Learning curves for pediatric laparoscopy: how many operations are enough? The Amsterdam experience with laparoscopic pyloromyotomy

M. W. N. Oomen 0 L. T. Hoekstra 0 R. Bakx 0 H. A. Heij 0 0 M. W. N. Oomen (&) L. T. Hoekstra R. Bakx H. A. Heij Department of Pediatric Surgery, Emma Children's Hospital, Academic Medical Center , Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands Background Few studies on the surgical outcomes of open (OP) versus laparoscopic pyloromyotomy (LP) in the treatment of hypertrophic pyloric stenosis have been published. The question arises as to how many laparoscopic procedures are required for a surgeon to pass the learning curve and which technique is best in terms of postoperative complications. This study aimed to evaluate and quantify the learning curve for the laparoscopic technique at the authors' center. A second goal of this study was to evaluate the pre- and postoperative data of OP versus LP for infantile hypertrophic pyloric stenosis. Methods A retrospective analysis was performed for 229 patients with infantile hypertrophic pyloric stenosis. Between January 2002 and September 2008, 158 infants underwent OP and 71 infants had LP. Results The median operating time between the OP (33 min) and LP (40 min) groups was significantly different. The median hospital stay after surgery was 3 days for the OP patients and 2 days for the LP patients (p = 0.002). The postoperative complication rates were not significantly different between the OP (21.5%) and LP (21.1%) groups (p = 0.947). Complications were experienced by 31.5% of the first 35 LP patients. This rate decreased to 11.4% during the next 35 LP procedures (p = 0.041). Two perforations and three conversions occurred in the first LP group, compared with one perforation in the second LP group. - A common cause of vomiting after feeding in the first few weeks of life is infantile hypertrophic pyloric stenosis (HPS). This disorder is characterized by hypertrophy and hyperplasia of the circular muscle layer of the pylorus, with stenosis of the pylorus channel causing gastric outlet obstruction, gastric distension, and retrograde peristalsis in the stomach, which can be seen by physical examination after feeding. As a consequence, dehydration and hypochloremic metabolic alkalosis will occur. No clear pathophysiologic sequence or etiology for HPS has been described, although a relation seems to exist between maternal Bendectin use in the first trimester and infantile hypertrophic pyloric stenosis. The incidence of HPS is approximately 13 per 1,000 live births [1]. More often seen in boys, HPS occurs with a male-to-female ratio of 4:1 [2]. The surgical treatment of choice for HPS in the past century was the technique described in 1912 by Ramstedt [3], who introduced the longitudinal splitting of the seromuscular layer of the pylorus without suturing, termed pyloromyotomy. This procedure relieves the constriction and allows normal passage of stomach contents into the duodenum. The operation traditionally has been performed through a classical right upper quadrant transverse incision. Although effective at providing excellent exposure of the pylorus, this method results in an abdominal scar that grows with the patient, often becoming quite significant with time. Several other approaches currently are advocated for pyloromyotomy. In 1986, Tan and Bianchi [4] described a new technique of performing pyloromyotomy through a supraumbilical skinfold incision. This approach achieves an excellent cosmetic outcome with an apparently unscarred abdomen. In 1991, Alain et al. [5] introduced the laparoscopic approach. Since then, a few centers have reported their outcomes for open pyloromyotomy (OP) compared with laparoscopic pyloromyotomy (LP) [611]. The potential advantages of LP have included a shorter hospital stay, improved cosmesis, a shorter postoperative recovery, and less postoperative pain. The question arises whether LP is a better operation technique for HPS and therefore superior to OP. Two prospective, randomized controlled trials have compared LP and OP groups undergoing hypertrophic pyloric stenosis [12, 13]. Leclair et al. [12] showed that LP has a complication rate similar to that for the open umbilical approach but may expose patients to a risk of inadequate pyloromyotomy. However, the study of St Peter et al. [13] reported the benefits of LP as less postoperative pain, reduced postoperative emesis, and fewer complications. No difference in operating time between OP and LP was observed. However, this finding is not supported by Leclair et al. [12], who showed that the operation time was longer in the laparoscopic group. Overall, the conclusions with regard to the superiority of the laparoscopic procedure are contradictory. Another issue with regard to LP is the existence of a learning curve. As known from many laparoscopic procedures such as colonic resection, quite a number of procedures are required before the technique is safely performed. Kramer et al. [14] showed a decrease in operating time with children who underwent laparoscopic extramucosal pyloromyotomy for hypertrophic pyloric stenosis and found a positive learning curve. The first operations required an average operation time of more than 30 min. After some years of experience with the laparoscopic approach, the operations lasted an average of 16 min. Another study also showed a steep learning curve in laparoscopic operations, with a decrease in operating time after about 30 cases [15]. This study aimed to evaluate and quantify the learning curve for the laparoscopic technique at our center. A second goal of this study was to evaluate the pre- and postoperative data for OP versus LP for infantile hypertrophic pyloric stenosis. Patients and methods A retrospective study of 229 patients (196 boys and 33 girls) with infantile hypertrophic pyloric stenosis was performed. From January 2002 to September 2008, these patients underwent surgery at the Academic Medical Center and the Vrije Universiteit Medical Center in Amsterdam, the Netherlands. Of these infants, 158 (69%) underwent a standard OP via a circumbilical incision [4], and 71 (31%) had LP. The LP was introduced by one surgeon (M.O.) who had been trained during residency in another clinic. Half of the procedures were performed by this single surgeon. A total of four different surgeons performed the remaining 35 procedures, the large majority of which were supervised by the initiating surgeon. Parents were informed about the different types of procedures and offered LP for their child if they desired this approach. It was explained that LP was a relatively new technique with unproven advantages over OP. The parents were allowed to choose the type of operation performed. Preoperative parameters including sex, age at admission, and age at operation were collected from all the parents. The peri- and postoperative data studied in both groups were operating time, hospital stay, the number and nature of complications, and the consequences of these complications. Furthermore, the number of conversion (...truncated)