| Backgroud and objective: Myasthenia gravis is an autoimmune disorder mainly caused by antibodies to the muscle acetylcholine receptors (AChRs) at the neuromuscular junction. Loss of these receptors leads to a defect in neuromuscular transmission with muscle weakness and fatigue. The symptoms always get severe after activity and can be relief by rest or cholinesterase inhibitors. Thymectomy has been considered as an effective and important method of treatment of myasthenia gravis. Common surgical approaches including: transcervical thymectomy, videoscopic thymectomy, transsternal thymectomy, transcervical and transsternal thymectomy and so on. Video assisted thymectomy was introduced by Yim as aminimally invasive alternative for thymectomy in patients with myasthenia gravis. Recently, as continued progress in tools and technology for thoracoscopic surgery, this minimally invasive method gets more popular because of its less degree of tissue damage and shorter recorvery time. It has become the first choice for thmectomy in place of the traditional transsternal thymectomy. However, as a newly applied method, the surgical technique and outcomes are still controversial. The data and our experience are still not enough, so we need more research to have complete and correct comprehension for this method. A retrospective review was performed of 34 consecutive patients who underwent video-assisted thymectomy for myasthenia gravis (MG) in our hospital, and compared with patients who received transsternal (TS) extended thymectomy. The purpose of this study was to discuss the application and effectiveness of video-assisted thoracoscopic (VATS) thymectomy for myasthenia gravis (MG).Materials and methods: 34 video-assisted thymectomies for myasthenia gravis were performed in our institution between September 2007 and September 2009. We performed a retrospective review and compared with 27 MG patients who received transsternal (TS) extended thymectomy from November 2005 to May 2008. All the patients have typical clinical manifestations, such as ptosis, diplopia, dysphagia, dysarthria and limb weakness and so on. The patients were diagnosed by neostigmine test in department of neurology, and classified by Osserman classification. Before operation, they were treated by pyridostigmine or glucocorticoids to make sure they were in stable status by the minimal dose of medicine. The preoperative clinical parameters and histological diagnosis were no difference between two group. Operative time, blood loss, postoperative analgesic pethidine dose, morbidity, mortality, crisis and hosipal stay of each group were recorder and analyzed. The follow-up has been obtained through outpatient clinic visits, mail and phone conversations. The therapeutic response to thymectomy was compared with the patient's preoperative status and assessed according to the MGFA post-intervention status. Complete stable remission (CSR) was defined as no weakness or any muscle-related symptoms or signs of MG for at least 1 year, and the patient did not receive any therapy on careful examination. Isolated weakness on eyelid closure was accepted. An'improved'postoperative disease status in this study included CSR, pharmacologic remission, minimal manifestations and improved in status in the MGFA post-intervention status. Definitions of postoperative disease status'unchanged'and'worse'were according to the MGFA post-intervention status. Chest CT scan were taken for patients with thymoma. Categorical variables were presented by frequency (%) and analysed by Fisher's exact test or by Pearson's chi-square test. Continuous variables were expressed as mean±stanstandard deviation (SD) and analysed by the two-sample t-test. A P-value <0.05 was considered statistically significant.Results: 34 cases of VATS group and 27 cases of TS group successfully received thymectomy and anterior mediastinal fat dissection. There were no death cases in both group. In VATS group, there was no postoperative complication, but one case with myasthenic crisis in typeⅡb was reported (2.94%). In TS group, four cases (14.81%) had postoperative complication, including"line"infection in 2 cases, 1 case of pulmonary infection, pleural effusion in 1 case. Four cases of TS group with myasthenic crisis was reported (14.81%), including typeⅡa in 1 case and typeⅡb in 3 cases. The VATS group compared with the TS group, blood loss (102.64±65.51ml vs 187.40±68.08ml), the probability of postoperative complications (0.00% vs 11.76%), postoperative analgesic pethidine dose (19.11±30.19mg vs 62.96±77.94mg) and postoperative hospital stay (9.64±5.53d vs 13.89±6.75d) were decreased. VATS group patients were followed up 6 to 28 months, (mean 12.7 months). Patients with thymoma were reviewed chest CT scan, no recurrence of thymoma was found in both group. Overall clinical improvement at follow-up was observed in 28 of 33 (84.85%) patients, with 9 of 33 (14.0%) patients in complete stable remission. There was no statistically significant (P<0.05) between the two groups.Conclusions: Video-assisted thoracoscopic extended thymectomy is safe and effective, which is more advantageous for MG patients because of less tissue injury, lighter pain, lower rate of complication, shorter hospital stay, better cosmetic result and equivalent CSR rate.
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