Video-Assisted Thoracic Surgery Thymectomy for Nonthymomatous Myasthenia Gravis

Descriptive analysis of therapeutic outcomes between thoracoscopic and transsternal thymectomy in myasthenia gravis patients from 2011 to 2021

BACKGROUND

Myasthenia gravis is an autoimmune disease with high prevalence of thymus disorders, in which, thymectomy is considered one of the therapeutic approaches in improving the patients' clinical outcomes. Today, thoracoscopic thymectomy has received significant attention than the classic transsternal approach due to fewer complication. Therefore, this study was designed with the aim of investigating the therapeutic outcomes of thymectomy in patients with myasthenia gravis in the Afzalipour Hospital of Kerman between 2011 and 2021.

METHODS

The current study is a descriptive analytical study on patients with myasthenia gravis who underwent surgical thymectomy within 2011-2021. Demographic and clinical characteristics of patients from the time of operation to three years of follow-up were extracted and recorded from clinical records or by phone calls. Data were analyzed using SPSS software.

RESULTS

The data of 70 patients who underwent surgical thymectomy were analyzed. Thymectomy caused a significant reduction in the severity of the disease according to the Osserman classification (P = 0.001). It also significantly reduced the use of corticosteroids (P = 0.001) and IVIG (P = 0.015) compared to the time before the surgery. Sixty-two patients (88.57%) needed to take less medicine than before surgery. Left VATS was associated with less post-operative severity of the disease (P = 0.023). There were only two deaths during the follow-up period.

CONCLUSION

Overall, the findings of the present study demonstrated that thoracoscopic thymectomy is a useful surgical approach that leads to faster recovery, reducing the severity of the disease, need for medication, and complications in patients with myasthenia gravis, In comparison with the transsternal approach.

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.

[The value of thymectomy in the treatment of non-thymomatous myasthenia gravis]

The value of thymectomy in the treatment of non-thymomatous myasthenia gravis has been controversially discussed. The relatively low incidence and prevalence of this disease, the inconsistent documentation in various studies and the necessity of a long-term follow-up to assess the therapeutic effects has made the generation of valid data difficult. The publication in 2016 of the MGTX trial in the New England Journal of Medicine delivered the first randomized controlled data in which patients aged 18-65 years with generalized myasthenia gravis and positive for acetylcholine receptor antibodies showed a significant benefit after surgical resection of the thymus via median sternotomy. Despite a lack of validation of the advantages of thymectomy by minimally invasive surgery from randomized controlled studies, this technique seems to positively influence the outcome of certain patient groups in a similar way. Video-assisted thoracoscopic surgery (VATS) and robotic-assisted thoracic surgery (RATS) using subxyphoidal and transcervical access routes showed not only esthetic advantages but also showed no relevant inferiority in the influence on clinical outcomes of myasthenia gravis compared to median sternotomy; however, not only the benefits and the esthetic results show differences but also the advantages in the various subtypes of myasthenia gravis show divergent prospects of success with respect to remission. The clinical spectrum of myasthenia is heterogeneous with respect to the occurrence of antibodies, the body region affected and the age of the patient at first diagnosis. Ultimately, thymectomy is an effective causal treatment of myasthenia gravis.

Prevalence and risk factors of myasthenia gravis recurrence post-thymectomy

Objectives:

To evaluate the prevalence and the factors associated with recurrence of myasthenia gravis following thymectomy.

Methods:

Six electronic databases which reported on recurrence of myasthenia gravis following thymectomy and/or its risk factors from 1985 to 2018 were searched. Summary prevalence and risk values obtained based on the random effect models were reported.

Results:

Seventy (70) papers containing 7,287 individuals with myasthenia gravis who received thymectomy as part of their management were retrieved. The patients had a mean follow-up of 4.65 years post-thymectomy. The prevalence of myasthenia gravis recurrence post-thymectomy was 18.0% (95% CI 14.7–22.0%; 1865/7287). Evident heterogeneity was observed (I²=93.6%; p<0.001). Recurrence rate was insignificantly higher in male compared with female patients (31.3 vs. 23.8%; p=0.104). Pooled recurrence rates for thymomatous (33.3%) was higher than the rate among non-thymomatous (20.8%) myasthenia gravis patients (Q=4.19, p=0.041). Risk factors for recurrence include older age, male sex, disease severity, having thymomatous myasthenia gravis, longer duration of the myasthenia gravis before surgery, and having an ectopic thymic tissue.

Conclusion:

A fifth of individuals with myasthenia gravis experience recurrence after thymectomy. Closer monitoring should be given to at-risk patients and further studies are needed to understand interventions to address these risks.

Surgical and Neurological Outcome of Minimally Invasive Thymectomy in Patients With Myasthenia Gravis: An Experience of 100 Cases Over 6 Years at a Tertiary Care Center in North India

BACKGROUND

Minimally invasive thymectomy (MIT) is emerging as an effective alternative to open thymectomy in the management of patients with myasthenia gravis (MG). The primary objective of our study is to assess the surgical and neurological outcome of MIT in patients with MG.

