If EMP has not evolved over time, the surgical access has changed substantially. The initial open approach was a midline laparotomy, which has moved toward a transverse laparotomy and then a smaller transrectal (from the rectus abdominis) approach in the right upper quadrant. A first major change toward minimal invasive surgery was suggested by Bianchi, with a circumumbilical approach, which rapidly spreads among pediatric surgeons [65]. Tan and Bianchi described in 1986 a semicircular supraumbilical skinfold incision leaving an almost invisible scar. Through this minimal incision, the pylorus is palpated, seized with a Babcock clamp, and delivered through the umbilicus to perform the EMP out of the abdomen. Somehow it can be difficult to bring out a big firm pylorus. Then the aponeurotic fascia must be open longitudinally on the midline as far as needed, to allow easy extraction. Once the EMP is done, the fascia is sutured. The transumbilical incision for EMP allows excellent access to the pylorus, while leaving an almost undetectable scar.

Modifications of the Bianchi’s umbilical approach were suggested by some authors. As there are some obvious technical difficulties in delivering a large pyloric tumor through the umbilicus even after opening the midline fascia, instead of bringing the pylorus out through the umbilicus with subsequent traction, the pylorus is kept in situ and the EMP is performed intracorporeally [66–69]. To stabilize the pylorus and draw it up just under the umbilical wound, suspension threads are placed in the hypertrophic muscle [67, 69].

One of the first laparoscopic procedures even done in children were pyloromyotomies performed by Dominique Grousseau and Jean-Luc Alain from Limoges, France, in 1989, and published first in French in 1990 [70] then in English with ten cases in 1991 [71]. The technique was long to gain popularity but by some pediatric surgeons involved in pediatric minimal invasive surgery.

Initially three ports were used: a 5 mm in the umbilicus for the telescope, using the Hasson’s open technique, and two 3 mm for instruments, one on the midline, the second on the right midclavicular line just below the liver. The pylorus was caught in a Babcock grasper. The pyloric serosa was opened longitudinally on its anterior face using a 3-mm retractable knife. Then the pyloric muscle was split with a laparoscopic pyloric spreader.

The laparoscopic EMP has evolved toward simpler technique. Nowadays, only one 5-mm port is placed in the umbilicus and none for the instruments. As the left hand is used only to seize the pylorus, the instrument is left in place from beginning to end and do not require a port. As it appeared difficult to grab the big firm pylorus with a small Babcock grasper, today we use a smooth Johann grasper placed transversally on the duodenum just below the pyloroduodenal junction. This allows to lift up or to rotate the pylorus with a good exposure of the pyloroduodenal junction. A small 2–3-mm disposable knife (designed for ophthalmology or for arthrotomies) is inserted through the skin on the midline just in front of the pylorus. The blade is not pushed down to the pylorus, but the pylorus is lifted up toward the blade. Then the wound site is used to insert a smooth 2 or 3-mm grasper (Johann, Maryland) to split the muscle. The use of one of the specially designed pyloric spreaders is helpful but not mandatory.

There are no contraindications to laparoscopic IHPS. However, prematures bear a risk of cerebral bleeding due to the elevation of pressure in the superior vena cava related to insufflation, even done at a low pressure (5–6 mmHg). Children with cardiac defect shunting from left to right could embolize in their brain and therefore should be recused for laparoscopy as those with lung anomalies (Figs. 14.2 and 14.3).

We have had to wait for more than a decade until data were available to compare open with laparoscopic EMP (lap).

The French team of Nantes has performed a randomized prospective study of respectively 50 EMPs done by laparoscopy with 52 open. The durations of surgery and anesthesia were longer in the lap group. There was no difference in the incidence of postoperative vomiting, and the complications were similar (1 perforation each ie 1 %; 2 wound complications open versus 1 lap ie 3 %; 3 incomplete myotomies after lap ie 3 %) but significantly with less pain in the lap group (p < .0001) [72].

A multicenter international double-blind controlled trial across six tertiary pediatric surgical centers has been published with 180 infants randomly assigned to open (n = 93) or laparoscopic EMP (n = 87) [73]. Complications were similar (17 vs 15). All perforations (1 vs 2) and the 3 incomplete myotomies by laparoscopy were done by nontrainees. Full oral feeding was achieved faster in the lap group (p = .002); there were less pain in the lap group (p = .011); and the postoperative hospital stay was shorter in the lap group (p = .027). The postoperative vomiting and complications were similar. The parental satisfaction was higher for the lap group (p = 0.011). The design of the study was to recruit 200 infants (100 per group). However, the data monitoring and ethics committee recommended halting the trial before full recruitment because of significant treatment benefit in the laparoscopy group at interim analysis. Their conclusions were: “Both open and laparoscopic pyloromyotomy are safe procedures for the management of pyloric stenosis. However, laparoscopy has advantages over open pyloromyotomy, and we recommend its use in centers with suitable laparoscopic experience.”

