Internal Hernia Through the Pars Flaccida: A Rare Intraoperative Finding.

A 52-year-old woman presented with recurrent episodes of epigastric abdominal pain. Her past medical history was significant for gastroesophageal reflux disease, endometriosis, total thyroidectomy for papillary thyroid carcinoma, and rectosigmoid-invasive moderately differentiated adenocarcinoma (Stage IIIA – pT2N1aM0) diagnosed in 2017. She underwent laparoscopic low anterior resection with a colonic J-pouch creation followed by FOLFOX adjuvant chemotherapy. Starting December 2018, she developed intermittent bouts of diffuse abdominal pain, initially attributed to inflammatory bowel syndrome. These episodes continued through 2019 and increased in frequency by 2021. The patient described a consistent pain pattern that began in the right side of her abdomen, progressed to the umbilical region, and extended up to the sternum. During a severe episode in 2021, she went to the emergency department and a CT of the abdomen and pelvis revealed a left-sided colon volvulus requiring decompression via flexible scope. Subsequently, she underwent robot-assisted left colectomy with colonic J-pouch resection, splenic flexure mobilization, coloanal anastomosis, and diverting loop ileostomy in 2021, with stoma reversal in 2022. After stoma reversal, she continued to experience multiple episodes of epigastric abdominal pain and nausea. These episodes typically lasted approximately 1 hour and were characterized by severe nausea without vomiting. In September 2024, emergency department evaluation, including CT imaging, suggested malrotation of the small bowel with small bowel located in the left of the abdomen and large bowel in the right, as well as swirling of the small bowel, suggesting a volvulus, but no evidence of obstruction or bowel thickening. The patient presented to our clinic in October 2024 with a long history of epigastric pain, nausea, and non-bloody, non-bilious emesis. Repeat CT imaging demonstrated abnormal positioning of small-bowel loops, with evidence of swirling, consistent with an internal hernia. Given her complex surgical history and recurrent symptoms, she was scheduled for diagnostic laparoscopy to investigate for internal hernia versus intermittent volvulus.

Internal hernias are an uncommon but clinically important cause of small-bowel obstruction, with an overall incidence of less than 1%, and accounting for approximately 0.6% to 5.8% of all intestinal obstruction cases [ 1 , 2 ]. These hernias are defined by the protrusion of viscera through normal or abnormal peritoneal or mesenteric apertures while remaining within the peritoneal cavity [ 3 , 4 ]. While traditionally classified into several anatomical subtypes, herniation through the pars flaccida of the lesser omentum is an extremely rare variant that poses unique diagnostic and therapeutic challenges [ 5 ]. The pars flaccida, forming part of the hepatogastric ligament, is an anatomically complex region where iatrogenic defects can develop after upper-abdominal surgery [ 6 ]. Unlike more common internal hernias such as paraduodenal (53%), pericecal (13%), or transmesenteric (8%) variants, pars flaccida hernias have been only sporadically reported in the literature [ 1 , 7 ]. The rarity of this condition, combined with its nonspecific clinical presentation, makes preoperative diagnosis particularly challenging [ 8 ]. Recent studies have demonstrated an increasing incidence of internal hernias, largely attributed to the growing adoption of laparoscopic surgical procedures [ 9 , 10 ]. While much attention has focused on internal hernias following bariatric surgery, particularly Roux-en-Y gastric bypass, pars flaccida herniation presents distinct anatomical and technical considerations that warrant specific attention [ 11 ]. Diagnosis often remains challenging due to variable symptoms, ranging from intermittent mild digestive problems to acute intestinal obstruction [ 12 ]. While computed tomography (CT) has emerged as the primary diagnostic tool, the radiological features of pars flaccida hernias can be subtle and may not demonstrate the classical signs associated with other internal hernias, such as the “swirl sign” [ 13 ]. We present a case of successful laparoscopic management of an internal hernia through the pars flaccida, highlighting the diagnostic approach, operative technique, and specific considerations for minimally invasive repair. This report aims to contribute to the limited literature on this rare entity and provide practical insights for surgeons encountering similar cases.

