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Introduction: Repairing damaged cartilage poses significant challenges, particularly in cases of congenital cartilage defects such as microtia or congenital tracheal stenosis, or as a consequence of traumatic injury, as the regenerative potential of cartilage is inherently limited. Stem cell therapy and tissue engineering offer promising approaches to overcome these limitations in cartilage healing. However, the challenge lies in the size of cartilage-containing organs, which necessitates a large quantity of cells to fill the damaged areas. Therefore, pluripotent stem cells that can proliferate indefinitely are highly desirable as a cell source. This study aims to delineate the differentiation conditions for cartilage derived from human embryonic stem cells (ESCs) and to develop an automated cell culture system to facilitate mass production for therapeutic applications. Methods: Cartilage cell sheets were derived from human ESCs (SEES2, clinical trial-compatible line) by forming embryoid bodies (EBs) with either conventional manual culture or a benchtop multi-pipetter and an automated medium exchange integrated cell incubator, using xeno-free media. Cell sheets were implanted into the subcutaneous tissue of immunodeficient NOG mice to obtain cartilage tissue. The properties of cartilage tissues were examined by histological staining and quantitative PCR analysis. Results: We have optimized an efficient xeno-free system for cartilage production with the conventional culture method and successfully transitioned to an automated system. Differentiated cartilage was histologically uniform with cartilage-specific elasticity and strength. The cartilage tissues were stained by Alcian blue, safranin O, and toluidine blue, and quantitative PCR showed an increase in differentiation markers such as ACAN, COL2A1, and Vimentin. Automation significantly enhanced the efficiency of human ESC-derived chondrocyte differentiation. The number of constituent cells within EBs and the seeding density of EBs were identified as key factors influencing chondrogenic differentiation efficiency. By automating the process of chondrogenic differentiation, we achieved scalable production of chondrocytes. Conclusions: By integrating the differentiation protocol with an automated cell culture system, there is potential to produce cartilage of sufficient size for clinical applications in humans. The resulting cartilage tissue holds promise for clinical use in repairing organs such as the trachea, joints, ears, and nose.

Autologous oral mucosa-derived epithelial cell sheet transplantation was devised as a new treatment for refractory postoperative anastomotic stenosis in patients with congenital esophageal atresia (CEA) and congenital esophageal stenosis (CES). Transplantation therapy was performed on three patients with refractory postoperative anastomotic stenosis who had undergone endoscopic balloon dilatation (EBD) at least twice in one year and at least five times in total. Epithelial cell sheets were prepared from the patients' oral mucosa and transplanted over the esophageal wounds caused by EBD using a specially developed transplantation device. After transplantation, the patients were followed for 48 weeks. Subject 1 underwent two transplantations and showed temporary improvement in stenosis, but required periodic EBD and eventually had the stenotic area removed. Subject 2 did not require EBD for more than two years post-transplantation; Subject 3, until one year after transplantation. Both Subject 2 and Subject 3 experienced improvement in the passage of food and drink and were able to consume a regular diet as opposed to a full liquid diet. These results suggest that cell sheet transplantation therapy is effective in some cases.Trial registration: UMIN, UMIN000034566, registered 19 October 2018, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000039393.

Introduction: Decellularized tissue exhibits cell matrix-like properties, along with reduced antigenicity. We explored the potential of decellularized allogeneic trachea to restore the upper respiratory tract, focusing on pediatric application. This study specifically aimed at long-term observation of tissue regeneration using a micro-miniature pig model. Methods: Artificial defects (15 × 15 mm) in the subglottis and trachea of micro-miniature pigs were repaired by transplantation of either allogeneic decellularized or fresh (control) tracheal patches. Pigs were evaluated in situ, by bronchoscopy, every three months, and sacrificed for histological examination at six and twelve months after transplantation. Results: No airway symptom was observed in any pig during the observation period. Bronchoscopy revealed the tracheal lumen to be restored by fresh grafts, showing an irregular surface with remarkable longitudinal compression; these changes were mild after restoration with decellularized grafts. Histologically, while fresh graft patches were denatured and replaced by calcified tissue, decellularized patches remained unchanged throughout the observation period. There were regeneration foci of cartilage adjacent to the grafts, and some foci joined the decellularized graft uniformly, suggesting the induction of tracheal reconstitution. Conclusion: Allogeneic decellularized tracheal tissue could serve as a promising biomaterial for tracheal restoration, especially for pediatric patients at the growing stage.

We present the case of a 4-year-old girl in whom a vitelline vessel remnant (VVR) was incidentally detected and then resected during laparoscopic inguinal hernia repair. VVR can cause intestinal obstruction, which is sometimes fatal. There are few reports of asymptomatic VVR that are discovered incidentally during surgery.Inguinal hernia repairs account for a large percentage of the operations performed by pediatric surgeons. Currently, the laparoscopic approach is most often used because of its minimal invasiveness and cosmetic results. The laparoscopic approach can also incidentally detect unknown abnormalities, such as non-symptomatic VVR, in the abdominal cavity, thereby facilitating its treatment in a minimally invasive manner. VVR may have abundant blood flow. Therefore, during laparoscopic resection, attention to bleeding is important.

