There is a wide spectrum of neonatal conditions having in common an intestinal obstruction by ispissated endoluminal content, in absence of mechanical obstacle, CF or HD. Rickman and Boeckman, in 1965, first reported a neonatal meconium obstruction in absence of CF and Vinograd et al, in 1983, reported the first series of this syndrome in LBW. Kubota at al . were the first to propose the term "Meconium Related Ileus" MRI to cover the so called Meconium Plug Syndrome, Small Left Colon Syndrome and Meconium Disease, in absence of CF and HD, concluding that these conditions were essentially the same entity with a different degree of severity. All were characterized by a combination of highly viscid meconium and poor intestinal motility, low grade obstruction, benign systemic and abdominal examination, distended loops without air fluid levels. Added risk factors are severe prematurity and low birth weight, Caesarean delivery, maternal therapy with MgSO4 . MRI in the term infant is often characterized by lack of meconium passage in the first 24-48 hours responding to a simple conservative treatment based on rectal stimulation and irrigation . In our series, all infants ≥1500 g BW were seen within the fist week of life and responded to conservative management and Gastrografin enema in 90% of the cases. Unlike their mature counterpart, LBW babies presented first clinical sign usually around the second week of life, although the condition can present at any time after birth . These infants, who often passed some smears of meconium, have a typically progressive abdominal distension with palpable bowel loops and no sign of peritonitis. Plain abdominal film shows distended small bowel loops without air fluid levels or pneumatosis. These findings are enough to make diagnosis and exclude other forms of intestinal obstruction, mainly NEC. Testing for Cystic Fibrosis may not be indicated. Once the obstruction occurred, the risk of perforation becomes higher and is estimated around 30%. Conservative management can be successfully applied in two thirds . Nevertheless, diagnosis and proper management of MRI among LBW continue to be delayed and many infants are referred already perforated as occurred in 65% of our OB, seen by the surgeon some days after obstructive symptoms appeared. This rarely occurred among IB (12,5%). Place of birth was one of the secondary factors affecting survival in our series; mortality remains strongly related to GA, BW and complicated pregnancy.
No definitive management of MRI has been stated until now, mainly for LBW cases . Since Noblett introduced Gastrografin enemas to treat meconium ileus , this became the mainly accepted conservative treatment even for MRI [1, 3, 7, 8] despite its efficacy is not yet universally recognised . Success rate is estimated around 80% and is strictly time dependent; failure is reported among cases after 14 days from diagnosis . Recently Iopamidol has been preferred to Gastrografin by some Authors  for its lower osmotic pressure, with the same rate of success. In a recent multi institutional review  a decreasing use of softening enema for MRI has been documented along the last decade. An earlier surgical approach is preferred to enema especially when it requires multiple attempts. The reason for this change may lie in the introduction of new osmotic agents, less effective of Gastrografin, or in the reluctance of Radiologist to repeat enema in most critical cases. In our series lox BW and GA were associated to a most frequent recourse to surgery. This certainly can be explained by the higher rate of bowel perforations at referral among our LBW infants but it could be also attributed to a propensity to refrain from using repeated cleansing enema in most fragile cases, especially when late referred.
Where enema has to be performed, especially when dealing with fragile LBW infants, is still matter for discussion [4, 5]. Transport to Radiology suite is sometimes difficult to arrange for artificially ventilated patients and fluoroscopy guidance is not possible in the Neonatal ICU [3, 8]. Fluoroscopy is essential to document contrast medium passing ileocecal valve and mixing with intestinal content, to get an effective clinical result. An alternative could be to perform the enema in Operating Room, when available, which offers the advantage to face promptly perforative complications  This method must be preferred in most critical patients who did not respond to bedside enema. Warming of radiology suite and proper assistance to these neonates must be guaranteed during all the procedure when not done in the Operating Room. Surgery was decided on elective basis in 11 cases, after unsuccessful enema, and on emergency basis in 12 for an overt perforation.
Instillation of N-Acetylcysteine via nasogastric tube has been reported to decreases stool viscosity by 99% in 6 hrs in early diagnosed cases  but was never attempted among our patients. Recourse to surgery is frequently reserved to late referred cases that present a perforation rate of 28% . Whenever MRI leads to intestinal perforation prompt abdominal exploration is mandatory. Percutaneous drain in extremely premature infants has been suggested but its real role has not yet been established . Elective surgical options for MRI vary from enterotomy, irrigation and primary closure to temporary stoma. Although this technique in commonly used in full term infants, irrigation may be dangerous in LBW infants and iatrogenic bowel injury during this manoeuvre has been reported . When necrotic bowel is present, minimal resection and enterostomy is recommended.