J Gastrointest Surg DOI 10.1007/s11605-014-2527-z
CASE REPORT
Small Bowel Obstruction Caused by an Unusual Variant of Paraduodenal Hernia. The “Middle Congenital Mesocolic Hernia”: Case Report Alessio Licciardello & Cristian Rapisarda & Pietro Conti & Giovanni Trombatore
Received: 26 February 2014 / Accepted: 7 April 2014 # 2014 The Society for Surgery of the Alimentary Tract
Abstract Internal hernias account for 0.2–0.9 % of all small bowel obstructions and are associated with a mortality rate of 50 % when strangulation is present. Congenital mesocolic hernias, traditionally called paraduodenal hernias, caused by an abnormal rotation of the primitive midgut, are the most common type of internal hernia. They can be divided into three types: the right and the left congenital mesocolic hernias, accounting for the 25 and 75 % of all cases, respectively, and the extremely rare transverse congenital mesocolic hernia. A high preoperative misdiagnosis rate has been reported and a surgical exploration is recommended to identify strangulation. The present case report describes a case of small bowel obstruction due to an unusual variant of congenital mesocolic hernia never previously reported in the literature. We discuss the clinical appearance, pathogenesis, diagnosis, and treatment of the case, with a brief review of the literature focused on the pathogenesis and management of mesocolic congenital hernias. Keywords Paraduodenal hernia . Congenital mesocolic hernia . Internal hernia
Herein, we report a case of small bowel obstruction due to an unusual variant of congenital mesocolic hernia not previously described in the literature.
Introduction Internal hernias, accounting for about 0.2–0.9 % of all hernias,1 are uncommon small bowel obstructions, which, if left untreated, have a reported overall mortality rate of 50 % when stran, gulation is present.2 3 Because of their rarity, they are often misdiagnosed, with subsequent significant morbidity and mortality.4 Internal hernias are classified based on location, and the hernial orifice can be either congenital or acquired. Paraduodenal hernias are the most common type associated with small bowel obstruction. They are caused by the invagination of the small bowel into an avascular and unsupported segment of the mesocolon during the primitive midgut rotation. They are also called mesentericoparietal, Treit’s, and retroperitoneal hernias, but they should be more appropriately called , congenital mesocolic hernias based on their pathogenesis.3 5 A. Licciardello : C. Rapisarda : P. Conti : G. Trombatore Division of General Surgery, Civil Hospital of Lentini, C/da Colle Roggio, 96016 Lentini, SR, Italy A. Licciardello (*) Viale Regina Margherita 38, 95024 Acireale, CT, Italy e-mail: [email protected]
Case Report A 45-year-old male patient was admitted to our emergency department with pain in the upper abdomen, vomiting, and complete constipation. He reported that pain started 10 days before admission and had increased over the last 2 days. The patient also reported mild cramping pain after meals for the last 2 years. He had no previous abdominal surgery history. Abdominal examination revealed abdominal distention and increased peristaltic activity. Laboratory test showed a leucocytosis (white blood cell [WBC] 13,100/mL). Abdominal ultrasound (US) revealed distended small bowel loops and perisplenic fluid. Upright abdominal x-ray showed distended small bowel loops that occupied the left upper quadrant. A diagnosis of bowel obstruction was made and the patient was initially medically treated. Next, the patient underwent a computed tomography (CT) scan of abdomen with intravenous contrast. This study revealed a “cluster” of distended bowel loops in the upper abdominal cavity, with inferior displacement of the transverse colon (Fig. 1). The mesenteric vessels were twisted, engorged, and stretched. The superior
J Gastrointest Surg
mesenteric artery (SMA) and vein were stretched to the left by the mesenteric vessels. The middle colic artery (MCA) was displaced to the right and elongated to the transverse colon (Fig. 1). With these findings, which were highly suspicious of an internal hernia, the patient was taken to the operative room for an explorative laparotomy. The transverse colon was not in
its usual position, but was located in the lower quadrant. The gastrocolic ligament was elongated and stretched. Only the last four small bowel loops emerged from the base of the transverse mesocolon. Sectioning of the gastrocolic ligament revealed almost all small bowel loops encapsulated between the body of the pancreas and third duodenum and an avascular sac of peritoneum that originated from the posterior wall of the abdomen and, inferiorly, from the anterior and the lateral rims of a tight orifice of the transverse mesocolon (Fig. 2). The sac left the posterior abdominal wall at the duodenal-jejunal junction superiorly and along the MCA, to the right, and the inferior mesenteric vein (IMV), to the left, laterally. After opening the sac, the bowel loops appeared dilated and thickened. Further exploration revealed that the root of mesentery was in the normal anatomical position, while the transverse mesocolon was fixed at the level of the bisiliac line, crossing anteriorly the fourth last bowel loop, leading to the creation of a tight orifice between the transverse colon and the posterior wall (Fig. 2). The right rim of the orifice was edged by the last tract of the MCA. Attempts to reduce the loops through the hernial orifice were not successful because most of the root of the mesentery was located above the root of the transverse mesocolon. We considered it dangerous to reposition the colon to its normal anatomical position because of the risk of
