"Maximal" thymectomy for myasthenia gravis. Results

Thymectomy has been shown to be effective in the treatment of myasthenia gravis. The logical goal of operation has been complete removal of the thymus, but there has been controversy about the surgical technique and its relation to results. Surgical-anatomic studies have shown gross and microscopic thymus widely distributed in the neck and mediastinum. We believe that an en bloc transcervical-transsternal "maximal" thymectomy is required to remove all thymic tissue predictably. Ninety-five patients with generalized myasthenia gravis underwent "maximal" thymectomy consecutively between 1977 and 1985 and were evaluated 6 months to 89 months after operation. In Group A (N = 72), myasthenia gravis without thymoma, the uncorrected data revealed that 96% (69) had benefited from operation: 79% (57) had no symptoms; 46% (33) were in remission; 33% (24) were symptom free when receiving minimal doses of pyridostigmine; and none were worse. Life table analysis yielded a remission rate of 81% at 89 months. In group B (N = 8), myasthenia gravis without thymoma for which patients underwent reexploration for incapacitating weakness after earlier transcervical or transsternal operations, residual thymus was found in all. One patient was in remission, two were symptom free when receiving medication, one was unchanged, and none were worse. In group C (N 15), myasthenia gravis and thymoma, two patients were in remission and nine were symptom free when receiving medication. Two patients in this group died 2 and 4 years postoperatively in crisis. Response to thymectomy in group A was greater in patients with mild myasthenia gravis and may have been better in patients who had symptoms for less than 60 months preoperatively, but the response did not depend on age, sex, presence or absence of thymic hyperplasia or involution, or titers of acetylcholine receptor antibodies. The response to thymectomy in group B was striking but slower than in group A, perhaps because symptoms were more severe and of longer duration. The response in group C was also less good than in group A and proportionately fewer benefited. These results support the recommendation for thymectomy in the treatment of patients with generalized myasthenia gravis and indicate the desirability of a maximal procedure. For persistent or recurrent severe symptoms after previous transcervical or submaximal transsternal resections, reoperation by this technique is also recommended.     

Thymoma is associated with relapse of symptoms after transsternal thymectomy for myasthenia gravis

Thymectomy is considered a therapeutic option for patients with myasthenia gravis. A myasthenic patient who has not received any treatment for years and shows no signs or symptoms of the disease after operation is still susceptible to a recurrence of myasthenic symptoms. To investigate which factors are related to relapse of symptoms in patients having thymectomy, we conduct a retrospective review in the patients who had experienced complete remission after thymectomy. Complete remission was achieved in 92 of 154 patients who received extended transsternal thymectomy for myasthenia gravis. Among these 92 patients, 20 patients had relapse of symptoms and needed medication again after complete remission was achieved (21.7%). Ten of 22 patients in the thymomatous group had relapse of symptom after complete remission was achieved, while only 10 of 70 patients in the nonthymomatous group had relapse of symptom (P=0.006). Multivariate Cox regression analysis revealed that thymoma was an independent factor for the development of relapse of symptoms. In conclusion, thymoma is an adverse prognostic factor for the MG patients who have experienced complete remission after thymectomy. The patients with thymoma had a greater possibility to develop relapse of symptoms than the patients without thymoma.     

Effects of thymectomy in myasthenia gravis.

Factors influencing onset of remission in myasthenia gravis were evaluated in 2062 patients, of whom 962 had had thymectomy. Multivariate analysis showed that appearance of early remissions among all patients was significantly and independently influenced by thymectomy, by milder disease, and by absence of coexisting thymomas. Patients with mild generalized symptoms treated with thymectomy reached remission more frequently, even when compared with those with ocular myasthenia treated without surgery. Short duration of disease before thymectomy in mild cases was another factor associated with earlier remissions. Mortality for all patients was significantly and independently influenced by severity of symptoms, age, associated thymomas, and failure to remove the thymus. Patients without thymectomy and with thymomas had, in addition, earlier onset of extrathymic neoplasms. Morbidity after the transcervical approach was minimal. This study demonstrates that early thymectomy by the transcervical approach, when technically feasible, has significant clinical advantages over the transthoracic approach and should be advocated for all patients with myasthenia gravis, including those with ocular disease.     

