Right and left inverted lobar lung transplantation

Evolution of Three-Dimensional Computed Tomography Imaging in Thoracic Surgery

Radiologic reconstruction technology allows the wide use of three-dimensional (3D) computed tomography (CT) images in thoracic surgery. A minimally invasive surgery has become one of the standard therapies in thoracic surgery, and therefore, the need for preoperative and intraoperative simulations has increased. Three-dimensional CT images have been extensively used, and various types of software have been developed to reconstruct 3D-CT images for surgical simulation worldwide. Several software types have been commercialized and widely used by not only radiologists and technicians, but also thoracic surgeons. Three-dimensional CT images are helpful surgical guides; however, in almost all cases, they provide only static images, different from the intraoperative views. Lungs are soft and variable organs that can easily change shape by intraoperative inflation/deflation and surgical procedures. To address this issue, we have developed a novel software called the Resection Process Map (RPM), which creates variable virtual 3D images. Herein, we introduce the RPM and its development by tracking the history of 3D CT imaging in thoracic surgery. The RPM could help develop a real-time and accurate surgical navigation system for thoracic surgery.

Living-donor lobar lung transplantation

Living-donor lobar lung transplantation (LDLLT) is indicated for critically ill patients who would not survive the waiting period in the case of severe brain-dead donor shortage. It is essential to confirm that potential donors are willing to donate without applying psychological pressure from others. In standard LDLLT, the right and left lower lobes donated by 2 healthy donors are implanted into the recipient under cardiopulmonary support. LDLLT can be applied to various lung diseases including restrictive, obstructive, infectious, and vascular lung diseases in both adult and pediatric patients if size matching is acceptable. Functional size matching by measuring donor pulmonary function and anatomical size matching by 3-dimensional computed tomography volumetry are very useful. When 2 donors with ideal size matching are not available, various transplant procedures, such as single lobe, segmental, recipient lobe-sparing, and inverted lobar transplants are valuable options. There seems to be immunological advantages in LDLLT as compared to cadaveric lung transplantation (CLT). Unilateral chronic allograft dysfunction is a unique manifestation after bilateral LDLLT, which may contribute to better prognosis. The growth of adult lung graft implanted into growing pediatric recipients is suggested by radiologic evaluation. Although only 2 lobes are implanted, postoperative pulmonary function is equivalent between LDLLT and CLT. The long-term outcome after LDLLT is similar to or better than that after CLT. The author has performed 164 LDLLTs resulting in 71.6% survival rate at 10 years. All living-donors returned to their previous life styles. Because of possible serious morbidity in donors, LDLLT should be applied only for critically ill patients.

Living-donor Segmental Lung Transplantation for Pediatric Patients

OBJECTIVE

The preset study evaluated the outcome of living-donor segmental lung transplantation for pediatric patients.

METHODS

Between August 2009 and May 2021, we performed living-donor segmental lung transplantation in 6 critically ill pediatric patients, including 1 patient on a ventilator alone and another patient on a ventilator and extracorporeal membrane oxygenation (ECMO). There were 4 male and 2 female patients, with a median age of 7 years (range, 4-15 years) and a median height of 112.7 cm (range, 95-125.2 cm). The diagnoses included complications of allogeneic hematopoietic stem cell transplantation (n = 4) and pulmonary fibrosis (n = 2). All patients received bilateral lung transplantation under cardiopulmonary bypass. A basal segment and a lower lobe were implanted in 3 patients, and a basal segment and an S6 segment were implanted in the other 3 patients. In 2 patients, the right S6 segmental graft was horizontally rotated 180° and implanted as the left lung.

RESULTS

Among the 9 segmental grafts implanted, 7 functioned well after reperfusion. Two rotated S6 segmental grafts became congestive, with 1 requiring graft extraction and the other venous repair, which was successful. There was 1 hospital death (14 days) due to sepsis and 1 late death (9 years) due to leukoencephalopathy. The remaining 4 patients are currently alive at 9 months, 10 months, 1.3 years, and 1.9 years.

CONCLUSIONS

Living-donor segmental lung transplantation was a technically difficult but feasible procedure with acceptable outcomes for small pediatric patients with chest cavities that were too small for adult lower lobe implantation.