MATERIALS AND METHODS

It is a retrospective evaluation of prospectively collected data of 100 patients with MG, who underwent MIT from April 2012 to January 2018 at a tertiary care center in India. Surgical outcome was assessed for success of minimal invasive approach, conversion, perioperative morbidity, and postoperative hospital course. Neurological outcome was assessed, after at least 1 year of follow-up, according to Myasthenia Gravis Foundation of America postintervention status. Factors predicting complete stable remission (CSR) were evaluated.

RESULTS

MIT was successfully performed in 98% patients with 2% conversion. There was no mortality. Overall, 10% of patients had perioperative morbidity with 5% having exacerbation of neurological symptoms. Two of these needed postoperative ventilation, whereas 3 recovered on conservative treatment. Median operative time and hospital stay were 140 minutes and 3 days, respectively. At a median follow-up of 47 months, CSR was seen in 20% with improvement in 73.3%. Overall, 63% patients were taken off steroids and patients requiring 3 drugs decreased by 70.7%. There was significant reduction in the dosage of pyridostigmine (P<0.001), prednisolone (P<0.001), and azathioprine (P=0.002) after thymectomy. Milder disease (Myasthenia Gravis Foundation of America class 1 and 2) predicted CSR on multivariate analysis.

CONCLUSIONS

MIT is a safe and effective procedure that leads to improvement in neurological status with significant reduction in number and dosage of medications after thymectomy. Mild disease predicts CSR.

Prediction of improvement after extended thymectomy in non-thymomatous myasthenia gravis patients

BACKGROUND

It is popularly believed that myasthenia gravis (MG) patients show acetylcholine receptor antibody (AChRAb) production associated with the thymus (germinal centers, approximately 80%). It has been suggested that thymectomy can remove the area of autoantibody production. This study aimed to determine whether the solid volume of the thymus calculated using three-dimensional (3D) imaging could be used to predict the efficacy of thymectomy. Additionally, the study assessed the relationships of the solid volume with germinal centers, change in the serum AChRAb level, postoperative MG improvement, and prednisolone (PSL) dose reduction extent.

METHODS

This retrospective study included 12 consecutive non-thymomatous MG patients (9 female and 3 male patients), who underwent extended thymectomy at our institution over the last 10 years. The mean patient age was 43.3 ± 14.2 years (range, 12-59 years). The study assessed the number of germinal centers per unit area, change in the serum AChRAb level, postoperative MG improvement, PSL dose reduction extent, and solid volume of the thymus.

RESULTS

The number of germinal centers per unit area was significantly correlated with the solid volume of the thymus. The PSL dose reduction extent tended to be correlated with the solid volume.

CONCLUSIONS

Our findings suggest that the solid volume of the thymus can possibly predict steroid dose reduction. Additionally, the solid volume of the thymus in 3D images is the most important indicator for predicting the efficacy of extended thymectomy.

Predictive value of the thymofatty specimen weight index in outcomes of extended thymectomy due to non-thymomatous myasthenia gravis

OBJECTIVES

To evaluate the predictive value of the intraoperative thymofatty specimen weight (TFSW) index on predicting the prognosis of extended thymectomy (ET) for non-thymomatous myasthenia gravis.

METHODS

This is a prospective non-interventional study in which patients who underwent ET between January 2012 and June 2015 were enrolled. Resected thymus and surrounding adipose tissues were weighed using an electronic scale intraoperatively and adjusted to the body surface area (BSA) to calculate the TFSW index. The primary end point was defined as complete stable remission (CSR) according to the Myasthenia Gravis Foundation of America (MGFA) guidelines.

RESULTS

One hundred and eighteen patients who completed postoperative follow-up were included in this study. After a mean follow-up period of 44 months, 68 (57.6%) patients reached clinical CSR. The MGFA class, histopathology and TFSW index were associated with a postoperative CSR in univariate analysis. When the Cox hazard multiple regression model was used, the TFSW index was found to be an independent predictor for CSR (hazard ratio 2.056; 95% confidence interval 1.182-3.576). Based on ROC analysis, an optimal TFSW index cut-off value (35.9 g/m2) with the highest sensitivity and specificity was determined.

CONCLUSIONS

The TFSW index is an important independent predictor for mid-term CSR after ET in non-thymomatous myasthenia gravis patients. During the ET surgery, every effort should be made to take a tissue specimen with a TFSW index more than 35.9 g/m2.

The results of video-assisted thoracoscopic thymectomies in Saint Petersburg, Russia: 20-year of experience

BACKGROUND

During the period from 1996 to 2016, we have performed 281 thymectomies in patients with various diseases of the thymus. In 179 patients, thymic pathology was associated with autoimmune myasthenia gravis (MG), and, in 108 patients, thymoma was diagnosed.

METHODS

The majority of surgeries [254] were performed using video thoracoscopy, 79 of them with an additional cervical approach. The long-term results of video thoracoscopic thymectomies in myasthenic patients were followed up for 1 to 15.5 years.

RESULTS

In 26% of the patients, a complete and stable remission was achieved, in 47%-clinical manifestation improved. Local recurrence of thymoma developed in one patient (0.9%).

