Intussusception is the invagination of one part of the intestine (the intussusceptum) into another adjacent distal segment (the intussuscipiens). It is one of the most frequent causes of acute bowel obstruction in infants and toddlers. As the first-line management for intussusception, non-surgical reduction, with barium, saline, or air, has high successful rate[5, 6]. According to the literature, the success reduction rate varies in different institutions, from 80% to 95%. During the study period, a total of 34 patients who underwent laparoscopic reduction of intussusception performed by a senior attending surgeon were recruited. In line with the literature, ileocolic intussusception is the most common anatomic type, which constituted the majority in our study, accounting for 76.5 %, followed by jejunojejunal and ileoileal (17.6%). The air enema reduction rate at our institution is 89% (278/312), which is identical to the literature. Surgical intervention is reserved for all patients, in which the intussusception was irreducible by enema techniques. Recently, laparoscopic reduction is demonstrated to be a safe and feasible approach and has been gradually recognized as the alternative to the open approach[3, 5, 9, 10]. However, all laparoscopic surgery would be confronted with conversion. The conversion rate from laparoscopic management to open procedure were extremely variable, ranging from 0% to 79%. With a majority of the studies included the umbilical extension patients in the laparoscopic group, the overall conversion rate for the combined studies fell to 17%[2, 11]. The overall conversion rate of our study was even lower (14.7%) (5/34).
With the tremendous advancement of laparoscopic techniques in children in the recent years, its use in the management of intussusception become widely adopted. The question of how many procedures are needed to overcome the initial learning period becomes imperative. To date, there is still no reports of the learning curve for laparoscopic reduction of pediatric intussusception.
In our series, we reviewed our experience with laparoscopy in patients with radiologic irreducible intussusception and evaluated the learning curve associated with this procedure by comparing the complication rate between the first and the second groups. Obviously, the complication rate of the second group was far less than first group. Therefore, the first 15 patients might reflect the learning curve, with a dramatically declined in complications for the last 19 patients. This implied that the learning curve for laparoscopic reduction of intussusception in our research was 15 cases. Inconsistent with the complication rate, the operative time and postoperative length of hospital stay in the second group is obviously not shorter than the first group, in spite of the differences were not statistic significant. This contradiction might result from the imbalanced distribution of pathologic lead points in the two groups (p = 0.024). Of the 34 patients, 6 had a pathologic lead point, all in the second group and bowel resection and anastomosis were carried out by slightly extending the umbilical trocar incision in the midline and exteriorizing the lesion. No doubt these complex procedures added to the operative time. Likewise, children who underwent intestinal anastomosis had longer postoperative hospital stays than those who did not, as their time to tolerate full oral feeding is longer.
Although operative time may be easily measured and compared, it may not be the most proper endpoint of the learning curve. In a laparoscopic procedure with formalized surgical approach, operative duration was most affected by the experience of the surgeon and can also vary with first assistant level, operating room nurses, anesthetists, and medical devices[13, 14]. In our present study, except for the first assistants were several different residents, the other factors were constant. If there is no standard surgical approach, operative time might be the most complicated parameter since it involves each step of the procedure during the incision to dressing time. Additional procedures, such as appendectomy, lymph node biopsy, can prolong total operative time and may increase complication rate too. Since appendectomy does not seem to reduce the recurrence rate of intussusception, appendectomy was performed only if the appendix becomes inflamed or ischemia[2, 15]. Lymph node biopsy was performed when there was suspicion of lymphoma. Given the above, a standard laparoscopic approach to achieve reduction of pediatric intussusception was difficult to attain, as other researchers found out. Hence, there was potential inherent bias as this was a heterogenous group of patients with lacking in standardized operative approach for children needing surgery for intussusception. Therefore, we did not take operative time as an endpoint to evaluate learning curve of laparoscopic reduction of intussusception.
However, our outcomes should be elucidated with caution, as there are several limitations in our study. One limitation relates to its retrospective design with lacking a standard protocol for data collection, which may impact data quality. Accordingly, we only involved the patients from the latest six years, as the patients' information are most complete and reliable. Fortunately, there is no patient loss to follow-up. Furthermore, retrospective studies are often limited by selection bias, whereby patients’ baseline characteristics may affect their intervention option. With regards to our study, there was no significant difference in baseline characteristics between the two groups (age, gender, ASA class, BMI, clinical manifestation, preoperative air enema attempts, anatomic types of intussusception, length of intussusception, recurrence of intussusception, No. of intussusception, concomitant procedure). Thirdly, subject to the pediatric population and relatively high success rate of air enema, the demands for surgery have plummeted, which led to a limited sample size of our study and thus may generate type II error and affect the overall results. Additionally, there is potential recall bias with neglected minor complications, as we only documented the complications considered to be relevant and, especially, those involving certain forms of intervention. Lastly, we only analyzed the learning curve of a single surgeon in our center, lacking the comparison with other qualified surgeons or other institutions, which requires further investigation with these factors taken into account.