Management of large anterior mediastinal mass by video-assisted thoracoscopic surgery

Abstract

Background

There are controversies regarding managing anterior mediastinal mass greater than 5 cm by video-assisted thoracoscopic surgery (VATS). This study aims to present a single-center experience in using VATS to resect large anterior mediastinal masses using either unilateral or bilateral approach.

Methods

This is a retrospective case series, including consecutive patients referred for surgical management of anterior mediastinal mass, provided the mass was equal to or larger than five centimeters. Only phase I (unilateral VATS) was performed for those with a single approach, while phase one and phase II (bilateral VATS) were performed for those with dual approach.

Results

The study included eight cases; 4 (50%) were male, and 4 (50%) were female. All of the cases had features of myasthenia gravis. The average diameter of the mass on the computed tomography scan was 7 cm, ranging from 5 to 12 cm. Dual VATS was utilized in three (37.5%) cases, which showed both left and right extension. The average blood loss was 180 ml, ranging from 130 to 250 ml. All of the cases were thymoma. Complete resection was achieved in all cases with R0. Neither mortality nor recurrence was reported in the follow-up period (14 months average ranging from 6 to 36 months).

Conclusions

VATS is a safe and effective approach for large anterior mediastinal masses, with satisfactory operative outcomes, minimal morbidity, and promising oncological results. Dual VATS may be particularly useful for lesions with significant bilateral extension.

Background

Managing large anterior mediastinal masses (AMMs) remains controversial, particularly concerning the feasibility and safety of minimally invasive approach such as video-assisted thoracoscopic surgery (VATS). Traditionally, large AMMs, especially those exceeding 5 cm in diameter, have been approached via sternotomy or thoracotomy to ensure adequate exposure and safe resection, given the proximity of these masses to critical mediastinal structures, including the heart, great vessels, trachea, and phrenic nerves. However, recent advancements in thoracoscopic techniques and instrumentation have expanded the indications for VATS, even for large mediastinal lesions, challenging the conventional preference for open surgery [1, 2].

Several concerns have been raised regarding the application of VATS for large AMMs. One of the primary concerns is the risk of inadequate visualization and limited maneuverability within the confined thoracic cavity, which can increase the likelihood of incomplete resection or vascular injury. Additionally, a significant consideration is the potential for hemodynamic instability due to the mass effect on major vessels and airways during positioning and one-lung ventilation. Some studies have suggested that tumors greater than 5 cm pose significant challenges in retrieval and may require conversion to open surgery. However, proponents of VATS argue that improved surgical expertise, dual-port or multiport approach, and carbon dioxide insufflation can facilitate better exposure and safe resection in selected cases [3, 4].

This study aims to present a single-center experience in using VATS to resect large anterior mediastinal masses using either unilateral or bilateral approach. All references included in this study were evaluated for eligibility [5].

Methods

Study design and settings

This is a retrospective case series including consecutive patients referred for surgical management of anterior mediastinal mass, provided the mass was equal to or larger than five centimeters. The duration of the study included 3 years (September 2021 to September 2024). The present study received approval from Ethics Committee of College of Medicine-Sulaimani University- (2025/no. 105).

Exclusion criteria

Patients with the cystic mediastinal lesion, those with invasion to the surrounding vital structures precluding complete resection, and patients in whom VATS was not appropriate, such as those with intolerance to single lung ventilation or those with severe comorbidities.

Techniques

Only phase I was performed for those with unilateral extension, while phase I and phase II were performed for those with bilateral extension (dual approach). The decision to proceed with a dual approach was primarily guided by preoperative CT imaging (Fig. 1). Specifically, left-sided lesions with extension toward the superior vena cava, or right-sided lesions with extension toward the pulmonary artery, were considered indications for dual VATS.

Fig. 1.

Computed tomography scan (axial section) of the chest showing a lobulated anterior mediastinal mass (red arrows) extending from the left side to the right side

Phase I

All patients underwent peripheral venous cannulation, and a double-lumen endotracheal tube was inserted and confirmed via flexible bronchoscopy. The patient was placed in a supine position. The surgeon and assistant inserted the ports from the patient’s left side while the scrub nurse provided instruments from the right. During single-lung ventilation of the right lung, a 10 mm trocar for the camera was positioned in the 4th intercostal space along the left mid-axillary line. Once the placement was verified, CO₂ insufflation was initiated, maintaining pressures between 8 and 12 mmHg. Using direct visualization through the camera, two additional ports were introduced: a 5 mm port at the 3rd intercostal space along the anterior axillary line and another 5 mm port at the 6th intercostal space at the mid-clavicular line. Dissection began by carefully separating the thymic tissue along the left phrenic nerve and pericardium, progressing until the innominate vein was exposed. The cervical portions of both thymic horns were meticulously dissected and excised from the neck, with all venous branches secured using 5 mm hemoclips. The specimen was removed if the resection could be completed without further steps. A chest tube was placed, and the remaining port sites were closed.

