Giant bullae are space-occupying lesions that cause compression of the surrounding lung parenchyma with impairment of lung function. The bullae arise from emphysematous projections of destroyed lung tissue. Hence they differ from blebs, which are localized collections of air between visceral pleural layers without underlying parenchymal disease.1 Giant bullae can be classified as three basic morphologic types: Type I bullae have a narrow neck and are superficial, type II are superficial as well but have a broad neck, and type III are both broad and deep.2 Giant bullae usually require surgical resection. A wide range of procedures from open excision to plication, drainage, video-assisted bullectomy, and lung resection can be applied.3 Developments in anesthesia and surgery have enabled surgeons to operate on patients with very limited pulmonary function; however, there is a subgroup of patients who carry a significant risk of prolonged air leak and respiratory complications following resection of giant bullae. In this group of patients a minimally invasive method, known as the Monaldi procedure, can be performed. The Monaldi procedure, named after the surgeon who first applied this technique, was used in the mid and late 20th century for drainage of apically located tuberculous cavities, lung abscesses, and subsequently of giant bullae.4
Most patients who undergo this procedure are heavy smokers of middle to advanced age with a prolonged history of medical treatment. The most common symptoms are dyspnea and chest pain. Giant bullae occupy a significant portion of the intrathoracic space, causing significant compression of adjacent healthy lung tissue. As a result, the physiologic dead space increases and the presence of these bullae aggravate the patient’s symptoms of dyspnea in generalized emphysema.
Secondary pneumothorax and hemoptysis can be the initial presenting complications. If the bulla becomes infected, fever, cough, and increased sputum production may accompany the clinical picture. Preliminary evaluation usually begins with a plain chest radiograph. Giant bullae usually have a concave contour at the base, which can be used to differentiate a bulla from pneumothorax (Fig. 100-1). If the bulla is infected, an air–fluid level is seen. The chest x-ray also may demonstrate a generalized heterogeneous emphysema, areas of scarring secondary to previous infections, and interstitial fibrosis (Fig. 100-2). Standard chest computed tomography (CT) is the best study for delineating the extent of the bulla and the degree of compression of surrounding lung tissue.
The indication for treatment is defined as the presence of symptoms in a space-occupying bulla that is compressing the surrounding lung parenchyma. Ideally, the bulla should occupy greater than one-third of the hemithorax to be suitable for resection. CT scan is the preferred imaging modality for preoperative planning. In addition to visualizing the full extent of the bulla, it can demonstrate pleural and parenchymal scarring, interstitial fibrosis, and the general condition of the remaining lung tissue. Ventilation perfusion scintigraphy also may be helpful.
Pulmonary function testing is conducted to determine the extent of the patient’s obstructive pathology. Those with markedly decreased forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), or diminished diffusion capacity of the lung for carbon monoxide (DLCO) with evidence of hypoxemia and hypercarbia are at increased risk for perioperative complications, and may fail to improve or even worsen with resection. The ideal candidate for surgery is a patient with a peripheral bulla, FEV1 greater than 500 mL, and carbon dioxide tension less than 6.5 kPa who would not tolerate prolonged anesthesia and major open surgery.
Similar to the Monaldi procedure, percutaneous or endoscopic drainage of infected lung bullae also has been performed successfully in very sick patients resulting in spontaneous resolution of bullae.5,6 Individuals with better pulmonary reserve have several options available, and bullectomy by means of video-assisted thoracic surgery (VATS) may be the most appropriate procedure for these patients.
The Monaldi procedure has several advantages. First, no lung tissue is removed. This is especially important in patients with limited lung function. Second, suturing and stapling, which commonly results in prolonged air leak and healing problems in emphysematous lung tissue, is avoided. Third, the procedure can be performed through a limited incision with brief anesthesia which is certainly advantageous in patients with poor lung function.7