Right lung transplantation with a left-to-right inverted anastomosis in a rat model

Objective

Right lung transplantation in rats has been attempted occasionally, but the technical complexity makes it challenging to apply routinely. Additionally, basic research on inverted lobar lung transplantation is scarce because of the lack of a cost-effective experimental model. We first reported right lung transplantation in a rat model using left-to-right inverted anastomosis to imitate the principle of clinically inverted lung transplantation.

Methods

Right lung transplantation was performed in 10 consecutive rats. By using a 3-cuff technique, the left lung of the donor rat was implanted into the right thoracic cavity of the recipient rat. The rat lung graft was rotated 180° along the vertical axis to achieve anatomic matching of right hilar structures. Another 10 consecutive rats had received orthotopic left lung transplantation as a control.

Results

All lung transplantation procedures were technically successful without intraoperative failure. One rat (10%) died of full pulmonary atelectasis after right lung transplantation, whereas all rats survived after left lung transplantation. No significant difference was observed in heart-lung block retrieval (8.6 ± 0.8 vs 8.4 ± 0.9 minutes), cuff preparation (8.3 ± 0.9 vs 8.7 ± 0.9 minutes), or total procedure time (58.2 ± 2.6 vs 56.6 ± 2.1 minutes) between the right lung transplantation and standard left lung transplantation groups (P > .05), although the cold ischemia time (14.2 ± 0.9 vs 25.5 ± 1.7 minutes) and warm ischemia time (19.8 ± 1.5 vs 13.7 ± 1.8 minutes) were different (P < .001).

Conclusions

Right lung transplantation with a left-to-right inverted anastomosis in a rat model is technically easy to master, expeditious, and reproducible. It can potentially imitate the principle of clinically inverted lung transplantation and become an alternative to standard left lung transplantation.

Living-donor lobar lung transplantation

Living-donor lobar lung transplantation (LDLLT) has become an important life-saving option for patients with severe respiratory disorders, since it was developed by a group in the University of Southern California in 1993 and introduced in Japan in 1998 in order to address the current severe shortage of brain-dead donor organs. Although LDLLT candidates were basically limited to critically ill patients who would require hospitalization, the long-term use of steroids, and/or mechanical respiratory support prior to transplantation, LDLLT provided good post-transplant outcomes, comparable to brain-dead donor lung transplantation in the early and late phases. In Kyoto University, the 5- and 10-year survival rates after LDLLT were reported to be 79.0% and 64.6%, respectively. LDLLT should be performed under appropriate circumstances, considering the inherent risk to the living donor. In our transplant program, all living donors returned to their previous social lives without any major complications, and living-donor surgery was associated with a morbidity rate of <15%. Both functional and anatomical size matching were preoperatively performed between the living-donor lobar grafts and recipients. Precise size matching before surgery could provide a favorable pulmonary function and exercise capacity after LDLLT. Various transplant procedures have recently been developed in LDLLT in order to deal with the issue of graft size mismatching in recipients, and favorable post-transplant outcomes have been observed. Native upper lobe-sparing and/or right-to-left inverted transplantation have been performed for undersized grafts, while single-lobe transplantation has been employed with or without contralateral pneumonectomy and/or delayed chest closure for oversized grafts.

Current trends in thoracic surgery

Thoracic surgery has evolved drastically in recent years. Although thoracic surgeons mainly deal with tumorous lesion in the lungs, mediastinum, and pleura, they also perform lung transplantation surgery in patients with end-stage lung disease. Herein, we introduce various major current topics in thoracic surgery. Minimally invasive surgical procedures include robot-assisted thoracic surgery and uniportal video-assisted thoracic surgery. Novel techniques for sublobar resection include virtual-assisted lung mapping, image-guided video-assisted thoracic surgery, and segmentectomy using indocyanine green. Three-dimensional (3D) computed tomography (CT) simulation consists of surgeon-friendly 3D-CT image analysis systems and new-generation, dynamic 3D-CT imaging systems. Updates in cadaveric lung transplantation include use of marginal donors, including donation after circulatory death, and ex vivo lung perfusion for such donors. Topics in living donor lobar lung transplantation include size matching, donor issues, and new surgical techniques. During routine clinical practice, thoracic surgeons encounter various pivotal topics related to thoracic surgery, which are described in this report.

