Approaches to thymectomy in the minimally invasive era: a narrative review
Review Article

Approaches to thymectomy in the minimally invasive era: a narrative review

Leela Raj1, David Sahai1, Cohen Chaulk1, Rahul Nayak1,2 ORCID logo

1Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada; 2Department of Thoracic Surgery, London Health Sciences Center, London, ON, Canada

Contributions: (I) Conception and design: All authors; (II) Administrative support: All authors; (III) Provision of study materials or patients: None; (IV) Collection and assembly of data: None; (V) Data analysis and interpretation: None; (VI) Manuscript writing: All authors; (VII) Final approval of manuscript: All authors.

Correspondence to: Rahul Nayak, MD, MSc, FRCSC. Department of Thoracic Surgery, London Health Sciences Center, Office E2-004, 800 Commissioners Road E, London, ON N6A 5W9, Canada; Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, Canada. Email: Rahul.nayak@lhsc.on.ca.

Background and Objective: Thymectomies have the potential to significantly improve quality of life, especially in patients with myasthenia gravis (MG) refractory to medical management and thymic malignancies. Initially performed as open surgeries requiring a thoracotomy, techniques for thymectomies have now evolved to include minimally invasive approaches such as transcervical, transthoracic, lateral intercostal, and subxiphoid techniques. The objective of this review is to summarize the evolution of surgical approaches to thymic resection.

Methods: We conducted a search of the current literature regarding minimally-invasive surgical (MIS) approaches to thymectomy using the PubMed/Medline and Google Scholar databases. Articles were screened and included if they met one or more of the following criteria: (I) described the history and/or progression of MIS thymectomy; (II) described an approach to MIS thymectomy; (III) described the surgical outcomes of one or more of the MIS approaches to thymectomy; (IV) provided data comparing the outcomes and/or feasibility of MIS thymectomy.

Key Content and Findings: Three approaches currently prevail in the realm of minimally invasive thymectomies: the transcervical, video-assisted thoracic surgery (VATS) transthoracic or lateral intercostal, and subxiphoid techniques. Results of our search revealed robust effectiveness of all three approaches with good patient outcomes and minimal post-operative complications. The transcervical approach is the oldest of the minimally invasive approaches to thymectomy and offers the shortest length of post-operative hospital stay as it does not require chest tube placement. The transthoracic approach is presently the most widely used both in MG and in thymic malignancies. This VATS technique has the potential to be performed robotically and recently has shown good outcomes using a single port. Finally, the subxiphoid approach is the newest technique. Like the transthoracic approach, it can be performed robotically and is most commonly approached through a single port. The subxiphoid approach has the advantage of avoiding the intercostal nerves which are inevitably damaged in the transthoracic approach, and this is reflected in the significantly better pain scores outcomes between both techniques.

Conclusions: Overall, our search of the literature on minimally invasive thymectomies demonstrated significant progress of these techniques over the past two centuries with potential for continued improvement and incorporation of robotic techniques.

Keywords: Thymectomy; minimally-invasive; single-port; subxiphoid; narrative review

Received: 27 June 2024; Accepted: 06 March 2025; Published online: 25 March 2025.

doi: 10.21037/vats-24-23

Introduction

Background

Thymectomy involves removal of the thymic gland and can be indicated in the treatment of medically refractory myasthenia gravis (MG), thymoma, and thymic carcinomas. The first surgical practices in thymectomy were established by Blalock and colleagues in 1939 for the removal of a thymoma in a patient with MG through a sternotomy (1). Following this, open approaches including the lateral thoracotomy approach and median sternotomy approach became preferred techniques for thymectomies. More recently, minimally-invasive surgical (MIS) methods have taken center stage in many fields of surgery demonstrating improved patient comfort and faster recovery (2,3). MIS approaches have also found their role in thymectomy, with the most popular techniques including transcervical, transthoracic, and subxiphoid procedures. As shown by the meta-analysis published in 2016 by Yang et al., thoracoscopic approaches to thymectomy resulted in significantly lower blood loss and need for blood transfusion, shorter duration of chest tube insertion, shorter hospitalization post-operatively and lower complication rates than open approaches (4). Similarly, in their meta-analysis comparing video-assisted thoracic surgery (VATS) to open thymectomy, Qi et al. found that VATS procedures were associated with significantly lower rates of blood loss and total complications (5).

