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Thoracoscopic Thymectomy for Juvenile Myasthenia Gravis In Children

Saturday, October 20, 2012: 1:32 PM
Napoleon Ballroom (Hilton Riverside)
Govardhana Yannam, MD1, Russell L. Griffin, PhD2, Scott A. Anderson, MD1, Mike K. Chen, MD1, Carroll M. Harmon, MD, PhD1 and Elizabeth A. Beierle, M.D.1, (1)Pediatric Surgery, The Children's Hospital of Alabama, University of Alabama at Birmingham, Birmingham, AL, (2)Epidemiology; Center for Clinical Translational Science, University of Alabama at Birmingham, School of Public Health, Birmingham, AL

Purpose: Experience using thoracoscopic thymectomy (TT) in the management of juvenile myasthenia gravis (JMG) in children is limited. The probability of remission or improvement of symptoms after thymectomy is higher in Caucasians, anti -acetyl cholinesterase antibody (AChR-ab) seropositive and prepubertal patients. The present study was designed to assess the effectiveness and long-term outcome of TT in patients with JMG and its role in non-caucasian, AChR-ab seronegative, and postpubertal JMG patients.

Methods: After IRB approval, a retrospective review was performed evaluating children who had TT for JMG at our center from 1999-2011. The demographics, pre- and post-operative symptoms and therapy, intra-operative events and post-operative complications were reviewed. Osserman’s criteria were used to assess the disease severity and DeFilippi classification was used to assess the post-operative benefit.

Results: A total of 12 children underwent TT.  The median age at surgery was 11.7 years (3.7 -16.4 years). There were 11 females, and 5 were non-caucasian.  Seven patients were AChR-ab seronegative.  All except one, with  suspicion of thymoma, had normal chest CT scans. Based on Osserman’s criteria, one patient was stage I, 7 patients were stage IIA and the remaining patients were stage IIB. Six patients were postpubertal. Six children were operated within one year after diagnosis. The mediastinum was accessed through the left chest in 9 patients, through the right chest in 2 and one child required bilateral thoracoscopy.  There were no conversions to an open procedure.  During the same time period, one child underwent open thymectomy. Mean operative time, blood loss and hospital stay were 130 minutes, 18 mL and 3 days (range, 2-71 days), respectively. There was no operative mortality. One patient died 6.6 years after TT due to complications of JMG. Histopathology of the thymus revealed follicular lymphoid hyperplasia (n=10), acute hemorrhage and congestion (n=1) and features of normal involution (n=1).  Mean follow-up after surgery was 4.5 years.  At the time of last follow-up, 2 patients each were class 1 and class 3, 6 patients were class 4, and 2 were class 5 according to the DeFilippi classification. To assess the benefit of TT, DeFilippi class 1-3 were considered responders (n=4) and class 4 and 5 were considered non-responders (n=8). Severity and duration of illness, race, pubertal status and AChR-ab status could not predict a favorable outcome.

Conclusion: TT may be utilized with minimal complications for the treatment of JMG. One third of the patients had a favorable response and benefited from the procedure.