Fig. 2 Schematic drawings of congenital mesocolic hernias. a Middle congenital mesocolic hernia. b Sagittal section of middle congenital mesocolic hernia. c Middle mesocolic congenital hernia after sectioning of the hernia sac. d Right congenital mesocolic hernia. The small bowel is herniated into the mesenterical-parietal fossa of Waldeyer, laterally and inferiorly to the third portion of the duodenum, behind the right mesocolon. The SMA and one of its branches run to the lower part of
the sac along the anterior margin of mesenteric defect. e Left congenital mesocolic hernia. The small bowel is invaginated in the fossa of Landzert, behind the left mesocolon, laterally to the fourth portion of the duodenum and posteriorly to the inferior mesenteric vein (IMV) that runs in the left mesocolon. f Transverse congenital mesocolic hernia. The transverse colon is invaginated behind the SMA and the mesentery. The duodenum is anterior to the SMA
Fig. 1 Computed tomography contrast scan. a Cluster of small bowel loops in the upper abdomen between the stomach and pancreas. The transverse colon is displaced inferiorly. The loops appear distended and thickened. b Maximum intensity projection (MIP) reconstruction. The superior mesenteric artery (SMA) and vein appear in their normal retroperitoneal position, but are stretched to the left by the mesenteric vessels. The mesenteric vessels are engorged and stretched. The middle colic artery (MCA), originated from the SMA, is displaced to the right and elongated. The last bowel loops appear empty
J Gastrointest Surg
Congenital mesocolic (paraduodenal) hernias are the most common type of internal hernias, accounting for 30–53 % of
all cases. Although they are congenital, most patients are recognized between the fourth and the sixth decades of life.1 They are more frequently reported in male patients with a sex ratio of 3:1. While some patients are asymptomatic, a history of chronic nonspecific symptoms (median duration of 1.8 years) preceding an episode of bowel obstruction or strangulation is reported to occur in 69 % of cases.3 Chronic symptoms include dyspepsia, intermittent colicky abdominal pain, and vomiting.6 Congenital mesocolic hernias can be divided into three types: the right and the left congenital mesocolic hernias, accounting for 25 and 75 % of all cases, respectively,1 and the extremely rare, transverse mesocolic hernia (Fig. 2).5 As previously mentioned, they result from an abnormal rotation of the primitive gut. Between the fifth and the twelfth week of normal gestation of the human embryo, the primitive midgut undergoes a counterclockwise rotation of 270° around the SMA (Fig. 4). Usually, fusion of the duodenum, mesentery, and mesocolon with the peritoneum of the posterior wall follows this process.7 Right congenital mesocolic hernia occurs when the pre-arterial limb terminates its counterclockwise rotation at 180° and the post-arterial segment continues to develop and rotate normally. Thus, all or part of small bowel becomes trapped behind and on the right side of the SMA and behind the right mesocolon that fails to fuse with the peritoneum of the posterior wall resulting in a sac.8 The
Fig. 4 Between the fifth and tenth week of normal gestation of the human embryo, the primitive midgut is herniated outside the abdomen into the umbilical cord (a). During this period, the herniated midgut undergoes a counterclockwise rotation of 90° around the SMA, leaving the pre-arterial limb on the right side and the post-arterial on the left (b). During the tenth week of gestation, the midgut quickly returns into the abdominal cavity, while at the same time undergoing a counterclockwise rotation of 90°(c). The last stage of rotation occurs between the tenth and
twelfth week, with a further counterclockwise rotation of 90° (d). In the end, the pre-arterial limb lies to the left of the SMA and the post-arterial limb lies superior and to the right of the SMA (e). Middle congenital mesocolic hernia: between the tenth and twelfth week, the post-arterial limb terminates its rotation prior to 270° (f). Thus, at the twelfth week of gestation, the post-arterial limb remains in a lower position, crossing the SMA anteriorly, and most of the pre-arterial limb is localized behind the transverse mesocolon (g)
Fig. 3 Surgical procedure performed
vascular injuries. Therefore, to remove the obstruction, we resected the incarcerated loop. Intestinal continuity was restored by an ileo-ileal antecolic hand-sewn anastomosis (Fig. 3). Postoperative recovery was uneventful and the patient was discharged 6 days after surgery. No early postoperative or late complications occurred. The patient had complete symptoms resolution at 3, 6, and 12-month reviews.
