Internal hernia following laparoscopic anterior resection for cancer: higher prevalence than expected of an under-reported complication.

BACKGROUND: Internal hernia (IH) after laparoscopic colorectal surgery is a potentially severe complication. It may go undiagnosed in patients having their abdominal CT scan during oncologic follow-up. We evaluated the occurrence of IH on CT scans after laparoscopic curative resection for rectal cancer (LRRC) and routine closure of the mesenteric defect. METHODS: Data from 189 consecutive patients undergoing elective curative LRRC in a 14-year period (June 2005-june 2019) were prospectively collected. Only patients with abdominal CT scans, performed as routine oncologic follow-up, between 3 months and 7 years post-operatively were included in the study and reviewed by a surgeon and a radiologist. RESULTS: A total of 161 patients were eligible for the study with a median age of 69 years (IQR: 59-77) at surgery. They had abdominal follow-up CT scans at a median of 39.5 months (IQR: 12.8-62.7) after surgery. The prevalence of IH was 11.2% (18/161 patients). Of the 18 patients, 15 (83.3%) were fully asymptomatic, 2 (11.1%) reported chronic abdominal discomfort (including mostly nausea and colicky pain) during their oncologic follow-up (however, IH was not suspected neither prompted additional investigations), and 1 (5.6%) was reoperated elsewhere for IH and acute small bowel obstruction. CONCLUSIONS: IH following LRRC is not uncommon, with a prevalence > 10% in our experience. Most of these patients remain fully asymptomatic, but in a few patients, IH might be responsible for some symptoms or require reoperation. Awareness of this complication is important, given the potential risk of acute small bowel obstruction.