Chest ACCP Member Benefits
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Guest Access | Sign In via User Name/Password
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF) Free
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Article Archive
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (5)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Maxfield, R. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Maxfield, R. A.
(Chest. 2004;125:777-783.)
© 2004 American College of Chest Physicians

New and Emerging Minimally Invasive Techniques for Lung Volume Reduction*

Roger A. Maxfield, MD, FCCP

* From the Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, Columbia University College of Physicians & Surgeons, New York, NY.

Correspondence to: Roger A. Maxfield, MD, FCCP, Columbia Presbyterian Eastside, 16 East 60th St, Suite 320, New York, NY 10022-1002; e-mail: ram7{at}columbia.edu


   Abstract
TOP
 Abstract
Introduction
 Bronchoscopic Methods
 Thoracoscopic Techniques
 Conclusion
 References
 
Lung volume reduction surgery (LVRS) has been shown to improve pulmonary function, exercise capacity, quality of life, and survival in selected patients with heterogeneous emphysema. However, LVRS is a major surgical procedure with potential morbidity and mortality. Minimally invasive techniques are emerging to achieve lung volume reduction without open thoracotomy. Devices and techniques under study include one-way bronchial valves inserted via fiberoptic bronchoscopy to promote atelectasis in emphysematous lung, promotion of focal atelectasis and fibrosis by bronchoscopic injection of polymers into emphysematous regions of lung, bronchopulmonary fenestrations to enhance expiratory flow, and thoracoscopic plication or compression of emphysematous lung. The goal of all of these procedures is to replicate the benefit of LVRS without the trauma, risks, and extended recovery of open LVRS. Refinement and application of these techniques will allow patients with emphysema and their physicians and surgeons to choose from a number of viable options for lung volume reduction.

Key Words: bronchoscopy • COPD • emphysema • endobronchial valve • interventional bronchoscopy • lung volume reduction • lung volume reduction surgery • minimally invasive • thoracoscopy


   Introduction
TOP
 Abstract
 Introduction
Bronchoscopic Methods
 Thoracoscopic Techniques
 Conclusion
 References
 
Emphysema is characterized by destruction of alveolar walls distal to the terminal bronchioles.1 This process leads to enlargement of distal air spaces with development of emphysematous blebs, cysts, and bullae. Because capillary-rich alveolar walls are also destroyed in areas of emphysema, these enlarged air spaces have very high ventilation/perfusion (/) ratios creating physiologic dead space. Increased dead space ventilation reduces efficiency of breathing, resulting in increased work and impaired gas exchange.2

The destruction of alveolar walls also leads to decreased alveolar elastic recoil and decreased traction support of small airway lumens, leading to impaired exhalation. Reduced elastic recoil combined with expiratory airway collapse causes hyperinflation and air trapping in overly compliant emphysematous areas of lung.2 This hyperinflation can compress areas of more normal lung, leading to reduced ventilation in areas of lung that are well perfused. The resulting low / ratios in areas of compressed lung further impair gas exchange, leading to hypoxemia.3

Lung volume reduction surgery (LVRS) with surgical removal of hyperinflated poorly perfused areas of lung has been shown in numerous uncontrolled4 5 6 and controlled7 8 9 10 studies to benefit patients with emphysema. Functional, physiologic, and quality-of-life benefits have been demonstrated. These positive results have been validated by the recently reported National Emphysema Treatment Trial (NETT),11 which also demonstrated a survival benefit following LVRS for patients with upper-lobe heterogeneous emphysema and limited exercise capacity.

The encouraging results from the NETT11 confirm the value of removing hyperinflated, nonfunctioning areas of lung in patients with emphysema. Although the surgical morbidity and mortality data in the NETT study11 are acceptable, LVRS remains a major surgical procedure requiring general anesthesia and postoperative intensive care. LVRS is associated with potential complications including prolonged air leak, which can lead to lengthy hospitalization.12 13 The NETT study also identified a group of patients with very severe emphysema (FEV1 <= 20% and either diffusing capacity of the lung for carbon monoxide [DLCO] <= 20% or homogeneous emphysema) who had unacceptably high 30-day mortality (16%) from LVRS.14

The demonstrated benefits of LVRS and the rigors of surgical lung volume reduction have led investigators and medical equipment manufacturers to develop minimally invasive techniques to achieve lung volume reduction without open thoracotomy. Devices and techniques under study include bronchial occlusion devices inserted via fiberoptic bronchoscopy, promotion of focal atelectasis and fibrosis by bronchoscopic injection of polymers into emphysematous regions of lung, bronchopulmonary fenestrations to enhance expiratory flow, and thoracoscopic plication or compression of emphysematous lung. The goal of all of these procedures is to replicate the benefit of LVRS without the trauma, risks, and extended recovery of open LVRS.


