Surgical Technique on Robotic Thoracic Surgery Robotic pulmonary segmentectomy

Lung cancer is responsible for approximately 154,000 deaths in 2018 and an estimated 142,000 deaths in 2019 making it the leading cause of cancer related mortality in the United States (1,2). Among these, approximately only one-third of patients present with early stage disease that is amenable to surgical excision, this number increasing secondary to increased lung cancer screening (3). Pulmonary segmental resection offers a lung preserving alternative technique especially critical for patients with emphysema. This technique was first introduced in 1939 by Churchill and Belsey for the treatment of bronchiectasis (4). Despite this early introduction, pulmonary lobectomy continued to be the standard of care for stage I and II lung cancer and was further validated in 1995 by Ginsberg et al. who reported concerning results of increased local recurrence rates and a 30% increase in mortality with segmentectomy (5,6). Since then, multiple studies have demonstrated equivalent outcomes for segmental resection without compromise in survival or recurrence when compared to lobectomy. One prospective, randomized, multi-institutional trial conducted by the Cancer and Lymphoma Group B included 697 patients from 2007 to 2013 with T1N0 peripheral tumors smaller than 2 cm and non-small cell pathology. Early results have been promising, with similar outcomes for patients randomized to lobectomy versus segmentectomy (7). In addition, multiple retrospective studies have shown equivalent disease-free survival and similar recurrence rates (8-18). Okada et al. also noted that the extent of removed lung parenchyma directly affected postoperative functional loss even at 6 months after surgery and segmentectomy offered significantly better functional preservation (15). This data has allowed segmentectomy to become a reasonable alternative, with no compromise to oncologic survival and the advantage of sparing more viable parenchyma compared to standard lobectomy. Anatomical pulmonary segmentectomy requires meticulous intraparenchymal dissection to expose the segmental bronchus and vessels. Open technique was gradually replaced by more minimally invasive techniques, with video-assisted thoracoscopic (VATS) seen to have comparatively excellent results in morbidity, rates of locoregional recurrence, and cancer-free survival compared to standard open technique (19-23). Robotic-assisted techniques were introduced at the end of the 1990s, the first series published for robotic lobectomy in 2002 (24). Few prior studies have examined robotic segmentectomy, the first a multicentric study reporting on 17 patients from 2008 to 2010 followed by Toker et al. in 2014 reporting on 21 patients (25-27). These early studies have concluded that robot-assisted thoracoscopic segmentectomy is safe and associated with few complications, short hospitalization, and oncologically acceptable lymph node harvest. However, no prospective studies have been performed comparing robotassisted to video-assisted thoracoscopic segmentectomy. Musgrove e t a l . compared the ir ear ly robot ic segmentectomy experience with VATS segmentectomy in their single institution retrospective analysis (28). The median length of stay was 2 days with robotic approach as compared to 4 days with VATS and although patients in the robotic group had inferior pulmonary function, they had fewer post-operative complications. Additionally, Liang et al. performed a meta-analysis comparing outcomes of robotic lobectomy and segmentectomy with videoassisted lobectomy and segmentectomy. They showed Surgical Technique on Robotic Thoracic Surgery