Thoracoscopy is an old technique invented in 1910 at the same time as laparoscopy by a Swedish physician named Jacobeus. For a long time thoracoscopy was performed to achieve pneumonolysis in patients with tuberculosis. More recently many physicians in Europe have documented the usefulness of thoracoscopy for pneumonological indications other than tuberculosis. In recent years, following the first endoscopic appendicectomy1, many surgeons have become interested in minimally invasive surgery and video-assisted thoracic surgery. Some have been very active in developing the method but numerous trained chest physicians continue to perform thoracoscopy2-4. In fact, a distinction must be made between medical thoracoscopy which may be video-assisted and surgical thoracoscopy or V.A.T.S. (video-assisted thoracoscopic surgery). In this report we describe techniques widely used by physicians in Europe, the United States5-7 or Canada8. In 1980, we organized the First International Symposium on thoracoscopy in Marseilles9. In 1987 Loddenkemper organized a second Symposium in Berlin10.
Diagnostic or therapeutic exploration of the pleural cavity is performed using one or several points of entry. In addition to visual inspection of the thoracic cavity, a number of procedures can be performed. Biopsies can be collected from the pleura and, more rarely, the lung. Adhesions preventing exploration can be cut. Coagulation can be performed to stop bleeding or remove small blebs or superficial bullae in patients with spontaneous pneumothorax. A pleural drain is placed at the end of the examination to ensure prompt expansion of the lung against the chest wall. If lung biopsy or pleurodesis is performed, the mean duration of drainage is 3-4 days. In simple cases involving pleurisy, the examination can be performed as an ambulatory procedure.
To practice thoracoscopy, a chest physician needs specific training to learn thoracic anatomy, use of instrumentation (biopsy forceps, coagulation systems, video-endoscopic equipment), and surveillance of drainage during the recovery period. To stay in practice pulmonologist should perform at least 20-25 thoracoscopies a year. Interventional chest physicians are often also interested in rigid bronchoscopy stents and laser endoscopy as well as in brachytherapy and cryotherapy in some cases.
HOW TO PRACTICE THORACOSCOPY
Equipment requirements include trocars, telescopes, biopsy forceps, coagulation forceps, light sources, video camera, aspiration system, and surgical instrumentation such as scissors, snares, abraders, staplers, clip insectors, etc. The usual diameter of the telescope is 7 mm but surgeons often prefer larger ports (10 mm).
The procedure room can be an operating room or a sterile endoscopy suite equipped with a procedure table, anesthesia equipment, Mayo stands, a roller tray for instruments, diathermo-coagulation and patient monitoring devices.
The anesthesia technique varies. Local anesthesia can be performed after premedication and sedation. Neuroleptanalgesia with an association of benzodiazepam, droperidol and alfentanyl can be used. General anesthesia can be done using propofol or another suitable product. Medical thoracoscopy does nor normally require tracheal intubation but surgeons practice selective intubation with a double lumen tube.
The examination is performed with the patient lying on the healthy side. The entry site is generally made on the axilla midline in the 3rd to 7th intercostal spaces. A procedure includes the following phases:
• careful aspiration of secretions;
• inspection using a lateral viewing or a direct viewing telescope;
• insufflation of air into the cavity if necessary;
• section of adhesions preventing inspection;
• collection of multiple biopsy samples (wall, diaphragm, lung) for light microscopy, electronic microscopy, hormone receptor assay, mineral detection, bacteriology, tumor culture;
• aspiration for fluid cytology;
• talc pleurodesis if necessary;
• systematic suction drainage;
• control x-ray;
• surveillance during recovery.
Thoracoscopy is one of the safest pneumonological examinations. In a review of 8000 cases, Viskum and Enk noted only one death. In his review Viskum found that there was no mention of wound infection in any study, that empyema occurred in only 12 of 652 cases in 3 studies, and that hemorrhage occurred in 6 of 356 cases described in 3 other studies. O2 desaturation during thoracoscopy under local anesthesia is reportedly less than 2%.
Complications can best be prevented by observing the following rules:
1. Postpone thoracoscopy for several days if the patient is coughing;
2. Measure blood gases, monitor cardiac signs by simultaneous ECG;
3. Oxygenate the patient during thoracoscopy;
4. Avoid taking biopsy samples from the internal parts of the fissures or from the mediastinum;
5. Coagulate and ensure hemostasis if hemorrhage exceeds 20 ml.
6. Insert a chest tube (at least until the lung expands) to prevent subcutaneous emphysema;
7. Start physiotherapy on the day of thoracoscopy to exercise the diaphragm and avoid accumulation of secretions and obstruction;
8. To prevent invasion in cases of mesothelioma, administer radiation therapy of 7 grays/day for 3 days to the scar area on postoperative day 10.
WHEN TO PRACTICE THORACOSCOPY
Basic indications for medical thoracoscopy
Diagnosis of pleurisy
Whether it is recent or chronic, pleurisy poses a difficult diagnostic problem. In 20% of cases repeated fluid cytology studies and Abrams, Cope or Boutin needle biopsies fail to achieve diagnosis. In patients with tuberculosis or cancer, the sensitivity of these two examinations never exceeds 60-70%. In contrast thoracoscopy with biopsy of the parietal, diaphragmatic and visceral pleura allows diagnosis in 95-98%. Based on these findings, it seems ill-advised to wait for pleurisy to progress. In patients with no diagnosis at the end of 8-15 days, thoracoscopy should be carried out.
In most cases of pneumothorax the lung appears endoscopically normal or presents small blebs or bullae no larger than 1 to 2 cm in diameter. In such cases coagulation of the offending leak and talc pleurodesis can be easily performed and achieves lasting results in about 95% of cases (Viskum).
Talc pleurodesis for chronic and recurrent pleurisy
Talc pleurodesis for chronic and recurrent pleurisy, particularly malignant pleurisy (metastatic cancer or mesothelioma) achieves lasting results in 90% of cases. Talc must be asbestos-free and sterilized in an autoclave prior to use. For pneumothorax, 2 to 4 ml of talc depending on the size of the lung should be used to avoid complications as well as immediate or late sequelae. For chronic pleurisy, 6 to 8 ml of talc are needed, as a large part is rapidly lost through the suction drain.
Talc pleurodesis for chylothorax
Talcage can also be indicated for chylothorax as well as in some cardiac diseases and cirrhoses involving effusion.
Some indications are classified in a grey zone between medical and surgical thoracoscopy. They can be performed depending on the training and competence of the operator and on patient recruitment. To perform these procedures doctors or surgeons must have special skills to guarantee patient safety. The procedure should be performed in a very well experienced endoscopic center.
Lung biopsy using coagulation forceps or an endostapler can be performed for diffuse interstitial lesions, pulmonary fibrosis, and, in some cases, pneumoconiasis, granulomatosis, sarcoidosis, histiocytosis, etc. or accessible peripheral lung lesions.
Section of adhesions and debridment
Purulent pleurisy and early empyema can be treated by section of adhesions and debridment before placement of a drain in a multiloculated cavity. Drainage under visual control achieves excellent results within days.
Other procedures that can be performed by a skilled operator include sympatholysis (Wittmoser), pericardial window, placement of injections ports for intrapleural treatment, etc.