Thoracoscopy is not a new technique, but recent technological developments have increased its applicability to general thoracic surgery. In 1910, a Swedish physician, Hans Christian Jacobeus performed the first thoracoscopy when he placed a cystoscope in the pleural cavity to diagnose pleuritis. Until recently, thoracoscopy has had limited utility, being used mostly for pneumothorax therapy of tuberculosis or biopsies of pleural disease. The application of miniaturized video technology to thoracoscopy and the development of percutaneous tools and techniques have allowed thoracic surgeons to perform complex procedures using minimally invasive techniques.

Video thoracoscopes exploit a charged coupling device, which is a silicon-based chip sensitive to light. This small integrated circuit functions as a television camera. When coupled with a thoracoscope, it allows inspection of the chest cavity through a small incision. Rigid thoracoscopes provide excellent resolution but, because of the relative inflexibility of the chest wall, they cannot allow visualization of the entire pleural cavity. The flexible thoracoscope with a charged coupling device at its distal end allows acceptable resolution combined with manoeuvrability in the chest cavity. The disadvantages of the flexible thoracoscope are its greater complexity, increased expense, and more frequent mechanical breakdown.

Another piece of equipment that is useful in thoracoscopic surgery is the percutaneous GIA stapler. The device places two triple rows of staples while concomitantly dividing the tissue between the staple lines. It allows the surgeon to perform a wedge excision of the lung thoracoscopically. The stapler is available in a 30 or 60mm length and is disposable. A reusable stapler and a stapler with an articulating head are in the developmental stage.

Since thoracoscopy does not require CO&sub2; insufflation, sealed ports are not necessary, as in laparoscopy. A variety of tools used in standard thoracotomy procedures can therefore be used for thoracoscopy. For example, a pediatric Duval lung clamp serves as a grasper or retractor of the lung. A curved ring forceps can be used to remove specimens from the chest cavity or to decorticate the lung. Specialized disposable graspers, scissors, and retractors are available and useful in special circumstances, but are quite expensive. Although laser beams have been used in thoracoscopy, they permit only a poor pleurodesis, and they cloud the pleural cavity with smoke. The incidence of air leaks after pulmonary resection with laser is increased and raises the cost and complexity of a thoracoscopic procedure. Similarly, the argon beam coagulator has limited utility.

Because video thoracoscopy is still developing, indications and procedures are evolving. Pulmonary wedge excision using thoracoscopic techniques is safe and useful in a variety of situations. The technique is applicable to the management of an indeterminate pulmonary nodule. Thoracoscopic percutaneous wedge excision of a peripheral nodule yields an accurate diagnosis with minimal morbidity. For nodules that are difficult to locate, palpation of the lung through the thoracoscopic incision helps locate the nodule. There is often a subtle pleural reaction that localizes an underlying nodule. Mack has described preoperative wire localization, similar to that used in breast biopsies, to help locate nodules. Finally, Hazelrigg described preoperative injection of methylene blue into the lung near the nodule to help localization at thoracoscopy.

If frozen section of a nodule identifies a bronchogenic carcinoma, thorascopic wedge excision alone is inadequate therapy. Initial data from the Lung Cancer Study Group indicates that local recurrence of bronchogenic carcinoma is three to four times higher following a wedge excision than after a lobectomy. Thus, a pathology report of bronchogenic carcinoma from a frozen section of an indeterminate pulmonary nodule necessitates conversion to an open procedure and performance of a lobectomy and mediastinal node dissection unless the patient's pulmonary function is severely limited (i.e., FEV&sub1; <0.6). When examination of frozen section of an indeterminate nodule seen on computed tomography (CT) reveals metastatic cancer, wedge excision via thoracoscopy is also inadequate therapy. Several studies have demonstrated that CT misses up to 50 per cent of metastatic pulmonary nodules. Thoracoscopic resection alone, which limits careful palpation of the remaining lung, may therefore miss metastases and produce lower cure rates. In patients with diffuse interstitial infiltrates, thoracoscopic wedge biopsy can provide a diagnosis by percutaneous wedge excision. We do not recommend percutaneous wedge biopsy in patients who are ventilated and require high FiO&sub2;, because of the risks of double-lumen intubation in these patients. Lewis described lobectomy of the lung, although an incision long enough to remove the lobe was required. Thoracoscopy has also had limited success for staging bronchogenic carcinoma, specifically in evaluating aortopulmonary window nodules.

