Non-intubated uniportal video-assisted thoracoscopic anatomical lung volume reduction surgery—an institutional report

Introduction

During the past decades, video-assisted thoracoscopic surgery (VATS) has gained widespread acceptance as standard approach for anatomic lung resection in thoracic surgery. It was first described as multiportal technique for lobectomy in lung cancer back in 1992 by Roviaro (1), before Gonzalez introduced a uniportal approach in 2011 (2).

An ongoing trend towards continuously reducing invasiveness in thoracic surgery has led to an increasing adoption of non-intubated VATS under spontaneous respiration (3,4). This concept of conducting thoracic procedures under spontaneous ventilation has a storied background, and was first described by Sir Francis Richard Cruise in 1865 for thoracoscopy (5) and later applied to open thoracotomy by Alexander Wischnewski in 1954 (3). As technical advances in thoracic surgery came alongside advances in anesthesia, especially the implementation of double-lumen tubes or blocker catheters for one-lung ventilation, VATS was almost exclusively performed under mechanical ventilation until Gonzalez-Rivas reported his first non-intubated uniportal VATS (niuVATS)-lobectomy in 2014 (6). Since then, a large number of thoracic procedures under spontaneous ventilation have been reported, in the case of major pulmonary resection mostly by Asian centers (7). They include diagnostic resections in interstitial lung disease (ILD) (8), lung volume reduction surgery (LVRS) for emphysema (8), or decortication for empyema thoracis and mediastinal tumor excisions (9). Reported advantages of non-intubated surgery span from avoidance of intubation-related airway trauma, ventilation-induced lung injury, and residual neuromuscular blockade to decreased drug-related post-operative nausea and vomitus, and spontaneously breathing patients will benefit from an efficient contraction of the dependent hemidiaphragm and preservation of hypoxic pulmonary vasoconstriction in surgically induced pneumothorax required for niuVATS (10). Oxygenation can usually be maintained in niuVATS major lung resection surgery, even in patients with impaired respiratory function, despite relative hypoventilation; mild hypercapnia is inevitable but clinically well tolerated (9). In ILD patients, a specific form of procedure-related acute exacerbation can ensue due to mechanical ventilation, and a high positive end-expiratory pressure is associated with decreased survival (8), further encouraging avoidance of mechanical ventilation in these patients.

Despite an increasing interest in this approach, at present only one publication with limited numbers looked into the feasibility of major pulmonary resection in severely impaired patients (11). This prompted us to look up our institutional experience and report it. We present this article in accordance with the STROBE reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1598/rc).

Methods

This study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Ethics Committee of the Hannover Medical School (No. 11591_BO_K_2024) and individual consent for the retrospective analysis was waived. We then investigated the records of Hannover Medical School to collect preoperative patient characteristics, surgical details, pre- and postoperative lung function data, postoperative course, and complications for all patients that underwent niuVATS major pulmonary resection between May 2018 and May 2022. Based on this we further analyzed patients to identify those with impaired lung function [predictive postoperative % of forced expiratory volume in 1 second (ppoFEV1%) <35%]. Patient information, including age, gender, body mass index (BMI), smoking history (including pack-years), American Society of Anesthesiologists (ASA) classification, preoperative oxygen therapy, and surgical indications, was documented. All patients underwent preoperative lung function tests, including the measurement of diffusion capacity for carbon monoxide (DLCO), along with conventional chest X-rays and computed tomography (CT) scans. For patients with chronic obstructive pulmonary disease (COPD) undergoing LVRS, preoperative phase-resolved functional lung (PREFUL) magnetic resonance imaging (MRI) (12) was additionally performed to identify the most appropriate resection site.

Indications for anatomical niuVATS-resection included LVRS for COPD and curative treatment for primary lung cancer. We previously described our anesthesiologic management in major niuVATS surgery elsewhere (3): our standard monitoring includes electrocardiogram (ECG), non-invasive blood pressure measurement, pulse oximetry, respiratory rate, and approximation of end-tidal carbon dioxide monitoring (etCO₂). All patients received 1–2 peripheral intravenous lines (> G18). During the procedure, oxygen (4–8 L/min) was applied via face mask or laryngeal mask, allowing sampling of exhaled carbon dioxide in non-intubated patients during administration of supplementary oxygen. Oxygen supplementation was adjusted to keep the saturation of peripheral oxygen (SpO₂) above 92%. To prevent coughing from hilar manipulation and lung traction, 3 mL of 2% lidocaine was nebulized before induction and immediately prior to surgery (Flexicare Dual Mask™, Flexicare Medisize, Germany; Aeroneb Pro X™, WKM GmbH, Mönchengladbach, Germany). An intrathoracic vagal nerve block with 2–5 mL of 0.5% ropivacaine was performed in all patients.

