Acute Internal Pelvic Hernia: A Complex Diagnostic Challenge
Internal hernia is a rare cause of small bowel obstruction. It may be congenital, resulting from anomalies in peritoneal attachments or acquired after inflammation, surgery, or trauma. It is defined as the protrusion of abdominal viscera, most commonly small bowel loops, through a peritoneal or mesenteric defect into a compartment within the abdominal or pelvic cavity. Internal abdominal hernias constitute 0.5% to 5.8% of cases of mechanical small bowel obstruction. Acute mechanical small bowel obstruction is a common condition needing surgical evaluation; the most common causes are postoperative adhesions, neoplasms, and abdominal wall hernias. It accounts for 2–4% of emergency presentations, approximately 15% of inpatient admissions, and 20% of emergency surgical operations for acute abdomen. The diagnosis of internal hernia causing acute small bowel obstruction is often challenging due to its rarity and nonspecific symptoms. 

A 42-year-old female airline cabin crew member presented with a 1-day history of colicky lower abdominal pain and bilious vomiting. She reported a history of 1 previous episode of abdominal pain and vomiting many years ago that had resolved with pain medication. Her obstetric and gynecological history was unremarkable. She had no history of prior abdominal or pelvic surgery, trauma, abdominal wall or groin hernia, or intestinal inflammation. Furthermore, there was no history of neoplasms, prior abdominopelvic irradiation, or foreign body ingestion. On routine physical examination, she had abdominal distension more pronounced in the lower abdomen, bowel sounds were sluggish, and she had tenderness in left lower abdomen. Digital rectal examination was unremarkable. The rest of the physical examination was unremarkable. Her laboratory tests were unremarkable, including normal lactate levels. A computed tomography (CT) scan of the abdomen revealed acute small bowel obstruction with small bowel predominantly situated in the left lower abdomen, as illustrated in . Conservative management was initiated; however, her abdominal pain and vomiting persisted with increasing tenderness in the lower abdomen. She subsequently underwent a diagnostic laparoscopy, which revealed a congested but viable small bowel herniating through a peritoneal defect in the lateral part of left broad ligament at the lateral pelvic wall into the retroperitoneum. There was congestion of the lateral lower abdominal wall veins. The hernial defect and congested bowel can be seen in and . The small bowel was reduced, it was congested but viable. The defect was closed with titanium surgical clips, after restoring proper bowel alignment. Postoperatively, she had a smooth recovery with no complications and was discharged on the second postoperative day in stable condition. Her follow-up visit with us was unremarkable. 

