Does Surgical Removal of the Thymus Have Deleterious Consequences?

The role of immunosenescence, particularly the natural process of thymic involution during aging, is increasingly acknowledged as a factor contributing to the development of autoimmune diseases and cancer. Recently, a concern has been raised about deleterious consequences of the surgical removal of thymic tissue, including for patients who undergo thymectomy for myasthenia gravis (MG) or resection of a thymoma. This review adopts a multidisciplinary approach to scrutinize the evidence concerning the long-term risks of cancer and autoimmunity postthymectomy. We conclude that for patients with acetylcholine receptor antibody-positive MG and those diagnosed with thymoma, the removal of the thymus offers prominent benefits that well outweigh the potential risks. However, incidental removal of thymic tissue during other thoracic surgeries should be minimized whenever feasible.

Results Of Minimally Invasive Vats Thymectomy In Miastenia Gravis Patients Compared With More Invasive Approaches - 10-Year Experience In A Single Center.

INTRODUCTION: Myasthenia gravis (MG) is an autoimmune, neurologic disease that causes a wide range of symptoms. While the transsternal, transcervical and thoracotomy approaches are accepted as effective, there is still debate regarding the VATS approach. MATERIALS AND METHODS: We analyzed our center's surgical experience with thymectomy for myasthenia gravis, comparing the results of patients operated on using VATS and more invasive approaches, over a period of 10 years. A search of the department's surgical database for myasthenia gravis cases between January 2010 and January 2021, revealed a total of 40 cases. Twenty-four patients were included in the final analysis and were distributed into two groups: the VATS procedure group (group A) and the open procedure group (group B). The latter included sternotomy, thoracotomy, transcervical and hemiclamshell approaches. Only radical thymectomies were included. The established outcomes were clinical improvement defined as asymptomatic remission, reduction, or discontinuation of the medication necessary to achieve optimal symptom control. RESULTS: The median follow-up time was 27 months (ranging from 4 to 75 months). Videothoracoscopy radical thymectomy was performed on 12 patients. Complete remission with no medication was achieved in 1 case (8.3%), while 2 patients (16.7%) became asymptomatic with reduced medication. An improvement (reduced symptoms or decreased medication) was observed in 8 cases (66.6%). No change in clinical outcome was noted in 1 patient (8.3%). None of the patients reported worsening symptoms. Open thymectomy was performed on 12 patients. Complete remission with no medication was achieved in 1 case (8.3%), while 2 patients (16.7%) became asymptomatic with reduced medication. An improvement was noted in 6 cases (50%). No change in clinical outcome was observed in 3 patients (25%) whereas 2 of them (16.7%) experienced slightly better symptom control but with a significant increase in medication. One patient (8.3%) described the clinical results as without any significant change. None of the patients reported worsening symptoms. CONCLUSION: The videotoracoscopic approach in the treatment of myasthenia gravis is non-inferior compared to the open approach and effective in a long-term follow-up, offering all the additional benefits of less invasive surgery.

Our experience with robotic-assisted thymic surgery.

Thoracic surgery is increasingly influenced by the development of minimally invasive approaches which have also influenced surgery in the area of the anterior mediastinum. The previously standard approach to the thymus via partial sternotomy was gradually replaced by the videothoracoscopic approach in most cases. In recent years, robotically assisted surgery has been gaining ground worldwide in this area, as well. The aim of our paper is to provide a comprehensive overview of procedures in the field of the thymus, including their indications, and to share our first experience with robot-assisted thymus surgery. At the 3rd Department of Surgery, since the start of the robot-assisted thymus surgery program, 23 thymectomies have been performed using this approach, of which 17 were performed for thymoma, 3 for myasthenia gravis, and 3 for parathyroid adenoma localized in thymus tissue. From our experience and the available data, it follows that the length of hospitalization, the rate of complications and the resulting effect of robot-assisted procedures is comparable to VTS procedures; however, the robot-assisted surgery also allows for mini-invasive treatment even in significantly obese patients and in patients with advanced thymic tumors who would otherwise be indicated for open thymectomy.

