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Effect of thymectomy on peripheral lymphocyte subsets in myasthenia gravis: selective effect on T-cells in patients with thymic atrophy.

Myasthenia gravis (MG) is an autoimmune disease affecting nicotinic acetylcholine receptors. The clinical improvement that follows thymectomy in some myasthenic patients implicates thymic factors as well in the pathogenesis of MG. We have studied circulating immunoregulatory T cell subsets before and after thymectomy in 11 adult patients with MG. Six patients had thymic hyperplasia and five patients had atrophic thymus at the time of thymectomy. Before thymectomy, patients who subsequently were shown to have an atrophic thymus, had lower lymphocyte counts than either patients later shown to have a hyperplastic thymus (1315 +/- 143 lymphocytes/mm3 vs. 2434 +/- 350 lymphocytes/mm3, p less than 0.01), or age-matched controls (1315 +/- 143 lymphocytes/mm3 vs. 2636 +/- 589 lymphocytes/mm3, p less than 0.02). Moreover, after thymectomy, in MG patients with an atrophic thymus, there was a significant rise in lymphocyte count (from 1315 +/- 143 lymphocytes/mm3 to 2279 +/- 292 lymphocytes/mm3, p less than 0.02) beginning 3 days postthymectomy and persisting for at least 6 weeks thereafter. In comparison, patients with a hyperplastic thymus showed no change in circulating lymphocyte counts (p greater than 0.1). Enumeration of lymphocyte subsets in MG patients with an atrophic thymus demonstrated normal B cell numbers before and after thymectomy (p greater than 0.1), whereas, T cells were significantly decreased before thymectomy compared with age-matched normal subjects (859 +/- 82 T cells/mm3 vs. 2215 +/- 545 T cells/mm3, p less than 0.05), and rose to near normal levels after thymectomy (1796 +/- 294 T cells/mm3, p less than 0.02 compared with prethymectomy levels). Using monoclonal anti-T cell antibodies 3A1, OKT4, and OKT8, we found that, before thymectomy in the atrophic thymus group, 3A 1+ T cells were significantly depressed compared with postthymectomy levels (620 +/- 173 cells/mm3 vs. 1627 +/- 331 cells/mm3, p less than 0.02) as were OKT4+ cells 436 +/- 88 cells/mm3 vs. 1112 +/- 63 cells/mm3, p less than 0.001), In contrast, no significant change was seen after thymectomy in the OKT8+ cell subset (p greater than 0.1). MG patients with an atrophic thymus had decreased plasma cortisol levels postthymectomy compared with prethymectomy levels, whereas thymectomy in MG patients with a hyperplastic thymus effected no change in plasma cortisol levels. These data demonstrate in MG patients with an atrophic thymus that thymectomy has an effect on the number of circulating T cells, and in particular, on those T cells expressing antigens 3A1 and OKT4. This effect may in part be mediated by changes in plasma adrenal corticosteroid levels after thymectomy or may be due to a factor produced by atrophic thymuses in MG.

Antigens, Differentiation, T-Lymphocyte↗

Beneficial effects of plasmapheresis before thymectomy on the outcome in myasthenia gravis.

OBJECTIVE: Since 1980, we have performed plasmapheresis before thymectomy for patients with generalized symptoms in order to protect against myasthenic crisis and to improve patient outcomes after thymectomy. The aim of this study was to evaluate an immediate and a long-term results of plasmapheresis before thymectomy for myasthenia gravis, retrospectively. METHODS: Between January 1980 and December 1997, 51 patients with Osserman class IIA or IIB symptoms were treated with transsternal thymectomy. Nineteen patients (group 1) were treated with plasmapheresis before thymectomy and 32 patients (group 2) were treated with thymectomy alone. RESULTS: In group 1, the time of plasmapheresis prior to thymectomy was 3.2 +/- 1.5. Nine (28.1%) patients in group 2 had crisis within 1 year after thymectomy as compared with only one (5.3%) patient in group 1 had crisis (p = 0.049). There was no evidence of crisis within 30 days after thymectomy in group 1 and 5 (15.6%) patients in group 2 (p = 0.0724). There was no postoperative death among patients in group 1. Responses to thymectomy in group 1 improved significantly, the improvement and pharmacologic remission rate had increased up to 100% and 79% at 5-7 years after operation, while the improvement and pharmacologic remission rate of group 2 had increased to 81.3% (p = 0.0466 vs. group 1) and 50.0% at that time (p = 0.0427 vs. group 1). CONCLUSIONS: The present study demonstrated that preoperative plasmapheresis may facilitate improved outcomes of patients with myasthenia gravis after thymectomy.

