Abdominal wall defect repair with component separation technique for giant omphalocele with previous relaxing incisions on the abdominal skin

Repair of large abdominal wall defects that cannot be closed primarily, as in the present case of giant omphalocele with prolapsed whole liver, is quite challenging. Ramirez et al. first reported the CST in 1990 as a surgical approach using autologous tissue to close large abdominal wall defects [6]. They performed the CST in an adult case of giant ventral incisional hernia. In recent years, it has been widely applied to large open wounds on the abdominal wall resulting from trauma, severe burns, and similar issues [7,8,9].

There are two approaches to bring the rectus abdominis to the midline in the CST: “anterior” and “posterior” [2]. In the presented case, “anterior” CST was selected for the following reasons. In the “posterior” approach, the posterior rectus sheath is incised from the abdominal cavity, and the dorsal surface of the rectus abdominis muscle is dissected laterally toward the transversus abdominis muscle. Then, an incision is made in the transversus abdominis muscle, and dissection between the transversus abdominis muscle and transversalis fascia is maintained to free the rectus abdominis muscles to the midline, which seems superior to the “anterior” approach in terms of preserving the blood flow of the abdominal wall. However, there was concern about the risk of liver injury associated with broad lysis of firm adhesion between the liver and peritoneum required in the “posterior” approach and the difficulty of maintaining a good dissecting layer between the transversus abdominis muscle and transversalis fascia followed by lysis in the present case.

The first report of the application of the CST to children was reported by Wijnen et al. in 2005 [10], followed by subsequent case series reports [11,12,13]. Eijck et al. summarized the postoperative outcomes of 11 infants with giant omphalocele (defect diameter: 6–9 cm) who underwent CST at 5–69 months of age (median age: 6.5 months), and reported that the thickness and motor function of the abdominal wall muscle in their patients were not markedly different from those of normal children after 38–84 months (median: 54 months) [11, 14]. Although CST can presumably be safely performed after 6 months of age according to a review of the relevant literature, we believe that surgery should be performed once sufficient development of the abdominal wall muscles and growth of the intra-abdominal volume have been achieved in the patient.

Regarding postoperative complications associated with the CST, although findings are limited to adult cases, the following meta-analysis data have been reported: rate of wound infection, 18.9%; hematoma, 2.4%; seroma, 2.4%; abdominal wall skin necrosis, 1.5%; and recurrence of ventral hernia, 18.2% [15]. There was some concern about abdominal skin necrosis in the present case due to the history of relaxing incisions at the abdominal wall in the neonatal period. The blood flow in the abdominal wall muscular layer is maintained by the superior and inferior epigastric arteries, and the perforating branches of those arteries through the rectus abdominis muscle are the feeding vessels of the abdominal wall skin [16]. The anterior CST requires extensive dissection between the skin and anterior sheath of the rectus abdominis muscle. In our case, we kept such dissection to a minimum to preserve the perforating branches. We also performed surgery while taking care to preserve additional blood flow from the superficial epigastric arteries.

In a further attempt to avoid impairment of the blood flow due to a sudden increase in intra-abdominal pressure, the pressure was managed by controlling the abdominal wall tension with muscle relaxants and monitoring the intravesical pressure. We tried to maintain the pressure at < 12 mmHg, which is the upper limit of normal, and ensured that it did not exceed 20 mmHg, which is the diagnostic criterion for abdominal compartment syndrome reported in the literature [4]. An increase in intravesical pressure was observed in the early postoperative period, so muscle relaxant dosages were increased to relieve the tension in the abdominal wall, thereby avoiding the occurrence of skin necrosis due to an impaired blood flow.

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