Discussion
J Gastrointest Surg
pathogenesis of left congenital mesocolic hernias is more , , , controversial. Most authors believe that it is caused,3 5 7 8 during the midgut rotation, by invagination of the small bowel between the posterior wall and a segment of the left mesocolon that therefore fails to fuse and forms the anterior wall of the hernia sac. However, some authors have suggested that primitive fusion failure of the left mesocolon results in a , congenital fossa,1 9 where the small bowel herniates later on. The rare transverse congenital mesocolic hernia results when there is a reversed rotation of the midgut and subsequent invagination of the transverse mesocolon and a portion of the right side of the colon.5 The case reported here is a unique case of congenital mesocolic hernia that has never been previously reported. We hypothesize that, in our patient, during the last stage of the rotation, the pre-arterial limb completed its development and rotated normally, while the post-arterial limb terminated its counterclockwise rotation prior to 270°. Therefore, the post-arterial-limb remained in a lower position, not located superiorly to the SMA, but crossing the SMA anteriorly. Thus, at the twelfth week of gestation, the pre-arterial limb is localized behind the transverse mesocolon, between the MCA and the IMV (Fig. 4). As a result, the portion of the transverse mesocolon between the MCA and IMV, inferiorly to the duodenal-jejunal junction, and anteriorly to the pancreas and the third portion of duodenum, failed to fuse, resulting in a fossa. As the pre-arterial limb continued to elongate, almost all of the small bowel loops became trapped in a sac behind the transverse mesocolon. We believe that this type of internal hernia should be called middle congenital mesocolic hernia based on its pathogenesis. The uncommon presence of internal hernias and the absence of specific clinical features make a clinical diagnosis of congenital mesocolic hernia difficult. CT scan has become the first-line imaging technique in these patients.5 CT scans can demonstrate the encapsulated cluster of small bowel loops within the hernia sac with abnormal location, evidence of obstruction with segmental dilatation or stasis, and displace, , , ment of right, left, or transverse colon.3 4 10 11 In this type of hernia, the mesenteric vessels are commonly engorged, crowded, twisted, and stretched. Additional vascular findings include displacement of the SMA and its branch or displace, ment of the IMV, according to the type of hernia.4 11 In our case, the CT scan was important to arouse suspicion of the presence of an internal hernia and, therefore, to provide an early indication for surgery. The treatment of choice for congenital mesocolic hernias is surgery, which is recommended for all patients fit to undergo laparotomy, due to the high lifetime probability of strangulation and incarceration (50 %).11 In the last few years, laparoscopic treatment has also been reported as a feasible and safe surgical option for the treatment of congenital mesocolic , hernias in selected patients.10 12 The basic management
principles, as for all hernias, are reduction of hernia content , and repair of the defect.3 11 During operation, repositioning of the bowel loops should be performed respecting their correct anatomical location as much as possible and vascular injuries must be carefully avoided as to not compromise the bloody supply of the small and large bowels. However, in our case, given the anatomical anomalies we discovered, it was deemed dangerous to reposition the small and large bowels to their normal anatomical position. In conclusion, congenital mesocolic (paraduodenal) hernias are a rare cause of small bowel obstruction. Herein, we present an unreported type of congenital mesocolic (paraduodenal) hernia: the middle congenital mesocolic hernia. The remote possibility of a congenital mesocolic hernia should be kept in mind by clinicians treating small bowel obstructions in patients with a history of chronic dyspepsia, intermittent colicky abdominal pain, and vomiting, without previous laparotomy. Although the clinical diagnosis is difficult, CT findings can be very useful for arousing suspicion preoperatively. Surgical treatment is always recommended.
