Medical Thoracoscopy

Rigid Thoracoscopy or Flexi-rigid Pleuroscopy?

Kim Hoong Yap; Martin J. Phillips; Y.C. Gary Lee


Curr Opin Pulm Med. 2014;20(4):358-365. 

In This Article

Rigid vs. Flexi-rigid Pleuroscopy: Diagnostic Yield

International guidelines suggest thoracoscopy be considered for the 25% of exudative pleural effusions that remain undiagnosed after thoracentesis and closed pleural biopsy.[13,14] In tuberculous pleuritis, the combined yield of histology and culture for rigid thoracoscopy was nearly 100%.[15,16]

In malignant pleural diseases, rigid thoracoscopy achieved a high diagnostic yield of 95% in one study.[16] However, in three other series of medical thoracoscopy, patients with a thoracoscopic biopsy result of 'nonspecific pleuritis' had a 10–15% chance of having an underlying pleural malignancy, most commonly mesothelioma.[10–12]

Published data on flexi-rigid pleuroscopy remain relatively limited. Most studies were small and did not always contain the necessary variety of pleural malignancies (e.g. mesothelioma) and the range of diagnostic difficulties.

A systematic review by Mohan et al.[17] included five studies (154 patients) on flexi-rigid pleuroscopy in the diagnosis of undiagnosed pleural effusions, and showed a pooled sensitivity of 97%, specificity of 100%, a positive likelihood ratio (PLR) of 5.47 and negative likelihood ratio (NLR) of 0.08. These studies were also reported in a more recent meta-analysis by Agarwal et al.[18] that included 17 studies (755 patients), 9 of which were prospective and only 1 was a randomized trial. Flexi-rigid pleuroscopy showed a good sensitivity (91%) and specificity (100%) in diagnosing exudative pleural effusions. The PLR and NLR were 4.92 and 0.08, respectively.

Although larger specimens are preferred, two randomized trials and one prospective comparative study showed no significant difference in the diagnostic yield between rigid and flexi-rigid pleuroscopy. Khan et al.[19] studied 66 patients [42 with malignancy and two with tuberculosis (TB)] from two centers in a nonrandomized study, and reported similar diagnostic yields between the flexi-rigid and rigid thoracoscopy (92.3 vs. 96.3%).

Rozman et al.[20] published the first randomized study with 84 patients comparing the diagnostic adequacy of biopsy specimens obtained at rigid and flexi-rigid pleuroscopy. They found similar diagnostic accuracy with rigid (100%) and flexi-rigid instruments (97.6%) even though specimens obtained through the rigid forceps were considerably larger (24.7 vs. 11.7 mm2). The negative predictive values for rigid and flexi-rigid biopsies were 100 and 92.3% respectively. In this cohort, 60% of patients had malignant pleural disease, of which two-thirds were mesothelioma.

In another study, Dhooria et al.[9] randomized 90 patients to undergo rigid or flexi-rigid pleuroscopy. The diagnostic yield for rigid thoracoscopy was noted to be superior to flexi-rigid pleuroscopy on an intention-to-treat analysis (97.8 vs. 73.3%) but was similar (100 vs. 94.3%) after excluding patients in whom pleuroscopy was not feasible because of extensive adhesions. One major limitation in this study was patient selection. Seven of the forty-five patients from the flexi-rigid thoracoscopy arm crossed over to the rigid thoracoscopy arm because of the lack of pleural space and only a quarter of the whole cohort had prior computed tomography (CT) of the chest or thoracic ultrasound. Unlike the previous studies, malignancy was the final cause in only a third of the patients, whereas a quarter was because of TB.

These studies have obvious limitations, but nonetheless there has not been clear evidence to suggest that smaller biopsies result in inferior diagnostic accuracy. The size of biopsies from the flexi-rigid scope would be comparable to those from standard bronchoscopes, which is usually adequate for endobronchial tissue sampling.