Keith Georgeson and his team from Birmingham, AL, have compared the incidence and type of technical complications seen in a retrospective series of pyloromyotomies done by open (225) and by laparoscopic (232) EMP in similar groups performed by multiple surgeons. The overall incidences of complications were similar in the two groups (open 4.4 %; lap 5.6 %). There was a greater rate of perforation with the open technique (3.6 % vs 0.4 %) and a higher rate of postoperative problems including incomplete myotomy in the laparoscopic group (0 vs 2.2 %). They conclude that: “This lower rate of perforation could be attributed to improved visualization because of the magnification provided by laparoscopy. Alternatively, the lower perforation rate could be owing to a less “aggressive” pyloromyotomy” [74].

Sola published a meta-analysis upon six prospective studies of level 1 (5) or 2 (1) in which it appeared that laparoscopic EMP had a lower total complication rate (p = .04) due to a lower wound complication rate (p = .03). The laparoscopic EMP had shorter time to full feedings (p < .00001) and shorter postoperative hospital stay (p = .0005) with no statistically significant differences in mucosal perforation (0.9 % vs 1.3 %), wound infections, and postoperative vomiting. There were six incomplete myotomies (4 lap vs 2 open). The conclusion was: “This systematic review and meta-analysis favors the laparoscopic approach with significantly reduced rate of total complications, which is mostly due to a lower wound complication rate” [75].

Finally, Carrington and the British team from Great Ormond Street Hospital for children, London, have compared the costs of the laparoscopic EMP with the open approach in a multicenter randomized double-blind controlled trial, for which the primary outcomes were time to full feeds and time to discharge. Operation costs were similar between the two groups. A shorter time to full feeds and shorter hospital stay in lap versus open patients resulted in a highly significant difference in ward costs ($ 2,650 ± 126 lap versus $ 3,398 ± 126 open; p = .001) and a small difference in other costs. Overall, laparoscopic patients were $ 1,263 less expensive to treat than open patients [76].

To summarize, the quoted advantages of laparoscopic pyloromyotomy compared to the open approach are reduced postoperative pain, shorter hospital stay, earlier return to normal activity, and cosmetic benefits [77, 78].

Postanesthetic apnea in the premature <60 WGA is well known and specific recommendations have been made to prevent them. However, postanesthetic apnea can occur in full-term babies without perinatal problem after some surgical procedures including cures of IHPS [79]. Some recommendations have been made but a strict postoperative monitoring and supervision in a specialized environment is wise [80, 81].

The nasogastric tube is suctioned at the end of the procedure before its removal, except in case of sutured perforation. Wounds are infiltrated with 0.25 % bupivacaine 2 mg/kg for postoperative pain relief. Antibiotics are given only in case of mucosal tear. Oral feeding may be resumed on return to the ward and increased as tolerated.

Isolated vomiting can endure for a few hours/days (≤2 days) after surgery in 10–15 % of cases. They are related to the gastric irritation associated with preoperative vomiting and to the traction on the pylorus during the procedure [82]. Subsequently, they are less frequent after laparoscopic or transumbilical intracorporeal EMP than after exteriorized one. However, they must not be minimized as they can reveal a perforation.

The more electrolyte abnormalities children have at the time of diagnosis, the longer they stay in the hospital [64].

Complications are between 1 and 3 % in the hands of pediatric surgeons and mostly related to incomplete myotomies or perforations [72, 82]. Infections of the umbilical wounds have been described (1–7 %). However, with the increment of laparoscopy in neonates and infants, pediatric surgeons have learned how to clean the umbilicus, and the rate of umbilical infections is decreasing.

Complications per surgeon drop with experience. This has been evidenced in laparoscopic EMP. Mucosal perforation was experienced by 8.3 % of the patients in the initial series, as compared with 0.7 % in the later series reported by Van der Bilt [78]. Insufficient pyloromyotomy occurred in 8.3 % of the initial series, as compared with 2.7 % of the later series. He suggested that the learning curve could be 15 laparoscopic IHPS [78] (Fig. 14.4).

Before the era of the EMP and until the years 1960s, IHPS were treated conservatively using atropine or equivalents (belladonna, atropine methylnitrate (eumydrin)). Although pyloromyotomy became the first choice of treatment in Western countries, several authors, mostly from Asian countries (Japan [83–86], Taiwan [87], and India [88]) but also from Germany [89], have revisited the nonsurgical treatment using intravenous or oral atropine for IHPS. Atropine sulfate is given daily for 1–8 days at various regimens [89] with increasing doses until vomiting stopped then maintained for 2 weeks. The rationale for atropine therapy is that the physiopathology of IHPS may be partially due to impaired function of acetylcholine and muscarinic receptors, thus releasing the pyloric muscle. Medical treatment may require 7 days or more of skilled nursing and careful follow-up. The results are fairly good with no significant complications. About 10–25 % patients require surgery for failure of medical treatment.

