Robotic thymectomy in patients with myasthenia gravis: neurological and surgical outcomes.
OBJECTIVES:
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 analyzed 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 post intervention 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.
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Published by: Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery.
The first reported use of thymectomy in patients with nonthymomatous myasthenia gravis was 75 years ago.1 Of six patients who underwent surgery, three had a favorable response. Subsequent retrospective studies have shown benefits of thymectomy in patients with nonthymomatous myasthenia gravis but with widely varying rates of clinical improvement or remission. A compilation of retrospective studies comparing surgery with medical management did not show a difference in remission rates.2 Two studies that showed clinical improvements after thymectomy indicated that benefit occurred in the first few years after the procedure, but after 5 years, rates of clinical improvement were similar among surgically treated patients and those who were treated medically.3,4 Observational studies have not shown benefits of thymectomy, perhaps because of the effectiveness of modern immunotherapeutic approaches.5
Despite calls for a randomized, controlled study, data are lacking, and uncertainty persists regarding the benefit of thymectomy and the clinical characteristics of the patients who should be offered the procedure.6,7 A systematic review8 of articles describing outcomes in 21 cohorts of patients with myasthenia gravis pointed out numerous methodologic flaws that prevented definite conclusions to be drawn regarding the benefits of thymectomy in patients with nonthymomatous myasthenia gravis.
Glucocorticoids have been widely used for the treatment of myasthenia gravis either as the sole therapy or with thymectomy.9 Although adverse effects are not common with thymectomy, the procedure can cost up to $80,00010 and can be associated with operative complications that need to be weighed against benefits. Glucocorticoids and other immunosuppressive agents place patients at risk for adverse events, some of which are life-threatening, and affect quality of life. Therefore, establishing the role of thymectomy in patients receiving glucocorticoids to manage myasthenia gravis would guide decisions regarding treatment and the costs of health care.
We conducted the Thymectomy Trial in Non-Thymomatous Myasthenia Gravis Patients Receiving Prednisone Therapy (MGTX), an international, randomized, single-blind (rater-blinded) trial, to determine whether extended transsternal thymectomy combined with a standardized prednisone protocol would be superior to prednisone alone after 3 years, with respect to lessening myasthenic weakness, lowering the total dose of prednisone, and enhancing quality of life. Extended transsternal thymectomy was chosen because it provides reproducible resection of the maximal amount of thymic tissue with low morbidity and a limited risk of phrenic-nerve injury.11
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Article by: The New England Journal of Medicine
