Undiagnosed pleural effusion is an increasingly common clinical problem and represents significant burden of disease both to patients and healthcare resources. With the increase in annual incidence of both primary and secondary pleural malignancies, better diagnostics and treatment options are very much needed. Medical thoracoscopy, also known as local anaesthetic thoracoscopy [2], is a procedure where a rigid or semi-rigid scope is inserted into the pleural cavity via a port for direct visualisation of the pleura and biopsy of abnormal areas, besides completion of talc poudrage, where appropriate. It is usually performed under conscious sedation and local anaesthesia. This procedure avoids risks of general anaesthesia and single lung ventilation, required for video-assisted thoracoscopic surgery (VATS) and therefore can be performed in patients who are unfit for anaesthesia/surgery. The procedure of thoracoscopy is performed in a controlled environment such as in an operating theatre setting, endoscopy suite or treatment room with adequate staffing. Diagnostic advantage A significant number of cases of pleural effusion are undiagnosed after a single diagnostic pleural aspiration and the diagnostic yield of pleural fluid cytology is only approximately 60% [3]. A second aspiration only modestly increases diagnostic yield by 15% and a third sample is non-contributory [3]. A blind pleural biopsy (also known as closed pleural biopsy) increases the diagnostic yield above pleural fluid cytology by only 7-27% [3]. In mesothelioma however, the diagnostic yield of pleural fluid cytology is even lower, at around 32% [4]. A blind pleural biopsy only increases sensitivity to around 50% [5]. Medical thoracoscopy is substantially superior in diagnostic power compared to pleural fluid cytology and blind pleural biopsy. As it allows direct visual assessment of the pleura and subsequent biopsy of the abnormal areas, it maximises diagnostic yield to >90% in malignant pleural diseases [5,6]. Rigid thoracoscopy generates similar diagnostic yield compared to semirigid thoracoscopy in exudative pleural effusions but larger biopsy samples can be obtained during rigid thoracoscopy [5,6]. The sensitivity of medical thoracoscopy in malignant mesothelioma appears to be equally good and the efficacy of rigid medical thoracoscopy in regards to diagnosis in pleural malignancy is as high as VATS [2]. With the increasing need to secure an accurate diagnosis and plan optimal treatment in possible pleural malignancy, medical thoracoscopy offers a high diagnostic yield earlier in the patient journey. Therefore, this is the preferred procedure where the option exists and helps to reduce the need for repeated diagnostic procedures and reduces the time taken to establish diagnosis and commence appropriate treatment. Medical thoracoscopy as a therapeutic procedure Another advantage of medical thoracoscopy is that it is a diagnostic and therapeutic procedure in the same setting. Complete drainage of pleural fluid can be achieved during the procedure and talc poudrage can also be performed during medical thoracoscopy. It is a highly effective method of pleurodesis with an efficacy of 84% at 1 month, which is at least equivalent to talc slurry via a seldinger chest drain, with possibly increased efficacy in the subgroup of patients who have breast or lung carcinoma and without trapped lung [2]. Medical thoracoscopy is also effective in the management of TB pleurisy and empyema. Septations and adhesions in complex infected effusions can be divided during thoracoscopy which can facilitate accurate chest tube placement and drainage. Advanced Thoracoscopy Techniques Narrow Band Imaging- using Semirigid Thoracoscope Autofluorescence Rigid Thoracoscopy Biopsy- with Insulated Tip Diathermy Knife Cryobiopsy- using Semirigid Thoracoscope Rigid Thoracoscope Semi-rigid Thoracoscope Diacon AH, Van de Wal BW, Wyser C, et al. Diagnostic tools in tuberculous pleurisy: a direct comparative study. Eur Respir J 2003;22:589e91. Rahman NM, Ali NJ, Brown G, Chapman SJ, O’Davies RJ, Downer NJ, Gleeson FV, Howes TQ, Treasure T, SinghS and Phillips GD Local anaesthetics thoracoscopy: British Thoracic Society pleural disease guideline 2010. Thorax 2010;65(Suppl 2):ii54-ii60 Mohan A, Chandra S, Agarwal D, Naik S and Munavvar M. Utility of semirigid thoracoscopy in the diagnosis of pleural effusions: a systematic review. Journal of Bronchology and Interventional Pulmonology 17 (3), 195-201 Munavvar M, Khan MAI, Edwards J, Waqaruddin Z and Mills J. The autoclavable semirigid thoracoscope: the way forward in pleural disease? Eur Respir J 2007; 29: 571-574 Dhooria S, Singh N, Agarwal AN, Gupta D and Agarwal R. A randomized trial comparing the diagnostic yield of rigid and semirigid thoracoscopy in undiagnosed pleural effusion. Respir Care 2014:59 (5), 756-764 Rozman A, Camlek L, Marc-Malovrh M, Triller N, Kern I. Rigid versus semi-rigid thoracoscopy for diagnosis of pleural disease: a randomized pilot study. Respirology, 2013 May;18(4):704-10. Loddenkemper R, Lee P, Noppen M, Mathur PN. Medical thoracoscopy/pleuroscopy: step by step. Breathe. 2011;8(2):156-67. Rigid Thoracoscopy, Semi-rigid Thoracoscopy, Advanced Techniques