Comparison of uniportal and three-portal video-assisted thoracoscopic thymectomy for thymoma: a propensity score-matched study
Highlight box
Key findings
• Thymectomy treatment of three-portal video-assisted thoracoscopic surgery (TP-VATS) thymectomy is an advisable procedure for patients with thymoma.
What is known and what is new?
• VATS thymectomy is a validated technology.
• Different thoracoscopic surgical methods could be considered in the selection procedure.
What is the implication, and what should change now?
• The chief surgeon should choose the appropriate surgical method based on personal technical proficiency and the specific situation of the patient.
Introduction
For over a century, median sternotomy has been considered as the standard approach for the anterior mediastinum tumor (1). However, thoracic surgeons are striving to explore the other less invasive approaches because of the significant morbidity associated with median sternotomy approach (2). On account of endeavors for the past decades, there has been a significant increase in the adoption of minimally invasive techniques such as video-assisted thoracoscopic surgery (VATS).
Minimally invasive surgical approaches for thymectomy have gained popularity for patients. A variety of studies suggested that VATS has improved surgical treatment outcomes. VATS has many advantages compared to the traditional thymectomy. VATS thymectomy has been associated with shorter hospital stay, less operative blood loss and decreased postoperative pain (3-7).
To investigate the efficacy of the minimally invasive thymectomy (MIT), a retrospective comparison of perioperative outcomes for patients was conducted between the uniportal and three-portal video-assisted thoracoscopic surgery (UP-VATS and TP-VATS) thymectomy. We retrospectively compared clinical data from patients who underwent the UP-VATS thymectomy or the TP-VATS thymectomy technique. We present this article in accordance with the STROBE reporting checklist (available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1305/rc).
Methods
From January 2013 to December 2022, 323 patients were admitted for surgical assessment from the same medical group in the Department of Thoracic Surgery of The Second Affiliated Hospital of Zhejiang University. The study was conducted in accordance with the Declaration of Helsinki and its subsequent amendments. This study was approved by the Ethics Committee of The Second Affiliated Hospital of Zhejiang University (No. 2021-0696). The research involved no more than minimal risk to the participants. This study was a retrospective data analysis of previously collected medical records. Individual consent for this retrospective analysis was waived by the Institutional Review Board (IRB). The operability evaluation included a panel of oncological assessments (including respiratory function tests, computed tomography scanning of the chest or magnetic resonance imaging chest, brain magnetic resonance imaging), and standard pulmonary and cardiac function tests. Based on the results of assessments, the surgical treatment regimen was decided by senior consultant surgeon.
Clinical and demographic data (including age, sex, smoking history, body mass index, tumor diameter, location and pathologic style) were recorded. The operative time, estimated volume of blood loss, blood transfusion during the operation, conversion to the traditional thoracotomy, length of hospital stay, chest tube removal, complications, volume of postoperative drainage, mortality within 30 days were collected. Our research standard excluded thymoma patients with myasthenia gravis. The first TP-VATS thymectomy was performed in our group in 2013. The UP-VATS thymectomy technique was employed in 2015. The first 20 cases in each group were excluded to account for the learning curve effect.
Surgical technique
General anesthesia and double-lumen endotracheal intubation were routinely used. All patients were in the horizontal position with the surgical side elevated upward. The surgeon and assistant stood on the surgical sides of the patient.
For the UP-VATS thymectomy, a 4-cm incision was made between the midaxillary and anterior axillary line in the fourth intercostal space (in the fifth intercostal space for women). For the TP-VATS thymectomy, a 1cm incision was made at the anterior axillary line in the third intercostal space as the assistant utility port. Another 1 cm incision was made at the midaxillary line in the fifth intercostal space as the observation port. A 3 cm mini-thoracotomy was made at the fifth intercostal space between the midclavicular line and anterior axillary line in the fifth intercostal space as the major utility port. In the TP-VATS, the major utility port was sealed with a plastic protective jacket. In the UP-VATS, a plastic protective jacket was used for the only port with no sealing during the procedure. CO2 insufflation with a pressure of 8 cmH2O was used in the TP-VATS procedures. After confirmation of the location of the target tumor, the dissections of the anterior mediastinum were separated and sectioned progressively.
