A randomized trial comparing the diagnostic yield of rigid and semirigid thoracoscopy in undiagnosed pleural effusions.
BACKGROUND
Thoracoscopic pleural biopsy increases the diagnostic yield of pleural effusions undiagnosed after thoracentesis and is superior to closed pleural biopsy. Medical thoracoscopy can be performed using the rigid thoracoscope or the semirigid thoracoscope (pleuroscope). In this randomized trial, we compare the efficacy and safety of the 2 thoracoscopes.


METHODS
Subjects with undiagnosed exudative pleural effusions were randomly assigned to undergo pleural biopsy with either the rigid or the semirigid thoracoscope. The primary outcome was the diagnostic yield of the procedure, while the secondary outcomes were requirement of sedative/analgesic agents, scar size, biopsy sample size, and the operator's view of the procedure.


RESULTS
Of the 145 screened subjects with exudative pleural effusions, 90 were randomized to undergo thoracoscopy with the 2 thoracoscopes (n = 45 each). The diagnostic yield of rigid thoracoscopy was superior to semirigid thoracoscopy (97.8% vs 73.3%, P = .002) on an intention-to-treat analysis but was similar (100% vs 94.3%, P = .18) in those with successful biopsy. The requirement of sedative/analgesic agents was higher in the rigid thoracoscopy arm. The scar size was slightly larger (mean ± SD, 23.1 ± 4 vs 18.7 ± 3.2 mm, P = .0001), whereas the biopsy sample size was distinctly larger in the rigid arm (mean ± SD, 13.9 ± 4.4 vs 4.4 ± 1.4 mm, P = .001). The operator-rated visual analog scale score for the ease of taking a biopsy sample was significantly higher with the rigid instrument (mean ± SD, visual analog scale 86 ± 12 vs 79 ± 12 mm, P = .01), while the quality of image was superior in the semirigid arm (mean ± SD, visual analog scale 88 ± 7 vs 92 ± 5 mm, P = .002). The number of complications were similar in the 2 groups.


CONCLUSIONS
Rigid thoracoscopy was found to be superior to semirigid thoracoscopy overall, but the diagnostic yield was similar if pleural biopsy could be successfully performed. Due to the small sample size, a larger study is required to define the usefulness and choice between the 2 procedures. (ClinicalTrials.gov registration NCT01726556).