Surgery for Myasthenia Gravis: Understanding the Benefits and Potential Risks

Surgery for myasthenia gravis—thymectomy—may be an option if your symptoms are caused by an enlarged thymus. It is the standard treatment if you have a thymus tumor (thymoma). 

The thymus gland produces infection-fighting white blood cells called T cells, and the gland plays a pivotal role in the development of myasthenia gravis (MG) [1].

In a minority of people with MG, the thymus produces antibodies directed against acetylcholine receptors in the muscles. As a result, the muscles cannot contract as usual, leading to muscle weakness and fatigue. 

The thymus typically starts to shrink after puberty, but not in people with MG. Studies show that about 7 in 10 individuals with MG have enlarged thymus glands. Likewise, nearly 1 in 10 have thymomas [2]. 
Consequently, surgical removal of the thymus (thymectomy) is a standard treatment.  

Surgery for Myasthenia Gravis: What Are the Benefits of Thymectomy?

Thymectomy is an effective treatment that not only improves long-term outcomes but also reduces the need for MG treatment. Below, we review the recent literature.  
According to a 2016 clinical trial, thymectomy plus prednisone is superior to prednisone alone for people with generalized MG. The researchers noted that [3]:

• Participants in the thymectomy (with prednisone) group had a lower average quantitative myasthenia gravis score. A lower score indicates less severe symptoms. 
• Fewer participants in the thymectomy group required immunosuppression or were hospitalized for flares. 
• Participants in the thymectomy group experienced fewer treatment-associated symptoms. 

In the same year, health experts from the Icahn School of Medicine at Mount Sinai observed similar results in their review. The review concluded that thymectomy was superior to medication-only conservative treatment in improving symptoms [4].
In a 2020 investigation, Turkish researchers evaluated the role of thymectomy on recovery. They found that about 40% of individuals who received a thymectomy within 6 months of diagnosis had a complete recovery [5].
Most notably, surgery for myasthenia gravis can improve recovery, irrespective of the type of MG or duration of the disease. 
The “International Consensus Guidance for Management of Myasthenia Gravis” recommends thymectomy [6]:

• During the early stage of the disease 
• If your symptoms don’t improve with immunotherapy 
• If you cannot tolerate the side effects of immunotherapy 

Surgery for Myasthenia Gravis: Who Is It For?

Early surgery for myasthenia gravis may be the best option for:

• Individuals with a recent diagnosis
• People with an enlarged thymus
• Young adults (typically below 50)

Note that the use of thymectomy for MG is an area of research, and more controlled trials are needed to confirm the findings. Notably, the authors of a 2019 study concluded that surgery could be an option even in elderly individuals during early diagnosis [7]. 

Surgery for Myasthenia Gravis: What Are the Complications of a Thymectomy?

No surgery is risk-free. 
Surgery-associated complications are more likely to occur in people with MG, as they can affect breathing. Fortunately, newer surgical and anesthesia techniques have dramatically reduced the risk of such complications. 
Death from thymectomy is rare and occurs in fewer than 1% of all cases, even in those with severe MG symptoms.
Complications or side effects of thymectomy can include:

• Injury to the heart, blood vessel, or nerve
• Bleeding
• Pneumothorax (collapsed lung)
• Pneumonia (lung infection)
• Fluid or blood accumulation between the lung and chest wall
• Myasthenic crisis (extremely rare)

Is Thymectomy a Major Surgery?

Because thymectomy involves the chest, it can be considered a major surgery. Thymectomy typically lasts about 3 hours. 
 

Does Surgery for Myasthenia Gravis Work Immediately?

No. You can expect your symptoms to improve in the first few months following surgery. You may also experience continuous improvements for the next 1 to 2 years. 
 

Does Myasthenia Gravis Go Away After Thymectomy?

Thymectomy may result in complete recovery in about 40% of individuals.