References 1. Khan MA, Lo YA, Vande Maele DM. Paraduodenal hernia. Am Surg 1998; 64:1218–1222. 2. Newsom BD, Kukora JS. Congenital and acquired internal hernias: unusual causes of small bowel occlusion. Am J Surg 1986; 152:279–284. 3. Tong RSK, Sengupta S, Tjandra JJ. Left paraduodenal hernia: case report and review of the literature. ANZ J Surg 2002; 72:69–71. 4. Martin LC, Merkle EM, Thomson EM. Review of internal hernias: radiological and clinical findings. AJR 2006; 186:703–717. 5. Willwerth BM, Zollinger RM, Izant RJ. Congenital mesocolic (paraduodenal) hernia. Embryologic basis of repair. Am J Surg 1974; 128:358–361. 6. Frediani S, Almberger M, Iaconelli R, Avventurieri G, Manganaro F. An unusual case of congenital mesocolic hernia. Hernia 2010; 14: 105–107. 7. Berardi RS. Paraduodenal hernias. Surg Gynecol Obstet 1981; 152: 99–110. 8. Moran JM, Salas J, Sanjuán S, Amaya JL, Rincón P, Serrano A, Tallo EM. Paramesocolic hernias: consequences of delayed diagnosis. Report of three new cases. J Pediatr Surg 2004; 39: 112–116. 9. Brigham RA, Fallon WF, Saunders JR, Harmon JW, d’Avis JC. Paraduodenal hernia: diagnosis and surgical management. Surgery 1984; 96:498–502. 10. Bittner JG 4th, Edwards MA, Harrison SJ, Li K, Karmin PN, Mellinger JD. Laparoscopic repair of right paraduodenal hernia. JSLS 2009; 13:242–249. 11. Zonca P, Maly T, Mole DJ, Stigler J. Treitz’s hernia. Hernia 2008; 12: 531–534. 12. Hussein M, Khreiss M, Al-Helou G, Aleaddine M, Elias E, Abi Saad GS. Laparoscopic repair of a left paraduodenal hernia presenting with acute bowel obstruction: report of a case. Surg Laparosc Endosc Percutan Tech 2012; 22:e28-30.
CASE REPORT
Small Bowel Obstruction Caused by an Unusual Variant of Paraduodenal Hernia. The “Middle Congenital Mesocolic Hernia”: Case Report Alessio Licciardello & Cristian Rapisarda & Pietro Conti & Giovanni Trombatore
Received: 26 February 2014 / Accepted: 7 April 2014 # 2014 The Society for Surgery of the Alimentary Tract
Abstract Internal hernias account for 0.2–0.9 % of all small bowel obstructions and are associated with a mortality rate of 50 % when strangulation is present. Congenital mesocolic hernias, traditionally called paraduodenal hernias, caused by an abnormal rotation of the primitive midgut, are the most common type of internal hernia. They can be divided into three types: the right and the left congenital mesocolic hernias, accounting for the 25 and 75 % of all cases, respectively, and the extremely rare transverse congenital mesocolic hernia. A high preoperative misdiagnosis rate has been reported and a surgical exploration is recommended to identify strangulation. The present case report describes a case of small bowel obstruction due to an unusual variant of congenital mesocolic hernia never previously reported in the literature. We discuss the clinical appearance, pathogenesis, diagnosis, and treatment of the case, with a brief review of the literature focused on the pathogenesis and management of mesocolic congenital hernias. Keywords Paraduodenal hernia . Congenital mesocolic hernia . Internal hernia
Herein, we report a case of small bowel obstruction due to an unusual variant of congenital mesocolic hernia not previously described in the literature.