CONCLUSIONS

Comparison of postoperative complications and long-term results demonstrated that extended video-assisted thoracoscopic thymectomy (VATS-TE) is a radical, efficient, safe, technically feasible and a well-tolerated surgery. It improves the course of MG as a part of multimodality treatment more efficiently than a conservative therapy alone. The course of MG after VATS-TE shows that the cumulative incidence of remissions/improvements reaches its maximum by the 3rd year after the surgery. VATS-TE is radical and safe for removal of noninvasive thymomas up to 8 cm in size. Additional neck incision (VATS-TE + cervical approach) does not provide further advantages, but rather may be a cause of specific postoperative complications.

Minimally invasive surgical procedures for thymic disease in Asia

Video-assisted thoracic surgery (VATS) procedures for thymic tumors and myasthenia gravis were introduced in Asia in the middle 1990s in at least two regions, Hong Kong and Japan. To overcome difficulties in obtaining a wide view of the anterior mediastinum, several methods for lifting the sternum or anterior chest wall have been presented, mainly by Japanese surgeons. More recently, single port VATS through a subxiphoid incision was also introduced in Japan. The long-term outcome of a VATS extended thymectomy for myasthenia gravis has been shown to be comparable to that of a trans-sternal extended thymectomy, while the long-term outcome of a VATS thymectomy for thymic epithelial tumors remains to be elucidated. Nevertheless, its indication for tumors in an early stage is now widely accepted, and the number of VATS procedures is steadily increasing in Japan and China. Single-port VATS through a subxiphoid incision was developed in Japan and might become accepted as a useful approach in the near future when combined with robot-assisted thoracoscopic surgery. In addition, robot-assisted thoracoscopic surgery for the thymus has also been introduced in some areas in Asia. Although few of those surgical procedures for the thymus have been performed, results obtained thus far indicate that it might be preferable to lung resection. Several novel minimally invasive thymectomy techniques have been invented and developed in Asia, and further advancements in this field by Asian surgeons are anticipated.

Comparative clinical outcomes after thymectomy for myasthenia gravis: Thoracoscopic versus trans-sternal approach

BACKGROUND

Thymectomy is an effective treatment option for long-term remission of myasthenia gravis. The superiority of the trans-sternal and thoracoscopic surgical approaches is still being debated. The aims of this study are to compare postoperative outcomes and neurologic outcomes between the two approaches and to identify prognostic factors for complete stable remission (CSR).

METHODS

Myasthenia gravis patients who underwent thymectomy with trans-sternal or thoracoscopic approach in MahaRaj Nakorn Chiang Mai Hospital, Chiang Mai, Thailand between January1, 2006 and December 31, 2013 were retrospectively reviewed. The endpoints were postoperative outcomes and cumulative incidence function for CSR. The analysis was performed using multilevel model, Cox's proportional hazard model, and propensity score.

RESULTS

Ninety-eight patients were enrolled in this study: 53 in the thoracoscopic group and 45 in the trans-sternal group. There were no significant differences between groups in composite postoperative complications, surgical time, ventilator support days, and length of intensive care unit stay. Intraoperative blood loss and length of hospital stay were significant less in the thoracoscopic group. The CSR and median time to remission were not significantly different between the two approaches. Prognostic factors for CSR were nonthymoma (hazard ratio: 3.5, 95% confidence interval: 1.01-12.22) and presence of pharmacological remission (hazard ratio: 24.3, 95% confidence interval: 3.27-180.41).

CONCLUSION

Thoracoscopic thymectomy is safe and provides good neurologic outcomes in comparison to the trans-sternal approach. Two predictive factors should be considered for CSR. Further prospective studies with a larger sample size and longer follow-up period are warranted to confirm these results.

Eight-year follow-up of patients with myasthenia gravis after thymectomy

PURPOSE

To depict the long-term outcome of patients with myasthenia gravis after thymectomy in combination with immunotherapy, and the factors that may potentially affect the outcome.

METHODS

The 306 patients with myasthenia gravis who underwent extended thymectomy from January 1984 to December 2011 at Tongji Hospital were retrospectively evaluated.

RESULTS

The patients consisted of 174 cases with thymoma and 132 cases without thymoma. Pharmaceutical treatment was tailored for each case during follow-up. Nine patients with thymomatous myasthenia gravis died during the perioperative period, and 297 patients were followed for 8.6 years. By their latest visits, 241 patients (81.1%) gained satisfactory efficacy, 24 cases died (8.1%), and 32 cases (10.8%) remained unchanged or deteriorated. Favorable factors for satisfactory efficacy included the presence of ocular myasthenia gravis before operation, no presence of thymoma, and lack of concomitant diseases. It is interesting to mention that, patients with non-thymomatous myasthenia gravis obtained significantly higher rates of complete stable remission and clinical remission than the patients with thymomatous myasthenia gravis.

CONCLUSIONS

Extended thymectomy combined with immunotherapy is a preferred treatment with a satisfactory long-term remission rate. Patients with non-thymomatous myasthenia gravis have a much more promising prognosis than the patients with thymomatous myasthenia gravis. However, appropriate caution must be taken to discontinue pharmaceutical therapy as relapse remains a major concern after a patient who has already undergone thymectomy becomes symptom-free.