Literature Review For our literature review, we applied a search strategy on PubMed search using the keywords (“internal pelvic hernia”) and applying the following constraints: publications in humans, English language, free full text, and no time constraints. The search yielded 52 articles, of which the authors excluded 43 due to the lack of relevance to our research focus. The result of this search is demonstrated in . A total of 9 cases were analyzed with an average age of 50.3 years, with the youngest being 28 years old and the oldest being 80 years old. Two of the cases involved male patients and 7 involved female patients. Four of the patients had no history of abdominal surgery, while the other 5 had undergone abdominal surgeries. Of these, 1 only had a radical hysterectomy, while the remaining 4 had variations of pelvic lymph node dissection. – , , For 2 of these patients, their previous surgeries occurred within 1 year of their presentation with an internal pelvic hernia, , whereas the other 3 had undergone their surgeries more than 5 years before presenting with an internal pelvic hernia. , , All patients presented with some variation of the classic symptoms of small bowel obstruction, including abdominal pain, nausea, vomiting, abdominal distention, and constipation. In 6 of the cases, an elevated white blood cell count was noted. Small bowel obstruction was diagnosed in all cases, but only 2 cases identified the internal hernia on CT scan. , One case was initially managed conservatively until the patient deteriorated, prompting the team to perform an exploratory laparotomy, where the internal hernia was identified. In this case, part of the small bowel was nonviable and required resection. In contrast, 6 of the remaining 8 cases were able to reduce the bowel and repair the hernia without necessitating resection. All of the cases had favorable outcomes, with no mortality reported. However, 1 patient experienced several postoperative complications, including thrombosis on day 1 postoperatively, bowel perforation, and bowel necrosis, eventually leading to septic shock 1 week after the operation. The patient also developed a wound infection and transient renal failure but ultimately recovered and was discharged after 66 days. In contrast, none of the other patients had a hospital stay longer than 2 weeks. One of the cases reported in the United States in 2010 has marked similarities with our case. A 35-year-old multiparous woman presented with similar symptoms, and CT scan revealed partial small bowel obstruction. Diagnostic laparotomy found herniated small bowel through a 5-cm defect in the broad ligament, between the round ligament and left adnexa, making it a type 1 broad ligament hernia. This finding is consistent with our patient, who also has a type 1 broad ligament hernial defect. Internal Hernia Internal abdominal hernias vary in incidence. Para-duodenal fossa hernias are the most common (53%), followed by para-cecal fossa hernias (13%), Winslow foramen hernias, and transverse mesenteric fossa hernias (8%). These hernias’ anatomical variations and locations can complicate diagnosis, as symptoms may overlap with other abdominal conditions. , In contrast, internal hernias in the pelvis, including those found in the broad ligament of the uterus, Douglas fossa, and pararectal fossa, occur in less than 6% of cases. Despite their rarity, pelvic internal hernias are noteworthy due to the unique anatomical challenges they present, often requiring a high degree of clinical suspicion for diagnosis. Cases have been documented where internal hernias occurred in the broad ligament of the uterus, emphasizing the need for increased awareness among clinicians regarding this potential complication. Transmesenteric hernias have been observed in 5–10% of cases of internal abdominal hernia and are an important differential to consider. In these cases, diagnostic laparoscopy/laparotomy is warranted. Once the mesenteric defect is identified it should be closed in order to limit the chance of recurrence in the future. Moreover, internal hernias are increasingly observed in patients following bariatric surgery, particularly after laparoscopic gastric bypass procedures, with an estimated incidence of about 5%. The surgical alterations to the gastrointestinal tract and the subsequent weight loss can create new spaces and defects, leading to the potential for herniation. This association highlights the need for vigilant postoperative monitoring and follow-up in patients who have undergone such procedures, as they may present with atypical symptoms or complications related to internal hernias. In our patient, part of the small bowel herniated through a defect in the lateral most part of the broad ligament at the pelvic side wall below the round ligament, making it a type 1 defect according to the Cilley’s classification of broad ligament hernias. According to Hunt’s classification, the fenestra type involves a complete opening in the broad ligament, while the pouch type refers to a pouch within the ligament where bowel may herniate. In our patient, the hernia was of the fenestra type. Etiology Defects of the broad ligament may be either acquired or congenital. Trauma resulting from pregnancy, delivery, pelvic inflammatory disease, or previous surgery represents an acquired cause. Furthermore, in nulliparous patients, such defects may result from spontaneous rupture of cystic structures within the broad ligament that are thought to be congenital remnants of the mesonephric and mullerian ducts. Diagnosis Internal abdominal hernias typically resemble adhesive bowel obstruction, presenting with recurrent small bowel obstructions and postobstructive diarrhea. In the acute setting, they exhibit the classic symptoms of acute small bowel obstruction, including colicky abdominal pain, bilious vomiting, abdominal distension, and constipation. Unlike chronic partial small bowel obstruction, patients are symptom-free after the episode resolves. Imaging plays a pivotal role in the diagnosis of internal hernias. CT is the cornerstone for accurately identifying these complex conditions and crafting active management plans. This is particularly vital, as reliance on nonoperative initial management strategies in mechanical bowel obstruction can lead to delayed intervention and increased morbidity. , , Multidetector CT (MDCT), with its thin-section and high-resolution multiplanar reformatted (MPR) images, is the first-line imaging technique in diagnosing such patients. It is imperative for radiologists to have a detailed understanding of characteristic anatomic location, the clinical findings, and the CT appearance associated with the main types of internal hernia, including para-duodenal, foramen of Winslow, peri-cecal, sigmoid-mesocolon- and transmesenteric-related, transomental, supravesical, and pelvic hernias. Management Equivocal imaging findings and clinical suspicion with no improvement or deterioration necessitate surgical intervention. Abdominal rebound tenderness, advanced leukocytosis (≥18,000/mm³), or a high level of manual band forms (≥6%) have been identified as positive predictive factors for bowel ischemia in cases of internal hernia-related small bowel obstruction. These signs indicate the need for early intervention, such as laparoscopy or laparotomy, to reduce morbidity and mortality in this patient group. The presence of signs of overt sepsis (elevated temperature, high inflammatory markers, tachycardia, low blood pressure, peritonism) indicates the need for active interventional treatment. In the absence of systemic inflammation, a conservative approach through rehydration and aspiration of gastrointestinal contents may be acceptable. However, when sepsis signs are present, urgent surgical intervention is required, potentially involving bowel reduction, resection of ischemic segments, and repair of the hernial defect. There are multiple ways to close the peritoneal defects in internal hernias including sutures, clips, and surgical glues. In this case, as the peritoneal defect was in the lateral lower abdominopelvic wall with redundancy and laxity pronounced at the edges of the defect, using surgical clips was the best option. Suture repair would have been time consuming especially in terms of navigating ergonomics in the context of an emergency laparoscopic exploration. On the other hand, closure by clips spaced 1–1.5 cm apart is efficient, fast and reliable. As narrated by Trindade et al, surgical clips have been used for more than 15 years for peritoneal flap closure for laparoscopic inguinal hernia repairs with mesh with minimal complications. 

