Semirigid versus Single-port Rigid Thoracoscopy in the Evaluation of Undiagnosed Exudative Pleural Effusion: A Quasi-experimental Comparative Study

BACKGROUND: Medical thoracoscopy is a key diagnostic tool for undiagnosed exudative pleural effusion. Rigid and semirigid thoracoscopes differ in design, potentially influencing procedural pain, sedative requirements, and diagnostic yield. This study compared rigid versus semirigid thoracoscopy in terms of efficacy, safety, and patient tolerance. METHODS: In this quasi-experimental study, 172 patients underwent rigid thoracoscopy (Group A) and 164 underwent semirigid thoracoscopy (Group B). Baseline demographics, clinical features, and pleural fluid characteristics were comparable. Procedural parameters, complications, pleural morphology, and histopathological and mycobacteriological findings were recorded. Diagnostic yield, analgesic/sedative use, and procedural pain were analyzed. RESULTS: The mean age was 62.1 years in Group A and 59.1 years in Group B. Pain during trocar insertion (77.3% vs. 19.5%), thoracoscope maneuvering (64% vs. 7.3%), and pleural biopsy (83.1% vs. 37%) was significantly higher in the rigid group ( P < 0.001). Accordingly, midazolam and fentanyl requirements were greater in rigid thoracoscopy. Pleural adhesions were present in 22.1% (rigid) and 25% (semirigid), occasionally complicating scope insertion. Pleural morphology was comparable, with thickening, nodules, and masses most common. Overall diagnostic yield was 97.1% for rigid and 93.9% for semirigid thoracoscopy ( P > 0.05). Both modalities demonstrated comparable diagnostic performance and overall safety despite differences in procedural discomfort. Minor complications occurred in 19% and 10.3%, and major complications in 7% and 4.9% of rigid and semirigid groups, respectively ( P > 0.05). No procedure-related mortality was observed. CONCLUSION: Both rigid and semirigid thoracoscopy provide high diagnostic accuracy and a favorable safety profile. Semirigid thoracoscopy offers significantly less procedural pain and lower sedative/analgesic requirements, enhancing patient comfort without compromising diagnostic yield. These findings highlight semirigid thoracoscopy as a patient-friendly and clinically effective diagnostic option for exudative pleural effusion without compromising diagnostic yield.