title: Robotic thymectomy in patients with myasthenia gravis: neurological and surgical outcomes.
abstract: OBJECTIVE
  Thymectomy is frequently used in the treatment of myasthenia gravis (MG). But indication, timing or surgical approach remain controversial. This study reports our experiences with robotic thymectomy and surgical and neurological outcomes in a large cohort of patients with MG.
  
  
  METHODS
  We retrospectively analysed the outcome of 125 patients with MG who underwent a robotic thymectomy using the da Vinci Surgical System (Intuitive Surgical, Inc., Sunnyvale, CA, USA) between 2004 and 2012. The Myasthenia Gravis Foundation of America (MGFA) Classification was used to determine preoperative and postintervention status.
  
  
  RESULTS
  Ninety-five women and 30 men underwent a robotic thymectomy. One hundred patients had a neurological follow-up of more than 12 months. Preoperative most severe MGFA classification was Stage I in 11 patients (8.8%), Stage IIA in 18 patients (14.4%), Stage IIB in 18 patients (14.4%), Stage IIIA in 7 patients (5.6%), Stage IIIB in 29 patients (23.2%), Stage IVA in 10 patients (8.0%), Stage IVB in 29 patients (23.2%) and Stage V in 3 patients (2.4%). Median surgical procedure time was 123 min (range 45-353 min). There were no major perioperative complications or deaths. The median postoperative hospital stay was 3 days (range 2-24 days). Histological analysis showed thymic remnant tissue in 41 patients (32.8%), follicular hyperplasia in 52 patients (41.6%), thymoma in 31 patients (24%), lipoma in 1 patient (0.8%) and a cyst in 1 patient (0.8%). Patients with thymic remnant tissue were significantly more preoperative steroid users compared with the follicular hyperplasia group (P = 0.02). With a median follow-up of 33 months (range 12-104 months), 77% of the patients showed neurological improvement. Three-year probability remission rate [complete stable remission (CSR) and pharmacological remission] is 28.2%. Patients who were not treated with prednisolone preoperatively showed a significant higher CSR than patients who did take prednisolone (P = 0.014). No significant difference was observed regarding timing of surgery (P = 0.37).
  
  
  CONCLUSIONS
  Robotic thymectomy in patients with MG is safe and feasible. A neurological benefit and decreased use of steroids can be obtained in the majority of patients. No significant difference in neurological outcome was observed as the result of timing of robot thymectomy after the onset of MG.
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Centre, Maastricht and GROW Research Institute for Oncology and Developmental Biology, Maastricht University, Maastricht, Netherlands Department of Pulmonology, Maastricht University Medical Centre, Maastricht and GROW Research Institute for Oncology and Developmental Biology, Maastricht University, Maastricht, Netherlands.
authors.forename: Marlies
authors.initials: M
authors.lastname: Keijzers
authors.affiliation: Department of Neuroscience, The School for Mental Health and Neuroscience, Maastricht University, Netherlands.
authors.forename: Marc
authors.initials: M
authors.lastname: de Baets
authors.affiliation: Department of Pulmonology, Maastricht University Medical Centre, Maastricht, Netherlands.
authors.forename: Monique
authors.initials: M
authors.lastname: Hochstenbag
authors.affiliation: Department of Pathology, Maastricht University Medical Centre, Maastricht, Netherlands.
authors.forename: Myrurgia
authors.initials: M
authors.lastname: Abdul-Hamid
authors.affiliation: Department of Pathology, Maastricht University Medical Centre, Maastricht, Netherlands.
authors.forename: Axel
authors.initials: A
authors.lastname: Zur Hausen
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Centre, Maastricht, Netherlands.
authors.forename: Marcel
authors.initials: M
authors.lastname: van der Linden
authors.affiliation: Department of Neurology, University Medical Centre Groningen, Groningen, Netherlands.
authors.forename: Jan
authors.initials: J
authors.lastname: Kuks
authors.affiliation: Department of Neurology, Leids University Medical Centre, Leiden, Netherlands.
authors.forename: Jan
authors.initials: J
authors.lastname: Verschuuren
authors.affiliation: Clinical Epidemiology and Medical Technology Assessment, Maastricht University Medical Center, Maastricht, Netherlands.
authors.forename: Fons
authors.initials: F
authors.lastname: Kessels
authors.affiliation: Department of Pulmonology, Maastricht University Medical Centre, Maastricht and GROW Research Institute for Oncology and Developmental Biology, Maastricht University, Maastricht, Netherlands.
authors.forename: Anne-Marie C
authors.initials: AM
authors.lastname: Dingemans
authors.affiliation: Department of Cardiothoracic Surgery, Maastricht University Medical Centre, Maastricht, Netherlands CARIM School for Cardiovascular Diseases, Maastricht University, Maastricht, Netherlands j.g.maessen@mumc.nl.
authors.forename: Jos
authors.initials: J
authors.lastname: Maessen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005260:Female; D006801:Humans; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000473:pathology / Q000601:surgery*; D061646:Operative Time; D012189:Retrospective Studies; D065287:Robotic Surgical Procedures / Q000009:adverse effects / Q000379:methods*; D013934:Thymectomy / Q000009:adverse effects / Q000379:methods*; D013950:Thymus Gland / Q000473:pathology / Q000601:surgery; D016896:Treatment Outcome; D055815:Young Adult
keywords: Minimally invasive surgery; Myasthenia gravis; Robotic thymectomy