- Email: [email protected]
Thoracoscopy
Thoracoscopy* Window to the Pleural Space Henri G. Colt, MD, FCCP
Thoracoscopy has provided chest physicians and surgeons with an opportunity to rethink their approach to patients with pleural and pulmonary disease. In this brief review, several methods pertaining to videothoracoscopic procedures are described, followed by a summary of the major indications for this procedure. The question of whether a thoracoscopic approach to diagnosis or treatment could replace more conventional approaches is addressed for several disease processes. Finally, a few thoughts about future directions of this emerging technology are shared. (CHEST 1999; 116:1409 –1415) Key words: pleural disease; technology; thoracoscopy; video-assisted thoracic surgery Abbreviation: SVHS 5 Super VHS
endoscopic surgical techniques, regardE volving less of whether skin incisions are required, continue to revolutionize patient care. Possibly the day will emerge when a group of endoscopic surgical specialists is capable of performing a variety of procedures crossing over several organ systems. After all, some might say a scope is always a scope. It is not surprising that our sense of social responsibilities as well as medical curiosity incite us to seek new and potentially less invasive ways of performing diagnostic and therapeutic chest procedures. The endoscopic surgery revolution is a direct result of such innovations. For readers wondering how these emerging technologies and novel procedures will safely find their way into mainstream medical and surgical practice, rest assured: procedural expertise will be rapidly acquired once we introduce new core curriculums: I predict, for example, that training capabilities will soon be enhanced by the incorporation of virtual reality simulators. The purpose of this supplement, however, is not to focus only on the future, but to summarize the present role of emerging technologies in pulmonary practice. In this regard, the inclusion of thoracoscopy in such a supplement is indeed welcome. Although endoscopic visualization of the contents of the pleural space has been performed in Europe since Jacobaeus, the procedure was seldom performed in the United States. For reasons that are still unclear, *From the Division of Pulmonary and Critical Care Medicine, University of California, San Diego, CA. Correspondence to: Henri G. Colt, MD, FCCP, Associate Professor of Medicine, Chief, Interventional Pulmonology, UCSD Medical Center, La Jolla, CA 92037; e-mail: [email protected]
thoracoscopy had fallen into near total oblivion in this country during the last 50 years. During this decade, however, thoracoscopy found its way back into mainstream chest medicine and surgery. This is due, in part, to the impact of laparoscopic surgery on general surgical practice, prompting many thoracic surgeons to modify proven open surgical techniques so that therapeutic procedures could be performed through smaller incisions using specially designed instruments and videotechnology.1 To their credit, thoracic surgical societies have done a remarkable job of describing thoracoscopic surgical techniques, publishing prospective and retrospective reports, introducing training guidelines, and evaluating novel surgical techniques so that video-assisted thoracic surgery could find a proper place among surgical management strategies. The thoracoscopic window to the pleura was also opened by a handful of pulmonologists who pushed the envelope, so to speak, in their efforts to efficiently and effectively diagnose patients with pleural disorders or manage patients with incurable malignant pleural disease. Techniques of thoracoscopic pleural biopsy, fluid drainage, and pleurodesis are now recognized components of the interventional pulmonologist’s practice. Sessions about thoracoscopy and its role in the management of patients with simple and complex pleural diseases are included in today’s postgraduate courses and pulmonary society meetings. Undeniably, the bridges being built between pioneers in “interventional pulmonology” and their thoracic surgery colleagues will result in greater collaborative efforts among present and future generations of health-care providers. CHEST / 116 / 5 / NOVEMBER, 1999
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In the following paragraphs, the technology and methods pertaining to videothoracoscopic procedures are reviewed. A brief description of the major indications for these procedures follows, accompanied by comments on whether a thoracoscopic approach to diagnosis or treatment could replace more conventional approaches. Finally, the closing paragraphs are devoted to a discussion of the potential limitations of thoracoscopy and thoughts about future directions. It goes without saying that I beg the reader’s indulgence for not providing herein an inclusive review of current knowledge and practice of thoracoscopic procedures: a simple MEDLINE search (English language, years from 1990 to 1998) using only thoracoscopy as a key word yielded 1,035 citations. Because of space limitations, I have intentionally limited references to a few selected review articles and original research published in various international journals, representing a broad scope of thoracoscopic practice in both the chest physician’s and chest surgeon’s literature, and for the most part, published since 1995. To the many colleagues and fellow investigators who have published articles in these areas, but whose names I have not cited, your forgiveness is appreciated.
Technology and Instrumentation For many years, visualization of a closed space such as the pleural cavity was possible through a rigid Hopkins lens telescope attached to a cold light source. Only the operator was able to visualize the contents of the pleural space, although occasionally, a single assistant could watch through a “teaching head” attached to the eyepiece of the telescope. Teaching heads reduced the amount of light transmitted through the telescope, and were also extremely expensive, costing several thousand dollars. In addition, the operator could use only one hand to manipulate instruments because the other hand held the telescope. The same was true for the assistant who held the teaching head. Thoracoscopic instruments were designed to facilitate operative procedures. Forceps, graspers, lung manipulators, cautery and cutting devices, suction/ irrigation instruments, and a variety of disposable and reusable pleural trocars and cannulas are currently available. Many of the same instruments used in open thoracic surgery can be used in thoracoscopic surgery; it is really the development of the endoscopic stapling device that expanded the scope of thoracoscopic practice. Of course, the introduction of videotechnology into medical practice also changed our acceptance of 1410
thoracoscopic procedures. Not only have optics considerably improved—telescopes used today have greater depth of field, magnification, and arc of vision— but now multiple assistants and observers can watch an entire procedure. Visualization of the contents of the pleural cavity is facilitated by a videocamera that is attached to the eyepiece of the rigid telescope. The size and quality of these cameras has considerably improved in recent years, and the addition of video makes viewing, documentation, and assisting during procedures far easier than in the days of direct visualization. Newer telescopes magnify the subject being visualized (usually about 43 for a 7-mm rigid telescope), and the increased availability of couplers of varying sizes allow greater depth of field and increased field of vision without distortion to enhance visibility. Image size on the video monitor is affected by the aperture of the telescope, coupler size, and camera sensor size. The larger the coupler, the greater the magnification of the image. Unfortunately, this also decreases the amount of light being transmitted into the already large and relatively dark pleural cavity. Light sources today, however, are able to autoregulate the amount of light being transmitted through fiberoptic light cables, although many operators prefer to manually adjust these light controls. Images are usually recorded using a VHS or Super VHS (SVHS) video recorder/player. It is fascinating that most procedure suites and operating rooms today are stocked with expensive carts and highgrade equipment that is rarely, if ever, used to its full capacity. In fact, for routine patient care purposes, a single-chip videocamera, a basic single standard medical-grade monitor or other video display, and simple VHS videorecorder amply suffice. With a single-chip camera, a segmented multicolor filter is often placed over a single sensor. Although detail is reduced, most physicians are unable to tell the difference compared with a far more expensive three-chip camera. For thoracoscopists who require quality images for preparation of educational materials such as CDROMs, however, higher-grade equipment is often desirable. Not surprisingly, the costs associated with the acquisition of high-grade equipment can be excessive. A three-chip camera, for example, may cost as much as $12,000. In addition, these cameras are bulkier, heavier, and less comfortable to handle. A three-chip camera splits light into the three separate colors (red, green, and blue, or RGB). The video signals are then distributed as separate red, green, and blue signals with separate synchronizing pulses, as a combined composite video signal, or as two separate signals (known as luminance and chrominance, or Y/C). Global Theme Issue: Emerging Technology in Clinical Medicine
The image is recorded onto a typical VHS recorder (with a line resolution of only 250 lines), or an SVHS video recorder (with a line resolution of . 400 lines). It is noteworthy that the conventional television screen has a line resolution of only 320 vertical lines, although more advanced video displays have a resolution of about 560 lines. By recording master images on SVHS rather than VHS, dubs (copies) will be of greater quality. The costs of a good SVHS deck is approximately $1,200 (about $2,500 for a medicalgrade deck), compared with less than $400 for a VHS deck; the SVHS videotapes used daily are also more costly than VHS tapes. SVHS tapes cannot be viewed on VHS decks (which are the decks most people have at home next to their television sets), so subsequent editing and dubbing onto VHS is mandatory. Of course, with higher-quality television sets and the advent of the digital versatile disc, or DVD, SVHS inputs may soon become commonplace for in-home use. Thoracoscopic exploration, however, is unlikely to undergo a radical change in the immediate future. Certain advances are necessary to improve documentation sources and to keep up with changes occurring in the world of communication, such as transmission over the World Wide Web. Eventually, images will be captured and recorded digitally before being transferred to CD-ROM for editing and storage. These changes will not be required, however, for the majority of thoracoscopists using videotechnology for simple observation and documentation. Eventually, smaller telescopes with excellent illumination and visualization capabilities may be used for microthoracoscopy; a thoracoscope with distal charge-coupled device will be developed2; and an enhanced flexible fiberoptic videothoracoscope may find its way into the same day procedure suite a` la flexible fiberoptic bronchoscopy.