Video-assisted transcervical thymectomy

Background The optimal surgical approach for complete removal of the thymus gland has long been debated. In this report, the excision of the entire gland through a transcervical incision using video-assisted techniques is described.Methods Ten patients, including one with thymoma and myasthenia gravis, underwent surgery via the transcervical approach. After standard dissection up to the level of the innominate vein and ligation of the thymic vessels, a laparoscope was inserted into the mediastinum. In the patient with thymoma, the operation was completed by a small incision in the third intercostal space.Results No perioperative mortality or long-term morbitity was observed. The mean hospital stay was 69.6 h. After a mean follow-up period of 63.8 months, eight patients displayed complete remission, whereas one continued to receive minimal medication. The patient with thymoma showed considerable improvement, but remained on same medical regimen No complications were seen throughout the study.Conclusion Video-assisted thymectomy improves effectiveness of the transcervical approach for thymectomy with a minimum of trauma and excellent results.     

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.     

横断胸骨扩大胸腺切除治疗全身型重症肌无力

目的探讨经横断胸骨入路行扩大胸腺切除治疗重症肌无力的临床疗效。了解该入路的特点及临床疗效有助于该领域胸外科医师在临床实践中进行更好的临床决策。 方法对1998至2008年在复旦大学附属华山医院胸心外科行横断胸骨治疗全身型重症肌无力的211例患者的临床资料进行回顾性研究,分析患者术中和术后基本情况。并对术后5年进行随访的患者根据是否合并胸腺瘤进行分组,采用χ²检验比较两组间的疗效。 结果经横断胸骨入路能满足对合并Masaoka-Koga Ⅰ期及Ⅱ期胸腺瘤患者及无瘤患者实施扩大胸腺切除的需要,手术并发症较低,便于围术期护理,恢复迅速。对173例患者进行术后5年随访,总缓解率达到79.8%(138/173),无肿瘤复发。合并胸腺瘤组的总缓解率为81.9%(59/72),未合并胸腺瘤组的总缓解率为78.2%(79/101),两组间比较差异无统计学意义(χ²＝0.362,P＝0.548)。 结论与其他常用手术入路相比,横断胸骨入路的特点值得该领域胸外科医师关注。     

Surgical outcome of thymectomy for myasthenia gravis

Background The medical treatment for myasthenia gravis has been reported to have remission rates as low as 15%. Thymectomy on the other hand has been reported to have clinical remission rates up to 80% and therefore has become the accepted mode of treatment. Methods 57 patients diagnosed with myasthenia gravis underwent thymectomy at the Christian Medical College and Hospital, Vellore from January 1994 to December 2003. The aim of this study was to determine the outcome for myasthenia gravis after thymectomy. Results Our results indicated that female sex had a better over all prognosis, Ossermann stage, I, IIA, & III was associated with higher incidence of complete clinical remission and the response to thymectomy decreased with increasing Ossermann stage. Post operative medication requirement reduced significantly as compared to the preoperative requirement. Conclusion We therefore conclude that trans-sternal thymectomy was found to be beneficial to all patients of mild to moderate myasthenia gravis, with 70.2% patients showing improvement postoperatively. We also advocate thymectomy for ocular myasthenia gravis.     

Thymoma following transcervical thymectomy for myasthenia gravis

A superior mediastinal thymoma was found in a patient two years following a transcervical thymectomy for myasthenia gravis. This case report illustrates another potential complication of incomplete thymectomy that may occur with the transcervical approach.     