Introduction Internal hernias, accounting for about 0.2–0.9 % of all hernias,1 are uncommon small bowel obstructions, which, if left untreated, have a reported overall mortality rate of 50 % when stran, gulation is present.2 3 Because of their rarity, they are often misdiagnosed, with subsequent significant morbidity and mortality.4 Internal hernias are classified based on location, and the hernial orifice can be either congenital or acquired. Paraduodenal hernias are the most common type associated with small bowel obstruction. They are caused by the invagination of the small bowel into an avascular and unsupported segment of the mesocolon during the primitive midgut rotation. They are also called mesentericoparietal, Treit’s, and retroperitoneal hernias, but they should be more appropriately called , congenital mesocolic hernias based on their pathogenesis.3 5 A. Licciardello : C. Rapisarda : P. Conti : G. Trombatore Division of General Surgery, Civil Hospital of Lentini, C/da Colle Roggio, 96016 Lentini, SR, Italy A. Licciardello (*) Viale Regina Margherita 38, 95024 Acireale, CT, Italy e-mail: [email protected]
Case Report A 45-year-old male patient was admitted to our emergency department with pain in the upper abdomen, vomiting, and complete constipation. He reported that pain started 10 days before admission and had increased over the last 2 days. The patient also reported mild cramping pain after meals for the last 2 years. He had no previous abdominal surgery history. Abdominal examination revealed abdominal distention and increased peristaltic activity. Laboratory test showed a leucocytosis (white blood cell [WBC] 13,100/mL). Abdominal ultrasound (US) revealed distended small bowel loops and perisplenic fluid. Upright abdominal x-ray showed distended small bowel loops that occupied the left upper quadrant. A diagnosis of bowel obstruction was made and the patient was initially medically treated. Next, the patient underwent a computed tomography (CT) scan of abdomen with intravenous contrast. This study revealed a “cluster” of distended bowel loops in the upper abdominal cavity, with inferior displacement of the transverse colon (Fig. 1). The mesenteric vessels were twisted, engorged, and stretched. The superior
J Gastrointest Surg
mesenteric artery (SMA) and vein were stretched to the left by the mesenteric vessels. The middle colic artery (MCA) was displaced to the right and elongated to the transverse colon (Fig. 1). With these findings, which were highly suspicious of an internal hernia, the patient was taken to the operative room for an explorative laparotomy. The transverse colon was not in
its usual position, but was located in the lower quadrant. The gastrocolic ligament was elongated and stretched. Only the last four small bowel loops emerged from the base of the transverse mesocolon. Sectioning of the gastrocolic ligament revealed almost all small bowel loops encapsulated between the body of the pancreas and third duodenum and an avascular sac of peritoneum that originated from the posterior wall of the abdomen and, inferiorly, from the anterior and the lateral rims of a tight orifice of the transverse mesocolon (Fig. 2). The sac left the posterior abdominal wall at the duodenal-jejunal junction superiorly and along the MCA, to the right, and the inferior mesenteric vein (IMV), to the left, laterally. After opening the sac, the bowel loops appeared dilated and thickened. Further exploration revealed that the root of mesentery was in the normal anatomical position, while the transverse mesocolon was fixed at the level of the bisiliac line, crossing anteriorly the fourth last bowel loop, leading to the creation of a tight orifice between the transverse colon and the posterior wall (Fig. 2). The right rim of the orifice was edged by the last tract of the MCA. Attempts to reduce the loops through the hernial orifice were not successful because most of the root of the mesentery was located above the root of the transverse mesocolon. We considered it dangerous to reposition the colon to its normal anatomical position because of the risk of
Fig. 2 Schematic drawings of congenital mesocolic hernias. a Middle congenital mesocolic hernia. b Sagittal section of middle congenital mesocolic hernia. c Middle mesocolic congenital hernia after sectioning of the hernia sac. d Right congenital mesocolic hernia. The small bowel is herniated into the mesenterical-parietal fossa of Waldeyer, laterally and inferiorly to the third portion of the duodenum, behind the right mesocolon. The SMA and one of its branches run to the lower part of
the sac along the anterior margin of mesenteric defect. e Left congenital mesocolic hernia. The small bowel is invaginated in the fossa of Landzert, behind the left mesocolon, laterally to the fourth portion of the duodenum and posteriorly to the inferior mesenteric vein (IMV) that runs in the left mesocolon. f Transverse congenital mesocolic hernia. The transverse colon is invaginated behind the SMA and the mesentery. The duodenum is anterior to the SMA