Rationale and knowledge gap

To our knowledge, there is no narrative review which details the different MIS approaches to thymectomy while also synthesizing surgical outcomes from landmark trials. Familiarity with MIS approaches to thymectomy equips surgeons with the knowledge required for potential implementation of these procedures at their own institutions. Additionally, an understanding of how MIS techniques in thymectomy have evolved is crucial to the development of future minimally invasive approaches.

Objective

The objective of this narrative review is to identify and detail the various approaches to minimally invasive thymectomy while synthesizing their surgical outcomes. We present this article in accordance with the Narrative Review reporting checklist (available at https://vats.amegroups.com/article/view/10.21037/vats-24-23/rc).

Methods

Our search was conducted between May 5, 2024 and June 9, 2024, using the PubMed/Medline and Google Scholar databases. A summary of the Medline search strategy is included in Table 1. The timeframe of the search was between 1939 and May 5, 2024. No restrictions were placed on the article type. Articles were screened and included if they met one or more of the following criteria: (I) described the history and/or progression of MIS thymectomy; (II) described an approach to MIS thymectomy; (III) described the short or long-term outcomes of one or more of the MIS approaches to thymectomy; (IV) provided data comparing the outcomes and/or feasibility of MIS thymectomy. An in-depth breakdown of our Medline search strategy is shown in Table 1. Details of our search strategy are summarized in Table 2.

Table 1

Medline search strategy

(“Thymectomy” AND “Minimally-Invasive” AND “History”)
(“Thymectomy” AND “Minimally-Invasive”) AND (“Approach*” OR “technique*”)
(“Thymectomy” AND “Transcervical”)
(“Thymectomy” AND (“Lateral Intercostal” OR “Transthoracic”))
(“Thymectomy” AND “Subxiphoid”)
(“Thymectomy” AND “VATS” OR “Video-Assisted Thoracic Surgery”)
(“Thymectomy” AND “Robotic”)

VATS, video-assisted thoracic surgery.

Table 2

The search strategy summary

Items Specification
Date of search May 5th to June 9th 2024
Databases and other sources searched PubMed/Medline, Google Scholar
Search terms used “thymectomy”, “minimally-invasive”, “approach”, “technique”, “transcervical”, “lateral intercostal”, “transthoracic”, “subxiphoid”, “VATS”, “video-assisted thoracic surgery”, “robotic”
Timeframe 1939 to May 5th 2024
Inclusion criteria No restrictions were placed on the article type. Articles were included if they met one or more of the following criteria: (I) described the history and/or progression of minimally-invasive thymectomy; (II) described an approach to minimally-invasive thymectomy; (III) described the short or long-term outcomes of one or more of the minimally-invasive approaches to thymectomy; (IV) provided data comparing the outcomes and/or feasibility of minimally-invasive thymectomy
Selection process Selection was conducted independently by L.R.
Additional considerations Occasionally, certain articles referenced in the papers yielded by the search were included

VATS, video-assisted thoracic surgery.

Discussion

Transcervical approach to thymectomy

Initially described toward the end of 20th century, the transcervical approach to thymectomy was the first of the MIS techniques for removal of the gland (6). At its conception, this technique was revolutionary as it offered an alternative to the invasive sternotomy. This approach was later modified to involve the use of a sternum-lifting, self-retaining retractor, significantly improving mediastinal exposure and allowing more complete removal of thymic tissue and extrathymic fat (7). This modified approach was named “extended” and is the method currently used in cases of transcervical thymectomies. The extended transcervical thymectomy utilizes a single 4–8 cm incision slightly above the sternal notch through which all instruments are inserted and the thymus gland is removed (7).