For our literature review, we applied a search strategy on PubMed search using the keywords (“internal pelvic hernia”) and applying the following constraints: publications in humans, English language, free full text, and no time constraints. The search yielded 52 articles, of which the authors excluded 43 due to the lack of relevance to our research focus. The result of this search is demonstrated in . A total of 9 cases were analyzed with an average age of 50.3 years, with the youngest being 28 years old and the oldest being 80 years old. Two of the cases involved male patients and 7 involved female patients. Four of the patients had no history of abdominal surgery, while the other 5 had undergone abdominal surgeries. Of these, 1 only had a radical hysterectomy, while the remaining 4 had variations of pelvic lymph node dissection. – , , For 2 of these patients, their previous surgeries occurred within 1 year of their presentation with an internal pelvic hernia, , whereas the other 3 had undergone their surgeries more than 5 years before presenting with an internal pelvic hernia. , , All patients presented with some variation of the classic symptoms of small bowel obstruction, including abdominal pain, nausea, vomiting, abdominal distention, and constipation. In 6 of the cases, an elevated white blood cell count was noted. Small bowel obstruction was diagnosed in all cases, but only 2 cases identified the internal hernia on CT scan. , One case was initially managed conservatively until the patient deteriorated, prompting the team to perform an exploratory laparotomy, where the internal hernia was identified. In this case, part of the small bowel was nonviable and required resection. In contrast, 6 of the remaining 8 cases were able to reduce the bowel and repair the hernia without necessitating resection. All of the cases had favorable outcomes, with no mortality reported. However, 1 patient experienced several postoperative complications, including thrombosis on day 1 postoperatively, bowel perforation, and bowel necrosis, eventually leading to septic shock 1 week after the operation. The patient also developed a wound infection and transient renal failure but ultimately recovered and was discharged after 66 days. In contrast, none of the other patients had a hospital stay longer than 2 weeks. One of the cases reported in the United States in 2010 has marked similarities with our case. A 35-year-old multiparous woman presented with similar symptoms, and CT scan revealed partial small bowel obstruction. Diagnostic laparotomy found herniated small bowel through a 5-cm defect in the broad ligament, between the round ligament and left adnexa, making it a type 1 broad ligament hernia. This finding is consistent with our patient, who also has a type 1 broad ligament hernial defect. 

Internal abdominal hernias vary in incidence. Para-duodenal fossa hernias are the most common (53%), followed by para-cecal fossa hernias (13%), Winslow foramen hernias, and transverse mesenteric fossa hernias (8%). These hernias’ anatomical variations and locations can complicate diagnosis, as symptoms may overlap with other abdominal conditions. , In contrast, internal hernias in the pelvis, including those found in the broad ligament of the uterus, Douglas fossa, and pararectal fossa, occur in less than 6% of cases. Despite their rarity, pelvic internal hernias are noteworthy due to the unique anatomical challenges they present, often requiring a high degree of clinical suspicion for diagnosis. Cases have been documented where internal hernias occurred in the broad ligament of the uterus, emphasizing the need for increased awareness among clinicians regarding this potential complication. Transmesenteric hernias have been observed in 5–10% of cases of internal abdominal hernia and are an important differential to consider. In these cases, diagnostic laparoscopy/laparotomy is warranted. Once the mesenteric defect is identified it should be closed in order to limit the chance of recurrence in the future. Moreover, internal hernias are increasingly observed in patients following bariatric surgery, particularly after laparoscopic gastric bypass procedures, with an estimated incidence of about 5%. The surgical alterations to the gastrointestinal tract and the subsequent weight loss can create new spaces and defects, leading to the potential for herniation. This association highlights the need for vigilant postoperative monitoring and follow-up in patients who have undergone such procedures, as they may present with atypical symptoms or complications related to internal hernias. In our patient, part of the small bowel herniated through a defect in the lateral most part of the broad ligament at the pelvic side wall below the round ligament, making it a type 1 defect according to the Cilley’s classification of broad ligament hernias. According to Hunt’s classification, the fenestra type involves a complete opening in the broad ligament, while the pouch type refers to a pouch within the ligament where bowel may herniate. In our patient, the hernia was of the fenestra type. 