Clinical Applications Thoracoscopy is usually performed through one or several small, , 2-cm skin incisions made along the intercostal spaces. Patients are placed in the lateral decubitus position, involved side up, although some procedures, such as a thoracic sympathectomy, are performed with patients in the supine position. Pleural trocars can also be safely placed in the axilla, so that axillary thoracoscopy can potentially precede an axillary thoracotomy. IV sedation and local anesthesia are administered using techniques similar to those employed when making a chest tube insertion incision. Many operators prefer general anesthesia with single- or double-lumen endotracheal intubation performed in an operating suite. Certainly, the
operating room is the accepted procedural area for diagnostic and therapeutic procedures such as lung biopsies, decortication, or cardiovascular interventions. Many procedures limited to removal of pleural fluid, visualization, and biopsy of parietal pleura can be performed through a single skin incision made in approximately the fifth to seventh intercostal space along the lateral chest wall of the involved hemithorax. When a 5- to 10-mm pleural trocar and cannula are inserted through the incision, the parietal pleura, diaphragm, and lung are well visualized. Pleural fluid is evacuated and parietal pleural biopsy specimens are obtained from both normal- and abnormalappearing areas. A chest tube is placed through the incision site and connected to a suction device, and the lung is gently reexpanded. Because the duration of chest tube drainage can be only a few hours, many patients are discharged the same day. In years past, this type of procedure was commonly referred to as pleuroscopy. Today, because of the very minimally invasive nature of the procedure, it has become known as “medical thoracoscopy.”3 Complications such as bleeding (from parietal pleural biopsy), lung perforation (during trocar insertion), or infection (from inadvertently using nonsterile techniques) are extremely rare.4 Advanced diagnostic and therapeutic procedures are usually performed in an operating suite. Multiple incisions allow the introduction of biopsy forceps, endoscopic scissors, electrocautery, suction-irrigation instruments, and grasping forceps to allow greater mobilization of the lung, removal of fibrin deposits or blood clots, and sectioning of adhesions that prevent complete inspection of the pleural space and mediastinum. Sometimes these adhesions also inhibit complete lung expansion; they may also maintain patency of visceral pleural tears in patients with spontaneous or secondary pneumothorax. In patients with complex pleural effusions, suspected underlying trapped lung requiring an attempt at reexpansion using positive pressure ventilation, empyema, and multiloculated pleural effusions from infection or malignancy, the pleural space and mediastinum can be safely explored using general anesthesia and multiple access sites. Although comparative studies have not been performed, it is possible that complication rates may be increased in this setting because of the increased morbidity of patients undergoing these procedures, the use of general anesthesia, and the invasive scope of procedures being performed. Pleural Effusion of Unknown Etiology Algorithms for investigating pleural effusion of unknown etiology typically begin with thoracentesis. CHEST / 116 / 5 / NOVEMBER, 1999
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Because cytologic examination is diagnostic in only 60 to 80% of patients with metastatic pleural involvement and in , 20% of patients with mesotheliomas, however, thoracoscopic parietal pleural examination and biopsy present an exciting opportunity to achieve earlier diagnosis.5 Most experts agree that when the initial evaluation of a pleural effusion is nondiagnostic, especially when neoplastic disease is suspected, thoracoscopic exploration and parietal pleural biopsy should be considered.6 The diagnostic accuracy of thoracoscopy is between 90 and 100%, compared with an approximate sensitivity of 44% for closed needle pleural biopsy and 62% for fluid cytology; false negatives occur most frequently in cases of early malignant mesothelioma. If the patient has a malignancy and negative cytology on thoracentesis, thoracoscopy is preferred over closed needle pleural biopsy because it will establish the diagnosis in . 90% of cases. Tuberculous Pleurisy The greater debate is whether thoracoscopy is warranted if tuberculosis is high on the list of differential diagnoses. In exudative pleural effusions due to tuberculosis, the diagnostic yield of a closed needle biopsy is 70 to 90%. Thoracoscopy is usually unnecessary, therefore, to establish the diagnosis of a tuberculous effusion. A combined yield of only 6% for thoracoscopy preceded by negative thoracentesis and closed needle pleural biopsy has been reported. Thoracoscopy may be beneficial in difficult diagnostic situations, however, when lysis of adhesions is necessary, or when larger amounts of tissue are warranted to assure diagnosis when drug resistance is suspected. Malignant Mesothelioma Although malignant mesothelioma may be suspected based on a history of asbestos exposure, symptoms, radiographic findings of pleural fluid, thickening, absence of contralateral shift of the mediastinum, and clinical course, diagnostic confirmation is often difficult. Pleural fluid cytology ranges from 4 to 77%, and representative specimens from closed needle biopsy are rarely of sufficient size and number to allow the full battery of immunohistochemical stains and electron microscopic examination for definitive diagnosis.7 Even with thoracoscopy, the accuracy of diagnosing mesothelioma may suffer because of inadequate visualization due to extensive adhesions and the inherent difficulties in pathologic identification of this tumor.8 Thoracoscopy allows removal of large, full-thickness specimens from several involved areas, making it potentially preferable to open pleural biopsy by minitho1412
racotomy, and most certainly preferable to lateral thoracotomy. Symphysis between visceral and parietal pleural surfaces and the absence of pleural fluid can make these procedures technically challenging. For patients not considering intrapleural chemotherapy or surgical resection, pleurodesis can be performed at the time of diagnostic thoracoscopy in order to prevent fluid reaccumulation and to delay the onset of lifethreatening dyspnea. Although tumor growth through thoracoscopic incision sites has been described,9 it is probably less frequent than reported. Prevention is possible by treating the area surrounding the incision sites with radiation. Patients should be warned that such prophylactic radiation could potentially make them ineligible for some clinical trials. Malignant Pleural Effusions In addition to diagnosis, an important indication for thoracoscopy in patients with malignant pleural effusions is pleurodesis.10 Complete evacuation of pleural fluid, maximization of lung expandability by removing adhesions, and pleurodesis by talc insufflation (also known as talc poudrage) results in shortand long-term success rates of . 90%.11 Distribution of sterile, asbestos-free, US Pharmacopeia–approved talc powder on all pleural surfaces is confirmed by thoracoscopic visualization. Following pleurodesis, low-grade fevers should be expected in up to 30% of patients, and hospitalization duration averages 4.8 days. Pleurodesis can also be achieved by pleurectomy using standard dissection techniques or hydrodissection.12 Because survival of patients with advanced pleural carcinomatosis is often short, the risks and benefits of thoracoscopic pleurodesis must be carefully weighed against those of repeat thoracentesis, tube thoracostomy, or bedside pleurodesis through an indwelling chest tube. Recurrent Pleural Effusions of Benign Etiology Recurrent pleural effusions of benign etiology are frequently caused by heart failure, cardiac surgery, nephrotic syndrome, connective tissue diseases, and other inflammatory disorders. Thoracoscopy may be warranted when recurrent effusions cause symptoms and are not controlled by repeated large-volume thoracentesis. Usually, pleural biopsy specimens are obtained to exclude infectious or neoplastic etiologies, and pleurodesis is performed. Results are usually excellent when talc is used, with success rates varying from to 65 to . 90%. Lung Cancer Most pleural effusions associated with lung cancer result from direct carcinomatous involvement of the Global Theme Issue: Emerging Technology in Clinical Medicine
