Rotation Of Midgut Research Articles

Herniation, rotation, looping, and retraction of the midgut occur sequentially during midgut morphogenesis. Recent studies have demonstrated the importance of mechanical forces arising from the differential growth between the midgut and mesentery in the formation of small intestinal loops. However, the roles of mechanics and differential growth in the overall process remain unclear. In this study, we developed a computational model of midgut morphogenesis based on continuum mechanics. We showed that the protrusion, rotation, and retraction of the midgut can emerge sequentially because of temporal changes in differential growth. The midgut was modeled as a hyperelastic tube with a Gaussian shape. The differential growth of the midgut and mesentery was modeled by the spatial variation in spontaneous plastic deformation. The hyperelastic tube developed a protrusion by compression-induced deformation, suggesting that other external forces are not necessary for midgut herniation prior to rotation. Appropriate differential growth induced a rotation of the tube. A less-growing mesentery attempts to face inward to minimize the tensile forces, which causes tube twisting and results in midgut rotation. Excess differential growth may cause the retraction of the midgut before the formation of small intestinal loops. The results of this study will serve as reference in future studies on embryology and tissue engineering.

BACKGROUND Intestinal malrotation (IM) is a rare congenital anomaly resulting from incomplete midgut rotation during embryonic development. Typically, it is diagnosed in infancy due to symptoms such as bilious vomiting, failure to thrive, or signs of bowel obstruction. However, in some cases, it remains undetected until adulthood, when it can present either incidentally or with complications, including volvulus, chronic abdominal pain, or acute bowel obstruction. Although its exact incidence in adults is unclear, studies estimate it to be approximately 0.2% to 0.5%, underscoring its rarity in this age group. As such, adult cases of IM pose a diagnostic challenge and are often discovered unexpectedly during imaging or surgery for unrelated conditions. CASE REPORT A 20-year-old woman with no medical history was admitted to our hospital with persistent mid-abdominal pain. Clinical and sonographic findings suggested acute appendicitis; however, intraoperative exploration revealed an unexpected intestinal malrotation of the non-rotation type. The cecum was in the midline, and the colon was entirely positioned in the left hemi-abdomen, which rendered laparoscopic appendectomy technically challenging. The operation was successfully completed without the need for an additional procedure to correct the malrotation. The postoperative course was uneventful, and the patient was discharged on the second postoperative day in good condition. CONCLUSIONS This case highlights the importance of considering congenital anomalies such as IM in cases of atypically located abdominal structures. Awareness of such anatomical variations is crucial for surgeons so they can adapt intraoperative strategies accordingly and ensure optimal patient outcomes.

The hyaluronan (HA) matrix in the tissue microenvironment is crucial for maintaining homeostasis by regulating inflammatory signalling, endothelial-mesenchymal transition and cell migration. During development, covalent modifications and osmotic swelling of HA create mechanical forces that initiate midgut rotation, vascular patterning and branching morphogenesis. Together with its main cell surface receptor, CD44, HA establishes a physicochemical scaffold at the cell surface that facilitates the interaction and clustering of growth factors and receptors that is required for normal physiology. High-molecular-weight HA, tumour necrosis factor-stimulated gene 6, pentraxin 3 and CD44 form a stable pericellular matrix that promotes tissue regeneration and reduces inflammation. By contrast, breakdown of high-molecular-weight HA into depolymerized fragments by hyaluronidases triggers inflammatory signalling, leukocyte migration and angiogenesis, contributing to tissue damage and fibrosis in kidney disease. Targeting HA metabolism is challenging owing to its dynamic regulation and tissue-specific functions. Nonetheless, modulating HA matrix functions by targeting its binding partners holds promise as a therapeutic strategy for restoring tissue homeostasis and mitigating pathological processes. Further research in this area is warranted to enable the development of novel therapeutic approaches for kidney and other diseases characterized by dysregulated HA metabolism.

