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Thymus

Going after Myasthenia Gravis through the Chest

One of the most successful therapies for myasthenia gravis (MG), a neurological disorder, is performed by a cardio-thoracic surgeon

Myasthenia gravis (MG) is a neurological disorder.  It causes fatigue, muscle weakness, and drooping eyelid.  Any neurologist will tell you, it’s a difficult disease to treat.  But interestingly, one of the most successful therapies for MG is administered by a thoracic surgeon – the same specialist who performs lung, esophageal or chest wall surgery.

The connection between MG and the chest is a gland known as the thymus – a small shapeless mass located inside the chest under the sternum. An important player in immune system development  in infancy , the thymus doesn’t do much for adults except cause trouble.

Nobody knows  precisely what causes MG, but about 10 percent of people who have the disease also have a tumor on the thymus known as a thymoma.  As you might guess, surgically removing the thymus relieves the symptoms of MG in these patients.  But what you might not guess is that a thymectomy (thymus removal) also relieves symptoms in MG patients who don’t have thymomas. Up to 70% of patients will have either complete relief of their symptoms or a significant reduction in their medication needs following thymectomy. Thirty percent of non-tumorous MG patients enjoy significant relief from symptoms after a thymectomy. Another 30 percent will have reduced need for medications to treat MG.

Nobody is quite sure how this works, but it does. Every year, hundreds of neurologists refer patients for this type of surgery.

Daniel Raymond, MD, of Cleveland Clinic’s Department of Thoracic  and Cardiovascular Surgery, says there are a variety of alternatives for removing the thymus, including minimally invasive techniques.

The thymus may be removed through an open incision in the chest like that for an open heart surgery.  Or it may be taken out through a small horizontal incision at the bottom of the neck, like a thyroid removal.  The thymus may also be removed under the guidance of fiber-optic instruments through a small incision in the upper portion of the chest.  This latter technique may also be done with robotic assistance.

The choice of which approach to take depends on the location and extent of the thymus, and how much associated fat and other tissue needs to be removed.  The  minimally invasive options offer similar results to the open procedure , but must should be done by a very skilled surgeons with appropriate experience. .

“We’d like to be able to prove the value of surgery and particular surgical techniques for the treatment of MG,” says Dr. Raymond.  “But double-blind testing (the gold standard in medical research) is difficult to arrange for surgical procedures.  By the time a patient gets to us, they ha’ve made up their mind to have the surgery, and very understandably don’t want to risk being randomized into the group that doesn’t get surgical treatment.”

But most MG patients who improve from surgery are free from many symptoms after a year.  Dr. Raymond believes that many more people with MG could benefit from surgical treatment.   He notes that the American Association of Neurologists supports consideration of MG patients for surgery, observing that they are two times as likely to enjoy medical remission as non-surgery patients.

“If you’ve been diagnosed with MG,” he says, “ask your neurologist about possible surgical treatment for your symptoms.  Your neurologist will be able to refer you to a qualified surgeon to perform this operation.  At Cleveland Clinic, we work closely with neurologists to give every patient the best outcome for this difficult disease.”

June is National Myasthenia Gravis Awareness Month

Tags: cleveland clinic, myasthenia gravis, thoracic surgery, thymus
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  • Danbee13

    It’s my understanding that thymectomies aren’t effective for mg patients who have had the disease for many years as opposed to those who have been recently diagnosed.

    • The_Beating_Edge_Team

      Dear Danbee13, I spoke to Dr. Raymond.  He stated, “Factors that predict success include 1)response to medical therapy; 2) short duration from diagnosis to surgery; and 3) young age.  We will still perform in patients with longstanding disease but the efficacy is diminished.”  betsyRN