pleura. Even patients in whom cytologic examination of pleural fluid is negative are often found on thoracotomy to have unresectable lesions. Thoracoscopy is preferable to thoracotomy for identifying this small group of patients who could potentially benefit from a surgical resection. Thoracoscopy is also useful for staging both lung and esophageal cancer because it may complement cervical mediastinoscopy and allows staging of mediastinal lymphadenopathy.13 Ideally, diagnostic thoracoscopy and surgical resection can be performed sequentially during the same period of general anesthesia.14 Although curative resections can be performed thoracoscopically,15–17 it is unlikely that this technique will replace standard open surgical approaches for lobectomy and pneumonectomy. Chylothorax Thoracoscopy has changed diagnostic and therapeutic approaches to patients with chylothorax. Chylothorax is usually caused by trauma or malignancy (primarily lymphoma). Thoracoscopic exploration may precede or replace an open thoracotomy. If the torn thoracic duct is visualized (having the patient drink heavy cream about 1 h prior to the procedure may facilitate its detection), it can be clipped or ligated endoscopically. Although survival is often limited in case of chylothorax from lymphoma, talc pleurodesis may provide satisfactory resolution of effusions and prevent deterioration of respiratory, nutritional, and immunologic status.18 Lung Parenchymal Disease Thoracoscopic lung biopsy helps establish the diagnosis of diffuse or focal interstitial lung disease and pulmonary infection.19 In addition, it provides tissue for mineralogic studies of the pneumoconioses, and for diagnosis of pulmonary infiltrates or peripheral nodular lesions of unknown etiology. Specimens are usually obtained using an endoscopic stapling device. Strict adherence to the classic principles of carcinologic surgery should prevent parietal and pleural seeding of tumor cells after thoracoscopic removal of lung nodules or masses.20 In many cases, patients can be discharged from the hospital in , 3 days with little morbidity. In one prospective study, morbidity rates were only 1.5, 2.1, and 9.8%, respectively, in the elderly, patients with poor lung function, and patients with depressed performance status.21 Postoperative stay in an ICU is rarely necessary. Thoracoscopy has prompted many practitioners to consider lung biopsy earlier in the management algorithm of patients with parenchymal disease of unclear origin, especially when bronchoscopic lung biopsies have been nondiagnostic.22 It is
noteworthy that the role of thoracoscopic surgery in patients with metastatic pulmonary nodules is unclear.23 Spontaneous and Secondary Pneumothorax Thoracoscopy provides an excellent alternative to repeated chest tube drainage in patients with recurrent or prolonged (usually . 5 days) pneumothorax.24 Thoracoscopy allows definitive treatment or inspection prior to performance of a lateral or axillary thoracotomy.25 Thoracoscopic findings in patients with spontaneous pneumothorax include normal appearance, pleural adhesions, small blebs (, 2 cm) on the visceral pleural surface, and large bullae (. 2 cm). Lesions can be removed using electrocautery, argon plasma coagulation, or stapled lung resection, with results that are similar to those obtained after open thoracotomy (although the resultant pleurodesis may be somewhat less effective: recurrence rates are reportedly 5 to 10% vs only 1 to 3% after open thoracotomy).26 Talc insufflation for pleurodesis may also be effective.27 Although most operators perform these procedures using general anesthesia, thoracoscopic wedge resection of blebs and bulla using local anesthesia has been reported.28 Mediastinal Tumors A thoracoscopic approach has been advocated for patients with posterior and middle mediastinal tumors. Access can be difficult, however, and it may be necessary to convert to open thoracotomy in . 10% of instances.29 Postoperative hospitalization is often less than after thoracotomy, but conversion should not be delayed if there is bleeding, the lesion cannot be appropriately exposed, or tumors are large. Vasospastic Disease Thoracoscopic sympathectomies are performed using either electrocautery, dissection, or excision in patients with Raynaud’s syndrome, causalgia, or essential hyperhydrosis.30 Exposure is usually through the anterior chest wall, and procedures can be performed bilaterally at a single setting.31 Empyema During the exudative and organizing phase of empyema, thoracoscopic visualization allows debridement of fibrinous adhesions and evacuation of loculated fluid.32 This procedure may shorten the length of hospital stay and avoid thoracotomy.33 The timing of thoracoscopic intervention is critical, however, and should be considered when chest tube drainage is unsatisfactory after 3 to 5 days. In one study, 82% of patients treated thoracoscopically CHEST / 116 / 5 / NOVEMBER, 1999
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(mostly during the fibrinopurulent stage of empyema) were treated effectively by thoracoscopic debridement.34 The precise role for thoracoscopy instead of chest tube drainage, instillation of fibrinolytic agents, rib resection, or thoracotomydecortication is still controversial. Bullectomy and Lung Volume Reduction Surgery Thoracoscopy is an accepted modality for lung volume reduction surgery, with results that appear similar to those obtained after median sternotomy.35 Endoscopic stapling can be performed with or without buttressing staple lines. Results of bilateral procedures appear better than unilateral procedures, and costs are often less than with median sternotomy.36 Although improvements in pulmonary function, exercise performance, and quality of life have been noted,37 FEV1 often deteriorates toward baseline prelung resection values within 2 years. The role of thoracoscopy vs median sternotomy for bilateral lung volume reduction surgery is currently being evaluated in the National Emphysema Treatment Trial. Chest Trauma Thoracoscopy provides an effective and safe modality by which to initially evaluate and often manage stable patients with blunt or penetrating chest trauma.38 Diaphragmatic injury, hemothorax, and lung parenchymal lacerations can be treated, although difficulties associated with active bleeding, suboptimal single-lung ventilation, or intense pleural inflammation should prompt conversion to an open thoracotomy.
