Researchers presented findings on several
exciting new advancements in osteoporosis treatment at the meeting of
the World Congress on Osteoporosis 2000 in Chicago, Illinois this June. Among the
presentations were studies of a minimally invasive spinal treatment called kyphoplasty and
a new bone forming-agent called parathyroid hormone that helps vertebrae increase in
size. Researchers were optimistic about both therapies as well as the use of the
newly FDA approved drug, Actonel
(generic name, risedronate) in women and Fosamax
(generic name, alendronate) in women and men.
Osteoporosis is a degenerative bone
disease that primarily affects post-menopausal women. According to new estimates by the
National Osteoporosis Foundation, approximately one in two women and one in eight men over
age 50 have osteoporosis. Osteoporosis affects roughly 25 million Americans
and is currently one of the most under-diagnosed and under-treated disorders in medicine.
Placement of Orthopaedic
Balloon Relieves Spinal Pain
Researchers presented promising results
of studies on an experimental new minimally invasive technique to relieve spinal
pain. The procedure, called kyphoplasty, can be performed under local anesthesia and
involves using x-ray (fluoroscopy) guidance to help the surgeon
place a hollow needle into the collapsed vertebra. Once the needle is placed, a
small orthopaedic balloon is then inserted through the needle and into the vertebra.
When the balloon gently inflates, it restores the soft bone to its natural shape.
The surgeon then uses a special liquid cement (methylmethacrylate) to fill the cavity
inside the bone.
Researchers found that kyphoplasty
provided rapid pain relief from spinal pain and vertebral compression fractures in 96% of
patients. Frank M. Phillips, MD of the University
of Chicago Spine Center performed many of the procedures for one study and calls
kyphoplasty a significant step forward in treating osteoporotic spinal fractures.
The researchers say that kyphoplasty
may have fewer shortcomings than vertebroplasty, another
minimally invasive procedure that involves using special liquid cement to reduce spinal
pain. However, additional studies are needed to confirm the benefits of kyphoplasty
versus standard vertebroplasty.
With vertebroplasty, there is potential
for leakage due to the high pressure required to insert the liquid cement. There is
also the possibility that the spinal deformity cannot be corrected with
vertebroplasty. However, most patients do not experience severe complications from
the procedure.
“There is no current scientific
proof that kyphoplasty is safer or more effective [than vertebroplasty],” said
Jonathan Wiener, MD, a neuroradiologist at Boca Raton Community Hospital Boca Raton in
Florida who performs vertebroplasty. “Vertebroplasty has been performed in
France since 1984 and in the United States for more than five years.”
Currently, kyphoplasty is only being
performed at a handful of locations across the United States (such as St. Anthony Central
Hospital in Denver, Colorado). Researchers at the World Congress on Osteoporosis
2000 emphasized that patients must be carefully evaluated to determine whether they are
candidates for kyphoplasty. Patients who undergo the procedure within eight weeks of
a spinal fracture typically have better results, according to early research.
Parathyroid Hormone Helps
Decrease Vertebral Fractures
An experimental new bone-forming agent
called parathyroid hormone (PTH) is also showing promise when used with estrogen replacement therapy (ERT) in women with
osteoporosis, according to researchers. In a study of 52 women with osteoporosis,
women who took PTH along with ERT were able to increase their bone mass in the spine and
total hip after one year of therapy.
One study presented at the World
Congress on Osteoporosis 2000 found that PTH actually increased the size of
vertebrae in women, not just their bone mineral density.
These findings show that PTH may be important in rebuilding bone strength and preventing
future fractures.
Researchers believe that PTH works by
increasing the activity of bone forming cells called osteoblasts. This differs from existing osteoporosis medications that
typically work by decreasing the activity of osteoclasts, cells that break down
bone.
Though additional clinical trials with PTH are needed,
researchers are optimistic. Felicia Cosman, MD, clinical director of the National
Osteoporosis Foundation, said that the findings presented at the World Congress on
Osteoporosis 2000, are the first data that show with certainty that PTH can reduce the
risk of vertebral fractures, compared with estrogen alone. Interestingly, one full
year after the women discontinued PTH, most of the bone mass gained during treatment was
retained as long as ERT was continued.
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References
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