Intestinal malrotation (IM) results from an altered or incomplete rotation of the fetal midgut around the superior mesenteric artery axis. The abnormal anatomy of IM is associated with risk of acute midgut volvulus which can lead to catastrophic clinical consequences. The upper gastro-intestinal series (UGI) is addressed as the gold standard diagnosis procedure, but a variable failure degree has been described in literature. The aim of the study was to analyze the UGI exam and describe which features are the most reproducible and reliable in diagnosing IM. Medical records of patients surgically treated for suspected IM between 2007 and 2020 at a single pediatric tertiary care center were retrospectively reviewed. UGI inter-observer agreement and diagnostic accuracy were statistically calculated. Images obtained with antero-posterior (AP) projections were the most significant in terms of IM diagnosis. Duodenal-Jejunal Junction (DJJ) abnormal position resulted to be the most reliable parameter (Se = 0.88; Sp = 0.54) as well as the most readable, with an inter-reader agreement of 83% (k = 0.70, CI 0.49–0.90). The First Jejunal Loops (FJL), caecum altered position and duodenal dilatation could be considered additional data. Lateral projections demonstrated an overall low sensitivity (Se = 0.80) and specificity (Sp = 0.33) with a PPV of 0.85 and a NPV of 0.25. UGI on the sole AP projections ensures a good diagnostic accuracy. The position of the third portion of the duodenum on lateral views showed an overall low reliability, therefore it was not helpful but rather deceiving in diagnosing IM.

Midgut malrotation with volvulus is one of the true surgical emergencies of childhood. Almost all of the studies on anomalies of the midgut rotation and fixation in the literature and related sections in textbooks were designed according to Dott's classification. Focusing only on common rotation anomalies has led to the exclusion and negligence of other rare variants. Isolated pure duodenal non-rotation is such a variant. Herein, we report a case of an unusual variant of isolated pure duodenal non-rotation which presented with signs of midgut volvulus that was successfully treated. Key Words: Newborn, Malrotation, Non-rotation, Isolated duodenal non-rotation, Midgut volvulus.

Background: Intestinal malrotation is a congenital anomaly resulting from abnormal rotation and fixation of an imperfect midgut during embryonic development. This study aims to describe the diagnosis and management of intestinal malrotation and its comorbid diseases in children.
 Case presentation: A boy, aged 9 months, was referred from a regional hospital with complaints of repeated vomiting accompanied by a distended stomach and no bowel movements for 4 days. Based on the birth history, the patient was born with vacuum assistance for the indication of prolonged phase II. The results of the physical examination showed that the patient was seriously ill, with compos mentis, pulse rate 130 x/minute, respiratory rate 34x/minute, blood pressure 90/60 mmHg, temperature 37.6ºC, 99% saturation with the help of O2 nasal canule 2L/minute. There are increased bowel sounds on abdominal examination. Blood examination showed an increase in leukocytes (10.850/mm3). The chest X-ray showed lateral bronchopneumonia, and the abdominal X-ray showed low-lying obstructive ileus. The patient was diagnosed with obstructive ileus due to volvulus, moderate dehydration, comorbid with bronchopneumonia, and global developmental delay.
 Conclusion: Management of intestinal malrotation with volvulus in this patient includes general improvement and rehydration, Ladd's procedure for definitive correction of the cause. Management of comorbid global developmental delay is carried out after the emergency is resolved.

Gastric volvulus in the mediastinum through a hiatal hernia

Intestinal malrotation, a congenital anomaly of rotation of midgut, with paediatric dominant presentation is increasingly being observed in adult population. Here, the severity of presentation ranges from asymptomatic to life threatening midgut volvulus. Presentation with midgut volvulus, managed by an emergency surgery with definitive Ladd’s procedure is the current standard. Presently, there is no data to support elective repair in stable patients with chronic midgut volvulus. Management of asymptomatic adult with malrotation is also a topic of controversy with no recommended guidelines. We herein, present two cases of malrotation with midgut volvulus with initial conservative management followed by elective Ladd’s procedure. Rare associations like nutcracker phenomenon and pancreatitis were also observed in one of our patients. Our study aims to correlate our findings with the published literature, to understand these associations better and to review the need for an emergent operation for chronic midgut volvulus.