lated to anesthesia, respiratory failure, wound infections, and malignant seeding of the chest wall.42 Potential advantages of thoracoscopy over more conventional techniques include certainty of representative tissue for diagnosis, reduced requirements for postoperative analgesia, shorter hospital stays, and a shorter duration of chest tube drainage compared with thoracotomy.43 Thoracoscopists are studying ways to further eliminate the need for prolonged chest tube drainage after biopsy or pleurodesis,44 and to decrease procedure-related costs by employing reusable instruments. Additional studies are necessary to determine ideal settings for thoracoscopic intervention and to evaluate current perceptions regarding thoracoscopic practice. A recent survey of thoracic surgeons, for example, showed that most thought video-assisted thoracic surgery was an acceptable approach for the diagnosis of indeterminate pulmonary nodules, anterior and posterior mediastinal masses, clotted hemothorax, early empyema, and secondary pneumothorax, and for limited lung cancer treatment.45 Conclusion
Thoracoscopy can be used for ligation of a patent ductus arteriosus,39 as well as to harvest internal thoracic artery in patients undergoing coronary bypass grafting.40 A significant reduction in postoperative pain has been described, attributed to the absence of rigorous chest retractions. It is likely that many other applications for thoracoscopy-assisted cardiovascular surgery will emerge.
Emerging technologies and an increased awareness of what can and cannot be done has prompted health-care providers to venture ever more aggressively into realms in which, previously, only open surgical procedures could be performed. Whether these procedures should be done instead of or in addition to conventional open procedures is being addressed by many investigators. In addition, thoracoscopy allows chest physicians to glance readily into the pleural space, enhancing their understanding of anatomic relationships and pleuropulmonary physiology. Now we must develop ideal venues for physician training and education,46 further improve safety profiles of technically challenging procedures, and effectively disseminate medical digital photography and videography on a global scale. The inclusion of thoracoscopy in this special section of CHEST is an important step in this direction.
Limitations and Future Directions
References
The thoracoscopic approach to a variety of diagnostic and therapeutic problems has few limitations other than a need to demonstrate safety and cost effectiveness compared with more conventional approaches. Procedure-related mortality is rare (0.24%, which is comparable to that of bronchoscopic biopsy) in experienced hands.41 Potential adverse events include bleeding, persistent pneumothorax, intercostal nerve and vessel injury, cardiac disturbances, complications re-
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5 Wilsher ML, Veale AG. Medical thoracoscopy in the diagnosis of unexplained pleural effusion. Respirology 1998; 3:77– 80 6 de Groot M, Walther G. Thoracoscopy in undiagnosed pleural effusions. S Afr Med J 1998; 88:706 –711 7 Renshaw AA, Dean BR, Antman KH, et al. The role of cytologic evaluation of pleural fluid in the diagnosis of malignant mesothelioma. Chest 1997; 111:106 –109 8 Cantao A, Guijarro R, Arnau A, et al. Videothoracoscopy in the diagnosis and treatment of malignant pleural mesothelioma with associated pleural effusions. Thorac Cardiovasc Surg 1997; 45:16 –19 9 Boutin C, Rey F, Viallat JR. Prevention of malignant seeding after invasive diagnostic procedures in patients with pleural mesothelioma: a randomized trial of local radiotherapy. Chest 1995; 108:754 –758 10 Danby CA, Adebonojo SA, Moritz DM. Video-assisted talc pleurodesis for malignant pleural effusions utilizing local anesthesia and IV sedation. Chest 1998; 113:739 –742 11 Colt HG. Thoracoscopic management of malignant pleural effusions. Clin Chest Med 1995; 16:505–518 12 Harvey JC, Erdman CB, Beattie EJ. Early experience with videothoracoscopic hydrodissection pleurectomy in the treatment of malignant pleural effusion. J Surg Oncol 1995; 59:243–245 13 Krasna MJ. Role of thoracoscopic lymph node staging for lung and esophageal cancer. Oncology 1996; 10:793– 802 14 Landreneau RJ, Mack MJ, Dowling RD, et al. The role of thoracoscopy in lung cancer management. Chest 1998; 113(1 Suppl):6S–12S 15 Kawahara K, Iwasaki A, Shiraishi T, et al. Video-assisted thoracoscopic lobectomy for treating lung cancer. Surg Laparosc Endosc 1997; 7:219 –222 16 Lewis RJ, Caccavale RJ, Sisler GE, et al. One hundred videoassisted thoracic surgical simultaneously stapled lobectomies without rib spreading. Ann Thorac Surg 1997; 63:1415–1421 17 Tschernko EM, Hofer S, Bieglmayer C, et al. Early postoperative stress: video-assisted wedge resection/lobectomy vs conventional axillary thoracotomy. Chest 1996; 109:1636 –1642 18 Mares DC, Mathur PN. Medical thoracoscopic talc pleurodesis for chylothorax due to lymphoma: a case series. Chest 1998; 114:731–735 19 Krasna MJ, White CS, Aisner SC, et al. The role of thoracoscopy in the diagnosis of interstitial lung disease. Ann Thorac Surg 1995; 59:348 –351 20 Collard JM, Reymond MA. Video-assisted thoracic surgery (VATS) for cancer: risk of parietal seeding and of early local recurrence. Int Surg 1996; 81:343–346 21 DeCamp MM Jr, Jaklitsch MT, Mentzer SJ, et al. The safety and versatility of video-thoracoscopy: a prospective analysis of 895 consecutive cases. J Am Coll Surg 1995; 181:113–120 22 Ravini M, Ferraro G, Barbieri B, et al. Changing strategies of lung biopsies in diffuse lung diseases: the impact of videoassisted thoracoscopy. Eur Respir J 1998; 11:99 –103 23 Dowling RD, Landreneau RJ, Miller DL. Video-assisted thoracoscopic surgery for resection of lung metastases. Chest 1998; 113(1 Suppl):2S–5S 24 Janssen JP, Schramel FM, Sutedja TG, et al. Videothoracoscopic appearance of first and recurrent pneumothorax. Chest 1995; 108:330 –334 25 Frank MW, Backer CL, Mavroudis C, et al. Axillary thoracoscopy. Ann Thorac Surg 1998; 66:590 –591 26 Andraes B, Lujaan J, Robles R, et al. Treatment of primary and secondary spontaneous pneumothorax using videothoracoscopy. Surg Laparosc Endosc 1998; 8:108 –112
27 Delaunois L, el Khawand C. Medical thoracoscopy in the management of pneumothorax. Monaldi Arch Chest Dis 1998; 53:148 –150 28 Nezu K, Kushibe K, Tojo T, et al. Thoracoscopic wedge resection of blebs under local anesthesia with sedation for treatment of a spontaneous pneumothorax. Chest 1997; 111: 230 –235 29 Demmy TL, Krasna MJ, Detterbeck FC, et al. Multicenter VATS experience with mediastinal tumors. Ann Thorac Surg 1998; 66:187–192 30 Di Lorenzo N, Sica GS, Sileri P, et al. Thoracoscopic sympathectomy for vasospastic diseases. J Soc Laparoendosc Surg 1998; 2:249 –253 31 Noppen M, Vincken W. Thoracoscopic sympathicolysis for essential hyperhidrosis: effects on pulmonary function. Eur Respir J 1996; 9:1660 –1664 32 Karmy-Jones R, Sorenson V, Horst HM, et al. Rigid thorascopic debridement and continuous pleural irrigation in the management of empyema. Chest 1997; 111:272–274 33 Silen ML, Naunheim KS. Thoracoscopic approach to the management of empyema thoracis: indications and results. Chest Surg Clin N Am 1996; 6:491– 499 34 Cassina PC, Hauser M, Hillejan L, et al. Video-assisted thoracoscopy in the treatment of pleural empyema: stagebased management and outcome. J Thorac Cardiovasc