Laparoscopic management of small bowel obstruction caused by a Sigmoid Mesocolic hernia.

Internal hernias involve protrusion of viscera through the peritoneum or mesentery into a compartment in the abdominal cavity. Hernias occurring through the meso-sigmoid are rare and the most common presentation of this entity is an acute small intestinal obstruction. Pre-operative diagnosis is often difficult and the diagnosis is usually made at surgery. Traditionally, open surgery is used to manage a meso-sigmoid hernia. We report a patient with meso-sigmoid hernia causing intestinal obstruction managed successfully by the laparoscopic approach.

INTRODUCTION

Internal hernias result when one or more viscera extrude through an intra-peritoneal orifice but remain within the peritoneal cavity. The common internal hernias include paraduodenal, transomental, mesenteric defects and through the foramen of Winslow. Meso-sigmoid hernia (MSH) is a rare entity accounting for only about 5% of the internal hernias.[1] There are only two previous reports of laparoscopic repair of MSH in the surgical literature.[23] We report a case of MSH managed successfully by the laparoscopic approach and highlight the role of laparoscopy in the management of patients with intestinal obstruction.

CASE REPORT

A 54-year-old woman presented with left-sided lower abdominal pain and obstipation of three days duration. She did not have any nausea or vomiting. There was no history of similar previous episodes or any prior abdominal surgery. She was haemodynamically stable and had mild lower abdominal distention without tenderness or guarding. The bowel sounds were hyperactive. Haematological and biochemical tests were normal, except a mildly raised creatinine of 1.6 mg%. A plain abdominal X-ray showed a single dilated loop of small bowel in the left lower abdomen. An abdominal computed tomography (CT) scan showed dilated small bowel loops with a cut-off at the level of mid-ileum. She was given a trial of conservative treatment over the next two days, but as she failed to settle clinically, a surgical intervention was planned.

Laparoscopy was performed with the patient under general endotracheal anaesthesia, with an indwelling urinary catheter and nasogastric tube in place. The primary 10-mm port was placed supraumbilically by open method. Two other 5-mm ports were established on either side of the umbilical port. A preliminary diagnostic laparoscopy revealed collapsed large bowel and terminal ileum, whereas the proximal small bowel appeared grossly distended. Upon tracing the bowel back from the ileo-caecal junction, a loop of mid-ileum was found entering a 2-cm defect situated in the left leaf of the sigmoid mesocolon [Figure 1]. This loop reduced with the help of atruamatic bowel graspers was congested but non-gangrenous [Figure 2]. The hernial defect was closed laparoscopically with two interrupted intra-corporeal sutures of 2-0 silk (Mersilk, Johnson and Johnson, India) [Figure 3]. The fascia at the 10-mm port-site was closed and skin approximated with interrupted sutures. The patient required minimal post-operative analgesia, made an uneventful recovery and was discharged on the fifth post-operative day.

Figure 1

Defect in the sigmoid mesocolon.

Figure 2

Ischaemic loop of ileum herniated into the defect.

Figure 3

Closure of the mesocolic defect with intra-corporeal suturing.

DISCUSSION

The MSH although uncommon, is not extremely rare; Nihon-Yanagi et al., recently described a case of this type of hernia and reviewed 60 odd cases reported in the Japanese surgical literature.[4] Although most often reported in adults, MSH causing intestinal obstruction have been reported in the paediatric population.[5]

Three types of MSH are described:[1] (a) Inter-sigmoid hernia arising in the congenital fossa located in the attachment of the lateral aspect of the sigmoid mesocolon to the posterior abdominal wall; (b) Trans-meso-sigmoid hernia occurring when the loops of bowel pass through a defect in the sigmoid mesocolon; and (c) Intra-sigmoid hernia that results when the defect in the sigmoid mesocolon affects only the left leaf of the peritoneum and the hernial sac lies within the sigmoid mesocolon (as seen in our patient). The precise aetiology of MSH is unknown and several hypotheses have been suggested. Menegaux postulated that the defect occurred during the developmental enlargement of an inadequately vascularised area, whereas Federschmidt stated that the hernial defect represents a partial regression of the dorsal mesentery during development.[6] Perez-Rouiz documented a case of MSH presenting a few months after a laparoscopic surgery.[7] They theorised that the pneumoperitoneum might have caused the defect to open up, resulting in subsequent intestinal obstruction. Although small bowel is the most common content in the MSH, a case of cystadenoma of the uterine adnexa protruding through the meso-sigmoid defect has been described.[8]

An MSH usually remains quiescent and intestinal obstruction is often its presenting feature. In patients presenting with small intestinal obstruction, absence of an obvious external hernia, history of tuberculosis (pointing to a likely stricture) or of previous surgery (suggesting adhesions) should alert the clinician for the possibility of an internal herniation as the cause. The CT appearances indicative of internal herniation consist of medial displacement of the colon by herniated intestinal loops and bird-beak appearances of the afferent and efferent intestinal segments. It has been suggested that such a bird-beak appearance in the pelvis that is centred towards the medial side in a patient with intestinal obstruction is highly suggestive of an MSH.[9] Nevertheless, in a majority of patients, the diagnosis of MSH is likely to be established only at surgery.

Patients with small intestinal obstruction not responding to conservative therapy require surgery. If an internal herniation is suspected, the surgery should be prompt, as strangulation and necrosis of the hernial contents is likely to ensue if the surgery is delayed. Traditionally, such a treatment is undertaken by open surgery in which the contents are reduced from the hernial defect, and resected if necrotic and the defect is closed. The role of laparoscopy in patients with intestinal obstruction is being increasingly recognised.[10] The intervention is preferably undertaken when the acute episode has resolved and the abdominal distention settled down. However, in experienced hands, there is a definite role for diagnostic laparoscopy in selected patients during acute small bowel obstruction, provided that certain tenets are adhered to. The first port must be placed by open method, taking precautions to safeguard the distended bowel. The bowel loops must be traced backwards from the collapsed segment and gentle handling with atraumatic graspers is essential. Caution must be exercised in reducing the loop entering the defect, which may have to be stretched or widened, thus safeguarding the structures (such as the blood vessels) at its periphery. Suspicion of intestinal gangrene and necessity for resection should prompt conversion. Similarly, a low threshold for conversion should be maintained when inadequate intra-abdominal space risks injury to the distended bowel during its manipulation.

In conclusion, this case report underscores the diagnostic as well as therapeutic roles of laparoscopy in patients with acute intestinal obstruction and highlights the feasibility and safety of this approach even in a rare pathology such as an MSH.