Background: Almost all of the studies on anomalies of the midgut rotation and fixation in the literature and related sections in textbooks were designed according to Dott's classification. Focusing only on common rotation anomalies has led to the exclusion and neglect of other rare variants. Isolated pure duodenal nonrotation is such a variant. Case Presentation: We report a case of an unusual form of isolated pure duodenal nonrotation, in a 3-day-old newborn presenting with bilious vomiting. Ultrasonographic examination revealed the sign of 'whirlpool'. When this finding was evaluated together with bilious vomiting, midgut volvulus was considered and the patient was operated on urgently. Peroperatively, it was observed that the jejunum entered between the leaves of the terminal ileum mesentery. Proximally, the duodenum was located posterior to the right colon in a "sack". This "sack" was surrounded by thick Ladd's bands laterally, mesentery of the ascending colon medially, the posterior surface of the cecum and ascending colon anteriorly, and by the posterior abdominal wall posteriorly. Conclusion: In isolated duodenal nonrotation, the duodenum may be completely retro-colic. Consequently, the duodenojejunal junction and the ileocecal region may almost overlap. Unlike isolated duodenal nonrotation cases, in the surgical treatment of this variant, separation of Ladd bands alone is not sufficient, additionally, the right colon should be placed in a nonrotation position and care should be taken not to kink the terminal ileum under the cecum.

Intestinal malrotation is partial or complete failure of 270% counterwise rotation of midgut around the superior mesenteric vessels in embryonic life. Malrotation can present in any age group. Most of the patients present within rst month of life. However late presentation is rare, we present a case report of 58 yr female with tuberculosis transverse colon mass with malrotation with ladd's band with sub acute intestinal obstruction. She presented with epigastric pain,mass and vomiting. Patient underwent laaproscopic ladd's procedure and descending colon and ileum bypass with Ileo Descending anastomosis , She had good postoperative recovery. In this article we describe our experience in creating descending colon and ileum bypass with Ileo Descending anastomosis.

Abstract Aim Midgut malrotation is a rare but a very well-known congenital anomaly. It is a result of non-rotation, incomplete rotation or reversed rotation and fixation of midgut. Delayed diagnosis due to non-specific symptoms in elective cases and conversion to laparotomy due lack of intra-operative anatomical understanding in emergency cases imposes increase in patient dis-satisfaction, delayed recovery and healthcare cost burden. Here we report an interesting case series which impose a significant diagnostic challenge due to atypical clinical and radiological signs. Management of such cases by minimal invasive surgery is possible if general surgeons are aware of unusual anatomy and general practitioners are aware of such known but rare cases. Cases Two patients who presented on background of on and off recurrent non-specific attacks of abdominal pain, one of them as an emergency as midgut volvulus, were diagnosed radiologically and treated laparoscopically. The other one presented as an acute appendicitis and was converted to laparotomy, in spite of good laparoscopic expertise due to lack intra-operative anatomical understanding. Conclusion In the era of laparoscopic surgery, a general surgeon should encounter such an unusual case once in a lifetime. It is of paramount importance to be well verse with such unusual cases. General Practitioners should be aware of such atypical presentations of rare conditions causing recurrent abdominal pain. They should consider appropriate further imaging investigations and referrals for best possible patient care.

Intestinal malrotation is a rare fetal anomaly resulting from the failure of midgut rotation and fixation. Sonography is typically the first modality of choice for assessing pediatric pathology due to its high sensitivity, portability, real-time imaging capability, and non-ionizing technique; however, its role in diagnosing small bowel rotational anomalies remains limited and controversial. Fluoroscopic upper gastrointestinal imaging (UGI) is the primary diagnostic examination at most institutions. However, even on UGI, imaging findings may be equivocal. In such cases, sonography may provide additional information at facilities where it is not used as a primary diagnostic tool. This case report represents the first reported case showing how patient position is important as the typical vascular sonographic features of rotation were normal in one position but abnormal in another. In addition, this case shows how congenital intestinal malrotation was decisively diagnosed using sonographic imaging.

Mal rotation of midgut is associated with other anomalies usually encountered in neonatal period or early childhood. If undetected in childhood it presents in adulthood with small bowel obstruction, repeated appendicitis or chronic abdominal symptoms. CECT abdomen is mandatory for diagnosis though it often presents as surgical surprise on abdominal laparotomy. Hereby, we presented 3 cases where it was undetected till adulthood though CECT was mandatory for definitive diagnosis. Case 1 patient presented with chronic abdominal pain on left abdomen was actually malrotation with appendix lying on left hypochondrium and stenosed fourth part duodenum adding to vomiting off and on. Case 2 patient in adulthood presented with repeated sub-acute intestinal obstruction because of midgut mal-rotation. Relieved after Ladd band was cut and obstructive symptoms relieved. Case 3 patient had inflammed appendix in subhepatic position was cause of chronic pain with para duodenal hernial sac adding to intestinal obstruction with malrotation of midgut.

