Takaya Suzuki

INTRODUCTION: Lung transplantation combined with pectus excavatum repair has been reported in selected patients with severe pectus excavatum to expand the restricted thoracic cavity and facilitate graft accommodation. However, the safe implementation of this surgical strategy may be challenging in patients with extensive pleural adhesions after repeated pleurodeses, because of the increased risk of postoperative bleeding and re-thoracotomy.CASE PRESENTATION: A 15-year-old boy with interstitial lung disease, secondary pulmonary hypertension, severe pectus excavatum, and multiple prior bilateral pleurodeses underwent deceased-donor bilateral lung transplantation using a planned delayed chest closure (DCC) strategy. Preoperative CT showed marked thoracic deformity with a Haller index of 9.1 and a leftward mediastinal shift. Because extensive pleural adhesions were expected to complicate graft implantation and hemostasis and increase the risk of re-thoracotomy for postoperative bleeding, a 2-stage strategy consisting of planned DCC followed by pectus bar placement at definitive chest closure was established at the time of transplant listing in collaboration with an external pectus specialist. Bilateral lung transplantation was performed under venoarterial extracorporeal membrane oxygenation support, followed by temporary chest closure. At the second-stage operation on POD 2, 2 pectus bars were placed, and additional graft volume reduction was performed, allowing definitive chest closure without hemodynamic compromise. The patient was discharged home on POD 69 without wound complications or implant-related infections.CONCLUSIONS: This case suggests that lung transplantation may be feasible in carefully selected patients with severe pectus excavatum and extensive pleural adhesions, with appropriate multidisciplinary planning. A preplanned 2-stage strategy incorporating DCC and pectus bar placement at definitive chest closure represents a potential option for such complex cases.

INTRODUCTION: Mediastinal ectopic thyroid tissue is rare and is usually asymptomatic. Intratumoral hemorrhage causing acute mediastinal compression and cardiac arrest is extremely uncommon. We report a case of cardiac arrest caused by hemorrhage of a giant mediastinal ectopic thyroid, successfully managed with venoarterial extracorporeal membrane oxygenation (VA-ECMO) and emergency surgical decompression by tumor removal.CASE PRESENTATION: A 71-year-old woman with a long-standing anterior mediastinal tumor was transferred to our hospital because of dyspnea and shock after a fall. Contrast-enhanced CT revealed a giant anterior mediastinal tumor occupying the left hemithorax, with active extravasation and marked mediastinal deviation. Transarterial embolization was performed; however, she developed cardiac arrest shortly after embolization, presumably due to rapid tumor enlargement and severe mediastinal compression caused by intratumoral hemorrhage. Cardiopulmonary resuscitation was immediately initiated, and VA-ECMO was established. Emergency tumor removal and hemostasis were performed through a 4th-intercostal clamshell incision. The tumor occupied almost the entire left thoracic cavity and was extensively adherent to the chest wall and mediastinum, with particularly firm adhesion to the left brachiocephalic vein. The tumor was removed with combined resection of the left brachiocephalic vein. Histopathological examination revealed benign ectopic thyroid tissue without malignant findings. The postoperative course was complicated by bleeding, infection, acute kidney injury, and prolonged impaired consciousness. Postoperative hypothyroidism was identified after pathological confirmation of ectopic thyroid tissue, and levothyroxine replacement was initiated. The patient was transferred to a rehabilitation hospital on POD 72 and is currently living at home 1 year after surgery.CONCLUSIONS: Giant mediastinal ectopic thyroid tissue can cause fatal circulatory collapse when complicated by intratumoral hemorrhage. Although the patient was in a critical condition, she was successfully rescued by VA-ECMO followed by emergency decompression through surgical tumor removal.