May positron emission tomography reveal ectopic or active thymus in preoperative evaluation of non-thymomatous myasthenia gravis?

BACKGROUND

In myasthenia gravis (MG) both native and ectopic thymic tissue containing germinal centers should show greater metabolism compared to adjacent tissues. We evaluated whether preoperative standardized uptake value (SUV) of 18fluoro-deoxy-glucose on Positron Emission Tomography (PET) might be increased and correlated with the presence of native or ectopic germinal centers.

METHODS

From 2005 to 2012 we performed extended thymectomy in 68 patients with non-thymomatous MG. All patients underwent PET-scan preoperatively and one-year postoperatively. SUVs were assessed in thymic and perithymic regions. Then it was matched with same-age, non-MG and non-neoplastic control group and finally correlated with presence of germinal centers in native thymus or in the ectopic tissue found in the surgical specimens.

RESULTS

Mean SUV was significantly increased in MG patients compared to control group. Thymic SUV was significantly higher in presence of thymic germinal centers [3.5 (2.4-5.0) Vs 2.1 (1.4-2.5), p = 0.021] while perithymic SUV was significantly higher in presence of ectopic germinal centers [3.1 (2.7-3.5) Vs 1.3 (0.9-1.7), p = 0.001]. SUV was significantly correlated with MG score (rho = 0.289, p = 0.017) and marginally with antibodies anti-acetylcholine receptors (rho = 0.129, p = 0.05). At Kaplan Meier analysis, ectopic thymic tissue (p = 0.045) and ectopic germinal centers (p = 0.036) were significant predictors of complete stable remission, but preoperative dichotomized thymic (3.5 or more Vs less) (p = 0.083) and perithymic (2.1 or more Vs less) (p = 0.052) SUVs did not.

CONCLUSIONS

Thymic and perithymic SUVs were significantly higher in patients with MG than non-MG and non-neoplastic patients. Thymic SUV was significantly correlated with the presence of germinal centers. Perithymic SUV resulted significantly correlated with the discovery of ectopic active thymic tissue. Neither thymic nor perithymic high SUVs predicted remission.

Thoracoscopic versus robotic approaches: advantages and disadvantages

The overall advantages of thoracoscopy over thoracotomy in terms of patient recovery have been fairly well established. The use of robotics, however, is a newer and less proven modality in the realm of thoracic surgery. Robotics offers distinct advantages and disadvantages in comparison with video-assisted thoracoscopic surgery. Robotic technology is now used for a variety of complex cardiac, urologic, and gynecologic procedures including mitral valve repair and microsurgical treatment of male infertility. This article addresses the potential benefits and limitations of using the robotic platform for the performance of a variety of thoracic operations.

Thymectomy by video-assisted thoracoscopy versus open surgical techniques

Objective

This study was conducted to compare operative variables and postoperative outcomes in adult patients with myasthenia gravis undergoing thymectomy through 3 different operative techniques: total median sternotomy, partial median sternotomy, and video-assisted thoracoscopy.

Methods

30 patients aged 20–65 years were included in this study. They were subdivided into: group A: 8 patients undergoing thymectomy through a total median sternotomy; group B: 9 patients undergoing thymectomy through a partial median sternotomy; and group C: 13 patients undergoing thymectomy through video-assisted thoracoscopy. Preoperative, intraoperative, and postoperative variables, and mortality were compared among groups.

Results

Preoperative variables were well matched in all groups. Operative time was significantly longer in group C. There was no intraoperative complication in any group. Postoperative length of hospital stay was significantly shorter in group C. Postoperative complications occurred in 3 (10%) patients, mostly in groups A and B. There was no perioperative mortality in any group.

Conclusions

Video-assisted thymectomy is as effective as the traditional open surgical approaches for thymectomy in the management of patients with myasthenia gravis. In addition, the improved cosmesis of the video-assisted approach ideally should lead to earlier thymectomy in patients with myasthenia gravis.

Thymectomy for non-thymomatous myasthenia gravis

BACKGROUND

Treatments currently used for patients with myasthenia gravis (MG) include steroids, non-steroid immune suppressive agents, plasma exchange, intravenous immunoglobulin and thymectomy. Data from randomized controlled trials (RCTs) support the use of some of these therapeutic modalities and the evidence for non-surgical therapies are the subject of other Cochrane reviews. Significant uncertainty and variation persist in clinical practice regarding the potential role of thymectomy in the treatment of people with MG.

OBJECTIVES

To assess the efficacy and safety of thymectomy in the management of people with non-thymomatous MG.

SEARCH METHODS

On 31 March 2013, we searched the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL (2013, Issue 3), MEDLINE (January 1966 to March 2013), EMBASE (January 1980 to March 2013) and LILACS (January 1992 to March 2013) for RCTs. Two authors (RS and GC) read all retrieved abstracts and reviewed the full texts of potentially relevant articles. These two authors checked references of all manuscripts identified in the review to identify additional articles that were of relevance and contacted experts in the field to identify additional published and unpublished data. Where necessary, authors were contacted for further information.

SELECTION CRITERIA

Randomized or quasi-randomized controlled trials of thymectomy against no treatment or any medical treatment, and thymectomy plus medical treatment against medical treatment alone, in people with non-thymomatous MG.We did not use measured outcomes as criteria for study selection.

