Learning curve and outcomes of young surgeons in uniportal video-assisted thoracoscopic surgery lobectomy using bent-tip thoracoscopic forceps for lung cancer

Introduction

Background

Uniportal video-assisted thoracoscopic surgery (VATS) wedge resection was first reported in 2004 (1). Uniportal VATS lobectomy have also been reported in 2013 (2). Bourdages-Pageau et al. has reported that uniportal VATS lobectomy was associated with fewer pneumonias, as well as decreased intraoperative bleeding, faster surgery, shorter duration of chest tube drainage, and shorter hospital stay compared with multiportal VATS lobectomy (3). Uniportal VATS is becoming a widely accepted procedure in Asia and Europe.

Rationale and knowledge gap

It has been reported that the uniportal VATS lobectomy technique can be performed safely from experienced surgeons without major complications and with an acceptable mortality rate (4). Besides, training in a high-volume center allows surgeons to reach expert level faster (5).

However, there are few reports of learning curve that young surgeon performed uniportal VATS lobectomy (6).

Besides, a suction instrument held by the surgeon’s nondominant hand is generally required in uniportal VATS. On the other hands, countertraction with forceps is often needed for peeling off a vessel sheath. Although we use bent-tip thoracoscopic forceps to keep precise of surgery (7), there are no reports about the results of technique.

Objective

This study aimed to address the gap in the literature by investigating perioperative outcomes that young surgeons performed uniportal VATS lobectomy using bent-tip thoracoscopic forceps in NHO Hokkaido Cancer Center and comparing perioperative outcome between uniportal VATS lobectomy and multiportal VATS lobectomy by young surgeons. In addition, we aimed to investigate the learning curves that young surgeons performed uniportal VATS lobectomy. We present this article in accordance with the STROBE reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-794/rc).

Methods

Ethical statement

This study retrospectively reviewed consecutively the records of patients who underwent VATS lobectomy for lung cancer which young surgeons performed at a single center, Hokkaido Cancer Center in Sapporo, Japan, between January 2017 and December 2023. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. The study was approved by the ethics committee of Hokkaido Cancer Center (approval No. 05-04, date of approval: December 25, 2023), and individual consent for this retrospective analysis was waived. Instead, an opt-out notice was posted on the hospital website to provide patients with the opportunity to decline participation.

Patient selection

We define a young surgeon as one who is in their post-graduation years 5 through 10. Three post-graduate year 7 surgeons trained in uniportal VATS lobectomy at NHO Hokkaido Cancer Center. Records were retrospectively obtained from a prospectively maintained database to investigate perioperative outcomes in January 2024. All consecutive patients with primary lung cancer who underwent lobectomy performed by young surgeons between January 2017 and December 2023 were included in this study, excluding those who underwent wedge resection, bilobectomy, or pneumonectomy. Cases involving senior surgeons or simultaneous segmentectomy and lobectomy were excluded. We compared patients undergoing 3-port VATS between January 2017 and December 2021 with those undergoing uniportal VATS between January 2022 and December 2023. During the earlier part of the study period, all young surgeons performed multiportal VATS lobectomy, whereas during the later part of the study period, all young surgeons performed uniportal VATS lobectomy. Patients were thus assigned to the multiportal or uniportal groups according to the surgical approach used in the respective period.

Four young surgeons performed 3-port VATS, while three performed uniportal VATS. Before the study, all young surgeons had performed fewer than 100 multiportal VATS lobectomies and segmentectomies but had no prior experience with uniportal VATS. Specifically, surgeon A had performed 72 lobectomies and 20 segmentectomies, surgeon B had performed 58 lobectomies and 9 segmentectomies, and surgeon C had performed 37 lobectomies and 9 segmentectomies. Surgeries were conducted under supervision from senior surgeons with extensive experience in both techniques.

Lung cancer was diagnosed through computed tomography (CT), magnetic resonance imaging (MRI), ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET), and bronchoscopy with biopsy. Our team of surgeons with reference to opinions of oncologists and radiologists staged the disease on tumor-node-metastasis (TNM) classification of malignant tumors (eighth edition), and was performed according to the World Health Organization classification (8). Young surgeons exclusively operated on cases without bulky lymph nodes under appropriate supervision. Senior surgeons decided conversion to thoracotomy when they thought that it was difficult to proceed surgery. Since adding additional ports was not expected to resolve the technical difficulties, direct thoracotomy was chosen to ensure adequate exposure and safety.