Purpose: Single-lung transplantation (SLTx) recipients remain vulnerable to intraoperative fluid overload due to the presence of the native diseased lung. This study evaluated the impact of weight-adjusted intraoperative fluid balance on postoperative outcomes in brain-dead donor SLTx recipients.Methods: We analyzed 88 SLTx recipients categorized into low-fluid (<70 mL/kg; n = 44) and high-fluid (≥70 mL/kg; n = 44) groups based on the median (70.3 mL/kg). Multivariable logistic and linear regression analyses, with natural-log transformation of mechanical ventilation duration and ICU stay, were adjusted for operative duration, blood loss, and extracorporeal life support (ECLS) use.Results: Donor characteristics were comparable between groups. High fluid balance (≥70 mL/kg) was associated with significantly higher 48-hour primary graft dysfunction (PGD) Grade 3 rates (34.1% vs. 6.8%; P = 0.003), tracheostomy rates (36.4% vs. 9.1%; P = 0.004), longer mechanical ventilation (4 vs. 2 days; P = 0.016), and ICU stay (10 vs. 6 days; P = 0.011). Postoperative ECLS continuation at 48 hours was identical (2.3% vs. 2.3%). In multivariable analysis, high fluid balance remained significantly associated with 48-hour PGD Grade 3 (odds ratio: 4.91; P = 0.039).Conclusion: A high intraoperative fluid balance was independently associated with severe 48-hour PGD Grade 3 following SLTx, supporting careful attention to intraoperative fluid balance in these patients.

INTRODUCTION: Myelolipoma is a benign tumor composed of mature adipose tissue and hematopoietic elements that typically arises in the adrenal glands, and involvement of the anterior abdominal region is extremely uncommon. We report a rare case of myelolipoma arising in the subxiphoid preperitoneal region adjacent to the site where a sternum-lifting device had been placed during previous surgery.CASE PRESENTATION: A 62-year-old man had undergone extended thymectomy for thymoma associated with myasthenia gravis at the age of 39. The procedure was performed via bilateral video-assisted thoracoscopic surgery using a sternum-lifting technique. The tumor was classified as Masaoka stage III, and postoperative radiotherapy was administered. No recurrence was observed during 13 years of follow-up. Ten years after completion of follow-up, CT performed for an unrelated condition incidentally revealed a slowly enlarging 65 × 40-mm mass in the preperitoneal space, adjacent to the previous surgical site where a sternum-lifting device had been placed. MRI demonstrated a fat-containing component within the lesion, and the differential diagnosis included liposarcoma and teratoma. Complete surgical resection was therefore planned. A midline incision extending caudally from the xiphoid process was made, and en bloc resection of the tumor with the involved peritoneum was performed via laparotomy. Histopathological examination revealed mature adipose tissue admixed with hematopoietic elements, confirming the diagnosis of myelolipoma.CONCLUSIONS: This unique case of extra-adrenal myelolipoma highlights the importance of MRI-based qualitative assessment for tumors arising at unusual sites and underscores the need to include extra-adrenal myelolipoma in the differential diagnosis of fat-containing lesions occurring at previous surgical sites.

Lung transplantation is a critical treatment for patients with end-stage lung diseases like idiopathic pulmonary fibrosis, but challenges such as donor shortages and posttransplant complications persist. Bioengineered lungs, integrating patient-specific cells into decellularized animal scaffolds, present a promising alternative. Despite progress in using bioengineered lungs in animal models, functionality and structure remain immature. This protocol addresses a critical barrier in organ bioengineering: the need for a cost-effective experimental platform. By using mouse models instead of larger animals like rats or swine, researchers can significantly reduce the resources required for each experiment, accelerating research progress. The protocol outlines a detailed procedure for lung bioengineering using mouse heart-lung blocks and human primary cells, focusing on isolation strategy for the mouse heart-lung block, decellularization, bioreactor setup, perfusion-based organ culture, and orthotopic transplantation of bioengineered lungs. This mouse-scale platform not only reduces experimental costs but also provides a viable framework for optimizing cell types and numbers for recellularization, testing different cell types using histological and molecular methods, and ensuring blood flow post-transplantation. The method holds potential for broad applications, including studying cell interactions in three-dimensional culture conditions, cell-matrix interactions, and ex vivo cancer modeling, thereby advancing the field of organ bioengineering.