Effect of bilateral low serratus anterior plane block on quality of recovery after trans-subxiphoid robotic thymectomy: Results of a randomized placebo-controlled trial.

Purpose: This study aimed to investigate the impact of ultrasound-guided, bilateral, low level (T8-T9) deep serratus anterior plane (DSAP) blocks on postoperative recovery quality and postoperative analgesia in patients undergoing trans-subxiphoid robotic thymectomy (TRT). Methods: 39 patients undergoing TRT were randomized to receive either low DSAP block under general anesthesia (Group S) or the sham block (Group C) on each side. The primary outcome was the QoR-40 score at postoperative day (POD) 1. Secondary outcomes included numeric rating scale (NRS) scores over time, postoperative 48 hours opioid consumption, QoR-40 scores at POD 2, 30, and 90. Results: The QoR-40 scores on POD1-2 were higher in Group S than in Group C [179.1 (4.9) vs 167.7 (2.8), P < 0.01; 187.7 (4.6) vs 178.1 (3), P < 0.01, respectively]. Pain scores were significantly lower in Group S, both during resting and motion at postoperative 6h, 12h, and 24h (P < 0.05 for each). The total amount of sufentanil consumed in the first 48 h was lower in Group S than in Group C [61.4 (4.9) vs 78.9 (4.6), P < 0.001]. Conclusion: The bilateral low DSAP blocks enhanced the QoR-40 for 2 days postoperatively, relieved postsurgical pain, and reduced opioid consumption during the early postoperative period in patients undergoing TRT.

Long-term follow-up of non-myasthenic patients with early-stage thymoma who underwent extended thymectomy or limited resection.

BACKGROUD: The standard resection for early-stage thymoma is total thymectomy and complete tumour excision with or without myasthenia gravis but the optimal surgery mode for patients with early-stage non-myasthenic thymoma is debatable. This study analysed the oncological outcomes for non-myasthenic patients with early-stage thymoma treated by thymectomy or limited resection in the long term. METHODS: Patients who had resections of thymic neoplasms at Taipei Veteran General Hospital, Taiwan between December 1997 and March 2013 were recruited, exclusive of those combined clinical evidence of myasthenia gravis were reviewed. A total of 113 patients were retrospectively reviewed with pathologic early stage (Masaoka stage I and II) thymoma who underwent limited resection or extended thymectomy to compare their long-term oncologic and surgical outcomes. RESULTS: The median observation time was 134.1 months [interquartile range (IQR) 90.7-176.1 months]. In our cohort, 52 patients underwent extended thymectomy and 61 patients underwent limited resection. Shorter duration of surgery (p < 0.001) and length of stay (p = 0.006) were demonstrated in limited resection group. Six patients experienced thymoma recurrence, two of which had combined myasthenia gravis development after recurrence. There was no significant difference (p = 0.851) in freedom-from-recurrence, with similar 10-year freedom-from-recurrence rates between the limited resection group (96.2 %) and the thymectomy group (93.2 %). Tumour-related survival was also not significantly different between groups (p = 0.726).result CONCLUSION: Patients with early-stage non-myasthenic thymoma who underwent limited resection without complete excision of the thymus achieved similar oncologic outcomes during the long-term follow-up and better peri-operative results compared to those who underwent thymectomy.

Is Minimally Invasive Resection of Large Thymoma Appropriate?

