Overview
Definition:
Internal hernias, particularly those occurring at the Petersen's defect, represent a serious, potentially life-threatening complication following Roux-en-Y gastric bypass (RYGB)
The Petersen's defect is a potential space created between the jejunal mesentery and the posterior aspect of the gastrojejunostomy, through which bowel can herniate.
Epidemiology:
Internal hernias are reported in 1-5% of patients after RYGB
Petersen's hernias account for a significant proportion of these
The risk is higher in patients with longer biliopancreatic limbs, larger mesenteric defects, and longer operative times
Delayed presentation can occur months to years postoperatively.
Clinical Significance:
Internal hernias can lead to bowel obstruction, strangulation, ischemia, and perforation, necessitating urgent surgical intervention
Early recognition and timely management are crucial to prevent mortality and significant morbidity
Understanding the anatomy and operative techniques of RYGB is key to anticipating and managing this complication.
Clinical Presentation
Symptoms:
Intermittent or constant, severe, colicky abdominal pain, often diffuse but can be localized
Nausea and vomiting are common, often out of proportion to physical findings
Abdominal distension may be present
Changes in bowel habits, such as obstipation or diarrhea, can occur
Some patients report prior episodes of similar pain that resolved spontaneously (recurrent hernia).
Signs:
Tenderness on abdominal palpation, which may be localized or generalized
Rebound tenderness and guarding suggest peritonitis and possible strangulation
Bowel sounds may be hyperactive initially and then diminished or absent with obstruction
Tachycardia and hypotension may indicate hypovolemia or shock due to strangulation.
Diagnostic Criteria:
Diagnosis is primarily clinical, supported by imaging
A high index of suspicion in a patient with a history of RYGB presenting with acute abdominal pain, nausea, and vomiting is paramount
Definitive diagnosis is often made intraoperatively
There are no strict formal diagnostic criteria like those for some other conditions, relying heavily on clinical suspicion and investigation findings.
Diagnostic Approach
History Taking:
Detailed history of prior bariatric surgery, specifically RYGB, including date and any known intraoperative findings
Characterization of abdominal pain (onset, severity, radiation, relieving/aggravating factors)
History of nausea, vomiting, and bowel habit changes
Previous episodes of similar pain and their resolution are crucial clues.
Physical Examination:
Thorough abdominal examination focusing on tenderness, guarding, rebound tenderness, and masses
Auscultation for bowel sounds
Examination for signs of dehydration and shock (tachycardia, hypotension)
Digital rectal examination to rule out distal obstruction or associated pathologies.
Investigations:
Abdominal X-ray may show dilated loops of bowel and air-fluid levels in complete obstruction, but is often non-specific for internal hernia
CT scan of the abdomen and pelvis with oral and intravenous contrast is the imaging modality of choice
it can identify collapsed loops of bowel, clustered small bowel loops, engorged mesentery, and signs of strangulation or ischemia
It can also help identify the hernia defect
Laboratory tests include complete blood count (leukocytosis suggests strangulation), electrolytes, BUN, creatinine, and liver function tests.
Differential Diagnosis:
Other causes of small bowel obstruction post-RYGB include adhesions (less common than in open surgery), stomal stenosis, internal hernias at other sites (e.g., mesenteric defects around the jejuno-jejunal anastomosis, defect around the ascending limb), and volvulus
Pancreatitis, peptic ulcer disease, and appendicitis should also be considered.
Management
Initial Management:
Immediate resuscitation with intravenous fluids
Nasogastric tube decompression to relieve distension and reduce further intraluminal pressure
Pain management with analgesics
Broad-spectrum intravenous antibiotics if strangulation or perforation is suspected.
Medical Management:
Primarily supportive care during diagnostic workup and pre-operative stabilization
Antibiotics are administered for suspected complications
No specific medical management exists for the hernia itself
surgical intervention is required.
Surgical Management:
Urgent surgical exploration via laparotomy or laparoscopy is indicated for suspected internal hernia with signs of obstruction or strangulation
The primary goal is to reduce the herniated bowel
The Petersen's defect should be identified and closed
If bowel is viable, it is reduced
if necrotic, resection and anastomosis are performed
Closure of the Petersen's defect is typically done with non-absorbable sutures to obliterate the space
Some surgeons also advocate for closure of other potential mesenteric defects (e.g., around the JJ anastomosis).
Supportive Care:
Close monitoring of vital signs, urine output, and abdominal distension
Management of fluid and electrolyte balance
Nutritional support may be required, especially after bowel resection, with parenteral nutrition initially followed by gradual advancement of oral intake.
Complications
Early Complications:
Bowel strangulation, ischemia, and necrosis
perforation
anastomotic leak if bowel resection is performed
intra-abdominal abscess
prolonged ileus
wound infection
deep vein thrombosis
pulmonary embolism.
Late Complications:
Recurrent internal hernia if defect closure is inadequate or other defects are not addressed
adhesions leading to further obstruction
malnutrition
weight regain.
Prevention Strategies:
Meticulous closure of all mesenteric defects created during RYGB, particularly the Petersen's defect, using non-absorbable sutures
Some centers advocate for routine closure of the defect around the JJ anastomosis as well
Minimizing tension on mesenteric closure
Careful operative technique to avoid creating large defects
Patient education on recognizing symptoms and seeking prompt medical attention.
Prognosis
Factors Affecting Prognosis:
The speed of diagnosis and intervention is the most critical factor
Delays leading to bowel strangulation and necrosis significantly worsen the prognosis
The extent of bowel resection required also influences long-term outcomes.
Outcomes:
With prompt diagnosis and surgical management, outcomes are generally good
Patients who require bowel resection may have a more prolonged recovery and a higher risk of short bowel syndrome if extensive resection is needed
Mortality is low with timely intervention but can be significant if delayed.
Follow Up:
Postoperative follow-up includes monitoring for incisional healing, bowel function recovery, and nutritional status
Patients should be advised to report any recurrence of abdominal pain
Long-term follow-up should focus on maintaining weight loss goals and assessing for any late complications of bariatric surgery.
Key Points
Exam Focus:
Petersen's defect is a common site for internal hernia after RYGB
It is the space between the jejunal mesentery and the posterior gastrojejunostomy
Symptoms are typically severe abdominal pain, nausea, and vomiting
CT scan is the imaging modality of choice
Urgent surgical exploration and closure of the defect are indicated.
Clinical Pearls:
Always maintain a high index of suspicion for internal hernia in any patient with RYGB presenting with acute abdomen, especially if pain is severe and disproportionate to exam findings
Don't underestimate the value of a detailed surgical history
Laparoscopic repair is feasible but requires expertise, especially in cases of strangulation.
Common Mistakes:
Delayed diagnosis and treatment due to attributing symptoms to non-specific post-operative issues
Inadequate or absent closure of mesenteric defects during the primary RYGB procedure
Failure to consider internal hernia in the differential diagnosis of abdominal pain in RYGB patients
Insufficient bowel resection margins if strangulation is present.