The transcervical approach offers several advantages over other approaches to minimally invasive thymectomy. Most notably, because there is generally no need for entering the pleural cavity, there is limited need for chest tube drainage thus limiting the necessity for prolonged hospital admissions post-operatively as shown in Calhoun et al.’s cohort of 100 MG patients undergoing transcervical thymectomies (8). Additionally, they showed a mean postoperative length of stay was 1.22 days (median 1.05 days; range, 0.6–4.1 days) with 85% of patients discharged on the first postoperative day. Although no studies to our knowledge have formally quantified pain score outcomes in patients undergoing transcervical thymectomies, this approach is believed to result in lower post-operative pain than transthoracic approaches as the intercostal nerves are not involved (9,10).

Important drawbacks to this approach include its contraindications in obesity and conditions limiting cervical spine motion as well as in patients having undergone previous mediastinal surgery (9,10). Additionally, due to the small size of the incision, there is a limitation to the visual field during the procedure and to the extent of tissue which can be excised (10). Moreover, while attempts have been made at performing transcervical thymectomies with a VATS approach, as reported by Zieliński et al., this is challenging due to the limited space and adds little benefit to the field of view (10).

Outcomes of the transcervical thymectomy are generally favorable. In their respective large, prospectively examined cohorts of transcervical thymectomy patients, Shrager et al. and Calhoun et al. reported complication rates of 6.7–7.3% and 8% respectively (8,9). None of these resulted in mortality and only one unilateral recurrent laryngeal nerve injury was classified as a major complication (8,9).

Transthoracic approach to thymectomy

The VATS transthoracic or lateral intercostal approach is currently the most widely used technique in MIS thymectomy. It has demonstrated good outcomes in terms of remission from both MG and thymoma (5,11). In comparison to the transcervical approach, the VATS approach offers a more extensive field of view (12). Additionally, the aesthetic outcomes from the incision when using this is believed to be generally more favorable for compared to the transcervical neck incision.

This technique most commonly involves the use of three ports through which the trocars are placed. Three-port transthoracic thymectomy can be approached through a bilateral or unilateral approach and in the latter case through the right or left chest (13). The optimal approach to this operation has long been debated and no clear consensus has been reached to date. Supporters of the left-sided approach site endorse a safer and easier achievement of complete dissection of the thymus gland due to location of the mediastinal fat on the left side of the anterior mediastinum (13). Conversely, supporters of the right-sided approach claim to increased space and easier identification of the brachiocephalic veins (13). To our knowledge, no studies have attempted head-to-head comparison of the three-port transthoracic approaches, and this is therefore largely guided by surgeon preference and experience.

As mentioned previously, one of the main drawbacks of the VATS approach compared to the transcervical thymectomy rests in the need for post-operative chest tube placement due to inherent violation of the pleura. This currently renders same-day discharge more challenging as compared to the transcervical approach. Despite this, outcomes in this regard appear to be improving with time. Indeed, in their 2015 systematic review of VATS vs. open thymectomy for thymoma, Xie et al. reported a mean hospital stay of 7.0 days for VATS patients (vs. 9.8 days for open) while a recent study of 594 thymectomies by Holleran et al. [2022] showed no statistically significant difference between post-operative length of stay in patients having undergone a transcervical vs. VATS thymectomy (14,15). Additionally, Holleran et al. [2022] showed that there was no difference in the 30-day complication rates between VATS and transcervical thymectomy patients (15). To our knowledge, no studies to date have directly compared pain scores directly between both approaches and this area therefore warrants further exploration.

Robotic transthoracic approach

The transthoracic approach also offers the potential to be performed robotically allowing the surgeon to overcome limitations of a VATS approach including 2-dimensional vision and limited depth perception. The robotic approach has been shown to be non-inferior to a VATS thymectomy in terms of post-operative outcomes, safety and effectiveness in a large systematic review by O’sullivan et al. in 2019 (16). Main limitations to this approach currently rest in equipment cost and availability; however, one can expect a growing number of robotic thymectomies and a concurrent rise in data with the advent of robotic surgery (17).