After the operation, the main chest tube (22-Fr) was inserted and connected to an underwater sealed bottle for postoperative drainage. The criteria for tube removal were no air leakage and a drainage volume of less than 200 mL per day. Meanwhile, the color of the drainage fluid must be within tolerance interval. Complications were all treated with appropriate medication when necessary. Patients were discharged only if their well-being met the criteria assessed by senior doctors.
Statistical analysis
Clinical information of all selected patients was gathered by the authors from the database of The Second Affiliated Hospital of Zhejiang University. A one-to-one propensity score matching analysis was used for the comparison of the UP-VATS and TP-VATS thymectomy. A multinomial logistic regression model was applied based on age, sex, smoking history, body mass index, tumor diameter and location, and pathologic style. A 1:1 match was achieved using the nearest neighbor-matching algorithm with a caliper definition of 0.02. In order to ensure that the final outcome could produce stable results, matching was repeated several times.
Variables were presented as proportions, means, or medians where appropriate. Data were compared using Student’s t-test, χ2 test, one-way ANOVA or the Mann-Whitney U test where appropriate. All statistical analyses were performed with SPSS version 23.0 (International Business Machines Corporation, Armonk, NY, USA). Significant differences were defined with a P value below 0.05.
Results
Clinical baseline
The surgical location for UP-VATS and TP-VATS thymectomy groups is shown in Figure 1. From January 2013 to December 2022, 363 patients (without myasthenia gravis) with thymoma were enrolled for analysis in this study (Figure 2). The first 20 cases in the UP-VATS and TP-VATS thymectomy groups were excluded to account for the learning curve effect. Among the 323 patients, 115 underwent the UP-VATS thymectomy, and 208 accepted the TP-VATS thymectomy. After propensity score matching analysis, a total of 230 closely matched patients were picked up in the end. The baseline demographic parameters and clinical characteristics of the study cohort before and after matching are listed in Table 1. As shown in Table 1, the demographic and clinical characteristics of the two groups were well balanced. There was no significant difference in terms of demographic parameters and clinical characteristics in patients between the two groups.
Table 1
| Variables | All patients | Propensity-matched patients | |||||
|---|---|---|---|---|---|---|---|
| Single-port (n=115) | Three-port (n=208) | P value | Single-port (n=115) | Three-port (n=115) | P value | ||
| Age (years) | 54.63±0.94 | 55.5±0.72 | 0.68 | 54.63±0.94 | 55.39±0.99 | 0.81 | |
| Sex | 0.73 | 0.51 | |||||
| Male | 53 (46.1) | 100 (48.1) | 53 (46.1) | 58 (50.4) | |||
| Female | 62 (53.9) | 108 (51.9) | 62 (53.9) | 57 (49.6) | |||
| Smoking history | 0.62 | 0.89 | |||||
| Yes | 41 (35.7) | 80 (38.5) | 41 (35.7) | 40 (34.8) | |||
| No | 74 (64.3) | 128 (61.5) | 74 (64.3) | 75 (65.2) | |||
| BMI (kg/m2) | 23.70±0.24 | 23.62±0.18 | 0.83 | 23.7±0.24 | 23.3±0.25 | 0.60 | |
| Pathologic stage | 0.60 | 0.09 | |||||
| ≤ B1 | 54 (47.0) | 104 (50.0) | 54(47.0) | 67 (58.3) | |||
| > B1 | 61 (53.0) | 104 (50.0) | 61 (53.0) | 48 (41.7) | |||
| Tumor size (cm) | 4.20±0.17 | 4.27±0.12 | 0.97 | 4.20±0.17 | 4.16±0.15 | 0.54 | |
| Location | 0.74 | 0.69 | |||||
| Left | 52 (45.2) | 98 (47.1) | 52 (45.2) | 49 (42.6) | |||
| Right | 63 (54.8) | 110 (52.9) | 63 (54.8) | 66 (57.4) | |||
Data are presented as n (%) or mean ± standard deviation. BMI, body mass index.