Pleural effusions and pleural masses may also be diagnosed and treated via thoracoscopy by pleural biopsy, decortication, and pleurodesis. For malignant pleural effusion, talc pleurodesis is preferred. For benign diseases when pleural symphysis is desired, mechanical abrasion of the parietal pleura is performed. Recurrent spontaneous pneumothorax can be treated by percutaneous excision of the offending bullae and gauze pleurodesis using thoracoscopy. Although mediastinal masses, including neurogenic tumours, thymomas, pericardial cysts, and lymphadenopathy have been treated thoracoscopically, malignant mediastinal masses should not be resected thoracoscopically because of the limited access.

Several surgeons have reported performing thoracoscopic truncal vagotomy and a modified Heller myotomy, using concomitant oesophagoscopy to facilitate exposure. Initial reports of this procedure are encouraging, but it cannot be considered standard treatment. Thoracoscopy has also been used to resect benign oesophageal tumours and to assist in oesophagectomy. No one has yet reported a transthoracic antireflux procedure, but laparoscopy has been used to perform an antireflux wrap. Finally, thoracoscopy has been used for a cervical sympathectomy to treat hyperhidrosis or reflux sympathetic dystrophy.

In the United States, surgeons use double-lumen general anaesthesia, for thoracoscopy, whereas European surgeons use local anaesthesia. The patient is placed in a lateral decubitus position, and the ipsilateral lung is collapsed. A 1.0cm incision in the mid-axillary line over the eighth rib provides access to the pleural space.

Digitally palpate the pleural space to ensure it is not obliterated, then pass the thoracoscope into the chest. Make additional incisions, when necessary, with direct thoracoscopic vision. CO&sub2; insufflation is not necessary and may cause tension pneumothorax or air embolism. At the completion of the procedure, insert a chest tube through one of the incisions and reinflate the lung under direct vision. Close the remaining incisions in layers. The procedure is not painless, and most patients require some form of postoperative analgesia, although considerably less than after a standard thoracotomy. If there is no air leak and minimal drainage from the chest tube, remove the tube the day after surgery and discharge the patient from the hospital.

Complications are infrequent. The most common are pneumothoraces after chest tube removal and prolonged air leaks. Pneumothoraces may result from air entering through the chest tube tract. Closing the initial thoracoscopic tract and inserting the thoracostomy tube through a different tract, but in the same incision, eliminates this problem. Massive haemorrhage is uncommon, since dissection around major vessels can be a problem. At present, there is no satisfactory way to control massive haemorrhage thoracoscopically. Safe dissection of large vessels awaits improved tools and techniques.

Equipment may malfunction. We have had several instances of the stapler jamming on the lung which required a thoracotomy to remove the stapler. This probably occurs when there was too much tissue between the jaws of the stapler.

Other investigators have reported a variety of complications from thoracoscopy including injury to the phrenic, recurrent, or intercostal nerves, wound infection, re-expansion pulmonary oedema, air embolism, and tracheal trauma from the double lumen tube. Poor image quality and fogging of the lens can frustrate the surgeon and lead to inadvertent lung injury.

Video thoracoscopy is a new application of an established technique, the full potential of which is yet to be defined. It is effective only if used selectively and certainly is not a panacea for all the ills of a thoracotomy. The costs of the procedure are not much different when compared with a thoracotomy, because of the added expense of specialized thoracoscopic instruments. However, the advantage is an earlier return to work or normal activities for the patient after a thoracoscopy versus thoracotomy. Surgeons must not be lured into performing an inadequate, minimally invasive procedure for short-term benefits. The proper application of video thoracoscopic surgery still needs resolving. The future should bring answers to these questions, as well as further advances in the technology of thoracoscopy.

Landreneau RJ, et al. Video-assisted thoracic surgery: basic technical concepts and intercostal approach strategies. Ann Thoracic Surg 1992; 54: 800–7.

Mack MJ, et al. Percutaneous localization of pulmonary nodules for thoracoscopic lung resection. Ann Thoracic Surg 1992; 53: 1123–4.

Miller DL, et al. Videothoracoscopic wedge excision of the lung. Ann Thoracic Surg 1992; 54: 410–14.