Assessment of the risks of a myasthenic crisis after thymectomy in patients with myasthenia gravis: a systematic review and meta-analysis of 25 studies

Minimally invasive thymectomy for patients with thymoma: surgical, oncological and neurological outcomes

Background

Traditionally, sternotomy has been the gold standard approach for the treatment of thymomas. However, interest in minimally invasive techniques such as video-assisted and robot-assisted thymectomy is gaining momentum. Concerns have been raised over the possibility of en-bloc resection using minimal access techniques due to limited working space and increased tumour manipulation leading to tumour breach and recurrence.

Methods

An observational cohort study was conducted at a tertiary referral centre from 1 April 2012 to 31 December 2020 and followed up until 31 March 2023. Consecutive patients of thymoma were evaluated for demography, symptoms and imaging preoperatively and included for the study. Post minimally invasive thymectomy, surgical, neurological and oncological outcomes were evaluated through out-patient and telephonic follow-up.

Results

Fifty-two patients underwent minimally invasive thymectomy. Video-assisted thoracoscopic surgery for thymectomy was used in 49 patients (94.2%) with 3 (5.8%) patients undergoing robot-assisted thoracoscopic surgery. Median tumour size was 4 cm (interquartile range (IQR) 3-5) with a median operative duration of 150 min (IQR 120-180), blood loss of 135 ml (IQR 42.5-250), post-operative stay of 3 days (IQR 2-4) and no 30-day surgery related morbidity and mortality. Annual contrast-enhanced computed tomography imaging, available in 46 (88.5%) patients, showed no recurrence at a median follow-up of 43 (IQR, 21-75) months. No symptoms suggesting recurrence was noted at a median clinical follow-up of 57 (IQR 44-95.5) months and 88.5% patients were expected to survive a period of 10 years.

Conclusion

Minimally invasive thymectomy is technically feasible with minimal morbidity and acceptable intermediate-term oncological outcomes in patients suffering with thymoma.

Trial registration

Institute ethical committee approval: Ref no. IECPG-551/14.11.2018.Clinical Trial Registry of India: Ref no. CTRI/2019/04/018784.

Surgical management of thymic tumors: a narrative review with focus on robotic-assisted surgery

Background and Objective

Thymic epithelial tumors, including thymomas and thymic carcinomas, represent the most common mediastinal tumors and account for up to 50% of all anterior mediastinal tumors. For early stages of these thymic tumors, complete resection of the entire thymus is the recommended treatment. The transition from open surgery to video-assisted thoracoscopic surgery (VATS) and recently to robotic-assisted thoracic surgery (RATS) has fundamentally altered the treatment of thymic tumors. While RATS has been widely implemented due to its many advantages including good visualization with magnification and three-dimensional vision, improved maneuverability and precise instrument control, different techniques have been described. This narrative review focuses on the main approaches and outcomes of RATS thymectomy. It compares the technical, perioperative and clinical outcomes of RATS thymectomy, in particular, with VATS and open thymectomy.

Methods

A non-systematic review for full text studies written in the English language was conducted using the PubMed search engine and literature was summarized.

Key Content and Findings

We present an overview of robotic-assisted resection for thymomas and review the main approaches and outcomes of RATS thymectomy. Critical points of the RATS approach, including surgical specifics and pitfalls, are presented. Technical advantages and disadvantages of each technique are discussed. The perioperative and clinical outcomes of RATS thymectomy are compared, where possible, to those for VATS and open thymectomy. Currently, retrospective analyses demonstrate comparable or even more favorable outcomes following a RATS approach in comparison to VATS and open approaches in terms of operating time, conversion rates, intraoperative complications, completeness of resection and mortality. Certain analyses also report better outcomes for patients undergoing RATS thymectomy in terms of blood loss, postoperative complications, duration of pleural drainage and length of hospital stay compared to VATS and open thymectomy.

Conclusions

Overall, RATS has shown promising results and could become the preferred technique for resection of thymic tumors. It shows good outcomes compared to VATS and open thymectomy in the current literature. However, especially for extended tumors with the need for extended resection and reconstruction, open thymectomy remains a valuable approach.