Phase II

This phase was performed without the use of CO₂ insufflation. The surgical team repositioned, with the surgeon and assistants moving to the patient’s right side and the scrub nurse relocating to the left. Ports were inserted on the right side, mirroring their locations from the left. Single-lung ventilation was shifted to the left lung, allowing the right lung to collapse. Dissection commenced adjacent to the right phrenic nerve, with mediastinal attachments of the thymus and the mass carefully divided under direct visualization. A bipolar sealing device was used to ensure precision, especially during the separation of the pleura near the right phrenic nerve. The specimen was removed via the camera port and enlarged as needed.

A single chest tube was then placed through the camera port in all patients. In cases involving dual approach, the drain was positioned on the left side with multiple side holes to ensure adequate drainage of both hemithoraces. The remaining port sites were securely closed. Chest X-ray was used to confirm full lung expansion, and the drain was removed once drainage was minimal, typically within 2–3 days postoperatively.

Phase I (single approach) was used for cases where the mass could be resected from the left side, and both phases (dual approach) were used when the mass could not be separated from the left side.

Follow-up protocol

Patients were initially seen 12 days after discharge for general assessment and suture removal, followed by a visit at 6 weeks. Thereafter, follow-up assessments are scheduled every 6 months for the first 2 years and annually thereafter.

Data collection and analysis

Sociodemographic and clinical data were collected from the patient’s medical records and later transferred to an Excel sheet. SPSS (Statistical Package for the Social Sciences) was used to analyze the data. Descriptive statistics like mean, range, frequency, and percentage were used to present the data.

Results

The study included eight cases; 4 (50%) were male, and 4 (50%) were female. All of the cases had features of myasthenia gravis. The average diameter of the mass on computed tomography was 7 cm, ranging from 5 to 12 cm. Dual VATS was utilized in three (37.5%) cases, which showed both left and right extension. The operative times ranged from 130 min to 210 min, with an average of 143 min. The average blood loss was 180 ml, ranging from 130 to 250 ml. All of the cases were thymoma. The average duration of hospital stay was 3 days, ranging from 2 to 7 days. Complete resection (R0) was confirmed by histopathological examination in all cases. Neither mortality nor recurrence was reported in the follow-up period (14 months average, ranging from 6 to 36 months).

Discussion

Video-assisted thoracoscopic surgery can be a feasible and practical approach for managing large AMMs exceeding 5 cm in diameter. Despite historical concerns about VATS’s limitations in terms of exposure, maneuverability, and oncological adequacy, this study’s findings also support its potential benefits in carefully selected cases [3, 6].

A key consideration when applying VATS to large AMMs is the ability to achieve adequate visualization and complete resection while minimizing intraoperative complications. One of the main concerns surrounding minimally invasive techniques for large mediastinal masses is the risk of hemodynamic instability due to mass effect on the major vessels and airways, particularly during patient positioning and single-lung ventilation. In our study, carbon dioxide insufflation and a strategic port placement facilitated excellent visualization, allowing safe and efficient dissection. Additionally, the phased unilateral and bilateral approach provided flexibility in addressing masses with significant mediastinal extension, thereby ensuring R0 resection in all cases. Miyazaki et al. highlighted the successful application of a rarely utilized simultaneous bilateral VATS in the prone position for the resection of a middle mediastinal schwannoma. Given the tumor’s bilateral extension into both thoracic cavities and its proximity to critical structures such as the trachea and esophagus, a minimally invasive approach was chosen to achieve optimal exposure and complete resection. The prone position facilitated improved visualization of the posterior mediastinum and enhanced access to the tumor from both sides. Bilateral VATS allowed for precise dissection while minimizing trauma to adjacent structures [6].

A study by Matilla et al. showed a minimally invasive surgical approach for the resection of large anterior mediastinal tumors, utilizing a combined left-sided VATS and subxiphoid incision technique. This method was designed to facilitate radical resection and specimen retrieval without rib spreading, addressing the challenges associated with large tumors exceeding 4 cm in diameter. By incorporating a left-sided VATS approach, the surgeons achieved optimal visualization of the mediastinal structures, while the subxiphoid incision allowed for en-bloc tumor extraction with minimal postoperative discomfort. The technique demonstrated relatively short operative times (117–151 min) and rapid recovery. Notably, the approach preserved both phrenic nerves, ensuring functional integrity. The authors concluded that the combined VATS-subxiphoid technique offers a safe, effective alternative for large mediastinal tumors without radiological evidence of invasion, expanding the scope of minimally invasive thoracic surgery [7]. The average operative time of 143 min in this cohort falls within acceptable limits compared to both open thymectomy and other reports of VATS thymectomy for large lesions. Dual VATS, which was utilized in 37.5% of cases, did not appear to significantly increase operative times beyond what is expected for complex minimally invasive procedures. This highlights the advantage of a staged approach in ensuring complete resection, particularly for tumors extending bilaterally. Furthermore, the estimated intraoperative blood loss was relatively low (average 180 ml), reinforcing that VATS can offer a homeostatically controlled environment even for large lesions [6, 7].