DATA COLLECTION AND ANALYSIS

We planned that two authors would independently extract data onto a specially designed data extraction form and assess risk of bias; however, there were no included studies in the review. We would have identified any adverse effects of thymectomy from the included trials.

MAIN RESULTS

We did not identify any RCTs testing the efficacy of thymectomy in the treatment of MG. In the absence of data from RCTs, we were unable to do any further analysis.

AUTHORS' CONCLUSIONS

There is no randomized controlled trial literature that allows meaningful conclusions about the efficacy of thymectomy on MG. Data from several class III observational studies suggest that thymectomy could be beneficial in MG. An RCT is needed to elucidate if thymectomy is useful, and to what extent, in MG.

Surgical approaches for stage I and II thymoma-associated myasthenia gravis: feasibility of complete video-assisted thoracoscopic surgery (VATS) thymectomy in comparison with trans-sternal resection

Complete resection could be achieved in virtually all myasthenic patients with Masaoka stage I and II thymoma using the trans-sternal technique. Whether this is appropriate for minimally invasive approach is not yet clear. We evaluated the feasibility of complete video-assisted thoracoscopic surgery (VATS) thymectomy for the treatment of Masaoka stage I and II thymoma-associated myasthenia gravis, compared to conventional trans-sternal thymectomy. We summarized 33 patients with Masaoka stage I and II thymoma-associated myasthenia gravis between April 2006 and September 2011. Of these, 15 patients underwent right-sided complete VATS (the VATS group) by using adjuvant pneuomomediastinum, comparing with 18 patients using the trans-sternal approach (the T3b group). No intraoperative death was found and no VATS case required conversion to median sternotomy. Significant differences between the two groups regarding duration of surgery and volume of intraoperative blood loss (P = 0.001 and P < 0.001, respectively) were observed. Postoperative morbidities were 26.7% and 33.3% for the VATS and T3b groups, respectively. All 33 patients were followed up for 12 to 61 months in the study. The cumulative probabilities of reaching complete stable remission and effective rate were 26.7% (4/15) and 93.3% (14/15) in the VATS group, which had a significantly higher complete stable remission and effective rate than those in the T3b group (P = 0.026 and P = 0.000, respectively). We conclude that VATS thymectomy utilizing adjuvant pneuomomediastinum for the treatment of stage I and II thymoma-associated myasthenia gravis is technically feasible but deserves further investigation in a large series with long-term follow-up.

Factors predicting surgical outcome of thymectomy in myasthenia gravis: A 16-year experience

Aim:

To assess the surgical outcome of myasthenia gravis (MG) following thymectomy and to determine the outcome predictors to such therapeutic approach.

Materials and Methods:

This study is a retrospective review of 80 consecutive thymectomies performed for MG over a 16-year period.

Results:

There were 41 females and 39 males (mean age, 34.32 years) with mean disease duration of 17.45 months prior to surgery. Stagewise distribution of the patients revealed 2.5% in stage I, 48.7% in stage IIA, 33.8% in stage IIB, 8.7% in stage III, and 6.3% in stage IV. The surgical approach was either trans-sternal (n=67) or video-assisted thoracoscopic route (n=13). Follow-up was obtained in 91.2% (n=73) of patients with mean duration of 67.7 months. At their last follow-up, 26.0% were in complete remission, 35.6% were asymptomatic on decreased medications, and 17.8% had clinical improvement on decreased medications. Overall, 79.4% of patients benefited from surgery, 8.2% had unchanged disease status, and 12.3% worsened clinically. Factors influencing favorable outcome include sex, disease stage, gland weight, and preoperative medication with anti-cholinesterase (P<0.05). There was one death in the perioperative period due to septicemia. Two patients died at fourth and seventh month following thymectomy.

Conclusion:

Thymectomy for MG is safe and effective. Certain influencing factors may shape treatment decisions and target higher risk patients.

Robotic-assisted thymectomy with Da Vinci II versus sternotomy in the surgical treatment of non-thymomatous myasthenia gravis: early results

BACKGROUND

The role of thymectomy in myasthenia gravis remains controversial. The remission rate 5years after surgery varies from 13 to 51% in the literature. Sternotomy is the standard technique, though unacceptable by patients because of significant esthetic sequelae. Our objective was to demonstrate that the robot-assisted technique using the Da Vinci Surgical Robot II is at least as efficient and leaves fewer scars than the standard surgical technique.

METHODS

We retrospectively reviewed the data of 31 consecutive patients suffering from myasthenia gravis who underwent surgery in our center from January 1998 to March 2010. Ten patients with thymoma were excluded from this study. Two groups were formed: group 1 corresponding to patients treated with sternotomy, group 2 patients with robot-assisted technique. The duration of the hospital stay, the pain on D1, the degree of improvement at 1year according to Myasthenia Gravis Foundation of America (MGFA) classification, the frequency of relapses, and perioperative treatment were studied.