Perioperative outcomes between the two groups
The perioperative comparisons are presented in Table 2. During the procedure, intraoperative frozen sections were routinely obtained. TP-VATS procedure took shorter operative time (96.7±2.1 vs. 117.2±5.3 min, P<0.001), resulting in less volume of drainage (76.1±1.3 vs. 86.2±1.7 mL, P=0.07) than the UP-VATS procedure.
Table 2
| Variables | Single-port (n=115) | Three-port (n=115) | P value |
|---|---|---|---|
| Operative time (min) | 117.2±5.3 | 96.7±2.1 | <0.001 |
| Blood loss (mL) | 54.9±7.1 | 57.3±3.7 | 0.09 |
| Conversion | 7 (6.1) | 5 (4.3) | 0.55 |
| Chest tube removal (days) | 1.1±0.03 | 1.2±0.03 | 0.054 |
| Blood transfusion | 3 (2.6) | 2 (1.7) | 0.60 |
| postoperative drainage (mL) | 86.2±1.7 | 76.1±1.3 | 0.08 |
| Length of stay (days) | 6.0±0.3 | 6.5±0.3 | 0.63 |
| Major complications | |||
| Atelectasis | 2 (1.7) | 3 (2.6) | 0.65 |
| Poor wound healing | 3 (2.6) | 4 (3.5) | 0.70 |
| Pneumonia | 12 (10.4) | 7 (6.1) | 0.23 |
| Total | 17 (14.8) | 14 (12.2) | 0.56 |
| Mortally | 0 | 0 | – |
Data are presented as n (%) or mean ± standard deviation.
Additionally, the main chest tube (22-Fr) could be removed on postoperative day (POD) 1 from patients in the UP-VATS group, which was similar to the TP-VATS group (1.1±0.03 vs. 1.2±0.03, P=0.054). The estimated volume of blood loss (54.9±7.1 vs. 57.3±3.7, P=0.09), the conversion (6.1% vs. 4.3%, P=0.55), length of hospital stay (6.0±0.3 vs. 6.5±0.3, P=0.63), the complication rate (14.8% vs. 12.2%, P=0.56) were comparable between the two groups with no significant differences.
Intraoperatively, there were 7 patients in the UP-VATS group who were converted to thoracotomy, while 5 patients in the TP-VATS group were converted to thoracotomy, due to uncontrolled bleeding (injury to the innominate vein) and severe adhesion in the thoracic cavity. There were 3 cases of blood transfusion in the UP-VATS group and 2 cases in the TP-VATS group during the operation for uncontrolled bleeding (2.6% vs. 1.7%, P=0.60) (injury to the innominate vein and the estimated volume of blood loss ≥300 mL). Major complications included chylothorax, atelectasis, empyema, pulmonary infection and pleural effusion. There was no intraoperative mortality and postoperative 30-day mortality between the two approaches.
Perioperative outcomes in the TP-VATS thymectomy group
Whether the perioperative outcomes in the TP-VATS thymectomy group varied with the preoperative variables (age, sex, tumor location, tumor size and pathological type), the TP-VATS thymectomy group was divided into subgroups for perioperative outcomes analysis. The comparison results are presented in Table 3. Subgroups procedure of tumor location (left), tumor size (≥3 cm) took longer operative time than subgroups procedure of tumor location (right), tumor size (≤3 cm) (101.3±2.3 vs. 79.2±2.5 min, P<0.001) (107.3±3.3 vs. 88.7±2.3 min, P=0.02) (Table 3). Subgroups procedure of tumor size (<3 cm) was associated with less volume of blood loss than subgroups procedure of tumor size (≥3 cm) (28.8±4.0 vs. 53.3±4.2 min, P=0.01).