Quantity and quality of antigravity muscles in patients undergoing living-donor lobar lung transplantation: 1-year longitudinal analysis using chest computed tomography images

Background

Skeletal muscle dysfunction is a common feature in patients with severe lung diseases. Although lung transplantation aims to save these patients, the surgical procedure and disuse may cause additional deterioration and prolonged functional disability. We investigated the postoperative course of antigravity muscle condition in terms of quantity and quality using chest computed tomography.

Methods

35 consecutive patients were investigated for 12 months after living-donor lobar lung transplantation (LDLLT). The erector spinae muscles (ESMs), which are antigravity muscles, were evaluated, and the cross-sectional area (ESM_CSA) and mean attenuation (ESM_CT) were analysed to determine the quantity and quality of ESMs. Functional capacity was evaluated by the 6-min walk distance (6MWD). Age-matched living donors with lower lobectomy were evaluated as controls.

Results

Recipient and donor ESM_CSA values temporarily decreased at 3 months and recovered by 12 months post-operatively. The ESM_CSA of recipients, but not that of donors, surpassed baseline values by 12 months post-operatively. Increased ESM_CSA (ratio to baseline ≥1) may occur at 12 months in patients with a high baseline ESM_CT. Although the recipient ESM_CT may continuously decrease for 12 months, the ESM_CT is a major determinant, in addition to lung function, of the postoperative 6MWD at both 3 and 12 months.

Conclusion

The quantity of ESMs may increase within 12 months after LDLLT in recipients with better muscle quality at baseline. The quality of ESMs is also important for physical performance; therefore, further approaches to prevent deterioration in muscle quality are required.

The quantity of antigravity muscles in patients undergoing lung transplantation (LTx) will increase within 1 year after LTx. The quality of muscles is important for increase of muscle quantity as well as physical performance.https://bit.ly/3bItfB9

Native upper lobe-sparing living-donor lobar lung transplantation maximizes respiratory function of the donor graft

BACKGROUND

We have developed a novel method for native upper lobe-sparing living-donor lobar lung transplantation (LDLLT) to overcome a small-for-size graft in standard LDLLT with acceptable results. We hypothesized that grafts implanted with this procedure might work more efficiently than those in standard lobe transplantation.

METHODS

Bilateral LDLLT was performed in 31 patients with a functional graft matching of less than 60% at our institution between August 2008 and December 2015. Of these, 22 patients were available for evaluation of pulmonary function more than 1 year later: 15 undergoing standard LDLLT with less than 60% functional matching and 7 undergoing native upper lobe-sparing LDLLT.

RESULTS

Overall survival at 2 years was 87.5% in the lobe-sparing LDLLT patients and 79.0% in the standard LDLLT patients (p = 0.401). The median forced vital capacity size-matching levels were 50.7% ± 1.6% in the standard LDLLT and 45.2% ± 2.3% in the sparing LDLLT group (p = 0.074). The 1-year and 2-year post-operative volume ratios of inspiration to expiration were significantly different between the 2 groups, at 1.76 and 1.45 after standard LDLLT (p = 0.019) vs 2.41 and 2.23 after lobe-sparing LDLLT (p = 0.015).

CONCLUSIONS

The grafts in lobe-sparing LDLLT functioned more effectively than those in standard LDLLT. This advantage was associated with the improvement of pulmonary functions.

Prognostic Factors in Lung Transplantation After Hematopoietic Stem Cell Transplantation

BACKGROUND

Lung transplantation is the final lifesaving option for patients with pulmonary complications after hematopoietic stem cell transplantation (HSCT). Patients undergoing HSCT for hematologic diseases are thought to be high-risk candidates for lung transplantation; therefore, few lung transplants are performed for these patients, and few studies have been reported. This study aimed to describe the characteristics and outcomes of lung transplantation in patients with pulmonary complications after HSCT.

METHODS

We retrospectively investigated 62 patients who underwent lung transplantation after HSCT. All data were collected from 6 lung transplant centers in Japan.

