Robot-assisted and video-assisted thoracoscopic surgery for thymoma: comparison of the perioperative outcomes using inverse probability of treatment weighting method.

Background: Minimally invasive surgery is the standard treatment for early-stage thymoma. We compared the perioperative outcomes between robot-assisted thoracoscopic surgery (RATS) and video-assisted thoracoscopic surgery (VATS) for thymoma. Methods: Between April 2011 and August 2021, patients with thymoma who underwent thymectomy by RATS (n=20) or VATS (n=37) at our hospital were retrospectively reviewed. We evaluated the postoperative quality of life (QOL), surgical outcomes, complications, mortality, and pain grade. Postoperative QOL was assessed according to the time to achieve "B duration" and "CIII duration" based on the Nursing Dependency Score and Nursing Criteria, respectively. Results: After the inverse probability of treatment weighting (IPTW), the B duration and CIII duration were significantly shorter with RATS than with VATS (P<0.001 and P=0.037, respectively). These superior results of RATS group compared to those of the VATS group were confirmed with logistic regression analysis (OR 0.25, 95% CI: 0.10-0.63, P=0.003; and OR 0.31, 95% CI: 0.12-0.76, P=0.011, respectively). After the IPTW, the VATS group had significantly fewer patients with epidural analgesia than the RATS group (P=0.018). In contrast, additional regular analgesics (including those for wound pain and neuralgia) were prescribed significantly more often during postoperative hospitalization in the VATS group (P=0.033). Patients in both groups had no myasthenic crisis or mortality. The postoperative pain grade at the first and second follow-ups did not significantly differ between the two groups after the IPTW (P=0.376 and P=0.109, respectively). Conclusions: RATS offered the advantages of improved postoperative QOL according to nursing care systems compared to VATS.