from the Physician Update March/April 2005 - By S. Farrer
Georgetown University Hospital now offers minimally invasive surgery to remove
the thymus of people with myasthenia gravis, giving these patients hope for a
cure without the pain, extended recovery time and risks associated with traditional
sternotomy.
 |
| Dr. Blair Marshall (right), standing
above the patients head, dissects out the thymus gland behind the
breast bone, through the neck incision. She is assisted by Dr. Krit
Kitisin. |
|
The outpatient procedure, known as a transcervical thymectomy, involves removal
of the thymus, a gland located behind the breast bone, through a small incision
in the neck. Initially, the neck portion of the gland is dissected. Then, a
specially designed retractor is placed under the sternum, allowing the surgeon
to see the rest of the thymus in the chest through the neck incision. The surgery
is done under general anesthesia and can usually be completed in 60 to 90 minutes.
The patient goes home the same day and may return to work and other normal activities
within a week.
In contrast, sternotomy, a conventional approach to thymectomy that involves
sawing open the sternum, requires a five- to seven-day hospital stay and six
weeks of recovery at home.
“Patients with myasthenia are usually quite fragile and are at risk
for significant complications following sternotomy. Also, there is considerable
pain associated with this approach,” says M. Blair Marshall, MD, chief
of Georgetown’s Division of Thoracic Surgery and one of a small number
of thoracic surgeons nationwide who are trained to perform transcervical thymectomy.
“In addition, the traditional open approach can adversely affect one’s
breathing, which is not good for patients with myasthenia. With the transcervical
approach, we use lighter anesthesia. This, combined with the decreased pain,
results in minimal impact on their breathing.”
Myasthenia gravis is a rare, chronic autoimmune disorder characterized by
fluctuating weakness in the voluntary muscles. It appears to originate in the
thymus gland, a lymphatic organ located behind the breastbone that plays an
important role in the immune system’s development early in life.
“After childhood and into adulthood, the thymus gland becomes smaller
and is mostly replaced by fat,” says Dr. Marshall. “However, it
still seems to have some activity and is thought to be the source of auto-antibodies
seen in this disorder. The antibodies attack the acetycholine receptors, which
are the receptors for nerves that activate the muscles of the eye and those
used in swallowing and breathing.”
Early signs of myasthenia gravis include blurred or double vision caused by
ocular muscle weakness, difficulty swallowing, and slurred speech. Other symptoms
are drooping eyelids, varying degrees of muscle weakness in the extremities
and neck, changes in facial expression, and breathing problems. The disease
can arise at any age, but it most often affects adult women under age 40 and
men over age 60.
Thymectomy can lessen or eliminate myasthenia’s impact in many patients,
particularly those in the early stages of the disease. According to the National
Institute of Neurological Disorders and Stroke, thymectomy reduces symptoms
in more than 70 percent of patients without thymus tumors, and some individuals
experience complete remission.
Other treatments include use of anticholinesterase agents and immunosuppressive
drugs, and plasmapheresis—filtering the antibodies from the patient’s
blood.
Dr. Marshall reflects that in the past, because of the recovery period and
complications, neurologists treating myasthenia patients tended to wait until
the condition was at an advanced stage before considering thymectomy. Today,
neurologists have the option of recommending outpatient transcervical thymectomy
in the early stages of the disease, particularly for patients with newly diagnosed
myasthenia. Patients in the early stages of the disease have the highest chance
of being cured with thymectomy.
“I think that any patient with a new diagnosis of myasthenia should
have a thymectomy, especially if it can be done as a minimally invasive outpatient
procedure,” she says. “Why would one wait, as the chance of being
cured goes down as the disease progresses?”
Dr. Marshall notes that the transcervical approach is appropriate for many,
but not all myasthenia patients. For example, it is contraindicated for patients
whose necks cannot be extended for the surgery and those with thymomas, or tumors
of the thymus gland, that are greater than four centimeters in diameter.
She also explains that it may take six to 12 months after thymectomy for patients
to notice a significant reduction in symptoms.
“Unfortunately, we can’t predict which patients are going to be
cured by thymectomy, but the chance of cure is highest for those patients in
the early stages of their disease,” Dr. Marshall says. “Even for
those who are not cured, most patients’ symptoms are improved, and their
quality of life is improved.”
For more information, contact Georgetown Physician Access at 202-342-3300
or 1-800-442-4200 outside the DC metro area.