   Bronchoscopic Methods
TOP
 Abstract
 Introduction
 Bronchoscopic Methods
Thoracoscopic Techniques
 Conclusion
 References
 
A one-way endobronchial valve system has been developed (Emphasys Endobronchial Valve; Emphasys Medical; Redwood City, CA) for the treatment of emphysema. The valve is designed for insertion into bronchi leading to emphysematous regions of lung. The intent is to promote atelectasis in emphysematous regions by preventing airflow into the bronchus while allowing outflow of air. The resulting atelectasis could reduce hyperinflation and dead space and allow expansion of previously compressed normal regions of lung, improving gas exchange. Emphysematous regions of lung may not always collapse following valve insertion due to collateral ventilation and/or severely reduced recoil in the lung distal to the valve. Even without atelectasis, the valve is intended to improve / ratio by shifting ventilation away from emphysematous regions of dead space to better perfused areas of lung. Furthermore, the one-way valve should inhibit dynamic hyperinflation of overly compliant emphysematous lung during exercise.

The Emphasys Endobronchial Valve consists of a silicone duckbill, one-way valve attached to a nitinol self-expanding stent retainer with silicone seals to occlude the bronchus around the valve (Fig 1 ). The valve is inserted into the intended segmental or subsegmental bronchus via a delivery housing device over a guidewire placed via a fiberoptic bronchoscope in a manner similar to stent insertion (Fig 2 ,3 ). The bronchoscope should be reinserted to confirm proper positioning before deployment of the valve from the delivery device. Position adjustments or removal (if necessary) can be accomplished with a biopsy forceps.



View larger version (126K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 1. Emphasys Endobronchial Valve consisting of a silicone duckbill, one-way valve attached to a nitinol self-expanding stent retainer with silicone seals to occlude the bronchus around the valve.

 


View larger version (103K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 2. Emphasys Endobronchial Valve compressed in housing device and advanced over guidewire.

 


View larger version (96K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 3. Emphasys Endobronchial Valve deployed by retracting housing and releasing the valve.

 
Animal studies were performed on sheep with the Emphasys Endobronchial Valve,15 in which 35 valves were inserted in eight sheep. At sacrifice, gross collapse distal to the valves was seen in 83% of the segments with valves inserted.

A phase I human study16 of valve placement in 10 patients with emphysema has been reported. Mean FEV1 was 0.725 L (range, 0.37 to 1.02 L; 19 to 46% predicted), with a 6-min walk of 340 m (range, 245 to 425 m). Four to 11 valves were inserted per patient under general anesthesia. Symptomatic improvement was noted in four patients. Spirometry and 6-min walk distances were unchanged, but DLCO increased significantly (7.45 ± 2 to 8.25 ± 2.6 mL/min/mm Hg at 1 month; 11% increase). Inpatient stay ranged from 1 to 8 days. Minor complications included exacerbations of COPD (three patients), hemoptysis, pneumothorax, and left lower lobe pneumonia (one each). This initial study established that the valve could be safely placed in patients with emphysema.

A subsequent pilot study17 with a second-generation Emphasys Endobronchial Valve has been recently published. Eight patients had severe emphysema that was heterogeneous on CT and / scan with severe dyspnea on exertion despite pulmonary rehabilitation. Baseline median FEV1 was 0.79 L (23% predicted; range, 18.4 to 35.7% predicted), residual volume (RV) was 6.82 L (272.8% predicted; range, 219 to 321% predicted), and DLCO was 35.6% predicted (range, 24.8 to 51.4% predicted). Twenty-five endobronchial valves were inserted over a guidewire placed bronchoscopically under general IV anesthesia with pressure-limited ventilation. Valves were inserted unilaterally in all segmental bronchi leading to the upper lobe most affected by emphysema in each patient. Median procedure time was 1 h (range 0.5 to 2.5 h). All patients were extubated immediately following the procedure.