Table 3
| Variable | n | Operative time (min) | Blood loss (mL) | Length of stay (day) |
|---|---|---|---|---|
| Age (years) | ||||
| <60 | 76 | 94.9±2.6 | 51.6±4.8 | 8.2±0.3 |
| ≥60 | 39 | 100.0±3.6 | 41.5±4.5 | 9.0±0.5 |
| P value | 0.84 | 0.16 | 0.11 | |
| Sex | ||||
| Male | 58 | 96.0±2.9 | 45.2±4.2 | 8.7±0.4 |
| Female | 57 | 97.3±3.0 | 51.2±5.7 | 8.2±0.4 |
| P value | 0.85 | 0.86 | 0.12 | |
| Tumor size (cm) | ||||
| ≥3 | 24 | 101.3±2.3 | 53.3±4.2 | 8.8±0.3 |
| <3 | 91 | 79.2±2.5 | 28.8±4.0 | 7.2±0.4 |
| P value | <0.001 | 0.01 | 0.09 | |
| Location | ||||
| Left | 49 | 107.3±3.3 | 44.9±6.0 | 8.0±0.3 |
| Right | 66 | 88.7±2.3 | 50.6±4.3 | 8.8±0.4 |
| P value | 0.02 | 0.56 | 0.34 |
Discussion
Accounting for nearly 20% to 40% of all types of mediastinal tumors in adults, thymoma is the most common mediastinal tumor. Thymectomy is indicated in various diseases, including thymoma, thymic cysts, and thymus carcinoma, and thymectomy is also a therapeutic option. The surgical approach to thymectomy remains controversial, and a variety of different techniques have been introduced in recent decades, each with its advantages and disadvantages. Complete thymectomy by open sternotomy is the traditional standard treatment for both benign and malignant thymomas (8,9). Proponents of open approaches to thymectomy discuss excellent visualization of the thymus and its surrounding structures as well as the ease of resection and reconstruction of involved structures. Recently, there has been considerable interest in expanding minimally invasive approaches for the surgical treatment of thymic resection. On account of the variety of approaches and techniques used for thymectomy, the International Thymic Malignancy Interest Group defined MIT as “any approach as long as no sternotomy (including partial sternotomy) or thoracotomy with rib spreading is involved and in which a complete resection of the tumor is intended”. As a minimally invasive surgery, VATS is relatively easy to adopt. The use of VATS thymectomy in patients was described over two decades ago (10). Proponents of MIT endorse improved visualization of the thymus gland and surrounding structures over open thymectomy (OT), and shorter recovery following surgery. A number of studies on thymectomy have demonstrated favorable short-term advantages of MIT compared to the sternotomy. The potential benefits include a smaller incision away from the midline, less trauma to the chest wall, faster healing, earlier return to normal activities and work, decreased post-operative length of stay, decreased cytokines, complete remission and no difference in outcomes. Less trauma and faster healing times also permit earlier administration of adjuvant chemo-radiation treatment in advanced cases. An increasing number of studies have shown that minimally invasive thoracoscopic surgery has significant advantages in different patients and types of mediastinal tumors (11-15). There are some studies reporting the advantages in surgical outcomes of VATS for thymectomy. According to these reports, VATS thymectomy demonstrated a superior outcome in terms of hospital stay, intraoperative blood loss, and cosmetic satisfaction when compared with open access surgery (5,16).
This MIT has gained popularity among patients due to its favorable surgical treatment outcomes. In our institution, VATS was employed in different ways, mainly including the UP-VATS thymectomy and the TP-VATS thymectomy. Because the effectiveness of these two MIT is unknown, we utilized our institutional dataset to determine whether UP-VATS thymectomy is equivalent to TP-VATS thymectomy. In this retrospective study, the TP-VATS thymectomy had a potential advantage compared to the UP-VATS thymectomy. The operative time in the TP-VATS group was significantly lower than that in the UP-VATS group. This significant difference between the two groups could be caused by attribution of CO2 insufflation. CO2 insufflation through a complete portal approach opens up the confined anterior mediastinum space and allows for bilateral phrenic nerve visualization and bilateral thymic horn dissection. Postoperative drainage and chest tube removal were not significantly different. Additionally, there was no significant difference in mortality between the two groups.
