Minimally invasive surgery (MIS) in abdomen and thorax has been widely accepted for pediatric diseases. Thoracoscopic surgery has the advantage of less pain, better cosmetic outcomes and less musculoskeletal sequelae in comparison to open surgery. We would like to share our initial experience with thoracoscopic surgery performed by one pediatric surgeon.

We performed a retrospective review of patients who underwent thoracoscopic surgery by one pediatric surgeon between April 2010 and August 2017 in Department of Pediatric Surgery, Seoul National University Children's Hospital.

There were totally 18 cases; 8 cases for esophageal atresia, 3 cases for congenital diaphragm hernia, 2 cases for diaphragm eventration, 2 cases for esophageal duplication cyst, 2 cases for pleural mass and 1 case for esophageal bronchus. At the operation, median age was 9.5 months (range, 0-259 months) and median body weight was 9.4 kg (range, 1.9-49.4 kg). Median operative time was 157.5 minutes (range, 45-335 minutes). There was no case of open conversion and 2 cases of minor leakage at anastomosis site in case of esophageal atresia. Median follow-up month was 5 months (range, 0-87 months). During follow-up, 4 cases of esophageal atresia showed anastomosis site narrowing and average 2.5 times (range, 1-5 times) of esophageal balloon dilatation was done.

We performed thoracoscopic surgery in case of esophageal, diaphragm disease and pleural mass. Thoracoscopic surgery can be an effective and feasible option of treatment for well-selected pediatric patients of intra-thoracic disease including esophagus, diaphragm and mediastinum disease.

Purpose
Thoracoscopic repair of congenital diaphragmatic hernia (CDH) is technically challenging and requires various surgical strategies. However, studies investigating the learning curve of thoracoscopic repair of CDH are rare. The
objective
of this study was to determine whether there is a learning curve of thoracoscopic repair of CDH and analyze its pattern by cumulative sum (CUSUM) analysis.
Methods
From 2008, when the first case was performed, to 2020, children diagnosed with Bochdalek-type CDH who underwent thoracoscopic repair were included. Learning curves of 2 operators were analyzed individually using the CUSUM method which is the running total of differences between operation time of each case and the mean operation time. We divided the CUSUM curve into three phases based on its slope and performed interphase analysis of patients’ baseline characteristics and surgical outcomes.
Results
A total of 111 children (operator A, n=88; operator B, n=23) underwent thoracoscopic repair of CDH during the study period. CUSUM curve of operator A showed an ascending curve from the first case to the 33rd case, then a plateau between the 34th case and the 55th case, and a descending form from the 56th case. In interphase comparisons of surgical outcome of operator A, recurrence rate and rate of complication did not show statistically significant differences. The learning curve of operator B showed a flat overall appearance and plateaued after the 14th case.
Conclusion
Surgical experience based on 33 cases was needed to reach the learning curve to perform thoracoscopic repair of CDH. For a new surgeon experienced with assisting a skilled operator, a relatively high proficiency was obtained from the start with a shorter learning curve. Interphase analysis of surgical outcome suggests that thoracoscopic repair of CDH can be performed without compromising patients’ safety even before reaching the learning curve.