Case report: Complex retroperitoneal herniation after abdominoperineal resection

Abstract

INTRODUCTION

We describe the occurrence of a retroperitoneal hernia into the colonic mesentery after abdomoniperineal resection (APR) for rectal cancer.

PRESENTATION OF CASE

A 70 year old male presented with complete small bowel obstruction secondary to a complex retroperitoneal herniation. Operative repair was carried out with successful reduction of the hernia contents.

DISCUSSION

A review of the literature is reported concerning retroperitoneal hernia. This occurrence is rare in the adult. Management of the resultant pelvic space after APR is discussed. Closure of the pelvic peritoneum is helpful in avoiding this and other similar complications.

CONCLUSION

We believe this to be the first report of a small bowel obstruction secondary to this unusual hernia circumstance. Although rare, due vigilance and thorough imaging can lead to effective and timely management of this complication.

1. Case presentation

We present the case of a 70 year old male who was admitted to our institution with a small-bowel obstruction and evidence of internal hernia. Of note, he underwent an abdominoperineal resection (APR) for rectal cancer 2 years prior. Some months postoperatively he presented with a pelvic collection seen on CT scan, aspiration of which revealed chylous fluid. Following conservative management of this he recovered well. At this recent presentation, he complained of nausea, vomiting and on abdominal examination was found to have a right-sided fullness. CT scan of the abdomen demonstrated a sac-like configuration of small bowel loops in the mid-abdomen with concern for a closed loop obstruction (Fig. 1).

Fig. 1.

Contrast enhanced, coronally reformatted CT images demonstrating loops of small-bowel in a sac-like configuration with signs of a closed-loop obstruction.

The patient was taken for exploratory laparotomy and was found to have a significant retroperitoneal hernia with incarceration of most of his small bowel (Fig. 2). The location of the hernia was entirely midline, retroperitoneal, and involved the mesentery of the left colon. The apparent lead point was low in the pelvis, possibly consistent with development of a peritoneal flap after his APR. An extensive lysis of adhesions was conducted, eventually freeing the small bowel from this hernia sac. Postoperatively the patient did well and was resumed on a diet with no further obstructive symptoms.

Fig. 2.

Hernia sac at laparotomy. Much of the small intestine was incarcerated in this sac, with an apparent entry point in the pelvis.

2. Discussion

A hernia is defined as an abnormal protrusion of abdominal contents outside the normal peritoneal cavity.¹ While most general surgeons are familiar with hernias involving a musculoaponeurotic defect such as groin hernias, the occurrence of retroperitoneal herniation remains a rare event outside of the pediatric population and presents a unique diagnostic challenge.

Treitz first described and illustrated retroperitoneal hernias in 1857. Since this description, there have been multiple case reports and series detailing the occurrence of this phenomenon.² The most common site of retroperitoneal herniation is the left paraduodenal fossa. An accepted explanation for the occurrence of these retroperitoneal fossae relates to the formation of fusion folds within the peritoneum during embryonic development and intestinal rotation.

Acquired retroperitoneal herniation in adulthood is exceedingly rare with only a handful of cases being reported. These are often associated with traumatic injuries. Diagnosis can be difficult and in some cases may be impossible to obtain prior to laparotomy.³

The surgical literature holds scattered reports of traumatic or postoperative hematoma leading to the development of a potential space into which bowel may herniate. Hendrickson et al. reported a paracolonic hernia with development of obstruction after treatment of pulmonary embolism with anticoagulation led to spontaneous retroperitoneal hemorrhage.¹ Similarly, incarcerated hernia in a gunshot wound,³ hernia in a retroperitoneal hematoma after pelvic fracture,⁴ and herniation through unclosed defects in Gerota's fascia after nephrectomy⁵ have been described.

In our patient, development of a chylous collection after APR may have allowed a potential space to develop in the retroperitoneum associated with the left colonic mesentery. This then allowed the small bowel to herniate into the mesocolon thereby causing a complete small bowel obstruction.

Radiographic studies are important in the workup and evaluation of such cases. Characteristic findings of retroperitoneal herniation have been reported⁶ however it is of utmost importance to delineate whether or not the patient may have a closed-loop obstruction as was the case in our patient. Surgical repair simply requires adherence to basic surgical principles, with a goal being to restore intestinal integrity, and reduce the potential space. Care must be taken in the case of hernias involving the mesentery such that vasculature is preserved.

APR is a technically challenging procedure, which carries a risk of postoperative small bowel obstruction in up to 3% of patients.⁷ The question as to whether or not the pelvic peritoneum should be closed primarily has been the subject of some debate.⁸ Herniation below the pelvic floor with subsequent strangulation or herniation through the lateral colostomy gutter may occur and is associated with significant morbidity. For this reason some⁹ advocate not closing the peritoneum to avoid these events by leaving a larger and less constraining space. However, the frequent need for postoperative pelvic radiation is probably reason enough to close this defect in order to keep the small bowel out of the radiation field.⁸ It is our practice to close the pelvic peritoneum.

To the best of our knowledge this is the first description of the development of an incarcerated retroperitoneal hernia involving the left mesocolon following APR. Although this is an exceptionally rare occurrence, thorough imaging and due vigilance can identify and treat this entity in an effective manner.

Conflicts of interest statement

None.

Funding

None.

Ethical approval

We have obtained written consent from the patient and we can provide this should the editor ask to see it.

Author's contributions

Alkhoury involved in data collection, manuscript writing and literature review. Martin involved in literature review and editing and figures arrangement.