Four of eight patients showed radiographic signs of volume reduction. These four patients showed the greatest improvement in pulmonary function test results. However, improvements in FEV1 and DLCO capacity were seen in some patients without collapse, suggesting improved / ratios following valve insertion. For the entire group, significant improvements in median FEV1 (0.79 to 1.06 L; p = 0.025) and median DLCO (3.05 to 3.92 mL/min/mm Hg; p = 0.017) were seen at 4 weeks. There were no significant changes in RV, shuttle distance, or quality-of-life scores. Ipsilateral pneumothoraces developed in two patients at 2 days and 4 weeks after the procedure, respectively. Three patients had exacerbations of COPD (two patients at 7 days and one patient at 30 days). A randomized controlled study of the Emphasys Endobronchial Valve in the United States recently obtained US Food and Drug Administration approval.

Another endobronchial valve for lung volume reduction has been developed, the Spiration Intra-Bronchial Valve (Spiration; Redmond, WA). The Spiration Intra-Bronchial Valve is an umbrella-shaped device consisting of a polyurethane membrane on a nitinol frame (Fig 4 ). The valve is placed in the bronchus via a delivery catheter inserted directly through the working channel of a fiberoptic bronchoscope (Fig 5 ). The valves are produced in various sizes.



View larger version (81K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 4. Spiration Intra-Bronchial Valve consisting of an umbrella-shaped polyurethane membrane on a nitinol frame.

 


View larger version (114K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 5. Spiration Intra-Bronchial Valve and delivery system shown folded (top) allowing passage through the working channel of a bronchoscope and deployed (bottom).

 
In an animal study, 21 valves were inserted into the upper lobes of five healthy swine. After 4 to 6 days, bronchoscopy and fluoroscopy confirmed proper positioning of the valves.18 One valve in each of the four swine was easily removed and replaced bronchoscopically.19 No complications were observed. At thoracotomy 4 to 6 days after valve insertion, visual confirmation of volume reduction was observed.18 19

The umbrella-shaped valve with the convex side distally is designed to allow mucus and air to escape from the targeted bronchus while preventing air from entering the bronchus. The intent is to limit ventilation to emphysematous regions of lung, allowing better ventilation of healthier regions, while allowing mucus to escape from the treated region to avoid postobstructive pneumonia. Human trials are pending.

Bronchoscopic occlusion of bronchi to treat bronchopleural fistulae has been reported. Twenty-three patients with emphysema and bronchopleural fistula were treated with endoscopic Watanabe spigots (EWSs; Fig 6 ) [ Novatech; Plan deGrasse, France] during 2000 and 2001.20 Ninety-one spigots were inserted in 23 patients. Upper-lobe collapse was seen in two patients who had their whole upper lobe occluded. Complications reported were pneumonia (n = 2) and dyspnea (n = 1). A patient with emphysema and giant bullae was treated with the EWS.21 The bullae became larger following insertion of the EWS, presumably due to collateral ventilation with impaired exhalation from the occluded bronchus. One-way valve devices described previously avoid this complication.



View larger version (117K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 6. EWS consisting of 5 mm, 6 mm, and 7 mm in diameter silicon plugs.

 
Based on the favorable results from LVRS, Ingenito et al22 theorized that collapse of emphysematous regions of lung via fiberoptic methods consisting of surfactant washout and fibrin-based glue instillation could achieve results similar to LVRS. This hypothesis was tested on 12 sheep with emphysema induced by four weekly papain inhalations. The nebulized papain produced histologically confirmed emphysema. Total lung capacity (TLC), RV, and RV/TLC increased in all animals. Lung compliance increased as well. After intubation and ventilation with 100% oxygen, selected lung subsegments were lavaged with "antisurfactant" solution via a multichannel, balloon-tipped catheter inserted through a fiberoptic bronchoscope. Following suction, a fibrin-based sealant was injected into the selected subsegment with bronchoscopic confirmation of effective sealing. Animals treated with this method of bronchoscopic volume reduction had significant reductions in TLC (64% return to baseline) and RV (72% return to baseline), with decreased compliance. Visual atelectasis was apparent at autopsy. These results were similar to those in a group of sheep treated with surgical lung volume reduction. Sterile lung abscesses developed in two of four of the sheep treated with bronchoscopic volume reduction. Only 11 of 20 subsegments treated exhibited sustained collapse.