Adolescent↗

Extended trans-sternal thymectomy for myasthenia gravis.

Otto reported thymectomy under transverse sternotomy. It currently is not a widely used procedure, however. Jaretzki graded the completeness of removal of thymic tissue as follows: maximal thymectomy 98% to 100%, extended thymectomy 85% to 95%, modified transcervical thymectomy (Cooper) 75% to 80%, VATS thymectomy 80% to 85%, simple trans-sternal thymectomy 70% to 75%, and simple transcervical thymectomy 40% to 50%. The results of each procedure do not always reflect the completeness of removal. The tables show that the most widely accepted procedure is the extended thymectomy, and the results of it are prominent and stable. Why do the results of the maximal thymectomy, however, not exceed those of the extended thymectomy? It is supposed that quantitative increase of removed thymic tissues in the maximal thymectomy might be minimal.

Humans↗

Long-term outcome and factors influencing the outcome of thymectomy for myasthenia gravis.

Thymectomy has gained widespread acceptance as a treatment for patients with myasthenia gravis (MG). Patients with myasthenia gravis who had undergone thymectomy by extended transsternal approach between 1981 and 1987 were retrospectively reviewed to evaluate the result of thymectomy, time to remission, time to maximum improvement and factors influencing remission after thymectomy. There were 128 patients, 45 men and 83 women and the mean ages at the time of thymectomy were 35.7 and 32.2 years respectively. After thymectomy, 41.2% of the patients were in remission, 53% improved and 5.8% had no response. The remission rates at 1, 2, 5 and 10 years after thymectomy were 9%, 17%, 37% and 53% respectively and the median time to remission was 9 years. The maximum improvement rates at 1, 2, 5 and 10 years after thymectomy were estimated to be 30%, 40%, 57% and 78% respectively and the median time to maximum improvement was 3.6 years. Patients with ocular MG, longer duration of symptoms before thymectomy and atrophic thymus gland appeared to take longer to achieve remission although none of the factors was significantly associated with the time to remission. Thymectomy is beneficialfor MG patients with satisfactory remission and improvement rates. It is recommended that thymectomy should be advocatedfor these patients early in the course of the disease because the duration of the symptoms appeared to be the main determinant of the outcome.

Adult↗

Effect of thymectomy on human peripheral blood T cell pools in myasthenia gravis.

The human thymus is required for establishment of the T cell pool in fetal life, but postnatal thymectomy does not lead to immunodeficiency in humans. Because thymectomy in humans is performed for treatment of myasthenia gravis (MG), we have studied patients with MG for effects of thymectomy on peripheral blood (PB) naive (CD45RA(+), CD62L(+)) and memory (CD45RO(+)) T cells. We have also determined the effect of thymectomy on levels of PB cells containing signal joint TCR delta excision circles (TRECs), a molecular marker of thymus emigrants that have divided few times after leaving the thymus. In 17 nonthymectomized and 26 thymectomized MG patients studied at varying times after thymectomy (1 day to 41 years), we found no significant mean difference in PB T cell TREC levels between ages 40 and 80 years. However, both thymectomized and nonthymectomized MG patients had lower PB T cell TREC levels than did age-matched normal subjects (p < 0.0001 for both). These data demonstrated that MG itself or treatment for MG decreased thymopoiesis independent of thymectomy. Next, to control for disease activity and treatment, we prospectively studied 10 MG patients before and from 27 to 517 days after thymectomy. We found that thymectomy decreased CD4 or CD8 T cell TREC concentrations most when thymopoiesis was active before thymectomy (six of six patients), but had little effect in patients when thymopoiesis was minimal (four of four patients). In contrast, there was no significant effect of thymectomy on absolute numbers of naive PB T cells. Thus, in MG, removal of a thymus with active thymopoiesis resulted in a significant fall in PB TREC(+) T cells postthymectomy.

