Medical Care
Reversing or removing the precipitating factor is usually successful in a patient with acute superior mesenteric artery (SMA) syndrome. Conservative initial treatment is recommended in all patients with superior mesenteric artery syndrome; this includes adequate nutrition, nasogastric decompression, and proper positioning of the patient after eating (ie, left lateral decubitus, prone, knee-to-chest position, or Goldthwaite maneuver). [19] Enteral feeding using a double lumen nasojejunal tube passed distal to the obstruction under fluoroscopic assistance is an effective adjunct in treatment of patients with rapid severe weight loss and also eliminates the need for intravenous fluids and the risks associated with total parenteral nutrition.
In some instances, both enteral and parenteral nutritional support may be needed to provide optimal calories. The patient's weight should be monitored daily. Subsequently, the patient can be started on oral liquids followed by slow and gradual introduction of small and frequent soft meals as tolerated. Finally, regular solid foods are introduced. Metoclopramide treatment may be beneficial. Review of the orthopedic literature reveals that the success rate is 100% with medical management only in cases with an acute presentation of SMA syndrome.
Surgical Care
Surgical intervention is indicated when conservative measures are ineffective, particularly in patients with a long history of progressive weight loss, pronounced duodenal dilatation with stasis, and complicating peptic ulcer disease. A trial of conservative treatment should be instituted for at least 4-6 weeks prior to surgical intervention.
Options for surgery include a duodenojejunostomy or gastrojejunostomy to bypass the obstruction or a duodenal derotation procedure (otherwise known as the Strong procedure) to alter the aortomesenteric angle and place the third and fourth portions of the duodenum to the right of the superior mesenteric artery. [12] This is called derotation because the final position of the midgut is in direction opposition to the normal embryonic rotation of the midgut. This may be best suited for pediatric patients in whom the superior mesenteric artery syndrome may be related to congenital anatomic conditions that predispose to their symptomatology. [12]
Surgical duodenal derotation for superior mesenteric artery syndrome usually requires a laparotomy, during which the duodenum is mobilized after division of the ligament of Treitz. Once the duodenojejunal junction has been fully mobilized, the jejunum is passed behind the superior mesenteric artery and is positioned to the right of the superior mesenteric artery so it does not lie in the acute angle between the aorta and the superior mesenteric artery. [12, 20] This procedure can also be done laparoscopically and can be converted to a gastrojejunostomy or duodenojejunostomy if it fails to improve the patient's symptoms.
Another surgical approach to treating superior mesenteric artery syndrome is a duodenojejunostomy, in which the compressed portion of the duodenum is released and an anastomosis is created between the duodenum and jejunum anterior to the superior mesenteric artery. This is the classic approach to superior mesenteric artery syndrome. Advantages include the ease of procedure. Complications include risk of bleeding, leakage or stricture at the anastomotic site, and a creation of a nonphysiologic bilious circulation loop of unknown consequence. [12]
Successful laparoscopic duodenojejunal bypass has been described. The operation consists of a loop of jejunum anastomosed to the dilated duodenal segment, which is seen below the transverse mesocolon. Although experience is limited to case reports and small studies, laparoscopic approaches are feasible and provide a less invasive surgical option. [21, 22, 23] A gastrojejunostomy may be another surgical option but is usually reserved for patients who have contraindication to a duodenojejunostomy, such as duodenal ulcer disease or if both the stomach and duodenum are severely dilated. [12] Care in pursuing surgical correction should be taken in patients with significant premorbid conditions and malnutrition, such as end-stage renal disease, because these have a high surgical mortality when performed for superior mesenteric artery syndrome. [24]
A retrospective study evaluated 12 patients with superior mesenteric artery syndrome who were treated with laparoscopic enteric bypass. The study concluded that laparoscopic duodenojejunostomy is safe and effective and should be considered the optimal treatment for patients presenting with duodenal obstruction from superior mesenteric artery syndrome. The study also concluded that advances in minimally invasive surgery have demonstrated the safety and low morbidity of laparoscopically created enteric anastomoses. The authors add that the shorter hospital stay, low morbidity, and that the high success of laparoscopic enteric bypass make this approach favorable to traditional open techniques. [25, 26] A retrospective chart review by Chang et al on patients who underwent minimally invasive duodenojejunostomy found that at follow-up only 6 of 18 patients reported symptomatic improvement or resolution even though 14 of 18 patients reported initial symptom improvement. [27]
Consultations
The following consultations may be indicated:
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Pediatric gastroenterologist
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Nutritionist [28]
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Pediatric surgeon
Diet
Medical therapy usually begins with the initiation of intravenous fluids and, once no significant emesis, with the frequent administration of small amounts of liquids. In some cases, nasojejunal or nasogastric tube feedings with a standard liquid diet may be indicated. If the patient is completely obstructed or unable to tolerate liquids, total parenteral nutrition is indicated.
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Prompt gastric emptying of residual contrast is present within the stomach into the second portion of the duodenum. Additional contrast was hand injected through the transpyloric feeding tube to further distend the second portion of the duodenum. The second portion of the duodenum is dilated with very slow transit across the spine into the jejunum. This occurred despite difference in position of the patient. The high-grade partial obstruction at the distal second portion of the duodenum is due to superior mesenteric artery (SMA) syndrome.