Uniportal transthoracic approach

More recently, there has been a rise in the number of reports of uniportal VATS thymectomy. While the size of published cohorts remains small, they suggest similar results to three-port VATS (18-20). The studies yielded by our search which involved the uniportal approach were successful in completing the totality of cases through an exclusively uniportal approach (18-20). Overall, post-operative complications in these studies were rare, with one case of hoarse voice and no reported mortalities (18). Blood loss with a uniportal approach appears generally lower than that observed in the three-port approach. Refai et al. [2020] and Wu et al. [2016] reported mean intraoperative blood loss volumes of 41 and 34.1±45.7 mL respectively in their uniportal VATS thymectomy cohorts while Hajjar et al. [2020], Wang et al. [2024], and Xie et al. [2015] describe losses of 118.8±68.7, 28.14±20.69, and 131.8 mL in their respective three-port VATS groups (14,19-22).

Overall, preliminary results for uniportal VATS thymectomies demonstrate few differences in terms of outcomes and patient safety when compared to the three-port approach and have demonstrated feasibility. Currently, this approach appears most suitable for removal of <4 cm of tissue and well-encapsulated tumours (23). However, it may have the potential to be expanded to more extensive lesions in the future.

Subxiphoid approach to thymectomy

The subxiphoid VATS approach is the most recently established technique of the MIS thymectomies. Classically, this approach is performed with a single port inserted through an incision about 1 cm below the level of the xiphoid process through which the camera and surgical instruments are inserted. Nonetheless, more extensive resections sometimes require the addition of one or two intercostal ports in an approach known as subxiphoid-subcostal thymectomy (24). To our knowledge, no reports of head-to-head comparison of the various subxiphoid approaches currently exist; however, several studies have focused on direct comparison of the subxiphoid and lateral intercostal approaches to minimally invasive thymectomy. Results of these studies showed no statistically significant differences in intraoperative blood loss, post-operative length of hospital stay, or complications between the subxiphoid and lateral intercostal approaches to thymectomy (25-28). Interestingly, despite the fact that all four of these studies included one or more intercostal incisions in their subxiphoid approach, all reported statistically significantly lower post-operative pain scores with the subxiphoid approach as compared to the lateral intercostal approach (25-28). Furthermore, in their analysis of 98 patients who underwent a thymectomy through the lateral intercostal or subxiphoid approach, Zhang et al. [2019] found greater cosmetic satisfaction in the subxiphoid group at 1-month post-operatively (25).

More recently, reports of robotic thymectomies using the subxiphoid approach have also been published. As in the case of the lateral intercostal approach, the robotic subxiphoid technique allows for improved exposure of the surgical field (24). While our search did not yield any studies providing direct comparison in outcomes between the robotic subxiphoid approach and other minimally-invasive approaches to thymectomy, Kang et al.’s 2020 study which included 107 thymectomy patients having undergone the procedure through a subxiphoid robotic approach demonstrated minimal complications (1.8%), a shorter length of stay than that typically reported for lateral intercostal approaches (2.2±1.4 days), and comparable intraoperative blood loss (73.5±104.5 days) (29).

As the subxiphoid approach to minimally invasive thymectomy gains interest and popularity, variants if the original technique are also being tested. Of particular interest is a recent series of 10 cases reported by Liu et al. [2021] in which uniportal subxiphoid thymectomies were successfully performed in non-intubated patients with outcomes comparable to a lateral intercostal approach (30). According to the authors, this approach has the potential to decrease the risk of myasthenic crises postoperatively (30). While this has yet to be validated in larger studies, such work is an example of the potential to further expand this method to ensure ongoing improvement in patient safety and outcomes.