Physiological and pathological roles of the thymus and value of thymectomy in myasthenia gravis: a narrative review

Background and Objective

Myasthenia gravis (MG) is a well-elucidated autoimmune disorder affecting the neuromuscular junction. Given the relationship between MG and thymic pathologies, with T cell and antibody-mediated pathogenesis, surgical (i.e., thymectomy) and non-surgical approaches remain a mainstay of management of the disease. This review seeks to outline the involvement of the thymus in the development of lymphocytes leading to MG.

Methods

Different databases were searched exploring the role of thymectomy in treatment and outcomes in various MG patient subpopulations, including in ocular versus generalized disease, different age groups, and antibody status.

Key Content and Findings

Overall, the findings of multiple studies and reviews provide evidence to support the efficacy and long-term success of thymectomy in the management of MG; outcomes have included remission status, symptom severity, and need for adjunctive therapy. However, the heterogeneity in the MG population suggests that there are multiple factors that may confound the results of thymectomy and still need further examination. Separately, other autoimmune diseases develop following thymectomy, and further research is required to elucidate this susceptibility. Finally, our review will discuss the different surgical approaches for thymectomy, including their advantages, limitations, and perioperative complications.

Conclusions

Overall, in light of the known pathogenesis and association of the thymus with MG, thymectomy remains an extremely effective approach for long-term management and improved clinical outcomes.

Summary of the best evidence for the prevention and management of myasthenic crisis after thymectomy

Background

Myasthenic crisis (MC) may occur after thymectomy in patients with myasthenia gravis (MG), but effective preventive interventions can reduce the occurrence of this complication. Previous research on MC focused on risk factors, emergency treatment, etc., which was relatively scattered and did not form a comprehensive management framework. This study sought to retrieve and summarize the relevant evidence on the prevention and management of postoperative MC to provide a theoretical reference for clinical medical staff.

Methods

According to the evidence pyramid model, relevant articles were retrieved from UpToDate, British Medical Journal (BMJ) Best Practice, World Health Organization (WHO), Scottish Intercollegiate Guidelines Network (SIGN), Guidelines International Network (GIN), Australian Joanna Briggs Institute (JBI) Healthcare Database, Medlive, PubMed, Cochrane Library, Embase, Web of Science, China National Knowledge Infrastructure (CNKI), and Wanfang. The types of evidence included clinical guidelines, expert consensus articles, clinical decisions, systematic reviews, and randomized controlled trials (RCTs). The quality evaluations were conducted using the Appraisal of Guidelines for Research and Evaluation II (AGREE II) evaluation tool for guidelines, the Australian JBI Evidence-Based Healthcare Center evaluation tool for expert consensus articles, the Critical Appraisal for Summaries of Evidence (CASE) evaluation tool for clinical decisions, the Assessment of Multiple Systematic Reviews (AMSTAR) evaluation tool for systematic reviews, and the Cochrane risk-of-bias tool for RCTs.

Results

A total of 12 articles were included in this study, including three clinical guidelines, three expert consensus articles, three clinical decisions, two systematic reviews, and one RCT. From these articles, we summarized 39 pieces of evidence on the prevention and management of postoperative MC.

Conclusions

This study summarized the best evidence on the prevention and management of postoperative MC and provided to clinical staffs evidence-based clinical approaches to help reduce the incidence of this complication.

High indirect bilirubin levels as an independent predictor of postoperative myasthenic crisis: a single-center, retrospective study

Background

Thymectomy is an efficient and standard treatment strategy for patients with myasthenia gravis (MG), postoperative myasthenic crisis (POMC) is the major complication related to thymectomy and has a strongly life-threatening effect. As a biomarker, whether the bilirubin level is a risk factor for MG progression remains unclear. This study aimed to investigate the association between the preoperative bilirubin level and postoperative myasthenic crisis (POMC).

Methods

We analyzed 375 patients with MG who underwent thymectomy at Tangdu Hospital between January 2012 and September 2021. The primary outcome measurement was POMC. The association between POMC and bilirubin level was analyzed by restricted cubic spline (RCS). Indirect bilirubin (IBIL) was divided into two subgroups based on the normal upper limit of IBIL, 14 μmol/L.