Long-Term Clinical Outcome After Transcervical Thymectomy for Myasthenia Gravis

Background. We reviewed the long-term clinical outcome after transcervical thymectomy for generalized myasthenia gravis without thymoma in 52 patients who had this procedure at The Toronto Hospital between 1977 and 1986, and compared the results with those reported after more radical surgical approaches.

Methods. Preoperative and postoperative patient evaluations were based on a modified Osserman classification. We defined complete remission as asymptomatic with normal strength and without medications for myasthenia gravis. The complete remission rate was selected as the best measure for comparison between different surgical approaches.

Results. The 52 patients were followed up for a mean of 8.4 years (±6.1 years [standard deviation]). The preoperative mean Osserman grade was 2.7 compared with 0.4 at final follow-up. Complete remission occurred in 44.2% of patients. Similar results are reported after transsternal thymectomy.

Conclusions. Comparable results after transcervical and transsternal thymectomy favor the use of the less radical approach.     

Trans-sternal thymectomy in myasthenia gravis

Between 1986 and 1989 27 patients with myasthenia gravis underwent radical thymectomy: 24 patients without and two patients with thymoma through a trans-sternal incision, another with thymomatous myasthenia through a left-sided thoracotomy. The patients were staged according to the modified Ossermann classification. The results were evaluated prospectively according to the Disability Status Scale of Oosterhuis. During a mean follow up of 22.4 months, 21 patients (77%) benefited from the operation with complete remission achieved in 9 (33%) and significant improvement noted in 12 (44%). There were no operative deaths and no hospital morbidity. The mean operation time was 88 minutes, the mean postoperative hospital stay 10.5 days. These results support the recommendation for radical trans-sternal thymectomy in the treatment of patients with myasthenia gravis as a safe procedure.     

Subxiphoid thoracoscopic thymectomy for myasthenia gravis

We investigated the efficacy of subxiphoid thoracoscopic thymectomy in patients with myasthenia gravis. The data of 37 consecutive cases were reviewed. 2 cases of postoperative myasthenia gravis crisis and 4 cases of residual mediastinal fat tissue were recorded. Moreover, 29 patients presented the neurological outcomes, and complete stable remission was achieved in 5 (17.2%) cases. Subxiphoid thymectomy is technically feasible. High-quality evidence is warranted before this approach can be recommended.     

Prognosis in occult thymomas in myasthenia gravis following transcervical thymectomy

Thymomas were noted in 239 (11%) of 2097 myasthenic patients followed up at our institution. Among 996 patients who had undergone thymectomy, 191 patients (19%) had thymomas compared with 48 (4%) of 1101 patients treated without surgery. A definitive diagnosis of thymoma was not made until after thymectomy in 61 patients (35%); in patients not treated with thymectomy, 23% of associated tumors were diagnosed at autopsy. Patients with occult thymomas treated with the transcervical approach had a clinical course superior to those with tumors diagnosed prior to surgery and treated with the transsternal approach. Most of the advantage could be attributed to the association of occult thymomas with small tumor size and to the association of the latter with absence of invasiveness. Small tumor size was significantly associated with higher remission and lower mortality as shown in a proportional hazards analysis. Occult thymomas were accessible through the transcervical approach, with some operations necessitating a complementary mediastinotomy. Thymectomy, through the transcervical approach if technically feasible, is of benefit to all patients, has minimal morbidity, and should be performed early in the course of the disease as a diagnostic and therapeutic intervention since the risk of occult thymomas in patients with myasthenia gravis is high.     

Impact of minimally invasive trans-cervical thymectomy on outcome in patients with myasthenia gravis.

