Paradigm shift in surgical approaches to thymectomy

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.

Outcomes of thoracoscopic thymectomy in patients with juvenile myasthenia gravis

INTRODUCTION

Myasthenia gravis (MG) is an autoimmune disorder of the postsynaptic neuromuscular junction resulting in fatigability of voluntary muscles. There has been increasing evidence supporting thymectomy for MG in adults, and evidence for the role of surgery in pediatric age groups is increasing. The purpose of this study is to describe the outcomes of our patients with juvenile MG undergoing thoracoscopic thymectomy.

MATERIAL AND METHODS

All patients with juvenile MG who underwent thoracoscopic thymectomy at Phoenix Children's Hospital between 1999 and 2014 were included. Patients were diagnosed by their treating neurologist. An Osserman and Genkins criterion was used to classify the severity of the disease and DeFilippi classification was used to assess remission.

RESULTS

Twelve patients underwent thoracoscopic thymectomy for juvenile MG during the time frame studied. Nine (75%) patients had an Osserman stage of IIB, with only two patients with ocular disease. There were no conversions to an open procedure. Seven (59%) patients had normal thymic histology, 4 (33%) had evidence of follicular hyperplasia and one (8%) had involutional changes. The median length of hospital stay was 2days (range 1-5days). There was no 30-day postoperative morbidity, reoperations or mortality. The median length of follow-up was 31months (range, 4-91months) and at the time of their last follow-up; all 12 (100%) patients had a DeFilippi Classification of 3 or better.

CONCLUSION

Surgery for MG in children is indicated for antibody-receptor-positive patients with moderate to severe disease. Thoracoscopic thymectomy is a safe and acceptable treatment for juvenile MG with good disease control. The low morbidity and shorter hospital duration make it an excellent option for consideration.

Left- and right-sided video-assisted thoracoscopic thymectomy exhibit similar effects on myasthenia gravis

BACKGROUND

Unilateral video-assisted thoracoscopic (VATS) thymectomy features less operative trauma, improved cosmesis, and similar efficiency compared with transsternal (TS) thymectomy for treatment of patients with myasthenia gravis (MG). Unilateral VATS thymectomy can be easily performed from either side of the thorax, because thymus is located in the middle of mediastinum. Nevertheless, the side that provides better outcomes remains controversial. This study presents our experience on treatments for MG and reveals the differences between the unilateral VATS thymectomy performed on each side.

METHODS

Eighty-one consecutive patients with MG who underwent TS or VATS thymectomy on either side between January 2003 and December 2012 were enrolled in the study. Clinicopathologic data and surgical outcomes were retrospectively analyzed and compared among different surgical approaches.

RESULTS

TS thymectomy was administered in 50 patients, whereas unilateral VATS approaches were performed on the remaining 31 patients, 15 on the left side and 16 on the right side. The VATS group exhibited a significantly shorter surgery duration (P<0.001), less intraoperative blood loss (P=0.009), shorter postoperative hospital stay (P=0.025), smaller thoracic drainage volume (P=0.033), shorter thoracic drainage duration (P=0.006), and less postoperative complications (P<0.001) compared with the TS group. However, disease remission rates did not significantly differ among the groups (P=0.988). The left-sided group exhibited considerably longer thoracic drainage duration than the right-sided group (P=0.041). Moreover, surgical time (P=0.736), intraoperative blood loss (P=0.281), postoperative hospital stay (P=0.599), thoracic drainage volume (P=0.571), postoperative complications (P=0.742) and therapeutic effect (P=1.000) did not significantly differ among the groups. Multivariate analysis revealed that the ocular type of MG is the only independent factor for clinical remission (P=0.002).

CONCLUSIONS

Unilateral VATS thymectomy can reduce surgical risks and shorten hospitalization duration without threatening the therapeutic effect. This technique can be safely and effectively performed by experienced surgeons in either side of the thorax.

Minimally invasive thymectomy: the Mayo Clinic experience

BACKGROUND

The prevalence of minimally invasive thymectomy (MIT) is increasing and may have significant benefit to patients in terms of morbidity and post-operative recovery. Our aim was to review the Mayo Clinic experience of MIT.

METHODS

We reviewed data from all MIT cases collected in a prospectively maintained database from January 1995 to February 2015. Data were collected regarding patient demographics, perioperative management and patient outcomes.