Results

Compared with non-POMC group, IBIL levels were significantly higher in patients with POMC. Elevated IBIL levels were closely associated with an increased risk of POMC (p for trend = 0.002). There was a dose-response curve relationship between IBIL levels and POMC incidence (p for non-linearity = 0.93). However, DBIL levels showed a U-shaped association with POMC incidence. High IBIL level (≥14 μmol/L) was an independent predictive factor for POMC [odds ratio = 3.47, 95% confidence interval (CI): 1.56-7.8, p = 0.002]. The addition of high IBIL levels improved the prediction model performance (net reclassification index = 0.186, 95% CI: 0.039-0.334; integrated discrimination improvement = 0.0345, 95% CI: 0.005-0.065).

Conclusion

High preoperative IBIL levels, especially those exceeding the normal upper limit, could independently predict the incidence of POMC.

Measuring the Efficacy of Thymectomy for Pediatric Myasthenia Gravis Across Tertiary Children's Hospitals

BACKGROUND

Thymectomy is a treatment for pediatric myasthenia gravis, but the efficacy over time is unknown. Multi-institutional data are also lacking. Therefore, the objective of this study was to determine the efficacy of thymectomy for pediatric myasthenia gravis using medication burden and health care utilization as proxies for disease severity.

METHODS

This was a cross-sectional study of the Pediatric Health Information System database among children who underwent thymectomy at one of 49 children's hospitals from 2004 to 2022. Differences in annual median number of doses of myasthenia-related medications, admissions, and health care costs in the year before thymectomy to three years after were compared. A comparison cohort that did not undergo thymectomy was utilized. Medians were compared using the Wilcoxon signed-rank test. Generalized linear regression estimated the effect of surgical approach on outcomes.

RESULTS

A total of451 patients (238 patients who underwent thymectomy and 213 nonthymectomy patients) were identified. Following thymectomy, the decrease in annual median total number of myasthenia-related doses was 12.0 (interquartile range: 6 to 31) (P < 0.001). The decrease in number of annual admissions was 2.0 (1 to 4) (P < 0.001), which represented a cost difference of $5292 ($3533 to $8681) (P < 0.001). No differences were observed in the control cohort. In a generalized linear regression model, surgical approach was not associated with the efficacy of thymectomy (P = 0.55).

CONCLUSIONS

Thymectomy is an effective treatment for pediatric myasthenia gravis, evidenced by the decreased medication burden and health care utilization after surgery. Surgical approach did not influence the success of surgery. Thymectomy should be considered earlier in the treatment algorithm.

Analysis of influencing factors of perioperative myasthenic crisis in 387 myasthenia gravis patients without thymoma in a single center

OBJECTIVE

To study the influencing factors of myasthenic crisis in non-thymoma myasthenia gravis (MG) patients during perioperative period.

METHODS

We retrospectively analyzed a total of 387 non-thymoma MG patients who underwent extended thymoma resection in the Department of Thoracic Surgery of Beijing Hospital from February 2011 to December 2021, recorded ASA score, Osserman classification, preoperative course, pyridostigmine dosage, operation method, operation time, and intraoperative blood loss, then analyzed the factors associated with postoperative myasthenic crisis by univariate and multivariate logistic regression.

RESULTS

Osserman classification IIB + III + IV (P < 0.001), history of myasthenic crisis (P = 0.013), pyridostigmine dosage greater than 240 (P < 0.001), ASA score 2 and 3 (P = 0.001) are independent risk factors for myasthenic crisis.

CONCLUSION

Patients with poor Osserman classification, history of myasthenic crisis before surgery, larger preoperative dosage of pyridostigmine, and higher ASA scores should be highly alert to the occurrence of postoperative myasthenic crisis.

Analysis of influencing factors of postoperative myasthenic crisis in 564 patients with myasthenia gravis in a single center

OBJECTIVE

To study the influencing factors of myasthenic crisis in patients with myasthenia gravis during perioperative period.

