INTESTINAL MALROTATION & VOLVULUS
Malrotation of the intestines is a developmental abnormality that permits spontaneous abnormal rotation of the midgut around the mesentery (supe-rior mesenteric artery). The incidence of malrota-tion is estimated to be about 1:500 live births. Most patients with malrotation of the midgut present during infancy with symptoms of bowel obstruc-tion. Coiling of the duodenum with the ascending colon can produce complete or partial duodenal obstruction. The most serious complication of mal-rotation, a midgut volvulus, can rapidly compro-mise intestinal blood supply causing infarction. Midgut volvulus is a true surgical emergency that most commonly occurs in infancy, with up to one third occurring in the first week of life. The mor-tality rate is high (up to 25%). Typical symptoms are bilious vomiting, progressive abdominal dis-tention and tenderness, metabolic acidosis, and hemodynamic instability. Bloody diarrhea may be indicative of bowel infarction. Abdominal ultraso-nography or upper gastrointestinal imaging con-firms the diagnosis.
Surgery provides the only definitive treatment of malrotation and midgut volvulus. If obstruction is present but obvious volvulus has not yet occurred, preoperative preparation may include stabilization of any coexisting conditions, insertion of a nasogas-tric (or orogastric tube) to decompress the stomach, broad-spectrum antibiotics, fluid and electrolyte replacement, and prompt transport to the operating room.
These patients are at increased risk for pul-monary aspiration. Depending on the size of the patient, rapid sequence induction (or awake intuba-tion) should be employed. Patients with volvulus are usually hypovolemic and acidotic, and may tolerate anesthesia poorly. Ketamine may be the preferred anesthetic induction agent. An opioid-based anes-thetic can also be used as postoperative ventilation will often be necessary. Fluid resuscitation, likely including blood products, and sodium bicarbonate therapy are usually necessary. Arterial and central venous lines are helpful. Surgical treatment includes reducing the volvulus, freeing the obstruction, wid-ening the base of mesenteric attachments, and resect-ing any obviously necrotic bowel. Bowel edema can complicate abdominal closure and has the potential to produce an abdominal compartment syndrome. The latter can impair ventilation, hinder venous return, and produce renal compromise; delayed fascial closure or temporary closure with a Silastic “silo” may be necessary. A second-look laparotomy may be required 24–48 h later to ensure viability of the remaining bowel.