OBJECTIVE: To study the impact of minimally invasive trans-cervical thymectomy on the incidence of remission of patients with myasthenia gravis (MG) in a single institution over a 10-year period. METHODS: A total of 120 consecutive patients referred for video-assisted trans-cervical thymectomy between 1991 and 2000 were included in the analysis. Complete remission was defined as no symptoms and no treatment for 6 months, and remission as minimal ocular symptoms (slight ptosis) or treatment with pyridostigmine only for 6 months. RESULTS: There were 86 females and 34 males with a median age of 33 (range 14-79) and 36 years (range 12-68), respectively. Symptoms of MG lasted between 2 months and 17 years before thymectomy (median 10 months). Surgery was converted to a partial upper sternotomy in 23 cases (19%). The median hospital stay decreased from 2 days (range 1-8) before 1994 to 1 day (range 1-8) thereafter (p<0.0001). Postoperative complications occurred in four patients (3.3%). After a median follow-up of 48 months (range 6-117 months), 50% of the patients were in complete remission (41%) or in remission (9%). Kaplan-Meier estimates rate of complete remission were 30% after 5 years of follow-up and 91% after 10 years. CONCLUSIONS: Minimally invasive trans-cervical thymectomy can be performed with short hospital stay and low morbidity, and achieve excellent durable results at 10 years.     

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.     

Appearance of thymoma 15 years after extended thymectomy for myasthenia gravis without thymoma.

Several cases of thymoma recurrence after resection have been reported. However, thymoma appearance following an extended thymectomy for non-thymomatous myasthenia gravis is very rare. We report a case of thymoma in a 48-year-old woman, 15 years after an extended thymectomy for non-thymomatous myasthenia gravis. The importance of a complete dissection of mediastinal adipose tissue during the extended thymectomy as well as careful follow-up for such patients is also noted.     

Results and problems of thymectomy in myasthenia gravis over 65 years old

From June 1975 to March 1999, 300 cases of myasthenia gravis (MG) have undergone thymectomy. Twenty-eight patients over 65 years old were examined, focusing on the relationship between clinical appearances and microscopic findings of the thymuses. Among these cases, six were classified as ocular type (one case with thymoma) and 22 generalized type (eight cases with thymoma). According to the thymoma registering stages defined by Masaoka and colleagues, those nine cases with thymoma associated with stages I (n = 7), II (n = 1) and III (n = 1), respectively. The case of stage III (74 year old female) died four years and eight months after surgery. The case of stage II died of old age two years after the surgery. Complete remission was achieved in two cases of stage I. The follicular hyperplasia were seen in eight cases, and all resulted in improvement. Nine cases with no particular findings of thymuses classified into four ocular type and five generalized type including one fulminating type. Post-operative course of all these cases were uneventful. Although one recurrent of the thymoma and one death of the tumor were observed, post-operative outcomes of these elderly patients were generally satisfactory. We concluded that there is an operative indication of thymectomy for MG of even elderly patients, if no particular findings were recognized in the thymus.     

The result of extended thymectomy in patients with myasthenia gravis of pure ocular type

We studied postoperative status of 14 patients with myasthenia gravis of ocular type who underwent extended thymectomy. Nine patients were in remission, three improved, and two unchanged. No patient became worse and died. The remission rates at one, three, five, and ten years after operation were 50.0%, 58.3%, 60.0%, and 80.0%. The palliation rates at one, three, five, and ten years after operation were 64.3%, 75.0%, 80.0%, and 100%. The remission rate at one year after operation in patients of ocular type was significantly (p less than 0.05) higher than that in generalized type (191 patients). The mean preoperative duration of symptoms in patients who obtained remission after surgery was 7.2 +/- 6.5 months, while mean duration was 85.6 +/- 45.8 months in those patients who could not obtain remission, indicating a significant difference (p less than 0.05) of duration of symptoms between two groups. Among 89 patients with generalized as well as ocular symptoms before extended thymectomy, 62 patients (69.7%) still complained of ocular symptoms and 48 patients (53.9%) had generalized symptoms with or without ocular symptoms in 1 to 12 years after operation. This result shows that ocular symptoms do not disappear more easily than generalized ones. We conclude that extended thymectomy should be performed even in patients with myasthenia gravis of pure ocular type.     

