Clinical information
352 patients with NSCLC treated by minimally invasive surgery completed consecutively by the same operator in the Department of Thoracic Surgery of Gansu Provincial People's Hospital from October 2019 to October 2022 were selected. Inclusion criteria: (i) 18 to 80 years old, preoperative examination and assessment of cardiopulmonary function to tolerate surgery; (ii) clear diagnosis of NSCLC by preoperative tracheoscopy, CT-guided puncture biopsy or intraoperative rapid cryopathological examination. Exclusion criteria: (i) intraoperative finding of pleural dissemination; (ii) different operators or assistants.
Surgical Methods
RATS group: The patient was intubated with a double-lumen trachea, under intravenous inhalation compound general anesthesia, and the healthy side was ventilated with one lung, in the healthy side position, with the chest padded and both upper extremities flexed in the pillow-folding position to lower the shoulder and hip to avoid mechanical compression. The da Vinci robot is loaded and punched using the three-arm, four-hole method. In the early stage, our center adopted the 5-7-8-8 perforation strategy, that is, the mirror hole was placed in the 8th intercostal space in the mid-axillary line or the posterior axillary line, and the remaining two operating holes were placed in the 8th intercostal space in the scapular line and the 5th intercostal space between the anterior axillary line and the mid-clavicular line, respectively, and the corresponding operating hole was selected according to the location of the lesion, and the auxiliary operating port was performed in the 7th intercostal space in the mid-axillary line with a 3–4 cm incision. The lateral anterior approach 3-4-6-8/9 perforation strategy was also used, i.e. the mirror hole was placed at the 6th intercostal space in the posterior axillary line, the remaining two operating holes were placed at the 8th/9th intercostal space in the posterior axillary line and the 3rd intercostal space in the anterior axillary line, and the auxiliary operating port was placed at the 4th intercostal space in the midclavicular line. Surgery begins with freeing the inferior pulmonary ligament, depending on the development of the pulmonary fissures, anatomical if the fissures are well developed, or unidirectional lobectomy if the fissures are poorly developed. The hilum (groups 10 and 11) and mediastinal lymph nodes (left side: groups 5, 6, 7, 8, and 9 lymph nodes; right side: groups 2, 4, 7, 8, and 9 lymph nodes) were cleared after successful resection of the diseased lung lobes, as Fig. 1, Fig. 2. Postoperatively, one or two drainage tubes were left in place.
VATS group: The patient was intubated with double-lumen trachea, intravenous inhalation compounded with general anesthesia, and the healthy side was ventilated with one lung, in the healthy side lying position with both upper limbs flexed and holding the pillow in the folding knife position. Generally, a 1.2 cm incision in the 7th or 8th intercostal space in the mid-axillary line is used as the access hole, and a 3 cm incision in the 4th or 5th intercostal space in the anterior axillary line is used as the operating hole.
Detection Of Inflammatory Markers And Lymphocyte Subsets
Blood samples of patients were collected at 4 time points: venous blood of upper limbs was collected on an empty stomach 1 day before operation and 1, 3 and 5 days after operation. Patients were tested for inflammatory markers (CRP, IL-6) and lymphocyte subsets (CD3+, CD4+, CD8+, CD4+/CD8+), and all blood samples were done by the same technicians in the laboratory department of our center.
Observed Indicators
Gender, age, BMI, smoking history, underlying disease, tumor size, surgical procedure, resection site, pathological type, T-stage, N-stage and TNM-stage. Perioperative indicators included operative time, intraoperative bleeding, total postoperative chest drainage, postoperative chest drainage time, postoperative hospital stay, number of lymph nodes cleared, number of lymph nodes cleared stations, postoperative complications, intermediate chest opening, hospital costs, levels of inflammatory markers (CRP, IL-6) and lymphocyte subsets (CD3+, CD4+, CD8+, CD4+/CD8+).
Statistical analysis
A 1:1 PSM analysis was performed using SPSS 26.0 software(SPSS Inc., Chicago, IL, USA), and the caliper value was set at 0.02. Matching factors included gender, age, BMI, smoking history, underlying disease, tumor size, surgical procedure, tumor site, pathological type, T-stage, N-stage, and TNM-stage. Continuous variables were expressed as mean ± standard deviation (‾x ± s), and two independent samples t-test was used for comparison between groups. Categorical variables were expressed as frequencies and percentages (%), and group comparisons were made using the chi-square test or Fisher test. P < 0.05 was considered a statistically significant difference.