BACKGROUND: Current practice patterns suggest open rather than minimally invasive (MIS) approaches for thymomas >4 cm. We hypothesized there would be similar perioperative outcomes and overall survival between open and MIS approaches for large (>4 cm) thymoma resection. METHODS: The National Cancer Database was queried for patients who underwent thymectomy from 2010 to 2020. Surgical approach was characterized as either open or MIS. The primary outcome was overall survival and secondary outcomes were margin status, and length of stay (LOS). Differences between approach cohorts were compared after a 1:1 propensity match. RESULTS: Among 4121 thymectomies, 2474 (60%) were open and 1647 (40%) were MIS. Patients undergoing MIS were older, had fewer comorbidities, and had smaller tumors (median; 4.6 vs 6 cm, P < .001). In the unmatched cohort, MIS and open had similar 90-day mortality (1.1% vs 1.8%, P = .158) and rate of positive margin (25.1% vs 27.9%, P = .109). MIS thymectomy was associated with shorter LOS (2 (1-4) vs 4 (3-6) days, P < .001). Propensity matching reduced the bias between the groups. In this cohort, overall survival was similar between the groups by log-rank test (P = .462) and multivariate cox hazard analysis (HR .882, P = .472). Multivariable regression showed shorter LOS with MIS approach (Coef -1.139, P < .001), and similar odds of positive margin (OR 1.130, P = .150). DISCUSSION: MIS has equivalent oncologic benefit to open resection for large thymomas, but is associated with shorter LOS. When clinically appropriate, MIS thymectomy may be considered a safe alternative to open resection for large thymomas.

The rate of QMGS change predicts recurrence after thymectomy in myasthenia gravis.

OBJECTIVE: To investigate the relationship between short-term changes in quantitative myasthenia gravis score (QMGS) after thymectomy and postoperative recurrence in myasthenia gravis (MG) patients without thymoma. METHODS: A retrospective observational cohort study. The QMGS of 44 patients with non-thymomatous MG were evaluated before and 1 month after thymectomy, and the frequency and time of postoperative recurrence were recorded. The reduction rate of QMGS (rr-QMGS) was defined as (QMGS one week before thymectomy - QMGS one month after thymectomy)/ QMGS one week before thymectomy × 100 %, as an indicator of short-term symptom change after thymectomy. The receiver operating characteristic (ROC) curve was established to determine an appropriate cut-off value of rr-QMGS for distinguishing postoperative recurrence. Multivariate Cox regression analysis was applied to predict postoperative recurrence. RESULTS: Postoperative recurrence occurred in 21 patients (30 times in total) during follow-up. The mean annual recurrence rate was 3.98 times/year preoperatively and 0.30 times/year postoperatively. ROC analysis determined the cut-off value of rr-QMGS was 36.7 % (sensitivity 90.5 %, specificity 52.2 %). Multivariate Cox regression analysis showed that rr-QMGS＜36.7 % (hazard rate[HR]6.251, P = 0.014) is positive predictor of postoperative recurrence. Kaplan-Meier analysis showed that postoperative recurrence time was earlier in the low rr-QMGS group than in the high rr-QMGS group (12.62 vs. 36.60 months, p = 0.005). CONCLUSIONS: Low rr-QMGS is associated with early postoperative recurrence. Rr-QMGS can be used to predict postoperative recurrence of non-thymomatous MG.

Robotic thymectomy in thymic tumours: a multicentre, nation-wide study.

OBJECTIVES: Robotic thymectomy has been suggested and considered technically feasible for thymic tumours. However, because of small-sample series and the lack of data on long-term results, controversies still exist on surgical and oncological results with this approach. We performed a large national multicentre study sought to evaluate the early and long-term outcomes after robot-assisted thoracoscopic thymectomy in thymic epithelial tumours. METHODS: All patients with thymic epithelial tumours operated through a robotic thoracoscopic approach between 2002 and 2022 from 15 Italian centres were enrolled. Demographic characteristics, clinical, intraoperative, postoperative, pathological and follow-up data were retrospectively collected and reviewed. RESULTS: There were 669 patients (307 men and 362 women), 312 (46.6%) of whom had associated myasthenia gravis. Complete thymectomy was performed in 657 (98%) cases and in 57 (8.5%) patients resection of other structures was necessary, with a R0 resection in all but 9 patients (98.6%). Twenty-three patients (3.4%) needed open conversion, but no perioperative mortality occurred. Fifty-one patients (7.7%) had postoperative complications. The median diameter of tumour resected was 4 cm (interquartile range 3-5.5 cm), and Masaoka stage was stage I in 39.8% of patients, stage II in 56.1%, stage III in 3.5% and stage IV in 0.6%. Thymoma was observed in 90.2% of patients while thymic carcinoma occurred in 2.8% of cases. At the end of the follow-up, only 2 patients died for tumour-related causes. Five- and ten-year recurrence rates were 7.4% and 8.3%, respectively. CONCLUSIONS: Through the largest collection of robotic thymectomy for thymic epithelial tumours we demonstrated that robot-enhanced thoracoscopic thymectomy is a technically sound and safe procedure with a low complication rate and optimal oncological outcomes.