A newer technique of bronchoscopic lung volume reduction has been recently reported by Ingenito et al.23 Six sheep in this study had papain-induced emphysema that produced increases in TLC, functional residual capacity (FRC), RV, and airway resistance with reduction in elastic recoil and DLCO. Six lung segments in each sheep had fiberoptic bronchoscopy with instillation of an enzymatic solution of trypsin to remove epithelial cells in the targeted region. This was followed by instillation of fibrin hydrogel and thrombin through a bronchoscopically placed catheter to promote fibroblast attachment and collagen synthesis. The intent was to remodel hyperinflated emphysematous lung segments into contracted scar tissue.

The bronchoscopic lung volume reduction procedure was well tolerated without hypoxemia or bronchospasm. Three weeks after bronchoscopic volume reduction, there were significant reductions in TLC (3.63 to 3.01 L, p = 0.02), FRC (2.04 to 1.66 L, p = 0.05), and RV (1.43 to 0.63 L, p = 0.002). Recoil pressure increased. These improvements in lung function were maintained at 9 weeks. DLCO improved following bronchoscopic volume reduction, but not back to levels measured before papain installation. Serial CT scans and autopsy at 9 weeks after bronchoscopic lung volume reduction confirmed volume reduction and fibroblastic scar formation with collagen deposition in the treated areas. There were no lung abscesses with this method.

Lausberg et al24 recently reported a method of radiofrequency-induced fenestrations in segmental bronchi to enhance expiratory airflow in emphysematous lungs. Twelve explanted emphysematous lungs removed during lung transplantation were studied in a ventilation chamber ex vivo. Three to five fenestrations were made in segmental or subsegmental bronchi adjacent to lung parenchyma with a radiofrequency catheter (Exhale RF Probe; Bronchus Technologies; Mountain View, CA) inserted via a fiberoptic bronchoscope. Patency of the bronchopulmonary fenestrations was maintained with uncovered coronary stents (3 mm in diameter, 15 mm in length). Mean FEV1 measured in the experimental pressurized ventilation chamber increased from 245 to 447 mL (83% increase, p < 0.001) following creation of the stented fenestration. In vivo animal studies of this procedure are underway.


   Thoracoscopic Techniques
TOP
 Abstract
 Introduction
 Bronchoscopic Methods
 Thoracoscopic Techniques
Conclusion
 References
 
Prolonged air leaks remain a common complication following LVRS.12 13 25 26 Most surgeons use bovine pericardial strips to buttress the staple line during LVRS.12 26 27 Another method reported to minimize postoperative air leaks involved thoracoscopic lung plication rather than standard resection for LVRS.

Swanson et al28 reported a method of plication involving grasping the involved portion of lung with a ring forceps, folding the tissue with a plication clamp, followed by stapling across the folded lung through four layers of visceral pleura. Thirty-two patients with emphysema (mean FEV1, 0.68 L; 22% predicted) were operated on in 50 procedures (14 unilateral and 18 bilateral). Two procedures (4%) were converted to open thoracotomy for air leak. Four other procedures (9%) were associated with prolonged air leaks (> 7 days). FEV1 increased by a mean of 29%, with 78% of patients showing an increase in FEV1.

Iwasaki et al29 described another method of thoracoscopic plication involving stapling across the apex of the lung, folding the lung at the staple line, and then restapling across the fold, holding the lung in a folded position. Twenty patients with emphysema had unilateral thoracoscopic lung reduction by this method of fold plication. Postoperative air leak lasted 0 to 5 days (1.7 days). FEV1 increased from 24.2 to 42.4% predicted with improvement in dyspnea in all patients. One patient had a spontaneous pneumothorax on day 7.

Air leaks have not been eliminated following LVRS with either bovine pericardium12 13 25 26 27 or lung plication.28 29 Use of a novel, vacuum-assisted, implantable elastomer device for lung reduction has been reported in animals with emphysema.30 Emphysema was induced in rabbits with nebulized elastase three times over 4 weeks. Development of emphysema was confirmed histologically and by increases in FRC and compliance. Twenty rabbits with emphysema had median sternotomy. Ten of the rabbits underwent lung reduction performed by applying suction to an elastomer sleeve in contact with the emphysematous lung. Lung tissue was drawn into the sleeve and held in place with a proximal purse string suture and distal sutures through the device and the reduced lung. There were no air leaks in any of the animals after the operation. FRC and compliance both decreased in the animals who underwent the lung reduction procedure, and did not change in the animals who underwent sternotomy without lung reduction.30 Fluorescent microsphere injections in the treated rabbits demonstrated decreased blood flow to the reduced lung tissue as well.31

