Uniportal video-assisted thoracic surgery: a call for better evidence, not just more evidence.

The advent of uniportal video-assisted thoracic surgery (uniportal VATS) has energized the worldwide thoracic surgery community in recent years. This approach promises the least access trauma of any minimally invasive thoracic surgical technique thus far, but it has also opened a deep rift among surgeons [1, 2]. Proponents point to the potential for reduced morbidity and faster recovery offered by uniportal VATS. Opponents suggest that the reduced access to the chest may compromise safety and therapeutic efficacy of the surgery. The arguments on both sides are strongly voiced and hold merit. Perhaps, the only point on which both sides agree is that more clinical evidence is needed to settle this debate—the outcome of which holds considerable importance for patients. In this light, the paper authored by Perna et al. [3] in this issue should be warmly welcomed by thoracic surgeons. It is a prospective randomized study comparing uniportal VATS with other styles of VATS. It employs a sound process of randomization, a comprehensive selection of outcome measures and a thorough analysis of the collected data. From this, they have reached a conclusion that uniportal VATS offers no measurable benefits compared with other VATS approaches when performing lung lobectomy. We applaud the authors for endeavouring to produce the clinical data that the thoracic surgery community badly needs on uniportal VATS. Certainly, more studies from more centres must be performed to define the optimal strategies for lobectomy in future. However, closer scrutiny reveals that this paper—like virtually any clinical research paper—has its limitations and flaws. For example, this study had only non-significant results. The conclusion of ‘non-superiority’ of uniportal VATS is reliable only if the sample size estimation was done meticulously. Yet, the authors based their sample size estimation on finding a difference of ‘at least 2 points’ on the 10-point visual analogue scale (VAS)— which is perhaps unrealistic. Many papers comparing pain after various approaches for thoracic surgery have found differences between study arms of much less than 2 points on a 10-point scale [4]. It has further been found in human clinical studies that the minimum clinically significant difference in VAS for pain is less than 2 points [5]. If the sample size estimation had been conducted to find a more common difference of less than 2 points, then this study would have been underpowered and the failure to find a difference between the study arms may be seen to be a type 2 statistical error. Another important point of note was that the authors grouped the Duke technique with the Copenhagen technique in Group B. But by definition, these are two very different approaches, and the Duke technique is actually closer to uniportal surgery than to the Copenhagen approach. Thomas d’Amico himself points out that his technique is essentially a variant of the uniportal technique in that only a single intercostal access is used, albeit with an additional small skin incision [6]. By arbitrarily putting the Duke technique together with the Copenhagen technique for analysis, the authors are potentially putting uniportal-like results together with the three-portal arm, and possibly skewing results in favour of three-portal. Readers should, therefore, take caution when considering the conclusions suggested. Given the potential—but also potentially fundamental—weaknesses of the study, one should not automatically read it as a proof of uniportal VATS not delivering on its promises of better patient outcomes. Rather, it may be more a case of study methodology failing to convincingly deliver the unequivocal evidence surgeons are looking for. The above limitations are pointed out not to disparage the authors in any way. On the contrary, their efforts in conducting and publishing a study to explore the possible benefits of the uniportal approach are much appreciated. The above observations are instead made to highlight the need for not only a greater quantity of clinical evidence in the uniportal debate but also a greater quality of evidence. Looking back at the history of multiportal VATS since the 1990s, it can be seen in hindsight that the establishment of this minimally invasive approach was considerably hampered by a rush to publish in the early years [7]. Among the