Video-assisted completion thymectomy in refractory myasthenia gravis

[Rethymectomy in patients with myasthenia gravis and recurrent thymoma]

OBJECTIVE

To analyze efficacy and safety of rethymectomy in patients with pathology of thymus.

MATERIAL AND METHODS

Nine patients (2 males and 7 females) underwent rethymectomy in the thoracic surgery department of the Hertzen Research Institute of Oncology for the period from March 2009 to December 2019. Initial thymectomy for myasthenia gravis was performed in 6 patients, for thymoma without myasthenia - in 3 patients. Age of patients varied from 27 to 75 years (median 42.8 years). Myasthenia manifested at the age of 25-61 years (median 29.2 years). Period between manifestation and thymectomy varied from 6 to 24 months (median 12.6 months). MGFA grade IIIa was in 1 patient, grade IIIb - in 1, grade IVa - in 1, grade IVb - in 2, grade V - in 1 patient. Rethymectomy was performed via sternotomy in 4 cases, through thoracoscopy - in 5 patients.

RESULTS

Postoperative complications occurred in 2 (22.2%) patients. Biopsy revealed residual thymic tissue in all patients. Median follow-up after rethymectomy was 30.2 months (range 12-132 months). Complete stable remission was achieved in 3 (50.0%) patients, remission - in 2 cases, partial remission - in 1 patient. Median dose of steroids before rethymectomy was 40 mg (range 16-96 mg), median dose after rethymectomy - 8 mg (range 0-24 mg). Differences were significant (p=0.04). All patients operated on for thymoma or recurrence are alive within 12-124 months after rethymectomy.

CONCLUSION

Rethymectomy is a safe and effective treatment option for patients with refractory myasthenia gravis (especially in case of detected residual thymic tissue) or recurrent thymoma. Radical surgery for recurrent thymoma ensures favorable survival.

Subxiphoid completion thymectomy for refractory non-thymomatous myasthenia gravis

Background

Completion thymectomy may be performed in patients with non-thymomatous refractory myasthenia gravis (MG) to allow a complete and definitive clearance from residual thymic tissue located in the mediastinum or in lower neck. Hereby we present our short- and long-term results of completion thymectomy using subxiphoid video-assisted thoracoscopy.

Methods

Between July 2010 and December 2017, 15 consecutive patients with refractory non-thymomatous myasthenia, 8 women and 7 men with a median age of 44 [interquartile range (IQR) 38.5–53.5] years, underwent video-thoracoscopic completion thymectomy through a subxiphoid approach.

Results

Positron emission tomography (PET) showed mildly avid areas [standardized uptake value (SUV) more than or equal to 1.8] in 11 instances. Median operative time was 106 (IQR, 77–141) minutes. No operative deaths nor major morbidity occurred. Mean 1-day postoperative Visual Analogue Scale value was 2.53±0.63. Median hospital stay was 2 (IQR, 1–3.5) days. A significant decrease of the anti-acetylcholine receptor antibodies was observed after 1 month [median percentage changes −67% (IQR, −39% to −83%)]. Median follow-up was 45 (IQR, 21–58) months. At the most recent follow-up complete stable remission was achieved in 5 patients. Another 9 patients had significant improvement in bulbar and limb function, requiring lower doses of corticosteroids and anticholinesterase drugs. Only one patient remained clinically stable albeit drug doses were reduced. One-month postoperative drop of anti-acetylcholine receptor antibodies was significantly correlated with complete stable remission (P=0.002).

Conclusions

This initial experience confirms that removal of ectopic and residual thymus through a subxiphoid approach can reduce anti-acetylcholine receptor antibody titer correlating to good outcome of refractory MG.