RESULTS

Our sample consisted of 14 women and seven men. The mean age was 31.3years. The mean delay before surgery was 24months. Group 1 included 15 patients and group 2 had six patients. The complete remission rate at 1year was 9.5% (n=2). Surgery decreased the frequency of relapses after surgery (P=0.08) equally in the two groups. The duration of hospital stay and the pain level on D1 in group 2 were significantly lower than those in group 1 (P=0.02 and P<0.001). The degree of postoperative improvement was not significantly different between the two groups (P=0.31).

CONCLUSION

The results at 1year are fully comparable for sternotomy and the robot-assisted technique. The robot provides additional benefits of minimally invasive techniques: minimal esthetic sequelae in often young patients, less parietal morbidity (including pain), shorter hospital stays. Our complete remission rate, lower than those in the literature, must be considered taking into account the early nature of these results. The surgical robot, because of its many advantages, appears to be a promising technique and should facilitate the early management of these patients.

Multidisciplinary treatment of malignant thymoma

PURPOSE OF REVIEW

Thymomas are the most common tumors of the anterior mediastinum. Although surgery remains the only curative treatment, the use of multimodality therapy for primary unresectable thymomas has led to change the clinical management of these tumors.

RECENT FINDINGS

Nowadays Masaoka stage, WHO, and radical surgical resection are considered by many authors as independent prognostic factors for long-term survival. Radiotherapy may be useful as adjuvant therapy in cases of incomplete surgical resection with microscopic or macroscopic residual disease, or for those patients with locally advanced or metastatic unresectable disease. Chemotherapy is considered a valid option in selected patients with residual disease after local treatments or as a neoadjuvant approach to improve resectability in Masaoka stages III or IV-a thymomas. Currently, no standardized regimen for chemotherapy or agreed timing exists.

SUMMARY

So far, multimodality treatment has been related to low morbidity and long survival rate, but there are still many concerns regarding a different regimen of therapy and the correct timing.

[Minimally invasive thymectomy with videothoracoscopy via the right chest]

BACKGROUND

The authors present the technique and results of minimally invasive thymectomy via the right chest based on their clinical practice.

PATIENTS AND METHODS

Between 1 June 2009 and 31 March 2011 27 patients (22 females, 5 males; mean age 35.1 [17-84] years) underwent thymectomy without sternotomy at the division of thoracic surgery of the Department of Surgery, University of Szeged. Indications were myasthenia gravis in 24 and thymoma in 3 patients. The incisions were the following: two 1.5 cm in the right breast fold and one 3 cm incisions in the axillara. There were no incisions in the neck or no sternotomy was carried out either. Preparation and removal of the thymus were performed by conventional and endoscopic instruments, and a drain was inserted into the right chest cavity up until the mediastinum.

RESULTS

Mean time for surgery was 119 minutes (45-285). There was no conversion and no transfusion needed. Further, there was no surgical mortality or morbidity detected. Mean time for chest drain removal was 2.05 (1-3) days, and mean length of hospital stay was 4.56 (4-7) days. Two patients were admitted to the intensive care unit for myasthenia symptoms. Importantly, myasthenia gravis improved in 91.6% of the patients.

CONCLUSIONS

Minimally invasive thymectomy is a safe procedure with excellent cosmetic results. Improvement in myasthenia gravis was similar to published literature data.

Anesthesia for thoracoscopic surgery

Anesthesia for thoracoscopy is based on one lung ventilation. Lung separators in the airway are essential tools. An anatomical shunt as a result of the continued perfusion of a non-ventilated lung is the principal intraoperative concern. The combination of equipment, technique and process increase risks of hypoxia and dynamic hyperinflation, in turn, potential factors in the development of an unusual form of pulmonary edema. Analgesia management is modelled on that shown effective and therapeutic for thoracotomy. Perioperative management needs to reflect the concern for these complex, and complicating, processes to the morbidity of thoracoscopic surgery.

Treatment of myasthenia gravis

Myasthenia gravis (MG) is an antibody-mediated, neuromuscular transmission disorder, which ranges in clinical manifestations of ocular myasthenia that may be visually disabling to myasthenic crisis with patients suffering life-threatening respiratory insufficiency. MG also has pathophysiologic subgroups based on presence or absence of acetylcholine receptor or muscle-specific kinase antibodies and presence of thymoma. Cholinesterase inhibitors partially improve weakness, but the vast majority of patients require therapies that moderate the autoimmune attack. Mortality of MG has been reduced over the last century, but adverse effects of treatment compromise patient care and rigorous evidence to guide the clinician are lacking.

VATS Thymectomy for Nonthymomatous Myasthenia Gravis Standardized Outcome Assessment Using the Myasthenia Gravis Foundation of America Clinical Classification

Objective

Video-assisted thoracoscopic (VATS) thymectomy has been practiced in Australia for nearly two decades. Our aim was to assess the complete stable remission and asymptomatic disease rates after VATS thymectomy in nonthymomatous myasthenia gravis. There remains doubt that minimally invasive techniques achieve equal remission rates to open maximal operations. Therefore, we report our outcomes using the Myasthenia Gravis Foundation of America (MGFA) Clinical Classification and Kaplan-Meier analysis and compare the results to the literature.

