You get called to see a consult in the middle of the night. It is a middle-aged woman with a bariatric history, and she says her stomach is smaller but doesn’t know the name of the operation. She developed worsening abdominal pain after dinner and it’s been getting worse. She’s not peritonitic, but she’s clearly in discomfort. Is it cholecystitis, diverticulitis, pancreatitis, marginal ulcer, or an internal hernia? What do you do? Join Drs. Matthew Martin, Adrian Dan, and Paul Wisniowski on a discussion about initial evaluation and management of bariatric patients with internal hernias. 

Show Hosts:
Matthew Martin
Adrian Dan
Paul Wisniowski

Video companion: https://app.behindtheknife.org/video/clinical-challenges-in-bariatric-surgery-internal-hernia

Show Notes
1.     Initial Evaluation
a.     Focused history and physical, labs, and imaging
                                      i.     Presenting symptoms may vary and include: nausea, emesis, and abdominal pain ranging from vague to severe.  
                                     ii.     A basic lab panel can aid in developing the diagnosis and guide resuscitation.
                                    iii.     CT of the abdomen and pelvis with IV and oral contrast can assist in identifying intra-abdominal pathology
                                    iv.     Reviewing the previous operative report is beneficial to have a framework of the anatomy, i.e. type of bariatric surgery, and configuration of small bowel limbs (ante- vs retro-gastric and ante- vs retro-colic).
1.     According to a 2019 study, 40-60% of closed defects had reopened at time of re-exploration 
                                     v.     If the patient is peritonitic with abdominal pain, they should be treated similarly to any patient with an acute abdomen with emergent exploration.
b.     CT Imaging 
                                      i.     A mesenteric swirl sign with twisting of the soft tissue and mesenteric vessels with surrounding fat attenuation has been shown to have a sensitivity of 78-100% and specificity of 80-90%. Other findings include: a Bird’s beak, dilation of roux or biliopancreatic limbs, SMV narrowing, and displacement of JJ limb to the RUQ and can be used to support the diagnosis of internal hernia
                                     ii.     An experienced radiologist familiar with bariatric anatomy has been shown to have a positive predictive value to 81% and negative predictive value to 96% at radiologically diagnosing internal hernia. 
                                    iii.     A CT scan can provide insight for a suspected diagnosis but it cannot rule out internal hernia
c.      Nasogastric/Esophageal Tube
                                      i.     Use judiciously based on patient’s presenting symptoms
                                     ii.     Placement should be done by the surgical team 
                                    iii.     This may mitigate the risk of aspiration during intubation.
2.     Operative Management
a.     Entry should be dependent on the comfort of the operating surgeon. 
                                      i.     Veress entry into the abdomen with dilated bowels may lead to increased injuries. 
                                     ii.     Optiview allows for direct visualization of each layer of the abdominal wall. Focusing on twisting the trochar and limiting perpendicular pressure. 
                                    iii.     Hasson entry also allows for direct visualization but may be limiting in bariatric patients with thick abdominal walls
b.     Exploration – a systematic approach
                                      i.     Start with evaluation of the gastric pouch and run the roux limb to the jejunojejunostomy, and examine Petersen’s and mesojejunal defects. 
                                     ii.     Follow the biliopancreatic limb to the ligament of Treitz
                                    iii.     Lastly, identify the terminal ileum at the sail of Treves and run backwards to the jejunojejunostomy
                                    iv.     This will allow for examination of all possible defect and possible intussusception at the jejunostomy
c.      Defect Management
                                      i.     All defects should be closed, with studies demonstrating reduced rates of internal hernia when defects are closed with a running suture. There is no strong evidence to support the use of a specific suture material.
1.     The use of suture is superior to other methods of closure such as metallic clips, fibrin glue, mesh, or abrasive pads.
2.     A barbed suture can be considered.
d.     In a patient with unfavorable anatomy or those unable to tolerate pneumoperitoneum surgeons should consider early conversion to open exploration 
3.     Postoperative Care
a.     Patients are started on ERAS protocol with limited narcotic use, same day mobilization, early oral nutrition with advancement, and no nasogastric tubes or foley catheters
b.     Patients with bowel resection and those with suspected postoperative ileus may benefit from judicious advancement of diet.
4.     Pregnancy
a.     Pregnant patients with history of anastomotic bariatric surgery are at increased risk of internal hernia especially in 3rd trimester due to loss of intra-abdominal space
b.     Evaluation of a pregnant patient should include abdominal imaging. 
                                      i.     In a non-acute setting, an MRI abd/pelvis can be considered. 
                                     ii.     Patients with abdominal pain presenting to the Emergency Department should undergo CT imaging.
                                    iii.     The risk of radiation to a fetus, especially beyond the 1st trimester, is limited. Based on the CDC guidelines, a human embryo and fetus are sensitive to ionizing radiation at doses greater than 0.1Gray. The amount of radiation from a typical CT range from 0.015 to 0.034Gray depending if it is multiphasic or not; well below the guideline level.
c.      It is important to discuss with women of child bearing age the risk of internal hernia during pregnancy with anastomotic bariatric surgery
5.     Outpatient Presentation
a.     Half of patients with internal hernia will present in outpatient setting often >6 months after initial operation with complaints of intermittent nausea, vomiting, and abdominal pain
b.     Workup includes: CT abd/pelvis with IV and oral contrast, Upper GI series, EGD, and a RUQ ultrasound based on their symptoms
c.      If diagnostic testing is equivocal, proceed with diagnostic laparoscopy to mitigate the risk of internal hernia with bowel ischemia.

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