RESULTS

A total of 510 thymectomies were performed in 20 years. Fifty-six patients underwent MIT (45 video-assisted thoracoscopy, 11 robotic-assisted). The median age was 55 years (range, 23-87 years) with male to female ratio of 25:31. Thymoma was the main pathologic diagnosis in 27/56 patients (48%), with 11/27 (41%) associated with myasthenia gravis (MG), and 16/27 (59%) non-MG. Other pathologies included 1/56 (2%) of each teratoma, lymphoma, lymphangioma, carcinoma and thymolipoma. There were 3/56 (5%) atrophic glands, 4/56 (7%) cysts, 6/56 (11%) benign glands and 11/56 (20%) hyperplastic. Mean blood loss (mL) and operative time (min) were significantly lower in the video-assisted thoracoscopic surgery (VATS) group compared to robotic (65±41 vs. 160±205 mL, P=0.04 and 102±39 vs. 178±53 min, P=0.001, respectively). There was no 30-day mortality. Post-operative morbidity occurred in 7/45 (16%) VATS patients (phrenic nerve palsy 7%, pericarditis 4%, atrial fibrillation 2%, pleural effusion 2%) and 1/11 (9%) robotic (urinary retention requiring self-catheterization). Reoperation was required in 1/3 of VATS patients with phrenic nerve palsy. There was no significant difference in length of hospital stay [VATS 1.5 days (range, 1-4 days) and robotic 2 days (range, 1-5 days) VATS; P=0.05]. Mean follow-up was 18.4 months (range, 1-50.4 months) with no tumor recurrences.

CONCLUSIONS

MIT can be performed with low morbidity and mortality. VATS is associated with reduced blood loss, operative times and earlier hospital discharge compared to robotic MIT.

Video-assisted thymectomy with contralateral surveillance camera: a means to minimize the risk of contralateral phrenic nerve injury

OBJECTIVE

Thymectomy for thymoma has traditionally been performed through midsternotomy that provides excellent exposure for a complete and safe resection. Minimally invasive alternatives have not been extensively evaluated for this disease process because data regarding the long-term oncologic effectiveness of these techniques remain to be established. Furthermore, video-assisted surgery as a unilateral approach may compromise the extension of the resection and could cause irreversible damage to the phrenic nerve of the opposite side. We evaluated the clinical feasibility and safety of a bilateral concomitant video-assisted approach with contralateral surveillance camera in patients undergoing thymectomy for thymoma.

METHODS

Four patients (3 females, 1 male) with thymoma causing myasthenia gravis (MG) were operated thoracoscopically at our institute under general anesthesia with double-lumen endotracheal intubation. The patients were placed in a supine position, and a 5-mm 30-degree lens thoracoscope was introduced into the left pleural space. Two other 10-mm working channels were applied. En bloc thymectomy was then performed, including mediastinal and pericardial fat pads, other tissue, and pleura from the level of the thoracic inlet to the diaphragm. A second 5-mm thoracoscope was inserted into the right hemithorax, and it was kept inside during the entire procedure to allow lateral surveillance of the extension and safety of the resection. Carbon dioxide insufflation and valved ports were used.

RESULTS

The duration of the operation was 90 ± 72 minutes. Complete resection was achieved in all patients without any nerve injury. There were no perioperative adverse events. Gradual remission from extremity and ocular weakness was achieved after recovery.

CONCLUSIONS

The ultimate surgical goal of thymectomy is to completely remove the gland and anterior mediastinal tissue without nerve injury. Bilateral concomitant video-assisted thoracic thymectomy with a contralateral surveillance camera was found feasible and safe. Given the capability of our technique to perform a complete and extensive thymectomy associated with less invasiveness and beneficial effects, there seems to be a role for minimally invasive thymectomy in the treatment of thymoma.

Unilateral extended thoracoscopic thymectomy for nontumoral myasthenia gravis--a new standard

Myasthenia gravis (MG) is a heterogeneous disorder with a fluctuating, clinical, pathologic, and immunobiological picture. Today, it is believed that effective treatment of MG must include both immunosuppression and surgery. Thymectomy is recommended by neurologists for patients with nontumoral MG as an option to increase the probability of remission or improvement. Currently, thoracoscopic thymectomy is considered a good alternative to the standard open approach because of its higher rate of acceptance, low morbidity, and high efficacy, as measured by complete stable remission rates. We present a review of the experience of unilateral extended thoracoscopic thymectomy for nontumoral MG, a technique that could became a new standard in the complex management of MG treatment.