Thoracic epidural analgesia (TEA) was provided with a catheter inserted at T4–T5 in the sitting position. After a 3 mL test dose of 0.5% bupivacaine, 8–10 mL of 0.2% ropivacaine and 10 µg sufentanil were administered to achieve adequate sensory block while preserving diaphragmatic movement. Patient-controlled epidural analgesia was delivered via an automated pump (CADD™, Smiths Medical, Kent, UK).

Sedation was maintained with continuous dexmedetomidine infusion (200 µg/50 mL), starting at 3 µg/kg/h for 10 min and titrated to 0.5–1 µg/kg/h. If sedation or analgesia was insufficient, small boluses of sufentanil or propofol were given.

Patients were positioned laterally, and the operative lung was deflated after thoracotomy. In case of desaturation, temporary re-expansion was achieved using a chest tube under suction. Conversion to general anesthesia was performed with propofol (1–2 mg/kg), sufentanil (0.2 mg/kg), and rocuronium (0.5 mg/kg). Anesthesia was maintained with sevoflurane or propofol (5 mg/kg/h) and rocuronium. Airway control was achieved using a double-lumen tube or bronchial blocker (EZ-Blocker™, Teleflex, Fellbach, Germany; Arndt Blocker Set, Cook Medical, Limerick, Ireland) placed under video laryngoscopic or fiber-optic guidance (C-Mac™, KARL STORZ, Tuttlingen, Germany). Criteria for conversion to general anesthesia were severe hypoxemia [partial pressure of oxygen (PaO₂) <60 mmHg], severe hypercapnia with acidosis (pH <7.1), hemodynamic instability, persistent cough in spite of intrathoracic vagal nerve blockade, excessive diaphragmatic/mediastinal movement, failure of regional anesthesia, incomplete iatrogenic pneumothorax, and surgical complications (major bleeding, lack of progress, adhesions, unexpected situs). The procedures were performed through a single 3 cm incision located in the 4^th interspace in the medio clavicular line through a soft tissue retractor (SurgiSleeve size S, Medtronic, Minneapolis, MN, USA), and visualization was realized through a 10 mm/30° Video-System (EndoEye, Olympus Germany, Hamburg, Germany). After intrathoracic vagal nerve blockade, standard dissection of bronchi and vessels was performed with dedicated surgical instruments for uniportal procedures (Scanlan Surgical, Saint Paul, MN, USA), prior to transecting respective vessels and bronchi with Endo-Staplers (Lexington Medical Inc., Bedford, MA, USA). All patients were subsequently scheduled to recover in the post-anesthesia care unit (PACU) after surgery prior to same-day transferal to the surgical ward. Chest tubes were removed whenever less than 300 mL of fluids/24 h and no air leakage (measured on the Medela Thopaz, Medela AG, Baar, Switzerland) were ascertained.

The laterality, surgical approaches, and specific procedures performed were recorded. Postoperative conditions, such as extubation status, intensive care unit (ICU) stay, chest drainage duration, and time to discharge, were also documented. Operative mortality was defined as death within 30 days or any death occurring during hospitalization. In addition, postoperative lung function was assessed during follow-up visits 4 months or more after the operation. Postoperative morbidity and mortality rates were investigated. Follow-up data were collected from the hospital records. Postoperative outcomes were evaluated by assessing general information and lung function impairments during the follow-up period. The correlations between complications and associated variables were investigated. Considered complications included pneumonia, atelectasis, and persistent air leakage. Associated variables were redo-operation, resected volume, and surgical procedures (segmentectomy or lobectomy). The resected volume was quantified based on the number of resected segments.

Statistical analysis

Statistical analyses were performed using GraphPad Prism 8.4.3 (GraphPad Software, Boston, MA, USA). Student’s t-test and Kaplan-Meier analysis were applied to compare two groups and for survival analysis, respectively. Proportions were compared using χ² tests. P value of less than 0.05 were considered to indicate statistical significance.

