The Role of Thymectomy in the Treatment of Myasthenia Gravis

Perlo, Vincent P.; Arnason, Barry G. W.; Poskanzer, David C.; Castleman, Benjamin; Schwab, Robert S.; Osserman, Kermit E.; Papatestis, Angelo; Alpert, Lawrence; Kark, A E

doi:10.1111/j.1749-6632.1971.tb30761.x

Cited by 85 publications

(22 citation statements)

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“…Relative outcome rates in severe MG patients undergoing thymectomy increased by a median of 54% (p < 0.01) from the relative rate of the entire cohort. For example, in the cohort described by Perlo et al, 29 severe MG patients undergoing thymectomy were approximately 3.7 times more likely to attain remission than severe MG patients not undergoing thymectomy-a 50% increase over the relative remission rate of 2.4 of the entire thymectomy cohort described by Perlo et al 29 The calculated relative outcome rates within the mild 17,20,25,29,32 subgroup was not significantly different from the baseline rates.…”

Section: Figure (A-d) Relative Rate Of Outcomes (With 95% Confidencementioning

confidence: 97%

“…The studies described by Mantegazza et al, 17 Papatestas et al, 20 Rodriguez et al, 25 Perlo et al, 29 and Zeldowicz and Saxton 32 allowed the calculation of relative rates within the severe disease subgroup. Relative outcome rates in severe MG patients undergoing thymectomy increased by a median of 54% (p < 0.01) from the relative rate of the entire cohort.…”

Section: Figure (A-d) Relative Rate Of Outcomes (With 95% Confidencementioning

confidence: 99%

“…12,17,25,26,29,33 Age and gender. The studies described by Rodriguez et al, 25 Buckingham et al, 27 and Simpson 34 allowed us to determine relative outcome rates in the male MG subgroup.…”

Section: Figure (A-d) Relative Rate Of Outcomes (With 95% Confidencementioning

confidence: 99%

“…The majority of the studies reporting the thymectomy technique used the transsternal approach. Subjects in the cohorts described by Beghi et al 15 Mantegazza et al, 17 Papatestas et al, 20 and Perlo et al 29 underwent either transsternal or transcervical thymectomies. Follow-up, when described, varied from an average of 3 to 28 years.…”

mentioning

confidence: 99%

“…Several studies provided sufficient data to recalculate relative rates of outcomes within MG patient subgroups. 12,17,20,21,[25][26][27]29,[32][33][34] Table 4 lists the median change in relative outcome rates within age, gender, and severity subgroups. The positive association between thymectomy and improved outcomes persisted after controlling for each of these variables.…”

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confidence: 99%

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Practice parameter: Thymectomy for autoimmune myasthenia gravis (an evidence-based review) [RETIRED]

2000

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The Quality Standards Subcommittee of the American Academy of Neurology is charged with developing practice parameters for neurologists for diagnostic procedures, treatment modalities, and clinical disorders. The selection of topics for which practice parameters are used is based on prevalence, frequency of use, economic impact, membership involvement, controversy, urgency, external constraints, and resources required. This paper addresses the role of thymectomy in the treatment of nonthymomatous autoimmune MG.In 1939, Blalock et al. 1 reported the remission of generalized MG in a 21-year-old woman after removal of a cystic thymic tumor. Subsequently, Blalock et al.2,3 performed thymectomy on MG patients without thymoma, found hyperplasia in the thymus glands, and reported improvement in at least half of their patients. Since these reports, thymectomy, with or without the presence of thymoma, has gained widespread acceptance as a form of treatment for MG.Because a definitive study of the effectiveness of thymectomy has never been done, 4,5 the role of thymectomy in the management of MG remains uncertain. Nevertheless, physicians have to advise their patients regarding the benefits of thymectomy based on the existing literature. Our goal is to develop evidence-based recommendations for clinicians considering thymectomy for patients with nonthymomatous autoimmune MG by performing a systematic review and analysis of the literature. Process. Identification and selection of studies.We searched the National Library of Medicine's Medline database from 1966 to February 1998 using the medical subject headings "myasthenia gravis" (restricted to the surgery subheading) and "thymectomy." To identify articles published before 1966, or missed by our original search strategy, we reviewed the references of the identified articles.We classified the resulting articles into the following categories: Class II, controlled but nonrandomized studies describing outcomes in MG patients with and without thymectomy; and Class III, uncontrolled case series describing outcomes in patients with or without thymectomy.Within a given controlled (Class II) study, we planned to describe the therapeutic effect of thymectomy by comparing the rate MG patients receiving thymectomy achieved desirable outcomes with the rate MG patients not receiving thymectomy achieved desirable outcomes. The nonrandomized nature of Class II studies often introduces differences in the baseline characteristics of the thymectomy and nonthymectomy patient groups that can effect MG outcomes independent of thymectomy. To the extent possible, we planned to adjust for these confounding differences in baseline prognostic characteristics. In the absence of randomized controlled trials, such adjustments are critical for estimating the actual therapeutic effect, if any, of thymectomy. 6Between uncontrolled (Class III) studies, comparisons of outcome rates in thymectomy and nonthymectomy MG patients introduce additional confounding baseline differences.6 These additional confounde...

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Section: Figure (A-d) Relative Rate Of Outcomes (With 95% Confidencementioning

confidence: 97%

Section: Figure (A-d) Relative Rate Of Outcomes (With 95% Confidencementioning

confidence: 99%

“…12,17,25,26,29,33 Age and gender. The studies described by Rodriguez et al, 25 Buckingham et al, 27 and Simpson 34 allowed us to determine relative outcome rates in the male MG subgroup.…”

Section: Figure (A-d) Relative Rate Of Outcomes (With 95% Confidencementioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Practice parameter: Thymectomy for autoimmune myasthenia gravis (an evidence-based review) [RETIRED]

2000

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Regional Curare Test in Evaluation of Ocular Myasthenia

Horowitz¹,

Genkins²,

Kornfeld³

et al. 1975

Archives of Neurology

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In 7 of 14 patients with clinically restricted ocular myasthenia gravis, the regional curare test showed latent peripheral involvement. The test consisted of the intravenous administration of 0.2 mg d-tubocurarine into an ischemic arm followed by repetitive supramaximal percutaneous electrical stimulation of the median or ulnar nerves. This produced a decrease in the amplitude of the initial evoked potential and a decrement of greater than 10% in the amplitude of the succeeding three to five potentials at rates of 3, 5, or 15 stimuli/sec. Three patients underwent transcervical thymectomy with subsequent improvement in both electrical and clinical findings. Evaluation of all patients with ocular myasthenia gravis should include regional curare testing of clinically uninvolved peripheral nerves. Thymectomy should be considered for patients with abnormal results.

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