The patient, male, 35 years old, was admitted to the hospital with “recurrent vomiting for 4 months”. 4 months ago, vomiting of unknown origin, which was gastric contents, with bile and persistent food in severe cases, was relieved by fasting and fluids. Recently, the symptoms worsened and he was hospitalized with “duodenal obstruction” for further diagnosis and treatment. Gastroscopy, gastrointestinal imaging, MRI and other examinations suggested that the duodenal obstruction was dilated, and the horizontal part was in the right iliac fossa (see figure). After preoperative preparation, “dissection and Ladd operation” was performed. Intraoperatively, the small intestine was seen to rotate clockwise around the mesentery to the dilated duodenal obstruction, which was diagnosed as intestinal malrotation. The Ladd’s cord and abdominal adhesions were released, the rotated intestine was repositioned, the ascending colon and transverse colon were placed in the left abdominal cavity, the small intestine was placed in the right abdominal cavity, and the appendix was removed. The postoperative recovery was smooth, and the patient started to eat after venting on the 2nd postoperative day without vomiting, and was discharged on the 4th day, with no symptoms at the 3-month follow-up.
Congenital intestinal malrotation is a complication of intestinal obstruction or intestinal torsion due to incomplete or abnormal rotational movements of the intestinal tube during embryonic development, i.e., the superior mesenteric artery (SMA) is the axis of rotation, resulting in variation in the position of the intestine and incomplete attachment of the mesentery. It occurs in 80% of neonates, a few in infancy or childhood, and is very rare in adulthood. The incidence is one times higher in males than in females.
There are various types of malrotation of the intestine. The midgut is abnormally rotated 180° clockwise so that the duodenojejunal flexure is in front of the superior mesenteric artery (Figure C), while the proximal colon is rotated in a clockwise direction behind the superior mesenteric artery and the small intestinal mesentery, and the cecum continues to travel to the lower right abdomen resulting in the middle of the transverse colon remaining behind the artery, which is the case here. If the proximal midgut continues to rotate an additional 180° in a clockwise direction with the superior mesenteric artery as the axis, the duodenojejunal flexure moves to the left posterior aspect of the superior mesenteric artery, at which point the cecum migrates and stays in the left abdominal cavity.
Diagnosis: Based on clinical manifestations, x-ray imaging, gastroscopy, CT or MRI, the diagnosis can mostly be obtained.
(1) Upright plain film of the abdomen: it can show enlarged stomach and duodenum or a double bubble sign, and reduced air content in the small intestine. Significant dilatation of intestinal lumen with stepped fluid level suggests possible closed-collateral obstruction or intestinal necrosis.
(2) Barium enema examination: conventional barium enema examination shows abnormal position of the cecum or colon as the x-ray feature of the disease.
(3) Upper gastrointestinal imaging: small bowel dysplasia has abnormal duodenal or duodenojejunal curvature and jejunal position, and upper gastrointestinal imaging has more diagnostic value (Figure A).
(4) Ultrasound examination of the abdomen to localize the superior mesenteric artery (SMV) has important diagnostic value for this disease. When small bowel malrotation is present, ultrasound examination shows that the SMV is not anterior to the inferior vena cava, but displaced to the anterior side of the abdominal aorta, directly in front of the SMA or to the left (e.g., Figure C).
(5) CT and MRI examinations have the same significance as ultrasound for the localization of the superior mesenteric vessels.
Treatment: Asymptomatic patients can be operated without surgery and left for observation. If the symptoms of obstruction or acute abdominal pain are indications for surgery, early surgery should be performed after making the necessary pre-surgical preparations. Signs of intestinal bleeding or peritonitis suggest the occurrence of torsion and must be treated urgently.
1. Preoperative preparation
(1) For acute high intestinal obstruction with dehydration, preoperative fluid replacement and correction of acid-base imbalance should be carried out rapidly. With blood in stool, abdominal distension and symptoms of peritoneal irritation suggesting reversal, actively prepare for immediate surgery for 1 to 2h.
(2) For chronic incomplete obstruction with malnutrition and anemia, prepare for 3 to 5 days before surgery, with daily gastric lavage, intravenous fluids, plasma or amino acids, and for anemia, whole blood should be transfused, and operate as soon as possible after correcting anemia and malnutrition.
(3) The surgeon should be familiar with the various pathological and complication characteristics of this malformation before surgery in order to perform the surgery correctly. 2. Surgical principles: Release the obstruction and restore the patency of the intestine.
Surgery includes the following steps.
(1) General mesenteric surgery: If the position of the intestinal canal is normal and there is a general mesentery, fix the cecum and ascending colon on the right lateral posterior peritoneum of the abdominal cavity and intermittently suture the posterior lateral plasma membrane layer of the colon to the posterior peritoneum with fine silk sutures, which should be tightly arranged to prevent abnormal movement of the right hemicolectum. The ascending colonic mesentery was slanted from the ileocecal valve toward the duodenojejunal flexure, and mattress sutures were made on the dorsal side of the mesentery and the retroperitoneum to fix the colonic mesentery. (2) Intestinal repositioning: when all the small intestine is raised outside the incision, it can be found that the small intestine is twisted at its mesenteric root, and the cecum and part of the colon are also twisted and wrapped around the mesenteric root, and the twisting is often clockwise. The torsion can be 360° to 720°. At this time, the color of the small intestine becomes better and the intestinal cavity is inflated, but the duodenal obstruction is not completely lifted.
(3) Cecum loosening: after the above small intestine reset, we can see that the cecum is located in the right upper abdomen, covering the duodenum, or the peritoneal belt connecting the cecum and the colon compresses the 2nd and 3rd part of the duodenum and causes duodenal obstruction. Therefore, an appendiceal release is required to cut the peritoneal band close to the right side of the cecum and free the cecum and colon to the left, so that the covered duodenum can be exposed (both Ladd surgery).
(4) Reverse intestinal rotation surgery: The twisted intestinal canal should be rotated 360° in the anti-clock direction to turn the transverse colon behind the artery to the front of the superior mesenteric artery during the revision. To prevent the turned transverse colon from compressing the duodenum, all adhesion cords near the duodenojejunal flexure should be released first, and the duodenum should be straightened so that it is displaced to the right abdominal cavity with the beginning of the jejunum.
(5) Mesenteric hernia surgery Colonic mesenteric hernia may be accompanied by incomplete rotation of colonic collaterals, with the cecum and ascending colon staying in the upper abdomen, so ladd surgery should be performed first, freeing and pushing the cecum and ascending colon to the left side, revealing the opening of the hernia sac behind it, carefully cutting the edge of the hernia sac at a non-vascular place, enlarging the hernia opening, removing and straightening the small intestine inside the sac, sewing the hernia sac opening, and fixing the wall of the hernia sac to the posterior peritoneum. As there is a colonic artery running along the anterior edge of the wall of the colonic mesenteric hernia, the small intestine inside the hernia sac should not be cut open or removed arbitrarily to avoid damaging the blood vessels.
(6) Appendectomy: After Ladd’s operation, the ileocecal part is finally located in the left side of the abdomen, and if appendicitis occurs in the future, it will lead to difficulties in diagnosis and treatment, so the appendix should be removed incidentally.
Prognosis: The outcome of surgery for simple intestinal malrotation is satisfactory. In combination with intestinal torsional dysplasia without intestinal necrosis, chronic abdominal pain, digestive and absorption dysfunction, anemia and malnutrition may remain after surgery. In case of intestinal torsional necrosis with extensive resection of the small intestine, short bowel syndrome may occur after surgery, requiring long-term extra-gastrointestinal nutrition to maintain life.