Similar results with vacuum-assisted lung reduction were obtained in a study of dogs with papain-induced emphysema. Emphysema was confirmed by significant increases in TLC, FRC, and RV, with significant reduction in all three measurements at 1 month and 6 months following lung reduction.32 There were no air leak complications. Extreme reduction in blood flow to the reduced areas of lung was demonstrated with fluorescent microsphere injections.33

Spiration, Inc. (Redmond, WA) began a US Food and Drug Administration-approved clinical trial of vacuum-assisted lung reduction (VALR) in April 2002.34 The current elastomer sleeve under study is deployed with a button-activated introducer using gentle vacuum pressure to draw lung tissue into the sleeve (Fig 7 ). The sleeve applies radial compression via a band to the proximal lung tissue in the sleeve, sealing the compressed lung. Sutures are placed through the sleeve and the proximal compressed lung (Fig 8 ). The distal compressed lung and sleeve are removed, leaving a short cylinder of compressed lung on the surface.



View larger version (102K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 7. Spiration VALR elastomer sleeve using gentle vacuum pressure to draw lung tissue into the sleeve.

 


View larger version (133K):
[in this window]
[in a new window]
[Download PPT slide]
  		Figure 8. Remaining short cylinder of compressed lung and proximal portion of Spiration VALR elastomer sleeve following removal of distal compressed lung and sleeve.

 
The VALR device was recently tested intraoperatively on six patients immediately prior to lobectomy for lung cancer. In each case, 20 to 30% of the affected lobe was compressed with a single device applied to a portion of the lobe not involved with cancer. Compressed lung inside the distal portion of the sleeve was resected after lobectomy. Lobe reinflation following resection showed no air leaks or tissue trauma.35 Development of a thoracoscopic VALR system is underway (S. Springmeyer; personal communication; October 2003).


   Conclusion
TOP
 Abstract
 Introduction
 Bronchoscopic Methods
 Thoracoscopic Techniques
 Conclusion
References
 
The value of LVRS in selected patients has been demonstrated in a large randomized controlled trial.11 Efforts are underway to achieve similar beneficial results with minimally invasive techniques. Further study is needed to determine the optimal minimally invasive method for lung volume reduction and to compare the results of minimally invasive techniques directly with surgical lung volume reduction. Bronchoscopic lung volume reduction may permit lung reduction in patients with previous thoracotomy or pleural adhesions who would currently be excluded from surgical lung volume reduction. Bronchoscopic valve insertion may be used to predict outcomes of lung volume reduction before contemplating surgery.

The preclinical and early clinical trials with minimally invasive lung reduction are promising. With further careful study, the risk/benefit profile of these procedures will be determined, allowing patients with emphysema and their physicians to choose among a number of viable options for lung volume reduction.


   Footnotes
 
Abbreviations: DLCO = diffusing capacity of the lung for carbon monoxide; EWS = endoscopic Watanabe spigot; FRC = functional residual capacity; LVRS = lung volume reduction surgery; NETT = National Emphysema Treatment Trial; RV = residual volume; TLC = total lung capacity; VALR = vacuum-assisted lung reduction; / = ventilation/perfusion

Dr. Maxfield will be an investigator in the Endobronchial Valve for Emphysema Palliation Trial (pending institutional review board approval) sponsored by Emphasys Medical, Inc., Redwood City, CA.

Received for publication May 30, 2003. Accepted for publication August 6, 2003.


   References
TOP
 Abstract
 Introduction
 Bronchoscopic Methods
 Thoracoscopic Techniques
 Conclusion
 References
 

