An Experimental Study Of Minimally Invasive Lung Volume Reduction Medicine

Objectives:COPD is a frequent chronic respiratory disease . Its morbidity ,mutilation and mortality is fairly high in the world . It is the fourth-leading cause of death in the world. COPD affects 3% of the general population who are more than fifteen-year old and 8.2% of the general population who are more than forty-year old in our country. Emphysema is the main pathotype. Its treatment includes expectant treatment (drug therapy, oxygen, smoking cessation, rehabilitation) and surgical treatment (lung transplantation, bullae resection, lung volume reduction surgery ). BLVR is a new minimally invasive lung volume reduction medicine . Implanting one-way flap stent and perfusing biocompatible fibrin-base glue using bronchoscopy was proved its efficacy, but the mechanism of lung volume reduction still has dispute and it has defect (low atelectasis rate ,glue location was not certain and was expectorated easily).So how to improve the therapeutic efficacy of minimally invasive lung volume reduction is a key problem for scientists. This study evaluated the effect and safety of minimally invasive lung volume reduction (MILVR) using dead end stent designed independently and biocompatible fibrin-base glue and observe dead end stent biocompatibility.Material and methods:The animal study was carried out in Li Hui Li hospital affiliated to medical college of Ning Bo University from March to Augest 2009. The dead end stent designed independently came from Nanking minimally invasive biology limited company. 28 rabbits were used in this experiment. The control group had 6 animals used pure bronchoscopy examination ;The experimential group had 22 animals used minimally invasive lung volume reduction. Totally 22 stents were implanted in the target bronchi of 22 healthy male rabbits. Artery blood gas analysis ,CT scan and lung histopathological were performed at 1,2 and 4 weeks postoperation respectively. Descriptive analysis comparing the differences used the t test (for measurement data variables).Results:1. Postoperative general state : All the stents and biocompatible fibrin-base glue were implanted successfully and no glue were expectorated except one stent was ablated. No animal was dead, no severe complications were observed, and the procedure was well tolerated.2. Blood gas analysis: Comparing to preoperative blood gas analysis, postoperative of which have no significant difference at each time-point(p>0.05) except one week postoperative (p<0.05).3. Chest CT scan: CT scan showed that for more than 85.6%(18/21)of the stents, the target lung tissue had collapsed .No pneumothorax and obstructive pneumonia were observed.4. Pathohistology: Target lung lobars were collapsed under macroscopic observation. The bronchi wall mucosa and hypomucosa surrounding the stent were thinningz, part exuviation, little fibroblast proliferation, and no obvious granulation tissue proliferation. Lung histopathology of the distal of the stents showed that the alveolar space was deflated and collapsed. Lymphocytes and monocytes infiltrated the interstitial tissue with some degree of fibrosis. No necrosis and abscess were formed.Conclusions:Operative procedure through minimally invasive lung volume reduction with dead end stent designed independently and biocompatible fibrin-base glue was effective and safe, trauma is little,complications are few ,and so this method may be useful in the treatment of severe emphysema in the near future.