Living lobar lung transplantation was developed as an alternative to deceased donor lung transplantation because of the shortage of acceptable donor organs.^1,2 In living lobar lung transplantation, two healthy donors are selected—one to undergo removal of the right lower lobe and the other to undergo removal of the left lower lobe. These lobes then are implanted in the recipient in place of whole right and left lungs. This technique has proved to be beneficial to a group of patients who otherwise would have succumbed to disease while awaiting lungs from a conventional deceased donor.³

Living lobar lung transplant candidates should meet the standard criteria for deceased donor lung transplantation and be listed on the Organ Procurement and Transplantation Network lung transplantation waiting list.⁴ The expectation for potential recipients should be that they will either die before a deceased donor lung becomes available or become too ill to undergo any sort of organ transplant procedure. In the United States, cystic fibrosis has been the most common indication for living lobar lung transplantation. Other indications have included primary pulmonary arterial hypertension (PAH), pulmonary fibrosis, bronchopulmonary dysplasia, and obliterative bronchiolitis.² In Japan, which is the country where the second highest numbers of these cases have been performed and where cystic fibrosis is very rare, the most frequent indications have been PAH, obliterative bronchiolitis (including a subset of patients with prior hematopoietic stem cell transplantation), and interstitial pneumonia.⁵

The goals of donor selection are to identify donors with excellent health, adequate pulmonary reserve for lobar donation, an emotional attachment to the recipient, and a willingness to accept the risks of donation without coercion. Our criteria for donation also include age between 18 and 55 years, no history of thoracic procedures on the side to be donated, and excellent general health. Donors taller than the recipient are favored over donors of the same or lesser height because they have the potential to provide larger lobes. Initially, only the mother and father of the recipient were considered as donors; however, lobes from siblings, extended family members, and unrelated individuals who can demonstrate an emotional attachment to the recipient are also presently considered. A psychosocial interview is conducted. Potential donors are interviewed both separately and with the potential recipient’s family to ascertain interpersonal dynamics. Elements of the interview include the motivation to donate, pain tolerance, feelings regarding donation should the recipient expire, and the ability of the potential donor to be separated from family and career obligations. Since an element of coercion always can exist between a potential donor and the recipient and/or the recipient’s family, any potential donor who discloses that he or she feels any pressure to donate after careful consultation and explanation of the procedure is denied for unspecified reasons, thus preventing untoward feelings between the family, recipient, and potential donor.

After the psychosocial evaluation, suitable potential donors undergo blood typing for compatibility as well as chest radiography and spirometry to assess lung size and function. This preliminary screening reduces costs because it allows for the evaluation of only a limited number of potential donors. A more thorough medical workup, including routine transplant serologies (i.e., HIV, VDRL, cytomegalovirus, Epstein–Barr virus, and hepatitis), electrocardiogram, echocardiogram, quantitative ventilation/perfusion scanning, and high-resolution chest CT scanning, is conducted after the preliminary screening is completed and found to be acceptable.

After identification of two suitable donors, one is chosen to undergo right lower lobectomy and the other, left lower lobectomy. The right lower lobe is usually selected from the larger donor, whereas the donor with the more complete fissure on the left is chosen to donate that side if the donors are of the same height. Occasionally, an acceptable donor will have a history of prior thoracic procedures, trauma, or infection. In this case, the contralateral side is chosen for donation. Computerized tomography chest scanning and spirometry can be used to estimate the subsequent resulting lung volume in the recipient. Size matching has also been performed utilizing three-dimensional CT volumetric reconstruction imaging.⁵ Regardless of whether functional or anatomical methods (or both) are used to determine the appropriate size match between the donor and the recipient, the goal is to avoid the extremes of transplanting an insufficient amount of lung tissue due to undersized lobes versus implanting oversized grafts, the latter of which is a greater risk when the recipient is a child. While human leukocyte antigen (HLA) matching is not required for donor selection, a prospective crossmatch to rule out the presence of anti-HLA antibodies is performed.