Results

Study cohort

We performed anatomical resection via niuVATS in 57 patients during the 4 years. In the cohort, 12 patients underwent their procedure with severely impaired lung function (Figure 1). Indication for resection was COPD in all patients (n=12, 100.0%); i.e., all operations were performed as LVRS for patients with impaired lung function. The average age of the cohort was 65.3±11.9 (range, 43–87) years. Four of these patients were male (33.3%). BMI was 22.5±4.2 (range, 17–33) kg/m². Eleven patients were smokers (91.7%), and their pack-year status was 27.5±17.2. Median of the ASA physical classifications was class 3 (ASA 3: n=11, 91.6%). Two patients underwent the operation as a redo-procedure (16.7%). Five patients needed an oxygen supplementation preoperatively (41.6%). Preoperative capillary gas analyses were 40±4.6 mmHg of CO₂ partial pressure and 71.5±11.3 mmHg of O₂ partial pressure (Table 1).

Figure 1 Study profile. NiuVATS, non-intubated uniportal video-assisted thoracoscopic surgery; VATS, video-assisted thoracoscopic surgery.

Preoperative lung functions

The percentage of the preoperative FEV1% was 30.5%±10.9% and ppoFEV1%: 25.1%±8.9%. The DLCO was 23.0%±10.3%; the forced expiratory flow (FEF) 25–75% was 11.8%±5.2%; and FEV1/forced vital capacity (FVC) was 35.8%±10.6% (Table 1).

Surgical procedures

As reported elsewhere, we generally perform anatomical resection for LVRS (13), and select our target segment(s) or lobe(s) based on functional MRI imaging. All included patients successfully underwent niuVATS without a conversion to either mechanical ventilation and/ or open thoracotomy. Lobectomy was performed in 10 patients (83.3%). The other 2 patients (16.7%) underwent segmentectomy (3-segment resection: S4–6 and S8–10). Operation time was 77.6±26.6 (range, 48–144) min (Table 2).

Postoperative course and early complications

Chest tube duration was 9.1±4.5 (median, 7.5) days, and the discharge from hospital was 12.8±5.0 days after the operation. As early complications, persistent air leakage over 7 days was observed in 6 patients (50.0%). Three patients suffered from atelectasis (25.0%), and 2 patients suffered from pneumonia (16.7%). No patient suffered from empyema or wound infection (Table 3). According to Kaplan-Meier analysis, the 5-year survival rate with the cohort was 73.3% (Figure 2).

Figure 2 Kaplan-Meier curve. Survival proportions after the uniportal niuVATS anatomical resection. NiuVATS, non-intubated uniportal video-assisted thoracoscopic surgery.

Complications and related variables

No significant differences were observed between patients who underwent redo-surgery and those who had a primary operation with regard to overall complications (P=0.19), atelectasis (P=0.37), pneumonia (P=0.17), or persistent air leakage (P=0.12). Furthermore, surgical procedures did not have a significant impact on any of the variables (P=0.79, P=0.37, P=0.17, and P=0.12, respectively).

Patients who experienced complications underwent resections involving 3±0.534 segments, while those without complications had resections involving 3.6±0.8 segments. No significant difference was found between these groups (P=0.12) (Table 4). Similarly, there were no significant differences in the number of resected segments between patients with and without atelectasis (3.33±0.817 vs. 3±0, respectively; P=0.14), pneumonia (3.33±0.781 vs. 3±0, respectively; P=0.14), or persistent air leakage (3.5±0.764 vs. 3±0.577, respectively; P=0.14) (Table 5).

Follow-up at least 4 months after operation

Eight patients were able to be followed and evaluated using hospital records, representing 66.7% of the cohort. Nearly all patients in this group experienced some form of early postoperative complications (n=6, 75%), including one case of atelectasis, two cases of pneumonia, and six cases of persistent air leakage. The mean follow-up time was 21.9±13.1 (range, 5.9–45.7) months. One patient underwent lung transplantation 31.4 months after the operation. Four patients who had preoperative oxygen supplementation were included in the follow-up cohort (80% in preoperative oxygen therapy patients in the whole cohort). Of these, 2 patients continued to require oxygen therapy (50%), while the other two had discontinued it.