Adolescent↗

Studies in myasthenia gravis: early thymectomy. Electrophysiologic and pathologic correlations.

Indications for thymectomy in myasthenia gravis have been recently expanded to include all cases with extraocular symptoms as a result of the minimal morbidity and negligible mortality of the transcervical approach. As increasing numbers of patients with myasthenia gravis, covering the entire spectrum of generalized disease, have been added to the thymectomy population, a more accurate evaluation of the effects of the operation is possible. Our experience with 353 patients who have undergone thymectomy indicates that early thymectomy, particularly in patients who do not have germinal centers, is followed by early remission of the disease. Delayed remission after thymectomy is related to the duration and severity of the disease, and to presence of thymic germinal centers. Germinal centers were found more frequently in patients with long duration of the disease and in patients in whom the disease had progressed to respiratory involvement. Marked improvement in electromyographic findings immediately after thymectomy was observed in the majority of patients who had had the disease for 1 year of less and where germinal centers were absent. The percentage of malignant thymomas was higher in patients who underwent thymectomy 1 year or more after the onset of symptoms of myasthenia gravis. These data indicate the importance of early thymectomy while the disease is still in the mild stages. Transcervical thymectomy is the treatment of choice as it is followed by a higher percentage of remissions and by less morbidity than other forms of treatment.

Adolescent↗

Comparison of late results of basic transsternal and extended transsternal thymectomies in the treatment of myasthenia gravis.

BACKGROUND: The influence of the technique of thymectomy on late results in the treatment of myasthenia gravis remains controversial. METHODS: Results of 60 basic transsternal thymectomies and 58 extended transsternal thymectomies were compared. Both positive results (complete remissions or improvement) and negative results (no improvement, deterioration, or death from myasthenia) were analyzed. RESULTS: There were no differences between both groups according to patient's characteristics and postoperative complications rate. Ectopic foci of the thymic tissue were discovered in the fat of the neck and the mediastinum in 56.9% of patients from the extended thymectomy group. The foci occurred in all areas of dissection of the neck and the mediastinum. Complete remission rates in the basic thymectomy group were 8.3%, 11.7%, 15.0%, 16.7%, 20.0%, and 21.7% after 1, 2, 3, 4, 5, and 6 years of follow-up, respectively, and 29.3%, 37.9%, 41.4%. and 46.6% after 1, 2, 3, and 4 years, respectively, in the extended thymectomy group. The differences between both groups after 1, 2, 3, and 4 years were statistically significant (p = 0.0093, p = 0.0013, p = 0.0018, and p = 0.0007, respectively). Negative results were noted in 23.3% of patients in the basic thymectomy group and in 6.9% of patients in the extended thymectomy group (p = 0.0613). No other factors had any influence on the results. CONCLUSIONS: Late results, both positive and negative, were considerably better in the extended thymectomy group. The difference can be explained by the removal of ectopic foci of the thymic tissue from the neck and the mediastinum in these patients.

Adipose Tissue↗

Thymectomy in the treatment of ocular myasthenia gravis.

BACKGROUND: Thymectomy is an effective and accepted treatment for myasthenia gravis, but thymectomy for ocular myasthenia gravis (Osserman stage I) is controversial. OBJECTIVE: To assess the efficacy and propriety of thymectomy for the treatment of ocular myasthenia gravis. METHODS: We conducted a review and follow-up of all patients who had thymectomy for the treatment of ocular myasthenia gravis between 1970 and 1998 at the University of California, Davis, Medical Center, and the University of Rome, "La Sapienza," Rome, Italy. Patient response to thymectomy was categorized as follows: cured, patients who became symptom-free and required no further medication; improved, patients who required less medication and whose symptoms were less severe; unchanged, patients whose symptoms and medications were the same; worse, patients who had more severe symptoms, needed more medication, or died. RESULTS: Sixty-one patients (mean age 37 years; range 14-73 years) were followed up for a mean duration of 9 years (range 0.5-29 years). Ocular myasthenia gravis with mixed and cortical thymomas, stages I to IV, occurred in 12 patients, and ocular myasthenia without thymomas occurred in 49 patients. Transsternal thymectomy (n = 55) and transcervical thymectomy (n = 6) resulted in cure in 31 (51%) patients, improvement in 12 (20%) patients, no change in 16 (26%) patients, and worsening of symptoms (including 1 postoperative death) in 2 patients. Patient outcomes were statistically independent of the duration of preoperative symptoms (mean 9.5 months), patient age, or the presence or absence of thymoma. In patients with ocular myasthenia, 70% were cured or improved after thymectomy; in the subgroup of patients with ocular myasthenia and thymoma, 67% were cured or improved. CONCLUSION: Thymectomy is an effective and safe treatment for patients with ocular myasthenia gravis.

