Open Left Upper Lobectomy in an Adult Cystic Fibrosis Patient

Abstract

Cystic Fibrosis (CF) is an autosomal recessive genetic disorder characterized by mutations in the cystic fibrosis transmembrane regulator gene. The pathophysiology is based on abnormal chloride secretion from columnar epithelial cells. As a result, patients with CF have symptoms related to their inability to hydrate secretions in the respiratory tract, pancreas, and intestine, among other organs. In the lung, thick, inspissated secretions give rise to chronic obstructive pulmonary disease characterized by severe pulmonary infections, culminating in respiratory failure. Subacute exacerbations of CF lung disease are treated with antibiotics and various forms of chest physiotherapy. When large areas of the lung develop abscesses or necrosis, surgical treatment is often indicated. Options include lobectomy as a temporizing measure and lung transplantation for end-stage CF lung disease. Here, we present an unusual case of a man with CF whose lung function had remained relatively good until adulthood. His left upper lobe became chronically infected and progressively non-functional. Because the patient's overall lung function was moderately preserved, an open left upper lobectomy was performed to prevent recurrences of subacute infections and subsequent damage to the left lung.

Keywords

Cystic fibrosis; lobectomy; thoracic surgery.

Case Overview

Background

Cystic fibrosis (CF) is an inherited autosomal recessive disorder caused by a mutation in the cystic fibrosis transmembrane regulator (CFTR) gene that affects the lungs, digestive system, sweat glands, and other organs. CFTR gene alteration produces defective chloride channels in cell membranes that lead to electrolyte imbalances and ultimately hyperviscous secretions. These thick secretions impair ciliary clearance in the lungs predisposing patients to chronic respiratory infections and parenchymal destruction and remodeling, leading to chronic obstructive pulmonary disease with bronchiectasis. Additionally, the increased viscosity impairs the secretion of vital pancreatic enzymes, leading to chronic pancreatitis and pancreatic insufficiency. Lack of secreted pancreatic enzymes and biliary juices leads to intestinal malabsorption and chronic organ damage. The mainstay of treatment is control of symptoms and minimizing the progression of organ damage. Recent pharmacological advances have produced CFTR modulators that act to partially restore the function of the CFTR protein. These medications introduce personalized and precise treatment for the management of CF.¹ The full impact of these newer medications remains undiscovered. Patients refractory to medical therapies with immensely diseased focal lung tissue may find relief in surgical resection or lung transplantation.

Patient History

The patient is a 55-year-old male with a history of recurrent pulmonary infections secondary to CF. He is chronically infected and has damage to the left upper lobe. This is resulting in recurrent and chronic pulmonary infections beyond even what we would see with cystic fibrosis. He’s a little bit of an unusual case only because he's reached 50–55 years of age with the diagnosis of CF and has moderately-preserved pulmonary function, although he does have the typical complications that go along with CF including recurrent pulmonary infections.

Going into the operation, it was thought that his lung would likely be stuck to the chest wall and require a significant amount of work to achieve homeostasis. The plan was to do something unusual for a routine lobectomy and use some muscle from his chest wall to reinforce or buttress the bronchial closure because of his underlying plumber issues.

Diagnosis and Imaging

In the United States, diagnosis of CF usually begins at birth as the neonates may fail to pass meconium due to the increased viscosity of the mucus within the gastrointestinal system. If clinical suspicion is low, further screening may be indicated with an immunoreactive trypsinogen assay. If screening tests are positive or clinical suspicion is high, confirmation requires quantitative pilocarpine iontophoresis, also called sweat chloride testing, or CFTR gene mutation testing. Additional physiological testing can be considered to examine the extent of disease, such as nasal potential difference testing, intestinal current measurements, and pulmonary function testing. Continued management and monitoring can be by routine blood work, chest X-rays, chest CTs, PFTs, stool chymotrypsin, and pancreatic elastase.

Options for Treatment

Symptomatic management is the mainstay of treatment, to maintain and improve lung function, fight infections, clear mucus and help breathing. Specifically, respiratory management has many options, including mucolytics (e.g., dornase alpha, hypertonic saline nebulization), bronchodilators, oxygen inhalation therapy, chest physiotherapy, and antibiotics, anti-inflammatory medicines, CFTR modulators . Pancreatic enzymes and supplementation of vitamins may additionally be required depending on gastrointestinal involvement. Additional medications specific to CF modulate and partially restore the CFTR protein function and work in patients with specific CFTR mutations. These medications are given in addition to symptomatic management and in combination with each other. For example, Ivacaftor improves Cl- channel passage in G551D mutants.² Lumacaftor stabilizes the CFTR protein leading to increased functional protein at the cell surface in those with deltaF508 mutants.³ Tezacaftor and Elexacaftor increase mature CFTR protein that reaches the cell membrane at various binding sites.^4,5 Medical therapy regimens unable to prevent severe localized lung disease or recurrent focal infections may indicate the need for surgical intervention. Local operative management is utilized as a temporizing measure; however, definitive surgical therapy via lung transplantation may be indicated. Surgical intervention can be pursued in multiple approaches:

Wedge resection is a surgical procedure involving the removal of a small, wedge-shaped piece of a lung tissue. This non-anatomic resection is usually a pie slice of the diseased portion of a lobe. This approach may not require ligation of contributing pulmonary arteries and veins.

Lobectomy is a surgical removal of a specific but whole lobe. This approach requires ligation of pulmonary arteries, pulmonary veins, and lobar bronchi.