Conservative medical treatment with atropine is an option. To date there are no randomized controlled studies answering the question whether therapy with atropine can achieve sufficient resolution of IHPS to avoid surgery but only case series and a retrospective cohort study with low level of evidence [90]. Mercer studied ten relevant articles on the use of atropine for IHPS. The success rate of atropine therapy is about 85 %, whereas surgical EMP is >95 % [90]. Under a humoristic editorial title (“Medical Treatment of Idiopathic Hypertrophic Pyloric Stenosis: Should We Marinate or Slice the “Olive”?”), Rudolph, a pediatric gastroenterologist, advocates for the surgery arguing it solves the problem within 48–72 h with less than 1 % complications for a lower cost [91]. As per Aspelund, we believe conservative medical treatment with atropine should be considered as an alternative in infants with contraindications to anesthesia or surgery [92].

In infants, gastric outlet obstruction (GOO) is most often due to IHPS. However, several conditions other than IHPS may cause non-bilious vomiting in infants and children that we must be aware of (Table 14.1).

Gastric polyps may be either hyperplastic or adenomatous. Hyperplastic polyps are most common in children and account for 70–90 % of benign gastric polyps. A study at Johns Hopkins University reported that the prevalence of duodenal polyps in children was 0.4 % (22 of 5,766) of upper gastrointestinal endoscopies. Most of the duodenal polyps in that series were syndromic and were commonly associated with familial adenomatous polyposis [63, 94, 96]. However, sporadic cases have been described before or inside the pylorus [93].

An ectopic pancreas is not uncommon in children and the pyloric location has been described. Besides GOO, they can cause epigastric pain [101] and develop gastrointestinal bleedings or late malignant transformation. Thus surgical removal is suggested [100].

Even very unusual in infants, antral or pyloric malignancies have been reported and should always be considered as a possible etiology of a pyloric obstructive mass in older children [97, 105, 107]. The literature concerning such gastropyloric tumors in children is mainly limited to case studies. Gastrointestinal stromal tumor (GIST) [106], Burkitt’s lymphoma, gastroblastoma [103], adenomyoma [104], and plasma cell granuloma [97] have been reported.

Prepyloric webs are unusual mucosal partial or total diaphragms that may cause GOO. Histologically, the web consists in normal mucosa and submucosa. It appears in the early infancy in most cases, but it has been reported in older children and even in adults. The treatments are either endoscopic or surgical resection [110–113].

Acute gastric volvulus in newborns and infants is known as a rare but life-threatening emergency that requires prompt recognition and treatment. The first description of this condition was made in 1866 by Berti based on the autopsy of a 61-year-old woman. Oltmann described the first pediatric patient in 1899. To date, more than 250 gastric volvulus in children have been described [116]. Gastric volvulus can be defined as torsion of more than 180° of the stomach around itself thus occluding the pylorus and inducing intermittent or persistent vomiting. The diagnosis is done by upper gastrointestinal contrast studies. The radiological signs include horizontalness of the stomach, the greater curvature being above the lesser one and crossing in front of the lower esophagus with the pylorus looking downward. Once recognized the surgical procedure is an anterior gastropexy with reinforcement of the esophagogastric angle performed by laparoscopy, without antireflux-associated procedure [116].

In the acquired conditions, children are older than the former one, i.e., after 1 year of age. Albeit unusual, peptic ulcers can occur in children and according to their sites may occlude the pylorus. Prior to proton pump inhibitors (PPI) and H2 blockers, peptic ulcer disease secondary to Helicobacter pylori was a more common cause of GOO than today. Helicobacter pylori are evidenced by urease test and medically treated. However, even at the era of PPI, persistent ulcer under adequate treatment can require for surgery [117].

The ingestion of foreign bodies is a common problem in infants, but fortunately the majority of them will pass through the digestive tract without any adverse effects. The peak incidence of foreign body ingestion is between 6 months and 3 years and coins are the most common. It has even been described in neonates (esophageal zipper in a 2 months old baby) [121, see also Chap. 16]. Most ingested foreign bodies remain entrapped in the esophagus at the level of its anatomic narrowing. However, some of them can be trapped in the antrum occluding the pylorus. There are no guidelines available to determine which type of object will pass safely. The size depends on the age of the child. The eventuality of foreign body impaction must always be considered in infants below 5 years of age and searched for.