Fig. 1 Computed tomography contrast scan. a Cluster of small bowel loops in the upper abdomen between the stomach and pancreas. The transverse colon is displaced inferiorly. The loops appear distended and thickened. b Maximum intensity projection (MIP) reconstruction. The superior mesenteric artery (SMA) and vein appear in their normal retroperitoneal position, but are stretched to the left by the mesenteric vessels. The mesenteric vessels are engorged and stretched. The middle colic artery (MCA), originated from the SMA, is displaced to the right and elongated. The last bowel loops appear empty
J Gastrointest Surg
Congenital mesocolic (paraduodenal) hernias are the most common type of internal hernias, accounting for 30–53 % of
all cases. Although they are congenital, most patients are recognized between the fourth and the sixth decades of life.1 They are more frequently reported in male patients with a sex ratio of 3:1. While some patients are asymptomatic, a history of chronic nonspecific symptoms (median duration of 1.8 years) preceding an episode of bowel obstruction or strangulation is reported to occur in 69 % of cases.3 Chronic symptoms include dyspepsia, intermittent colicky abdominal pain, and vomiting.6 Congenital mesocolic hernias can be divided into three types: the right and the left congenital mesocolic hernias, accounting for 25 and 75 % of all cases, respectively,1 and the extremely rare, transverse mesocolic hernia (Fig. 2).5 As previously mentioned, they result from an abnormal rotation of the primitive gut. Between the fifth and the twelfth week of normal gestation of the human embryo, the primitive midgut undergoes a counterclockwise rotation of 270° around the SMA (Fig. 4). Usually, fusion of the duodenum, mesentery, and mesocolon with the peritoneum of the posterior wall follows this process.7 Right congenital mesocolic hernia occurs when the pre-arterial limb terminates its counterclockwise rotation at 180° and the post-arterial segment continues to develop and rotate normally. Thus, all or part of small bowel becomes trapped behind and on the right side of the SMA and behind the right mesocolon that fails to fuse with the peritoneum of the posterior wall resulting in a sac.8 The
Fig. 4 Between the fifth and tenth week of normal gestation of the human embryo, the primitive midgut is herniated outside the abdomen into the umbilical cord (a). During this period, the herniated midgut undergoes a counterclockwise rotation of 90° around the SMA, leaving the pre-arterial limb on the right side and the post-arterial on the left (b). During the tenth week of gestation, the midgut quickly returns into the abdominal cavity, while at the same time undergoing a counterclockwise rotation of 90°(c). The last stage of rotation occurs between the tenth and
twelfth week, with a further counterclockwise rotation of 90° (d). In the end, the pre-arterial limb lies to the left of the SMA and the post-arterial limb lies superior and to the right of the SMA (e). Middle congenital mesocolic hernia: between the tenth and twelfth week, the post-arterial limb terminates its rotation prior to 270° (f). Thus, at the twelfth week of gestation, the post-arterial limb remains in a lower position, crossing the SMA anteriorly, and most of the pre-arterial limb is localized behind the transverse mesocolon (g)
Fig. 3 Surgical procedure performed
vascular injuries. Therefore, to remove the obstruction, we resected the incarcerated loop. Intestinal continuity was restored by an ileo-ileal antecolic hand-sewn anastomosis (Fig. 3). Postoperative recovery was uneventful and the patient was discharged 6 days after surgery. No early postoperative or late complications occurred. The patient had complete symptoms resolution at 3, 6, and 12-month reviews.
Discussion
J Gastrointest Surg
pathogenesis of left congenital mesocolic hernias is more , , , controversial. Most authors believe that it is caused,3 5 7 8 during the midgut rotation, by invagination of the small bowel between the posterior wall and a segment of the left mesocolon that therefore fails to fuse and forms the anterior wall of the hernia sac. However, some authors have suggested that primitive fusion failure of the left mesocolon results in a , congenital fossa,1 9 where the small bowel herniates later on. The rare transverse congenital mesocolic hernia results when there is a reversed rotation of the midgut and subsequent invagination of the transverse mesocolon and a portion of the right side of the colon.5 The case reported here is a unique case of congenital mesocolic hernia that has never been previously reported. We hypothesize that, in our patient, during the last stage of the rotation, the pre-arterial limb completed its development and rotated normally, while the post-arterial