors were invited to the hospital at 1 year postoperative to examine abdominal wall complications. Ultrasonography (USG) was performed to assess the thickness of the abdominal wall muscles bilaterally to ascertain whether there was atrophy.

All distal intercostal nerves ran as multiple mixed segmental nerves, communicating with each other widely within the neurovascular plane. The thick 12th nerve was located at 1.5 to 2 cm medial and under the tip of the 12th rib, running to the suprapubic area. Postoperative USG confirmed that the mean percent thickness of the abdominal muscles of the operative side was not significantly different from the other side (P < .05).

Most significant intercostal nerve contributions to the anterolateral abdominal wall arise from T12. Damage to the intercostal nerves will be minimal if the lombotomy incision is performed above the safe line between the tip of the 12th rib and the umbilicus.