Intestinal malrotation is the partial or complete failure of rotation of midgut around the superior mesenteric artery, while Meckel’s diverticulum is the remnant of vitellointestinal duct and concurrence of these congenital abnormalities in an adult is considered a rarity. Till date only 3 cases of concurrent intestinal malrotation and Meckel's diverticulum have been reported. We report a 18 years male who presented with a 3 day history of abdominal pain, bilious vomiting, obstipation and chronic abdominal pain on and off since 3 years of age. During the last episode which occurred 1 year back, he was diagnosed with intestinal malrotation with subacute intestinal obstruction and was treated conservatively. Examination revealed the presence of signs of peritonitis. After resuscitation, CECT abdomen was taken which showed dilated small bowel loops in the subhepatic region associated with malrotation. Emergency laparotomy revealed a Ladd's band below which the gangrenous small bowel loops 150 cm from the duodenojejunal (flexure until 5 cm proximal to the ileocecal junction) were found herniating into the subhepatic region with a Meckel’s diverticulum and a right sided DJ flexure. We proceeded with the band release and resection of gangrenous bowel followed by proximal jejunostomy with distal ileostomy. HPE was consistent with Meckel’s diverticulitis without any ectopic gastric or pancreatic mucosa. Ostomy reversal was done after 8 weeks. Patient had an uneventful postoperative recovery during both the admissions and he is on regular follow-up now.

Background: Intestinal malrotation refers to the partial or complete failure of rotation of midgut around the superior mesenteric vessels in embryonic life. Arrested midgut rotation results due to narrow-based mesentery and increases the risk of twisting midgut and subsequent obstruction and necrosis. Midgut volvulus secondary to intestinal malrotation is a rare presentation in adults more so in the elderly. Its rarity portends a diagnostic dilemma for both the surgeon and radiologist, and CT scan showed dilated large and small intestine segments with air-fluid levels and twisted mesentery around superior mesenteric artery and vein indicating "whirlpool sign". In our patient Case presentation: 42 years old male who presented to the emergency department with acute onset of pain in the RUQ, vomiting, and absolute obstipation for the last 2 days. This patient had a history of similar two episodes of sub-acute intestinal obstruction in the last 6 months which has been managed conservatively. The patient underwent an elective exploratory laparotomy after 2 days of failed conservative management. Operative findings included the presence of adhesive bands in the RUQ (Ladd's Band), volvulus of the mid-portion of the small bowel in a clockwise fashion, and multiple intraabdominal adhesions and empty RIF and caecum pulled up in RUQ. We subsequently performed a Ladd's procedure, multiple adhesiolysis, and caecopexy and the patient had an uneventful recovery with eventual discharge on postoperative day 12. This case report reviews the incidence of malrotation in adults. It also high Conclusion: lights the difficulty in diagnosing midgut volvulus in the adult population given the nonspecific, insidious symptoms, therefore, prompting awareness of its existence and a high degree of clinical suspicion. Malrotation should be considered in the differential diagnosis in patients presented with acute abdomen and intestinal ischemia.

We report the case of treatment of a 30-year-old woman with an impaired passage in the duodenojejunal segment of the gastrointestinal tract due to Ladd’s syndrome. Occlusion of the superior mesenteric artery was developed as a result of incomplete rotation of midgut in dysembryogenesis. Mesenteric blood circulation was compensated by collaterals formed in the antenatal period. Ladd’s operation was performed to treat acute intestinal failure, the duodenojejunal passage was restored. The patient was discharged on the 11th postoperative day in a good condition with the main diagnosis «Ladd’s syndrome». In the presented case report, the impaired passage in the gastrointestinal tract in the middle age patient was traced from childhood. Detailed examination of medical history, correct interpretation of MSCT findings allowed to form an accurate diagnosis and perform effective surgical treatment.