RESULTS

Seventeen patients underwent cadaveric lung transplantation, whereas 45 underwent living-donor lobar lung transplantation (LDLLT). In the LDLLT group, 18 patients underwent LDLLT after HSCT in which one of the donors had also served as a donor for HSCT. Seven patients underwent single LDLLT for which the donor was the same as the patient from whom stem cells were obtained for HSCT. Preoperative hypercapnia was observed in 52 patients (84%). Thirteen patients (21%) required mechanical ventilation preoperatively. Fifty-five patients underwent HSCT for hematologic malignancies, and 4 (7%) relapsed after lung transplantation. The 5-year survival rate was 64.2%. In a multivariable analysis, patients younger than 45 years and those with the same donor for both procedures exhibited significantly better survival (P = 0.012 and 0.041, respectively).

CONCLUSIONS

Lung transplantation for pulmonary complications after HSCT was performed safely and yielded better survival, especially in younger recipients for whom both lung transplantation and HSCT involved the same donor.

Three-dimensional image in lung transplantation

Three-dimensional computed tomography (3D-CT) technologies have been developed and, recently, high-speed and high-quality 3D-CT technologies have been introduced to the field of thoracic surgery. The purpose of this manuscript is to demonstrate the clinical application of 3D-CT technologies in lung transplantation. In Japan, because of the severe donor shortage, living-donor lobar lung transplantation (LDLLT) is essential, in addition to cadaveric lung transplantation. In LDLLT, size matching is a grave issue, since ideal size matching between donor and recipient is usually difficult because of the limited population of potential donor. Size matching using pulmonary function test results has been widely used as a gold standard, but anatomical size matching using 3D-CT volumetry data has also been utilized in LDLLT. In donor lobectomy, 3D-CT images provided a variety of information regarding anatomical variation of pulmonary vessels and bronchial trees preoperatively. These images ensure surgical quality and safety, and they also affect surgical procedures for the recipient. 3D-CT images are also utilized in various aspects of postoperative care, such as detection of chronic lung allograft dysfunction and clarification of its subtypes. Furthermore, preoperative 3D-CT simulation is useful in developing and performing a special surgical procedure, such as right-to-left inverted LDLLT. In conclusion, following the introduction of 3D-CT to the field of thoracic surgery, various 3D-CT images and their application to preoperative simulations have been introduced in lung transplantation. In the near future, this technique will become more prevalent, and frequent use by thoracic surgeons will be seen worldwide in daily practice.

Pulmonary Function and Exercise Capacity in Patients With Flat Chests After Lung Transplantation

BACKGROUND

Severe chest wall deformation is generally a contraindication for lung transplantation; however, it is not known whether patients with flat chests have reduced postoperative exercise capacity and pulmonary function. This study's purpose was to investigate the relationship between preoperative thoracic shape and postoperative exercise capacity and pulmonary function in patients undergoing lung transplantation.

METHODS

Twenty recipients who underwent successful bilateral living-donor lobar lung transplantation were evaluated. To analyze postoperative graft function in relation to preoperative thoracic shape, 40 donor grafts implanted into 20 recipients were divided into two groups: flat chest group and normal chest group. Flat chest is diagnosed when the thoracic anteroposterior diameter to transverse diameter ratio is 1:3 or less.

RESULTS

The ratio of the postoperative forced vital capacity to the preoperatively estimated forced vital capacity was significantly lower in the flat chest group than in the normal chest group 1 year after lung transplantation (p = 0.002). However, there were no significant differences in postoperative 6-minute walk distances between the two groups. Furthermore, the thoracic anteroposterior diameter to transverse diameter ratio in the flat chest group significantly increased after lung transplantation (p = 0.02).

CONCLUSIONS

Although postoperative pulmonary function was significantly poorer for patients with flat chests than for patients with normal chests, their postoperative exercise capacity was equivalent. We also found that flat chest severity significantly improved after lung transplantation. Our study, the first investigating postoperative functional status in patients with flat chests, clearly shows that it is possible to perform lung transplantation in such patients with acceptable outcomes.