The performance of living lobar lung transplantation involves three simultaneous operations: two donor lobectomies, the recipient bilateral pneumonectomy, and lobar implantation. The operative goals of living-donor lung transplantation are to avoid morbidity to the healthy volunteer lobe donor while providing adequate tissue margins for implantation in the recipient.⁶ The lobar vascular and bronchial anatomy of the right and left lower lobes are the most suitable for lobar transplantation.

The Donor Lobectomy

The donors are placed in separate ORs, and epidural catheters are inserted for postoperative pain control. After induction of anesthesia, fiberoptic bronchoscopy is performed to exclude mucosal abnormalities or alterations in bronchial anatomy. The single-lumen endotracheal tube is replaced with a double-lumen tube, and the patient is positioned in the appropriate lateral decubitus position. Prostaglandin E₁ is administered intravenously to dilate the pulmonary bed, and the dosage is adjusted to maintain a systolic blood pressure of 90 to 100 mm Hg. There are important differences in performing a lobectomy for lobar transplantation in comparison with that for cancer or infection. The lobe must be removed with an adequate cuff of bronchus and pulmonary artery and vein to permit successful implantation into the recipient while allowing closure of these structures without compromise in the donor.

Donor Right Lower Lobectomy

The donor lung is deflated, and the chest is entered through a standard posterolateral thoracotomy through the fourth or fifth interspace. The lung is carefully inspected to exclude unsuspected pathology. Excellent exposure is mandatory, allowing dissection of hilar structures without excessive manipulation of the graft. The inferior pulmonary ligament is taken down, and the pleura is opened around the hilum. Dissection in the fissure characterizes anatomic variants and identifies the pulmonary arteries to the right lower and right middle lobes. The relationship between the superior segmental artery to the right lower lobe and middle lobe artery should be visualized (Fig. 110-1). Commonly, the middle lobe has two arteries, with the smaller artery having a more distal origin than the superior segmental artery to the lower lobe. In this case, the smaller artery may be ligated and divided. Ideally, there will be sufficient distance between the takeoff of the middle lobe artery and the superior segmental artery of the right lower lobe to permit placement of a vascular clamp distal to the middle lobe artery, thus enabling a sufficient vascular cuff for the pulmonary arterial anastomosis at implantation.

After confirming that the inferior pulmonary vein does not receive venous drainage from the right middle lobe, the pericardium surrounding the inferior pulmonary vein is incised. This dissection allows a vascular clamp to be placed on the left atrium and the inferior pulmonary vein to be cut with an adequate cuff on the donor lobe (Fig. 110-2). When the vascular dissections are complete, the fissures are stapled using a 75-mm nonvascular stapler or a 45-mm GIA thoracoscopic stapler. Between 5000 and 10,000 units of heparin and 500-mg methylprednisolone are administered intravenously, and the lung is reinflated and ventilated for 5 to 10 minutes to permit the drugs to circulate through the lung. The lung then is deflated. To avoid vascular congestion of the pulmonary allograft, a vascular clamp is placed first on the pulmonary artery and subsequently on the left atrial side of the inferior pulmonary vein, optimizing the length of the venous cuff for pulmonary venous anastomosis. The pulmonary artery is transected at a point that will leave an adequate vascular cuff for the anastomosis while leaving sufficient length to permit repair without compromising the remaining pulmonary arterial branches. The inferior pulmonary vein is transected with a small cuff of left atrium. The bronchus to the right lower lobe now should be exposed. Minimizing dissection around the bronchus preserves blood supply to both the donor lobe and the remaining lung. The right middle lobe bronchus is identified, and the bronchus to the lower lobe is transected tangentially. The incision begins in the bronchus intermedius above the bronchus to the superior segment of the right lower lobe and moves obliquely to a point just below the takeoff of the right middle lobe bronchus (Fig. 110-3).