Thoracoscopy
Although thoracoscopy has been a part of thoracic surgical practice for many years, the advent of video-assisted techniques has greatly expanded the indications and the uses of this procedure. In the past, thoracoscopy was performed mainly for diagnostic purposes. Presently, video-assisted thoracic surgery (VATS) has assumed a major role in the therapy of chest pathology. Indeed, in some institutions it is now the most commonly used operative approach in the general thoracic surgical practices (1). The primary advantage of VATS is that it produces less morbidity and mortality, and shorter duration of hospitalization than does thoracotomy. Presently, VATS is used for many surgical procedures in the chest other than those related to pleural disease including pulmonary nodule removal, lobectomy, lung biopsy, exploration of the mediastinum, myotomy for achalasia, sympathectomy, esophagectomy, and pericardial window creation. In this chapter, we discuss only those procedures that deal with pleural disease.
It is important to understand that there are two different techniques for thoracoscopy—VATS and medical thoracoscopy. VATS is performed in an operating room under general anesthesia with the patient selectively intubated to allow for single lung ventilation. Multiple puncture sites are made in the chest wall through which the thoracoscope and surgical instruments are introduced. Medical thoracoscopy differs from VATS in that the patient is usually not intubated and breathes spontaneously (2). The procedure is usually performed with conscious sedation and local anesthesia. Medical thoracoscopy primarily serves as a diagnostic tool rather than for intervention. It is usually performed by pulmonologists, whereas VATS is performed by thoracic surgeons (2). The primary advantages of medical thoracoscopy are that it can be performed in an endoscopy suite, it does not involve general anesthesia, and is less expensive than VATS (2). For diagnostic purposes, either VATS or medical thoracoscopy is appropriate and the choice of procedure depends primarily on its availability at one’s institution. The number of centers performing medical thoracoscopy in the United States and the United Kingdom is gradually increasing. For example, between 1999 and 2004 the number of centers in the United Kingdom where medical thoracoscopy was performed increased from 11 to 17 (3).
HISTORY
Thoracoscopy was developed by Jacobaeus in the early 1900s because a method was needed to break down adhesions in patients with pulmonary tuberculosis so that an artificial pneumothorax could be produced (4). Thoracoscopy was used extensively for this purpose until 1945, at which time streptomycin was introduced for the treatment of tuberculosis (5). In one report, the results in 1,000 patients in whom thoracoscopy was used to break down adhesions were detailed (6). Jacobaeus also published an early report on the use of thoracoscopy to localize and diagnose benign and malignant lesions of the pleura and pulmonary parenchyma (7).
After 1950, thoracoscopy was rarely performed in the United States, although some physicians in Europe continued to perform the procedure (8). During this period, thoracoscopy was used primarily to assist in diagnosing pleural effusions, although pleurodesis was sometimes attempted with talc (9,10) or silver nitrate (11,12). A number of instruments were employed including rigid bronchoscopes, mediastinoscopes, flexible bronchoscopes, and specialized rigid fiber-optic
thoracoscopes (13). Two older books (14,15) provide state-of-the-art discussions on thoracoscopy before the advent of VATS, which has become available mainly since 1990.
thoracoscopes (13). Two older books (14,15) provide state-of-the-art discussions on thoracoscopy before the advent of VATS, which has become available mainly since 1990.
The recent revival of thoracoscopy was made possible by the tremendous advances in endoscopic technology (16). The development of the charged coupling device and a silicon chip that is light sensitive led to the sufficient miniaturization of a video camera. When attached to a fiber-optic telescope, the video camera produces a well-defined, magnified image on a video monitor that allows the operating surgeon to work with an assistant. Previously, the surgeon had to hold the thoracoscope, and only he could look into it while working, which did not allow for the aid of an assistant and, therefore, limited the complexity of the procedures undertaken (13).
PROCEDURE
Medical Thoracoscopy
Training Requirements for Medical Thoracoscopy
The guidelines from the American College of Chest Physicians (ACCP) recommend that trainees should perform at least 20 procedures in a supervised setting to establish basic competency. Then to maintain competency, dedicated operators should perform at least 10 procedures per year (17).
There are two fundamental techniques by which medical thoracoscopy is performed, namely, single puncture and double puncture (18). Both techniques require a xenon light source, which satisfies the requirements for high-quality visual exploration and video documentation. For the single-puncture technique, a rigid thoracoscope with a 9-mm working channel is used. With the single-puncture technique, various instruments such as the biopsy forceps, needle biopsy, and suction catheter are used through the working channel, which also accommodates electrocautery. For the double-puncture technique, a smaller 7-mm rigid thoracoscope is used along with a second smaller 5-mm trocar that accommodates biopsy forceps, brushes, needles, and laser fibers. The single-puncture technique is the easiest method to learn and is commonly used by the chest physician (18).
Medical thoracoscopy can be done either under direct visual control through the endoscopic optic or indirectly by video transmission that allows a magnified view and demonstration to assistants and others, as well as appropriate documentation (18). For cauterization of adhesions and blebs, or in case of bleeding after biopsy, electrocoagulation or laser coagulation should be available.