Living-related lung transplantation

Living-donor lobar lung transplantation (LDLLT) was developed to deal with the severe shortage of brain dead door for patients who would not survive the long waiting period. In standard LDLLT, right and left lower lobes removed from two healthy donors are implanted into a recipient after right and left pneumonectomies using cardiopulmonary bypass (CPB). The number of LDLLT has decreased in the USA due to the recent change in allocation system for cadaveric donor lungs. For the past several years, most of the reports on LDLLT have been from Japan, where the average waiting time for a cadaveric lung is exceeding 800 days. LDLLT has been performed both for adult and pediatric patients suffering from various end-stage lung diseases including restrictive, obstructive, vascular and infectious lung diseases. Since only two lobes are implanted, size matching is a very important issue. Functional size matching by measuring donor pulmonary function and anatomical size matching by three-dimensional computed tomography (3D-CT) volumetry are very useful. For oversize graft, we have employed several techniques, including single lobe transplantation, delayed chest closure, downsizing the graft, and middle lobe transplantation. In cases of undersize mismatch, native upper lobe sparing transplant or right-left inverted transplant was performed. The 5-, 10- and 15-year survivals were 80.8%, 72.6% and 61.7%, respectively. There was no difference in survival between standard LDLLT and non-standard LDLLT such as single, sparing and inverted transplant. All donors have been discharged without any restrictions. LDLLT is a viable option for very ill patients who would not survive a long waiting time for cadaveric lungs. We have successfully developed various surgical techniques to overcome size mismatching with favorable outcome.

Living Donor Lung Transplantation for Pleuroparenchymal Fibroelastosis

We report the first patient with pleuroparenchymal fibroelastosis (PPFE) to undergo living donor bilateral lobar lung transplantation. The patient was diagnosed with secondary PPFE as a late complication of chemotherapy that included high-dose cyclophosphamide for mature B-cell lymphocytic leukemia. Although the patient maintained complete remission, dry cough and back pain appeared 8 years after the chemotherapy. He had repeated bilateral pneumothoraces, and his respiratory condition gradually deteriorated because of progressive pleural thickening and parenchymal fibrosis. He underwent living-donor bilateral lobar lung transplantation with an inverse transplant on the left side.

Surgical applications of three-dimensional printing: a review of the current literature & how to get started

Three dimensional (3D) printing involves a number of additive manufacturing techniques that are used to build structures from the ground up. This technology has been adapted to a wide range of surgical applications at an impressive rate. It has been used to print patient-specific anatomic models, implants, prosthetics, external fixators, splints, surgical instrumentation, and surgical cutting guides. The profound utility of this technology in surgery explains the exponential growth. It is important to learn how 3D printing has been used in surgery and how to potentially apply this technology. PubMed was searched for studies that addressed the clinical application of 3D printing in all surgical fields, yielding 442 results. Data was manually extracted from the 168 included studies. We found an exponential increase in studies addressing surgical applications for 3D printing since 2011, with the largest growth in craniofacial, oromaxillofacial, and cardiothoracic specialties. The pertinent considerations for getting started with 3D printing were identified and are discussed, including, software, printing techniques, printing materials, sterilization of printing materials, and cost and time requirements. Also, the diverse and increasing applications of 3D printing were recorded and are discussed. There is large array of potential applications for 3D printing. Decreasing cost and increasing ease of use are making this technology more available. Incorporating 3D printing into a surgical practice can be a rewarding process that yields impressive results.

Outcomes of various transplant procedures (single, sparing, inverted) in living-donor lobar lung transplantation

OBJECTIVES

In standard living-donor lobar lung transplantation (LDLLT), the right and left lower lobes from 2 healthy donors are implanted. Because of the difficulty encountered in finding 2 donors with ideal size matching, various transplant procedures have been developed in our institution. The purpose of this retrospective study was to compare outcomes of nonstandard LDLLT with standard LDLLT.

METHODS

Between June 2008 and January 2016, we performed 65 LDLLTs for critically ill patients. Functional size matching was performed by estimating graft forced vital capacity based on the donor's measured forced vital capacity and the number of pulmonary segments implanted. For anatomical size matching, 3-dimensional computed tomography volumetry was performed. In cases of oversize mismatch, single-lobe transplant or downsizing transplant was performed. In cases of undersize mismatch, native upper lobe sparing transplant or right-left inverted transplant was performed. In right-left inverted transplants, the donor's right lower lobe was inverted and implanted into the recipient's left chest cavity.

