AbstractOBJECTIVESInherent technical aspects of pulmonary lobectomy by video-assisted thoracoscopic surgery (VATS) may limit surgeons’ ability to deal with factors predisposing to complications. We analysed complication rates after VATS lobectomy in a prospectively maintained nationwide registry.METHODSThe registry was queried for all consecutive VATS lobectomy procedures from 49 Italian Thoracic Units. Baseline condition, tumour features, surgical techniques, devices, postoperative care, complications, conversions and the reasons thereof were detailed. Univariable and multivariable regressions were used to assess factors potentially linked to complications.RESULTSFour thousand one hundred and ninety-one VATS lobectomies in 4156 patients (2480 men, 1676 women) were analysed. The median age-adjusted Charlson index of the patients was 4 (interquartile range 3–6). Grade 1 and 2 and Grade 3–5 complications were observed in 20.1% and in 5.8%, respectively. Ninety-day mortality was 0.55%. The overall conversion rate was 9.2% and significantly higher in low-volume centres (<100 cases, P < 0.001), but there was no significant difference between intermediate- and high-volume centres under this aspect. Low-volume centres were significantly more likely to convert due to issues with difficult local anatomy, but not significantly so for bleeding. Conversion, lower case-volume, comorbidity burden, male gender, adhesions, blood loss, operative time, sealants and epidural analgesia were significantly associated with increased postoperative morbidity.CONCLUSIONSVATS lobectomy is a safe procedure even in medically compromised patients. An improved classification system for conversions is proposed and prevention strategies are suggested to reduce conversion rates and possibly complications in less-experienced centres.