Adolescent↗

Prognostic factors of thymectomy in patients with myasthenia gravis: a cohort of 132 patients.

OBJECTIVE: To identify the response to thymectomy and the factors associated with a poor response, a nested case-control study was performed on 132 patients with an established diagnosis of myasthenia gravis who had had a thymectomy between 1987 and 1997 and had been followed up for at least 3 years. METHODS: In order to assess the response to thymectomy, the following two points were taken into account: (a) the dose of pyridostigmine and other drugs (steroids, azathioprine) that the patient took before and after thymectomy, and (b) the Osserman classification before and after thymectomy. The patients were divided into 4 groups: (1) patients in remission; (2) patients with improvement; (3) patients with no change, and (4) patients who were worse. RESULTS: 91 patients had a good response (69%) and 41 patients had a poor response (31%). The response by groups was as follows: 50 patients were found to be in remission; 41 patients had improved; 34 patients had no changes, and 7 got worse. Being more than 60 years old was associated with a poor prognosis (odds ratio 4.6, CI 1.11-20.32, p 0.01). The patients who had the disease for more than 3 years (odds ratio 2.97, CI 0.79-5.39, p 0.09) had a tendency towards a bad prognosis even though there was no statistical significance, and for those who had it for more than 4 years (odds ratio 2.58, CI 0.89-0.96, p 0.02) the bad prognosis was statistically significant. The patients who had the disease for more than 3 years between diagnosis and thymectomy (odds ratio 2.02, CI 0.69-5.90, p 0.15) and those with it for more than 4 years (odds ratio 2.53, CI 0.83-7.7, p 0.06) had a tendency towards a poor prognosis even though there was no statistical significance. In addition, having Osserman I was associated with a bad prognosis. Referring to the pathological findings, patients with thymoma (odds ratio 3.51, CI 0.43-31.5, p 0.15) and those with thymic atrophy (odds ratio 2.19, CI 0.93-5.16, p 0.04) had a poor prognosis. Finally, the use of steroids before thymectomy (odds ratio 2.26, CI 0.99-5.18, p 0.03) was associated with a worse prognosis. CONCLUSIONS: The response to thymectomy was high (69%). The variables that had the most prognostic importance were age and the Osserman stage. Other variables of poor prognosis were: high doses of pyridostigmine and use of steroids before surgery; the total duration of the disease and the duration of the disease between diagnosis and the surgical procedure; history of previous thymectomy; use of plasmapheresis after surgery, and the discovery of thymic atrophy and thymoma in the histopathological result.

Adrenal Cortex Hormones↗

Role of video-assisted thoracic surgery for the treatment of myasthenia gravis: extended thymectomy by median sternotomy versus the thoracoscopic approach with sternal lifting.

The role of video-assisted thoracic surgery (VATS) thymectomy is still being studied, and many surgeons remain skeptical of the value of this recent option. We made a retrospective evaluation to ascertain whether VATS-extended thymectomy is as reliable as standard median sternotomy in the treatment of myasthenia gravis (MG) and whether the endoscopic procedure presents any advantages for patients. Eighteen consecutive patients requiring extended thymectomy for MG were treated between April 1997 and September 2003 at our hospital. Nine patients received VATS-extended thymectomy, and the remaining nine patients received standard extended thymectomy by sternotomy. In the VATS group, the anterior mediastinal space was well visualized by sternal lifting. The mean operative time was 268.3 +/- 51.1 minutes in the VATS group and 177.3 +/- 92.5 minutes in the sternotomy group. Operative time was significant longer in the VATS group than in the sternotomy group (P < 0.05). The mean operative bleeding was 68.6 +/- 47.8 ml in the VATS group and 154.1 +/- 109.0 ml in the sternotomy group. Operative bleeding was significantly less in the VATS group than in the sternotomy group (P < 0.05). There was no significant difference between the two groups with regard to postoperative duration of chest tube or the level of serum C-reactive protein on the first operative day. There was a downward trend in nicotinic acetylcholine receptors antibody levels after thymectomy compared with before thymectomy in both groups. VATS thymectomy should be considered a valid alternative to the established approaches aimed at achieving a "curative thymectomy" in patients with MG.

