Study design
We designed a retrospective cohort analysis and included patients referred to Tianjin Medical University General Hospital for bronchoscopy between October 2022 and April 2024 who met the following criteria: 1) age ≥ 18 years; 2) CT showed mediastinal or hilar lymph nodes with a short diameter ≥ 1 cm, or PET-CT revealed abnormally increased lymph node metabolism; and 3) the same patient successively completed EBUS-TBNA and EBUS-TDB procedures. The exclusion criteria were as follows:1) heart, brain, kidney, lung, and other important organ dysfunction; 2) coagulopathy and severe blood system diseases; and 3) active bleeding.
Surgical method
Preoperatively, the operated lymph nodes were selected according to imaging findings, and the patients were assessed for adequate anaesthesia. After satisfactory general anesthesia (propofol, 1.5–2.5 mg/Kg, Corden Pharma S.P.A, Ireland) and muscle relaxation (rocuronium bromide injection, 0.6 mg/Kg, Guangdong Jiabo Pharmaceutical Co., Ltd., China), a rigid bronchoscope was placed, and high-frequency jet ventilator ventilation was performed to ensure the patient's blood oxygen and maintain carbon dioxide stability. First,we observed the airways using conventional bronchoscopy (BF-260; Olympus, Tokyo, Japan), and some patients underwent mucosal/lung biopsy or bronchoalveolar lavage. We replaced this with ultrasound bronchoscopy (CP-EBUS; BF-UC26 0F-OL8; Olympus, Japan). The surgeon observed the ultrasound image of the target area, avoided blood vessels and necrotic areas, and selected the soft and elastic parts of the surgical area, such as the tracheal cartilage ring, whenever possible.
Standard Olympus EBUS TBNA 22 G puncture needle (NA - 201SX ‐ 4022; Olympus, Japan) was used to perform EBUS-TBNA for 3–4 consecutive times, about 3 min for each needle, and the total time was about 10–15 min to ensure that the puncture sampling position remained consistent. The specimen was sent to the pathology department after forming a liquid wax block in the cell preservation solution.
After completing EBUS-TBNA, EBUS-TDB was performed using a Maidishi contact laser CFE0.6-SMA fine fibre as a tunnelling and incision tool for surgery. A thin laser fiber was preinstalled in the EBUS endoscope, slightly ahead of the treatment orifice, and the output power was adjusted to 7.5 W. Under the guidance of EBUS, a thin fibre was inserted at the previous EBUS-TBNA puncture imprint, and the fiber tip contacted the mucosal tissue to dissect in layers, creating a full-thickness incision meticulously. This established a tunnel that allowed the passage of 1.8 mm standard biopsy forceps (RXQY-W1216-PA, TIANJINGUANGYUANFUTIAN, China) with a laser tunneling time of about 5 min. The standard biopsy forceps were preloaded into the EBUS endoscope and inserted into the tunnel inlet. The forceps were then passed through the tunnel inlet to penetrate deep into the target area. Samples were taken 4–6 times, with the biopsy procedure lasting approximately 3 min, with a total time of about 8–10 min. The tissues were placed in formalin for preservation and sent to the pathology department.
Intraoperative bleeding was usually controlled by bronchoscopic compression, ice saline, or thrombin (Changchunlei Yunshang Pharmaceutical Co., Ltd., 2000 units). At the end of the procedure, the surgical area was observed to confirm that there were no complications, such as significant bleeding. The rigid bronchoscope was removed, and a laryngeal mask airway was placed and connected to an anaesthesia device for ventilation. The patient was allowed to recover and was monitored in the bronchoscopy resuscitation room for at least 2 h.
Postoperative adverse events
Patients were observed for haemoptysis, fever, hypoxia, arrhythmia, chest pain, dyspnoea, and other symptoms within 24 h after surgery. Body temperature was monitored within 1 week after surgery, and chest CT was performed when necessary.
Pathological diagnosis
The liquid wax blocks and tissues were sent to the pathology department
for dehydration, transparency, wax immersion, sectioning, staining, and sealing of the tissues. Immunohistochemistry was performed according to clinical classification. Pathological diagnoses were made by an attending physician and reviewed by a single consultant.
Criteria for diagnosis
Benign and malignant tumour, lymphoma were diagnosed based on pathological findings; tuberculosis was diagnosed based on pathological findings or etiological examination results, and positive etiological results included any of PCR, GeneXpert, or mNGS tests. The diagnosis of sarcoidosis was based on three major criteria: a compatible clinical presentation, the finding of non-necrotizing granulomatous inflammation in one or more tissue samples, and the exclusion of alternative causes of granulomatous disease [11].
Statistical analysis
IBM SPSS Statistics for Windows, version 26.0 (IBM Corp., Armonk, N.Y., USA) was used for the data analysis. Normally distributed continuous variables are reported as means and standard deviations, and t-tests were used to compare groups. For skewed continuous variables, medians and interquartile ranges were reported, and Wilcoxon rank tests were used. Categorical variables are presented as frequencies and percentages, and chi-square tests were used to analyse the differences between the two groups of data. A p-value of < 0.05 was considered statistically significant.