Outcomes after 151 extended transcervical thymectomies for myasthenia gravis

Abstract

Background: The ideal operative technique for thymectomy in myasthenia gravis (MG) remains controversial. We present the largest series of extended transcervical thymectomy to provide outcomes data to compare with transsternal procedures.

Methods: A retrospective chart review/interview was made of 164 patients operated upon from 1992 to 2004. Complete remission (CR) was defined as asymptomatic off medication for 6 months or asymptomatic on low-dose single-drug therapy (< or = 10 mg/d prednisone or < or = 150 mg/d azathioprine). A modified Osserman classification based upon the Myasthenia Gravis Foundation of America quantitative disease severity score was employed.

Results: The overall complication rate was 7.3%, and nearly all procedures were outpatient. Mean age at surgery was 43 years, and mean preoperative Osserman class was 2.3 (21% class 1; 39% class 2; 28% class 3; 12% class 4). Mean length of follow-up was 53 months. Mean postoperative Osserman class was 1.0. Nineteen percent of patients failed to improve. The crude cumulative CR rate was 37% (n = 58). Kaplan-Meier estimates of CR were 43% and 45% at 3 and 6 years, respectively. On multivariate analysis, only preoperative disease severity was significantly (inversely) associated with Kaplan-Meier CR rates. Longer-term follow-up (83 months) of only the earlier patients shows preserved CR rates (46%).

Conclusions: This largest series of extended transcervical thymectomy for MG confirms that the 5-year Kaplan-Meier CR rate is comparable with that obtained after transsternal procedures. Patients with less severe disease have higher CR rates. Complete responses are durable, as the CR rate remains stable with extended follow-up.