Robotic-assisted minimally invasive thymectomy for myasthenia gravis with thymoma

Abstract

Central MessageThe robotic approach to thymectomy using bilateral simultaneous thoracoscopy provides excellent visualization to allow safe and complete dissection around critical structures.Myasthenia gravis (MG) is a chronic autoimmune disorder caused by antibodies against the nicotinic acetylcholine receptors at the neuromuscular junction. This results in skeletal muscle weakness in the ocular, respiratory, bulbar, and limb distributions. Its prevalence is approximately 250 cases per 1 million people. It is medically treated primarily with acetylcholinesterase inhibitors and steroids. Immunosuppressive therapy, plasmapheresis, and/or intravenous immunoglobulin may also be indicated in advanced cases. MG may occur with or without the presence of thymoma and is a recognized paraneoplastic syndrome of thymoma affecting approximately one third of patients with thymoma. On the contrary, about 10% of patients with primary MG will have an associated thymoma, and its incidence increases with age.1Gilhus N.E. Myasthenia gravis.N Engl J Med. 2016; 375: 2570-2581Crossref PubMed Scopus (390) Google Scholar Primary surgery is indicated in most instances of early-stage thymoma and those cases associated with any type of MG.2Davenport E. Malthaner R.A. The role of surgery in the management of thymoma: a systematic review.Ann Thorac Surg. 2008; 86: 673-684Abstract Full Text Full Text PDF PubMed Scopus (115) Google Scholar In the case of nonthymomatous MG, current evidence and guidelines have recently strengthened the indications for surgical over medical therapy alone in the majority of cases and recommend thymectomy for patients who have positive acetylcholine receptor antibodies, general type MG, short disease duration (<5 years), age younger than 65 years old, and/or symptoms not controlled with medication.1Gilhus N.E. Myasthenia gravis.N Engl J Med. 2016; 375: 2570-2581Crossref PubMed Scopus (390) Google Scholar,3Wolfe G.I. Kaminski H.J. Aban I.B. Minisman G. Kuo H.C. Marx A. et al.Randomized trial of thymectomy in myasthenia gravis.N Engl J Med. 2016; 375: 511-522Crossref PubMed Scopus (221) Google Scholar,4Okusanya O.T. Hess N. Christie N. Luketich J.D. Sarkaria I.S. Improved outcomes with surgery vs. medical therapy in non-thymomatous myesthenia gravis: a perspective on the results of a randomized trial.Ann Transl Med. 2016; 4: 526Crossref PubMed Scopus (4) Google Scholar Before surgery, patients should generally be well-recovered from acute exacerbations of MG or crisis, minimized on their steroid dose as feasible, and should be maintained on their cholinesterase inhibitors (pyridostigmine) up to the day of surgery. If indicated for advanced cases, we prefer plasmapheresis and/or immunoglobulin therapy to have been performed within one week of surgery when feasible.IndicationOur patient is a 63-year-old man with a history of generalized MG (primarily with occulo-bulbar and limb-girdle symptoms) on prednisone and pyridostigmine, presenting with a well-circumscribed 3-cm anterior mediastinal mass suspicious for noninvasive thymoma.ProcedureIt must be understood that several viable alternatives to this procedure using different numbers and configurations of port sites and combinations of instrumentation and energy devices are described both anecdotally and formally in the literature by other groups and/or surgeons. The following descriptions and accompanying Video 1 simply represent our approach to robotic-assisted thymectomy, which has evolved over time (and likely will continue to evolve). It does not implicitly and/or overtly intend to invalidate or diminish the numerous described variations in the literature, which are beyond the scope of this article to fully enumerate.5Hess N.R. Sarkaria I.S. Pennathur A. Levy R.M. Christie N.A. Luketich J.D. Minimally invasive versus open thymectomy: a systematic review of surgical techniques, patient demographics, and perioperative outcomes.Ann Cardiothorac Surg. 2016; 5: 1-9PubMed Google Schol