Clinicopathological predictors of postoperative long-term myasthenic status in resected thymoma with myasthenia gravis.

PURPOSE: Surgical patients with thymoma and myasthenia gravis (MG) must have their MG status and oncological outcomes critically monitored. We aimed to identify clinicopathological predictors of the postoperative MG status. METHODS: We conducted a retrospective review of 40 consecutive surgical patients with MG-related thymomas between 2002 and 2020. The quantitative myasthenia gravis score (QMGS) and Myasthenia Gravis Foundation of America post-intervention status (MGFA-PIS) were used to evaluate postoperative MG status. RESULTS: All patients underwent extended total thymectomy. The most common WHO type was type B2 (32%), while 65% of patients had type B1-B3 and 35% had type A-AB thymomas. Eleven patients (28%) achieved controlled MG status in MGFA-PIS 6 months after surgery. This controlled status was observed more frequently in type A-AB than in B1-B3 (57% vs. 12%, p = 0.007). In a multivariate analysis, WHO type (A-AB or B1-B3) was an independent predictor of worsening episodes of MG based on the QMGS (Type B1-B3, hazard ratio: 3.23, 95% confidence interval: 1.12-9.25). At the last follow-up, 23 patients (58%) achieved controlled MG status. The 5-year overall survival rate of all patients was 93.7%. CONCLUSION: The WHO type of thymoma is an informative predictor of postoperative MG status in patients with MG-related thymoma.

The Impact Of Thymectomy In Thymomatous And Nonthymomatous Myasthenia Gravis - The Experience Of A Tertiary Center.

INTRODUCTION: Thymectomy remains a mainstay of treatment in Thymomatous (T) and Nonthymomatous (nT) Myasthenia Gravis (MG), with improved clinical outcomes and reduced need for medical treatment, however, there is little research regarding long-term follow-up. We aim to assess the impact of surgery on the long-term outcome of patients with MG at our center. METHODS: Retrospective analyses of MG patients submitted to thymectomy between 2007 and 2017 at the thoracic surgery department of CHUC. Clinical assessment was performed according to the MG Foundation of America (MGFA) Clinical Classification (cMGFA). The follow-up was categorized according to the MGFA Post-intervention Status (MGFA-PIS) and cMGFA. Statistical analysis was performed with SPSS, to a significance level of 5%. RESULTS: Thirty-seven patients underwent extended thymectomy and 67.6% were female. Median age at diagnosis was 46.68±19.2 years. Most patients (83.8%) had anti-acetylcholine receptor antibodies and 81.1% had generalized forms of MG. Many patients (67.6%) had surgery less than 12 months after the clinical diagnosis. TMG was present in 19 (51.4%) patients. Compared to nTMG, these patients were older (54.06±17.9 vs 40.17±19.4 years) and most were men (52.9% vs 16.7%). We obtained a good outcome in most patients in the first (81.1%), second (86.1%), and fifth (84.8%) year of follow-up. There was a shift towards better prognosis categories in the good outcome group: 9.1% CSR, 3.0% PR, and 66,7% MM in the fifth year. Preoperative medical treatment did not influence the long-term follow-up outcome. A shorter time to surgery (< 12 months) correlated with better outcomes at year 5 (p=0.016). CONCLUSION: Thymectomy led to a sustained clinical improvement in our cohort, allowing for a reduced need for medication. A shorter time to surgery seems to have a positive influence on long-term prognosis. We expect that an extended follow-up would improve our results.

Thymoma negatively affects the neurological outcome of myasthenia gravis after thymectomy: a propensity score matching study.

