Single-port combined subsegment resection (RS3b+S1bi) with a rare branching segment pattern of the bronchi and vessels: case report and literature review

Background: Video-assisted thoracoscopic surgery segmentectomy is increasingly being used to resect peripheral small lung cancer. However, to manage some lesions which locate between segment deep inside the parenchyma is still challenging. Generally, wedge resection and segmentectomy are optional for peripheral small lung cancer. However, it is hard to achieve safe surgical margins if the lesion is located in the segment plane deep inside the parenchyma, especially close to the segment hilum. In that situation, lobectomy and bi-segmentectomy are usually performed for the sake of safe margins with the price of excessive normal lung tissue lost. To ensure safe surgical margins and preserve normal lung tissue as far as possible, combined subsegmentectomy is feasible and it is required precise preoperative plan including surgical margin delineation, bronchi and vessels variation and surgical procedure. The variation of bronchi and segment vein in our current case are rare and the branching pattern of pulmonary artery-inferior trunk (Tr.inf) is firstly reported in our case. Case Description: In 2019, a 41-year-old female presented to the Thoracic Clinic with a history of a 7-mm sized, mixed-density ground-glass opacity (GGO) in the right upper lobe. The lesion located in the segmental plane between S3b and S1b deep inside the parenchyma. We performed precise preoperative planning with 3-dimension pulmonary bronchi and vessels reconstruction and resected RS3b + S1bi via single-port approach. The patient was discharged from hospital on the 5th postoperative day without any complications. Chest CT scans in the 12th and 24th months after surgery showed good lung recovery, and no atelectasis or pulmonary congestion was observed. Notably, we observed a new branching pattern of A1b, which came from the inferior trunk, combined with A3a. Additionally, we performed a literature review to analyze the variation patterns of segmental structures in the right upper lobe, and the indications, effects, and safety of combined subsegmentectomy. Conclusions: Our case and review of literature showed that combined subsegmentectomy was feasible for lesion deep inside parenchyma if a detailed preoperative plan and delicate procedures during surgery were implemented.