  1. Snider, G, Thurlbeck, W, Bengali, Z (1985) The definition of emphysema: report of a National Heart, Lung, and Blood Institute Division of Lung Diseases workshop. Am Rev Respir Dis 132,182-185[ISI][Medline]
  2. West, JB Pulmonary pathophysiology: the essentials. 5th ed. 1998,49-67 Lippincott, Williams & Wilkins. Baltimore, MD:
  3. Snider, GL Reduction pneumoplasty for giant bullous emphysema: implications for surgical treatment of nonbullous emphysema. Chest 1996;109,540-548[Abstract/Free Full Text]
  4. Yusen, RD, Lefrak, SS, Gierada, DS, et al A prospective evaluation of lung volume reduction surgery in 200 consecutive patients. Chest 2003;123,1026-1037[Abstract/Free Full Text]
  5. Gelb, AF, McKenna, RJ, Jr, Brenner, M, et al Lung function 5 yr after lung volume reduction surgery for emphysema. Am J Respir Crit Care Med 2001;163,1562-1566[Abstract/Free Full Text]
  6. Sciurba, FC, Rogers, RM, Keenan, RJ, et al Improvement in pulmonary function and elastic recoil after lung-reduction surgery for diffuse emphysema. N Engl J Med 1996;334,1095-1099[Abstract/Free Full Text]
  7. Criner, GJ, Cordova, SC, Furukawa, S, et al Prospective randomized trial comparing bilateral lung volume reduction surgery to pulmonary rehabilitation in severe chronic obstructive pulmonary disease. Am J Respir Crit Care Med 1999;160,2021-2027
  8. Geddes, D, Davies, M, Koyama, H, et al Effect of lung-volume-reduction surgery in patients with severe emphysema. N Engl J Med 2000;343,239-245[Abstract/Free Full Text]
  9. Goodnight-White, S, Jones, JW, Baaklini, WA, et al Prospective, randomized, controlled trial comparing bilateral lung volume reduction surgery (LVRS) to medical therapy alone in patients with emphysema [abstract]. Chest 2000;118(suppl),102S
  10. Pompeo, E, Marino, M, Nofroni, I, et al Reduction pneumoplasty versus respiratory rehabilitation in severe emphysema: a randomized study. Ann Thorac Surg 2000;70,948-954[Abstract/Free Full Text]
  11. National Emphysema Treatment Trial Research Group.. A randomized trial comparing lung-volume-reduction surgery with medical therapy for severe emphysema. N Engl J Med 2003;348,2059-2073[Abstract/Free Full Text]
  12. Hazelrigg, SR, Boley, TM, Naunheim, KS, et al Effect of bovine pericardial strips on air leak after stapled pulmonary resection. Ann Thorac Surg 1997;63,1573-1575[Abstract/Free Full Text]
  13. McKenna, RJ, Jr, Fischel, RJ, Brenner, M, et al Use of the Heimlich valve to shorten hospital stay after lung reduction surgery for emphysema. Ann Thorac Surg 1996;61,1115-1117[Abstract/Free Full Text]
  14. National Emphysema Treatment Trial Research Group.. Patients at high risk of death after lung-volume-reduction surgery. N Engl J Med 2001;345,1075-1083[Abstract/Free Full Text]
  15. Fann, JI, Berry, GJ, Burdon, TA Lung volume reduction using bronchoscopically deployed endobronchial valve devices [abstract]. Am J Respir Crit Care Med 2003;167(suppl),A532
  16. Snell, GI, Holsworth, LC, Borrill, ZL, et al Bronchoscopic lung volume reduction (BLVR) using bronchial prostheses: a pilot safety and efficacy study [abstract]. Chest 2002;122(suppl),193S
  17. Toma, TP, Hopkinson, NS, Hillier, J, et al Bronchoscopic volume reduction with valve implants in patients with severe emphysema. Lancet 2003;361,931-933[CrossRef][ISI][Medline]
  18. Gonzalez, X, Dillard, DH, DeVore, LJ, et al Evaluation of bronchoscopic and surgical lung volume reduction as single or combined procedures [abstract]. Chest 2002;122(suppl),192S-193S
  19. Dillard DH, Gonzalez X, DeVore LJ, et al. Evaluation of a novel intra-bronchial valve to produce lung volume reduction. Presented at: World Congress of Bronchology, June 16–19, 2002, Boston, MA. Available at: http://www.spirationinc.com/downloads/evaluation_novel_ibv.pdf. Accessed January 12, 2004
  20. Toma, TP, Matsuo, K, Tamaoki, A, et al Endoscopic bronchial occlusion with spigots in patients with emphysema [abstract]. Am J Respir Crit Care Med 2002;165(suppl),B9
  21. Watanabe Y. LVRS with WBA. Presented at: World Congress of Bronchology, June 16–19, 2002, Boston, MA