BACKGROUND: Thymoma and myasthenia gravis (MG) interact with each other. This study aimed to evaluate the effects of thymoma on neurological outcome of MG patients after thymectomy using the propensity score matching (PSM) method. METHODS: Consecutive patients with MG who underwent thymectomy at Beijing Hospital between January 2012 and August 2021 were retrospectively enrolled. Clinical and follow-up data were collected. Statistical analysis was performed using SPSS 23.0 software. PSM was performed to eliminate selection bias. RESULTS: A total of 456 patients were included in this study. Thymoma was present in 138 (30.3%) patients. The median follow-up time was 72 (range, 12-135) months. At the last follow-up, a lower proportion of thymomatous MG patients achieved complete stable remission (CSR) compared with non-thymomatous MG patients (P = 0.011), and the effective rate [CSR + pharmatologic remission (PR) + minimal manifestations (MM)] of thymomatous MG patients was also lower (P = 0.037). Considering time to CSR, Kaplan-Meier analysis showed thymomatous MG patients had lower cumulative CSR rate than non-thymomatous MG patients (log-rank, P = 0.019). After PSM, 105 pairs of patients were matched successfully. For the matched patients, thymomatous MG patients had a lower CSR rate and a lower effective rate (P = 0.002, 0.039, respectively), and K-M analysis still showed thymomatous MG patients had lower cumulative CSR rate (log-rank, P = 0.048). Multivariate Cox analysis demonstrated that thymoma (HR: 0.592, 95% CI 0.389-0.900, P = 0.014), older age at the time of surgery (HR: 0.971, 95% CI 0.953-0.990, P = 0.003), and preoperative course of MG > 12 months (HR: 0.474, 95% CI 0.317-0.708, P = 0.000) were negative predictive factors for CSR. CONCLUSIONS: Thymoma had a negative effect on the neurological outcome of MG after thymectomy. MG patients with old age and a preoperative course of longer than one year had a lower probability of achieving CSR.

Robot-assisted surgery outperforms video-assisted thoracoscopic surgery for anterior mediastinal disease: a multi-institutional study.

Anterior mediastinal procedures are increasingly being performed using robot-assisted thoracic surgery (RATS) or video-assisted thoracoscopic surgery (VATS). While both approaches have shown superior outcomes compared to open surgery, their comparative benefits are not as distinct. The aim of this retrospective study was to bridge this knowledge gap using a multicenter dataset. Patients who underwent elective minimally invasive surgery for anterior mediastinal disease between 2015 and 2022 were deemed eligible. The study participants were grouped based on whether a robot was used or not, and perioperative outcomes were compared. To mitigate selection bias, inverse probability of treatment weighting (ITPW) was applied using the propensity score. The final analysis included 312 patients (RATS = 120; VATS = 192). Following the application of IPTW, RATS was found to be associated with a longer operating time (215.3 versus 139.31 min, P < 0.001), fewer days with a chest tube (1.96 versus 2.61 days, P = 0.047), and a shorter hospital stay (3.03 versus 3.91 days, P = 0.041) compared to VATS. Subgroup analyses indicated that the benefit of RATS in reducing the length of hospital stay was particularly pronounced in patients with tumors larger than 6 cm (mean difference [MD] = - 2.28 days, P = 0.033), those diagnosed with myasthenia gravis (MD = - 3.84 days, P = 0.002), and those who underwent a trans-subxiphoid surgical approach (MD = - 0.81 days, P = 0.04). Both VATS and RATS are safe and effective approaches for treating anterior mediastinal disease. However, RATS holds distinct advantages over VATS including shorter hospital stays and reduced chest tube drainage periods.

Propofol TCI or sevoflurane anesthesia without muscle relaxant for thoracoscopic thymectomy in myasthenia gravis patients: a prospective, observational study.

