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

Abstract

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.

Understanding the burden of refractory myasthenia gravis

“…In addition, it is important to note that any thymectomy procedure should be performed when a patient is in a stable clinical condition. 2,77 Although thymectomy has potential benefits in terms of clinical improvement, 8,78 each thymectomy procedure is associated with considerable morbidity. The burden of surgery is particularly relevant given that these patients are experiencing a second surgical procedure (possibly major surgery) against a background of the severe disabling symptoms of refractory MG with the complicating factor of a potentially higher risk of peri-and postoperative events.…”

Therapeutic Plasma Exchange in Myasthenia Gravis: A Systematic Literature Review and Meta-Analysis of Comparative Evidence

“…In the treatment of acute MG patients, including but not limited to myasthenic crisis, TPE, and IVIG are often used interchangeably. Despite several literature reviews (14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25) on TPE, IVIG, or both, there is not a clear agreement as to which of the two acute therapy options is more effective or safer; results can vary across studies and patient types. The decision to use TPE vs. IVIG may also depend on factors such as access and convenience.…”

Der Stellenwert der Thymektomie ohne Thymom in der Therapie der Myasthenia gravis

“…Die unvollständige Resektion der Thymusdrüse führte in diversen Untersuchungen zu einer Persistenz der Symptomatik und zur Notwendigkeit der Reoperation [ 22 , 27 , 33 , 44 , 46 , 55 ]. Allerdings sind die Möglichkeiten, residuelles Thymusgewebe radiologisch darzustellen, limitiert, sodass die Indikationsstellung nicht selten klinisch erfolgt [ 49 ]. Referenzoperation bleibt die kombinierte transzervikale transsternale Thymektomie, welche durch Alfred Jaretzki in Anlehnung an den transsternalen Zugangsweg von Blalock konzipiert und propagiert wurde [ 28 ].…”