Operative procedure

Operative procedures were performed with the patient in the lateral decubitus position under general anesthesia with double-lumen intubation. In 3-port VATS, a 3- to 4-cm operator’s port was made in front of the anterior line of the latissimus dorsi muscle on the posterolateral incision line (basically within the fourth or fifth intercostal space, depending on patient’s body) (Figure 1A). A protective film and ring device for protecting the wound was used. A 5-mm thoracoscope port was inserted in the mid-axillary line (almost in the sixth intercostal space, at a point that looks down the major fissure, sometimes more caudally). A 2-cm assistant’s port was made at a posterior location on the same line (almost in the seventh intercostal space). In 3-port VATS, standard instruments and techniques were used, including vessel-sealing or electrocautery devices, forceps, and staplers, under visualization with a 30-degree thoracoscope.

Figure 1 Port placement. (A) 3-port VATS. (B) Upper lobe and middle lobe in uniportal VATS. (C) Lower lobe in uniportal VATS. VATS, video-assisted thoracoscopic surgery.

In uniportal VATS, a single 3- to 4-cm wound was made between anterior axillary line and middle axillary line in the fourth intercostal space for upper lobectomy or middle lobectomy (Figure 1B). The wound for lower lobectomy was made in the mid-axillary line in the fifth intercostal space (Figure 1C). The connected cotton swab technique (9) and smoke ventilation method (10) were employed to stabilize the lung and secure the operative field. We standardized our procedure to routinely use the bent-tip thoracoscopic forceps in all cases, as we considered it essential for safe dissection and countertraction (7). Several key technical tips for uniportal VATS lobectomy are shown in Figure 2, and a representative case is presented in Supplementary file (Video 1). Postoperative complications were defined by the Clavien-Dindo classification (11).

Figure 2 Key tips for performing uniportal lobectomy. (A-C) 3 tips to perform uniportal VATS right upper lobectomy. (A) First, before dissecting the superior trunk, the area adjacent to the superior vena cava and beneath the azygos vein should be carefully dissected. (B) Second, the cranial and dorsal aspects of the upper lobe bronchus should be thoroughly cleared. (C) Third, meticulous dissection of V1–3 and A5 is essential. Once this is completed, V1–3 can be easily encircled. (D) To achieve a better surgical view, left upper mediastinal lymphadenectomy was performed prior to commencing the left upper lobectomy. (E,F) To achieve a better surgical view, during carinal lymphadenectomy, dissection was first carried out around the esophagus and the contralateral main bronchus. (E) shows the dissection in the right thoracic cavity. (F) shows the dissection in the left thoracic cavity. VATS, video-assisted thoracoscopic surgery.

Statistical analysis

All statistical analyses were performed with EZR (Saitama Medical Center, Jichi Medical University, Saitama, Japan), a graphical user interface for R (The R Foundation for Statistical Computing, Vienna, Austria). This software is a modified version of R commander with additional biostatistics functions.

Continuous variables were assessed for distribution. Variables are presented as median (minimum, maximum) and were compared using the Mann-Whitney U test. Categorical variables are presented as numbers (percentages) and were compared using the Chi-squared test or Fisher’s exact test, as appropriate. A P value <0.05 was considered statistically significant.

Because this was not a prospective randomized controlled trial, differences in background characteristics between the uniportal and 3-port VATS groups were expected. To reduce selection bias, propensity score matching was performed using logistic regression. Variables entered into the model included age, performance status, Brinkman index, clinical stage (stage II or higher), extent of lymph node dissection, and tumor lobe location. Patients were matched 1:1 between the two groups using the nearest-neighbor method without replacement and with a caliper of 0.2 of the standard deviation of the logit of the propensity score. After matching, operative time, blood loss, number of lymph nodes dissected, lymph node upstaging, and postoperative complications were compared between the groups.

Uniportal VATS outcomes were analyzed for each trainee individually using the cumulative sum (CUSUM) method. Operative time was plotted against the cumulative sum for each trainee to visualize learning curves. As procedural familiarity improved, operative times should pass over the peak of the curve.

