internal hernias due to gastric bypass surgery
Internal hernias due to gastric bypass surgery are more common after laparoscopic gastric bypass than after an open procedure.
Incidence after a Roux-en-Y gastric bypass may range between 1-16%. The presence of strangulation may be associated with a mortality rate exceeding 50% .
It is a particularly sinister complication with variable, non-specific clinical presentations. Most patients report a combination of postprandial abdominal pain, nausea and emesis . Patients may present at any time after surgery, however the majority are delayed, occurring after more than a month .
Physical examination findings are likewise non-specific, and may range from vague abdominal tenderness to palpation to peritonism .
It has been suggested that patients are more prone to internal hernias after laparoscopic Roux-en-Y gastric bypass than after an open operation because there are fewer adhesions to tether small-bowel loops and prevent them from herniating. In addition, patients who have greater degrees of weight loss after laparoscopic Roux-en-Y gastric bypass may be more prone to internal hernia because of loss of the protective, space-occupying effect of mesenteric fat .
Laparoscopic Roux-en-Y gastric bypass surgery produces three potential sites for internal hernia formation:
- at the defect in the transverse mesocolon through which the Roux limb passes (if it is placed in the retrocolic position)
- at the mesenteric defect at the enteroenterostomy
- behind the Roux limb mesentery placed in a retrocolic or antecolic position (retrocolic Petersen and antecolic Petersen type)
Postoperative complications which may present similarly after re-routing procedures include :
- anastomotic (staple line) leak
- marginal ulceration
- postoperative adhesions with obstruction
- less common cause of small bowel obstruction in this population