A follow-up lung function test was conducted. Preoperative FEV1% was 26.50%±9.62%, and ppoFEV1% was 21.43%±7.13%. There was no significant difference between preoperative and postoperative FEV1% values (26.38%±7.52%; P=0.47). However, between ppoFEV1% and the postoperative FEV1%, there was a significant difference (P=0.003). Also, significant differences were observed in FEV1/FVC and FEF 25–75% between preoperative and postoperative values: FEV1/FVC was 33.88%±11.72% preoperatively vs. 43.88%±13.52% postoperatively (P=0.04), and FEF 25–75% was 9.38%±2.83% preoperatively vs. 11.13%±3.72% postoperatively (P=0.01; Tables 6,7).

Discussion

Minimally invasive thoracic surgery continues to evolve, with the current pinnacle being niuVATS, as suggested by a fair amount of reasonable evidence suggesting that it is less invasive when compared to previous surgical approaches (3,4,6,7). Uniportal VATS, by itself, can be considered as less invasive than multiportal VATS (14), while non-intubated VATS further reduces complications related to general anesthesia and intubation, including airway trauma, ventilation-induced lung injury, postoperative nausea, microaspiration, and atelectasis (3). Additionally, patients can mobilize immediately after surgery, which could potentially reduce stress hormone levels and contribute to an early recovery (15,16). This early recovery, facilitated by a prompt return to activity, is particularly crucial for patients with compromised pulmonary function, as it helps minimize the risk of complications. Preventing pneumonia caused by microaspiration or other factors, as well as minimizing the loss of lung function due to ventilation-induced lung injury, plays a key role in preserving a patient’s general condition.

This cohort consisted of patients with a ppoFEV1% of 35% or less, generally classified as high-risk (17). Although two patients developed pneumonia in our cohort, they responded well to conventional antibiotic treatment. Importantly, no mortality or severe complications occurred in the early postoperative phase, which can be considered an acceptable outcome. Furthermore, during the mid-term follow-up, lung function either stabilized or improved compared to preoperative levels.

However, it should be noted that these improvements could be attributed not just to a niuVATS approach, but to the effects of LVRS. Ever since the National Emphysema Treatment Trial (NETT) reported significant improvements in exercise capacity, 6-minute walk distance, FEV1, and quality of life (QOL) in a subgroup with predominantly apically located emphysema that underwent surgery (18) and a previous study reported similar findings, with improvements in survival, exercise capacity, and QOL in LVRS for heterogeneous emphysema (13), LVRS has become an integral part of managing severe emphysema. Current evidence on niuVATS in patients with severely impaired lung function remains limited and contradictory. While certain groups generally advise against it in severe COPD (19), others appear to support it (4). As previously mentioned, only one publication explicitly looked into non-intubated VATS major pulmonary resection in severely impaired patients (11). As they defined impaired pulmonary function as a predicted FEV1 <60% [in accordance with current American Thoracic Society (ATS) guidelines] and only had a limited number of patients undergoing major lung resection, these results are difficult to compare. Nonetheless, they concluded that non-intubated VATS is just as safe as conventional VATS in pulmonary impaired patients. With just a fraction in both groups having grade III or IV complications based on the Clavien-Dindo classification, the procedures appeared to be associated with limited morbidity. In our cohort, we found that although a relevant portion of our patients had air leaks or atelectasis, major complications did not occur, which corroborates their findings. As mentioned, half of our patients experienced prolonged air leakage (PAL), likely due to underlying COPD and emphysema. We do not routinely apply stapler reinforcement, which could partially explain PAL in this collective; however, the median chest tube duration was 7.5 days, and no infections or other complications occurred. Despite these early complications, the patients’ condition improved during short- to middle-term follow-up. One of the reasons for little to no septicemic complications could be attributed to less cytokine production related to niuVATS (20) and generally faster recovery when foregoing mechanical ventilation and general anesthesia.

Conclusions

While technically challenging for the surgeon, niuVATS currently represents the least invasive form of anatomical lung resection and appears to be safely feasible in patients with severely impaired pulmonary function, leading to acceptable results and no major complications or mortality in selected patients despite a high morbidity in this population group.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1598/rc

Data Sharing Statement: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1598/dss

Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1598/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1598/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the Ethics Committee of the Hannover Medical School (No. 11591_BO_K_2024) and individual consent for the retrospective analysis was waived.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

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