Results

A total of 490 patients underwent VATS lobectomy for lung cancer. After excluding cases performed by senior surgeons (n=274) and simultaneous segmentectomy (n=1), 215 patients were included (Figure 3). Uniportal VATS was performed for 95 patients, and 3-port VATS for 120 patients.

Figure 3 Flow chart of patient selection in this study. VATS, video-assisted thoracoscopic surgery.

Patient characteristics are summarized in Table 1. Significant differences between the uniportal and 3-port groups were observed in age (median 72 vs. 70.5 years, P=0.03), tumor size (28 vs. 25 mm, P=0.007), and extent of lymph node dissection (ND2a-1: 89.5% vs. 59.2%, P<0.001). Operative and postoperative outcomes also differed significantly. The median operative time was 168 minutes (range, 57–302 minutes) for uniportal VATS compared to 234 minutes (range, 105–561 minutes) for 3-port VATS (P<0.001). The median intraoperative blood loss was 7 g (range, 1–105 g) in the uniportal group versus 16 g (range, 1–322 g) in the 3-port group (P<0.001). The conversion rate to thoracotomy was 1% (1/95) in the uniportal group and 8.3% (10/120) in the 3-port group (P<0.001). Reasons for conversion in uniportal VATS were limited to one case of infiltrated lymph nodes, whereas in 3-port VATS, reasons included infiltrated lymph nodes (4 cases), pleural adhesion (1 case), and dissection difficulty (5 cases).

The total number of lymph nodes dissected was 14 vs. 14 (P=0.67), the number of mediastinal lymph nodes dissected was 7 vs. 6.5 (P=0.54), and pathological nodal upstaging from clinical nodal stage was 9.5% vs. 15.1% (P=0.30), showing no significant differences between groups.

Postoperative complications (Clavien-Dindo grade ≥ III) occurred in 11 (11.6%) uniportal VATS patients and 8 (6.7%) 3-port VATS patients. In uniportal VATS, complications included pleurodesis for prolonged air leak or pneumothorax (7 cases), pyothorax (2 cases), and chylothorax (2 cases). No postoperative mortality was observed. In the 3-port group, complications included pleurodesis for prolonged air leak or pneumothorax (4 cases), massive pleural effusion (2 cases), chylothorax (1 case), and one mortality due to acute exacerbation of interstitial pneumonia.

Propensity score matching balanced most clinical variables between groups (Table 2). Matched comparisons confirmed significant differences in operative time, bleeding, and conversion rates, but no differences in postoperative complications, lymph node dissection, or pathological nodal upstaging. The CUSUM graph for operative time revealed transition points between cases 7 and 14, indicating a learning curve for young surgeons (Figure 4).

Figure 4 CUSUM curves for operative time of patients who had undergone uniportal VATS lobectomy for surgeon A (n=17) (A), surgeon B (n=40) (B), and surgeon C (n=38) (C). The y-axis shows the CUSUM of the difference between each operative time and the mean operative time. It does not represent the actual operative time in minutes. The arrowhead indicates the CUSUM peak (turning point of the learning curve). CUSUM, cumulative sum; VATS, video-assisted thoracoscopic surgery.

Discussion

Key findings

This study evaluated perioperative outcomes of uniportal VATS lobectomy performed by young surgeons using bent-tip thoracoscopic forceps, in comparison to conventional multiportal VATS lobectomy. It also assessed the learning curve using the CUSUM method. Significant differences were observed in operative time, intraoperative blood loss, and conversion rates. Oncological outcomes such as the number of dissected lymph nodes, mediastinal lymphadenectomy, and nodal upstaging rates were comparable between the two groups, indicating that oncological integrity was preserved with the uniportal approach. The learning curve analysis revealed earlier proficiency than previously reported, suggesting the effectiveness of the bent-tip thoracoscopic forceps and structured training protocols. In this study, the number of mediastinal lymph nodes dissected tended to be higher in the uniportal VATS group after propensity score matching (median 7 vs. 6.5, P=0.053). Although this was not statistically significant, it may indicate that the uniportal approach with bent-tip thoracoscopic forceps allowed young surgeons to perform mediastinal lymphadenectomy more easily and precisely. This finding suggests that oncological thoroughness was preserved, when uniportal VATS was performed with bent-tip forceps, even in the hands of less experienced surgeons. However, since no control group without bent-tip forceps was available, the exact magnitude of this benefit could not be quantified.