In recent years, intraoperative ICG fluorescence has been used to evaluate blood flow and identify bile ducts. Moreover, varicocelectomy with intraoperative imaging using ICG has been reported; however, most of the reports have been on sparing lymphatics to prevent secondary hydrocele. Unlike conventional ICG imaging techniques, the PINPOINTⓇ system was able to display veins clearly and easily switch to color mode by simply pressing a button on the ICG at hand. In terms of simplicity, curability, and recurrence rate, the method of varicocelectomy remains controversial, such as microscopic, laparoscopic, total vascular ligation, or vein-only ligation. However, if recurrence rate is improved, considering the testicular atrophy caused by insufficient blood flow and the minimally invasive nature of the procedure, laparoscopic ligation of only the veins is ideal. We have successfully performed laparoscopic varicocelectomy by utilizing the characteristics of the PINPOINT® system and the intraoperative ICG fluorescence technique, sparing the arteries and lymphatics, and securely ligating and dissecting only the veins, including the surrounding venules. It is suggested that this technique can be used to perform pediatric laparoscopic varicocelectomy without increasing the recurrence rate compared to microscopic techniques.

Background: Total colonic aganglionosis (TCA) and long segment aganglionosis (LSA) are rare forms of Hirschsprung disease (HD). Laparoscopic resection of total or the longer segment of the colon has not been unestablished for these forms. Methods: We retrospectively reviewed five infants with TCA or LSA who underwent the blunt tip dissector (BD) assisted laparoscopic Soave pull-through procedure, and patients’ characteristics and procedure outcomes were analyzed. Results: One infant with TCA had Mowat–Wilson syndrome. Ileostomy for TCA and transanal catheter placement for LSA allowed full enteral feeding with good weight gain before operation. The BD manipulator used in the laparoscopic surgery was simple to use and powerful enough to create tension, expand operating space, and improve access to specific parts of the mesentery or pelvis. No intraoperative complications such as perforation or bleeding were noted; thus, the operation was completed uneventfully, without conversion to open surgery in all cases. All the patients had excellent cosmetic results, without late complications. Conclusions: The BD manipulator is safe and effective to facilitate laparoscopy-assisted Soave pull-through procedure in children with TCA and LSA. This approach may be applied to the other pediatric diseases, which require resection of the longer segment of the colon.

Lung abscesses are very rare in infants, and most cases are cured by antibiotic administration. However, surgical treatment was necessary in our case when deterioration was seen despite using antibiotics for 1 week. A 5-week-old male infant showed high levels of inflammatory biomarkers on laboratory tests. Computed tomography (CT) revealed a fluid-filled lesion about 34 × 28 mm with air-fluid level arising from the left upper lobe. We initiated antibiotic treatment; however, after 1 week of antibiotic treatment, a chest X-ray showed no improvement. Under ultrasound guidance, we punctured under the left scapula into the abscess space. Purulent discharge and air were aspirated, and we placed a pigtail catheter into the abscess space. The air leak continued for 2 weeks after drainage; therefore, we replaced the pigtail catheter with a straight and thinner catheter. Five days after replacement of the catheter, the air leak had stopped. Six weeks after drainage, chest X-ray and CT showed no lung abscess or pneumothorax, and he was discharged soon after. There had been no recurrence at the 3-month follow-up. In cases of lung abscesses resistant to antibiotic treatment, we should consider the option of percutaneous drainage as a minimally invasive surgical approach. (197 words).

Exostosis is one of the most common benign bone lesions. It could be a solitary lesion or multiple lesions presented as part of HME. This condition often affects the metaphyseal region of long bones, including femur, tibia, humerus and ribs. Rib exostosis may cause severe complications such as pneumothorax, hemothorax, and diaphragmatic injury. We report two patients with asymptomatic rib exostosis who underwent surgical excision to prevent severe complications. The first patient was a 13-year-old male with HME. At the eight-year follow-up, the size of the exostosis at the left ninth rib was found to have increased to 5 cm in diameter and it compressed the diaphragm. Surgical excision was performed to prevent possible complications. The second patient was a 10-year-old male with HME. At the seven-year follow-up, the size of the exostosis at the right fourth rib was found to have increased to 5 cm in diameter and it protruded into the thoracic cavity. Surgical excision was performed to prevent possible complications. Both patients recovered uneventfully. The periodic evaluation of the size and shape of rib exostosis is important in HME patients, because we must judge the proper timing for surgical excision to prevent severe complications.

Indirect inguinal hernia is one of the most common congenital abnormality in children. In approximately 15–20% of female patients, the hernia sac contains an ipsilateral ovary, but a few cases have been reported in which the uterus and both ovaries are within the hernia sac. Ultrasonography is a very effective tool to detect prolapsed organs in inguinal hernia; however, detection may be difficult in infants. The present study describes a rare case of inguinal hernia containing the uterus and both ovaries. The hernia was sliding hernia and Bevan's technique was adopted for radical herniorrhaphy. The clinical features of the disease are discussed.