Surg 1999; 117:234 –238 35 Kotloff RM, Tino G, Bavaria JE, et al. Bilateral lung volume reduction surgery for advanced emphysema: a comparison of median sternotomy and thoracoscopic approaches. Chest 1996; 110:1399 –1406 36 Ko CY, Waters PF. Lung volume reduction surgery: a cost and outcomes comparison of sternotomy versus thoracoscopy. Am Surg 1998; 64:1010 –1013 37 Keenan RJ, Landreneau RJ, Sciurba FC, et al. Unilateral thoracoscopic surgical approach for diffuse emphysema. J Thorac Cardiovasc Surg 1996; 111:308 –315 38 Abolhoda A, Livingston DH, Donahoo JS, et al. Diagnostic and therapeutic video assisted thoracic surgery (VATS) following chest trauma. Eur J Cardiothorac Surg 1997; 12:356–360 39 Oto O, Hazan E, Aecikel U, et al. Ligation of patent ductus arteriosus by the method of video-assisted thoracoscopic surgery and our other VATS experiences. J Cardiovasc Surg 1998; 39:379 –381 40 Duhaylongsod FG, Mayfield WR, Wolf RK. Thoracoscopic harvest of the internal thoracic artery: a multicenter experience in 218 cases. Ann Thorac Surg 1998; 66:1012–1017 41 Inderbitzi RG, Grillet MP. Risk and hazards of videothoracoscopic surgery: a collective review. Eur J Cardiothorac Surg 1996; 10:483– 489 42 Jancovici R, Lang-Lazdunski L, Pons F, et al. Complications of video-assisted thoracic surgery: a five-year experience. Ann Thorac Surg 1996; 61:533–537 43 Schramel FM, Sutedja TG, Braber JC, et al. Cost-effectiveness of video-assisted thoracoscopic surgery versus conservative treatment for first time or recurrent spontaneous pneumothorax. Eur Respir J 1996; 9:1821–1825 44 Russo L, Wiechmann RJ, Magovern JA, et al. Early chest tube removal after video-assisted thoracoscopic wedge resection of the lung. Ann Thorac Surg 1998; 66:1751–1754 45 Mack MJ, Scruggs GR, Kelly KM, et al. Video-assisted thoracic surgery: has technology found its place? Ann Thorac Surg 1997; 64:211–215 46 Yim AP. Training in thoracoscopy in the Asia-Pacific. Int Surg 1997; 82:22–23
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Thoracoscopy has provided chest physicians and surgeons with an opportunity to rethink their approach to patients with pleural and pulmonary disease. In this brief review, several methods pertaining to videothoracoscopic procedures are described, followed by a summary of the major indications for this procedure. The question of whether a thoracoscopic approach to diagnosis or treatment could replace more conventional approaches is addressed for several disease processes. Finally, a few thoughts about future directions of this emerging technology are shared. (CHEST 1999; 116:1409 –1415) Key words: pleural disease; technology; thoracoscopy; video-assisted thoracic surgery Abbreviation: SVHS 5 Super VHS
endoscopic surgical techniques, regardE volving less of whether skin incisions are required, continue to revolutionize patient care. Possibly the day will emerge when a group of endoscopic surgical specialists is capable of performing a variety of procedures crossing over several organ systems. After all, some might say a scope is always a scope. It is not surprising that our sense of social responsibilities as well as medical curiosity incite us to seek new and potentially less invasive ways of performing diagnostic and therapeutic chest procedures. The endoscopic surgery revolution is a direct result of such innovations. For readers wondering how these emerging technologies and novel procedures will safely find their way into mainstream medical and surgical practice, rest assured: procedural expertise will be rapidly acquired once we introduce new core curriculums: I predict, for example, that training capabilities will soon be enhanced by the incorporation of virtual reality simulators. The purpose of this supplement, however, is not to focus only on the future, but to summarize the present role of emerging technologies in pulmonary practice. In this regard, the inclusion of thoracoscopy in such a supplement is indeed welcome. Although endoscopic visualization of the contents of the pleural space has been performed in Europe since Jacobaeus, the procedure was seldom performed in the United States. For reasons that are still unclear, *From the Division of Pulmonary and Critical Care Medicine, University of California, San Diego, CA. Correspondence to: Henri G. Colt, MD, FCCP, Associate Professor of Medicine, Chief, Interventional Pulmonology, UCSD Medical Center, La Jolla, CA 92037; e-mail: [email protected]
thoracoscopy had fallen into near total oblivion in this country during the last 50 years. During this decade, however, thoracoscopy found its way back into mainstream chest medicine and surgery. This is due, in part, to the impact of laparoscopic surgery on general surgical practice, prompting many thoracic surgeons to modify proven open surgical techniques so that therapeutic procedures could be performed through smaller incisions using specially designed instruments and videotechnology.1 To their credit, thoracic surgical societies have done a remarkable job of describing thoracoscopic surgical techniques, publishing prospective and retrospective reports, introducing training guidelines, and evaluating novel surgical techniques so that video-assisted thoracic surgery could find a proper place among surgical management strategies. The thoracoscopic window to the pleura was also opened by a handful of pulmonologists who pushed the envelope, so to speak, in their efforts to efficiently and effectively diagnose patients with pleural disorders or manage patients with incurable malignant pleural disease. Techniques of thoracoscopic pleural biopsy, fluid drainage, and pleurodesis are now recognized components of the interventional pulmonologist’s practice. Sessions about thoracoscopy and its role in the management of patients with simple and complex pleural diseases are included in today’s postgraduate courses and pulmonary society meetings. Undeniably, the bridges being built between pioneers in “interventional pulmonology” and their thoracic surgery colleagues will result in greater collaborative efforts among present and future generations of health-care providers. CHEST / 116 / 5 / NOVEMBER, 1999
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In the following paragraphs, the technology and methods pertaining to videothoracoscopic procedures are reviewed. A brief description of the major indications for these procedures follows, accompanied by comments on whether a thoracoscopic approach to diagnosis or treatment could replace more conventional approaches. Finally, the closing paragraphs are devoted to a discussion of the potential limitations of thoracoscopy and thoughts about future directions. It goes without saying that I beg the reader’s indulgence for not providing herein an inclusive review of current knowledge and practice of thoracoscopic procedures: a simple MEDLINE search (English language, years from 1990 to 1998) using only thoracoscopy as a key word yielded 1,035 citations. Because of space limitations, I have intentionally limited references to a few selected review articles and original research published in various international journals, representing a broad scope of thoracoscopic practice in both the chest physician’s and chest surgeon’s literature, and for the most part, published since 1995. To the many colleagues and fellow investigators who have published articles in these areas, but whose names I have not cited, your forgiveness is appreciated.