In addition, the present study’s perioperative outcomes compare favorably with published minimally invasive thymectomy series. Ke et al. reported on 129 patients undergoing VATS thymectomy, showing a mean blood loss of 20–22 mL, a mean hospital stay of 4.1–4.4 days, and complication rates of 4.9–8.8% [3]. Although the current study reported a slightly higher mean blood loss, the average hospital stay was shorter (3 days), and neither mortality nor recurrence was observed. Similarly, Matilla et al. demonstrated minimal blood loss (< 150 mL), hospital stay of 3 days, and no morbidity or mortality in large mediastinal tumor resections [7]. Marshall et al. also reported that VATS for complex mediastinal resections reduced hospital stay compared with open surgery, in some cases permitting discharge within 1–2 days, alongside better pain control [8]. Hughes et al. documented a case of a 14.7 cm thymic cyst resected thoracoscopically with discharge by day 7, despite comorbidities, and Kakamad et al. described safe VATS management of a giant teratoma with discharge within 48 h [9, 10]. Moreover, evidence from a large systematic review of over 2,000 patients comparing minimally invasive with open thymectomy demonstrated mean estimated blood loss ranging from 20 to 200 mL in the minimally invasive group versus 86–466 mL in the open group, and a hospital length of stay of 1–10.6 days compared with 4–14.6 days in the open surgery group [11].

One of the primary concerns with minimally invasive resection of large AMMs is the potential need for conversion to an open approach. Notably, none of the cases in this study required conversion to sternotomy or thoracotomy, demonstrating that with proper preoperative planning and technique, VATS can be performed successfully, even for challenging mediastinal tumors. The avoidance of open surgery provides clear benefits, including reduced postoperative pain, shorter hospital stays, and faster recovery times. Indeed, the average hospital stay of 3 days in this cohort supports the minimally invasive nature of the procedure and is consistent with previous reports [2, 8, 9].

Oncological outcomes are a crucial consideration in evaluating the efficacy of VATS for large thymomas. In this study, complete resection (R0) was achieved in all cases, and there were no reported recurrences in the follow-up period (average 14 months, ranging from 6 to 36 months). These results suggest that VATS can provide oncological outcomes comparable to open surgery when applied in properly selected cases. However, longer-term follow-up with larger sample sizes is needed to assess the recurrence rates comprehensively.

This study has several limitations. The small sample size limits our conclusions’ generalizability, and the study’s retrospective nature introduces potential selection bias. Additionally, while this study demonstrates the feasibility of VATS for large AMMs, selecting appropriate cases based on tumor characteristics, patient comorbidities, and surgical expertise remains critical.

Conclusion

In conclusion, VATS is a safe and effective approach for large anterior mediastinal masses, with satisfactory operative outcomes, minimal morbidity, and promising oncological results. Dual VATS may be particularly useful for lesions with significant bilateral extension. With continued minimally invasive techniques and instrumentation advancements, VATS may increasingly replace open surgery for selected patients with large AMMs. Future studies with larger cohorts and extended follow-up periods will be essential in further validating these findings and establishing standardized guidelines for applying VATS in large mediastinal tumors.

Author contributions

Fahmi H.Kakamad: The surgeon who manage the cases, follow-up, and final approval of the manuscript and contributor to the conception of the study, as well as to the literature search for related studies. Kaiwan Talib Saeed, Shyar Mohammed Ibrahimn, and Shad Awat Ghafur: literature review, data collection, analysis, and interpretation, and the writing of the manuscript. Fahmi H.Kakamad and Kaiwan Talib Saeed: confirmed the authenticity of all the raw data. All authors have read and approved the final manuscript.

Funding

Smart Health Tower; Department of Scientific Research.

Data availability

The data that support the findings are available from the corresponding author upon request.

Declarations

Ethics approval and consent to participate

The present study received ethical approval from the Sulaimani University, Ethics Committee College of Medicine, Sulaymaniyah, Iraq (2025/no. 105).

Consent for publication

. Not applicable as the study is a retrospective one.

Competing interests

The authors declare no competing interests.