BACKGROUND: Myasthenia gravis (MG) patients interact unpredictably with anesthetic agents, including neuromuscular blocking agents. Here, we investigate the effectiveness of general anesthesia without muscle relaxants using either propofol via target-controlled infusion systems (TCI) or sevoflurane in MG patients undergoing thoracoscopic thymectomy. METHODS: This prospective, open-label, observational study was conducted in a university hospital. We included 90 myasthenic patients undergoing thoracoscopic thymectomy with general anesthesia. Patients received induction and maintenance anesthesia with propofol TCI (group P, n = 45) or induction with propofol 2-3 mg.kg-1 and maintenance anesthesia with sevoflurane (group S, n = 45). In both groups, the procedure was performed under the guidance of entropy with sufentanil but not a muscle relaxant. Intubation conditions, hemodynamic changes, respiratory function, neuromuscular transmission, arterial blood gas, and complications were evaluated. RESULTS: All patients achieved good intubation conditions. Hemodynamic instability was more frequent in group S than in group P, mostly in the induction stage, and was controllable. The reduction in the intraoperative train-of-four ratio from baseline at 30 min, 60 min, and 90 min in group S was 10.3%, 14.2%, and 14.3%, respectively, significantly higher than that in group P (6.8%, 7.2%, and 8.4%, respectively), which completely recovered at the end of the surgery. All patients were extubated in the operating room without complications. No other significant differences between the groups were observed. CONCLUSIONS: Anesthesia with propofol TCI or sevoflurane without muscle relaxants in MG patients offered safe and effective conditions for thoracoscopic thymectomy. Sevoflurane achieved higher levels of intraoperative muscular relaxation than propofol TCI. Postoperative neuromuscular function was not affected by these anesthetics.

Robot versus video-assisted thoracoscopic thymectomy for large thymic epithelial tumors: a propensity-matched analysis.

BACKGROUND: Both video-assisted thoracoscopic surgery (VATS) thymectomy and robot-assisted thoracoscopic surgery (RATS) thymectomy have been suggested as technically sound approaches for early-stage thymic epithelial tumors. However, the choice of VATS or RATS thymectomy for large and advanced thymic epithelial tumors remains controversial. In this study, the perioperative outcomes of VATS and RATS thymectomy were compared in patients with large thymic epithelial tumors (size ≥5.0 cm). METHODS: A total of 113 patients with large thymic epithelial tumors who underwent minimally invasive surgery were included. Sixty-three patients underwent RATS, and 50 patients underwent VATS. Patient characteristics and perioperative variables were compared. RESULTS: Compared with the VATS group, the RATS group experienced a shorter operation time (median: 110 min vs.130 min; P < 0.001) and less blood loss (30.00 ml vs. 100.00 ml, P < 0.001). No patients in the RATS group needed conversion to open surgery, but in the VATS series, five patients required conversion to open procedures (0% vs. 14.29%, P = 0.054). The rate of concomitant resection in the RATS group was similar to that in the VATS group (11.43% vs. 5.71%; P = 0.673). There was no significant difference between the two groups in the duration of chest tube (P = 0.587), postoperative complications (P = 1.000), and the duration of postoperative hospital stay (P = 0.141). CONCLUSION: For large thymic epithelial tumors, RATS thymectomy can be performed safely and effectively in a radical fashion. Due to the advanced optics and precise instrument control, concomitant resections can be easily achieved in larger thymic epithelial tumors using the robotic approach.

Serum metabolomics of treatment response in myasthenia gravis.

OBJECTIVE: High-dose prednisone use, lasting several months or longer, is the primary initial therapy for myasthenia gravis (MG). Upwards of a third of patients do not respond to treatment. Currently no biomarkers can predict clinical responsiveness to corticosteroid treatment. We conducted a discovery-based study to identify treatment responsive biomarkers in MG using sera obtained at study entry to the thymectomy clinical trial (MGTX), an NIH-sponsored randomized, controlled study of thymectomy plus prednisone versus prednisone alone. METHODS: We applied ultra-performance liquid chromatography coupled with electro-spray quadrupole time of flight mass spectrometry to obtain comparative serum metabolomic and lipidomic profiles at study entry to correlate with treatment response at 6 months. Treatment response was assessed using validated outcome measures of minimal manifestation status (MMS), MG-Activities of Daily Living (MG-ADL), Quantitative MG (QMG) score, or a strictly defined composite measure of response. RESULTS: Increased serum levels of phospholipids were associated with treatment response as assessed by QMG, MMS, and the Responders classification, but all measures showed limited overlap in metabolomic profiles, in particular the MG-ADL. A panel including histidine, free fatty acid (13:0), γ-cholestenol and guanosine was highly predictive of the strictly defined treatment response measure. The AUC in Responders' prediction for these markers was 0.90 irrespective of gender, age, thymectomy or baseline prednisone use. Pathway analysis suggests that xenobiotic metabolism could play a major role in treatment resistance. There was no association with outcome and gender, age, thymectomy or baseline prednisone use. INTERPRETATION: We have defined a metabolomic and lipidomic profile that can now undergo validation as a treatment predictive marker for MG patients undergoing corticosteroid therapy. Metabolomic profiles of outcome measures had limited overlap consistent with their assessing distinct aspects of treatment response and supporting unique biological underpinning for each outcome measure. Interindividual variation in prednisone metabolism may be a determinate of how well patients respond to treatment.