  22. Ingenito, EP, Reilly, JJ, Mentzer, SJ, et al Bronchoscopic volume reduction: a safe and effective alternative to surgical therapy for emphysema. Am J Respir Crit Care Med 2001;164,295-301[Abstract/Free Full Text]
  23. Ingenito, EP, Berger, RL, Henderson, AC, et al Bronchoscopic lung volume reduction using tissue engineering principles. Am J Respir Crit Care Med 2003;167,771-778[Abstract/Free Full Text]
  24. Lausberg, HF, Chino, K, Patterson, GA, et al Bronchial fenestration improves expiratory flow in emphysematous human lungs. Ann Thorac Surg 2003;75,393-397[Abstract/Free Full Text]
  25. Fischel, RJ, McKenna, RJ, Jr Bovine pericardium versus bovine collagen to buttress staples for lung reduction operations. Ann Thorac Surg 1998;65,217-219[Abstract/Free Full Text]
  26. Daniel, TM, Chan, BB, Bhaskar, V, et al Lung volume reduction surgery: case selection, operative technique, and clinical results. Ann Surg 1996;223,526-531[CrossRef][ISI][Medline]
  27. Cooper, JD, Trulock, EP, Triantafillou, AN, et al Bilateral pneumectomy (volume reduction) for chronic obstructive pulmonary disease. J Thorac Cardiovasc Surg 1995;109,106-116[Abstract/Free Full Text]
  28. Swanson, SJ, Mentzer, SJ, DeCamp, MM, Jr, et al No-cut thoracoscopic lung plication: a new technique for lung volume reduction surgery. J Am Coll Surg 1997;185,25-32[CrossRef][ISI][Medline]
  29. Iwasaki, M, Nishiumi, N, Kaga, K, et al Application of the fold plication method for unilateral lung volume reduction in pulmonary emphysema. Ann Thorac Surg 1999;67,815-817[Abstract/Free Full Text]
  30. Brenner, M, Gonzalez, X, Jones, B, et al Effects of a novel implantable elastomer device for lung volume reduction surgery in a rabbit model of elastase-induced emphysema. Chest 2002;121,201-209[Abstract/Free Full Text]
  31. Brenner, M, Sirokman, W, Jones, B, et al Pulmonary blood flow changes produced by a novel implantable device used for LVRS in a rabbit model of emphysema [abstract]. Am J Respir Crit Care Med 2002;165(suppl),B11
  32. Mink, S, Gonzalez, X, Duke, K, et al Six-month evaluation of a novel implantable device for lung volume reduction surgery in a canine model of upper lobe emphysema [abstract]. Am J Respir Crit Care Med 2002;165(suppl),B12
  33. Mink, SN, Sirokman, WA, Gonzalez, X, et al A novel lung volume reduction device restricts pulmonary blood flow in a canine model of emphysema [abstract]. Chest 2002;122(suppl),216S
  34. Spiration announces first human use of VALR device during lung surgery [press release]. Redmond, WA: Spiration, 2002. Available at: http://www.spirationinc.com/downloads/valr_1st_patient_release.pdf. Accessed January 12, 2004
  35. Vallieres, E, Gonzalez, X, Pedersen, KM, et al Use of a novel implantable device that compresses and allows resection of human lung tissue without leak complications [abstract]. Am J Respir Crit Care Med 2003;167(suppl),A537



This article has been cited by other articles:


Home page
 ChestHome page
D. Stolz, V. Pollak, P. N. Chhajed, C. Gysin, E. Pflimlin, and M. Tamm
A Randomized, Placebo-Controlled Trial of Bronchodilators for Bronchoscopy in Patients With COPD
Chest, March 1, 2007; 131(3): 765 - 772.
[Abstract] [Full Text] [PDF]

Home page
 RadioGraphicsHome page
J.-M. Kuhnigk, V. Dicken, S. Zidowitz, L. Bornemann, B. Kuemmerlen, S. Krass, H.-O. Peitgen, S. Yuval, H.-H. Jend, W. S. Rau, et al.
Informatics in Radiology (infoRAD): New Tools for Computer Assistance in Thoracic CT. Part 1. Functional Analysis of Lungs, Lung Lobes, and Bronchopulmonary Segments
RadioGraphics, March 1, 2005; 25(2): 525 - 536.
[Abstract] [Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF) Free
Right arrow Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when eLetters are posted
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Article Archive
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via ISI Web of Science (5)
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Maxfield, R. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Maxfield, R. A.

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS