I Definition.
Spontaneous pneumothorax is caused by rupture of the lung parenchyma or visceral pleura without exogenous or intervening factors, resulting in accumulation of gas in the pleural cavity.
II Etiology and pathogenesis.
The occurrence of pneumothorax is associated with a sudden increase in the intra-alveolar pressure of the lesion. In general, the pressure required to cause rupture of normal alveoli is 7.8-13.7 kPa (58.6-103.0 mmHg). Alveoli and alveoli with lesions can withstand much less pressure than normal alveoli and are therefore prone to rupture.
The following conditions are prone to pneumothorax: 1 violent cough, increased abdominal pressure 2 respiratory tract infection caused by local airway semi-obstruction, gas can only enter the distal alveoli, and poor discharge, so that the distal alveoli pressure rise 3 asthma persistent state 4 mechanical ventilation, continuous positive pressure in the airway, more than the pressure limit of the lesion alveoli can withstand 5 some physical activities, such as sudden exertion, sudden change of position, yawning etc.
Spontaneous pneumothorax is divided into primary (PSP) and secondary (SSP) according to the cause of gas spillage into the pleural cavity.
PSP refers to spontaneous pneumothorax without previous primary pulmonary disease, which is usually caused by the rupture of subpleural alveoli in the apical layer of the lung and develops suddenly, mostly in adolescents, especially those with long and thin stature or flat chest type. The vast majority of patients with spontaneous pneumothorax have pulmonary alveoli located in the upper lobe of the apical lung.
With regard to the etiology, Withers believes that the rapid growth of the lungs in long and lean patients causes local ischemia in the apical lung, which is prone to nutritional blood supply disorders, and coupled with the large ventilation volume, easily leads to the destruction of alveolar elastic fibers to form apical pneumothorax; in tall patients, the negative pressure in the pleural cavity of both upper lobes of the lungs, especially the apical lung, is greater than that in the base of the lung, and the pressure transmitted by the apical lung is high, resulting in the rupture of dilated alveoli to form pneumothorax.
Studies have shown that abnormal development of thoracic connective tissue and pulmonary elastic fibers causes biomechanical changes in the thorax and lung tissue, which may be one of the main reasons why adolescents with flat chest are prone to spontaneous pneumothorax. Therefore, in young and middle-aged patients, bilateral pulmonary alveolar formation is most common, and some patients present with unilateral pneumothorax but also have a history of unilateral pneumothorax on the contralateral side, with a probability of 87.7% reported in the literature. Therefore, many studies have reported that the results of minimally invasive bilateral pneumonectomy treatment in young and middle-aged patients with unilateral spontaneous pneumothorax at the same time are worthy of recognition.
SSP refers to pneumothorax secondary to primary lung disease, mainly due to rupture of intrapulmonary type of pulmonary blister, which penetrates the dirty pleura, usually secondary to inflammatory lesions of small bronchi, and often coexists with chronic obstructive pulmonary emphysema. With the enlargement of the pulmonary blister, patients may develop progressively more active shortness of breath, chest tightness and other symptoms, which reduces the quality of life of patients.
Other diseases: tuberculosis, lung abscess, lung cancer, infection, spontaneous pneumothorax during menstruation (first reported by Maurer in 1968 and officially named by Lillingto et al. in 1972), patients with acquired immunodeficiency syndrome (usually occurring on the basis of Pneumocystis carinii pneumonia PCP, pneumothorax occurs in about 6% of AIDS patients with PCP, with a mortality rate of up to 50%, and in patients requiring ventilatory (mortality rate approaching 90% in patients requiring ventilation support), etc.
III. Treatment
Some patients can be treated conservatively by internal medicine or by performing closed chest drainage to make them absorb and heal by themselves, but often the root cause of pneumothorax cannot be removed. However, about 25% of patients have recurrence, and the probability of pneumothorax occurring again after the second recurrence is as high as 50%, and surgery can avoid or reduce recurrence.
Although the traditional open thoracotomy can completely remove the lesion, it is not the first choice for treatment because of the large trauma, long recovery time and aesthetic impact.
In 1991, Nathanson first reported video-assisted thoraco-scopic surgery (VATS) for the treatment of pulmonary herpes. With the development of minimally invasive technology and the popularization of equipment in China in recent years, the application of TV thoracoscopy in the treatment of spontaneous pneumothorax has become increasingly mature.
VATS has the advantages of clear vision, small trauma, short time, thorough treatment, mild pain, quick recovery and short hospitalization period, and has become the standard of surgical treatment for spontaneous pneumothorax.
Indications for surgery: spontaneous pneumothorax in young people with first or recurrent episodes; moderate to severe air leakage even after 5-10 d of conventional closed chest drainage.
Classical thoracoscopic surgery was performed by a three-hole operation group: a 1.5 cm long observation hole was made through the 7th intercostal line in the mid-axillary line, and a 1.5 cm operation hole was made through the 4th intercostal line in the anterior axillary line and the 5th intercostal line in the posterior axillary line, and a 10 mm 30° thoracoscopic lens was inserted into the observation hole.
Double-port surgery group: a 1.5 cm observation hole was made through the 7th intercostal space in the mid-axillary line, and a 2 cm operating hole was made through the 4th intercostal space in the anterior axillary line, without an operating hole in the posterior axillary line. A 10 mm 30° thoracoscopic lens was inserted into the observation hole.
The 5th or 6th intercostal operating hole between the posterior axillary line and the scapular line is highly susceptible to bleeding because of the developed local muscles and the need to pierce the back muscles such as the latissimus dorsi, serratus anterior, and intercostal muscles to enter the trocar through this hole, and once the muscular nutritional branch or intercostal vessels are injured, it is impossible to completely stop bleeding due to the small incision and muscle hypertrophy. a potential risk factor during surgery.
The amount of intraoperative bleeding, postoperative pain sensation score, amount of analgesics, and hospital stay were significantly less in the two-hole surgery group than in the three-hole surgery group (all P < 0.05); the differences in operating time and postoperative chest tube retention time between the two groups were not statistically significant (all P > 0.05).