Internal hernias through the pars flaccida are exceedingly rare, with limited literature guiding their surgical management. We present our technical approach and key considerations for successful laparoscopic repair based on this case. Importantly, while internal hernias are traditionally viewed as acute emergencies requiring immediate surgical intervention, our experience and the literature review suggest that patients can present with months or years of chronic symptoms before diagnosis. This necessitates a higher index of suspicion in post-surgical patients presenting with chronic, often postprandial, abdominal pain or bloating, rather than limiting consideration to those with acute obstruction. Preoperative planning is crucial for successful management of these complex cases. A thorough review of the surgical history is essential, particularly in patients with multiple abdominal operations. Careful analysis of CT imaging should focus on identifying abnormal small bowel position relative to the stomach, mesenteric vessel orientation, evidence of bowel obstruction, and anatomical distortion from previous surgeries. Our surgical approach began with careful abdominal access. Initial entry was achieved via Palmer’s point using Veress needle technique. A strategic 5-port approach was employed, with a 10-mm infraumbilical camera port (initially placed as 5 mm and then upsized) and four 5-mm working ports placed in each quadrant. This port configuration provided optimal working space in the upper abdomen. The procedure started with a systematic exploration of the abdomen. After initial diagnostic laparoscopy, methodical adhesiolysis was performed using a combination of blunt and electrocautery dissection. On laparoscopic entry, most of the small bowel was herniated through the pars flaccida, as demonstrated in the video. A key finding was the unexpected position of the small bowel anterior to the mid-portion of the stomach. Specific anatomical structures identified included the stomach, pars flaccida (the defect site within the lesser omentum was clearly delineated), small bowel, remaining colon, and small bowel mesentery. This systematic identification of anatomical landmarks was crucial for guiding our dissection and ensuring complete reduction of the hernia. The hernia reduction and repair phase required meticulous attention to detail. We carefully traced the small bowel course to identify the hernia entry point through the pars flaccida. The herniated bowel was gently reduced, reestablishing normal anatomy. The defect was then closed using a running 2-0 Ethibond suture. A thorough assessment for additional defects was performed by running the entire small bowel, which revealed a secondary mesenteric defect between the small bowel and transverse mesocolon. This was closed using interrupted 2-0 Ethibond sutures. The procedure was completed with a thorough final inspection ensuring appropriate bowel orientation. All ports were removed under direct visualization, with the 10-mm infraumbilical fascial defect closed using a figure-of-eight 0 Ethibond suture. Skin closure was performed with buried 4-0 Monocryl sutures. See Video 1 . Use of Palmer’s point for initial access provides safe entry in patients with multiple previous surgeries. Strategic port placement is crucial for optimal visualization and instrument triangulation. Systematic bowel examination in both directions helps identify additional defects. Non-absorbable suture material (Ethibond) is preferred for defect closure. Importance of checking for additional mesenteric defects that may have developed from previous surgeries. Risk of bowel injury during adhesiolysis. Challenge of identifying normal anatomical landmarks in post-surgical patients. Importance of gentle tissue handling during bowel reduction. Need for thorough inspection to identify additional defects. This systematic approach allows for safe and effective management of pars flaccida hernias while minimizing the risk of complications. The key to success lies in meticulous attention to anatomical details, careful tissue handling, and thorough inspection for additional defects. A comprehensive literature review was conducted using the PubMed database to identify previously reported cases of internal hernias through the pars flaccida of the lesser omentum (also known as gastrohepatic or hepatogastric ligament) managed laparoscopically. The search strategy included combinations of the terms “internal hernia”, “pars flaccida”, “lesser omentum”, “gastrohepatic ligament”, and “hepatogastric ligament”. Table 1 summarizes the published cases identified through this search. When comparing our case to the existing literature on pars flaccida hernias, several important distinctions emerge. Unlike the cases reported by Masubuchi et al [ 14 ] and Makutani et al [ 15 ], which occurred following colectomy procedures, our patient had undergone multiple colorectal surgeries, including low anterior resection, volvulus treatment, and subsequent coloanal anastomosis, creating a more complex surgical background. The technical approach described by Ugianskis [ 3 ] involved a 35-year-old man with BMI 21 following total colectomy, where the entire small intestine, including the duodenojejunal flexure, was herniated through the lesser omentum, requiring creation of a neo-lesser sac rather than primary closure due to the large defect size. In contrast, our case allowed for primary defect closure using non-absorbable sutures, similar to the approach described by Alves et al [ 16 ]. The presentation timeline also differed significantly – while Makutani et al [ 15 ] reported cases occurring 4 to 6 months after colectomy, and Masubuchi et al [ 14 ] described herniation 42 months after surgery, our patient developed symptoms years after her initial colorectal cancer surgery, with multiple intervening procedures. The laparoscopic approach we employed aligns with the minimally invasive techniques described across all published cases, though our identification of a secondary mesenteric defect requiring separate repair was unique among the reported literature and highlights the importance of comprehensive bowel examination in patients with complex surgical histories. Our patient’s regular postoperative follow-up exam showed complete symptom resolution. At 8 months after laparoscopic repair, she underwent a CT scan, which found no acute abnormalities and demonstrated appropriate bowel positioning without evidence of hernia recurrence. She has remained asymptomatic throughout the follow-up period. While our current follow-up period of 8 months demonstrates early success of the laparoscopic approach, we acknowledge that longer-term follow-up data would further strengthen the evidence for durability of this repair technique. Given the rarity of pars flaccida hernias, accumulating long-term outcome data will be important for establishing the optimal management approach for this uncommon condition.

Internal hernias through the pars flaccida are a rare but clinically significant surgical condition that requires a high index of suspicion for diagnosis. Our case demonstrates that successful laparoscopic management is feasible with careful attention to anatomical details and systematic surgical technique. The key to successful repair lies in preoperative planning, strategic port placement, and thorough inspection for additional defects. This case highlights the importance of considering internal hernias in the differential diagnosis for patients with intermittent abdominal pain following previous surgery, even when initial imaging studies are inconclusive. Given the increasing number of laparoscopic procedures being performed, surgeons should maintain awareness of this potential complication and be familiar with the technical aspects of its repair.