Strengths and limitations

A major strength of this study is the use of the CUSUM method to quantitatively evaluate the learning curve, providing objective insights into surgical proficiency development. Propensity score matching was also employed to reduce potential selection bias. However, this study is limited by its retrospective design and single-center setting design, which may affect the generalizability of the findings. In addition, all uniportal VATS cases in this study were performed using bent-tip thoracoscopic forceps, which we consider essential for safe and precise dissection. While their use may have contributed to improved efficiency and a shorter learning curve, the independent effect of this instrument could not be directly assessed because no control group without bent-tip forceps was available.

The lack of randomization also remains a methodological limitation. Future prospective and multi-center studies are necessary to validate these results. However, only operative time was analyzed in this CUSUM assessment; future analyses should also incorporate complication rates and length of stay.

Comparison with similar research and explanations of findings

The study demonstrated significant differences in operative time, bleeding, and conversion rates between uniportal and multiportal VATS lobectomy. The reduced operative time and blood loss observed in Uniportal VATS are likely due to several factors, including the smaller number of incisions, faster opening and closing, fewer hemostatic points, minimized instrument exchanges through the predominant use of energy devices like vessel sealing devices, and the adoption of a systematic surgical procedure specifically optimized for Uniportal VATS, facilitating more efficient operations. Additionally, using the camera arm might have not been easy in 3-port VATS. The lower conversion rate to thoracotomy suggests that uniportal VATS is both feasible and safe when performed under appropriate supervision, even for less experienced surgeons.

Oncological outcomes, including the number of lymph nodes dissected, mediastinal lymphadenectomy, and nodal upstaging rates, were comparable between the two groups, indicating that oncological integrity was maintained with uniportal VATS. Although the uniportal group had a slightly higher complication rate, these complications were manageable and consistent with previous reports (4,5,12). On the other hand, the lymph node upgrading rate was slightly higher in the 3-port VATS group. This rate was higher than that of the previous report despite the high rate of ND2a-1 (13). This is presumed to be due to the renewal of FDG-PET at NHO Hokkaido Cancer Center in October 2018, which improved the accuracy of diagnosing clinical lymph node metastasis.

The learning curve analysis using CUSUM revealed transition points between cases 7 and 14, which is earlier than previous reports suggesting 14 to 26 procedures (14,15). This may underscore the effectiveness of bent-tip thoracoscopic forceps and structured training protocols in achieving proficiency more efficiently. The bent-tip forceps facilitated precise dissection, reducing the need for countertraction instruments and contributing to improved efficiency. Standardized procedural steps also helped overcome technical challenges during early training phases.

Implications and actions needed

These findings support the feasibility and safety of uniportal VATS lobectomy performed by young surgeons when adequate supervision and structured training are provided. The results emphasize the value of bent-tip thoracoscopic forceps and standardized procedural approaches in surgical education. To strengthen the evidence, future studies should include randomized, prospective, and multi-center designs. Recent reports of initial outcomes with uniportal VATS also support its feasibility and safe introduction into surgical practice (16). In addition, further refinement of training protocols may help reduce complication rates and facilitate broader adoption of uniportal VATS.

Conclusions

Uniportal VATS lobectomy using bent-tip thoracoscopic forceps, performed by young surgeons with less than 10 years of postgraduate experience, demonstrated comparable oncological effectiveness and safety to multiportal VATS lobectomy. The learning curve, as shown by CUSUM analysis, indicated that mastery could be achieved efficiently. Further multi-center studies with larger cohorts are necessary to validate these findings and optimize training strategies for young surgeons.

Acknowledgments

The authors would like to acknowledge all the staff involved in the care of the patients in the Department of Thoracic Surgery, NHO Hokkaido Cancer Center.

Footnote

Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-794/rc

Data Sharing Statement: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-794/dss

Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-794/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-2025-794/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 Hokkaido Cancer Center (approval No. 05-04, date of approval: December 25, 2023), and individual consent for this retrospective analysis was waived. Instead, an opt-out notice was posted on the hospital website to provide patients with the opportunity to decline participation.

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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