Adolescent↗

Thymectomy for myasthenia gravis.

OBJECTIVES: To assess the change in clinical status of patients with generalized myasthenia gravis treated with thymectomy and to identify prognostic variables that may be of significance in optimizing patient selection. DESIGN: Retrospective review. Mean follow-up period was 41 months. SETTING: Large community hospital. PATIENTS: Thirty-seven patients (11 male and 26 female) with generalized myasthenia gravis who were referred for thymectomy if they were refractory to medical treatment or had a thymoma. This represents all patients undergoing thymectomy for myasthenia gravis between January 1982 and December 1991. INTERVENTIONS: Each patient underwent staging before and after thymectomy using a modified Osserman classification. Medication requirements were also recorded. All patients underwent transsternal thymectomy and complete mediastinal dissection. MAIN OUTCOME MEASURES: Changes in clinical stage and medication requirement before and after thymectomy; effect of patient age, sex, duration of disease, stage of disease, antibody status, histologic characteristics of the thymus, and duration of follow-up on outcome. RESULTS: Improvement after thymectomy was noted in all 37 patients. Complete remission was achieved in three patients (8%) and pharmacologic remission in 23 (62%). The remainder improved in stage, medication requirement, or both. Patients in preoperative stages IIb and IIc showed the greatest improvement. Age, sex, duration of disease, antibody status, histologic characteristics of the thymus, and duration of follow-up were not significant factors in assessing improvement. CONCLUSIONS: Transsternal thymectomy was found to be beneficial to all patients with generalized myasthenia gravis. Complete or pharmacologic remission was achieved in most patients (70%) following the procedure. Patients in preoperative stages IIb and IIc showed the greatest degree of postoperative improvement.

Adolescent↗

Operative technique for thoracoscopic thymectomy.

In most cases, myasthenia gravis (MG) and thymoma require complete removal of the thymus gland and resection of the pericardial fatty tissue. There is some debate however, over which surgical approach is best for thymectomy. We have developed a new technique for complete thoracoscopic thymectomy. Between October 1994 and February 1998, we performed a prospective observational study of thoracoscopic thymectomy in 19 patients. The results were analyzed with special reference to perioperative morbidity, short- and intermediate-term improvement of MG, and quality of life. This study showed the feasibility of complete thoracoscopic thymectomy. The procedure was successfully applied in 19 of 20 cases. Thoracoscopic thymectomy was accomplished with zero mortality and a very low perioperative morbidity. While the short-term improvement of MG after this procedure was comparable to that seen with conventional surgery, the short- and intermediate-term quality of life was much better. The preliminary results of thoracoscopic thymectomy appear to be excellent for both patients and neurologists. A prospective randomized trial has been designed to compare thoracoscopic thymectomy with the gold standard of median sternotomy for thymectomy.

Adult↗

The immunologic role of thymectomy in the treatment of myasthenia gravis: implication of thymus-associated B-lymphocyte subset in reduction of the anti-acetylcholine receptor antibody titer.