Defects of the broad ligament may be either acquired or congenital. Trauma resulting from pregnancy, delivery, pelvic inflammatory disease, or previous surgery represents an acquired cause. Furthermore, in nulliparous patients, such defects may result from spontaneous rupture of cystic structures within the broad ligament that are thought to be congenital remnants of the mesonephric and mullerian ducts. 

Internal abdominal hernias typically resemble adhesive bowel obstruction, presenting with recurrent small bowel obstructions and postobstructive diarrhea. In the acute setting, they exhibit the classic symptoms of acute small bowel obstruction, including colicky abdominal pain, bilious vomiting, abdominal distension, and constipation. Unlike chronic partial small bowel obstruction, patients are symptom-free after the episode resolves. Imaging plays a pivotal role in the diagnosis of internal hernias. CT is the cornerstone for accurately identifying these complex conditions and crafting active management plans. This is particularly vital, as reliance on nonoperative initial management strategies in mechanical bowel obstruction can lead to delayed intervention and increased morbidity. , , Multidetector CT (MDCT), with its thin-section and high-resolution multiplanar reformatted (MPR) images, is the first-line imaging technique in diagnosing such patients. It is imperative for radiologists to have a detailed understanding of characteristic anatomic location, the clinical findings, and the CT appearance associated with the main types of internal hernia, including para-duodenal, foramen of Winslow, peri-cecal, sigmoid-mesocolon- and transmesenteric-related, transomental, supravesical, and pelvic hernias. 

Equivocal imaging findings and clinical suspicion with no improvement or deterioration necessitate surgical intervention. Abdominal rebound tenderness, advanced leukocytosis (≥18,000/mm³), or a high level of manual band forms (≥6%) have been identified as positive predictive factors for bowel ischemia in cases of internal hernia-related small bowel obstruction. These signs indicate the need for early intervention, such as laparoscopy or laparotomy, to reduce morbidity and mortality in this patient group. The presence of signs of overt sepsis (elevated temperature, high inflammatory markers, tachycardia, low blood pressure, peritonism) indicates the need for active interventional treatment. In the absence of systemic inflammation, a conservative approach through rehydration and aspiration of gastrointestinal contents may be acceptable. However, when sepsis signs are present, urgent surgical intervention is required, potentially involving bowel reduction, resection of ischemic segments, and repair of the hernial defect. There are multiple ways to close the peritoneal defects in internal hernias including sutures, clips, and surgical glues. In this case, as the peritoneal defect was in the lateral lower abdominopelvic wall with redundancy and laxity pronounced at the edges of the defect, using surgical clips was the best option. Suture repair would have been time consuming especially in terms of navigating ergonomics in the context of an emergency laparoscopic exploration. On the other hand, closure by clips spaced 1–1.5 cm apart is efficient, fast and reliable. As narrated by Trindade et al, surgical clips have been used for more than 15 years for peritoneal flap closure for laparoscopic inguinal hernia repairs with mesh with minimal complications. 

Internal abdominal hernias are crucial differential diagnoses of acute abdominal pain and small bowel obstruction. Delay in diagnosis and hence management may result in significant morbidity and high mortality. It should be included in the routine differential diagnosis when assessing adult patients with chronic vague gastrointestinal symptoms, intermittent small bowel obstructions with postobstructive diarrhea, and especially in cases of acute abdomen for surgeons, emergency physicians, and gastroenterologists. High vigilance, thorough awareness, and appropriate treatment strategies are vital to reduce the morbidity and mortality associated with internal abdominopelvic hernias. 

