Patient Selection
A retrospective analysis was performed, a total of 55 consecutive patients who underwent tubeless uniportal thoracoscopic wedge resection between August 2018 and December 2019 were retrospectively evaluated(Tubeless Group). Patients in both group underwent non-intubated anaesthetic. The first tubeless uniportal thoracoscopic wedge resection was performed in March 2018, the first non-intubated uniportal thoracoscopic wedge resection with chest tube drainage was performed in January 2017, and the initial 30 cases were not included due to the learning curve effect, a total of 211 patients were included in control group(Drainage Group). Consultants in our department all agreed that either technique was suitable for each patient. Cases with conversion to tracheal intubation, thoracotomy or lobectomy were excluded.
Patients considered appropriate for this technique met the following criteria: single peripheral pulmonary nodule fit for wedge resection(pure GGOs or GGOs with a solid component, distance from visceral pleura within 2 cm), age 18-65, no cardiopulmonary dysfunction, American Society of Anaesthesiologists(ASA) grade of I-II. Patients with a bleeding disorder, sleep apnea, evidence of potential pleural adhesion, overweight(BMI>28), and potential difficult airway for intubation were considered unsuitable(Figure 1). The control group consisted of patients who met the same inclusion and exclusion criteria who underwent the same anesthesia and surgical procedures but with postoperative chest tube drainage.
The application of this new technique was approved by the institutional review board at Nanjing Chest Hospital(number of the ethics approval: 2017-KL002-02), all patients provided written informed consent before operation.
Anaesthesia method
Anaesthesia protocol was described previously(4). In brief, after intravenous infusion of dexmedetomidine 1ug/kg by pump injection within 15min, anesthesia was induced with intravenous dexamethasone 10.00mg, midazolam 0.10 mg/kg and sufentanil 0.1-0.2 µg/kg, target plasma concentration of propofol 2-3µg/ml was controlled by target-controlled infusion(TCI). Pre-lubricated laryngeal mask was inserted for spontaneous ventilation with 100% inspired oxygen (4-5 L/min) to keep oxygen saturation above 95%.
Intercostal nerve block was performed with 0. 375% ropivacaine and 1.00% lidocaine at the rib space where incision located, it was also performed at both one rib space above and one rib space below. Maintaining of anesthesia was done with TCI of propofol (target plasma concentration of 1-2µg/ml), dexmedetomidine(0.5-1µg/kg/h) and remifentanil(0.1~0.5ug/kg/h). After making the incision and opening the ipsilateral pleura, a gradual and natural collapse of the lung occured during spontaneous ventilation procedures. Thoracic vagus nerve block was performed along vagus nerve beside trachea, about 1cm above azygos vein. 5ml of 2% lidocaine was sprayed on the lung surface under thoracoscopic guidance to help reduce cough reflex induced by thoracoscopic manipulation.
Surgical Technique for Uniportal VATS
The patient was kept in lateral decubitus position. A single incision was performed at the fifth intercostal space along the anterior axillary line. During operation, a 10-mm 30-degree thoracoscope (Karl Storz) and several thoracoscopic instruments were simultaneously fitted into the uni-port. PPN was localized by preoperative CT-guided localization with hook-wire when necessary. Wedge resection was achieved using an articulating endoscopic linear cutter(Ethicon or Covidien). Lymph node sampling was performed for PPN containing invasive component(minimal invasive adenocarcinoma or invasive adenocarcinom).
Modified Air Leak Test and Chest Tube Drainage in Tubeless Group
At the end of operation, the lung was immersed in saline and expanded fully for air leak test, the airway pressure was up to about 20 cmH2O, which was assisted by hand controlled ventilation through laryngeal mask(Figure 2A).
After saline was sucked out, a 22-24F chest tube was inserted at the top of thoracic cavity(Figure 2B), and patients was changed to reverse trendelenburg position with 30 degree(Figure 3). Chest tube was placed at posterior one-third position of incision, serratus anterior muscle was interrupted sutured with one suture around chest tube left untied. Then chest tube was connected to a water-sealed bottle, and the lung was expanded again by hand controlled ventilation as before(Figure 2C). When air leak excluded, chest tube was slowly removed, usually 5cm after at least one full breath. The last suture was tied at the same time that chest tube left the thoracic cavity. Then incision was closed with continuous sutures(Figure 2D).Chest tube drainage would be remained in patients with any air leak during this test were .
Chest Tube Insertion and Remove in Drainage Group
One 22F chest drain was inserted to thoracic cavity at the end of the operation, it was placed at posterior part of the uniportal incision. Drain removal criteria were as follows: no observed air leak and total drainage less than 200ml in 24 hours; normal chest roentgenograph; normal vital signs; good overall medical status. No patient was discharged with a chest tube in situ.
Postoperative Treatment and Follow-Up
Chest radiography was performed 6 hours and the following morning post-operatively in tubeless group(Figure 4), it was performed at the first day postoperatively and every 3 days until discharge in drainage group. Drinking and meal intake were resumed after bowel sounds returned with no nausea or vomiting.
The size of residual pneumothorax was defined as the largest distance between the pleural line and the chest wall on chest radiography. Intervention(Chest tube drainage or needle aspiration) should be performed when the size was larger than 3cm. Subcutaneous emphysema was defined as the presence of subcutaneous air on chest radiography. Residual pleural effusions were defined as blunting of the costophrenic angle in the ipsilateral lung on chest radiography.
Postoperative wound pain was monitored using the Visual Analogue Scale (VAS), where 0 indicates no pain and 10 indicates the worst possible pain. VAS was evaluated on postoperative days 1, 3,7, 30 and 60. Wound healing was evaluated by the surgeon one-month after operation, it was graded as satisfactory, unsatisfactory, and debridement required.
Statistical Analysis
SPSS 16.0 for Windows (IBM, Armonk, NY) was used for analysis. To minimize the impact of potential confounders and selection bias, propensity score analysis was used to compensate for the differences in baseline patient characteristics between the two groups of patients. Patients in the two groups were 1:1 matched using the nearest propensity score on the logit scale. Variables that could influence the outcomes of treatment were matched, including age, gender, body mass index (BMI), ASA status class, and maximal lesion size. After PSM, differences in continuous and categoric clinical characteristics were compared.
Continuous data are presented as mean and SD and were analyzed with two-sample Student’s t tests for independent data. Categorical variables are given as a count and percentage of patients and analyzed with the χ2 or Fisher’s exact test. All tests were two-sided, P-values <0.05 were considered statistically significant.