Prognostic significance of thymomas in patients with myasthenia gravis

BACKGROUND: The presence of thymoma may be a negative prognostic factor with respect to the outcome of myasthenia gravis (MG). METHODS: Of 122 consecutive patients with MG undergoing thymectomy between August 1994 and September 2000, 37 had a thymoma. Postoperative radiation was administered to all patients with stage II thymoma and higher. To determine differences in presentation and outcome, thymoma patients were compared with patients with atrophic (n = 49) or hyperplastic (n = 36) thymus gland on final pathology. RESULTS: Thymoma patients were significantly older (52 +/- 14 vs 36 +/- 15 years, p < 0.0001) and included a significantly higher proportion of males (54% vs 28%, p = 0.006) than patients without thymoma. However, the preoperative Osserman grade and the duration of symptoms before surgery were not significantly different between groups. Mean follow-up after thymectomy was not significantly different between patients with or without thymoma (32 +/- 23 vs 37 +/- 19 months, respectively, p = 0.3). At last follow-up, the proportion of asymptomatic patients (63% vs 70%, respectively, p = 0.5) and the mean Osserman grade (0.6 +/- 0.9 vs 0.5 +/- 0.9, respectively, p = 0.6) were similar in both groups. In addition, the rate of complete remission reached 36% at 5 years in patients with or without thymoma (p = 0.8). CONCLUSIONS: Although myasthenic patients with thymoma are significantly older and include a greater proportion of males, the overall outcome, including the rate of complete remission, was similar between patients with or without thymoma. Therefore, the presence of a thymoma should not necessarily be viewed as a negative prognostic factor regarding recovery from myasthenia gravis.     

胸骨部分劈开切口行扩大的胸腺切除术治疗重症肌无力

目的介绍胸骨部分劈开切口行扩大的胸腺切除术治疗重症肌无力的手术方法和效果。方法2000年1月至2005年12月,采用胸骨正中部分劈开切口,对32例重症肌无力患者进行了扩大的胸腺切除手术。结果6例肌无力症状完全缓解,19例症状显著改善,5例症状轻微改善,而仅有2例手术后症状完全没有好转。结论胸骨部分劈开切口是实施扩大的胸腺切除治疗重症肌无力的一种安全、有效的手术径路,并且对患者的创伤小,避免了手术后并发症,特别是肌无力危象的发生。     

Experience with programmed steroid treatment with thymectomy in nonthymomatous myasthenia gravis

BACKGROUND: The benefit of thymectomy in myasthenia gravis management is recognized but the perioperative course can fluctuate. The goal of this study was to assess the feasibility and clinical benefit of dose-escalated steroid therapy with thymectomy for nonthymomatous myasthenia gravis. METHODS: We reviewed the records of 69 myasthenia gravis patients who were followed up after undergoing transsternal thymectomy with extended anterior mediastinal dissection in our hospital between 1976-2000. Forty-eight patients in the programmed treatment group who had dose-escalated and de-escalated steroid therapy during the perioperative period comprised 17 patients with ocular myasthenia gravis and 31 patients with generalized myasthenia gravis. Clinical benefits and clinical remission, which was diagnosed when the patients were symptom-free without medications for at least 1 year, were compared with those of 21 patients in the occasional treatment group who received medications occasionally over the perioperative period. RESULTS: Postoperative respiratory failure and myasthenic crisis did not occur in the programmed treatment group but did occur in 6 patients in the occasional treatment group. Remission rates in the programmed treatment group (mean follow-up, 6.4 years) were 30% at 3 years, 38% at 5 years, and 46% at 10 years; rates in the occasional treatment group (mean follow-up, 9.6 years) were 25% at 3 years, 25% at 5 years, and 45% at 10 years. CONCLUSIONS: Programmed steroid therapy in patients with nonthymomatous myasthenia gravis is feasible and it provides clinical benefit when fluctuating symptoms occur during the perioperative period.