The VATS thymectomy is superior to the open procedures in regard to post-operative pain. However, the pain difference between the UP-VATS group and TP-VATS was not analysed in our study in considering of subjective nature of the visual analog pain score (VAS) and distinction in the control for pain management after the operation among patients. In our study, there was no difference in morbidity between the two groups, and there was also no difference in the incidence of complications. The overall morbidities were 14.8% an 12.2% in the UP-VATS group and the TP-VATS group respectively. Additionally, there was no death case in both groups. No significant difference in mortality exists between the two groups.
In our study, postoperative length of hospital, postoperative drainage and duration of chest tube drainage were similar between the two groups. Our perioperative data showed that the difference was not statistically significant between the two groups regarding operative time and perioperative blood loss. In this study, there was no difference in blood transfusion during the operation and length of hospital stay between the two groups. The length of hospital stay was 6.5±0.3 days in the TP-VATS, compared to 6.0±0.3 days in the UP-VATS. Intraoperatively, there were 7 patients in the UP-VATS group who were converted to thoracotomy, while 5 patients in the TP-VATS group were converted to thoracotomy, due to uncontrolled bleeding (injury to the innominate vein) and severe adhesion in the thoracic cavity. There were 2 cases of blood transfusion during the operation in TP-VATS group for uncontrolled bleeding, with 3 cases in UP-VATS group (injury to the innominate vein and the estimated volume of blood loss ≥300 mL). No significant differences exist between two groups.
Tumor location and size is a major concern before considering VATS thymectomy. Girard and colleagues (17) stated that VATS was contraindicated for large tumors, whereas Youssef and colleagues (18) suggested that VATS thymectomy was more appropriate in tumors smaller than 3 cm in diameter, more advantageous in tumors located in the right side. In the subgroups analysis, our results indicated that the tumor size bigger than 3 cm in diameter, the tumor location in the left anterior mediastinum would significantly take more operation time, compared to the corresponding subgroups. Meanwhile, subgroups analysis results indicated that the tumor size bigger than 3 cm in diameter would significantly cause more blood loss during the procedure, compared to the corresponding subgroups.
There are several limitations to this study. First, the major limitation is the retrospective single center design with its observational nature. Second, the surgical procedure performed and the decision to convert to open surgery were at the discretion of the surgeon, which might have resulted in potential bias. Third, our group had a limited number of cases. More case series should be investigated to establish the validity of our procedural result.
Conclusions
In conclusion, this propensity score-matched study suggests that the UP-VATS thymectomy and the TP-VATS thymectomy are associated with similar perioperative period outcomes for thymoma. Additionally, TP-VATS thymectomy provides an alternative for the thymoma treatment, having certain advantages compared to the UP-VATS thymectomy.
Acknowledgments
We acknowledge all members of Department of Thoracic Surgery, The Second Affiliated Hospital, Zhejiang University, Hangzhou, China for their support.
Footnote
Reporting Checklist: The authors have completed the STROBE reporting checklist. Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1305/rc
Data Sharing Statement: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1305/dss
Peer Review File: Available at https://jtd.amegroups.com/article/view/10.21037/jtd-2025-1305/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-2025-1305/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. This study was approved by the Ethics Committee of The Second Affiliated Hospital of Zhejiang University (No. 2021-0696). The research involved no more than minimal risk to the participants. This study was a retrospective data analysis of previously collected medical records. Individual consent for this retrospective analysis was waived by the Institutional Review Board (IRB).
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/.
