Cases with adhesions (%)
Congenital diaphragmatic hernia
Aggregate (mean) incidence of ASBO in general surgery of childhood.
Case with adhesions (%)
Small bowel surgery
Intra-abdominal adhesions are the result of traumatic or congenital scar formation between two normally unattached peritoneal surfaces . Operative techniques resulting in tissue trauma, intra-abdominal infections, inflammation, hemoperitoneum, foreign bodies, and exposure to radiation are risk factors for adhesion formation [9, 10]. Deposits of a fibrin matrix gel form between two injured surfaces. Insufficient fibrinolysis in the postoperative state inhibits reabsorption of these deposits. Adhesions form when the extracellular collagenous matrix of the fibrin bands is infiltrated with fibroblasts, smooth muscle cells, neovascularization, and occasionally nerve endings . The presence of peritonitis or active inflammation at the initial operation has a higher rate of dense adhesions [6, 7, 11].
Best practice guidelines for the diagnosis and clinical management of ASBO have only been published for the adult population . However, the initial management in children is similar to adults . Diagnosis of ASBO in children requires a thorough history and physical exam.
Crampy abdominal pain, nausea, vomiting, bloating, and obstipation are the most frequent symptoms of ASBO. The time course of symptoms and the quality of emesis should be clarified. It is important to have a clear understanding of prior operations, operative approach (i.e., open versus laparoscopic), and underlying pathology. History of constant abdominal pain and lethargy is concerning.
Abdominal distention and high-pitched or absent bowel sounds can be encountered; however, these signs may not be present with a higher level of obstruction or at an early presentation. It is important to examine healed surgical incisions and bilateral groins for hernias. Altered mental status, abdominal tenderness, distention, peritonitis, tachycardia, and fever are potential signs of bowel ischemia. Patients should be evaluated for signs of hypovolemia including poor capillary filling, mottling, cool skin with reduced turgor, dry mucus membranes, and sunken anterior fontanelle (infants). It is important to be aware that lethargy can prevent a reliable abdominal exam, especially in small children and infants .
Laboratory evaluation should include white blood cell count (WBC count), electrolytes, and BUN/creatinine. Elevation of WBC is a concerning for ischemia but may also be seen in dehydration.
Upright and supine plain abdominal films are standard to detect the presence of air fluid levels, distended loops of small bowel, and paucity of gas in the colon . The risks compared to benefits of CT scan utilization in the diagnosis of ASBO in children are not well understood . A small retrospective review by Wang et al. of 47 surgically proven ASBO cases reported a 91.5 % sensitivity with 78 % correct identification of location and 68 % identification of cause of ASBO using multidetector CT scan in children . It is important to note that CT utility is decreased in infants and small children with less fat and can be difficult to interpret. CT scan in obstructed adults has a 95 % sensitivity and specificity in high-grade obstructions with transition point localization and identification of ischemia . While not recommended as routine in adults, CT can predict failure of nonoperative management by identifying free intraperitoneal fluid, paucity of gas in the colon, mesenteric edema, lack of the “small bowel feces sign ,” and evidence of devascularized bowel . Children are more susceptible to the long-term consequences of radiation, and CT scan should only be judiciously used in obstructed children with a concern for a concurrent intra-abdominal abscess or diagnostic uncertainty .
Absolute indications for emergent surgery include patients in extremis, signs of bowel ischemia, peritonitis, or perforation . Initial management of children with ASBO without indications for immediate surgical exploration is debated [16, 17]. It is established that adults with partial ASBO can safely undergo nonoperative management , but no trials exist to direct conservative management in children. Management of pediatric ASBO has traditionally been more aggressive. Review of the Kids’ Inpatient Database (KID) data from 2003 to 2006 reported 85.5 % operative rate in children ages 2–20 admitted with ASBO . Conservative management consists of nasogastric decompression, parenteral fluids, correction of electrolytes, and serial abdominal exams. Surgery is indicated if the patient’s exam worsens; the patient develops signs of ischemia/perforation, or if the patient does not improve with medical management. A systematic review of conservative management in children with ASBO reported a range of success from 0 to 75 % . Study variations, patient age, severity of presentation, and clinical resources (two studies reported limited capacity for parenteral fluids) likely account for the range. Conservative management in children less than 1 year of age has been noted to have a higher failure rate [20, 21]. Over half of studies report a success rate of conservative management in more than 50 % of patients. Patients successfully managed conservatively had a shorter hospitalization and time to feeding . This review suggests that conservative management of ASBO can be effective in children.