Conclusions

Thymectomies have the potential to make tremendous impacts on the quality of life of patients with MG and extend life in those with thymic malignancies. Over the past several decades, the procedure has seen rapid evolution from invasive approaches, usually involving sternotomy, to a range of MIS methods and, most recently, the addition of robotic techniques. Each of these methods each confer unique benefits. All three of the currently used MIS techniques for thymectomy appear to have good profiles with regards to patient safety and effectiveness. While the most common technique currently remains lateral intercostal VATS, the subxiphoid approach is rapidly gaining popularity. As robotic techniques become increasingly prevalent, we foresee further evolution in the MIS thymectomy in the near future.

Acknowledgments

None.

Footnote

Reporting Checklist: The authors have completed the Narrative Review reporting checklist. Available at https://vats.amegroups.com/article/view/10.21037/vats-24-23/rc

Peer Review File: Available at https://vats.amegroups.com/article/view/10.21037/vats-24-23/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://vats.amegroups.com/article/view/10.21037/vats-24-23/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.

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

  1. Blalock A, Mason MF, Morgan HJ, et al. 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]
  2. Wang BY, Liu CC, Shih CS. Short-term results of thoracoscopic lobectomy and segmentectomy for lung cancer in koo foundation sun yat-sen cancer center. J Thorac Dis 2010;2:64-70. [PubMed]
  3. Landreneau RJ, Mack MJ, Hazelrigg SR, et al. Prevalence of chronic pain after pulmonary resection by thoracotomy or video-assisted thoracic surgery. J Thorac Cardiovasc Surg 1994;107:1079-85; discussion 1085-6. [Crossref] [PubMed]
  4. Yang Y, Dong J, Huang Y. Thoracoscopic thymectomy versus open thymectomy for the treatment of thymoma: A meta-analysis. Eur J Surg Oncol 2016;42:1720-8. [PubMed]
  5. Qi K, Wang B, Wang B, et al. Video-assisted thoracoscopic surgery thymectomy versus open thymectomy in patients with myasthenia gravis: a meta-analysis. Acta Chir Belg 2016;116:282-8. [PubMed]
  6. Singh G, Sonett JR. The evolution of thymic surgery through the years in art and history. Mediastinum 2018;2:33.
  7. Cooper JD, Al-Jilaihawa AN, Pearson FG, et al. An improved technique to facilitate transcervical thymectomy for myasthenia gravis. Ann Thorac Surg 1988;45:242-7. [Crossref] [PubMed]
  8. Calhoun RF, Ritter JH, Guthrie TJ, et al. Results of transcervical thymectomy for myasthenia gravis in 100 consecutive patients. Ann Surg 1999;230:555-9; discussion 559-61. [Crossref] [PubMed]
  9. Shrager JB. Extended transcervical thymectomy: the ultimate minimally invasive approach. Ann Thorac Surg 2010;89:S2128-34. [Crossref] [PubMed]
  10. Zieliński M, Rybak M, Solarczyk-Bombik K, et al. Transcervical thymectomy. Mediastinum 2018;2:28. [Crossref]
  11. 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]
  12. Raza A, Woo E. Video-assisted thoracoscopic surgery versus sternotomy in thymectomy for thymoma and myasthenia gravis. Ann Cardiothorac Surg 2016;5:33-7. [PubMed]
  13. Elsayed HH, Gamal M, Raslan S, et al. Video-assisted thoracoscopic thymectomy for non-thymomatous myasthenia gravis: a right-sided or left-sided approach? Interact Cardiovasc Thorac Surg 2017;25:651-3. [Crossref] [PubMed]
  14. Xie A, Tjahjono R, Phan K, et al. Video-assisted thoracoscopic surgery versus open thymectomy for thymoma: a systematic review. Ann Cardiothorac Surg 2015;4:495-508. [PubMed]
