The pulmonary bleb is a small subpleural collection of air located within the layers of the visceral pleura. Blebs represent the coalescence of air from small ruptures of terminal alveoli that have dissected through the interstitium to form a small subpleural collection. Such lesions may present symptomatically with a spontaneous pneumothorax. A nontraumatic or iatrogenic pneumothorax in patients without clinically apparent lung disease is termed a “primary spontaneous pneumothorax” (PSP). Although carrying no diagnosis of underlying lung disease, most patients with PSP are found to have multiple subpleural blebs at the time of surgery and smoking has been observed to significantly increase the risk of its development.1,2 Pathologically, bleb formation occurs secondary to mechanical stress from increased intrathoracic pressure in the lung tissue that is predisposed to deformation by weakness of the connective tissue. The lesions that result in spontaneous pneumothorax are located predominantly in the apex of the upper lobe or the apex of the superior segment, where there is increased mechanical stress.3 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 have pneumothorax, infection, or carcinoma. The practical classification of bullous disease separates patients into two primary groups: (1) those with normal underlying lung and a predominant single bulla and (2) 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.4 Thus, the adjacent nonbullous lung tissue becomes atelectatic and nonfunctional. Identification and restoration of this potentially normal underlying lung are key to patient selection and surgical therapy.
GENERAL PRINCIPLES AND PATIENT SELECTION
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. Virtually all operative interventions for blebs, bullae, and giant bullae should now be performed using minimally invasive thoracoscopic techniques.
Initial treatment of patients with spontaneous pneumothorax should be with nonoperative therapy, beginning with chest tube placement. Small, asymptomatic PSPs may be treated with observation or needle aspiration alone, with guidelines citing similar effectiveness and decreased hospital length of stay compared to treatment with chest tube drainage, although this is not recommended in older patients or those with known underlying lung disease.5,6 Smaller percutaneous tubes are ...