Review of the KID data found a 1.67 odds ratio of small bowel resection with operative intervention delayed until hospital day 3–14, and no difference in small bowel resection between operating on day 1 versus day 2. It is recommended that stable patients without concerning signs of perforation, strangulation, or peritonitis can be safely managed conservatively for 48 h in children over 2 years and 24–48 h in children less than 2 years of age . It is crucial that these patients are closely observed for signs of deterioration in either their physiology or abdominal exam and receive prompt operative management at recognition of these changes. If patients do not improve over the observation period, it is recommended that they also receive operative intervention .
An increasing body of literature supports the use of Gastrografin in adults with ASBO as an adjunct to conservative therapy. Visualization of contrast in the cecum 4–24 h after administration has a 96 % sensitivity and 98 % specificity for nonoperative resolution in adults . It is currently controversial if Gastrografin is simply a diagnostic aid or is therapeutic in partial ASBO. It is possible that the high osmolarity shifts fluid into the obstructed bowel creating a pressure gradient to relieve the obstruction . Two small observational pediatric studies reported 85 % and 75 % of children with ASBO successfully resolved nonoperatively with Gastrografin after failing 48 h of conservative therapy [24, 25]. While the evidence for the use of Gastrografin in pediatric ASBO is limited, it appears to be safe and should be further investigated.
Bastug first reported laparoscopic adhesiolysis for ASBO in 1991 . Decades later, evidence for laparoscopy in ASBO is limited in adults  and sparse in children with only observational studies [28–32]. Analysis of KID data found an increase in the rate of laparoscopic lysis of adhesions (LOA) for ASBO from 7.2 to 17.2 % between 1997 and 2009 . This same analysis found a lower complication rate, shorter length of stay, lower total hospital cost, and lower puncture/laceration incidence with a conversion rate less than 2 % . This suggests the laparoscopic approach is safe although current publications do not identify patient characteristics for successful laparoscopic use [28–32]. The incidence of postoperative adhesions is decreased with a laparoscopic technique in any surgery, further supporting this method . Pooled analysis of laparoscopic adhesiolysis for adult ASBO found decreased mortality, morbidity, pneumonia, wound infections, and length of stay. While laparoscopic operative time was longer, there was no difference in the rates of bowel injury or reoperation .
The only absolute contraindications to laparoscopic adhesiolysis are patient intolerance of pneumoperitoneum or inability to safely place ports due to distention. Relative contraindications may include history of multiple procedures, peritonitis, free air, or stranulaged/gangrenous bowel though these case may be started laparoscopically and converted if needed. All other patients with surgical indications treated by an experienced laparoscopic surgeon may have an initial laparoscopic attempt after adequate resuscitation.
Single-band adhesions are present in 70 % of children with ASBO and have higher laparoscopic success rates . Although, single bands are difficult to predict as the severity of adhesions is not correlated with the scale of the initial operation. Patients with a history of multiple procedures tend to have more adhesions, which should be taken into consideration before attempting a laparoscopic approach. Bowel distention over 4 cm and distal obstructions are associated with converstion to laparotomy.
The patient is positioned supine with placement of a nasogastric tube and a urinary catheter. Decompression with nasogastric aspiration for several hours prior to the procedure can alleviate bowel distention in some cases and improve visualization. The ability to tilt the patient intraoperatively in various directions is important to allow visualization of certain areas of the abdomen depending on the location of the adhesions. For example, the use of reverse Trendelenburg in a patient with a prior upper abdominal surgery facilitates exposure to the upper abdomen.