Introduction. Incisional lumbar hernia is still a diagnosis problem of the first magnitude. The diagnosis of incisional hernias outside the midline remains a challenging procedure. 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. CT portrays shows the anatomic relationships in this region so well and it may be the only radiographic procedure necessary to make the diagnosis of a lumbar incisional hernia. Aim of the study. Objective evaluation of the alterations in body image and configuration of patients who underwent urological surgery via a flank incision. Materials and methods. Eligible for study were 7 patients who underwent urological surgery via lumbar incision for renal diseases. Preoperative and postoperative abdominal computerized tomography were used for evaluation. We evaluated the objective results using computerized tomography. Results. Over a 12-month period, lumbar hernias were detected with CT in seven patients, all had flank incisions, six of them with detectable flank bulge and one without. In 3 patients diffuse and large hernias were found, in two patients superiorly located hernias, which are immediately palpable below the 12th rib and subsequently thought to originate from the superior lumbar triangle, and in two patients inferiorly located hernias palpable just above the iliac crest and subsequently thought to originate from the inferior lumbar triangle. The mean age was 58 years (range 30-76); five women and two men. Of these, two were asymptomatic and five were symptomatic. All seven lumbar hernias detected on CT were on the left side. Two of them contained extraperitoneal fat and five contained bowel (descending colon or sigmoid colon). Six of the postincisional hernias showed disruption of normal muscle layers. In one case only the external oblique muscles were intact. In a high postincisional hernia there was a disruption of the intercostal muscles. Conclusions. CT can be helpful in the assessment of symptomatic patients after flank incision, to differentiate postincisional muscular weakness and intercostal neuralgia from a lumbar hernia and is able to delineate muscular and fascial layers, a defect in one or more of these layers, and the presence of herniated fat and/or viscera. Computerized tomography is the diagnostic method of choice and is recommended in all patients with a bulge after a flank incision.