METHODS

A total of 564 myasthenia gravis (MG) patients who underwent standard expanded resection of thymoma/thymoma in the Department of Thoracic Surgery of Beijing Hospital from January 2011 to March 2022 were retrospectively included in the study. Clinical indicators such as gender, age, thymoma, American Society of Anesthesiologists (ASA) score, operation time, intraoperative blood loss, and some others were recorded.

RESULTS

Osserman-stages IIB + III + IV (odds ratio [OR] 16.091, 95% confidence interval [CI] 5.170-50.076, p value < 0.001), the dosage of pyridostigmine bromide more than 240 mg (OR 6.462, 95% CI 3.110-13.427, p value < 0.001), ASA score 2 and 3 (OR 3.203, 95% CI 1.461-7.020, p value = 0.004), low diffusion lung capacity for carbon monoxide (DLCO%) (OR 0.981, 95% CI 0.963-1.000 p value = 0.049), and blood loss greater than 1000 ml (OR 16.590, 95% CI 1.911-144.011, p value = 0.011) were independent risk factors for myasthenic crisis.

CONCLUSIONS

Patients with poor Osserman stages, higher preoperative dosage of pyridostigmine bromide, higher ASA score, poor pulmonary function (low DLCO%), and more intraoperative bleeding should be highly vigilant for the occurrence of postoperative myasthenic crisis.

Anesthetic management of a patient with subclinical myasthenia gravis who underwent a thymectomy: a case report

Background

Some individuals with subclinical myasthenia gravis (MG) are positive for serum anti-acetylcholine receptor antibodies, without neurological symptoms. There are no anesthetic management guidelines for subclinical MG. We report the anesthetic management of a patient with subclinical MG who underwent a thymectomy.

Case presentation

A 57-year-old female with subclinical MG was scheduled for an extended thymectomy. Anesthesia was induced and maintained with mainly propofol and remifentanil. We administrated the minimum amount of rocuronium with reference to train-of-four (TOF) monitoring when a neuromuscular relaxant is needed. Although the prolonged effect of rocuronium was observed, the TOF ratio had already recovered to 100% before the tracheal extubation. Postoperative analgesia was performed by a continuous epidural infusion of levobupivacaine.

Conclusion

We reported the anesthetic management of a patient with subclinical MG who underwent a thymectomy. Further research is necessary to clarify subclinical MG patients' sensitivity to rocuronium.

Childhood-Onset Myasthenia Gravis Patients Benefited from Thymectomy in a Long-Term Follow-up Observation

INTRODUCTION

 The effect of thymectomy on the treatment of childhood-onset myasthenia gravis (CMG) remains debatable. The objective of this study was to evaluate the clinical outcome and relevant prognostic factors of thymectomy for CMG patients.

MATERIALS AND METHODS

 A total of 32 CMG patients who underwent thymectomy before 18 years of age were included in this retrospective study. Clinical state following thymectomy was assessed by quantified myasthenia gravis (QMG) scores, myasthenia gravis-related activities of daily living (MG-ADL) scores, and Myasthenia Gravis Foundation of America postintervention status. Repeated-measures analysis of variance (ANOVA) examined the changes in postoperative scores during the 5-year follow-up. Univariate logistic regression was applied to identify factors associated with short-term (1-year postoperation) and long-term (5-year postoperation) clinical outcomes.

RESULTS

 Repeated-measures ANOVA showed that QMG scores (F = 6.737, p < 0.001) and MG-ADL scores (F = 7.923, p < 0.001) decreased gradually with time. Preoperative duration (odds ratio [OR] = 0.85, 95% confidence interval [CI]: 0.73-1.00, p = 0.043), gender (OR = 0.19, 95% CI: 0.04-0.94, p = 0.041), and MG subgroup (OR = 13.33, 95% CI: 1.43-123.99, p = 0.023) were predictors for 1-year postoperative prognosis. Shorter disease duration (OR = 0.82, 95% CI: 0.70-0.97, p = 0.018) and generalized CMG (OR = 6.11, 95% CI: 1.06-35.35, p = 0.043) were found to have more favorable long-term results.

CONCLUSION

 Our results suggest that thymectomy is effective in treating CMG. Thymectomy could be recommended for CMG patients, especially for patients in the early course of GMG.