Pneumonectomy is a surgical removal of a lung, either the left or right lung. A variation is a sleeve resection that preserves the ipsilateral lobar bronchus allowing for the sparing and reattachment of unaffected lobe portions.

Lung transplantation is indicated for end-stage lung disease, and it is the third most common indication in adults.⁶ In brief, lung transplant discussions with CF patients begin once a forced expiratory volume in one second (FEV₁) is <50% of predicted. Further criteria include shortened survival markers such as the 6-minute walk test (6MWT) <400 m, hypoxemia at rest, hypercarbia, or severe pulmonary hypertension.⁷

The recommended surgical approach relies on a formal preoperative evaluation to assess pulmonary function and the predicted postoperative (PPO) pulmonary function. Preoperative pulmonary function tests (spirometry, lung volume measurements, and diffusion capacity quantification assess risk). Additionally, other tests such as the stair-climbing test, shuttle walk test, stair climbing altitude, and peak O₂ consumption testing can be used preoperatively to help risk-stratify patients for potential risk of postoperative morbidity or mortality.  Patients with forced expiratory volume in 1 second (FEV₁) less than 800 cc or diffusion capacity of carbon monoxide (DLCO) less than 40% are considered high-risk patients. These patients are better served with sub-lobar resection or nonoperative therapy. If possible, lobectomy should also be avoided in patients with recent myocardial infarction and severe cardiovascular disease.¹¹

PPO pulmonary function is typically assessed in two ways: perfusion lung scanning via quantitative lung scintigraphy or an anatomic method via CT scanning.

Perfusion lung scanning uses lung scintigraphy to estimate PPO lung function based on quantification of perfusion in the retained lung segment (equation below).⁸

PPO FEV₁ = preoperative FEV₁ x (1 – fraction of total perfusion in the resected lung measured on radionuclide perfusion)

An anatomic method is preferred for lobectomy as remaining lung function can be determined based on how many segments are removed from the total number of segments (equation below).⁹

PPO FEV₁ = preoperative FEV₁ x (1 – a/b) where “a” is the number of segments to be resected and “b” is the total number of unobstructed segments (total number of segments is 19: typically, ten on the right and nine on the left).

Surgical Technique

The patient is placed in a right lateral decubitus position, the arm extended anteriorly and superiorly, gliding the scapula away from the fifth interspace, for a posterolateral thoracotomy incision, because it provides considerable exposure to the entire pleural space. The incision is marked a fingerbreadth inferior to the scapula halfway between the posterior border of the scapula and spinal processes and extended along the submammary crease anteriorly between the 5th and 6th ribs. Once through the superficial fascial layers, the first muscle encountered is the latissimus dorsi, divided inferior to the serratus anterior border. The serratus is spared, mobilization is done along the inferior border of the serratus muscle, the chest wall is exposed, and the periosteum of ribs 5 and 6 is peeled back. Preserving the muscle can enhance chest wall stability and improve shoulder function in the early postoperative period, which may be advantageous if a muscle flap is needed later.¹¹

Part of the 6th rib is cut in order to open the thoracic cage for left lung visualization. The 5th intercostal muscle is partially separated for buttressing the airway during closure. Next, it is essential to identify structures such as the left phrenic nerve that courses through the hilum and the aorta that flows posteriorly to the hilum. The dissection continues posteriorly around the hilum to free the pleura to adequately identify the pulmonary artery and vein and the left upper lobe. At the hilum, the superior pulmonary vein is the most anterior structure, and the inferior vein is the most inferior structure. The pleura has been opened anteriorly to find a superior pulmonary vein.¹¹ Once the inferior and superior pulmonary veins are identified, the inferior pulmonary ligament is taken down to allow a complete expansion of the left lower lobe. A 4-0 Prolene suture is used to control hemostasis from a bronchial vein. The dissection continues mobilizing the pleura from the superior part of the hilum, pulmonary artery, and superior pulmonary vein. Additional hemostasis control required the use of 4-0 Prolene sutures for the superior pulmonary vein. In order to further expose the hilum, the superior pulmonary vein is sectioned and stapled. Switching views to the posterior hilum, the apical pulmonary artery branches are identified and tied off using a vascular stapler. From the anterior view, the upper left bronchus is uncovered and stapled. The stapler is again used on the left oblique fissure to help expose before multiple staples are used to delineate and remove the left upper lobe. The thoracic cavity is irrigated, and hemostasis is achieved. The intercostal muscle exposed earlier is then sutured to buttress the bronchial stump and staple line. Two chest tubes are placed before approximating the ribs with sutures. The muscular layer containing the serratus anterior and latissimus dorsi and the skin are closed in a routine manner.

Discussion

Local surgical intervention in patients with CF has long been used as a temporizing measure. It is only indicated in those refractory to medical management and those with localized recurrent disease. A recent case series reported that lobectomy in CF patients with FEV ≤40% of predicted carried a significant risk of mortality and should only be pursued as a last resort in these patients.¹⁰ However, in patients with suitable remaining lung function, it is an appropriate intervention to reduce the rate and severity of infection and future hospitalizations. In patients with diffuse lung disease, focal lung resection is unlikely to benefit, and those patients should be referred for lung transplantation.

Disclosures

Nothing to disclose.

Statement of Consent

The patient referred to in this video article has given their informed consent to be filmed and is aware that information and images will be published online.