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.

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.

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.

Robotic-assisted thymectomy

Thymectomy is an established therapy for myasthenia gravis. Minimally invasive surgery for thymectomy has been reported, but not clearly shown to be equivalent to open resection. Robotic-assisted thymectomy may provide the benefit of a full resection of thymic tissue and anterior mediastinal tissue for the treatment of myasthenia gravis by a minimally invasive approach. We present a review of the experience of robotic thymectomy.

Long-term follow-up after thymectomy for myasthenia gravis: thoracoscopic vs open

PURPOSE

The aim of this study was to determine if patients are in remission or weaning off medication after thymectomy for myasthenia gravis (MG) and to examine the thoracoscopic versus open approaches.

METHODS

A retrospective review of all patients who underwent thymectomy for MG at a tertiary referral center between 1992 and 2004 (N = 14). Six patients (42.9%) underwent thoracoscopic resection. Eight patients underwent open resection; 5 (35.7%) had median sternotomy and 3 (21.4%) by transcervical approaches. Follow-up was obtained in 12 (85.7%) of 14 patients by both chart review and telephone. The mean follow-up was 43.0 months (range, 4-111 months). Statistical significance was determined by Student's t test or Fisher's Exact Test.

RESULTS

The thoracoscopic group had a mean operating time of 138.8 minutes compared with 139.8 minutes in the open group (P = .9). The thoracoscopic group had a mean estimated blood loss of 7.5 mL compared with 52.5 mL in the open group (P = .02). The mean length of stay for the thoracoscopic group was 1.5 days (range, 1-2 days) and was 10.6 days (range, 3-41 days) in the open group (P = .13). Three (60%) of 5 patients were entirely off medication in the thoracoscopic group at the time of follow-up compared with 3 (50%) of 6 patients in the open group (P = 1.0). In the thoracoscopic group, 5 (83.3%) of 6 were in class 1 to 3 of the DeFilippi classification (complete remission or improved with decreased medication requirements). One patient had no change in symptoms (class 4). In the open group, 5 (83.3%) of 6 were classified as DeFilippi 1 to 3 at the time of follow-up, and one patient had worsening symptoms (class 5).

CONCLUSIONS

Both thoracoscopic and open approaches to thymectomy in patients with MG are effective, with more than 80% of patients in both groups in remission or with improvement at the time of follow-up. The thoracoscopic group has the added benefits of decreased estimated blood loss, decreased length of hospital stay, and improved cosmesis. We advocate the thoracoscopic approach for thymectomy in the treatment of juvenile MG.

Video-Assisted Thoracic Surgery Thymectomy for Nonthymomatous Myasthenia Gravis

STUDY OBJECTIVES

Minimal-access thymectomy has become increasingly popular as surgical treatment for patients with nonthymomatous myasthenia gravis (NTMG) because of its comparable efficacy, safety, and lesser degree of tissue trauma compared with conventional open surgery. We reviewed and analyzed our data on video-assisted thoracic surgery (VATS) thymectomy and present the clinical outcomes according to the Myasthenia Gravis Foundation of America classification.

DESIGN

A retrospective review of VATS thymectomy for NTMG in a university hospital over a 12-year period. Data were collected from the medical records and supplemented with telephone surveys. The impact of surgery and other variables potentially affecting complete stable remission (CSR) were calculated using Kaplan-Meier survival curves; comparisons between survival curves was performed using the log-rank test.

RESULTS

A total of 38 consecutive patients underwent VATS thymectomy for NTMG. Median postoperative stay was 3 days. Pathologic examination revealed thymic hyperplasia in 61.1% of cases, normal thymus in 22.2%, and thymic atrophy in 16.6%. There was no perioperative mortality; complications occurred in four patients. After a median follow-up of 69 months, 91.6% of patients experienced improvement, with crude CSR achieved in 22.2%. Kaplan-Meier survival curve demonstrated a 75% CSR rate at 10-year follow-up. On univariate analysis, only disease duration < or = 12 months (p = 0.03) was associated with a statistically significant improvement in CSR.

CONCLUSIONS

VATS thymectomy for NTMG results in symptomatic improvement in the vast majority of patients, with a high rate of CSR. The procedure is associated with low morbidity and no perioperative mortality. Future studies on thymectomy for myasthenia gravis should be reported in a standardized manner to allow accurate comparisons between results in the absence of randomized prospective trials.