Technology and Instrumentation For many years, visualization of a closed space such as the pleural cavity was possible through a rigid Hopkins lens telescope attached to a cold light source. Only the operator was able to visualize the contents of the pleural space, although occasionally, a single assistant could watch through a “teaching head” attached to the eyepiece of the telescope. Teaching heads reduced the amount of light transmitted through the telescope, and were also extremely expensive, costing several thousand dollars. In addition, the operator could use only one hand to manipulate instruments because the other hand held the telescope. The same was true for the assistant who held the teaching head. Thoracoscopic instruments were designed to facilitate operative procedures. Forceps, graspers, lung manipulators, cautery and cutting devices, suction/ irrigation instruments, and a variety of disposable and reusable pleural trocars and cannulas are currently available. Many of the same instruments used in open thoracic surgery can be used in thoracoscopic surgery; it is really the development of the endoscopic stapling device that expanded the scope of thoracoscopic practice. Of course, the introduction of videotechnology into medical practice also changed our acceptance of 1410
thoracoscopic procedures. Not only have optics considerably improved—telescopes used today have greater depth of field, magnification, and arc of vision— but now multiple assistants and observers can watch an entire procedure. Visualization of the contents of the pleural cavity is facilitated by a videocamera that is attached to the eyepiece of the rigid telescope. The size and quality of these cameras has considerably improved in recent years, and the addition of video makes viewing, documentation, and assisting during procedures far easier than in the days of direct visualization. Newer telescopes magnify the subject being visualized (usually about 43 for a 7-mm rigid telescope), and the increased availability of couplers of varying sizes allow greater depth of field and increased field of vision without distortion to enhance visibility. Image size on the video monitor is affected by the aperture of the telescope, coupler size, and camera sensor size. The larger the coupler, the greater the magnification of the image. Unfortunately, this also decreases the amount of light being transmitted into the already large and relatively dark pleural cavity. Light sources today, however, are able to autoregulate the amount of light being transmitted through fiberoptic light cables, although many operators prefer to manually adjust these light controls. Images are usually recorded using a VHS or Super VHS (SVHS) video recorder/player. It is fascinating that most procedure suites and operating rooms today are stocked with expensive carts and highgrade equipment that is rarely, if ever, used to its full capacity. In fact, for routine patient care purposes, a single-chip videocamera, a basic single standard medical-grade monitor or other video display, and simple VHS videorecorder amply suffice. With a single-chip camera, a segmented multicolor filter is often placed over a single sensor. Although detail is reduced, most physicians are unable to tell the difference compared with a far more expensive three-chip camera. For thoracoscopists who require quality images for preparation of educational materials such as CDROMs, however, higher-grade equipment is often desirable. Not surprisingly, the costs associated with the acquisition of high-grade equipment can be excessive. A three-chip camera, for example, may cost as much as $12,000. In addition, these cameras are bulkier, heavier, and less comfortable to handle. A three-chip camera splits light into the three separate colors (red, green, and blue, or RGB). The video signals are then distributed as separate red, green, and blue signals with separate synchronizing pulses, as a combined composite video signal, or as two separate signals (known as luminance and chrominance, or Y/C). Global Theme Issue: Emerging Technology in Clinical Medicine
The image is recorded onto a typical VHS recorder (with a line resolution of only 250 lines), or an SVHS video recorder (with a line resolution of . 400 lines). It is noteworthy that the conventional television screen has a line resolution of only 320 vertical lines, although more advanced video displays have a resolution of about 560 lines. By recording master images on SVHS rather than VHS, dubs (copies) will be of greater quality. The costs of a good SVHS deck is approximately $1,200 (about $2,500 for a medicalgrade deck), compared with less than $400 for a VHS deck; the SVHS videotapes used daily are also more costly than VHS tapes. SVHS tapes cannot be viewed on VHS decks (which are the decks most people have at home next to their television sets), so subsequent editing and dubbing onto VHS is mandatory. Of course, with higher-quality television sets and the advent of the digital versatile disc, or DVD, SVHS inputs may soon become commonplace for in-home use. Thoracoscopic exploration, however, is unlikely to undergo a radical change in the immediate future. Certain advances are necessary to improve documentation sources and to keep up with changes occurring in the world of communication, such as transmission over the World Wide Web. Eventually, images will be captured and recorded digitally before being transferred to CD-ROM for editing and storage. These changes will not be required, however, for the majority of thoracoscopists using videotechnology for simple observation and documentation. Eventually, smaller telescopes with excellent illumination and visualization capabilities may be used for microthoracoscopy; a thoracoscope with distal charge-coupled device will be developed2; and an enhanced flexible fiberoptic videothoracoscope may find its way into the same day procedure suite a` la flexible fiberoptic bronchoscopy.