limb terminated its counterclockwise rotation prior to 270°. Therefore, the post-arterial-limb remained in a lower position, not located superiorly to the SMA, but crossing the SMA anteriorly. Thus, at the twelfth week of gestation, the pre-arterial limb is localized behind the transverse mesocolon, between the MCA and the IMV (Fig. 4). As a result, the portion of the transverse mesocolon between the MCA and IMV, inferiorly to the duodenal-jejunal junction, and anteriorly to the pancreas and the third portion of duodenum, failed to fuse, resulting in a fossa. As the pre-arterial limb continued to elongate, almost all of the small bowel loops became trapped in a sac behind the transverse mesocolon. We believe that this type of internal hernia should be called middle congenital mesocolic hernia based on its pathogenesis. The uncommon presence of internal hernias and the absence of specific clinical features make a clinical diagnosis of congenital mesocolic hernia difficult. CT scan has become the first-line imaging technique in these patients.5 CT scans can demonstrate the encapsulated cluster of small bowel loops within the hernia sac with abnormal location, evidence of obstruction with segmental dilatation or stasis, and displace, , , ment of right, left, or transverse colon.3 4 10 11 In this type of hernia, the mesenteric vessels are commonly engorged, crowded, twisted, and stretched. Additional vascular findings include displacement of the SMA and its branch or displace, ment of the IMV, according to the type of hernia.4 11 In our case, the CT scan was important to arouse suspicion of the presence of an internal hernia and, therefore, to provide an early indication for surgery. The treatment of choice for congenital mesocolic hernias is surgery, which is recommended for all patients fit to undergo laparotomy, due to the high lifetime probability of strangulation and incarceration (50 %).11 In the last few years, laparoscopic treatment has also been reported as a feasible and safe surgical option for the treatment of congenital mesocolic , hernias in selected patients.10 12 The basic management
principles, as for all hernias, are reduction of hernia content , and repair of the defect.3 11 During operation, repositioning of the bowel loops should be performed respecting their correct anatomical location as much as possible and vascular injuries must be carefully avoided as to not compromise the bloody supply of the small and large bowels. However, in our case, given the anatomical anomalies we discovered, it was deemed dangerous to reposition the small and large bowels to their normal anatomical position. In conclusion, congenital mesocolic (paraduodenal) hernias are a rare cause of small bowel obstruction. Herein, we present an unreported type of congenital mesocolic (paraduodenal) hernia: the middle congenital mesocolic hernia. The remote possibility of a congenital mesocolic hernia should be kept in mind by clinicians treating small bowel obstructions in patients with a history of chronic dyspepsia, intermittent colicky abdominal pain, and vomiting, without previous laparotomy. Although the clinical diagnosis is difficult, CT findings can be very useful for arousing suspicion preoperatively. Surgical treatment is always recommended.
References 1. Khan MA, Lo YA, Vande Maele DM. Paraduodenal hernia. Am Surg 1998; 64:1218–1222. 2. Newsom BD, Kukora JS. Congenital and acquired internal hernias: unusual causes of small bowel occlusion. Am J Surg 1986; 152:279–284. 3. Tong RSK, Sengupta S, Tjandra JJ. Left paraduodenal hernia: case report and review of the literature. ANZ J Surg 2002; 72:69–71. 4. Martin LC, Merkle EM, Thomson EM. Review of internal hernias: radiological and clinical findings. AJR 2006; 186:703–717. 5. Willwerth BM, Zollinger RM, Izant RJ. Congenital mesocolic (paraduodenal) hernia. Embryologic basis of repair. Am J Surg 1974; 128:358–361. 6. Frediani S, Almberger M, Iaconelli R, Avventurieri G, Manganaro F. An unusual case of congenital mesocolic hernia. Hernia 2010; 14: 105–107. 7. Berardi RS. Paraduodenal hernias. Surg Gynecol Obstet 1981; 152: 99–110. 8. Moran JM, Salas J, Sanjuán S, Amaya JL, Rincón P, Serrano A, Tallo EM. Paramesocolic hernias: consequences of delayed diagnosis. Report of three new cases. J Pediatr Surg 2004; 39: 112–116. 9. Brigham RA, Fallon WF, Saunders JR, Harmon JW, d’Avis JC. Paraduodenal hernia: diagnosis and surgical management. Surgery 1984; 96:498–502. 10. Bittner JG 4th, Edwards MA, Harrison SJ, Li K, Karmin PN, Mellinger JD. Laparoscopic repair of right paraduodenal hernia. JSLS 2009; 13:242–249. 11. Zonca P, Maly T, Mole DJ, Stigler J. Treitz’s hernia. Hernia 2008; 12: 531–534. 12. Hussein M, Khreiss M, Al-Helou G, Aleaddine M, Elias E, Abi Saad GS. Laparoscopic repair of a left paraduodenal hernia presenting with acute bowel obstruction: report of a case. Surg Laparosc Endosc Percutan Tech 2012; 22:e28-30.
