Lumbar hernia: diagnosis by CT.

Lumbar hernias occur in the region of the flank bounded by the 12th rib, the iliac crest, and the erector spinae and external oblique muscles. We present the CT findings of seven lumbar hernias: six traumatic (four secondary to postoperative flank incisions, one secondary to an iliac bone-graft donor site, one secondary to nonunion of an iliac fracture) and one spontaneous. Because CT portrays the anatomic relationships in this region so well, it may be the only radiographic procedure necessary to make the diagnosis of a lumbar hernia. Furthermore, it can be helpful in the assessment of symptomatic patients after flank incision, to differentiate postincisional muscular weakness and intercostal neuralgia from a lumbar hernia.