Clinical Applications Thoracoscopy is usually performed through one or several small, , 2-cm skin incisions made along the intercostal spaces. Patients are placed in the lateral decubitus position, involved side up, although some procedures, such as a thoracic sympathectomy, are performed with patients in the supine position. Pleural trocars can also be safely placed in the axilla, so that axillary thoracoscopy can potentially precede an axillary thoracotomy. IV sedation and local anesthesia are administered using techniques similar to those employed when making a chest tube insertion incision. Many operators prefer general anesthesia with single- or double-lumen endotracheal intubation performed in an operating suite. Certainly, the
operating room is the accepted procedural area for diagnostic and therapeutic procedures such as lung biopsies, decortication, or cardiovascular interventions. Many procedures limited to removal of pleural fluid, visualization, and biopsy of parietal pleura can be performed through a single skin incision made in approximately the fifth to seventh intercostal space along the lateral chest wall of the involved hemithorax. When a 5- to 10-mm pleural trocar and cannula are inserted through the incision, the parietal pleura, diaphragm, and lung are well visualized. Pleural fluid is evacuated and parietal pleural biopsy specimens are obtained from both normal- and abnormalappearing areas. A chest tube is placed through the incision site and connected to a suction device, and the lung is gently reexpanded. Because the duration of chest tube drainage can be only a few hours, many patients are discharged the same day. In years past, this type of procedure was commonly referred to as pleuroscopy. Today, because of the very minimally invasive nature of the procedure, it has become known as “medical thoracoscopy.”3 Complications such as bleeding (from parietal pleural biopsy), lung perforation (during trocar insertion), or infection (from inadvertently using nonsterile techniques) are extremely rare.4 Advanced diagnostic and therapeutic procedures are usually performed in an operating suite. Multiple incisions allow the introduction of biopsy forceps, endoscopic scissors, electrocautery, suction-irrigation instruments, and grasping forceps to allow greater mobilization of the lung, removal of fibrin deposits or blood clots, and sectioning of adhesions that prevent complete inspection of the pleural space and mediastinum. Sometimes these adhesions also inhibit complete lung expansion; they may also maintain patency of visceral pleural tears in patients with spontaneous or secondary pneumothorax. In patients with complex pleural effusions, suspected underlying trapped lung requiring an attempt at reexpansion using positive pressure ventilation, empyema, and multiloculated pleural effusions from infection or malignancy, the pleural space and mediastinum can be safely explored using general anesthesia and multiple access sites. Although comparative studies have not been performed, it is possible that complication rates may be increased in this setting because of the increased morbidity of patients undergoing these procedures, the use of general anesthesia, and the invasive scope of procedures being performed. Pleural Effusion of Unknown Etiology Algorithms for investigating pleural effusion of unknown etiology typically begin with thoracentesis. CHEST / 116 / 5 / NOVEMBER, 1999
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Because cytologic examination is diagnostic in only 60 to 80% of patients with metastatic pleural involvement and in , 20% of patients with mesotheliomas, however, thoracoscopic parietal pleural examination and biopsy present an exciting opportunity to achieve earlier diagnosis.5 Most experts agree that when the initial evaluation of a pleural effusion is nondiagnostic, especially when neoplastic disease is suspected, thoracoscopic exploration and parietal pleural biopsy should be considered.6 The diagnostic accuracy of thoracoscopy is between 90 and 100%, compared with an approximate sensitivity of 44% for closed needle pleural biopsy and 62% for fluid cytology; false negatives occur most frequently in cases of early malignant mesothelioma. If the patient has a malignancy and negative cytology on thoracentesis, thoracoscopy is preferred over closed needle pleural biopsy because it will establish the diagnosis in . 90% of cases. Tuberculous Pleurisy The greater debate is whether thoracoscopy is warranted if tuberculosis is high on the list of differential diagnoses. In exudative pleural effusions due to tuberculosis, the diagnostic yield of a closed needle biopsy is 70 to 90%. Thoracoscopy is usually unnecessary, therefore, to establish the diagnosis of a tuberculous effusion. A combined yield of only 6% for thoracoscopy preceded by negative thoracentesis and closed needle pleural biopsy has been reported. Thoracoscopy may be beneficial in difficult diagnostic situations, however, when lysis of adhesions is necessary, or when larger amounts of tissue are warranted to assure diagnosis when drug resistance is suspected. Malignant Mesothelioma Although malignant mesothelioma may be suspected based on a history of asbestos exposure, symptoms, radiographic findings of pleural fluid, thickening, absence of contralateral shift of the mediastinum, and clinical course, diagnostic confirmation is often difficult. Pleural fluid cytology ranges from 4 to 77%, and representative specimens from closed needle biopsy are rarely of sufficient size and number to allow the full battery of immunohistochemical stains and electron microscopic examination for definitive diagnosis.7 Even with thoracoscopy, the accuracy of diagnosing mesothelioma may suffer because of inadequate visualization due to extensive adhesions and the inherent difficulties in pathologic identification of this tumor.8 Thoracoscopy allows removal of large, full-thickness specimens from several involved areas, making it potentially preferable to open pleural biopsy by minitho1412
racotomy, and most certainly preferable to lateral thoracotomy. Symphysis between visceral and parietal pleural surfaces and the absence of pleural fluid can make these procedures technically challenging. For patients not considering intrapleural chemotherapy or surgical resection, pleurodesis can be performed at the time of diagnostic thoracoscopy in order to prevent fluid reaccumulation and to delay the onset of lifethreatening dyspnea. Although tumor growth through thoracoscopic incision sites has been described,9 it is probably less frequent than reported. Prevention is possible by treating the area surrounding the incision sites with radiation. Patients should be warned that such prophylactic radiation could potentially make them ineligible for some clinical trials. Malignant Pleural Effusions In addition to diagnosis, an important indication for thoracoscopy in patients with malignant pleural effusions is pleurodesis.10 Complete evacuation of pleural fluid, maximization of lung expandability by removing adhesions, and pleurodesis by talc insufflation (also known as talc poudrage) results in shortand long-term success rates of . 90%.11 Distribution of sterile, asbestos-free, US Pharmacopeia–approved talc powder on all pleural surfaces is confirmed by thoracoscopic visualization. Following pleurodesis, low-grade fevers should be expected in up to 30% of patients, and hospitalization duration averages 4.8 days. Pleurodesis can also be achieved by pleurectomy using standard dissection techniques or hydrodissection.12 Because survival of patients with advanced pleural carcinomatosis is often short, the risks and benefits of thoracoscopic pleurodesis must be carefully weighed against those of repeat thoracentesis, tube thoracostomy, or bedside pleurodesis through an indwelling chest tube. Recurrent Pleural Effusions of Benign Etiology Recurrent pleural effusions of benign etiology are frequently caused by heart failure, cardiac surgery, nephrotic syndrome, connective tissue diseases, and other inflammatory disorders. Thoracoscopy may be warranted when recurrent effusions cause symptoms and are not controlled by repeated large-volume thoracentesis. Usually, pleural biopsy specimens are obtained to exclude infectious or neoplastic etiologies, and pleurodesis is performed. Results are usually excellent when talc is used, with success rates varying from to 65 to . 90%. Lung Cancer Most pleural effusions associated with lung cancer result from direct carcinomatous involvement of the Global Theme Issue: Emerging Technology in Clinical Medicine