Lung transplantation is a critical treatment for patients with end-stage lung diseases like idiopathic pulmonary fibrosis, but challenges such as donor shortages and posttransplant complications persist. Bioengineered lungs, integrating patient-specific cells into decellularized animal scaffolds, present a promising alternative. Despite progress in using bioengineered lungs in animal models, functionality and structure remain immature. This protocol addresses a critical barrier in organ bioengineering: the need for a cost-effective experimental platform. By using mouse models instead of larger animals like rats or swine, researchers can significantly reduce the resources required for each experiment, accelerating research progress. The protocol outlines a detailed procedure for lung bioengineering using mouse heart-lung blocks and human primary cells, focusing on isolation strategy for the mouse heart-lung block, decellularization, bioreactor setup, perfusion-based organ culture, and orthotopic transplantation of bioengineered lungs. This mouse-scale platform not only reduces experimental costs but also provides a viable framework for optimizing cell types and numbers for recellularization, testing different cell types using histological and molecular methods, and ensuring blood flow post-transplantation. The method holds potential for broad applications, including studying cell interactions in three-dimensional culture conditions, cell-matrix interactions, and ex vivo cancer modeling, thereby advancing the field of organ bioengineering.

Lung transplantation is a critical treatment for patients with end-stage lung diseases like idiopathic pulmonary fibrosis, but challenges such as donor shortages and post-transplant complications persist. Bioengineered lungs, integrating patient-specific cells into decellularized animal scaffolds, present a promising alternative. Despite progress in using bioengineered lungs in animal models, functionality and structure remain immature. This protocol addresses a critical barrier in organ bioengineering: the need for a cost-effective experimental platform. By using mouse models instead of larger animals like rats or swine, researchers can significantly reduce the resources required for each experiment, accelerating research progress. The protocol outlines a detailed procedure for lung bioengineering using mouse heart-lung blocks and human primary cells, focusing on isolation strategy for the mouse heart-lung block, decellularization, bioreactor setup, perfusion-based organ culture, and orthotopic transplantation of bioengineered lungs. This mouse-scale platform not only reduces experimental costs but also provides a viable framework for optimizing cell types and numbers for recellularization, testing different cell types using histological and molecular methods, and ensuring blood flow post-transplantation. The method holds potential for broad applications, including studying cell interactions in three-dimensional culture conditions, cell-matrix interactions, and ex vivo cancer modeling, thereby advancing the field of organ bioengineering. SUMMARY This paper describes how to create bioengineered mouse lungs using the decellularization and recellularization methods. It also describes subsequent orthotopic lung transplantation in detail.

Whole lung engineering and the transplantation of its products is an ambitious goal and ultimately a viable solution for alleviating the donor-shortage crisis for lung transplants. There are several limitations currently impeding progress in the field with a major obstacle being efficient revascularization of decellularized scaffolds, which requires an extremely large number of cells when using larger pre-clinical animal models. Here, we developed a simple but effective experimental pulmonary bioengineering platform by utilizing the lung as a scaffold. Revascularization of pulmonary vasculature using human umbilical cord vein endothelial cells was feasible using a novel in-house developed perfusion-based bioreactor. The endothelial lumens formed in the peripheral alveolar area were confirmed using a transmission electron microscope. The quality of engineered lung vasculature was evaluated using box-counting analysis of histological images. The engineered mouse lungs were successfully transplanted into the orthotopic thoracic cavity. The engineered vasculature in the lung scaffold showed blood perfusion after transplantation without significant hemorrhage. The mouse-based lung bioengineering system can be utilized as an efficient ex-vivo screening platform for lung tissue engineering.

Purposes: Delayed chest closure (DCC) is a widely accepted procedure in the context of lung transplantation (LTx); yet there are few reports detailing its long-term survival and clinical outcomes. Methods: We reviewed the medical records of recipients who underwent deceased-donor lung transplantation (LTx) at Tohoku University Hospital. Long-term survival, including overall survival, freedom from chronic lung allograft dysfunction (CLAD), and CLAD-free survival and the clinical outcomes of graft function and physical performance and constitution were reviewed in recipients with DCC. Results: Between 2009 and 2022, 116 patients underwent LTx, 33 of whom (28.4%) required DCC. The intra—and post-operative courses of the recipients who required DCC were more complicated than those of the recipients who underwent primary chest closure (PCC), with frequent volume reduction surgery and longer periods of invasive mechanical ventilation. Pulmonary vascular disease was considered a risk factor for these complications and DCC. Nonetheless, long-term survival and graft functions were comparable between the DCC and PCC groups. The physical performance and constitution of recipients who required DCC continued to improve, and by 2 years after transplantation, exhibited almost no difference from those who underwent PCC. Conclusions: In view of the profoundly complicated intra- and post-operative courses, DCC should be performed cautiously and only when clinically indicated, despite which it can result in equivalent long-term survival and acceptable outcomes to PCC.