Robotic Extended Thymectomy in Late-Onset Myasthenia Gravis: A 21-Year Retrospective Cohort Study of 172 Patients

The safety and feasibility of robotic-assisted (RATS) thymectomy for myasthenia gravis (MG) with onset age ≥ 50 years remain unverified, particularly in very late-onset MG (V-LOMG).

Patients were classified into late-onset MG (LOMG, 50-64) and very late-onset MG (V-LOMG ≥ 65) based on age of onset. Composite neurological remission (CNR) included complete stable remission (CSR), pharmacologic remission (PR), and minimal manifestations-0 (MM-0), while favorable outcomes comprised CNR and MM1-3.

Among 1041 patients, 172 with MG onset at ≥ 50 years who underwent RATS extended thymectomy were included in the final analysis. The LOMG group comprised 104 patients (45.2% male), while the V-LOMG group included 68 patients (60.3% male). V-LOMG patients had more preoperative MG crises, shorter onset-to-thymectomy intervals, heavier thymic specimens, and less hyperplasia. In ocular-onset MG, generalization was more frequent in LOMG than in V-LOMG. No significant differences were found in other baseline characteristics, perioperative parameters, postoperative complications, and adverse composite outcomes. At a 5.1-year mean follow-up, the V-LOMG group had slightly higher CSR (7.4% vs. 6.7%), CNR (16.2% vs. 11.5%), and favorable outcome rates (52.9% vs. 45.2%) than the LOMG group, with no statistical significance. Both groups, especially V-LOMG (16.0 mg vs. 2.1 mg, p < 0.001), showed a significant corticosteroid dose reduction at the last follow-up, confirming the steroid-sparing effect of thymectomy.

RATS extended thymectomy appears to be a safe and feasible treatment for patients with MG of onset at age ≥ 50 years, including those with V-LOMG, demonstrating a significant steroid-sparing effect while maintaining favorable neurological outcomes.