Medical thoracoscopy is usually performed under local anesthesia, but some premedication (e.g., midazolam) should be routinely administered. Thoracoscopy is usually performed with the patient in the lateral decubitus position with the hemithorax to be studied facing upward.
The site for the introduction of the thoracoscope depends upon the location of radiographically detected abnormalities, while avoiding potentially hazardous areas such as that of the internal mammary artery, the axillary region with the lateral thoracic artery, and the infraclavicular region with the subclavian artery. It is important not to insert the thoracoscope too low because the diaphragm or spleen may be accidentally injured (18). The usual site for insertion of the thoracoscope is in the sixth or seventh intercostal space between the mid- and anterior-axillary lines.
Before the thoracoscope is introduced, a pneumothorax of several hundred cubic centimeters of air is usually induced (18). Thoracic ultrasound prior to thoracoscopy improves pleural access and predicts fibrous septation (19). Examination of the pleural space is only possible if the space between the lung and chest wall is sufficiently large to move the instruments around easily and to visualize all important areas of the thoracic cavity (15). After the trocar is introduced, the pleural fluid should be removed as completely as possible. Then the entire pleural cavity is inspected. Biopsies are obtained from suspicious areas. Biopsies from the visceral pleural are usually obtained only when the parietal pleura appears normal but the lung surface shows abnormal lesions. Following thoracoscopy, a chest tube should be introduced and connected to suction.
In the last few years, new instrumentation has been developed which may facilitate medical thoracoscopy. Tassi and Marchetti (20) reported their experience with a technique called minithoracoscopy in which two 3.8-mm trocars, one with a 3.3-mm telescope and the other with a 3.0-mm biopsy forceps were used for undiagnosed pleural effusion. They reported that the diagnostic yield with this procedure was 90% and concluded that it is most useful for assessment of small effusions not accessible to conventional medical thoracoscopy (20) and for patients with narrow intercostal spaces (21).
Ernst et al. (22) described their experience with a newly developed semirigid pleuroscope in the evaluation of the pleural space. This pleuroscope was
developed so that it interfaces with existing processors and light sources that are routinely employed for flexible bronchoscopy and are available in most endoscopy units. An additional benefit is that this pleuroscope operates much like a bronchoscope, and therefore it should be easier to use by the pulmonologist who is not trained in the use of rigid instruments (22,23).
developed so that it interfaces with existing processors and light sources that are routinely employed for flexible bronchoscopy and are available in most endoscopy units. An additional benefit is that this pleuroscope operates much like a bronchoscope, and therefore it should be easier to use by the pulmonologist who is not trained in the use of rigid instruments (22,23).
Video-Assisted Thoracic Surgery
Most VATS procedures are performed under general anesthesia because with general anesthesia, endoscopic surgical manipulation can be accomplished safely and expeditiously (1). It is imperative that the anesthesia personnel be experienced in open thoracic procedures. In addition, they must be well versed with the principles of selective one-lung ventilation. Although most surgeons perform VATS with a double-lumen endotracheal tube, it can be performed with a single-lumen endotracheal tube if only a pleural effusion is to be drained and a biopsy obtained of the parietal pleura (24). Ventilation for the patient is provided through the contralateral lung. It is most convenient to work with two video monitors, one on each side, so that both the operator and the assistant may have an unobstructed view. VATS has also been performed with local anesthesia and sedation (25).
The patient is placed on the operating table, and the chest is prepared and draped as for a thoracotomy. After general anesthesia is induced, the thoracoscope is inserted and the ipsilateral lung is collapsed for unimpaired visibility of the intrathoracic structures. At this time, the thoracic cavity is systematically examined. After the initial thoracoscopic exploration of the pleural cavity is concluded, further intercostal access for VATS instrumentation is achieved under direct thoracoscopic vision. Usually, three incisions are made to create a triangular configuration, an arrangement that facilitates instrument placement and allows one to work in coordination with an assistant. The incisions are placed along a line appropriate for a thoracotomy incision so that if a subsequent thoracotomy is required, the incisions are simply joined. At the completion of the VATS procedure, a single chest tube is placed in the pleural space.
Instrumentation for VATS is slowly improving. Initially, instruments designed for laparoscopy were used but were less than ideal, particularly for grasping lung parenchyma, which has a tendency to tear. The most significant advance in instrumentation was the development of an endoscopic linear stapler, which simultaneously cuts while laying down parallel rows of staples that are both hemostatic and aerostatic (Endo-GIA, U.S. Surgical Corp., Norwalk, CT, USA).
The operative time for a patient with an undiagnosed pleural effusion is short. Cerfolio et al. (24) reported that when a single-lumen tube was used for undiagnosed pleural effusion, the mean operative time for pleural evaluation and pleural biopsy in a series of more than 200 patients was only 17 minutes.
Previous thoracoscopy has been considered a relative contraindication to a second thoracoscopy. However, Breen et al. (26) reported that they performed redo thoracoscopies in 29 patients and were able to induce a pneumothorax and complete the procedure in all patients although pleural adhesions were more common with the redo procedures. Most of their patients had malignant pleural effusions.