Methods

A retrospective analysis of 78 consecutive patients undergoing right VATS thymectomy between April 1994 and March 2007 at two Thoracic Surgery Units in Melbourne, Australia, was undertaken. Patients with thymoma were excluded. Therefore, 57 patients were followed-up for a minimum of 12 months to apply the MGFA Clinical Classification. VATS thymectomy was performed by a three-port right side technique.

Results

The complete stable remission rate was 15% at 3 years and 28% at 5 years. The asymptomatic disease rate was 59% at 5 years. Median follow-up was 32 months. No prognostic factors for remission were identified. The overall morbidity rate was 14% (8/57).

Conclusions

Right VATS thymectomy achieves comparable remission and asymptomatic disease rates to other minimally invasive and open techniques when compared with studies using either MGFA or older criteria.

Clinical outcome of video-assisted thymectomy for myasthenia gravis and thymoma

We reviewed our experience of video-assisted thoracoscopic thymectomy for myasthenia gravis and thymomas in 119 patients, aged 12-83 years, who were treated between 1998 and 2007. Disease severity was graded using the Osserman classification. To prevent rupture of the tumor capsule and tumor seeding, thymomas were resected using a modified no-touch technique. Thymoma diameters were 10-90 mm (mean, 50 mm). There were no operative deaths, 12 (10%) patients had complications, and 87 (73.1%) improved by 1 or more Osserman grades postoperatively. After follow-up of 1.9-10 years (mean, 4.9 years), 74 (62%) patients remained asymptomatic, with 21% in complete stable remission. Using multivariate regression analysis, there were no statistical differences in median pre- and postoperative Osserman grades with regards to age, sex, duration of symptoms, and presence of thymoma. Video-assisted thoracoscopic thymectomy for myasthenia gravis and selected thymomas can achieve long-term clinical outcomes comparable to those of standard approaches.

Video-assisted thoracic surgery thymectomy: the better approach

Minimally invasive video-assisted thoracic surgery (VATS) thymectomy has evolved significantly over the last decade. The most common indication for VATS thymectomy is the treatment of myasthenia gravis (MG). Video-assisted thoracic surgery thymectomy results in less postoperative pain, better preserved pulmonary function, and improved cosmesis, which can be particularly important to many young female MG patients. Results of VATS thymectomy, in terms of complete stable remission from MG and symptomatic improvement, as well as safety, are comparable with conventional surgical techniques. This more patient-friendly approach would lead to wider acceptance by MG patients and their neurologists for earlier thymectomies and improved outcomes.

Extended videothoracoscopic thymectomy in nonthymomatous myasthenia gravis

Myasthenia gravis (MG) is an uncommon, organ-specific, autoimmune chronic neuromuscular disorder involving the production of autoantibodies directed against the nicotinic acetylcholine receptors (anti-AchRab). It is characterized by weakness and rapid fatigability of voluntary muscles. Thymectomy is performed early in the course of the disease and is indicated for adults less than 70 years old. For many years, the clinical efficacy of thymectomy has been questioned and so far, its benefits in nonthymomatous MG have not been firmly established. Furthermore, the precise mechanisms of action of thymectomy are unknown although possible explanations include removal of the source of continued antigen stimulation and of the AchRab-recruiting B-lymphocytes as well as immunomodulation. However, thymectomy remains indicated in patients with MG and is widely applied to increase the probability of improvement or remission. This article presents the evolution of technical and surgical advances achieved within the authors' program of extended endoscopically assisted thymectomy since 1995. The use of video-assisted thoracic surgery and its variants for performing thymectomy in MG patients is now well established and will continue to evolve for further improvement in the results.

Robot-assisted thoracoscopic thymectomy: perianaesthetic concerns

BACKGROUND

Robot-assisted thoracoscopic thymectomy has brought new challenges to the anaesthesiologists. Here we present a study of 17 patients undergoing robotic thymectomy.

PATIENTS AND METHODS

The present study was a prospective study, which included 17 patients with myasthenia gravis scheduled for robot-assisted thoracoscopic thymectomy. Preoperatively, all scheduled medications were continued along with incentive spirometry.In the operating room, routine monitors were attached. Radial artery cannula and central venous catheter were inserted. Anaesthesia was induced with fentanyl, propofol and sevoflurane in oxygen and nitrous oxide. The neuromuscular blockade was achieved with atracurium. Airway was secured with double lumen tube. The capnography, entropy, neuromuscular junction and temperature monitoring were initiated. After patient positioning, one-lung ventilation was initiated prior to insertion of trocar. Thereafter, the robot was docked and surgery was started. During the surgical dissection, capnomediastinum was created. At the end of the surgery, double lumen tube was changed to single lumen endotracheal tube size. After extubation in ICU, continuous positive airway pressure of 5 mmHg was administered.

RESULTS

Intraoperatively, all patients had transient episodes of arrhythmias and hypotension. The airway pressure increased from 23.7 +/- 2 to 28 +/- 2.7 cmH2O and central venous pressure increased from 12.9 +/- 1 to 19.2 +/- 1.6 mmHg after creation of capnomediastinum. The accidental rent in the right-sided pleura occurred in two patients. Intraoperatively, ventilatory difficulty was encountered in another two patients. One patient had brachial plexus injury. Two patients had hoarseness of voice.