BACKGROUND AND PURPOSE: Thymectomy is generally accepted as the major option of treatment for myasthenia gravis. To elucidate the biological role of thymectomy in the treatment of myasthenia gravis, the immunologic characteristics of the thymus was studied in association with the postoperative kinetics of the anti-acetylcholine receptor antibody titer. MATERIALS AND METHODS: Thirty-four patients with nonthymomatous myasthenia gravis who had positive anti-acetylcholine receptor antibody titer and undergoing extended thymectomy were subjected to the study. Reduction of anti-acetylcholine receptor antibody titer was evaluated in terms of the proportion of anti-acetylcholine receptor antibody titer at 1 year after thymectomy to that before the operation. The numbers of B lymphocytes (CD19(+) cells) and the germinal center B lymphocytes (CD19(+)CD38(high) cells) present in 1 g of the thymic tissue were calculated by flow cytometry. RESULTS: The proportion of anti-acetylcholine receptor antibody titer at 1 year after thymectomy ranged from 27.5% to 150%. The numbers of B lymphocytes and the germinal center B lymphocytes in 1 g of the thymic tissue ranged from 0.19 x 10(6)/g to 162.8 x 10(6)/g and from 0.09 x 10(6)/g to 33.4 x 10(6)/g, respectively. The proportion of anti-acetylcholine receptor antibody titer at 1 year after thymectomy had a significant inverted correlation with the number of B lymphocytes (P =.002) as well as that of the germinal center B lymphocytes (P =.007). CONCLUSION: Effectiveness of thymectomy was dependent on predominance of B lymphocytes and the germinal center B lymphocytes in the thymus, suggesting that one of the biological roles of thymectomy in the treatment of myasthenia gravis is removing the thymus-associated germinal centers.

ADP-ribosyl Cyclase↗

Thymectomy for Myasthenia Gravis.

No Class I studies of the effectiveness of thymectomy for myasthenia gravis (MG) have been performed. Most Class II studies comparing outcomes in MG patients with and without thymectomy demonstrated higher MG remission and improvement rates in patients undergoing thymectomy. However, these Class II studies were also consistently confounded by important differences between MG patients in surgical and nonsurgical groups. Myasthenia gravis patients undergoing thymectomy were younger, more often women and were more likely to have severe myasthenia. The authors of this paper cannot determine from these Class II studies whether the observed association between thymectomy and improved MG outcomes was a result of a thymectomy benefit or was merely a result of the multiple differences in baseline characteristics between the surgical and nonsurgical groups. The authors concluded that the benefit of thymectomy in non-thymomatous autoimmune MG has not been conclusively established. Thus, for patients with non-thymomatous autoimmune myasthenia gravis, thymectomy should only be considered an option to increase the probability of remission or improvement. The quality standards subcommittee of the American Academy of Neurology recently adopted this position.

Journal Article↗

[Indications and value of thymectomy in myasthenia gravis].

The therapeutic impact of thymectomy on the clinical course of myasthenia gravis is still a matter of debate. Issues in this discussion that are clinically relevant are reviewed. While the surgical procedure is accepted for thymomas its performance is controversial in cases with no thymomatous tissue. Outcome studies show a weak correlation between clinical course and thymus histology, but there is some doubt about the maximum age for thymectomy and about the therapeutic regimen following surgery. Retrospective studies show that thymectomy has a beneficial influence on the natural course of myasthenia. This positive effect is enhanced by appropriate immunosuppressive therapy together with anticholinesterase inhibitor substitution. Unfortunately, the different forms of myasthenia do not all respond in the same manner. Studies have shown that thymoma-associated myasthenia is more difficult to control than non-thymoma-associated myasthenic states. In both groups some patients go into remission after thymectomy alone, and the majority of patients with the institution of additional immunosuppression. In clinically mild cases thymectomy should not immediately be followed by immunosuppression. This will help to identify those patients responding with remission to thymectomy alone. Mostly these are young women with a hyperplastic thymus. Overall, thymectomy is beneficial and should be considered in all patients with generalized myasthenia who are still under 60 years of age.

Combined Modality Therapy↗

Thymectomy in myasthenia gravis: comparison of outcome in Santiago, Cuba and Nottingham, UK.