Sigmoid colon is a part of large intestine and normally measures 15” in length that extends from the pelvicbrim to the third piece of the sacrum where it becomes the rectum. Dolicho sigmoid or redundant sigmoid colon is a term used for sigmoid colon longer than its normal size. The present case had a displaced descending colon and a redundant part of sigmoid colon. During a routine dissection class for medical students, an anatomical variation related to sigmoid colon in an 87-year-old male cadaver was found. The colon was carefully dissected and studied in detail the position, attachment of sigmoidmesocolon, examination of viscera in close proximity and the blood supply to each part of the large intestine. A meticulous review of the literature was conducted as well. An anomalous displacement of descending and sigmoid colons wasfound. The descending colon is normal in length, retroperitoneal and lying close to the midline leaving out a space to its left that was occupied by loops of jejunum and ileum. The sigmoid colon is composed of redundant ascending and normal descending parts. The redundant part of the sigmoid colon is centrally placed as a loop ascending into the peritoneal cavity reaching the splenic flexure at the level of T11 approximately. The descending part of the sigmoid colon crosses the midlineat L1 and runs close to the right midclavicular line continuing as rectum. The total length of sigmoid colon measures 23.2”. The blood supply to the redundant part of the sigmoid comes from a common trunk arising from inferior mesenteric that splits into leftcolic and two additional sigmoid branches. The blood supply to the descending part of sigmoid is supplied by sigmoidal artery coming directly from inferior mesenteric artery. The branching pattern of sigmoidal arteries compared to previous cases in the literature makes this case very unique. Embryology of gut development is complex and often unpredictable, leading to variations in length and position. The growth and rotation of midgut is divided into four stages. An excess of growth of the caudal segment of gut tube in stage 3 can cause redundant sigmoid. This variation could increase the chances of sigmoid volvulus, constipation and may pose risk as the loops may coil around and form a knot leading to obstruction. A redundant loop of sigmoid colon may be asymptomatic or it might lead to urinary, digestive and vascular complications. The descending colon is normal in length but lies close to the midline which may compress the aorta when loaded with feces. Radiologists and surgeons must be well aware of these variations to establish a correct diagnosis and assert the appropriate management when performing colonoscopy, sigmoidoscopy and abdominopelvic procedures.

Abstract Introduction/Objective Enteropathy Associated T-Cell Lymphoma (EATL) is a rare and aggressive subtype of primary intestinal T cell lymphoma which occurs in patients with Celiac Disease (CD), most prevalent in the western world with an incidence rate of 0.22-1.9 cases per 100,000. The classic immophenotype of these neoplastic intestinal T cells show loss of CD8 and CD56. The adherence to gluten-free diet, markedly decreases the incidence of this complication. Methods The patient’s previous and current biopsies, autopsy and EMR were reviewed. The patient is 66-year female that was diagnosed with Celiac Disease in 2003 after duodenal biopsy showed features suggestive of CD with positive anti-endomysial IgA antibody serology. She presents currently with burning abdominal pain, with subsequent CT scan showing a mass in the small bowel with mid gut rotation and lesions in the lungs, liver and bladder. Endoscopy showed multiple lesions extending from the hypopharynx to the large bowel, which on biopsy showed CD3+ lymphocytes expanding the lamina propria and infiltrating the crypt epithelium. Given the patient’s clinical history a diagnosis of EATL was made. The patient passed 5 days after diagnosis due to small bowel perforation. Results The initial duodenal biopsy showed villous blunting and increased intraepithelial lymphocytes. The biopsies of the gastrointestinal lesions show abnormal infiltrate of pleomorphic, intermediate in size lymphocytes with round to irregular and occasionally cleaved nuclei with pale to clear cytoplasm. These cells infiltrate the crypt epithelium. The immophenotype of these neoplastic cells are positive for CD3, CD7, CD8, CD56, TIA-1 and BF1, while negative for CD4, CD5 and CD30. T cell clonality was also positive. In addition to the above lesions, autopsy revealed involvement of an area of small bowel perforation with full-thickness mucosal wall involvement by the neoplastic cells. In addition, there is widely dissemenated disease involving the lung, liver, bone marrow, spleen, mesenteric lymph nodes, omentum, bladder, ovaries and myometrium (first report of uterine involvement). Conclusion CD8 positive EATL may occur in 19-30% of cases, and increases up to 50% in refractory CD. The differential diagnosis of MEITL, which is typically CD8 positive, is important and most be distinguished on the basis of clinical setting in the presence of Celiac Disease.