RESULTS

Twenty-nine patients (44.6%) received nonstandard LDLLT, including 12 single-lobe transplants, 7 native upper lobe sparing transplants, 6 right-left inverted transplants, 2 sparing + inverted transplants, and 2 others. Thirty-six patients (57.4%) received standard LDLLT. Three- and five-year survival rates were similar between the 2 groups (89.1% and 76.6% after nonstandard LDLLT vs 78.0% and 71.1% after standard LDLLT, P = .712).

CONCLUSIONS

Various transplant procedures such as single, sparing and inverted transplants are valuable options when 2 donors with ideal size matching are not available for LDLLT.

Current status and problems of lung transplantation in Japan

Lung transplantation has been performed worldwide and recognized as an effective treatment for patients with various end-stage lung diseases. Shortage of lung donors is one of the main obstacles in most of the countries, especially in Japan. Every effort has been made to promote organ donation during the past 20 years. In 2010, Japanese transplant low was revised so that the family of the brain dead donors can make a decision for organ donation. Since then, the number of cadaveric lung donor has increased by 5-fold. However, the average waiting time is still more than 800 days resulting in considerable number of deaths on the waiting list. Lung transplantation in the use of donation after cardiac death (DCD) has now been increasingly performed in Europe, Australia and North America with promising results. However, controlled death is not permitted in Japan making it difficult to accept this strategy. Use of marginal donors is one of the strategies for organ shortage. In Japan, the rate of lung usage is now well over 60% because of careful donor management by medical consultants and aggressive use of marginal donors. Living-donor lobar lung transplantation (LDLLT) has been developed to offset the mismatch between supply and demand for those patients awaiting cadaveric lung transplantation (CLT) and it is often the most realistic option for very ill patients. Between 1998 and 2015, lung transplantation has been performed in 464 patients (55 children, 419 adults) at 9 lung transplant centers in Japan. CLT was performed in 283 patients (61%) and LDLLT was performed in 181 patients (39%). The 5-year survival was 72.3% and 71.6%, respectively. Of note, only seven children received CLT. In conclusion, lung transplantation in Japan has grown significantly with excellent results but the shortage of cadaveric lung donor remains to be an important unsolved problem. LDLLT is often the only realistic option for very ill patients especially for children.

Update on three-dimensional image reconstruction for preoperative simulation in thoracic surgery

BACKGROUND

Three-dimensional computed tomography (3D-CT) technologies have been developed and refined over time. Recently, high-speed and high-quality 3D-CT technologies have also been introduced to the field of thoracic surgery. The purpose of this manuscript is to demonstrate several examples of these 3D-CT technologies in various scenarios in thoracic surgery.

METHODS

A newly-developed high-speed and high-quality 3D image analysis software system was used in Kyoto University Hospital. Simulation and/or navigation were performed using this 3D-CT technology in various thoracic surgeries.

RESULTS

Preoperative 3D-CT simulation was performed in most patients undergoing video-assisted thoracoscopic surgery (VATS). Anatomical variation was frequently detected preoperatively, which was useful in performing VATS procedures when using only a monitor for vision. In sublobar resection, 3D-CT simulation was more helpful. In small lung lesions, which were supposedly neither visible nor palpable, preoperative marking of the lesions was performed using 3D-CT simulation, and wedge resection or segmentectomy was successfully performed with confidence. This technique also enabled virtual-reality endobronchial ultrasonography (EBUS), which made the procedure more safe and reliable. Furthermore, in living-donor lobar lung transplantation (LDLLT), surgical procedures for donor lobectomy were simulated preoperatively by 3D-CT angiography, which also affected surgical procedures for recipient surgery. New surgical techniques such as right and left inverted LDLLT were also established using 3D models created with this technique.

CONCLUSIONS

After the introduction of 3D-CT technology to the field of thoracic surgery, preoperative simulation has been developed for various thoracic procedures. In the near future, this technique will become more common in thoracic surgery, and frequent use by thoracic surgeons will be seen in worldwide daily practice.