BackgroundThe optimal placement of a chest drain after video-assisted minimally invasive lobectomy should facilitate the aspiration of air and drainage of fluid. Typically, a conventional 24Ch polyvinyl chloride chest drain is used for this purpose. However, there is currently no scientific literature available on the impact of drain diameter on postoperative outcomes following anatomical lung resection. MethodsThis is a prospective, randomized, phase-1 trial that will include 40 patients, which will be randomly assigned into two groups. Group 1 will receive a 24 French chest drain according to current standards, while group 2 will receive a 14 French drain. Primary endpoint of the trial is the incidence of postoperative drainage-related complications, such as obstruction, dislocation, pleural effusion, and reintervention. Secondary endpoints are postoperative pain, chest drainage duration, incidence of complications, and hospital length of stay. The study aims to determine the number of subjects needed to achieve a sufficient test power of 0.8 for a non-inferiority study. DiscussionThoracic surgery is becoming more and more minimally invasive. One of the remaining unresolved problems is postoperative pain, with the intercostal drain being one of the main contributing factors. Previous data from other studies suggest that the use of small-bore drains can reduce pain and speed up recovery without an increase in drain-related complications. However, no studies have been conducted on patients undergoing anatomic lung resections to date. The initial step in transitioning from larger to smaller drains is to establish the safety of this approach, which is the primary objective of this trial.Trial registration: The study has been registered in the German Clinical Trials Register.Registration number: DRKS00029982.URL: https://drks.de/search/de/trial/DRKS00029982.