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

## TL;DR

Robotic thymectomy is safe and effective for late-onset myasthenia gravis patients aged 50 and older, including those over 65.

## Contribution

Demonstrates the safety and steroid-sparing effect of robotic thymectomy in very late-onset myasthenia gravis patients.

## Key findings

- Robotic thymectomy achieved favorable neurological outcomes in late-onset MG patients.
- Both late- and very late-onset MG groups showed significant corticosteroid dose reduction.
- Perioperative outcomes were comparable between late- and very late-onset MG subgroups.

## Abstract

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.

This 21‐year retrospective cohort study evaluated the safety and long‐term outcomes of robotic extended thymectomy in 172 patients with late‐onset myasthenia gravis (onset age ≥ 50 years). Both late‐ and very late‐onset subgroups showed comparable perioperative outcomes and achieved favorable neurological remission. A significant corticosteroid‐sparing effect was observed at long‐term follow‐up, particularly in the very late‐onset group.