The pulmonary bleb is a small subpleural collection of air located within the layers of the visceral pleura. Such lesions usually present symptomatically, heralded by a spontaneous pneumothorax. Blebs represent the coalescence of air from small ruptures of terminal alveoli that have dissected through the interstitium to form a small subpleural collection. Lesions that result in spontaneous pneumothorax are located predominantly in the apex of the upper lobe or the apex of the superior segment. Multiple blebs are often identified. Most patients with blebs are without significant underlying lung disease. Pathologically, bleb formation occurs secondary to mechanical stress from increased intrathoracic pressure in the lung tissue that is predisposed to deformation by congenital weakness of the connective tissue. The bleb often forms at the lung apex, where there is increased mechanical stress.1 Surgical therapy thus is oriented to the apex of the lung.
The bulla is a larger (>1 cm) airspace collection that forms within the parenchyma. The bulla has a fibrous wall and remnants of lung parenchyma, as evidenced by septations and fragments of the alveolar septa. A significant bulla usually presents with symptoms of dyspnea; however, patients also may have pneumothorax, infection, or carcinoma. The practical classification of bullous disease separates patients into two primary groups: those with normal underlying lung and a predominant single bulla versus those with diffuse underlying emphysema and very often multiple bullae. A large single bulla that encompasses more than 30% of the hemithorax is defined as a giant bulla.
The physiology of bulla growth is associated with a parenchymal weakness in the lung that fills preferentially with air. Secondarily, the force of elastic recoil in adjacent lung produces retraction of the surrounding lung and further enlargement of the bulla.2 Thus, the adjacent nonbullous lung tissue becomes atelectatic and nonfunctional. Identification and restoration of this potentially normal underlying lung are keys to patient selection and surgical therapy.
General Principles and Patient Selection
Virtually, all operative interventions for blebs, bullae, and giant bullae should now be performed using minimally invasive thoracoscopic techniques.
Operative procedures for bleb resection are primarily indicated secondary to the pneumothorax. Thus, the operative principle involves identification of the pulmonary bleb, stapled resection, and a procedure to increase pleural symphysis. Initial treatment of patients with spontaneous pneumothorax should be nonoperative therapy, with chest tube placement. Smaller percutaneous tubes are now available that may function as well as larger tubes and are less painful for the patient. Swift resolution of the pneumothorax and air leak should follow, permitting rapid removal of the tube. Failure of the pneumothorax or air leak to resolve in 4 to 7 days warrants consideration of operative intervention. Pneumothorax recurs at a rate of 20% to 30% with nonoperative therapy, with the greatest incidence in the first 2 years.3 Patients who present with recurrent pneumothorax should have surgical intervention because ...