Exomphalos Major in Adults: A Treatment Modality

INTRODUCTION

Omphalocele (OC) is a congenital abdominal wall defect (CAWD) at the site of the umbilical ring with evisceration of the bowel covered by a three-layered membrane of peritoneum, Wharton's jelly, and amnion. It is associated with other congenital anomalies in up to 77% of patients. Omphalocele can be approximately divided into two groups: Minor and major (giant). In minor OC, the abdominal wall defect is relatively small (≤4 cm) and can be generally managed by primary closure. Giant OC is defined as abdominal wall defect of at least 5 cm and liver included.^1-4

Omphalocele occurs in 2.5/10,000 births and is associated with a high rate of mortality (25%) and severe malformations, such as cardiac anomalies (50%) and neural tube defect (40%). Male-to-female ratio is 1.5:1.

It is associated with an underdeveloped abdominal cavity and a high degree of viscera abdominal disproportion that prohibits save primary closure. Primary closure is often impossible and may lead to hypotension, decreased cardiac output, and respiratory failure.⁵ Operative treatments described in the literature are bridging the defect with dura mater, alloderm grafts, silo prostheses, skin flaps, prosthetic meshes, two bipedicled flaps, the use of tissue expanders, delayed staged repair,^3,6-14 and component separation technique (CST). The CST is based on enlargement of the abdominal wall surface by translation of the muscular layers without compromising the innervation and blood supply of the muscles.¹⁵ The disadvantages of most techniques are the risk of developing a large ventral hernia, multiple operations, and the use of prosthetic materials. However, staged closure can carry the same risk as primary closure by placing the abdominal contents under pressure.³

MATERIALS AND METHODS

Case Presentation

A 13-year-old female presented at our hospital with a swelling over abdomen. The swelling was present since birth and gradually increased in size to attain the present size. No pain was associated with the swelling, only a dragging sensation throughout the day. The size of the swelling remained same during walking or lying down. The delivery was a normal vaginal delivery and there were no associated congenital anomalies. On examination, a 25 × 25 cm spherical-shaped swelling with no tenderness and soft in consistency and irreducible was found (Figs 1A to C). The liver could be palpated in the swelling. Abdominal cavity appeared to be empty. A defect could be felt in the rectus sheath above the umbilical ring. Contrast-enhanced computed tomography abdomen showed evidence of anterior abdominal wall defect measuring 6.5 cm at level of D12 to L3 vertebrae, with completely herniated liver, antrum, and pyloric canal of stomach with proximal part of duodenum s/o Exomphalos major. No evidence of any congenital anomalies.

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Figs 1A to C:

(A) View of omphalocele from front; (B) horizontal view of omphalocele; and (C) view of omphalocele after retraction

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RESULTS

The patient was operated upon and the sac was opened which contained the liver. The abdominal cavity had decreased capacity (Figs 2A and B). The CST technique was used to increase the capacity of abdominal cavity. This was done to prevent chances of abdominal compartment syndrome when the liver was repositioned in the abdomen. Postoperative recovery was uneventful. Sutures were removed on 10th day. Regular follow-up was done. No evidence of any compartment syndrome or ventral hernia detected.

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Figs 2A and B:

(A) Opened sac showing liver; and (B) during closure

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DISCUSSION

The management of OC aims to reintegrate the herniated viscera in the peritoneal cavity and to repair the anterior abdominal wall. This reinstatement must be done without abdominal compression. So it is necessary, after reinstatement of viscera into the abdomen and before abdominal wall repair, to check whether there is any cyanosis, respiratory, and circulatory disorders.^2,6 The abdominal wall's closure with tension causes respiratory and circulatory disorders, intestinal necrosis, and infection, leading to death.² Different delayed closure techniques are reported, but there are a number of advantages for using the CST. First, avoiding the use of foreign material results in lower infection rates and reduces the formation of dense adhesions. Especially in contaminated conditions, the CST is extremely useful. Second, the CST has the advantage of minimal advancing skin flaps and thus reducing the infection risk. Third, reconstruction of the normal anatomy of the abdominal wall is achieved and gives excellent functional and cosmetic results. Lastly, in most cases, it is a one-stage procedure.⁵ The CST is a promising technique for repairing giant OCs without the use of prosthetic material⁵ in neonates, which can be applied to adults as well.

Surgical Technique¹⁶

The CST is based on enlargement of the abdominal wall surface by translation of the muscular layers without compromising the innervation and blood supply of the muscles. The arterial blood supply of the abdominal skin is mainly via the intercostal arteries and the perforating branches of the epigastric artery and branches of the pudendal artery.

The patient lies in a supine position. After incision of the skin just lateral of the scar tissue on the OC, the abdominal cavity is entered. The liver and bowels are dissected free from the skin and ventral abdominal wall. In this manner, the lateral border of the rectus abdominal muscle can be identified properly from the interior of the abdomen (Fig. 3A). The skin and subcutaneous fat are dissected free from the anterior rectal sheath and the aponeurosis of the external oblique muscle, to 3 to 4 cm lateral of the rectus sheath (Fig. 3B). The aponeurosis of the external oblique muscle is incised approximately 1 cm of the lateral border of the rectus abdominis muscle (Fig. 3C). The aponeurosis of the external oblique muscle is transected longitudinally over its full length. Transection includes the muscular part of the external oblique muscle on the thoracic wall. The attachment to the ribs must be dissected free to mobilize the rectus abdominis muscle to a maximum. Subsequently, the external oblique muscle is separated from the internal oblique muscle in the avascular plane between both muscles up to the mid-axillary line (Fig. 3D). Mobilization is essential because the fibrous interconnections between both muscles prevent optimal median shift of the rectus abdominal muscle. In this way, the rectus muscle can be shifted medially 5 cm at each side. The abdominal wall is closed in the midline with a running suture of a nonabsorbable or slowly absorbable suture material (PDS 2.0). The subcutis and skin are closed, and an umbilicus is created. After closure of the abdomen, the external oblique muscle is retracted laterally (Fig. 3E).

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Figs 3A to E:

The description of the CST in children with a giant OC: (A) A new born after epithelialization of the giant omphalocele; (B) dissection of the skin and subcutaneous fat from the abdominal wall muscles; (C) incision of the aponeurosis of the external oblique muscle 1 cm lateral of the rectus sheath; (D) separation of the external and internal oblique muscles; and (E) after closure of the abdomen, the external oblique muscle is retracted laterally

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CONCLUSION

The management of giant OCs remains a challenge for pediatric surgeons. Although the mortality rate is still high (up to 20%) in case of multiple congenital anomalies, surviving patients with OC achieve a state of health and quality of life comparable to that of general population peers. The newly introduced CST method seems to have a good outcome. The herniation rate is low, and prosthetic materials are not needed.⁵ Giant OC in an adult can be treated using the CST as in a neonate with favorable outcomes.