Sigmoid colon is a part of large intestine and normally measures 15” in length that extends from the pelvic brim to the third piece of the sacrum where it becomes the rectum. Dolichosigmoid or redundant sigmoid colon is a term used for sigmoid colon longer than its normal size. The present case had a displaced descending colon and a redundant part of sigmoid colon. During a routine dissection class for medical students, an anatomical variation related to sigmoid colon in an 87‐year‐old male cadaver was found. The colon was carefully dissected and studied in detail the position, attachment of sigmoid mesocolon, examination of viscera in close proximity and the blood supply to each part of the large intestine. A meticulous review of the literature was conducted as well. An anomalous displacement of descending and sigmoid colons was found. The descending colon is normal in length, retroperitoneal and lying close to the mid‐line leaving out a space to its left that was occupied by loops of jejunum and ileum. The sigmoid colon is composed of redundant ascending and normal descending parts. The redundant part of the sigmoid colon is centrally placed as a loop ascending into the peritoneal cavity reaching the splenic flexure at the level of T11 approximately. The descending part of the sigmoid colon crosses the midline at L1 and runs close to the right midclavicular line continuing as rectum. The total length of sigmoid colon measures 23.2”. The blood supply to the redundant part of the sigmoid comes from a common trunk arising from inferior mesenteric that splits into left colic and two additional sigmoidal branches. The blood supply to the descending part of sigmoid is supplied by sigmoidal artery coming directly from inferior mesenteric artery. The branching pattern of sigmoidal arteries compared to previous cases in the literature makes this case very unique. Embryology of gut development is complex and often unpredictable, leading to variations in length and position. The growth and rotation of midgut is divided into four stages. An excess of growth of the caudal segment of gut tube in stage 3 can cause redundant sigmoid. This variation could increase the chances of sigmoid volvulus, constipation and may pose risk as the loops may coil around and form a knot leading to obstruction. A redundant loop of sigmoid colon may be asymptomatic or it might lead to urinary, digestive and vascular complications. The descending colon is normal in length but lies close to the midline which may compress the aorta when loaded with feces. Radiologists and surgeons must be well aware of these variations to establish a correct diagnosis and assert the appropriate management when performing colonoscopy, sigmoidoscopy and abdominopelvic procedures.Support or Funding InformationDepartment of Anatomy Touro College of Osteopathic MedicineThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

BackgroundIntestinal malrotation, which arises from incomplete rotation of the embryonic midgut, is one of the congenital anomalies usually diagnosed in infancy. On the other hand, intestinal malrotation detected in asymptomatic adults is very rare. It is frequently diagnosed incidentally during abdominal surgery. We report a case of asymptomatic intestinal malrotation diagnosed during laparoscopic distal gastrectomy for gastric cancer.Case presentationA 59-year-old female was diagnosed with early-stage gastric cancer during health screening and admitted to our hospital for radical surgical treatment. Physical examinations and blood tests revealed nothing of note. The type 0-IIc gastric cancer was located in the posterior wall of the mid-body of the stomach. The histological type was poorly differentiated adenocarcinoma.Esophagogastroduodenoscopy and computed tomography (CT) suggested that the depth of tumor invasion was the submucosal layer without regional lymph node swelling. The clinical stage according to the TNM 7th edition was cT1b N0 M0, cStage I.Laparoscopic distal gastrectomy with D1+ lymph node dissection and Billroth-I method reconstruction was planned. During the infrapyloric lymph node dissection, a part of the pancreatic head showed unusual adherence to the first part of the duodenal wall. For safe and accurate lymphadenectomy while avoiding pancreatic injury, we deliberately focused on tracing the dissectible layer between the pancreatic parenchyma and fatty tissues including lymph nodes.Also, we changed the reconstruction procedure from Billroth-I to Roux-en-Y. After distal gastrostomy, we could not find the ligament of Treitz or jejunum on the left side below the transverse colon. Based on a review of the CT image, this patient was diagnosed with intestinal malrotation.Although the detection of malrotation during the operation was incidental, we could complete radical surgery and Roux-en-Y reconstruction safely. The type of malrotation was non-rotation (90°). She was discharged from our hospital without any complications.ConclusionWe encountered a case of adult asymptomatic intestinal malrotation with gastric cancer. Even when encountering such a case during laparoscopic gastrectomy, reviewing CT images carefully to reconsider the anatomical anomalies, and tracing the dissectible layer accurately with adequate countertraction can facilitate safe and successful surgery.