OBJECTIVES: We compared the outcome of thymectomy for myasthenia gravis (MG) in two healthcare systems. In Nottingham, UK, thymectomy is performed for thymic enlargement and considered in acetylcholine receptor (AchR) antibody positive patients. In Santiago, Cuba, thymectomy is considered in all generalised MG patients irrespective of their radiological findings or AchR antibodies. METHOD: 22 MG patients in Nottingham and 75 in Santiago who had a thymectomy were identified and their notes reviewed. We compared the median age, stage of disease, thymic histology and clinical outcome at two years post-thymectomy. RESULTS: The median ages for the Cuban and Nottingham patients were 25 and 35 years respectively. The median stage of disease was IIa by Osserman's classification in both. In Nottingham, 59% (13/22) showed an improvement compared with 88 % (66/75) in Santiago (p < 0.01). There were significantly more cases of thymoma in Nottingham whereas thymic hyperplasia and atrophy were a more frequent finding in Cuban patients. The majority of cases who improved post-thymectomy had thymic hyperplasia on histology in both Nottingham (46%) and Cuban (61%) patients. CONCLUSION: Selecting MG patients based on thymic enlargement alone or AchR antibody positivity may be inadequate and thymectomy should perhaps be considered in all patients with generalised myasthenia.

Adult↗

Left thoracoscopic thymectomy in children.

BACKGROUND: In the management of autoimmune myasthenia, thymectomy is recognized as effective surgical therapy. The necessity of complete radical thymectomy to achieve maximal improvement has been emphasized. Video-assisted thoracoscopic surgery has been successfully used for thymectomy in adults, and more recently in children, and has been described as achieving the same radicality and functional improvement as median sternotomy or as transcervical thymectomy. The aim of this work is to report our first thoracoscopic experience in this indication. METHODS: Patients with myasthenia gravis on anticholinesterase drugs and/or steroids are discussed for surgery in case of clinical deterioration despite increasing doses of medication or in case of no improvement. We decided to perform thoracoscopic thymectomies by a left-sided approach. Preoperative localization of thymic tissue is done by a thoracic CT exam. Patients are placed on their right side with a thoracic tilt under the thorax. Four thoracoscopic ports are used, a 10-mm for the camera and three 5-mm operating ports. The left lung was collapsed by selective intubation (double-lumen endotrachial intubation). RESULTS: Two boys, 7.5 and 14 years old, were addressed by the department of neurology for radical thymectomy. They presented an ocular myasthenia gravis for 2 years and a mild general myasthenia gravis for 7 years. The operative times were 120 and 240 min. There was no intraoperative or postoperative complication. Duration of thoracic drainage was 2 days. The children were discharged on the third postoperative day. For the second procedure, an ultrasound exam during surgery was necessary to localize the thymus exactly, thus enabling its complete resection without the need for a conversion. The follow-up is 19 and 7 months with a clinical improvement enabling the diminution of medication for both children, the end of ptosis for the first child, and the general improvement of muscle strength for the second. CONCLUSIONS: Thoracoscopic thymectomy in children with juvenile myasthenia gravis seems to offer a complete surgical resection, as do open techniques. In case of difficulties in finding the thymus, an ultrasound exam is feasible to enable complete resection. The left-sided thoracoscopic approach gives a good mediastinal and cervical exposition. Furthermore, being less painful in the postoperative period, it presents a less pronounced impairment of pulmonary function, and it presents good cosmetic effect.

Adolescent↗

The effect of neonatal thymectomy on the induction of autoimmune orchitis in rats.

The objective of these experiments was to determine the effects of neonatal thymectomy on the induction of experimental autoimmune orchitis in inbred rats of the Fischer 344 and Lewis strains. It was found that thymectomy alone in Lewis rats, and thymectomy followed by immunization with testicular extract in both Lewis and Fischer 344 rats, led to the development of autoimmune orchitis, as indicated by decreased testes weights, increased serum spermagglutinating antibody titers and histopathological changes in the testes. These data indicate that rats of the Lewis strain are genetically predisposed to the development of autoimmune orchitis, and thymectomy alone leads to active manifestations of the disease, which are further enhanced by subsequent immunization with testicular extract. In Fischer 344 rats, thymectomy followed by immunization leads to indications of early signs of experimental autoimmune orchitis. This is in contrast to experimentally induced autoimmune diseases in other model systems, where previous investigators have reported that thymectomy lessens or prevents induction of autoimmune disease. It is suggested that these differences may be related to the timing of thymectomy with regard to differences in the time of appearance of sperm antigens (at puberty) as compared to pre-natal and early neonatal appearances of other autoantigens.

Animals↗