SUMMARY

Refinement of the surgical technique is required to avoid compression by robotic arms on any portion of the patient, particularly the upper extremities. The use of beanbag for positioning of the ipsilateral arm needs to be evaluated further. The double lumen tube is to be positioned in such a way as to avoid any obstacle in the movement of robotic arm. We suggest pulse oximeter and arterial blood pressure monitoring in the abducted arm ipsilateral to the surgical approach. The airway pressure and capnography are to be monitored continuously for detection of capnothorax. Patient of robot-assisted thoracoscopic thymectomy should be observed for any nerve injury.

Thymectomy is more effective than conservative treatment for myasthenia gravis regarding outcome and clinical improvement

BACKGROUND

Myasthenia gravis (MG) is an autoimmune disease with a tremendous impact on the quality of life. Controversies over which patients should be operated on because they may benefit most from thymectomy are still ongoing. The aim of this study was to report our long-term results of patients with MG with comparison of thymectomy and conservative treatment.

METHODS

We report a series of 252 patients with MG. Survival data were generated. Patients were seen in the outpatient clinic, where a modified Osserman score and quality of life score were evaluated at the end of the follow-up period for all surviving patients.

RESULTS

A total of 172 patients with MG were followed after thymectomy or with conservative treatment for a median time of 9.8 years. Patients who underwent thymectomy had significantly greater rates of remission and improvement compared with conservative treatment. Furthermore, they had a significantly greater survival.

CONCLUSION

Currently, different effective modalities of treatment are available in patients with MG. In our long-term follow-up, thymectomy was superior to conservative treatment regarding overall survival, clinical improvement, and remission rate. Therefore, thymectomy should be considered strongly for all patients with generalized MG.

National survey of endoscopic thymectomy: survey report from the Japanese Association for Research on the Thymus

Currently, no specific item regarding endoscopic thymectomy for nonthymomatous myasthenia gravis is listed in the standards of deciding medical service fees. To understand the present situation regarding the medical fee-for-service for endoscopic thymectomy, a questionnaire survey was conducted involving the institutions and members participating in the Japanese Association for Research on the Thymus. Of 101 responding institutions, 18 (18%) reported basically performing endoscopic thymectomy in all qualifying patients, and 32% of the institutions reported mainly performing median sternotomy but sometimes performing endoscopic thymectomy. The methods of approaching endoscopic thymectomy varied among the institutions, but most included endoscopic clips or ultrasound-driven scalpels as well as anterior chest wall lifting devices. A total of 214 patients underwent thymectomy in 2004 in the responding institutions, of whom 77 patients (32%) underwent endoscopic thymectomy. In total, 71% of the responding institutions answered that a specific item regarding endoscopic thymectomy should be listed in the standards for deciding medical service fees.

Thymic Hyperplasia and Thymus Gland Tumors: Differentiation with Chemical Shift MR Imaging1

PURPOSE

To prospectively evaluate chemical shift magnetic resonance (MR) imaging for differentiating thymic hyperplasia from tumors of the thymus gland.

MATERIALS AND METHODS

The institutional review board approved this study; informed consent was obtained and patient confidentiality was protected. The authors assessed 41 patients (17 male, 24 female; age range, 16-78 years) in whom thymic lesions were seen at chest computed tomography. Patients were assigned to a hyperplasia group (n=23) (18 patients with hyperplastic thymus associated with Graves disease and five with rebound thymic hyperplasia) and a tumor group (n=18) (seven patients with thymomas, four with invasive thymomas, five with thymic cancers, and two with malignant lymphomas). T2-weighted fast spin-echo and T1-weighted in-phase and opposed-phase MR images were obtained in all patients and visually assessed. A chemical shift ratio (CSR), determined by comparing the signal intensity of the thymus gland with that of the paraspinal muscle, was calculated for quantitative analysis. Mean CSRs for the patient groups and subgroups were analyzed by using Welch t and Newman-Keuls tests. P<.05 indicated a significant difference.

RESULTS

The thymus gland had homogeneous signal intensity in all 23 patients in the hyperplasia group and in 12 of the 18 patients in the tumor group. The mean CSR (+/- standard deviation) was 0.614 +/- 0.130 in the hyperplasia group and 1.026 +/- 0.039 in the tumor group. Mean CSRs in the patients with a hyperplastic thymus and Graves disease, rebound thymic hyperplasia, thymoma, invasive thymoma, thymic cancer, and malignant lymphoma were 0.594 +/- 0.120, 0.688 +/- 0.154, 1.033 +/- 0.043, 1.036 +/- 0.040, 1.020 +/- 0.044, and 0.997 +/- 0.010, respectively. The difference in CSR between the hyperplasia and tumor groups was significant (P<.001). Mean CSRs in the hyperplasia subgroups were lower than those in the tumor subgroups (P<.001). All hyperplasia group patients had an apparent decrease in thymus gland signal intensity at chemical shift MR imaging; no tumor group patients had a decrease in thymus gland signal intensity.

CONCLUSION

Chemical shift MR imaging can be used to differentiate thymic hyperplasia from thymic tumors.