CONTRAINDICATIONS TO THORACOSCOPY
The two primary contraindications to thoracoscopy are the inability to tolerate one-lung ventilation and pleural adhesions of sufficient density to preclude entry into the chest (13,18). Of course, the patient must be able to tolerate general anesthesia and must not have bleeding abnormalities that would preclude other surgical procedures.
INDICATIONS AND RESULTS
Undiagnosed Pleural Effusion
On occasion, the etiology of a pleural effusion remains uncertain after the initial diagnostic workup, which includes a diagnostic thoracentesis with pleural fluid cytology, a pleural fluid marker for tuberculosis, and an evaluation for pulmonary embolus. Such patients are possible candidates for thoracoscopy to establish the etiology of the pleural effusion. It should be noted, however, that the only two diagnoses that are usually established with thoracoscopy are malignancy and tuberculosis. If the patient has a pleural effusion due to a different etiology, the diagnosis in all probability will not be established at thoracoscopy.
Thoracoscopy is an efficient way to establish the diagnosis of malignancy. In the early 1990s, two separate studies, each with 102 patients, were published that reported diagnostic yields of 93% (27) and 80% (28). However, when these two studies are examined in detail, one finds that the only diagnosis that was definitely established is malignancy. When the two studies mentioned in the preceding text are combined,
the diagnosis of malignancy was established in 99 of the 117 patients (85%) with malignancy, including 51 of 56 (91%) with mesothelioma. In a more recent study from Denmark, medical thoracoscopy established the diagnosis in 89 of 101 patients (88%) with malignancy (29). Preliminary results in one study suggest that the use of autofluorescence videothoracoscopy may help identify areas of the pleura with malignant involvement (30). Thoracoscopy can also establish the diagnosis of tuberculosis (31,32,33). In one study from South Africa, the diagnosis of tuberculosis was established with thoracoscopy in all 42 patients with tuberculous pleuritis (33).
the diagnosis of malignancy was established in 99 of the 117 patients (85%) with malignancy, including 51 of 56 (91%) with mesothelioma. In a more recent study from Denmark, medical thoracoscopy established the diagnosis in 89 of 101 patients (88%) with malignancy (29). Preliminary results in one study suggest that the use of autofluorescence videothoracoscopy may help identify areas of the pleura with malignant involvement (30). Thoracoscopy can also establish the diagnosis of tuberculosis (31,32,33). In one study from South Africa, the diagnosis of tuberculosis was established with thoracoscopy in all 42 patients with tuberculous pleuritis (33).
Where is the rightful place of thoracoscopy in the management of the patient with an undiagnosed pleural effusion? Thoracoscopic procedures should be used only when the less invasive methods of diagnosis such as pleural aspiration for cytologic, bacteriologic, and chemical examinations have not yielded a diagnosis. In one series of 620 patients with pleural effusions, only 48 (8%) remained without a diagnosis and were subjected to thoracoscopy (34). In these 48 patients, a diagnosis of malignancy was established in 24 (50%), and in an additional 16 patients, the diagnosis of benign disease was established when the thoracoscopic and clinical findings were considered jointly. In the remaining eight patients (16%), no diagnosis was established at thoracoscopy, but six of them were subsequently diagnosed as having malignancy (34). Thoracoscopy is recommended for the patient with an undiagnosed pleural effusion in whom the diagnosis of malignancy or tuberculosis is suspected, and in whom at least one pleural fluid cytology and one pleural fluid marker for tuberculosis (adenosine deaminase or interferon) have been negative.
There are clinical findings that make it more likely that malignancy will be diagnosed at the time of thoracoscopy. Ferrer et al. (35) prospectively studied 93 patients referred for thoracoscopy at a tertiary hospital. They found that the following four variables were associated with pleural malignancy in a multivariate model: (a) a symptomatic period of more than 1 month, (b) absence of fever, (c) blood-tinged pleural fluid, and (d) chest computed tomography (CT) findings suggestive of malignancy (pulmonary or pleural masses, pulmonary atelectasis, or lymphadenopathy) (35). Twenty-eight patients had all four criteria and all had malignancy. Twenty-one patients had at most one criterion and none had malignancy.
When one performs thoracoscopy for diagnostic purposes, it is important to be prepared to perform a procedure to create a pleurodesis during surgery. Our preferred method is pleural abrasion with an alternative being the instillation of 100 mL of 2% iodopovidone (36). The efficacy of mechanical abrasion was documented in one study in which 87 patients with malignant effusions secondary to breast carcinoma were randomized to receive pleurodesis by mechanical abrasion in conjunction with thoracoscopy or by talc slurry (37). Pleurodesis with mechanical abrasion had a higher success rate (89%) than pleurodesis with talc slurry (74%) (37). Although talc insufflation was recommended in the earlier editions of this book, concerns about respiratory failure occurring after talc administration (see Chapter 10) have led to this different recommendation. If talc is used in this situation, only graded (large particle size) talc should be used. It should also be noted that the performance of thoracoscopy without any attempt to create a pleurodesis will result in a pleurodesis in more than 50% of patients with malignant pleural effusions (38,39).
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