Robotic-Extended Rethymectomy for Refractory Myasthenia Gravis: A Case Series

To assess the safety and efficacy of robotic-extended rethymectomy in selected refractory myasthenia gravis (MG) patients with suspected residual thymic tissue. Robotic-extended rethymectomy was performed in 6 MG patients with seropositive acetylcholine receptors (AChR) antibody who had undergone a previous thymectomy (1 cervicotomy, 2 video-assisted thoracoscopic surgeries, and 3 sternotomies). The median observation time before robotic rethymectomy was 108 (24-171) months. The main outcomes were perioperative morbidity, mortality, conversion to open surgery, and clinical outcomes according to the Myasthenia Gravis Foundation of America Post-Intervention Status (MGFA-PIS). Before rethymectomy, all patients required immunosuppressants and 5 patients (83.3%) required intravenous immune globulin and/or plasma exchange to control the symptoms. The median specimen weight was 24.5 (14-144) g after rethymectomy, and residual thymic tissue was found in 5 patients (83.3%). No conversion to open surgery or perioperative morbidity and mortality was observed. With a median follow-up time of 46.5 (13-155) months, 3 patients (50%) achieved "improved" and 3 (50%) were "unchanged" according to the MGFA-PIS. Compared with preoperative use, the median daily dose of corticosteroids statistically decreased (25 [7.5-60] vs 0 [0-5] mg, P = 0.002) without significant change in azathioprine use (100 [0-200] vs 50 [0-150] mg, P = 0.360). AChR antibody positive MG patients with a treatment refractory long-term course after thymectomy might have remaining thymic tissue with the 2 commonly associated thymus pathologies, thymoma, and follicular hyperplasia. Robotic-extended rethymectomy might be considered as a safe and beneficial treatment option in these patients.

Does repeat thymectomy improve symptoms in patients with refractory myasthenia gravis?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was: Does repeat thymectomy improve symptoms in patients with refractory myasthenia gravis after thymectomy? A total of 189 papers were found using the reported search, of which seven represented the best evidence to answer the clinical question. The outcome measures included operative mortality and morbidity, as well as long-term remission rate. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. All the studies were small (4-21 patients), retrospective, single institutional case series. There was considerable heterogeneity in the studies. The interval between the first and second operation ranged from less than a year to over 10 years. The operative approach of the initial operation included transcervical, trans-sternal and substernal approaches. The maximal medical therapy received by the patients prior to reoperation varied from anticholinesterase alone to cytotoxic therapy and regular plasmapheresis. The severity of symptoms ranged from Osserman Class IIa to V. The operative approach to re-thymectomy included resternotomy, thoracoscopy and a combination of both. There was no perioperative mortality. One study reported injury to the innominate vein at resternotomy in 3 (14.3%) patients. One study reported myasthenic crisis in 2 patients in the postoperative period. Only one study reported complete remission in 2 patients. In general, however, 52-95% of patients reported some improvement. There was no consistent, objective measure of improvement in these studies. We conclude that repeat thymectomy for patients with refractory myasthenia gravis after previous thymectomy is safe especially for patients whose first procedure was transcervical. Complete remissions are rare but, in these small series, 60-70% of patients report improvement. Clinical improvement appears to be associated with the presence of residual thymic tissue at the second operation, but these cannot be reliably identified on preoperative imaging. Patient selection remains driven by symptoms.

Experience With the “Da Vinci” Robotic System for Thymectomy in Patients With Myasthenia Gravis: Report of 33 Cases

BACKGROUND

Our initial experience in applying robotic-assisted technologies for the treatment of myasthenia gravis (MG) in patients without thymoma is reported.

METHODS

from April 2002 to October 2004, 33 patients (24 females and 9 males; mean age, 41 years), with clinical nonthymomatous myasthenia gravis, underwent robotic thoracoscopic thymectomy using the "da Vinci" (Intuitive Surgical, Inc, Mountain View, CA) system and adopting a 3 port, left-sided approach.

RESULTS

Mean operative time was 120 minutes. No intraoperative complications or surgical mortality is reported and postoperative complications occurred in two patients (6%). Mean hospital stay was 2.6 days (range, 2-14 days). Histologic analysis of surgical specimens revealed 23 hyperplasia, 4 normal thymus, 4 atrophy, and 2 thymomas; in 12 patients (36.3%) ectopic thymic tissue was found. Follow-up evaluation of the first 24 patients (mean, 23.8 months; range, 12-31 months) showed that 4 patients (16.7%) had complete remission and 18 (75%) had significant clinical improvement for a global benefit rate of 91.7%.

