An overview of medical thoracoscopy

INTRODUCTION

Pleural effusion, pneumothorax, and pleural thickening are frequently encountered in pulmonary practice. Although the radiographic detection of pleural abnormalities may be obvious, determination of a specific diagnosis can present a challenge. Computed axial tomographic (CT) scans of the thorax and bronchoscopy with transbronchial biopsies may be helpful in selected circumstances, but the diagnostic yield for pleural disease is disappointingly low [1,2].  Percutaneous access to the pleural space is diagnostically useful and relatively simple; however, approximately 25 percent of pleural abnormalities remain undiagnosed after thoracentesis and/or closed pleural biopsies [3-6]. CT-guided Abrams needle biopsy is a reasonable initial diagnostic procedure if pleural thickening is the main abnormality [7].

Thoracoscopy (or pleuroscopy) involves passage of an endoscope through the chest wall and offers the clinician a "window" for direct visualization and collection of samples from the pleura. It is a valuable diagnostic procedure and, in some cases, can also provide an opportunity for treatment [8]. The technique and instruments used for thoracoscopy are reviewed here. The diagnostic indications for "medical thoracoscopy," as performed by a pulmonologist, and its use as a therapeutic modality are discussed separately. (See "Indications for diagnostic thoracoscopy" and "Therapeutic uses of medical thoracoscopy".)

HISTORICAL BACKGROUND

The initial effort to view the pleural space using endoscopic techniques (a modified cystoscope) was reported in 1910 [9]. Pleural adhesions were lysed in 40 patients, and diagnostic evaluation of pleural-based tumors was reported in another 120. Subsequently, thoracoscopy was widely used to lyse pleural adhesions or to induce an artificial pneumothorax, a mainstay of therapy for pulmonary tuberculosis in the early 20th century.

The number of thoracoscopies declined after the introduction of effective antituberculous drugs. In addition, the Abrams and Cope biopsy needles proved reasonably efficacious for the diagnosis of malignant and tuberculous pleural effusions, precluding a major role for diagnostic thoracoscopy [10,11]. The current wave of interest in thoracoscopy, both inside and outside the operating room [5,6,12-22], has occurred because of:

• Improvements in endoscopic video systems
• Availability of local anesthetics, sedatives, and narcotics that preclude the need for general anesthesia and ventilatory support in selected cases