Ultrasonography of the abdominal wall before and after laparotomy in cows.

The ultrasonographic appearance of the normal abdominal wall in the flank region was investigated before and after exploratory laparotomy in five cows (group A). The results were compared with those after surgical correction of left displaced abomasum in 10 cows (group B) and of caecal dilatation in another 10 cows (group C). We hypothesized that in group C and group B, wound healing would be impaired because of the higher risk of complications compared to group A. A 10.0 MHz linear transducer was used to examine the abdominal wall immediately before exploratory laparotomy and for 10 days (groups B, C) or 30 days (group A) postoperatively. The thickness of the individual layers of the abdominal wall was determined. The skin and the individual muscle layers could be well differentiated via ultrasonography in all the cows preoperatively. In group A, the total thickness of the abdominal wall ranged from 2.80 to 3.40 cm; the skin and the subcutaneous tissues were 0.60 to 0.80 cm, the external abdominal oblique muscle 0.50 to 0.70 cm, the internal abdominal oblique muscle 0.50 to 0.70 cm, the transverse abdominal muscle 0.50 to 0.75 cm, and the transverse fascia and peritoneum were 0.20 to 0.30 cm. Groups B and C had similar findings. There was no significant difference in the course of healing, the thickness of the abdominal wall or thickness of the individual layers during healing among the three groups of cows. Features of healing included subcutaneous emphysema in 19 cows, seroma in 19 and haematoma in 2 cows. However, the occurrence of these events did not differ significantly among the three groups. Ultrasonographic examination of the wound on day 10 postoperatively was unremarkable in 24 cows. A seroma was still present on day 15 postoperatively in one cow of group B.