Myasthenia gravis (MG) is a neuromuscular disorder. Neuromuscular disorders involve the muscles and the nerves that control them. While medications are widely used in the treatment of MG, we specialize in robotic thymectomy, using the da Vinci surgical robot for our thymoma surgery. With three tiny incisions in the right chest, we perform a complete removal of the thymus.
Myasthenia gravis (MG) is a neuromuscular autoimmune disease characterized by weakness of voluntary muscles. The weakness worsens with increased activity and decreases with rest. Myasthenia gravis occurs in all races, both genders, and at any age, but it is more common in young women and older men. Most muscle groups can be affected, but the muscles that control the eyes are more frequently affected. MG is caused by antibodies directed against the muscle receptors that control muscle contraction. When the number of receptors decreases, the muscle is unable to contract and weakness starts.
MG classification was developed by the Myasthenia Gravis Foundation of America and is based on symptoms:
The most common symptom of MG is easy fatigability. Muscles become progressively weaker with activity and get stronger with rest. The muscles that control the eyes and eyelids are most commonly affected causing double vision (diplopia), and drooping eyelid (ptosis). When the muscles controlling chewing and swallowing are impacted, swallowing difficulties, gagging, drooling or choking can result. When other muscles are affected, difficulty climbing stairs or an inability to lift heavy objects can take place. Difficulty breathing is a less common symptom, occurring when the chest wall muscles are involved.
Other potential symptoms include: difficulty talking, drooping head, facial paralysis or weakness of the facial muscles, hoarseness or changing voice, double vision, and difficulty maintaining a steady gaze.
A complete physical examination by a physician who has experience with MG is essential. Many patients will have confusing factors that may make the diagnosis difficult. Sound clinical judgement is important. Antibodies against acetylcholine receptors are present in the blood serum of 85 percent of patients with MG and when present is indicative of disease. Eletromyography, a test that checks the health of the muscles and the nerves that control the muscles, stimulates a nerve-muscle unit and can provide evidence of early onset of fatigue after repeated stimuli. Sometimes, response to medical therapy is used as a diagnostic test.
Medications that inhibit the degradation of acetylcholine (Acetylcholinesterase inhibitors) are widely used in the treatment of MG. The most common are neostigmine and pyridostigmine. Immunosuppressive drugs such as steroids or azathioprine may be used in combination with acetylcholinesterase inhibitors, but those may take several weeks to take full effect.
Surgical removal of the thymus, or thymectomy, is one of the weapons doctors may use to help patients with MG. It involves the complete removal of the thymus and all thymic tissue that surrounds it. In most patients, the removed thymus will be normal, in some, a condition called thymic hyperplasia will be found. Thymoma (a cancer of the thymus), may be present in 15 to 25 percent of patients.
Surgical options include transsternal thymectomy (cutting the breastbone like in heart surgery), transcervical thymectomy (a collar incision in the neck), and robotic thymectomy. We specialize in robotic thymectomy and with three tiny incisions in the right chest, we perform a complete removal of the thymus. Our work shows that robotic thymectomy is superior to transsternal thymectomy, decreasing blood loss, hospital stay and complications. Others have also shown the superiority of robotic thymectomy to other surgical methods in patients with myasthenia gravis. Most patients are discharged the next day of their surgery and usually resume normal activities in one-to-two weeks.