[Robot-assisted Thoracoscopic Surgery for Mediastinal Tumor in Our Department].

In 2019, our facility introduced robot-assisted surgery for mediastinal tumors using da Vinci Si, which was upgrade to da Vinci X and Xi in 2021. Initially, the unilateral thoracic cavity approach was used for robot-assisted surgeries. The unilateral approach has the advantage of facilitating the anatomical recognition of either the left or right side, with the side used selected depending on the location of the lesion. Notably, challenges such as difficulty in recognizing objects were still encountered. To compensate for these shortcomings, our hospital introduced robotic subxiphoid-optical thymectomy, a subxiphoid approach, which has been used for all robot-assisted mediastinal tumor surgeries since its introduction under the guidance of Kyoto Prefectural University of Medicine. Additionally, extended thymectomy, which has been covered by insurance since 2020 and used as the standard surgical procedure for robot-assisted mediastinal tumor surgery at our department, can be performed using the same approach.

[Robot-assisted Minimally Invasive Surgery for Mediastinal Tumors].

The subxiphoid approach in thymectomy provides better visibility around the left brachiocephalic vein than the lateral thoracic approach. Robot-assisted thoracoscopic surgery is easier to parform than video- assisted thoracoscopic surgery for surgery of the upper mediastinum, because the forceps can be moved with many joints. Robot-assisted thymectomy using the subxiphoid approach may be less traumatic and less invasive than median sternotomy. We must continue to devise surgical procedures to make oncologically curative surgery more minimally invasive.

[Robot-assisted Extended Thymectomy via a Bilateral Approach for Patients with Myasthenia Gravis].

Extended thymectomy is a procedure to remove the thymus gland and surrounding adipose tissue, while the traditional approach via a median sternotomy, minimally invasive approaches such as video-assisted thoracoscopic surgery (VATS) and robot-assisted thoracoscopic surgery (RATS) have been adopted. This report described the technique of bilateral approach for extended thymectomy in patients with myasthenia gravis (MG) by robot-assisted thoracoscopic surgery, and also showed the perioperative outcomes and postoperative exacerbation rates of 11 patients. In most patients, score of MG symptom were reduced and levels of anti-acetylcholine receptor antibodies declined postoperatively. In a small number of cases, the safety and efficacy of a RATS bilateral approach for extended thymectomy were confirmed.

[Minimally Invasive Surgery for Mediastinal Diseases in Our Institute:Innovations and Surgical Practice].

Since the early 1990s, minimally invasive surgery has been introduced in many surgical fields. The progress of technology and increased interest in minimally invasive surgery has led to innovation from surgery with a large incision to complete thoracoscopic surgery in many facilities. We started thoracoscopic mediastinal surgery in 1997 and robot-assisted mediastinal surgery in 2021. Considering the approach for anterior mediastinal tumor resection, it is necessary to fully understand tumor size, tumor location, and the existence of the tumor invasion to other organs. Especially in the case of tumors located on the cranial side above the innominate vein or thymectomy with dissection of the superior pole of the thymus, ensuring surgical field visibility is essential. In our institute, from the point of cosmetics, surgical field visibility is ensured using carbon dioxide insufflation and a sternum-lifting method. Although the number of cases is limited, we report our ingenuity and actual implementation of the techniques.