References
- Rascoe PA, Kucharczuk JC, Cooper JD. Surgery of the mediastinum: historical notes. Thorac Surg Clin 2009;19:1-5. [Crossref] [PubMed]
- Heilmann C, Stahl R, Schneider C, et al. Wound complications after median sternotomy: a single-centre study. Interact Cardiovasc Thorac Surg 2013;16:643-8. [Crossref] [PubMed]
- Burt BM, Yao X, Shrager J, et al. Determinants of Complete Resection of Thymoma by Minimally Invasive and Open Thymectomy: Analysis of an International Registry. J Thorac Oncol 2017;12:129-36. [Crossref] [PubMed]
- Jurado J, Javidfar J, Newmark A, et al. Minimally invasive thymectomy and open thymectomy: outcome analysis of 263 patients. Ann Thorac Surg 2012;94:974-81; discussion 981-2. [Crossref] [PubMed]
- Meyer DM, Herbert MA, Sobhani NC, et al. Comparative clinical outcomes of thymectomy for myasthenia gravis performed by extended transsternal and minimally invasive approaches. Ann Thorac Surg 2009;87:385-90; discussion 390-1. [Crossref] [PubMed]
- Bachmann K, Burkhardt D, Schreiter I, et al. Long-term outcome and quality of life after open and thoracoscopic thymectomy for myasthenia gravis: analysis of 131 patients. Surg Endosc 2008;22:2470-7. [Crossref] [PubMed]
- Whitson BA, Andrade RS, Mitiek MO, et al. Thoracoscopic thymectomy: technical pearls to a 21st century approach. J Thorac Dis 2013;5:129-34. [Crossref] [PubMed]
- Maniscalco P, Tamburini N, Quarantotto F, et al. Long-term outcome for early stage thymoma: comparison between thoracoscopic and open approaches. Thorac Cardiovasc Surg 2015;63:201-5. [Crossref] [PubMed]
- Blalock A, Mason MF, Morgan HJ, Riven SS. Myasthenia gravis and tumors of the thymic region: report of a case in which the tumor was removed. Ann Surg 1939;110:544-61. [Crossref] [PubMed]
- Sugarbaker DJ. Thoracoscopy in the management of anterior mediastinal masses. Ann Thorac Surg 1993;56:653-6. [Crossref] [PubMed]
- Jiao J, Yu J, Chen C, et al. Thoracoscopic approach for massive thymic hyperplasia in an infant: Case report and literature review. Front Pediatr 2023;11:1144384. [Crossref] [PubMed]
- Gu Z, Hao X, Liu Y, et al. Minimally Invasive Thymectomy Could Be Attempted for Locally Advanced Thymic Malignancies: A Real-World Study With Propensity Score-Matched Analysis. J Thorac Oncol 2023;18:640-9. [Crossref] [PubMed]
- Alvarez A, Moreno P. Minimally invasive thymectomy: the best option for early and locally advanced epithelial thymomas. Eur J Cardiothorac Surg 2022;62:ezac279. [Crossref] [PubMed]
- Raja SM, Guptill JT, McConnell A, et al. Perioperative Outcomes of Thymectomy in Myasthenia Gravis: A Thoracic Surgery Database Analysis. Ann Thorac Surg 2022;113:904-10. [Crossref] [PubMed]
- Jung Y, Hong JI, Han KN, et al. Thoracoscopic anterior mediastinal mass removal using an articulating laparoscopic instrument. Interact Cardiovasc Thorac Surg 2021;33:498. [Crossref] [PubMed]
- Zahid I, Sharif S, Routledge T, et al. Video-assisted thoracoscopic surgery or transsternal thymectomy in the treatment of myasthenia gravis? Interact Cardiovasc Thorac Surg 2011;12:40-6. [Crossref] [PubMed]
- Girard N, Mornex F, Van Houtte P, et al. Thymoma: a focus on current therapeutic management. J Thorac Oncol 2009;4:119-26. [Crossref] [PubMed]
- Youssef SJ, Louie BE, Farivar AS, et al. Comparison of open and minimally invasive thymectomies at a single institution. Am J Surg 2010;199:589-93. [Crossref] [PubMed]