CONCLUSIONS

In patients with MG, robot-assisted thymectomy can be performed safely and efficiently. The improved visualization and dexterity of this instrument and its advanced technology may facilitate the minimally invasive approach to the thymus. We prefer to use the left-sided approach because it provides an enhanced visualization of the aortic window and it reduces the probability of phrenic nerves injury. A longer follow-up is necessary to verify long-term clinical results.

Video-assisted thoracoscopic thymectomy in juvenile myasthenia gravis

As video-assisted thoracoscopic surgery for thymectomy has been reported to be as effective as traditional open surgical approaches in predominantly adult patients with myasthenia gravis, we applied this procedure to juvenile patients with this condition. Six patients underwent total thymectomy using the video-assisted technique (1997-98). Six patients in whom a median transsternal approach was used (1989-95) formed the comparison group. The two patient groups were similar in terms of age at thymectomy and preoperative clinical severity. There were no serious perioperative complications in either group. Minimum post-thymectomy duration of follow-up in the video-assisted thoracoscopic surgery patients was 2.3 years (mean 2.7 years), with all patients clinically improved over their baseline status. Preliminary results suggest that video-assisted thymectomies are comparably effective to transsternal procedures in treating generalized juvenile myasthenia gravis and can be safely performed in children as young as 20 months of age. In addition, video-assisted surgeries are less invasive than transsternal approaches, significantly shorten the postoperative hospital stay, and have superior cosmetic results.

Thoracoscopic completion thymectomy in refractory nonthymomatous myasthenia

BACKGROUND

The aim of this study was to assess the efficacy of thoracoscopic completion thymectomy in patients with refractory nonthymomatous myasthenia.

METHODS

Eight patients were operated upon after transcervical (n = 6) or transsternal (n = 2) thymectomy. The mean interval between operations was 129 months. Every patient was completely disabled despite treatment with large dosages of prednisone in combination with pyridostigmine (n = 5) or azathioprine (n = 3) and with repeated plasma exchanges.

RESULTS

Gross (n = 5) or microscopic (n = 3) residual thymic tissue was found in all patients. There was no mortality, but morbidity included 2 patients with postoperative myasthenic crisis requiring reintubation and mechanical ventilation. The mean hospital stay was 4.75 days. The mean follow-up was 28.3 months. At the last follow-up, 6 patients had achieved symptomatic improvement as expressed by significant change in mean Osserman class (3.37 versus 2.12, p = 0.03), and prednisone dosage (43 versus 20 mg/d, p = 0.03). Conversely, there was no difference in dosage of pyridostigmine and azathioprine or in number of exchange cycles.

CONCLUSIONS

Our results suggest that thoracoscopic completion thymectomy may be beneficial for selected patients with refractory nonthymomatous myasthenia.

Thoracoscopic thymectomy in autoimmune myasthesia: results of left-sided approach

BACKGROUND

We undertook to analyze the results of video-assisted thoracoscopic thymectomy through a left-sided approach in patients with autoimmune myasthenia.

METHODS

Between 1993 and 1997, 31 patients underwent thoracoscopic thymectomy by a uniform left-sided approach. There were 8 men and 23 women with a mean age of 34 +/- 12 years.

RESULTS

Preoperative duration of disease was 14.8 +/- 11 months. There were no operative deaths or major complications. The mean hospital stay was 5.2 +/- 2.8 days. Mean follow-up was 39.6 +/- 15 months and was 100% complete. At 48 months, remission and improvement rates were 36% and 96%, respectively. Shorter duration of symptoms (< 12 months) correlated with improved outcome (13 of 13 patients versus 10 of 14 patients; p = 0.036). Age, sex, Osserman class, corticosteroid therapy, presence of ectopic thymic tissue, and temporary postoperative symptom increase (deterioration) did not affect outcome.

CONCLUSIONS

Thoracoscopic thymectomy facilitated the goal of early thymectomy. Through a left-sided approach, improvement or remission was achieved in more than 95% of the patients. Thoracoscopic thymectomy should be considered a valid less invasive alternative to the most radical open approaches.