  15. Holleran TJ, Napolitano MA, Crowder HR, et al. Clinical Outcomes and Technical Approach of Thymectomy in the Veterans Health Administration. Ann Thorac Surg 2022;113:1648-55. [Crossref] [PubMed]
  16. O'Sullivan KE, Kreaden US, Hebert AE, et al. A systematic review of robotic versus open and video assisted thoracoscopic surgery (VATS) approaches for thymectomy. Ann Cardiothorac Surg 2019;8:174-93. [Crossref] [PubMed]
  17. Ho C, Tsakonas E, Tran K, et al. Robot-Assisted Surgery Compared with Open Surgery and Laparoscopic Surgery: Clinical Effectiveness and Economic Analyses. Ottawa: Canadian Agency for Drugs and Technologies in Health; 2011.
  18. Scarci M, Pardolesi A, Solli P. Uniportal video-assisted thoracic surgery thymectomy. Ann Cardiothorac Surg 2015;4:567-70. [PubMed]
  19. Refai M, Gonzalez-Rivas D, Guiducci GM, et al. Uniportal video-assisted thoracoscopic thymectomy: the glove-port with carbon dioxide insufflation. Gland Surg 2020;9:879-85. [Crossref] [PubMed]
  20. Wu CY, Heish MJ, Wu CF. Single port VATS mediastinal tumor resection: Taiwan experience. Ann Cardiothorac Surg 2016;5:107-11. [Crossref] [PubMed]
  21. Hajjar WM, Almasry NW, Alarifi AS, et al. Comparison of the Outcomes Between Bilateral Thoracoscopic Maximal Thymectomy Versus Trans-Sternal Maximal Thymectomy for Non-Thyomomatous Myasthenia Gravis Patients: A Local University Hospital Experience. Cureus 2020;12:e12288. [Crossref] [PubMed]
  22. Wang S, Yang X, Jiang J, et al. Subxiphoid versus lateral intercostal thoracoscopic thymectomy for suspected thymoma: Results of a randomized controlled trial. J Thorac Cardiovasc Surg 2024;168:290-8. [Crossref] [PubMed]
  23. Ye B, Tantai JC, Ge XX, et al. Surgical techniques for early-stage thymoma: video-assisted thoracoscopic thymectomy versus transsternal thymectomy. J Thorac Cardiovasc Surg 2014;147:1599-603. [Crossref] [PubMed]
  24. Suda T. Subxiphoid thymectomy: single-port, dual-port, and robot-assisted. J Vis Surg 2017;3:75. [Crossref] [PubMed]
  25. Zhang L, Li M, Jiang F, et al. Subxiphoid versus lateral intercostal approaches thoracoscopic thymectomy for non-myasthenic early-stage thymoma: A propensity score -matched analysis. Int J Surg 2019;67:13-7. [Crossref] [PubMed]
  26. Li Y, Huang Z, Han W, et al. Subxiphoid and subcostal arch versus unilateral video-assisted thoracic surgery approaches to thymectomy for myasthenia gravis. Surg Today 2023;53:12-21. [Crossref] [PubMed]
  27. Jiang L, Chen H, Hou Z, et al. Subxiphoid Versus Unilateral Video-assisted Thoracoscopic Surgery Thymectomy for Thymomas: A Propensity Score Matching Analysis. Ann Thorac Surg 2022;113:1656-62. [Crossref] [PubMed]
  28. Song N, Li Q, Aramini B, et al. Double sternal elevation subxiphoid versus uniportal thoracoscopic thymectomy associated with superior clearance for stage I-II thymic epithelial tumors: Subxiphoid thymectomy compared with VATS. Surgery 2022;172:371-8. [PubMed]
  29. Kang CH, Na KJ, Song JW, et al. The robotic thymectomy via the subxiphoid approach: technique and early outcomes. Eur J Cardiothorac Surg 2020;58:i39-43. [PubMed]
  30. Liu Z, Zhang L, Tang W, et al. Non-intubated uniportal subxiphoid thoracoscopic extended thymectomy for thymoma associated with myasthenia gravis. World J Surg Oncol 2021;19:342. [PubMed]
doi: 10.21037/vats-24-23
Cite this article as: Raj L, Sahai D, Chaulk C, Nayak R. Approaches to thymectomy in the minimally invasive era: a narrative review. Video-assist Thorac Surg 2025;10:7.

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