pleura. Even patients in whom cytologic examination of pleural fluid is negative are often found on thoracotomy to have unresectable lesions. Thoracoscopy is preferable to thoracotomy for identifying this small group of patients who could potentially benefit from a surgical resection. Thoracoscopy is also useful for staging both lung and esophageal cancer because it may complement cervical mediastinoscopy and allows staging of mediastinal lymphadenopathy.13 Ideally, diagnostic thoracoscopy and surgical resection can be performed sequentially during the same period of general anesthesia.14 Although curative resections can be performed thoracoscopically,15–17 it is unlikely that this technique will replace standard open surgical approaches for lobectomy and pneumonectomy. Chylothorax Thoracoscopy has changed diagnostic and therapeutic approaches to patients with chylothorax. Chylothorax is usually caused by trauma or malignancy (primarily lymphoma). Thoracoscopic exploration may precede or replace an open thoracotomy. If the torn thoracic duct is visualized (having the patient drink heavy cream about 1 h prior to the procedure may facilitate its detection), it can be clipped or ligated endoscopically. Although survival is often limited in case of chylothorax from lymphoma, talc pleurodesis may provide satisfactory resolution of effusions and prevent deterioration of respiratory, nutritional, and immunologic status.18 Lung Parenchymal Disease Thoracoscopic lung biopsy helps establish the diagnosis of diffuse or focal interstitial lung disease and pulmonary infection.19 In addition, it provides tissue for mineralogic studies of the pneumoconioses, and for diagnosis of pulmonary infiltrates or peripheral nodular lesions of unknown etiology. Specimens are usually obtained using an endoscopic stapling device. Strict adherence to the classic principles of carcinologic surgery should prevent parietal and pleural seeding of tumor cells after thoracoscopic removal of lung nodules or masses.20 In many cases, patients can be discharged from the hospital in , 3 days with little morbidity. In one prospective study, morbidity rates were only 1.5, 2.1, and 9.8%, respectively, in the elderly, patients with poor lung function, and patients with depressed performance status.21 Postoperative stay in an ICU is rarely necessary. Thoracoscopy has prompted many practitioners to consider lung biopsy earlier in the management algorithm of patients with parenchymal disease of unclear origin, especially when bronchoscopic lung biopsies have been nondiagnostic.22 It is
noteworthy that the role of thoracoscopic surgery in patients with metastatic pulmonary nodules is unclear.23 Spontaneous and Secondary Pneumothorax Thoracoscopy provides an excellent alternative to repeated chest tube drainage in patients with recurrent or prolonged (usually . 5 days) pneumothorax.24 Thoracoscopy allows definitive treatment or inspection prior to performance of a lateral or axillary thoracotomy.25 Thoracoscopic findings in patients with spontaneous pneumothorax include normal appearance, pleural adhesions, small blebs (, 2 cm) on the visceral pleural surface, and large bullae (. 2 cm). Lesions can be removed using electrocautery, argon plasma coagulation, or stapled lung resection, with results that are similar to those obtained after open thoracotomy (although the resultant pleurodesis may be somewhat less effective: recurrence rates are reportedly 5 to 10% vs only 1 to 3% after open thoracotomy).26 Talc insufflation for pleurodesis may also be effective.27 Although most operators perform these procedures using general anesthesia, thoracoscopic wedge resection of blebs and bulla using local anesthesia has been reported.28 Mediastinal Tumors A thoracoscopic approach has been advocated for patients with posterior and middle mediastinal tumors. Access can be difficult, however, and it may be necessary to convert to open thoracotomy in . 10% of instances.29 Postoperative hospitalization is often less than after thoracotomy, but conversion should not be delayed if there is bleeding, the lesion cannot be appropriately exposed, or tumors are large. Vasospastic Disease Thoracoscopic sympathectomies are performed using either electrocautery, dissection, or excision in patients with Raynaud’s syndrome, causalgia, or essential hyperhydrosis.30 Exposure is usually through the anterior chest wall, and procedures can be performed bilaterally at a single setting.31 Empyema During the exudative and organizing phase of empyema, thoracoscopic visualization allows debridement of fibrinous adhesions and evacuation of loculated fluid.32 This procedure may shorten the length of hospital stay and avoid thoracotomy.33 The timing of thoracoscopic intervention is critical, however, and should be considered when chest tube drainage is unsatisfactory after 3 to 5 days. In one study, 82% of patients treated thoracoscopically CHEST / 116 / 5 / NOVEMBER, 1999
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(mostly during the fibrinopurulent stage of empyema) were treated effectively by thoracoscopic debridement.34 The precise role for thoracoscopy instead of chest tube drainage, instillation of fibrinolytic agents, rib resection, or thoracotomydecortication is still controversial. Bullectomy and Lung Volume Reduction Surgery Thoracoscopy is an accepted modality for lung volume reduction surgery, with results that appear similar to those obtained after median sternotomy.35 Endoscopic stapling can be performed with or without buttressing staple lines. Results of bilateral procedures appear better than unilateral procedures, and costs are often less than with median sternotomy.36 Although improvements in pulmonary function, exercise performance, and quality of life have been noted,37 FEV1 often deteriorates toward baseline prelung resection values within 2 years. The role of thoracoscopy vs median sternotomy for bilateral lung volume reduction surgery is currently being evaluated in the National Emphysema Treatment Trial. Chest Trauma Thoracoscopy provides an effective and safe modality by which to initially evaluate and often manage stable patients with blunt or penetrating chest trauma.38 Diaphragmatic injury, hemothorax, and lung parenchymal lacerations can be treated, although difficulties associated with active bleeding, suboptimal single-lung ventilation, or intense pleural inflammation should prompt conversion to an open thoracotomy.
lated to anesthesia, respiratory failure, wound infections, and malignant seeding of the chest wall.42 Potential advantages of thoracoscopy over more conventional techniques include certainty of representative tissue for diagnosis, reduced requirements for postoperative analgesia, shorter hospital stays, and a shorter duration of chest tube drainage compared with thoracotomy.43 Thoracoscopists are studying ways to further eliminate the need for prolonged chest tube drainage after biopsy or pleurodesis,44 and to decrease procedure-related costs by employing reusable instruments. Additional studies are necessary to determine ideal settings for thoracoscopic intervention and to evaluate current perceptions regarding thoracoscopic practice. A recent survey of thoracic surgeons, for example, showed that most thought video-assisted thoracic surgery was an acceptable approach for the diagnosis of indeterminate pulmonary nodules, anterior and posterior mediastinal masses, clotted hemothorax, early empyema, and secondary pneumothorax, and for limited lung cancer treatment.45 Conclusion
Thoracoscopy can be used for ligation of a patent ductus arteriosus,39 as well as to harvest internal thoracic artery in patients undergoing coronary bypass grafting.40 A significant reduction in postoperative pain has been described, attributed to the absence of rigorous chest retractions. It is likely that many other applications for thoracoscopy-assisted cardiovascular surgery will emerge.
Emerging technologies and an increased awareness of what can and cannot be done has prompted health-care providers to venture ever more aggressively into realms in which, previously, only open surgical procedures could be performed. Whether these procedures should be done instead of or in addition to conventional open procedures is being addressed by many investigators. In addition, thoracoscopy allows chest physicians to glance readily into the pleural space, enhancing their understanding of anatomic relationships and pleuropulmonary physiology. Now we must develop ideal venues for physician training and education,46 further improve safety profiles of technically challenging procedures, and effectively disseminate medical digital photography and videography on a global scale. The inclusion of thoracoscopy in this special section of CHEST is an important step in this direction.
Limitations and Future Directions
References
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