Infants suspected of pyloric stenosis usually present with the onset of non-bilious vomiting, beginning at 3-6 weeks of age. The pattern of vomiting varies, but often progresses to the characteristic ‘projectile’ vomiting. Often, infants have undergone numerous formula changes before the diagnosis is made. Severe or neglected cases can result in significant weight loss and failure to thrive.
An examiner may observe gastric peristaltic waves traveling from the infant’s left upper abdomen toward the right side and the diagnostic finding is a mobile, ovoid mass, commonly referred to as an ‘olive’, palpable in the epigastrium or the right upper quadrant. In the absence of a palpable “olive”, diagnostic imaging can be helpful. Plain radiographs of the abdomen may show gastric distention. An abdominal ultrasound is the most sensitive test for diagnosis and should be performed if the “olive” is not palpable. The characteristic appearance of pyloric stenosis on ultrasound is that of a “doughnut” or “bulls eye” on cross section of the pyloric channel. Pyloric dimensions with positive predictive value greater than 90% are muscle thickness greater than 4mm and a pyloric channel length greater than 17mm. These limits may be lower in infants less than 30 days of age(8). When ultrasound is not available, a contrast upper gastrointestinal study (UGI) will confirm the diagnosis. The classic radiographic signs are the “string sign” and the “shoulder sign” caused by the hypertrophied muscle protruding into the gastric channel.
Infants with a diagnosis of pyloric stenosis will show characteristically low Cl- and H+ ions as measured in the serum. Due to the loss of K+ and H+ ions in the urine and Cl- in the emesis, the infants will retain HCO3- and a resultant metabolic alkalosis occurs. In severe cases with diagnostic delay, hypoglycemia and hypoalbuminemia can be observed.
Infants with electrolyte abnormalities or dehydration require correction of both. Due to the severity of the dehydration, these infants are typically resuscitated with twice the maintenance volume of normal saline solution until they void. Then, potassium is added to the intravenous fluids, which are changed to half-normal saline at 1.5 times maintenance. It may take 48 hours or longer to fully resuscitate an infant and prepare them for surgery. Lactated Ringers Solution is not to be used as an initial resuscitation fluid. Nasogastric tubes should be avoided as they further deplete electrolytes.
Surgical Treatment of Pyloric Stenosis
Indications for Surgery
Since Ramstedt, the treatment has been pyloromyotomy. This procedure is done under general anesthesia with several incisions described, none of which have any particular advantage. A circumumbilcal incision is recommended by some to hide the incision. Regardless, the pyloric “tumor” is withdrawn from the wound with gentle traction and a sero-muscular incision is made from the gastric antrum to the junction of the pylorus and the duodenum. This incision is “split” with the back of a knife handle until the two halves of the pyloric ring are separate from each other and move independently.
Laparoscopic Treatment of Pyloric Stenosis
Alain, et al, reported their initial experience in 10 patients in 1991(9). In the first 2 infants the effectiveness of the laparoscopic procedure was in fact confirmed by an open abdominal incision without exteriorizing the pylorus itself. All of the patients had an uncomplicated postoperative course, and so the authors were the first to conclude that laparoscopic pyloromyotomy was a sound and technically simple procedure. Tan and Najmaldin reported their initial experience in 1993(10) . They improved on Alain’s technique in that they were able to perform the procedure with 1 assistant rather than 2, and their patients were discharged sooner than those in the earlier series. Two years later the same authors reported a series of 37 patients, all of whom underwent laparoscopic pyloromyotomy. They documented the average time of operation (29 minutes), the average time before the initiation of feedings (5.2 hours), and the average time to discharge (28 hours)(11). Furthermore they had no technical failures. In 1995 Castañón, et al, described the pyloric traumamyoplasty, an entirely new approach to splitting the hypertrophied pylorus(12). In this technique 2 crushing applications of a laparoscopic Babcock clamp were used to rupture the pyloric muscle, thus creating 2 grooves in the muscle and relieving the obstruction.
The laparoscopic pyloromyotomy is performed using a peri-umbilical telescope and two stab wounds, one for a grasper and the other for the retractable blade and the pyloric spreader. The surgeon has the choice os whether to grasp the duodenum and incise from duodenum toward the stomach, or to grasp the stomach and incise from the stomach toward the duodenum. Either way, the pyloric muscle is spread and the adequacy of the operation verified as is described above for the open procedure.
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- Grant GA, McAleer JJA: Incidence of infantile hypertrophic pyloric stenosis (letter). Lancet 1:1177, 1984
- Klein A, Cremin BJ: Racial significance in pyloric stenosis. S Afr Med J 44:1130-1134, 1970
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- Rothenberg SS: Laparoscopic pyloromyotomy: the slice and pull technique. Pediatric Endosurgery and Innovative Techniques. 1:39-41, 1997
- Pollack WF, Norris WJ: Surgical History. Dr. Conrad Ramstedt and pyloromyotomy. Surgery 42:966-970, 1957
- Tan KC, Bianchi A: Circumumbilical incision for pyloromyotomy. British Journal of Surgery 73:399, 1986
- Lamki N, Athey PA, Round ME, et al: Hypertrophic pyloric stenosis in the neonate ‘ diagnostic criteria revisited. Can Assoc Radiol J 44:21-24, 1993
- Alain JL, Grousseau D, Terrier G: Extramucosal pyloromyotomy by laparoscopy. Journal of Pediatric Surgery 26:1191-1192, 1991
- Tan HL, Najmaldin A: Laparoscopic pyloromyotomy for infantile hypertrophic pyloric stenosis. Pediatric Surgery International 8:376-378, 1993
- Najmaldin A, Tan HL: Early experience with laparoscopic pyloromyotomy for infantile hypertrophic pyloric stenosis. Journal of Pediatric Surgery 30:37-38, 1995
- Castañón J, Portilla E, Rodríguez E, et al: A new technique for laparoscopic repair of hypertrophic pyloric stenosis. Journal of Pediatric Surgery 30:1294-1296, 1995
- Bufo AJ, Merry C, Shah R, et al: Laparoscopic pyloromyotomy: a safer technique. Pediatric Surgery International 13:240-242, 1998.
- Harris SE, Cywes R: Laparoscopic pyloromyotomy. Pediatric Endosurgery and Innovative Techniques 5:405-410, 2001 15.
- Lobe TE: Laparoscopic surgery in children. Current Problems in Surgery 35:859-948, 1998
- Scorpio RJ, Tan HL, Hutson JM: Pyloromyotomy: comparison between laparoscopic and open surgical techniques. Journal of Laparoendoscopic Surgery 5:81-84, 1995
This guideline was prepared by the IPEG Guidelines Committee and was reviewed and approved by the Executive Committee of the International Pediatric Endosurgery Group (IPEG) November, 2002.
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